Interface Vol. 30, No. 4, Winter 2021 by The Electrochemical Society

VOL. 30, NO. 4, Wi n t e r 2 0 2 1

HYDROGEN'S

BIG SHOT H2

10 Pearls of the Journals: 30 Years of Interface 12 Meet the Candidates for Society Office

OF OF

R FAC

15 Highlights from the 240th Meeting 41 The Many Colors of Hydrogen

FUTURE ECS MEETINGS

241st ECS Meeting VANCOUVER, BC May 29-June 2, 2022

Vancouver Convention Center

242nd ECS Meeting

243rd ECS Meeting

ATLANTA, GA Oct. 9-13, 2022

with SOFC-XVIII BOSTON, MA May 28-June 1, 2023

Atlanta Hilton

Hynes Convention Center and Sheraton Boston

w e w.

244th ECS Meeting

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GOTHENBURG, SWEDEN October 8-12, 2023

Swedish Exhibition & Congress Centre

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

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FROM THE EDITOR

Who’s a Good Boy?

f you want to see what unconditional love looks like, watch a dog and their person/people reunite, independent of the time of separation. The level of joy and fullness of heart the dogs show always makes me smile, as does the transformation on the faces of the people. Even the grumpiest old man breaks into a wide smile and starts talking in a funny voice. Or so I have heard. As the saying goes, I wish I were as good as my dog thinks I am. Both long-time readers of this column as well as my several friends will know that my wife and I are proud parents of two whippets (oh, yeah, a couple of children, too, I am pretty sure). As one measure of their importance to us, they sleep in our bed, which makes a king-size bed feel more like a cot to at least one of us. For clarity, “they” refers to the dogs, not the kids. During the early days of the pandemic, our boy whippet, Bubba, had ACL surgery and recovered very well with the constant availability of his humans. And apparently his luck has not changed. Heather discovered a lump the size of a small blueberry on Bubba’s left leg while cuddling with him on the couch. Hoping it was simply a lipoma (per the Mayo Clinic, a “fatty lump,” which is coincidentally how I am often described), we scheduled a veterinarian visit. A fine needle aspiration dashed those hopes as it was a soft tissue sarcoma, and surgery was scheduled for a week later. The surgery went as well as could be expected, and the wait for the pathology began as did the nursing of Bubba back to health from the surgery. For someone whose main loves are running very fast to chase a ball or frisbee, eating, sleeping, and Heather (not necessarily in that order), having his lower leg immobilized was very tough. Through the fog of the pain medicine, he had his grumpy face on most of the time. Even treats, a word that cannot be uttered out loud in our house as expectations instantaneously follow, did not interest him. A week out, the surgeon changed his dressing, said his incision looked good, and passed us along to the oncologist. In the time of COVID, the consultation was by phone. The sarcoma was an intermediate grade, a peripheral nerve sheath tumor, for those keeping score at home. Because the location on his Achilles prevented the taking of large enough margins, more treatment was indicated. So radiation daily for several weeks is the plan, with the nearest treatment center two hours away. Heather would board me before she would allow Bubba to be boarded, so there will be a lot of road time. We’ll try to make lemonade from lemons, taking advantage of some together time. As this missive is published, we will have completed the radiation and have transitioned to watchful surveillance. This experience has stunk, does stink, and will continue to stink. Watching Bubba go through all this and to have no way to explain to him why is really rough. Despite his “I’m really tough” bark, he is really just a softie and is so scared when we take him to the vet. We are getting just a glimpse of what the parents of pediatric cancer patients go through. The point of this tale, which of course cannot be compared to what many of us have gone through over the past year, is a public service announcement to all pet people. Please make a habit of checking your pets for lumps monthly during one of your petting sprees. We all (should) do it for ourselves with self-examination as a means of early detection, but the lack of an opposable thumb makes it more difficult for our pets, so they are relying on us. Animal oncology is an amazing field, I am learning, and treatments are getting better all the time. So give your furry friends a little bigger hug than usual tonight. For a little humor now, look up zfrank1 on YouTube and his “Sad Dog Diary” and “Sad Cat Diary” which perfectly capture the different ways these two perceive their people as “Dearest Human” and “The Authorities,” respectively. To end on a positive note, this issue of Interface represents the completion of 30 years of publication. As a beginning to the celebration, we have included a list of 30 articles published in the last 30 years from Journal of the Electrochemical Society and the Journal of Solid State Science and Technology. They are listed as “pearls” because the 30th anniversary is the “pearl anniversary.” Thanks to Mary Beth Schwartz for that idea. Special thanks to Paul Cooper at ECS who painstakingly gathered the data for me. Until next time, be safe and happy. © The Electrochemical Society. DOI: 10.1149/2.001212IF

Rob Kelly Editor https://orcid.org/0000-0002-7354-0978

Published by: The Electrochemical Society (ECS) 65 South Main Street Pennington, NJ 08534-2839, USA Tel 609.737.1902, Fax 609.737.2743 www.electrochem.org Editor: Rob Kelly Guest Editors: Nemanja Danilovic, Iryna Zenyuk Contributing Editors: Donald Pile, Alice Suroviec Director of Publications: Adrian Plummer Production Editor: Kara McArthur Print Production Manager: Dinia Agrawala Staff Contributors: Frances Chaves, Genevieve Goldy, Mary Hojlo, Christopher J. Jannuzzi, Bianca Kovalenko, John Lewis, Anna Olsen, Jennifer Ortiz, Adrian Plummer, Shannon Reed, Beth Schademann, Francesca Spagnuolo Advisory Board: Brett Lucht (Battery), Dev Chidambaram (Corrosion), Durga Misra (Dielectric Science and Technology), Philippe Vereecken (Electrodeposition), Jennifer Hite (Electronics and Photonics), Mani Manivannan (Energy Technology), Cortney Kreller (High-Temperature Energy, Materials, & Processes), John Weidner (Industrial Electrochemistry and Electrochemical Engineering), Jakoah Brgoch (Luminescence and Display Materials), Hiroshi Imahori (Nanocarbons), Jim Burgess (Organic and Biological Electrochemistry), Andrew Hillier (Physical and Analytical Electrochemistry), Ajit Khosla (Sensor) Publications Subcommittee Chair: Gerardine Botte Society Officers: Eric D. Wachsman, President; Turgut Gür, Senior Vice President; Gerardine Botte, 2nd Vice President; Colm O’Dwyer, 3rd Vice President; Marca Doeff, Secretary; Gessie Brisard, Treasurer; Christopher J. Jannuzzi, Executive Director & CEO Statements and opinions given in The Electrochemical Society Interface are those of the contributors, and ECS assumes no responsibility for them. Authorization to photocopy any article for internal or personal use beyond the fair use provisions of the Copyright Act of 1976 is granted by The Electrochemical Society to libraries and other users registered with the Copyright Clearance Center (CCC). Copying for other than internal or personal use without express permission of ECS is prohibited. The CCC Code for The Electrochemical Society Interface is 1064-8208/92. Canada Post: Publications Mail Agreement #40612608 Canada Returns to be sent to: Pitney Bowes International, P.O. Box 25542, London, ON N6C 6B2 ISSN : Print: 1064-8208

Online: 1944-8783

The Electrochemical Society Interface is published quarterly by The Electrochemical Society (ECS), at 65 South Main Street, Pennington, NJ 08534-2839 USA. Subscription to members is part of membership service. © Copyright 2021 by The Electrochemical Society. *“Save as otherwise expressly stated.” Periodicals postage paid at Pennington, New Jersey, and at additional mailing offices. POSTMASTER: Send address changes to The Electrochemical Society, 65 South Main Street, Pennington, NJ 08534-2839. The Electrochemical Society is an educational, nonprofit 501(c)(3) organization with more than 8,500 scientists and engineers in over 75 countries worldwide who hold individual membership. Founded in 1902, the Society has a long tradition in advancing the theory and practice of electrochemical and solid state science by dissemination of information through its publications and international meetings.

Cummings Printing uses 100% recyclable low-density polyethylene (#4) film in the production of Interface.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

3 All recycled paper. Printed in USA.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Hydrogen's Big Shot

Vol. 30, No. 4 Winter 2021

by Nemanja Danilovic and Iryna Zenyuk

Ten Questions

for Kelly J. Speakes-Backman, Acting Assistant Secretary for Energy Efficiency and Renewable Energy, US Department of Energy

by Julie C. Fornaciari

The Chalkboard 1: The Many Colors of Hydrogen by Ahmet Kusoglu

The Chalkboard 2: How to Make Clean Hydrogen AWSM: The Advanced Water Splitting Materials Consortium by Shaun Alia, Dong Ding, Anthony McDaniel, Francesca M. Toma, Huyen N. Dinh

From Hydrogen Manifesto, through Green Deal and Just Transition, to Clean Energy Act by Plamen Atanassov, Vito Di Noto, Stephen McPhail

Hydrogen: Targeting $1/kg in 1 Decade by Bryan S. Pivovar, Mark F. Ruth, Deborah J. Myers, Huyen N. Dinh

PEM Electrolysis, a Forerunner for Clean Hydrogen by Kathy Ayers, Nemanja Danilovic, Kevin Harrison, Hui Xu

Hydrogen at Scale Using Low-Temperature Anion Exchange Membrane Electrolyzers by Sanjeev Mukerjee, Yushan Yan, Hui Xu

Hydrogen is Essential for Industry and Transportation Decarbonization by Rod Borup, Ted Krause, Jack Brouwer

Getting Hydrogen to the Gigaton Scale by Bryan S. Pivovar, Mark F. Ruth, Akihiro Nakano, Hirohide Furutani, Christopher Hebling, Tom Smolinka

the Editor: 3 From Who’s a Good Boy? the President: 7 From A Critical Aspect of Scientific Success: Perseverance

Years of Pearls from 10 30 The Electrochemical Society Journals

for Society 12 Candidates Office of the 15 Highlights 240th ECS Meeting

18 Society News Fellowship 28 Summer Reports 38 People News 39 Tech Highlights for Papers 66 Call 242nd ECS Meeting, Atlanta, GA

89 Section News 91 Awards Program 94 New Members 97 Student News On the Cover: This month's cover, an original design by Ahmet Kosuglu and Dinia Agrawala, depicts the pathways for clean (“green”) hydrogen based on either direct solar water-splitting or electrolytic water-splitting using zero-carbon electricity, against a background of a drop of water—hydrogen's main waste product.

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

FROM THE PRESIDENT

A Critical Aspect of Scientific Success: Perseverance

instein famously said “Genius is two percent inspiration, and 98 percent perspiration,” essentially saying that scientific and technological breakthroughs are based primarily on hard work. As scientists and engineers, we all know this, as it is our job to push the boundaries of discovery and advance the technologies that benefit humankind, and we all work hard to achieve this. As a society, we face urgent global challenges: climate change; energy security; scarcity of water resources; global health and disease; inadequate food supply; and degradation of the environment. The solutions to these challenges lie at the nexus of science and technology, many of which are within the purview of The Electrochemical Society, from advanced energy storage and harnessing low-carbon energy resources, to higher efficiency industrial processes, improved sanitation, cleaner water, and the detection and remediation of environmental pollutants and pathogens. Moreover, as a scientific society, our meetings and publications provide vital forums for scientists and engineers from around the world to develop interdisciplinary solutions to these global challenges. However, as pointed out by former ECS member Thomas Edison: “Many of life’s failures are people who did not realize how close they were to success when they gave up.” Essentially, hard work is not enough; we need perseverance for those discoveries to be successful. I recently presented an address on the role of perseverance in my own career, and believe perseverance is critical if ECS and society at large are to confront these global challenges. While I have every confidence in our members’ ability to address the scientific and technological challenges we face, to have the necessary impact on society we must also persevere over socio-political-economic forces that our scientific training most likely did not prepare us for. We must also be fierce advocates for the best use of scientific knowledge, including influencing government policies and fighting misinformation. The latter is no more evident than in the unfortunate politicization of the urgent need to fight climate change and to address the COVID-19 pandemic. Science denial threatens our ability to combat the global challenges we face. While this is nothing new—remember 1633 when Galileo was accused of heresy for claiming that the earth revolved around the sun—little did we imagine that we would be confronted with this issue in the 21st century! The rejection of mainstream science and medicine increasingly colors and hinders the dialog required to address global challenges.

Organized science “denialists” are increasingly attacking prominent scientists, for example, the attempts to discredit Anthony S. Fauci, MD, Director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID). Compare that to how honored and revered Dr. Jonas Salk was for developing the polio vaccine. Today, Research!America found that 81 percent of Americans could not correctly identify a single living scientist, and of the few who did, many named science celebrities and media personalities rather than actual researchers. Furthermore, researchers found that science denial has a stronger and more pervasive effect when there is no science advocate to refute false claims. Clearly, the scientist’s and engineer’s place can no longer be just in the lab. Each and every one of us must become a voice for mainstream scientific views and evidence, at the micro-level in our own communities, and at the macro-level with politicians and decision makers. The ECS community—made up of our members, volunteers, supporters, and staff—is well positioned to use its voice and expertise to ensure that the contributions science makes to society are understood and valued, and that policy decisions are grounded in scientific fact. Whether it is by encouraging students to explore science as an educational and career path; ensuring public awareness of factual mainstream science; supporting science advocacy initiatives; or writing to politicians in support of current scientific solutions and of the need for research funding to develop the scientific solutions of the future; today, perhaps more than ever before, science needs to be a driving force behind the development and implementation of meaningful public policy efforts. Therefore, I encourage you to visit the ECS website which includes a list of science advocacy organizations and consider becoming more involved. Don’t just work to develop a technology that addresses the world’s challenges; push the economic and political boundaries to make that technology a deployed and impactful solution. To address the challenges that face us, we cannot just work hard, we must persevere. © The Electrochemical Society. DOI: 10.1149/2.002214IF

Eric D. Wachsman ECS President https://orcid.org/0000-0002-0667-1927

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Research highlight brought to you by

Metrohm Autolab

GREEN HYDROGEN GENERATION: A cross-disciplinary challenge rooted in electrochemistry Green hydrogen, produced from water electrolysis using renewable energy, is being explored as a strategy to reduce the dependence on fossil fuels and decarbonize chemical processes. From the environmental standpoint, this approach is extremely attractive given that mild conditions are used during electrolysis and there are no greenhouse gasses produced when using the hydrogen in a fuel cell. However, the economics of electrolysis and fuel cell systems for energy conversion relies heavily on the costs of electricity and metals like nickel, platinum, iridium, and titanium. Electrolyzer operating expenses must be minimized for green hydrogen to become an economically viable option. The electricity input contributes heavily to cost. Thus, decreasing the cost of renewable energy is necessary. Solar panels becoming more efficient and affordable within the past decades is cause for optimism in this regard1. However, there is much more that can be done to push forward the success of green hydrogen. More efficient electrolyzers could make better use of the input electricity and the development of cheaper and more durable components can reduce both the capital and operational costs. Electrolyzers are primarily electrochemical devices with electrocatalysts responsible for water splitting. The scientific challenges related to optimizing electrolyzers are attracting the attention of researchers that are not traditionally trained in electrochemistry. The search for efficient HER (Hydrogen Evolution Reaction) and OER (Oxygen Evolution Reaction) electrocatalysts piques the interest of inorganic chemists and physicists. Development of better membranes calls for expertise in organic and polymer chemistry. Optimization of catalysts inks and their interaction with substrates requires the know-how of a materials scientist. Heat and mass flow management within the stack and balance of plant are engineering endeavors. Clearly, the ongoing development of green hydrogen technologies has nucleated the collaboration of scientists and engineers across disciplines. The result is an influx of creativity and insight, as well as exciting new materials and techniques. Working in an unfamiliar domain means quickly getting up to speed with best practices and learning a new scientific vocabulary. For many institutions, education on 8

electrochemical principles and laboratory skills was not a key focus area until recent years. In some cases, the deficiency of fundamental electrochemical training has led to inconsistencies in the reporting of important performance indicators. The electrochemical community has taken note and called for a more rigorous approach. Experts have stepped up and provided practical guidance for quantifying and reporting in this domain. When investigating electrocatalyst materials it is necessary to have benchmarks and well-defined performance indicators. In 2013, a comprehensive benchmarking protocol for evaluating and reporting figures of merit for OER electrocatalysts was published. A JACS2 article provides practical advice on how to interpret the catalyst surface in terms of roughness and geometric surface area and how to perform and analyze measurements for valid comparisons of electrocatalytic performance. A common source of confusion and inconsistency in electrochemical measurements is the use of various reference electrodes (RE). Electrocatalytic activity is judged by the overpotential needed for a specified production rate (i.e. the current density for the HER or OER process). A three-electrode setup is needed to measure the potential and the RE is crucial for situating this potential on a relative scale, allowing comparison of measurements carried out by different groups and in various conditions. A 2020 Viewpoint article in ACS Energy Letters3 provides a detailed explanation of how to report the overpotential of an electrocatalyst, focusing on commonly-used reference electrodes like Hg/HgO, Hg/Hg2Cl2 (SCE), and Ag/AgCl. The reversible hydrogen electrode (RHE) is another commonly used RE that is extremely well-suited for HER and OER studies. A recent ACS Catalysis article 4 explains why the RHE is the ideal reference electrode for electrolysis research and explains how to prepare and work with an RHE. By convention, all standard redox potentials are reported versus the standard hydrogen electrode (SHE). The RHE is a pH-dependent extension of the SHE and refers to the reduction of a proton under non-standard conditions as described by the Nernst equation. Electrolyzers operate under both acidic and alkaline conditions, thus, the HER and OER are studied across the pH scale. The RHE is suitable for use at any pH and it shares the same dependency on pH as the HER and OER. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Research highlight brought to you by

Metrohm Autolab

Acidic Media:

Alkaline Media:

Hydrogen Evolution Reaction (HER)

2H+(aq) + 2e – ↔ H2(g)

2H2O(l) + 2e– ↔ H2(g) + 2OH–(aq)

Oxygen Evolution Reaction (OER)

H2O(l) ↔ 2H+(aq) + ½O2(g) + 2e–

2OH–(aq) ↔ H2O(l) + ½O2(g) + 2e–

Finding common language and understanding between fields is vital. A JOC 5 synopsis article clarifies electrochemical concepts for organic chemists. The article is highly visual, providing schematics that link concepts like free energy, redox potential, and overpotential. Equilibrium thermodynamics helps to provide a common point of reference that all chemists can relate to. Thermodynamic analysis is often applied to quantify the energy efficiency of electrolysis cells and stacks. A recent review article in the Journal of Power Sources6 highlights diverging definitions for the energy efficiency coefficient from academic and industrial literature. The article provides derivations in various conditions and reminds us that both electricity and heat must be accounted for in the analysis. The articles highlighted here represent a small fraction of the many resources available for building common understanding and better collaboration among all researchers working on the improvement of green hydrogen technologies. When the COVID pandemic shut down lab work and travel for many, the research community carried on with enthusiasm. Online seminars and working groups held openly and without cost have brought scientists together across disciplines and from around the world. For example, the Electrochemical Online Colloquium (https://www.electrochemicalcolloquium.com/) was started in 2021. This ongoing series of lectures addresses essential topics in electrochemistry by providing educational content alongside the personal perspective of expert speakers

The electrochemical community is acutely aware of the importance of transitioning to sustainable and climatesafe energy and chemical processes. Energy storage and conversion through green hydrogen is a promising strategy that requires scientific advancement to thrive. Thankfully, researchers from across disciplines are bringing their skills and creativity to this topic while the electrochemical community continues to drive collaborative efforts and share their core knowledge. References: 1. IRENA, Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5⁰C Climate Goal, International Renewable Energy Agency, 2020 Abu Dhabi. 2. McCrory, C. C. L.; Jung, S.; Peters, J. C.; Jaramillo, T. F. Benchmarking Heterogeneous Electrocatalysts for the Oxygen Evolution Reaction. J Am Chem Soc 2019, 135, 16977–16987. doi: 10.1021/ja407115p 3. Niu, S.; Li, S.; Du, Y.; Han, X.; Xu, P. How to Reliably Report the Overpotential of an Electrocatalyst. ACS Energy Letters 2020 5 (4), 1083-1087. doi: 10.1021/ acsenergylett.0c00321 4. Jerkiewicz, G. Standard and Reversible Hydrogen Electrodes: Theory, Design, Operation, and Applications. ACS Catalysis 2020 10 (15), 8409-8417. doi: 10.1021/acscatal.0c02046 5. Nutting, J. E.; Gerken, J. B.; Stamoulis, A. G.; Bruns, D. L.; Stahl, S. S. “How Should I Think about Voltage? What Is Overpotential?”: Establishing an Organic Chemistry Intuition for Electrochemistry. The Journal of Organic Chemistry Article ASAP. doi: 10.1021/acs.joc.1c01520 6. Lamy, C.; Millet, P. A critical review on the definitions used to calculate the energy efficiency coefficients of water electrolysis cells working under near ambient temperature conditions. J Power Sources 2020 447, 227350. doi. org/10.1016

metrohm.com/electrochemistry The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

30 Years

Pearls of

from The Electrochemical Society Journals

ELECTROCHEMICAL SCIENCE

BATTERIES AND ENERGY STORAGE • Optimized LiFePO4 for lithium battery cathodes, JES, 148, A224 (2001) • To be or not to be pseudocapacitive?, JES, 162, A5185 (2015) • Polysulfide shuttle study in the Li/S battery system, JES, 151, A1969 (2004) • Electrochemical characteristics and impedance spectroscopy studies of carbon-carbon supercapacitors, JES, 150, A292 (2005)

CORROSION SCIENCE AND TECHNOLOGY • Electrochemical characteristics of intermetallic phases in aluminum alloys - An experimental survey and discussion, JES, 152, B140 (2005) • An atomistic description of dealloying: Porosity evolution, the critical potential, and rate-limiting behavior, JES, 151, C614 (2004)

ELECTROCHEMICAL/ ELECTROLESS DEPOSITION • Superconformal electrodeposition of copper in 500–90 nm features, JES, 147, 4524 (2000) • Electrodeposition of copper in the SPS-PEG-Cl additive system - I. Kinetic measurements: Influence of SPS, JES, 151, C262 (2004)

ELECTROCHEMICAL ENGINEERING • Electrogeneration of hydroxyl radicals on boron-doped diamond electrodes, JES, 150, D79 (2003) • Oxidation of 4-chlorophenol at boron-doped diamond electrode for wastewater treatment, JES, 148, D60 (2001) 10

FUEL CELLS, ELECTROLYZERS, AND ENERGY CONVERSION • Hydrogen oxidation and evolution reaction kinetics on platinum: Acid vs alkaline electrolytes, JES, 157, B1529 (2010) • Computational fluid dynamics modeling of proton exchange membrane fuel cells, JES, 147, 4485 (2000)

ORGANIC AND BIOELECTROCHEMISTRY • Electropolymerized polyaniline nanocomposites from multiwalled carbon nanotubes with tuned surface functionalities for electrochemical energy storage, JES, 160, G3038 (2013) • Electrochemically exfoliated carbon quantum dots modified electrodes for detection of dopamine neurotransmitter, JES, 165, G3112 (2018)

PHYSICAL AND ANALYTICAL ELECTROCHEMISTRY, ELECTROCATALYSIS, AND PHOTOELECTROCHEMISTRY • Characterization of vulcan electrochemically oxidized under simulated PEM fuel cell conditions, JES, 151, E125 (2004) • Photoelectrochemical studies of oriented nanorod thin films of hematite, JES, 147, 2456 (2000)

SENSORS (ELECTROCHEMICAL) • An organ-like titanium carbide material (mxene) with multilayer structure encapsulating hemoglobin for a mediator-free biosensor, JES, 162, B16 (2015) • A pH electrode based on melt-oxidized iridium oxide, JES, 148, H29 (2001)

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

TOP

SOLID STATE SCIENCE

•

ELECTRONIC MATERIALS AND PROCESSING

CARBON NANOSTRUCTURES AND DEVICES • Solid-state electrochemistry of the Li single wall carbon nanotube system, JES, 147, 2845 (2000) • Photoresist-derived carbon for microelectromechanical systems and electrochemical applications, JES, 147, 277 (2000)

• Physics of copper in silicon, JES, 149, G21 (2002) • Germanium MOSFET devices: Advances in materials understanding, process development, and electrical performance, JES, 155, H552 (2008)

•

LUMINESCENCE AND DISPLAY MATERIALS, DEVICES, AND PROCESSING

DIELECTRIC SCIENCE AND MATERIALS

• Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor, JES, 154, G165 (2007) • Ferroelectric hafnium oxide based materials and devices: Assessment of current status and future prospects, JSS, 4, N30 (2015)

• Selecting conversion phosphors for white light-emitting diodes, JES, 158, R37 (2011) • Mechanism of persistent luminescence in Eu2+ and Dy3+ codoped aluminate and silicate compounds, JES, 152, H107 (2005)

•

ELECTRONIC AND PHOTONIC DEVICES AND SYSTEMS • Plastic-compatible low resistance printable gold nanoparticle conductors for flexible electronics, JES, 150, G412 (2003) • Formation of titania nanotubes and applications for dyesensitized solar cells, JES, 150, G488 (2003)

R FAC

• Sensor photoresponse of thin-film oxides of zinc and titanium to oxygen gas, JES, 147, 1592 (2000) • Review—organic-inorganic hybrid functional materials: An integrated platform for applied technologies, JES, 165, B3137 (2018)

To celebrate Interface’s 30th anniversary, we showcase 30 “pearls of the journals.” They are the two most highly cited papers in each of the 14 topical areas published in JES and JSS in the last 30 years. Because this gave us 28 papers, we then rounded up to 30 by including the two next-most-cited papers (giving us one for each year of Interface’s existence), both of which happened to be in OF the battery topical area.

SENSORS (SOLID STATE)

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

CA NDIDAT ES FOR SOCIE T Y OFFICE Biographical sketches and candidacy statements of the nominated candidates for the annual election of ECS officers.

Candidates for Third Vice President

Turgut Gür is Adjunct Professor of Materials Science and Engineering at Stanford University; Visiting Professor at the Chinese University of Mining and Technology-Beijing; and International Mentor at the Norwegian University of Science and Technology. After more than three decades, he retired recently from Stanford where he also led three major on-campus multidisciplinary team- and theme-based research centers focused on energy and advanced materials. A recognized leader in high temperature electrochemical energy research, materials, and technologies, Prof. Gür is a Fellow of The Electrochemical Society with 11 U.S. patents and 160+ publications. He completed his BS and MS in Chemical Engineering at the Middle East Technical University and three graduate degrees including a PhD in Materials Science and Engineering at Stanford. An active ECS member since 1973, Prof. Gür held Society leadership positions including chairing the High-Temperature Energy, Materials, & Processes (H-TEMP) division; serving on ECS Advisory Boards, Committees, and the Board of Directors and Executive Committee; co-organizing 17 Society symposia; and co-editing the corresponding ECS Transactions volumes. Prof. Gür was on the board of the International Society for Solid State Ionics for three separate terms over 10 years, and Associate Editor of the Journal of the American Ceramic Society for 12 years.

Doron Aurbach is a professor in the Department of Chemistry at BarIlan University (BIU) and Director of the Energy & Sustainability Center. He supervised 65 PhD and 80 MS students; founded the BIU electrochemistry group (1985); and chaired the Chemistry Department (2001– 2005) and Israel National Labs Accreditation Authority (2010–2016). He heads INREP (Israeli National Research Center for Electrochemical Propulsion), which brings 25 research groups and seven Israeli universities together to work on transportation power sources. Aurbach’s group develops new battery systems for electro-mobility and large energy storage for sustainable energy and water purification, desalination, and disinfection technologies, and collaborates with leading international industries including Nichia, cATL, BASF, and GM. They are establishing the basic scientific background for practical achievements including in situ spectro-electrochemical methodologies; studies of non-aqueous electrochemical systems; new solution chemistries; and understanding the correlation among electrochemical response, structure, morphology, and surface chemistry of useful electrode materials. The author of more than 730 peerreviewed papers with nearly 80,000 citations and an h-index of 137 (October 21, 2021), Prof. Aurbach serves as Technical Editor for the Journal of The Electrochemical Society Batteries and Energy Storage technical area. A Fellow of The Electrochemical Society, Materials Research Society, and International Society of Electrochemistry, he received the 2020 Israel Chemical Society Gold Medal; 2018 Eric and Sheila Samson Prime Minister’s Prize for Innovation in Alternative Fuels for Transportation; 2018 ISE Alexander Frumkin Medal; 2014 IBA Yeager Award; and ECS Allen J. Bard Award (2017), Battery Division Research Award (2013), and Technology Award (2005).

James M. Fenton is Director of the University of Central Florida’s FSEC Energy Research Center and Professor of Materials Science and Engineering. He leads 50+ faculty and staff researching, developing, and evaluating clean energy technologies, and educating the current and future workforce about technology innovations in solar energy, high performance buildings, alternative transportation, advanced energy systems, STEM education and workforce training, and energy policy research. Prof. Fenton attended his first ECS meeting as a student in 1982. During his 40 years of ECS membership, Prof. Fenton was ECS Secretary (2017–2021); chaired the search committee that hired Christopher Jannuzzi; held all ECS Boston Section (now the ECS New England Section) and IE&EE Division offices; and served as a member of the Executive Committee, Board of Directors, Council of Local Sections, Individual Membership, Finance, New Technology, Publication, Education, Ethical Standards, Technical Affairs, and Ways and Means Committees, and Interdisciplinary Science & Technology Subcommittee. Prof. Fenton chaired the ECS student poster sessions for four years, and Polymer Electrolyte Fuel Cells Student Poster Session competition since its inception in 2011. He is a Fellow of The Electrochemical Society and received the 2014 ECS Energy Technology Division Research Award.

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Statement of Candidacy

Increasing trends in climate change and global warming which present an existential challenge to Earth’s ecosystems are intimately linked to our thirst for energy and electricity provided primarily by fossil fuels. The 2021 United Nations Climate Change Conference demonstrated the difficulty in achieving agreement to tackle these complex issues. However, clean water and air and a healthy environment are critical for us all. Most of ECS members’ scientific activities involve charge separation and recombination phenomena at interfaces and junctions which are central to clean water, environment, (continued on next page)

Photo: Nick Waters

Candidate for President

Statement of Candidacy

I am honored to be a candidate for ECS Vice President. If elected, I look forward to serving our “member-driven” society of world-class researchers from industry, academia, and government. In 2017, when I began my term as ECS Secretary, many of us communicated with each other through meetings and high-quality journal publications. In 2020, the COVID-19 pandemic caused uncertainty in hosting live meetings, and declining membership and industrial participation. By holding the 2020 PRiME Meeting, 239th ECS Meeting, and 240th ECS Meeting digitally, ECS made free attendance and engagement possible

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Candidates for Treasurer

Turgut Gür

Elizabeth (Lisa) J. Podlaha-Murphy is Department Chair of the Chemical and Biomolecular Engineering Department at Clarkson University. Her research focuses on the electrodeposition of novel alloy and composite materials for various applications, including water splitting for hydrogen generation; corrosion resistant surface coatings; nanostructured materials for micro and nanodevice components; and modeling battery and electrochemical systems. After completing her BS in Chemical Engineering at the University of Connecticut (1986), Dr. Podlaha worked at IBM, then earned a PhD in Chemical Engineering from Columbia University, followed by a postdoc in the Department of Materials Science at the École Polytechnique Fédérale de Lausanne. She joined Louisiana State University as an Assistant/tenured Associate Professor in Chemical Engineering (1998–2007), then Northeastern University as a tenured Associate/full Professor (2007–2017). As part of NSF-, DOE-, NIH-, and DARPA-funded projects (including the NSF CAREER Award), Dr. Podlaha directed 20 PhD, six MS, and 40+ undergraduate students in electrochemical research. She authored or co-authored 84 peer-reviewed journal publications (half in the Journal of The Electrochemical Society and ECS Electrochemical and Solid-State Letters); 24 proceedings papers; one book chapter; and four patents. She chaired the ECS Electrodeposition Division from 2015– 2017 after being Member at Large, Treasurer, Secretary, and Vice Chair. Dr. Podlaha has served on many Society committees, including Membership; and has organized, chaired, and co-chaired symposia. In 2019, she co-advised the newly formed ECS Clarkson University Student Chapter.

Nianqiang (Nick) Wu is the Armstrong-Siadat Endowed Professor in Materials Science at the University of Massachusetts (UMass) Amherst. His research focuses on the materials science areas of biosensing and photodynamic therapy (precision medicine); photocatalysts and photoelectrochemical cells for environmental and energy sustainability; and electrochemical energy storage. He completed his PhD in Materials Science & Engineering at Zhejiang University followed by a postdoc at the University of Pittsburgh (1999–2001); directed the Keck Surface Science Center at Northwestern University (2001–2005); was promoted Berry Chair of Engineering at West Virginia University; and joined UMass Amherst in 2020. A Fellow of The Electrochemical Society and Royal Society of Chemistry, Dr. Wu has received numerous important awards, including the ECS Sensor Division Outstanding Achievement Award. He holds editorial positions with international journals and has authored or co-authored 195 journal articles, three book chapters, and Biosensors Based on Nanomaterials and Nanodevices. A Clarivate Analytics Highly Cited Researcher, his papers have been cited 25,000+ times with an h-index of 72. Dr. Wu has served ECS in many capacities on committees and subcommittees; he has held all the ECS Sensor Division officer positions; chaired the ECS Fellows Election and Henry Linford Award Subcommittees; and been an Interface Advisory Board member; Guest Editor for Journal of The Electrochemical Society and Interface; lead organizer for the Symposium on Photocatalysis and Solar Fuels, ad hoc Symposia on Biosensors and Point-of-Care Testing Devices; and Session Chair for ECS meeting symposia.

Statement of Candidacy

(continued from previous page)

and energy production, conversion, and storage. We are ideally positioned to exploit this unique leverage and advance clean technologies to meet global demand while curbing global warming. If elected, I will lead ECS to serve as the global hub for science and discovery that contributes to sustainable solutions for global challenges by engaging members in cross-disciplinary activities; communicating members’ groundbreaking discoveries to the public; collaborating with international counterparts; and creating opportunities for global industry leaders and policymakers to join our biannual meetings and bridge the gap between science, policy, and technology. We must also educate and train the public through our expert members’ webinars and short courses. As an international society, ECS needs to be more engaged with our worldwide community and explore programs that benefit all. Global challenges can only be resolved by international collaboration on complex problems. While continuing to provide an intellectually stimulating and scientifically vibrant home to over 8,000 dedicated members from more than 85 countries, we must also invest heavily in students and young scientists to prepare them for leadership in their fields and our Society. I will help generate resources for young scientists to attend ECS meetings, and increase membership among young scientists by expanding national and international student chapters. ECS has been a home and integral part of my professional life since 1973. I have always valued ECS meetings’ stimulating and informative environment, and felt fortunate to build many treasured and lasting friendships. It is an honor to be considered for this prestigious position to further serve you and our esteemed Society. Doron Aurbach (continued from previous page)

As an ECS member since 1987, I have had the good fortune to witness the global rise of electrochemical and solid state science and technology. ECS has been at the forefront of providing leading science and engineering content in timely electrochemical and solid state topics, and providing venues for sharing ideas and networking, often from the roots up as represented by the many ECS divisions. The Society should be the go-to premier resource for current and future members, and non-members. As we emerge from

It is my great honor to be a candidate for ECS Treasurer, responsible for ensuring continued growth through the sustainable increase of assets; efficient use of financial resources; and allocation of resources to support activities that advance the mission and retain the Society’s sustainability and dynamics. Membership is ECS’s most important part. It is essential to recruit new members, retain existing members, and continue serving members’ professional needs and interests. The Society must champion

An active ECS member since 1983, I have participated in dozens of ECS meetings and contributed to the electrochemistry community by pioneering several fields connected to energy storage and conversion. I have educated more than 200 senior scientists in the field of electrochemical science, many holding senior positions in academic institutions and industries today. As Associate Editor for Electrochemical and Solid-State Letters (2003–2012), I

(continued on next page)

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Statement of Candidacy

CAFOR NDIDAT ES T FOR SOCIE (continue T Y OFFICE CA NDIDAT ES SOCIE Y OFFICE d) Doron Aurbach (continued from previous page)

supported quick and prompt publications. I became an Associate Editor for the Journal of The Electrochemical Society in 2011 and since 2015 have served as Technical Editor for Batteries and Energy Storage (BES), handling—with excellent and dedicated associate editors—almost 1000 papers annually. We maintain JES as a leading electrochemical journal and elevate its scientific level while supporting young scientists with strict but educational and helpful feedback. Having collaborated intensively with global research groups— and important industries—I have an excellent electrochemistry network. I founded and lead INREP which brings together research groups and Israeli universities to collaborate rather than compete. If elected, I will do my best to bring this spirit of collaboration to increasing collaboration and information flow in our community. We face immense global challenges related to energy policies and economies. We suffer from dangerous and disastrous climate changes that demand investing great efforts in sustainability, the massive use of renewable energies, and developing new technologies for large energy storage and conversion. Electrochemistry is at the forefront of the necessary global efforts. My mission will be to unify efforts toward developing better energy technologies, promoting young scientists, and establishing stronger collaborative relationships among national scientific communities as gateways to peace. James M. Fenton (continued from page 12)

for a broader audience, and attracted more participants than in-person meetings. PRiME had the highest registration in ECS history with 1,200 student presenters from around the world. Now we communicate research through digital and in-person hybrid meetings, social networking sites, open access journal articles, videos, webinars, and podcasts. Through these communication platforms, ECS members will inspire future members

(pre-college, undergraduate, and graduate students) to choose careers in electrochemical and solid state research. With our help, this future workforce will develop technologies that tackle problems related to energy, health, education, the environment, national security, global development, and climate change. ECS is uniquely positioned to mitigate climate change—which many consider a larger crisis than the pandemic—through rapid decarbonization by direct and indirect electrification of energy producing and manufacturing processes, limiting the longterm increase in average global temperatures to 1.5o C by 2050. To promote awareness of electrochemical and solid state scientific developments at the precollege level, I will encourage divisions, sections, student chapters, and corporate members to provide educational tools for K–12 teachers. By disseminating ECS members’ research to the general public, they too can be active in mitigating climate change. As ECS Vice President, I will work cooperatively with you, the officers, and our outstanding professional staff to define and implement new visions and initiatives enabling current and future members to solve global grand challenges. Elizabeth (Lisa) J. Podlaha-Murphy (continued from previous page)

the pandemic and scientists and engineers around the world embrace an online working environment, open access and Free the Science are ever more relevant. A lesson learned is that information access is no longer constrained by physical means. The following are important to continue this growth: enhancing membership and meeting and webinar participation; increasing quality research submissions in ECS publications; furthering outreach activities; and expanding awareness of ECS offerings. I look forward to the challenge of balancing a budget that directs these activities and enhances the Society’s reputation. My journey with the Society started as a graduate student when I received the 1991 Battery Division Student Research Award. My research has moved in the direction of electrodeposition, providing myriad opportunities to examine different

applications enabled by electrodeposition. This background has helped shape my knowledge of electrochemical science and engineering in a broader direction. With this perspective, I am well suited to joining the Society’s leadership team with a holistic view. I have experience in budget management and planning in my current role as department chair at a research university. I value candid, clear, and consistent communications for the seamless and healthy operation of the Treasurer position. As your ECS Treasurer, I will earnestly work toward building a solid and enduring future for the Society. Nianqiang (Nick) Wu (continued from previous page)

Diversity, Equity, and Inclusion, actively recruit underrepresented groups, and recruit more international members, thus attracting the workforce to tackle grand global challenges in climate change, food and energy sustainability, and public health crises like the COVID-19 pandemic. We can increase financial support for student members to facilitate new student chapters; assist student chapter operation; and provide ECS meeting travel grants. Establishing more awards recognizes members’ career accomplishments, outstanding service, and leadership. Allocating resources to ECS division symposia promotes attendees’ interaction and engagement with the Society. We can encourage society-level interdisciplinary symposia emphasizing global challenges, and co-sponsor other organizations’ international meetings focusing on these issues. We can explore holding ECS biannual meetings in more regions to recruit new international members and enhance the Society’s global impact. The ECS leadership team must financially support publication initiatives, including Free the Science which makes open access articles accessible to the general public, and new journals that reflect the evolution of the electrochemical and solid state research fields. If elected, I will work with ECS leadership, staff, and members to contribute to the Society's activities and to serve all of you.

For extended versions of the candidate biographies and statements, please see the ECS blog. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org www.electrochem.org/ecs-blog/2022-candidates

Highlights of the 240th ECS Meeting by Frances Chaves

DIGITAL MEETING October 10-14, 2021

rom October 10 to 14, 2021, the online 240th ECS Meeting had 4,075 participants from 41 countries around the world. This included 2,731 digital participants and 1,344 digital presenters—with 645 of the presenters being students. A total of 1,906 abstracts were accepted for the meeting, of which 997 were from students (742 oral; 255 posters). Presenters and participants engaged and exchanged ideas in 122 sessions convened in 43 symposia. Participants selected from among 1,931 digital presentation files including 1,012 videos, 810 slide decks, and 110 posters. There were 344 invited talks and 25 award and/or keynote addresses.

ECS Opening Ceremony

ECS Awards and Recognition Highlights Three ECS Society award addresses were given during the digital meeting. The ECS Carl Wagner Memorial Award was presented to Yushan Yan of the University of Delaware. The award was established in 1980 to recognize mid-career achievement; excellence in research areas of interest to the Society; and significant contributions in the teaching or guidance of students or colleagues in education, industry, or government. In his award address, “Toward Platinum-free Fuel Cells for Affordable Zero-emission Vehicles,” Yan discussed recent work on hydroxide exchange membrane fuel cells (HEMFCs) and presented a roadmap developed for this technology, the progress made in developing one of the most stable membranes, and some of the most active nonprecious metal catalysts. Yan addressed the fundamental question: Why are hydrogen oxidation reactions slower in base than in acid for precious metal catalysts?

ECS Plenary Lecture Jannuzzi introduced the speaker delivering the 240th ECS Meeting Lecture, a highlight of the ECS Plenary Session. Michael Hecht, Associate Director for Research Management at the MIT Haystack Observatory, delivered the 240th ECS Meeting Lecture. In “Electrolysis on Mars: MOXIE and the Perseverance Mission,” Hecht, who is Principal Investigator of the Mars Oxygen ISRU Experiment (MOXIE) now operating on Mars as a payload on NASA’s Perseverance rover, described the first demonstration of oxygen production on the surface of another planet. MOXIE is a prototype of a system that will someday provide many tons of oxygen as the primary component (by mass) of the propellant for a Mars Ascent Vehicle that will return astronauts from the Red Planet. (continued on next page) The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

240TH ECS MEETING • October 10-14, 2021

The ECS opening ceremony launched the online meeting. Introductory remarks were given by Christopher Jannuzzi, ECS CEO and Executive Director, who welcomed event participants and provided an overview of the week ahead. Januzzi thanked the symposia sponsors and exhibitors as well as meeting participants, volunteers, and staff. Eric Wachsman, ECS President, took the digital floor and described how the job of scientists and engineers is to push the boundaries of discovery and advance the technologies that benefit humankind. As a scientific society, it is ECS’s duty to not only disseminate this knowledge, but to advocate for the best use of this knowledge including influencing governmental policies and fighting misinformation. Wachsman thanked former ECS Presidents Christina Bock (2019–2020) and Stefan De Gendt (2020–2021) for stewarding the Society through the challenges posed by the pandemic.

(continued from previous page)

Gerald E. Frankel of Ohio State University received the Olin Palladium Award which was established in 1950 for distinguished contributions to the field of electrochemical or corrosion science. His award address, “Pitting Corrosion Retrospective,” summarized different studies that provided insights into pitting corrosion. He described how the analysis of metastable pits has illuminated pit growth kinetics and the conditions for pit stability; how so-called 2D pitting clarified the behavior of very small pits; and how artificial pit electrodes or 1D pits provided insight into the behavior of deeper pits. Frankel illustrated the use of scanning Kelvin probe force microscopy for visualization of the microstructural heterogeneities that drive pitting corrosion and other forms of localized corrosion.

Ernesto Julio Calvo, Universidad de Buenos Aires Douglas Hansen, University of Dayton Research Institute Jihyun Kim, Korea University Jagjit Nanda, Oak Ridge National Laboratory Rosa Palacin, Institute of Materials Science of Barcelona Slava Rotkin, Pennsylvania State University Xiao-Dong Zhou, University of Louisiana at Lafayette The Norman Hackerman Young Author Award was presented to Stefan Oswald of the Technische Universität München. The Bruce Deal & Andy Grove Young Author Award was presented to: Tingyu Bai, University of California, Los Angeles Nicholas Hines, Georgia Institute of Technology Yekan Wang, University of California, Los Angeles The ECS Toyota Young Investigator Fellowship recipients were announced. Chibueze Amanchukwu, University of Chicago Christopher G. Arges, Pennsylvania State University Marm Dixit, Oak Ridge National Laboratory Marta Hatzell, Georgia Institute of Technology Siddharth Komini Babu, Los Alamos National Laboratory

240TH ECS MEETING • October 10-14, 2021

Over the course of the 240th ECS Meeting, 15 division awards were given. • Esther S. Takeuchi of Stony Brook University delivered the ECS Edward Goodrich Acheson Award Address, “Investigation of Batteries over Multiple and Length and Time Scales.” The Acheson Award was established in 1928 to recognize distinguished contributions to the advancement of any of the objects, purposes, or activities of The Electrochemical Society. Takeuchi explained how the advent of in situ and operando approaches over multiple length scales provides the ability to gain insight into dynamic electrochemical processes and failure mechanisms of energy storage systems. Further, probes of systems under both spatial and time dimensions over several orders of magnitude are yielding unprecedented information regarding the mechanistic details. Takeuchi provided examples of recent in situ and operando results and comments on future directions for gaining full insight into batteries as guidance for future innovation.

• • •

•

• • • • •

The Awards and Recognition Ceremony celebrated the achievements of today’s greatest researchers in electrochemstry and solid state science. Winners of the 240th Z01 General Student Poster Session Awards, as well as ECS Society, Division, and Chapter Awards, ECS Toyota Fellowships, Leadership Circle Awards, and more were recognized. The following were named to the 2021 Class of Fellows of The Electrochemical Society: Shekhar Bhansali, Florida International University Anja Boisen, Technical University of Denmark Stanko Brankovic, University of Houston 16

•

The Battery Division Early Career Award Sponsored by Neware Technology Limited was presented to Betar Gallant, Massachusetts Institute of Technology. The Battery Division Technology Award was presented to Arumugam Manthiram, University of Texas at Austin. The Battery Division Research Award was presented to Chunsheng Wang, University of Maryland. The Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation was presented to: - Lin Ma, United States Army Research Laboratory. - Wei Sun, Westfälische Wilhelms-Universität Münster. The Battery Division Student Research Award Sponsored by Mercedes-Benz Research & Development was presented to: - Muhammad Mominur Rahman, Virginia Polytechnic Institute and State University. - Yang Yu, Massachusetts Institute of Technology. The Corrosion Division Morris Cohen Graduate Student Award was presented to Thalia Standish, Western University. The Electrodeposition Division Research Award was presented to Noam Eliaz, Tel Aviv University. The Electrodeposition Division Early Career Investigator Award was presented to Jingxu Zheng, Cornell University. The High-Temperature Energy, Materials, & Processes Division Subhash Singhal Award was presented to Nguyen Minh, University of California, San Diego. The Industrial Electrochemistry and Electrochemical Engineering Division New Electrochemical Technology (NET) Award was presented to: - Faraday Technology, Inc. - Urban Electric Power. The Sensor Division Outstanding Achievement Award was presented to: - Marc Madou, University of California, Irvine. - Yasuhiro Shimizu, Nagasaki University.

The following section award was given. •

The Pacific Northwest Section Electrochemistry Research Award was presented to Wei Wang, Pacific Northwest National Laboratory.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Z01 ECS General Student Poster Session Students submitted 79 posters to the 240th ECS Meeting Z01 General Student Poster Session. The judges reviewed the digital presentations and chose the following for awards. (Only corresponding authors are listed here.) 1st Prize - $1,500 Cash Sara Sheffels, Massachusetts Institute of Technology Z01-1955 - “Proton Transport in Hydrated GdOx Measured with GdCo Magnetic Sensing Layer” 2nd Prize - $1,000 Cash Andrew May, The City College of New York Z01-1710 - “Comparison between Experimental Results and Models for Electrochemical Hydrogenation and Hydrogenolysis of Furfural on Cu in Acidic Media” 3rd Prize - $500 Cash Xiujuan Chen, West Virginia University Z01-1682 - “Electrochemical Activation to Unlock the Potential of Manganese Sulfide As High-Performance Cathodes for Rechargeable Aqueous Zn-Ion Batteries”

ECS Live Topical Sessions

ECS hosted 122 live topical sessions which transplanted on-site session rooms into an online environment. Sessions occurred twice daily throughout the meeting, featuring live presentations, question and answer opportunities, topical discussions, and more.

Symposia Sponsors and Exhibitors Special thanks to the meeting symposia sponsors and exhibitors, whose support and participation directly contributed to the success of the meeting. Thank you for developing the tools and equipment driving scientific advancement, sharing your innovations with the electrochemical and solid state communities, and providing generous support for the 240th ECS Meeting. Meeting exhibitors displayed their products and services in the Digital Exhibitor and Vendor Guide (DEVguide). Viewers scan the latest electrochemistry and solid state science products with ease as the DEVguide navigates seamlessly on any platform.

240th ECS Meeting Symposia Sponsors

GOLD SPONSOR

Congratulations to all of the award recipients!

Alice Suroviec, Berry College Lok-Kun Tsui, University of New Mexico Trisha Andrew, University of Massachusetts Amherst Xiaolin Li, Pacific Northwest National Laboratory Roseanne Warren, University of Utah Hiroshi Imahori, Kyoto University William Tarpeh, Stanford University Gautam Banerjee, Micron Technology Inc. Christopher Arges, Pennsylvania State University Dmitrij Zagidulin, Western University Andrew Hillier, Iowa State University

Polymer Electrolyte Fuel Cells & Electrolyzers 2021 Symposium Student Poster Award

At every meeting, ECS presents several awards generously funded by individual symposium sponsors. Thank you to the Office of Naval Research and the Army Research Office for their generous sponsorship of this symposium. Congratulations to the winners of the 240th ECS Meeting Polymer Electrolyte Fuel Cells & Electrolyzers (PEFC&E) symposia–funded best poster and presentation awards! (Corresponding authors are listed with the awards.) 1st Prize - $1,200 Yoshihiro Chida, Graduate School on Environmental Studies, Tohoku University I01D-1158 - “Oxygen Reduction Reaction Properties and Microstructure of Pt/Nb:SnO2 Model Catalysts Fabricated on Pt Single Crystal Surfaces” 2nd Prize - $800 Kenta Hayashi, Graduate School of Environmental Studies, Tohoku University I01D-1159 - “Hydrogen Peroxide Generation and Hydrogen Oxidation Reaction Properties of Pt/Ir(111) and Ir/Pt(111) Bimetallic Surfaces” 3rd Prize - $400 Rikki Tanaka, Graduate School of Engineering, Tohoku University I01C-1117 - “Molecular Dynamics Study of Proton Conductivity at an Interface between Nafion and Graphene Sheet”

Office of Naval Research for I01

National Science Foundation for M02

SILVER SPONSOR

Army Research Office for I01

Gelest for G01

TEL for G01

Lam Research Corporation for D03

Umicore for A02

BRONZE SPONSOR Applied Materials for G01

Taiyo Nippon Sanso for H03

ASM for G01

CONTRIBUTING SPONSOR Mattson Technology for G01

Air Liquide for G01

240th ECS Meeting – Exhibitors

BioLogic USA

ECS

Gamry

Ion Power

research

Pine Research

Scribner Associates

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SemiLab 17

240TH ECS MEETING • October 10-14, 2021

ECS thanks the following individuals who served as judges for the 240th ECS Meeting Z01 General Student Poster Session:

SOCIETY NEWS

Publications Update Journal of The Electrochemical Society ECS welcomes Olga Marina of Pacific Northwest National Laboratory to the publications family as Associate Editor, handling manuscripts for the JES Fuel Cells, Electrolyzers, and Energy Conversion technical interest area. The ECS Publications Subcommittee appointed Dr. Marina to a one-year term ending on May 19, 2023. On May 23, 2021, the ECS Publications Subcommittee voted to extend for an additional three years the term of Thomas J. Schmidt of the Paul Scherrer Institute as Associate Editor. Dr. Schmidt continues handling manuscripts for the JES Fuel Cells, Electrolyzers, and Energy Conversion technical interest area until October 31, 2024.

New Gold Open Access Journals In the spirit and mission of Free the Science, in 2022 ECS will begin accepting submissions to ECS Advances and ECS Sensors Plus, our first-ever Gold Open Access Journals. ECS Advances will publish full-length original work, brief communicationstyle papers, perspectives, review articles, and special issues to provide Coming Soon! The a multidisciplinary open access forum Electrochemical Society is for publishing peer-reviewed content going for gold! covering all technical areas supported by the Society. ECS Sensors Plus, a one-stop-shop journal for sensors, aims to advance the fundamental science and understanding of sensors and detection technologies for efficient monitoring and control of industrial processes and the environment, and the betterment of quality of life and human health. ECS Sensors Plus will publish fulllength original work, brief communication-style papers, perspectives, review articles, and special issues.

ECS Journal of Solid State Science and Technology Editor-in-Chief Krishnan Rajeshwar and the ECS Publications team express their deepest thanks and appreciation to Jennifer Bardwell for her nine-and-a-half years of service to JSS as the Technical Editor of the Electronic Materials and Processing technical interest area. As the inaugural technical editor when JSS was launched in 2011, Dr. Bardwell was instrumental in building the strong foundation and trajectory of growth that JSS continues to celebrate today. Dr. Bardwell will surely be missed by the ECS Publications team and the authors she served. On August 23, 2021, the ECS Publication Subcommittee voted to continue the term of Kailash C. Mishra as Technical Editor of Luminescence and Display Materials, Devices, and Processing for an additional one-year term. Dr. Mishra continues in his role of ensuring the quality of content published in JSS until his term ends on December 31, 2022. On August 23, 2021, the ECS Publication Subcommittee voted to continue for an additional one-year term, Fan Ren of the University of Florida as Technical Editor of Luminescence and Display Materials, Devices, and Processing. Dr. Ren continues in the role of ensuring the quality of content published in JSS until his term ends on September 30, 2024.

We are a family! The ECS Journal Family; growing to Connect, Empower, Accelerate innovation, Engage the community, and Champion the dissemination of research.

LEARN MORE 18

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

ECS Journals Current and Upcoming Focus Issues Journal of The Electrochemical Society (JES)

READ ONLINE Recent Advances in Chemical and Biological Sensors & MicroNanofabricated Sensors and Systems Technical Editor: Ajit Khosla Guest Editors: Michael Adachi, Netz Arroyo, Thomas Thundat

Future of Intercalation Chemistry for Energy Storage and Conversion in Honor of M. Stanley Whittingham

Technical Editor: Doron Aurbach Guest Editors: Brett Lucht, Louis Piper, Y. Shirley Meng

NOW IN PRODUCTION

Solid Oxide Fuel Cells (SOFCs) and Electrolysis Cells (SOECs) Technical Editor: Xiao-Dong Zhou Guest Editors: Eric Wachsman, Subash Singhal

Modern Electroanalytical Research in the Society for Electroanalytical Chemistry (SEAC) Technical Editor: David E. Cliffel Guest Editors: Lane Baker, Lanqun Mao, Frank Zamborini, Bo Zhang

Energy Storage Research in China

Technical Editor: Doron Aurbach Guest Editors: Hong Li, Yi-Chun Lu, Kai Jiang, Haijun Yu, Kothandaraman Ramanujam, Chunmei Ban, Venkataraman Thangadurai

Women in Electrochemistry Technical Editor: Ajit Khosla

18th International Meeting on Chemical Sensors (IMCS 18) - Volume Two

Technical Editor: Ajit Khosla Guest Editors: Peter Hesketh, Steve Semancik, Udo Weimar, Yasuhiro Shimizu, Joseph Stetter, Gary Hunter, Joseph Wang, Xiangqun Zeng, Sheikh Akbar, Muthukumaran Packirisamy, Rudra Pratap

ACCEPTING SUBMISSIONS Advanced Electrolysis for Renewable Energy Storage

Technical Editor: Xiao-DongZhou Guest Editors: Hui Xu, Bryan Pivovar, Grigorii Soloveichik Deadline: January 9, 2022

Biosensors and Nanoscale Measurements: In Honor of Nongjian Tao and Stuart Lindsay

Technical Editor: Ajit Khosla Guest Editors: Larry Nagahara, Erica Forzani, Huixin He, Jin He, Tianwei Jing, Jessica Koehne, Chenzhong Li, Patrick Oden, Shaopeng Wang, Nick Wu, Bingqian Xu, Peiming Zhang Deadline: January 5, 2022

Electrochemical Separations and Sustainability

Technical Editor: John Harb Associate Editor: John Staser Guest Editors: Hui Xu, Gerri Botte, Gang Wu, Christopher Arges, Xiao Su Deadline: February 3, 2022

UPCOMING Nucleation and Growth: Measurements, Processes, and Materials Technical Editor: Takayuki Homma Guest Editors: Tom Moffat, Yasuhiro Fukunaka, Y. Shirley Meng, Timo Jacob, Toshiyuki Nohira Submissions Open: March 31, 2022 Deadline: June 29, 2022

Heterogeneous Functional Materials for Energy Conversion and Storage II

Technical Editors: Doron Aurbach, David E. Cliffel, Xiao-Dong Zhou Guest Editors: Wilson Chiu, Fanglin Chen, Steven DeCaluwe, Nian Liu, Alice Suroviec Submissions Open: June 30, 2022 Deadline: September 28, 2022

Multiscale Modeling, Simulation and Design: In Honor of Ralph E. White

Technical Editor: John Harb Guest Editors: Venkat Subramanian, Gerardine Botte, Trung Nguyen Submissions Open: November 3, 2022 Deadline: February 1, 2023 220

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

ECS Journals Current and Upcoming Focus Issues ECS Journal of Solid State Science and Technology (JSS)

READ ONLINE

NOW IN PRODUCTION

Solid State Electronic Devices and Materials

Dedicated to the Memory of George Blasse: Recent Developments in Theory, Materials, and Applications of Luminescence

Technical Editor: Fan Ren Guest Editors: Chao-Sung Lai, Chia-Ming Yang, Yu-Lin Wang

(ICONN-2021)

Selected Papers from the International Conference on Nanoscience and Nanotechnology 2021

Technical Editor: Kailash Mishra Guest Editors: John Collins, Jakoah Brgoch, Ron-Jun Xie, Eugeniusz Zych, Tetsuhiko Isobe, Ramchandra Pode, Andries Meijerink

Technical Editor: Francis D’Souza Guest Editors: Senthil Kumar Eswaran, S. Yuvaraj, M. S. Ramachandra Rao, Masaru Shimomura

ACCEPTING SUBMISSIONS Molecular Electronics Including Selected Papers from the 10th International Conference on Molecular Electronics Editor-in-Chief: Krishnan Rajeshwar Guest Editors: Jean Christophe Lacroix, Christophe Bucher, Richard McCreery Deadline: January 19, 2022

Advanced Energy, Electronic, and Dielectric Materials: Fabrication, Characterization, Properties, and Applications

IUMRS-ICA 2021

Technical Editor: Fan Ren Guest Editors: In-Hwan Lee, Alexander Polyakov, Sang-Woo Kim, Hyunhyub Ko, Chunjoong Kim Deadline: February 23, 2022

Emerging Trends in CMP

Technical Editor: Aniruddh Khanna Guest Editors: Duane Boning, Pradeep Veera, Knut Gottfried, Abhudaya Mishra, Veera Raghava Kakireddy, Jingoo Park, Jichul Yang, Gowrisankar Damarla, Taesung Kim, Xinchun Lu, Arthur Chen, Bahar Basim Deadline: March 2, 2022

Technical Editor: Peter Mascher Guest Editors: Kiran Mangalampalli, Eswaraiah Varrla, Yuvraj Sivalingam, Debabrata Sarkar Deadline: January 26, 2022

UPCOMING Selected Papers from the International Electron Devices and Materials Symposium 2021 (IEDMS 2021) Technical Editor: Fan Ren Guest Editors: Wei-Chou Hsu, Yon-Hua Tzeng, Shoou-Jinn Chang, Meng-Hsueh Chiang, Sheng-Po Chang Submissions Open: January 20, 2022 Deadline: April 20, 2022

VISIT

www.electrochem.org/submit

www.electrochem.org/focusissues

• JES manuscript submissions • JSS manuscript submissions

• Calls for upcoming JES and JSS focus issue papers • Links to published issues • Future focus issue proposals

www.electrochem.org/focusissues www.electrochem.org The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

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SOCIETY NEWS

2021-2022 ECS Committees Executive Committee of the Board of Directors

Eric Wachsman, Chair........................................................................................President, Spring 2022 Turgut Gür.......................................................................................Senior Vice President, Spring 2023 Gerardine Botte............................................................................. Second Vice President, Spring 2024 Colm O’Dwyer...................................................................................Third Vice President, Spring 2025 Marca Doeff.......................................................................................................Secretary, Spring 2024 Gessie Brisard ...................................................................................................Treasurer, Spring 2022 Christopher Jannuzzi................................................................................... Term as Executive Director

Audit Committee

Stefan De Gendt, Chair..............................................................Immediate Past President, Spring 2022 Eric Wachsman..................................................................................................President, Spring 2022 Turgut Gür.......................................................................................Senior Vice President, Spring 2022 Gessie Brisard.................................................................................................... Treasurer, Spring 2022 Robert Micek..................................................................Nonprofit Financial Professional, Spring 2022

Education Committee

Alice Suroviec, Chair......................................................................................................... Spring 2025 Svitlana Pylypenko............................................................................................................. Spring 2024 Paul Gannon...................................................................................................................... Spring 2024 Stephen Maldonado........................................................................................................... Spring 2025 David Hall.......................................................................................................................... Spring 2025 Vimal Chaitanya................................................................................................................. Spring 2022 Takayuki Homma................................................................................................................ Spring 2022 Walter Van Schalkwijk........................................................................................................ Spring 2023 Tobias Glossman................................................................................................................ Spring 2023 Amin Rabiei....................................................................................................................... Spring 2023 Ramsay Blake Nuwayhid.................................................................................................... Spring 2025 Marca Doeff.......................................................................................................Secretary, Spring 2024 William Mustain...............................................Chair, Individual Membership Committee, Spring 2023

Ethical Standards Committee

Stefan De Gendt, Chair .............................................................Immediate Past President, Spring 2022 Johna Leddy.................................................................................................. Past Officer, Spring 2023 Esther Takeuchi ............................................................................................. Past Officer, Spring 2024 Marca Doeff.......................................................................................................Secretary, Spring 2024 Gessie Brisard.................................................................................................... Treasurer, Spring 2022

Finance Committee

Gessie Brisard, Chair ........................................................................................Treasurer, Spring 2022 E. Jennings Taylor.............................................................................................................. Spring 2023 Bruce Weisman.................................................................................................................. Spring 2023 Peter Foller........................................................................................................................ Spring 2022 Robert Micek...................................................................................................................... Spring 2022 Marca Doeff.......................................................................................................Secretary, Spring 2024 Tim Gamberzky............................................................................Chief Operating Officer, Term as COO

Honors and Awards Committee

Shelley Minteer, Chair ....................................................................................................... Spring 2023 Vimal Chaitanya................................................................................................................. Spring 2024 Mikhail Brik....................................................................................................................... Spring 2024 Diane Smith....................................................................................................................... Spring 2024 Alanah Fitch....................................................................................................................... Spring 2025 Shigeo Maruyama.............................................................................................................. Spring 2025 Jean St. Pierre.................................................................................................................... Spring 2025 Junichi Murota................................................................................................................... Spring 2022 Dev Chidambaram............................................................................................................. Spring 2022 Wei Tong............................................................................................................................ Spring 2022 Nianqiang Wu.................................................................................................................... Spring 2023 John Flake......................................................................................................................... Spring 2023 Fernando Garzon................................................................................................................ Spring 2023 Eric Wachsman..................................................................................................President, Spring 2022

Individual Membership Committee

Neal Golovin, Chair ........................................................................................................... Spring 2023 Alice Suroviec.................................................................................................................... Spring 2023 Uros Cvelbar...................................................................................................................... Spring 2023 John Staser........................................................................................................................ Spring 2024 Shirley Meng..................................................................................................................... Spring 2024 James Burgess................................................................................................................... Spring 2022 Luis A. Diaz Aldana............................................................................................................ Spring 2022 Mohammadreza Nazemi..................................................................................................... Spring 2022 Ashwin Ramanujam........................................................................................................... Spring 2023 Marion Jones................................................ Chair, Institutional Engagement Committee, Spring 2022 Marca Doeff.......................................................................................................Secretary, Spring 2024

Institutional Engagement Committee

Marion Jones, Chair.......................................................................................................... Spring 2022 Hemanth Jaganathan.......................................................................................................... Spring 2023 Thomas Barrera.................................................................................................................. Spring 2023 David Carey....................................................................................................................... Spring 2023 Yuyan Shao........................................................................................................................ Spring 2024 Christopher Beasley........................................................................................................... Spring 2024 Karen Poe.......................................................................................................................... Spring 2024 Alex Peroff......................................................................................................................... Spring 2022 Alok Srivastava.................................................................................................................. Spring 2022

Craig Owen........................................................................................................................ Spring 2022 Neal Golovin....................................................Chair, Individual Membership Committee, Spring 2023 Gessie Brisard....................................................................................................Treasurer, Spring 2022

Nominating Committee

Stefan De Gendt, Chair..............................................................Immediate Past President, Spring 2022 Greg Jackson..................................................................................................................... Spring 2022 Boryann Liaw..................................................................................................................... Spring 2022 William Mustain................................................................................................................. Spring 2022 Colm O’Dwyer...................................................................................Third Vice President, Spring 2022

Technical Affairs Committee

Turgut Gür, Chair.............................................................................Senior Vice President, Spring 2022 Eric Wachsman..................................................................................................President, Spring 2022 Stefan De Gendt........................................................................Immediate Past President, Spring 2022 Christina Bock.............................................................Second Immediate Past President, Spring 2022 Colm O’Dwyer.................................................................. Chair, Meetings Subcommittee, Spring 2022 Gerardine Botte........................................................... Chair, Publications Subcommittee, Spring 2022 E. Jennings Taylor................................................................... Chair, ISTS Subcommittee, Spring 2022 Christopher Jannuzzi............................................................................. Executive Director, Term as ED

Publications Subcommittee of the Technical Affairs Committee

Gerardine Botte, Chair................................................................... Second Vice President, Spring 2022 Colm O’Dwyer, Vice Chair.................................................................Third Vice President, Spring 2022 Krishnan Rajeshwar..........................................................................................JSS Editor, 12/31/2021 Robert Savinell...................................................................................................... JES Editor, 6/3/2024 Robert Kelly.................................................................................................Interface Editor, 5/31/2022 Kang Xu............................................................................................................................. Spring 2022 Cortney Kreller................................................................................................................... Spring 2022 Venkataraman Thangadurai................................................................................................ Spring 2023 Ajit Khosla......................................................................................................................... Spring 2023

Meetings Subcommittee of the Technical Affairs Committee

Colm O’Dwyer, Chair.........................................................................Third Vice President, Spring 2022 Gerardine Botte, Vice Chair........................................................... Second Vice President, Spring 2022 Jianlin Li............................................................................................................................ Spring 2023 Francis D‘Souza ................................................................................................................ Spring 2024 Paul Truelove..................................................................................................................... Spring 2022

Interdisciplinary Science and Technology Subcommittee of the Technical Affairs Committee

E. Jennings Taylor, Chair.................................................................................................... Spring 2022 Alice Suroviec ................................................................................................................... Spring 2023 Uros Cvelbar...................................................................................................................... Spring 2023 Jennifer Hite....................................................................................................................... Spring 2023 Scott Calabrese Barton....................................................................................................... Spring 2023 Alok Srivastava.................................................................................................................. Spring 2024 Diane Smith....................................................................................................................... Spring 2024 Rangachary Mukundan...................................................................................................... Spring 2024 James Fenton..................................................................................................................... Spring 2024 John Vaughey.................................................................................................................... Spring 2022 Nick Birbilis....................................................................................................................... Spring 2022 Sean Bishop....................................................................................................................... Spring 2022 Jeff L. Blackburn................................................................................................................ Spring 2022 Natasa Vasiljek................................................................................................................... Spring 2022

Symposium Planning Advisory Board of the Technical Affairs Committee

Colm O’Dwyer, Chair.........................................................................Third Vice President, Spring 2022 Shirley Meng .................................................................................... Chair, Battery Division, Fall 2022 James Noël................................................................................... Chair, Corrosion Division, Fall 2022 Jessica Koehne .................................................................................Chair, Sensor Division, Fall 2022 Jennifer Hite.................................................... Chair, Electronics and Photonics Division, Spring 2023 William Mustain..........................................................Chair, Energy Technology Division, Spring 2023 Sadagopan Krishnan ................ Chair, Organic and Biological Electrochemistry Division, Spring 2023 Andrew Hillier ..........................Chair, Physical and Analytical Electrochemistry Division, Spring 2023 Natasa Vasiljevic................................................................Chair, Electrodeposition Division, Fall 2023 Sean Bishop.......................................................Chair, High Temperature Materials Division, Fall 2023 Rong-Jun Xie...................................... Chair, Luminescence and Display Materials Division, Fall 2023 Peter Mascher.................................... Chair, Dielectric Science and Technology Division, Spring 2022 Hiroshi Imahori .................................................................. Chair, Nanocarbons Division, Spring 2022 Shrisudersan Jayaraman............................................................. Chair, Industrial Electrochemistry and Electrochemical Engineering Division, Spring 2022 E. Jennings Taylor.......... Chair, Interdisciplinary Science and Technology Subcommittee, Spring 2022

Other Representatives

Society Historian Roque Calvo.................................................................................................................. Spring 2022 American Association for the Advancement of Science Christopher Jannuzzi................................................................................. Term as Executive Director Science History Institute Katya Pomerantseva........................................................................Heritage Councilor, Spring 2022 National Inventors Hall of Fame Shelley Minteer.................................................... Chair, Honors & Awards Committee, Spring 2023

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

ECS Division Contacts High-Temperature Energy, Materials, & Processes

Battery

Y. Shirley Meng, Chair University of California San Diego Brett Lucht, Vice Chair Jie Xiao, Secretary Jagjit Nanda, Treasurer Doron Aurbach, Journals Editorial Board Representative Corrosion

James Noël, Chair Western University Dev Chidambaram, Vice Chair Eiji Tada, Secretary/Treasurer Gerald Frankel, Journals Editorial Board Representative Dielectric Science and Technology

Peter Mascher, Chair McMaster University Uroš Cvelbar, Vice Chair Sreeran Vaddiraju, Secretary Zhi David Chen, Treasurer Peter Mascher, Journals Editorial Board Representative Electrodeposition

Natasa Vasiljevic, Chair University of Bristol, UK Luca Magagnin, Vice Chair Andreas Bund, Secretary Antoine Allanore, Treasurer Takayuki Homma, Journals Editorial Board Representative Electronics and Photonics

Jennifer Hite, Chair Naval Research Laboratory Qiliang Li, Vice Chair Vidhya Chakrapani, 2nd Vice Chair Zia Karim, Secretary Erica Douglas, Treasurer Fan Ren, Journals Editorial Board Representative Jennifer Bardwell, Journals Editorial Board Representative Energy Technology

William Mustain, Chair University of South Carolina Katherine Ayers, Vice Chair Minhua Shao, Secretary Hui Xu, Treasurer Xiao-Dong Zhou, Journals Editorial Board Representative

Sean R. Bishop, Chair Sandia National Laboratories Cortney Kreller, Sr. Vice Chair Xingbo Liu, Jr. Vice Chair Teruhisa Horita, Secretary/Treasurer Xiao-Dong Zhou, Journals Editorial Board Representative

Industrial Electrochemistry and Electrochemical Engineering

Shrisudersan Jayaraman, Chair Corning Incorporated Maria Inman, Vice Chair Paul Kenis, Secretary/Treasurer John Harb, Journals Editorial Board Representative Luminescence and Display Materials

Rong-Jun Xie, Chair Xiamen University Eugeniusz Zych, Vice Chair Dirk Poelman, Secretary/Treasurer Kailash Mishra, Journals Editorial Board Representative Nanocarbons

Hiroshi Imahori, Chair Kyoto University Jeffrey Blackburn, Vice Chair Ardemis Boghossian, Secretary Slava V. Rotkin, Treasurer Francis D’Souza, Journals Editorial Board Representative Organic and Biological Electrochemistry

Sadagopan Krishnan, Chair Oklahoma State University Song Lin, Vice Chair Jeffrey Halpern, Secretary/Treasurer Janine Mauzeroll, Journals Editorial Board Representative Physical and Analytical Electrochemistry

Andrew Hillier, Chair Iowa State University Stephen Paddison, Vice Chair Anne Co, Secretary Svitlana Pylypenko, Treasurer David Cliffel, Journals Editorial Board Representative Sensor

Jessica Koehne, Chair NASA Ames Research Center Larry Nagahara, Vice Chair Praveen Kumar Sekhar, Secretary Dong-Joo Kim, Treasurer Ajit Khosla, Journals Editorial Board Representative

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

New Division Officers Electrodeposition

Chair Natasa Vasiljevic, University of Bristol Vice Chair Luca Magagnin, Politecnico di Milano Secretary Andreas Bund, Technische Universität Ilmenau Treasurer Antoine Allanore, Massachusetts Institute of Technology Division Past Chair Philippe Vereecken, IMEC Journals Editorial Board Representative Takayuki Homma, Waseda University Members-at-Large Rohan Akolkar, Case Western Reserve University Trevor Braun, NIST Amanda Clifford, University of British Columbia Massimo Innocenti, Universita degli Studi di Firenze Adriana Ispas, Technische Universität Ilmenau Toshiyuki Nohira, Kyoto University, Japan High-Temperature Energy, Materials & Processes Division

Chair Sean R. Bishop, Sandia National Laboratories Vice Chair Cortney R. Kreller, Los Alamos National Laboratory Jr. Vice Chair Xingbo Liu, West Virginia University Secretary/Treasurer Teruhisa Horita, National Institute of Advanced Industrial Science & Technology Division Past Chair Paul E. Gannon, Montana State University Bozeman Journals Editorial Board Representative Xiao-Dong Zhou, University of Louisiana at Lafayette Members-at-Large Stuart B. Adler, University of Washington Mark D. Allendorf, Sandia National Laboratories Jihwan An, Seoul National University of Science and Technology Fanglin (Frank) Chen, University of South Carolina Zhe Cheng, Florida International University Wilson Chiu, University of Connecticut Dong Ding, Idaho National Laboratory Jan Froitzheim, Chalmers University Fernando Garzon, University of New Mexico Mathias Christian Galetz, DECHEMA-Forschungsinstitut

Srikanth Gopalan, Boston University Turgut Gür, Stanford University Liangbing Hu, University of Maryland Greg S. Jackson, Colorado School of Mines Tatsuya Kawada, Tohoku University Hojong Kim, Pennsylvania State University Kang Taek Lee, KAIST Min Hwan Lee, UC Merced Wonyoung Lee, Sungkyunkwan University Olga Marina, Pacific Northwest National Laboratory Torsten Markus, Mannheim University of Applied Sciences Nguyen Minh, UC San Diego Jason Nicholas, Michigan State University Elizabeth Opila, University of Virginia Nicola Perry, University of Illinois at Urbana-Champaign Kannan Ramaiyan, University of New Mexico Sandrine Ricote, Colorado School of Mines Jennifer Rupp, Massachusetts Institute of Technology Yixiang Shi, Tsinghua University Subhash Singhal, Pacific Northwest National Laboratory Hitoshi Takamura, Tohoku University Jianhua Tong, Clemson University Enrico Traversa, University of Electronic Science and Technology of China Eric Wachsman, University of Maryland Geoffrey David Will, Queensland University of Technology Leta Woo, Cummins Bilge Yildiz, Massachusetts Institute of Technology Luminescence & Display Materials Division

Chair Rong-Jun Xie, Xiamen University Vice Chair Eugeniusz Zych, Uniwersytet Wroclawski Secretary/Treasurer Dirk Poelman, Universiteit Ghent Division Past Chair Jakoah Brgoch, University of Houston Journals Editorial Board Representative Kailash C. Misrah Members at Large Mikhail Brik, University of Tartu Marco Bettinelli, University of Verona John Collins, Wheaton College Won Bin Im, Hanyang University Tetsuhiko Isobe, Keio University Luiz Jacobsohn, Clemson University Ru-Shi Liu, National Taiwan University Kazuyoshi Ogasawara, Kwansei Gakuin University Alan Piquette, OSRAM Opto Semiconductors Alok Srivastava, Srivastava Consulting LLC

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

Division News Industrial Electrochemistry & Electrochemical Engineering Division Theodore Beck Student Travel Awards Established The IE&EE Division Theodore Beck Student Travel Award, created in memory of the 1975 ECS President and founder of The Electrochemical Technology Corp, will be awarded for the first time for travel to the 241st ECS Meeting in Vancouver, BC, Canada, from May 29 to June 2, 2022. Dr. Theodore Beck, who passed away at the age of 91 on May 28, 2017, bequeathed funds in his estate to support this award for the next five-some years. The top two award applicants at each ECS meeting will be named IE&EE Division Theodore Beck Student Travel Awardees. The enhanced travel award

carries the prestige of memorializing a major contributor to ECS and the IE&EE Division. Award recipients receive up to $2,000 each which is expected to cover most of the cost for a student to attend the meeting (i.e., registration and travel expenses). To be eligible, award recipients are required to present at a session sponsored or cosponsored by the IE&EE Division. Other traditional IE&EE Division travel awards continue to be given to fund students’ meeting registration and a portion of their travel expenses. Early Career Travel Awards are also available to subsidize travel expenses for students who received their PhDs less than five years ago.

INTERESTED IN PUBLISHING WITH ECS? Visit the ECS website to learn more about the book publishing process, information on preparing a proposal, and helpful advice on how to get your book published. QUESTIONS? If you have questions or are ready to take the next step, reach out to ECS staff at publications@electrochem.org.

www.electrochem.org/books

In Honor of John Goodenough: A CENTENARIAN MILESTONE The Editorial teams of the ECS Journal of Solid State Science and Technology and Journal of The Electrochemical Society joined to publish a focus issue comprised of select invited papers in celebration and honor of the life and contributions of Nobel Prize laureate, ECS Member, and beloved professor, Dr. John B. Goodenough. Full issue to be published in May 2022, just two months before John’s 100th birthday!

Doron Aurbach, David E. Cliffel, Francis D'Souza, Yonggang Huang, Laura H. Lewis, Arumugam Manthiram, Peter Mascher, Gerko Oskam, Laurie Peter, Fan Ren, Yang Shao Horn, Jin Suntivich, Jianshi Zhou, Xiao-Dong Zhou

Learn more at https://iopscience.iop.org/partner/ecs The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

Podcasts of Note Suggested for you by Alice Suroviec.

The Story Collider

Cinema Science

The Story Collider allows scientists and engineers to tell their own personal stories about science in their everyday lives. The stories on the podcast revolve around the human experience of scientific discovery. They also offer workshops for those who would like to develop their storytelling skills.

Scientists Heidi Febinger and Anne Gibson interview a research scientist about their favorite movie and the science behind it. This podcast is funded by the University of Utah Neuroscience Initiative.

https://www.storycollider.org

https://cinemascience.podbean.com

RadioLab

Ologies

Probably the most famous of the podcasts on this list, this podcast uses investigative journalism to answer some of the deep questions in science today. This podcast is hosted by Jad Abymrad (a MacArthur Genius Award recipient), Lulu Miller, and Latif Nasser with weekly episodes on topics that range from saving butterflies from extinction to the story behind the periodic table.

Hosted by Alie Ward, this comedic science show interviews scientists who work in different niche areas. There are interviews on “ologies” like paleontology and ecology but also more unusual ones such as spheksology (study of wasps) and medusology (study of jellyfish). https://www.alieward.com/ologies

https://www.wnycstudios.org/podcasts/radiolab/podcasts © The Electrochemical Society. 10.1149/2.F03214IF

About the Author

Alice Suroviec is Professor of Bioanalytical Chemistry and Dean of the College of Mathematical and Natural Sciences at Berry College. She earned a BS in Chemistry from Allegheny College in 2000. She received her PhD from Virginia Tech in 2005 under the direction of Dr. Mark R. Anderson. Her research focuses on enzymatically modified electrodes for use as biosensors. She is currently Associate Editor of the PAE Technical Division for the Journal of the Electrochemical Society. She is always looking for new app/website suggestions, so feel free to email her. https://orcid.org/0000-0002-9252-2468

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

SOCIETY NEWS

Graduating ECS Members This section, a new addition to the summer and winter Interface issues, celebrates the accomplishments of our community’s graduates. The inaugural list below announces ECS members who graduated from January 1 through December 31, 2021.* Join us in congratulating them on their academic success—and best wishes for their next career steps! Aysegul Abdelal Anu Adamson Takanori Akita Soroush Almassi Karrar Alofari Stefany Angarita-Gomez Mirko Ante Ryo Asakura Jaschar Atik Pedro Atz Dick Mohsen Bahrami Munir Besli Ankush Bhatia Matthew Bird Nora Buggy Kiana Cahue Utibe-Eno Charles-Granville John Corsi Michał Czachor Salik Dahal Lius Daniel Devendrasinh Darbar Andrew Dawson Tobias Deich Jay Deshmukh Manali Dhawan Wesley Dose Amina Dridi Sharmila Durairaj Hannah Dykes Rajkeerthi E Mohamed Ali Elharati Charlotte Flatebo Sankalp Koduvayur Ganeshan Steffen Garbe Sahil Garg Roby Gauthier Artem Gavrilev Panagiotis Giotakos Claudia Granja Nicholas Grundish Joseph Gurrentz Salvador Gutierrez-Portocarrero Christian Haas Karel Haesevoets Jonathan Hammond Samuel Hardisty William Hawley Cassara Higgins Qingping Hou Hung Wen Huang Matthew Hummel Nushrat Jahan Andrea Jurov

Mariko Kadowaki Hiroshi Kakinuma Sanoop Palakkathodi Kammampata Ryan Katona Nandan B. Kenchappa Alexander Klementiev Aslan Kosakian Adefunke Koyejo Robert Lavelle Alejandra Lazaro Paul Le Floch Abigail Linhart Steffen Link Aaron Liu Teng Liu Yuanchao Liu Paulette Loichet Ryan Longchamps Fazlollah Madani Sani Mudasar Mahmood Sina Matin Marvin Messing Chirag Mevada Peyman Mohtat Leo Monaco Venkata Sai Sriram Mosali Nerly Mosquera Daisaku Mukaiyama Shariful Nabil Arina Nadeina Masoumeh Naghizadeh Augustine Ndukwe Anton Neumann Ky Nguyen Robert Nissler Kaitlynn Olczak Olawale Oloye Gabriele Panzeri Mihit Parekh Benjamin Paren Caitlin Parke Eduardo Parma Jacob Pawlik Samanbar Permeh Verena Perner Gopinath Perumal Ana Flavia Petro Aswin Prathap Pitchiya David Raciti Elham Rafie Borujeny Sobana Rangarajan Jeanne-Marie Rauch Jeromy Rech Zayn Rhodes

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Mylène Robert Renato Rogosic Jimmy Rojas Holger Saare Pardis Sadeghi Shirin Saffar-Avval Ryota Saito Laura Sanford Travis Schmauss Tobias Schuler Samaneh Sharifi Golru Jana Shepa Mehrnaz Shirazi Jazlynn Sikes Mayura Silva Akhilender Singh Navid Solati Mohammad Soltani Christopher Stachurski Hellen Stephanie Michael Strebl Björn Stühmeier Akshay Subramaniam Alicja Szczepańska Kasra Taghikhani Kai-Jher Tan Delvina Tarimo Antony Raj Thiruppathi Heidi Thuv Christina Toigo Gülen Tok Bashir Usman Mariana Vasquez Jacob Wade Yudong Wang Crystal Waters Rebecca Wilhelm Kindle Williams Joseph Jo Yin Wong Htoo Wunn Melak Yosseif Chen You Shule Yu Maha Yusuf Billal Zayat Ye Zhang Yifan Zhang Tianyu Zhao Chengtian Zhou * Graduation information as of October 1, 2021. Members must list their graduation date in their ECS My Account to be included in the list.

Summer Fellowships & Colin Garfield Fink Fellowship Summary Reports Summer Fellowships Each year, ECS awards up to four summer fellowships to support graduate students continuing their research from June through August in a field of interest to the Society. The ECS Summer Fellowships program comprises four named awards: Edward G. Weston Fellowship Joseph W. Richards Fellowship F. M. Becket Fellowship H. H. Uhlig Fellowship The Society also awards the Colin Garfield Fink Summer Fellowship to one postdoctoral scientist or engineer who is a member in good standing. The Summer Fellowship and Colin Garfield Fink Fellowship recipients are each awarded US $5,000. Congratulations to the five 2021 recipients!

The Society thanks the ECS Summer Fellowship Subcommittee for reviewing the applications and selecting the outstanding recipients. Subcommittee members are: • Vimal H. Chaitanya, Subcommittee Chair, New Mexico State University • Peter Mascher, McMaster University • David S. Hall, University of Cambridge • Kalpathy B. Sundaram, University of Central Florida • Jennifer A. Bardwell, National Research Council of Canada (retired) • Yaiza Gonzalez-Garcia, Technische Universiteit Delft Interested in submitting an application for an ECS Summer Fellowship or the Colin Garfield Fink Fellowship? The 2022 award application deadline is January 15, 2022. Learn more about ECS fellowships and grants.

2021 Edward G. Weston Fellowship – Summary Report Layered Sodium Manganese Oxide as a Versatile Battery Cathode for Insertion of Monovalent Ions (Li+, Na+, and K+) in Non-aqueous Electrolytes by Krishnakanth Sada

he transition from fossil fuels to carbon-free forms of renewable energy has become a spotlight with the revolutionary emergence of efficient electrochemical energy storage systems. It enables us to realize electric mobility empowered by Li-ion battery technology.1 Nevertheless, for the past three decades, the development of battery technology has been very sluggish, and it warrants new strategies to meet the growing demand for high energy density. In this spirit, we are working to develop versatile battery cathodes, which can be used for electrochemical and electrocatalytic applications. We have synthesized layered sodium manganese oxide (Na2Mn3O7) using suites of techniques (from “dry” solid state to “wet” solution-assisted synthesis routes) to optimize the electrochemical properties. It can help to tune the morphology, particle size, and in-situ carbon coating on the particles and related properties thereof. The FESEM images (showing cubes, spheres, and inhomogeneous particles ~2 µm) were prepared using solution-combustion, emulsion, hydrothermal, and solid state routes, respectively (See Fig. 1(a).) In each synthesis, the precursor powder was calcined at 600°C for 4 h (in air) to get the desired Na2Mn3O7 target phase. Here, Na2Mn3O7 was explored as a cathode for Li-, Na- and K-ion batteries, delivering a reversible capacity of 160, 140, and 135 mA h g-1, respectively.2-5 The Mn+4 oxidation states imply initial discharge to activate Mn+4/Mn+3 active redox couple (1e- transfer per Mn). This 28

Fig 1. (a) Different synthetic procedures employed to optimize the size and shape of Na2Mn3O7 particles. (b) Comparison of galvanostatic (dis)charge profiles of Li-, Na-, and K-ion half cells. (c) Structural transformation of Na2Mn3O7 upon the insertion of Li-ions into the framework. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Fig 2. Left: Realization of double cationic redox processes upon altering the potential window. Right: Operando XRD showing triclinic (P1) to rhombohedral (R3m) phase transformation.

process is associated with ~ 1 V upshifting of operating potential for Li-ion insertion compared to Na- and K-ion insertion (See Fig. 1(b).) The topotactic insertion reaction resulted in noteworthy structural diversity. In Li-ion half cells, (de)intercalation of Li-ions triggered a triclinic (P1) to rhombohedral (R3m) phase transition in the Na2Mn3O7 structure, as shown schematically in Fig. 1(c). The initial irreversible structural modulations lead to robust cycling of LixNa2Mn3O7 with solid-solution (singlephase) reaction mechanism.3 However, it follows a reversible biphasic reaction mechanism in the case of Na-ion and K-ion (de)interaction in Na2Mn3O7.2,3 A detailed investigation was carried out to understand the Li-ion (de) intercalation properties in the Na2Mn3O7 host. By tuning the potential window (1.0 to 4.8 V), we have shown the activation of two-step (de)lithiation in Na2Mn3O7 involving Mn4+/Mn3+ followed by Mn+3/ Mn+2 redox processes forming LixNa2yMn3O7 phases (Fig. 2, left). Each of the three Mn units can exhibit double cationic redox (Mn+4/Mn+3 and Mn+3/Mn+2) activity, thus allowing more than 3e- insertion into the structure. Operando x-ray diffraction studies verified a phase transformation during the first discharge (Fig. 2, right). Further, we noticed a thin volume expansion during the (de)intercalation process. It reinforces the “pillaring effect” of residual Na-ions present and stabilizes the structure from Mn-dissolution and structural collapse after multiple cycles. This double cationic redox can enable multiple electron insertion, leading to doubling of capacity (from 160 to 300 mA h g-1).5

To summarize, the concept of versatile cathode materials can add new dimensions in the field of next-generation batteries. We have successfully synthesized Na-Mn-O ternary mixture using different synthetic techniques and have demonstrated the intercalation properties of Li-, Na-, and K-ions. Further, optimization of the potential window leads to activation of double cationic redox activity. It benchmarks the first demonstration of double cationic redox in Na2Mn3O7, delivering over 280 mA h g-1 capacity. Indeed, Na-Mn-O forms a rich playground for secondary battery materials. © The Electrochemical Society. DOI: 10.1149/2.F04214IF

at Kakatiya University, India. He was an INSPIRE Scholar from 2009 to 2014 and an INSPIRE Fellow from 2016 to 2021. With support from the Newton-Bhabha Fund PhD Placement Program, he visited the University of Cambridge from November 2020 to March 2021. In 2019, as Japan Society for the Promotion of Science HOPE Fellow, he attended the 11th HOPE Meeting with Nobel Laureates in Okinawa, Japan. Combining experimental and theoretical tools, he has explored the synthesis-structure-electrochemistry of economic battery cathodes, this work to the development of suites of novel cathode materials based on AxM3O7 (A= Li/ Na/K/Zn/Mg/Ca/Al; M= Mn/V) chemistry. https://orcid.org/0000-0001-6119-6164

Acknowledgments

References

The author thanks The Electrochemical Society (ECS) for the E. G. Weston Summer Research Fellowship and Prof. Prabeer Barpanda for his thesis supervision. The author also thanks Prof. Valérie Pralong (CRISMAT, France) for hosting him as a visiting student under the LAFICS program for two months.

1. K. Mizushima, P. C. Jones, P. J. Wiseman, and J. B. Goodenough, Mater. Res. Bull., 15, 783 (1980). 2. E. Adamczyk and V. Pralong, Chem. Mater., 29, 4645 (2017). 3. K. Sada, B. Senthilkumar and P. Barpanda, ACS Appl. Energy Mater., 1, 5410 (2018). 4. K. Sada, B. Senthilkumar and P. Barpanda, ACS Appl. Energy Mater., 1, 6719 (2018). 5. K. Sada, B. Senthilkumar and P. Barpanda, Indian Provisional Patent, 202141038342 (2021).

About the Author

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Krishnakanth Sada is in the final year of his PhD at the Indian Institute of Science, Bengaluru, with Prof. Prabeer Barpanda as PhD advisor. Sada completed his BS and MS (2014) in Chemistry

2021 Joseph W. Richards Fellowship – Summary Report Toward On-Chip Electronic Monitoring of Bacterial Conjugation by Derrick Butler

ntercellular conjugation is a primary communication method by which bacteria transfer genetic material from one cell to another.1,2 Because conjugation mediates the transfer of genetic material, it enables the spread of antibiotic resistance and other virulence factors within a population. Oftentimes, conjugative pili, which are thin, flexible filaments of approximately 5 micrometers in length that extend from a donor cell to a recipient,2 serve as a bridge for the transfer of the genetic material. Upon successful conjugation, the pilus retracts, and cells are pulled toward one another. Fluorescence imaging2 and atomic force microscopy (AFM)3,4 are demonstrated methods for studying these mechanical interactions. Although effective, these techniques have low throughput and require extensive sample preparation (e.g., flourescent labeling), making realtime monitoring of conjugation dynamics challenging. To address these shortcomings, we are exploring two-dimensional (2D) materials as a strain-sensitive platform for on-chip, electronic monitoring of conjugation events (See Fig. 1(a).) Graphene is first used as

a proof-of-concept 2D material. Sensor fabrication begins with the selective etching of graphene to remove superfluous material outside the active device region, followed by the deposition of an array of interdigitated Ti/Au contacts. Lastly, the sensor is encapsulated with an insulating SiO2 layer, leaving individual graphene channels exposed for further functionalization. The functionalization process begins by incubating the graphene in a solution of 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE), which non-covalently attaches to graphene and preserves its excellent electrical properties.5 Next, the sensors are incubated with the target antibody (Ab), Escherichia coli (E. coli) in this case. Lastly, incubation with a bovine serum albumin (BSA) protein blocking layer prevents non-specific binding of bacteria. Raman spectra are recorded throughout the functionalization process, Fig.1(b), and show a blue-shift of the characteristic G and 2D Raman peaks, indicative of p-doping.6 Additionally, a small shoulder is seen around 1620 cm-1 corresponding to the resonance of the pyrene group in PBASE.7 We use AFM to map the graphene surface after

Ab functionalization, which shows welldispersed Abs on the graphene. Moreover, scanning electron microscopy (SEM) is used to confirm the selective attachment of E. coli to the functionalized graphene channel. Here, the bacteria are found to be immobilized on the exposed (nonpassivated) graphene channel, while the passivated regions covering the electrodes are essentially cell-free, thus indicating a successful functionalization process. We now shift focus to the electronic properties of the graphene sensor. Figure 1(c) shows I-V curves taken at each step of the functionalization process. The lowest resistance is seen for pristine graphene, which gradually trends upward over the course of functionalization as graphene is exposed to various chemicals that may introduce defects or dopants into the sample. In Fig. 1(d), an electrolytic gating scheme with an Ag/AgCl gate electrode is introduced to modulate the carrier density in the graphene film. From the figure, a minimum in IDS is seen around -0.45 V, indicating n-type graphene. Further investigation is needed to understand how the carrier density can be

Fig. 1. (a) A schematic of the envisioned platform, whereby antibody functionalized graphene is used to immobilize bacteria. Neighboring bacteria then conjugate and pull toward one another, causing a measurable shift in the electrical properties of graphene resulting from the induced strain. (b) The Raman spectra of graphene throughout the functionalization process. (c) The DC current-voltage response of graphene over the course of the functionalization process. Inset: The extracted resistance values (n = 3). (d) The transfer curve of graphene measured with an Ag/AgCl gate electrode in 100 mM KCl electrolyte. 30

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

tuned such that the 2D material is most sensitive to conjugation-induced strain. These include studying the effect of nanoengineering, layer number, modulation of surface chemistry, and the substrate. If successful, the proposed sensor could enable real-time, label-free mapping of conjugation dynamics under a range of environmental stressors, thus improving our understanding of the biophysical conjugation mechanism and eventually improving clinical outcomes.

Acknowledgments The author would like to thank The Electrochemical Society for their support through the Joseph W. Richards Summer Fellowship. The author would also like to thank his thesis advisor, Prof. Aida Ebrahimi, for providing invaluable guidance and unwavering support throughout the past four years. The author is also grateful for insightful discussions with Prof. Jasna Kovac and Taejung Chung throughout this project. This research was made possible through support from the United States National Institutes of Health (NIH). However, the content of this report does not necessarily represent the official views of NIH. © The Electrochemical Society. DOI: 10.1149/2.F05214IF

About the Author

References

Derrick Butler is currently a fourth-year PhD candidate in the lab of Prof. Aida Ebrahimi in the Department of Electrical Engineering at Pennsylvania State University. His focus is on the development of electrochemical and electronic analytical platforms for biomedical and environmental applications, ranging from drug screening to medical diagnostics. His h-index is 5; he has published seven research articles (three as first or co-first author); is co-first author of one review paper; and authored a chapter on impedimetric detection of bacterial viability for a book that is in press. At Pennsylvania State University, Butler received the Harry G. Miller Fellowship in Engineering Award (2020) and University Graduate Fellowship (2018– 2019). Butler was a member of the Sigma Pi Sigma Physics Honor Society at the University of Vermont, where he completed his BS in Physics (2015). He received an MSE in Materials Science and Engineering from the University of Pennsylvania (2017). Butler serves as President of the ECS Pennsylvania State University Student Chapter. https://orcid.org/0000-0003-3514-9326

1. E. Cabezón, J. Ripoll-Rozada, A. Peña, F. de la Cruz, and I. Arechaga, FEMS Microbiol. Rev., 39, 81 (2015). 2. M. Clarke, L. Maddera, R. L. Harris, and P. M. Silverman, Proc. Natl. Acad. Sci. U.S.A. 105, 17978 (2008). 3. A. Touhami, M. H. Jericho, J. M. Boyd, and T. J. Beveridge, J. Bacteriol., 188, 370 (2006). 4. A. Beaussart, A. E. Baker, S. L. Kuchma, S. El-Kirat-Chatel, G. A. O’Toole, and Y. F. Dufrêne, ACS Nano, 8, 10723 (2014). 5. N. I. Khan, M. Mousazadehkasin, S. Ghosh, J. G. Tsavalas, and E. Song, Analyst, 145, 4494 (2020). 6. R. Beams, L. G. Cançado, and L. Novotny, J. Phys. Condens. Matter, 27, 083002 (2015). 7. Y. Liu, L. Yuan, M. Yang, Y. Zheng, L. Li, L. Gao, N. Nerngchamnong, C. T. Nai, C. S. S. Sangeeth, Y. P. Feng, C. A. Nijhuis, and K. P. Loh, Nat. Commun., 51, 5461 (2014).

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2021 F. M. Becket Fellowship – Summary Report Measuring Transient Electrochemistry of Lithium Metal Anodes under Varying External Stack Pressures by Wesley Chang

ithium metal anodes are challenged by the inherent chemical and electrochemical reactivity of lithium metal, which is further exacerbated by non-uniform high surface area deposition. Recently, lithium difluoro(oxalato)borate (LiDFOB) salt coupled with a fluorinated solvent (DEC:FEC, 1:1 v/v%) has been demonstrated to result in densely deposited lithium morphology along with high Coulombic efficiencies due to a stable solidelectrolyte-interphase.1,2 Along with other newly discovered electrolyte compositions for stable lithium deposition, these studies typically utilize high stack pressures, >1 MPa, and sometimes elevated temperatures. These developments are promising, and would further benefit from a study that maps out the effects of varying stack pressure and temperature on lithium anode mechanics, chemistry, and electrochemistry. Increased stack pressure leads to mechanical compression, leading to densely deposited lithium metal. Elevated temperatures lead to faster reaction rates and improved transport. While conventional tungsten wire microelectrodes are useful for careful electrochemical measurements with minimal ohmic overpotentials, such microelectrode configurations are not

able to control for uniaxial stack pressure, an important variable in commercial lithium metal cells. To enable careful electrochemical measurements corrected for large ohmic drops as a function of stack pressure, we construct microelectrodes in a pouch cell format, using a mask to minimize the total electrochemical surface area (See Fig. 1(a).) We incorporate a reference electrode in a geometrically uniform ring around the active area, to further minimize electrochemical noise from an unstable lithium metal counter electrode. (Fig. 1(a) shows the cell schematic, Fig. 2(a) shows a photo of a sample cell.) Constant stack pressure is applied with a pneumatic cylinder that compresses a pouch cell between the cylinder rod and a plate. We demonstrate the reliability and reproducibility of this cell configuration for measuring peak stripping currents and other voltammetric behavior as a function of stack pressure. (See Fig. 1(b).) We find, for the case study of LiDFOB in DEC:FEC, an expected relationship with temperature similar to microelectrode studies by Verbrugge and Koch3 but no correlation with stack pressure. The peak stripping current increases with temperature, but does not change with stack pressures ranging

between 0.4 MPa and 1.4 MPa. (See Fig. 1(b).) Elevated temperatures improve transport which manifests as a higher peak stripping current. On the other hand, higher stack pressures produce compact and lower surface area deposits, which do not appear to affect the transient current response to applied voltage. The results are reproducible as shown by the duplicate test in Fig. 2(b), and the cyclic voltammetry peaks are more ohmically dominated with larger electrodes. (See Fig. 2(c).) Therefore, the small active area pouch cell provides a reliable format for reducing overpotentials while enabling both temperature and stack pressure-controlled studies of transient electrochemistry. The results also complement our existing analysis of the mechanical and chemical changes in LiDFOB DEC:FEC, where elevated stack pressures enable improved performance by acting as a mechanical constraint, and elevated temperatures improve performance by forming a lower impedance solid-electrolyte-interphase with a different chemical composition. © The Electrochemical Society. DOI: 10.1149/2.F06214IF

Fig. 1. (a) Schematic of three-electrode masked pouch cell design. (b) Cyclic voltammetry at varying stack pressures and temperatures. 32

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Fig. 2. (a) Image of a sample pouch cell showing the lithium foil reference and the mask. (b) Duplicate test cell with masked electrode, indicating reproducible data. (c) Cyclic voltammetry of a large pouch cell without mask.

Acknowledgments The author would like to express his gratitude to The Electrochemical Society for granting him the F. M. Becket Summer Research Fellowship. The author would like to express his appreciation to his thesis advisor, Dr. Daniel Steingart, for his mentorship and continued support.

About the Author Wesley Chang is a final year PhD candidate in Dr. Daniel Steingart’s group at Columbia University. His research focuses on understanding the complex chemo-mechanical dynamics of various lithium metal batteries. https://orcid.org/0000-0002-9389-1265

References 1. R. Weber, M. Genovese, A. J. Louli, S. Hames, C. Martin, I. G. Hill, and J. R. Dahn, Nature Energy, 4, 683 (2019). 2. A. J. Louli, A. Eldesoky, R. Weber, M. Genovese, M. Coon, J. deGooyer, Z. Deng, R. T. White, J. Lee, T. Rodgers, R. Petibon, S. Hy, S. J. H. Cheng, and J. R. Dahn, Nature Energy, 5, 693 (2020). 3. M. W. Verbrugge and B. J. Koch, J. Electrochem. Soc., 141, 3053 (1994).

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2021 H. H. Uhlig Fellowship – Summary Report Mechanistic Understanding of Lithium Dendrite Formation in All-Solid-State Batteries by Sathish Rajendran

igh demand for lithium-ion batteries in portable electronics, electric vehicles, and grid energy storage has spurred research on the next generation of batteries with very high energy densities.1 All-solid-state battery (ASSB) technology with lithium metal anode holds great promise in energy storage devices as it can provide higher energy density and better safety compared to conventional batteries.2 Among the several types of solidstate electrolytes, the garnet-type cubic Li7La3Zr2O12 (LLZO) solid-state electrolyte (SSE) has generated special attention because of its stability toward lithium-metal anodes, relatively high ionic conductivity, and wide electrochemical stability window.3 However, achieving target level performance using garnet-type SSE will be nearly impossible without addressing key issues related to (1) propagation of lithium dendrites that leads to the internal short

circuit of the battery, (2) its high interfacial impedance with metallic lithium due to its poor wetting nature, and (3) poor mechanical stability at cathode interface due to volume changes within the cathode.4 Among the above-mentioned issues, the propagation of lithium dendrites across the SSEs at lower current densities than in liquid electrolytes remains unclear. Further, lithium dendrites were found to propagate specifically through the grain boundaries of the SSE.5 Among multiple theories like stress induced cracking, increase in specific current due to the contact loss with the electrode, and porosity of the SSE, the higher electronic conductivity of the garnet-type SSEs is widely accepted to be the main reason for the propagation of lithium dendrites.6 However, this theory cannot explain why the tendency for dendrite propagation decreases with increasing temperature, which is proven to increase the electronic conductivity of the

electrolyte.4 This leads to the assumption that there is more than one critical factor that determines the propagation of lithium dendrites. Understanding lithium dendrite propagation in SSEs requires highly advanced techniques due to the challenges arising from the lack of characterization techniques to visualize the interior of a solid. In this work, a high-pressure in-situ cell was made to monitor the dynamic changes occurring within the ASSB under cycling using multiple characterization techniques. It involved a custom design using 3D printing of a cell as shown in Fig. 1. A symmetrical cell with SSE sandwiched between two Li foils was cut in half using milling techniques. The resulting crosssection was initially analyzed though optical microscopy under argon atmosphere during a Li plating/stripping process, as shown in Fig. 2. Different types of lithium metal deposits were observed inside the SSE at a current density of 0.1 mA cm-2, some of which are (1) propagation of Li metal from the Li electrodes in needle-like protrusions, Fig. 2(a); (2) formation of isolated deposits of Li inside the SSE, Fig. 2(b); and (3) deposition of Li metal inside of the voids of the SSE, Fig. 2(c). Although multiple morphologies formed, most of them were reversible when the current applied to the cell was reversed. Formation of metallic Li inside the SSE confirms the availability of electrons that aids electrochemical reduction of Li. Similar experiments with LiFePO4 cathode and Li4Ti5O12 anode at very high current (2 mA cm-2) did not show such reduction of Li ions to Li metal inside the SSE due to the absence of Li plating potential, which is essential for the lithium reduction process. To find the reason behind the decrease in Li dendrite formation with the increase in temperature, further experiments focused on studying the variation of these dendritic structures with multiple modifications by (1) introducing interlayers that are electron blocking (h-BN, polymers) and conducting (Au) and other materials like Al2O3, and Si3N4; (2) varying the relative density of the electrolyte; and (3) varying the electronic conductivity of the SSE by altering the dopants. The introduction of an electron

Fig. 1. Schematic representation of the custom designed in-situ cell setup.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

About the Author Sathish Rajendran is currently a fourth-year graduate student at Wayne State University, with Prof. Leela Arava as his advisor. Prior to joining Wayne State University, he completed his BTech in Chemical and Electrochemical Engineering at the CSIR-Central Electrochemical Research Institute, India. His research interests include understanding and designing interfaces for all-solid-state electrochemical cells. https://orcid.org/0000-0003-4605-3784

References

Fig. 2. Optical microscopy images of the LLZO|Li interface during Li plating process at (i) initial, (ii) 10 min, (iii) 20 min, and (iv) 30 min at a current density of 0.1 mA cm-2.

blocking interlayer inhibited the Li plating ability inside the SSE to a certain extent, and the opposite was achieved with an electronically conducting interlayer like Au. Variation of dopants in LLZO influenced the ionic conductivity to a greater extent than the electronic conductivity, and a trend of increasing dendrite formation ability with the decrease in ionic conductivity was observed. However, the effect of ionic conductivity on lithium dendrite formation in SSEs requires additional evidence. Subsequent studies are to be performed with neutron tomography techniques using the same in-situ cell setup, which can potentially give some deep insights into the mechanistic understanding behind dendrite propagation in SSEs. Although x-ray tomography studies have been carried out previously to understand lithium dendrite propagation, they cannot detect lithium directly and often confuse dendrite

propagation with other defect sites present in the SSE.7 Experiments using neutron tomography can give detailed information, as the neutrons can detect lithium metal directly. © The Electrochemical Society. DOI: 10.1149/2.F07214F

Acknowledgments The author thanks The Electrochemical Society for its support through the H. H. Uhlig Summer Research Fellowship and his PhD advisor, Prof. Leela Arava, for the continuous support and valuable thoughts throughout the project. The author would also like to thank Kiran Mahankali, graduate student, who helped with some of the instrumental studies for this work.

a free preprint service for electrochemistry and solid state science and technology

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

1. S. Rajendran, Z. Tang, A. George, A. Cannon, C. Neumann, A. Sawas, E. Ryan, A. Turchanin, and L. M. R. Arava, Adv. Energy Mater., 2100666 (2021). 2. S. Rajendran, A. Pilli, O. Omolere, J. Kelber, and L. M. R. Arava, Chem. Mater., 33, 3401 (2021). 3. J. C. Jones, S. Rajendran, A. Pilli, V. Lee, N. Chugh, L. M. R. Arava, and J. A. Kelber, J. Vac. Sci. Technol. A, 38, 023201 (2020). 4. S. Rajendran, N. K. Thangavel, K. Mahankali, and L. M. R. Arava, ACS Appl. Energy Mater., 3, 6775 (2020). 5. E. J. Cheng, A. Sharafi, and J. Sakamoto, Electrochim. Acta, 223, 85 (2017). 6. F. Han, A. S. Westover, J. Yue, X. Fan, F. Wang, M. Chi, D. N. Leonard, N. J. Dudney, H. Wang, and C. Wang, Nat. Energy, 4, 187 (2019). 7. J. A. Lewis, F. J. Q. Cortes, Y. Liu, J. C. Miers, A. Verma, B. S. Vishnugopi, J. Tippens, D. Prakash, T. S. Marchese, S. Y. Han, C. Lee, P. P. Shetty, H.-W. Lee, P. Shevchenko, F. De Carlo, C. Saldana, P. P. Mukherjee, and M. T. McDowell Nat. Mater., 20, 503 (2021).

www.electrochem.org/ecsarxiv 35

2021 Colin Garfield Fink Postdoctoral Summer Fellowship – Summary Report Luciferase – Functionalized 3D Highly Porous Gold-based Electrochemical Biosensors by Ali Othman relatively low cost.5,6 Recent advances in electrochemical biosensorics have focused on new materials and strategies to improve specificity, sensitivity, stability, and response time.7 Herein, we aim to develop an electrochemical biosensor device by modification of a screen-printed electrode (SPE) with highly porous Au nanostructures and a bioluminescence (BL)-producing enzyme (luciferase). This approach leverages the enhanced electrochemically active surface area and the mass transport effect as well as offers an alternative configuration for optical output from the enzyme. The BL presents an instantaneous measurement of enzyme activity and can be exploited to show that the enzyme is being electrochemically controlled (an ON-OFF switchable sensor). The electrochemical biosensor was prepared by growing highly porous Au nanostructures on Au-SPE using a novel

and simple electrodeposition process (Fig. 1). The solid Au electrodes were first cleaned by cyclic voltammetry (CV) with a solution of 0.5 M H2SO4 in the range of 0.0 to 1.6 V for 30 cycles. Thereafter, Au nanostructures were electrodeposited and gas bubbling was used as a self-template.8,9 The former porous Au modified SPE was then used to develop an enzymatic luc-based biosensor. The SEM image of the SPE after modification reveals a highly porous 3D structure surface. Furthermore, the modified electrode exhibited a significant increase of the real surface area with 4x104 µC/cm2—

A) 15 10 5 I/ mA

lectrochemical biosensors are continually developing given new insights into a variety of fields thanks to features such as high sensitivity, miniaturization, fast response, portability, ease of use, and low cost.1,2 Sensors based on chemoelectrocatalysis often suffer from drawbacks such as low sensitivity and interference by electroactive substances present in real matrices, which makes it very challenging to find suitable materials for various potential applications. There is significant literature concerning the development of functional electrodes based (bio)sensors aiming to enhance communication between biological molecules and electronic materials.3,4 The use of biorecognition elements, such as enzymes, antibodies, and proteins, provides highly specific recognition events, which increases the specificity of these sensors and confers fast analysis with

Bare Au-SPE Modiﬁed Au-SPE (porous)

0 -5 -10 -15 -20 -25

D-Luciferin +ATP + Mg2+ + O2

OxyLuciferin + Light

Luciferase

I/ µA HAuCl4

Potential sweeping

Fixed potential

1.2 1.0 0.8

Modified Au-porous O O

O NH2

Cysteamine

S S

O H

Glutaraldehyde

N S

1.0

Luciferase (Luc) Modified Au-porous/ Luc-based sensor

Fig. 1. (a) The bioluminescent enzymatic reaction. (b) A schematic representation of the modification of the electrochemical biosensor with the corresponding SEM images and the surface map of the 3D structure. 36

150

y = -0.017x + 1.59 R2 = 0.9888

I / µA

90 120 Time, (min)

Linear range: 10 - 40 µM

1.4 1.2

NH2 NH2 NH2 NH2

1.6

1.4

10 µm HAuCl4

0.4 0.8 1.2 E / V (vs. Ag/AgCl)

B) 1.6

10 µm

0.0

0.8

30 40 50 [D-Luc.], µM

Fig. 2. (a) CV of the bare and modified Au-SPE. (b) Chronoamperometry curve upon successive additions of D-luc. (c) The corresponding calibration curve with Eapp = – 0.60 V vs Ag|AgCl. 1

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

1000 times-higher compared to the bare one. (See Fig. 2(a).) Figure 2 (b–c) shows the electrochemical performance toward the Luciferin addition, which exhibited a concentration-dependent behavior with a low concentration of 10 µM. The solution tested includes ATP and D-Luc in Tris-HCl buffer (pH 7.8) under dark conditions. This result could be due to the reduction of the O2 amount due to its being consumed within the luciferase reaction. Future and ongoing directions are to further investigate the biosensor for ATP detection, and to monitor both the bioluminescence and the current simultaneously using the confocal microscope to understand the nature of the bioluminescent response in relation to the electrochemical reactions. © The Electrochemical Society. DOI: 10.1149/2.F08214IF

Acknowledgments

References

The author is grateful for the funding support received from the ECS Colin Garfield Fink Summer Fellowship and would like to express his gratitude to Prof. Evgeny Katz for his guidance and encouragement.

1. J. S. del Río, O. Y. F. Henry, P. Jolly, and D. E. Ingber, Nat. Nanotechnol., 14, 1143 (2019). 2. D. W. Kimmel, G. LeBlanc, M. E. Meschievitz, and D. E. Cliffel, Anal. Chem., 84, 685 (2012). 3. S. Pedireddy, H. Lee, W. Tjiu, I. Y. Phang, H. R. Tan, S. Q. Chua, C. Troadec, and X. Y. Ling, Nat. Commun., 5, 4947 (2014). 4. S. Vigneshvar, C. C. Sudhakumari, B. Senthilkumaran, and H. Prakash, Front. Bioeng. Biotechnol., 4, 11, (2016). 5. P. Arora, A. Sindhu, N. Dilbaghi, and A. Chaudhury, Biosens. Bioelectron., 28, 1 (2011). 6. E. Katz, J. Wang, M. Privman, and J. Halámek, Anal. Chem., 84, 5463 (2012). 7. I. H. Cho, D. H. Kim, and S. Park, Biomater. Res., 24, 6 (2020). 8. P. Bollella, Y. Hibino, K. Kano, L. Gorton, and R. Antiochia, Anal. Chem., 90, 12131 (2018). 9. P. Bollella, Nanomaterials, 10, 722 (2020).

About the Author Ali Othman is a postdoctoral researcher in Prof. Evgeny Katz’s group at Clarkson University. His current research interests focus on the development of novel and functional nanomaterials for (bio) sensing and wearable devices applications. http://orcid.org/0000-0002-7960-4995.

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SOCIETY PEOPLE NEWS

In Memoriam ... Wolf Vielstich 1923–2021

It is with great sadness that we inform you that Prof. Dr. Wolf Vielstich, our valued colleague and long-term ECS member, passed away on August 27, 2021. His work and passion shaped electrochemistry in Germany and around the world in a unique way. He was a brilliant researcher and his contributions in the field of fuel cells and electrochemical spectroscopy were profound and enduring. Besides research, teaching and training his students and doctoral candidates was very dear to him.

Over the years, he and his wife, Dr. Teresa Iwasita-Vielstich, worked with many young and established researchers in electrochemistry who were motivated and inspired by Prof. Vielstich’s enthusiasm for science. During breaks, he often invited his discussion partners for a table tennis match, where he was rarely defeated, even at the age of 80. Electrochemistry, his textbook written with Prof. Dr. Carl H. Hamann and Prof. Andrew Hamnett, was certainly the first reference for many of us. This textbook, as well as the Handbook of Fuel Cells which he coedited, will always be with us. Wolf, we thank you for the many things that you taught us and the many wonderful days that we experienced with you! This notice was contributed by Prof. Gessie Brissard, Université de Sherbrooke, ECS Treasurer.

SEARCHING FOR PEOPLE NEWS Interface is searching for People News for upcoming issues. If you have news you would like to share with the Society about a promotion, award, retirement, or other milestone event, please email the content to:

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Guest Editor: Alice Suroviec Special Issue on Diversity, Equity, and Inclusion in Electrochemistry Plus • A sneak peak of the 241st ECS Meeting in Vancouver May 29–June 2, 2022 • The 2021 Year in Review • The 2021 Class of Highly Cited Researchers • Editorial Board Appointments • Pennington Corner from ECS Executive Director/CEO Christopher J. Jannuzzi

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

TECH HIGHLIGHTS Li2NiO2F a New Oxyfluoride Disordered Rocksalt Cathode Material This article is part of the Focus Issue on Future of Intercalation Chemistry for Energy Storage and Conversion in Honor of M. Stanley Whittingham. The development of cobalt-free cathode materials is a significant challenge for future generations of lithiumion batteries. In recent years, mixed anion oxyfluorides have been attracting attention, as an alternative to conventional layered oxide cathodes. Researchers from University of Oxford and the Faraday Institution have reported on the synthesis of a new oxyfluoride disordered rocksalt cathode material in the form of Li2NiO2F. The initial specific capacity after the first charge to 4.8 V was 300 mAh g−1, of which 200 mAh g−1 was recovered during the subsequent discharge to 2.0 V. Operando electrochemical mass spectrometry (OEMS) revealed that there is a significant oxygen loss during the first charge which may be the cause of the irreversible capacity fading observed for subsequent cycles. This report highlights the need to investigate alternative cathode materials and Li2NiO2F has potential to become a promising Cofree cathode if further research leads to the suppression of O loss and increased capacity retention. From: X. Xu, L. Pi, J.J. Marie, et al., J. Electrochem. Soc., 168, 080521 (2021).

TiO2 Nanotube Heterostructure Modified with a Metal-Organic Framework Showing Robust Stability for Photocathodic Protection The concept of photocathodic protection of metals has been around for >25 years. However, application of this particular corrosion protection strategy has been hindered by the intrinsic properties (e.g., wide band gap) of the commonly selected photoanode material, TiO2. Recent research, therefore, has focused on modification of TiO2 photoanodes with various cocatalysts. In a new study, researchers have investigated the modification of TiO2 with zeolitic imidazolate framework-67 (ZIF67), a metal-organic framework (MOF). MOFs are attractive for this application for several reasons, including their high surface area, thermal chemical stability, low cost, and well-studied preparation methods. The ZIF-67-modified TiO2 material was prepared via a solution self-assembly method and characterized afterward using a variety of materials characterization and electrochemical techniques. Through these experiments, stability in 3.5% sodium chloride (a simulated marine environment) was demonstrated, along with enhanced photoelectrochemical and photocathodic performance. Morphology (e.g., MOF size) was shown to affect this performance, and a proposed mechanism for photocathodic

protection of 304SS by the ZIF-67modified TiO2 material was outlined. This research is a promising next step in making photocathodic protection a viable corrosion protection strategy. From: X. Lu, L. Liu, et al., J. Electrochem. Soc., 168 071513 (2021).

Operando Laser Scattering: Probing the Evolution of Local pH Changes on Complex Electrode Architectures Electrodeposition is used in the semiconductor industry to metallize patterned wafers with nm-scale features. Plating additives achieve bottom-up or superconformal electrodeposition by suppressing reactivity of the flat wafer surface, leaving most reaction to occur in the features. This leads to locally high current densities in the features. With some metals, namely cobalt, electrodeposition is unavoidably tied to the hydrogen evolution reaction. This results in localized pH gradients, due to consumption of H+. A team of researchers from the University of Bern led a project to measure pH gradients using a non-invasive operando setup based on the Tyndall effect—a type of light scattering occurring in colloidal solutions. A pH probe that precipitates at pH 4.5 was used to observe local precipitation with laser light passing over the wafer surface. Rate of pH change was found to be a function of feature pitch, and after only 7 s of plating, precipitation was observed over the features with the smallest pitch (40–50 nm), with larger features following. A noninvasive probe such as this can shed light on high-value systems important in the semiconductor industry. From: V. Grozovski, P. Moreno-García, E. Karst, et al., J. Electrochem. Soc., 168, 072504 (2021).

Functionalized Embedded Monometallic Nickel Catalysts for Enhanced Hydrogen Evolution: Performance and Stability Hydrogen production from an AEM electrolyzer needs highly active HER catalysts. Bifunctional metal-metal oxide catalyst is one promising non-Pt catalyst to significantly boost HER activity, but it can easily passivate or form metal hydrides when anodically or cathodically polarized. Doan et al. developed a functionalized monometallic Ni catalyst embedded in carbon matrix: Ni2+ was chelated with cupferron, then thermally decomposed to form Ni/Ni oxide particles which dispersed with carbon. The stability of this functionalized catalyst (Ni functionalized Ketjen Black, NFK) was compared with non-functionalized Ni catalyst (Ni/C) and bifunctional mixed metal oxide catalyst (Ni-Cr/C) in both RDE and hydrogen-pumped AEM full cell configuration. Ascertained from XANES and FT-EXAFS spectra, NFK demonstrated less metal oxide formation than the other

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

two after electrochemical tests. In this paper, part of the Focus Issue on PEM Fuel Cell & PEM Water Electrolyzer Durability, NFK showed faster Heyrovský mechanism, higher hydride oxidation speed, and slower hydride formation. Lastly, NFK showed a much slower voltage loss compared to the other two catalysts when maintaining the same current density equal to 500 mA/cm2 during HER in full cell configuration, which further validates its superior performance. From: H. Doan, I. Kendrick, R. Blanchard, et al., J. Electrochem. Soc., 168, 084501 (2021).

Capacitance Properties of Chemically Prepared Carbon Nanostructure/ Polyazulene Composites Study of new materials for efficient energy storage has been gaining momentum to enable climate-friendly energy technologies. One such class of materials is conducting polymers. Stability of these polymers are impacted by the switching from p-type to n-type. A team at Universities of Bialystok, Poland, and of Padova, Italy, and the Polish Academy of Sciences has come up with composite structures to improve stability. Electrochemical polymerization of azulene was carried out on carbon micro-structures such as single-walled carbon nanotubes, multi-walled carbon nanotubes, and singlelayer graphene oxide. The researchers found that the resulting morphology of polyazulene and thermal stability depended on the type of carbon micro-structure. The group also showed the impact of heat treatment of the composites on the effective area and electrochemical performance. The study showed a correlation between the conductivity of composites and the resulting capacitance; a 5x improvement in capacitance was obtained when compared with polyazulene alone. Mechanistic understanding was studied by the group using XPS C1s spectra, thus aiding in future study and optimization of structures like these for energy storage applications. From: E. Gradzka, G.A. Rizzi, et al., J. Solid State Science and Technology, 10, 091017 (2021).

Tech Highlights was prepared by Joshua Gallaway of Northeastern University, Mara Schindelholz of Sandia National Laboratories, David McNulty of University of Limerick, Chao (Gilbert) Liu of Shell, Chock Karuppaiah of Vetri Labs, and Donald Pile of EnPower, Inc. Each article highlighted here is available free online. Go to the online version of Tech Highlights in each issue of Interface, and click on the article summary to take you to the full-text version of the article.

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Hydrogen's Big Shot by Nemanja Danilovic and Iryna Zenyuk

e are at the confluence of two significant worldwide events. First, the incredible decrease in the cost of renewable electricity (generated by solar and wind) and its accelerating deployment which is generating a demand for energy conversion and storage devices. Secondly, we are seeing a need to decrease our carbon emissions from vast sectors of our economies in order to combat, decelerate, and reverse climate change. The United States and many European countries have set a goal to reach net-zero carbon emissions by 2050. To that end, several energy conversion technologies are enabling hydrogen’s time to help achieve these goals set at the state and country level throughout the world to help decarbonize beyond the transportation sector into heating, food production, metallurgy, and refining. In this spirit, this issue brings to light various aspects of why now is the right time for hydrogen deployment at scale, and how the Electrochemical Society can help contribute to achieving a cleaner, brighter future. Alongside copious worldwide hydrogen technology research, development, and deployment funding announced in the last year, the US Department of Energy has issued its first EarthShot Challenge, the Hydrogen Shot, which seeks to reduce the cost of clean hydrogen by 80% to $1 per 1 kilogram in 1 decade (“1 1 1”), which would help enable its widespread deployment and deep decarbonization. Insights into the “Hydrogen Shot” can be found in the Julie Forniciari’s interview with Department of Energy Assistant Secretary Kelly J. Speakes-Backman. In the first of two chalkboard articles, Ahmet Kusoglu presents “The Many Colors of Hydrogen” and how they define the carbon intensity of the produced hydrogen. In the second, the DOE HydroGEN Consortium team’s Shaun Alia, Dong Ding, Anthony McDaniel, Francesca M. Toma, and Huyen N. Dinh introduce the vast array of electrochemical-based hydrogen production pathways that are capable of producing clean hydrogen. In the first article of the issue, “From Hydrogen Manifesto, through Green Deal and Just Transition, to Clean Energy Act,” Plamen Atanassov, Vito Di Noto, and Stephen McPhail describe the policy steps that the European Union (EU) most recently undertook to enable wide deployment of hydrogen technologies. They also outline some of the most recent programs and projects within the EU. In the second article, “Hydrogen: Targeting $1/kg in 1 Decade,” Bryan Pivovar, Mark Ruth, Deborah Myers, and Huyen Dinh outline the landscape that is driving the need for electrolysis as an enabling tool for renewable electricity curtailment and deep decarbonization. They go on to illuminate how the low cost of renewable electrons can be captured by electrolyzers to provide a service while producing low cost H2. Finally, the DOE consortium is described, along with its agencies that are targeting research needs in this space that will help enable advances in electrolysis technology. In the third article, “PEM Electrolysis, a Forerunner for Green Hydrogen,” Kathy Ayers, Nemanja Danilovic, Kevin Harrison, and Hui Xu, present the state of the art and emerging challenges for proton exchange membrane based water electrolyzers (PEMWEs) from an industrial perspective. The authors highlight that although PEMWEs are commercially available, they are overdesigned due to their early life support applications, requiring investment in R&D at different technology readiness levels to address challenges with catalysts, membranes, and interfaces in order to meet the capital and operating cost requirements. The fourth article, by Sanjeev Mukerjee, Yushan Yan, and Hui Xu, titled “Hydrogen at Scale Using Low-temperature Anion Exchange Membrane Electrolyzers,” provides a broad overview of the materials, components, and performance status of anion exchange membrane (AEM) electrolyzers. They conclude by providing a roadmap to achieve DOE EarthShot goals. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

In the fifth article, “Hydrogen is Essential for Industry and Transportation Decarbonization,” Rod Borup, Ted Krause, and Jack Brouwer outline the challenges and pathways to decarbonization of industrial and transportation sectors and describe the role hydrogen will play to enable a net-zero carbon emissions economy. In the sixth article, “Getting Hydrogen to the Gigaton Scale,” Bryan Pivovar, Mark Ruth, Akihiro Nakano, Hirohide Furutani, Christopher Hebling, and Tom Smolinka outline the pathway for hydrogen to achieve generation on a gigaton scale, as projected by a Hydrogen Council study. Challenges to achieve this large scale of deployment consist of infrastructure development and supply chain and policy considerations. The authors further outline the R&D needs that emerged out of their ongoing Gigaton Hydrogen Workshop series that can be broadly categorized into making, moving/storing, using, and analyzing hydrogen and related technologies. The R&D advances are highlighted as most important to reach the gigaton scale of hydrogen production. In conclusion, the difference f or H2, t his t ime a round, i s t hat i t's a solution to a problem; it is no longer searching for problems to solve. In this decade, fundamental and applied science will need to come together alongside industrialization of this critical technology in order to meet society’s needs. © The Electrochemical Society. DOI: 10.1149/2.F10214IF

About the Authors Nemanja Danilovic, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. Education: BASc in Materials Engineering (University of Toronto); PhD in Materials Engineering (University of Alberta). Research Interests: Water and CO2 electrolysis. Pubs + Patents: 48 papers, h-index: 27, 3 ECS publications. Awards: ECS Toyota Young Investigator Award 2019. Work with ECS: Energy Technology Division Affiliate. Website: https://daniloviclab.lbl.gov/ https://orcid.org/0000-0003-2036-6977 Iryna Zenyuk, National Fuel Cell Research Center, University of California, Irvine, CA, U.S. Education: BS (Brooklyn Polytechnic University); MS, PhD (Carnegie Mellon University). Research Interests: Electrochemical engineering; Electrochemical energy conversion and storage; Fuel cells; Electrolyzers; Batteries; X-ray computed tomography and other characterization techniques. Pubs + Patents: 70+ journal publications, h-index: 27. Awards: ECS Toyota Young Investigator Award (2018); ECS Energy Technology Division Supramaniam Srinivasan Young Investigator Award (2021); Scialog Fellow, Advanced Energy Storage, Research Corporation for Science Advancement (2017–2019). Work with ECS: Energy Technology Division member-at-large; ECS member for 10 years Website: https://faculty.sites.uci.edu/zenyuklab/iryna-v-zenyuk/; Twitter: @muziolog https://orcid.org/0000-0002-1612-0475 41

Ten Questions for Kelly J. Speakes-Backman, Acting Assistant Secretary for Energy Efficiency and Renewable Energy, US Department of Energy questions by Julie C. Fornaciari

Hydrogen Shot is one of the Energy EarthShots coming out of DOE, why was that the first one to be released? What do you hope to accomplish besides the 1 for 1 in 1 goal? A: You are correct, the Hydrogen Energy EarthShot, announced on June 7, 2021, was the first Energy EarthShot from the US Department of Energy. All of our Energy EarthShots are based on ambitious and achievable targets focusing on key technologies, and Kelly J. Speakes-Backman while Hydrogen Shot was the first, there will be several more. All of the Energy EarthShots, focused on the remaining R&D barriers for clean energy technologies, will help us meet our ambitious 2050 net-zero carbon goals while creating jobs and growing the economy. You can learn more about the Energy EarthShot Initiative through our website.

The first two EarthShots were somewhat focused on electrochemistry. How do you see electrochemistry being the foundation for an equitable and green future for the DOE? A: Electrochemistry can provide wide-ranging societal benefits across many sectors and applications, including energy storage and conversion technologies, advanced manufacturing and chemical synthesis methods, and waste, water and soil management and remediation. These advanced technologies can help reduce environmental impacts and improve public health for disadvantaged communities located near industrial clusters, as well as improving energy efficiency, creating jobs, and providing safe, affordable, and reliable energy. To learn more about DOE’s engagement with electrochemistry in manufacturing, see our recent virtual webinars on this topic.

What is DOE’s strategy for moving green hydrogen production out of national and academic labs and into production at the MW-GW scales? A: Through our DOE Hydrogen Program, we are leading and supporting a number of programs and industry consortia focused on clean hydrogen production, both in the early R&D and piloting phases and in demonstration and large-scale infrastructure projects. Identifying opportunities for cost-effective and large-scale clusters of production and demand applications can help achieve economies of scale, which is key to reducing costs, building institutional capacity, and accelerating learning-by-doing To learn more about the specific areas the DOE Hydrogen Program is working on to accelerate clean hydrogen progress, refer to the DOE Hydrogen Program Plan. The Hydrogen Shot builds on these and other activities by convening stakeholders to develop regional plans for large-scale, near-term clean hydrogen deployments. Examples of relatively 42

new industrial consortia, funded by the DOE Hydrogen and Fuel Cell Technologies Office, include the Million Mile Fuel Cell Truck Consortium, the HyBlend project for blending hydrogen with natural gas, and Hydrogen from Next-generation Electrolysis of Water, H2NEW. Information on H2@Scale, which articulates DOE’s conceptual framework for the future of hydrogen energy, including reports and funding opportunities, can be found on the H2@Scale website.

Hydrogen alone can’t solve all our climate change issues, but what is its unique role? What advantages do you see in green hydrogen within the energy landscape? A: One of hydrogen’s unique contributions to decarbonize is the ability to deliver lowcarbon energy to end-use applications that are economically challenging to electrify. We refer to these as “hard to decarbonize” sectors. These include medium- and heavyduty vehicles; rail, marine, and aviation applications; iron and steel refining; bulk chemical production; and cement production. Hydrogen can also be used as long duration energy storage to help decarbonize the future electricity grid when relying upon variable production sources like wind and solar. Check out the recent blog “How Wind Energy Can Help Clean Hydrogen Contribute to a Zero-Carbon Futureˮ from our Wind and Hydrogen and Fuel Cell Technologies Office on how hydrogen can enable offshore wind.

The Hydrogen Shot goal ($1 per kg in 1 decade) is mainly based on production; how do you see the need for hydrogen storage, transportation, and use to meet the overall climate goals? A: Once clean hydrogen is produced, it will typically be stored and transported in some manner to an end-use application. There are many different methods of hydrogen storage, transmission, and distribution—the most efficient and cost-effective methods depend on the volume of hydrogen produced, the delivery distance, and the particular end-use application.

How is DOE attempting to educate the greater public on these Energy EarthShots and hydrogen production? Most constituents associate hydrogen with “flammable” or “combustible.” How do you plan to change the narrative? A: Hydrogen is actually not a new fuel. It has been used in industrial applications like petroleum refining and fertilizer production for many decades with a strong track record on safety. Today we use ~10 million metric tons of hydrogen per year, and we have over 500 MW of stationary fuel cell installations for back-up power in the US. Just like gasoline, natural gas, or any other fuel, hydrogen is combustible and needs to be handled carefully with appropriate safety protocols. DOE has been working for many years with a broad network of international industrial and governmental stakeholders to develop codes and standards for new applications like vehicles The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

and stationary fuel cells in buildings. The success of these efforts can be seen in the many public refueling stations in operation across the country, especially in California, as well as in applications like fuel cell forklifts in warehouses, public transit buses in cities, and stationary backup power in hospitals, data centers, commercial buildings, and cell phone towers. The safety of future applications using clean hydrogen will be ensured through the same processes and institutions used to develop protocols and codes and standards used in today’s applications. As people see more of these technologies in their communities, they will see that hydrogen is as safe as our other fuels. An example of our international involvement is the Center for Hydrogen Safety through the American Institute of Chemical Engineers (AIChE).

The Hydrogen Shot strives to reduce environmental injustices, but what are concrete ways DOE and other agencies are planning to mitigate inequities? What is the DOE’s vision in utilizing green hydrogen and other energy technologies toward environmental justice goals? A: One example of how hydrogen in particular can contribute is to eliminate tailpipe emissions from gasoline and diesel trucks through the introduction of zero-emission fuel cell trucks. This will reduce particulate and other criteria emissions along highway corridors and within ports and industrial clusters located near disadvantaged communities. The principles of environmental justice are applied across all the DOE’s programs, policies, and activities. This includes staff training as well as community engagement through the Site-Specific Community Advisory Boards for DOE cleanup decisions, and the annual National Environmental Justice Conference and Training Program. More information on the history and implementation of Environmental Justice at DOE can be found on our Environmental Justice website.

The clean energy jobs that will result from the Hydrogen Shot, who do they target? High-school educated, college educated, or advanced degrees? Are there plans for investing in electrochemistry undergraduate programs? Will the jobs they replace be equivalent roles? Better yet, how does the program plan to re-educate the workers for these new jobs? A: An important element of the Hydrogen Shot initiative is to ensure we have close engagement with all stakeholders that could be affected by the deployment of hydrogen technologies, which could include workforce in coal, gas, and petroleum industries. Additionally, we have an existing education outreach program, the Hydrogen Education for a Decarbonized Global Economy, H2EDGE, which is working with universities and other training institutions to build a bench of skilled and talented workforce to support the emerging hydrogen industry.

ORCID

Connecting research and researchers

Hydrogen Shot is a big undertaking; how do you see organizations like ECS and other societies helping achieve these goals? A: We know the only way we can achieve Hydrogen Shot is by bringing together all the resources, brain power, and tools to push the envelope in next-generation technologies that can cheaply produce, store, transport, and utilize clean hydrogen. That includes engaging and collaborating with organizations like ECS, among others. Here are a few resources: • Attend our annual Hydrogen Shot Summits—the first one just took place on August 31–Sept 1 but recordings will be posted on Hydrogen Shot Summit | Department of Energy • Sign up for our newsletter to get updates on upcoming events, funding opportunities and requests for information • Celebrate Hydrogen and Fuel Cell Day on 10/08, a day of activities and announcements matching hydrogen’s atomic weight of 1.008

Why are you excited for these initiatives? Do you

personally have a connection to electrochemistry, clean energy, or environmental justice? Or is hydrogen just your favorite element? A: I am excited about all of the clean energy technologies we are investing in at DOE, including hydrogen, because I know they are all key pieces to ensure we can reach President Biden’s bold goal of achieving net-zero carbon emissions by 2050 and an equitable and clean energy future for all. © The Electrochemical Society. DOI: 10.1149/2.F11214IF

About the Author Julie C. Fornaciari, University of California, Berkeley & Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. Education: BS Chemical Engineering (University of Pittsburgh), PhD candidate in Chemical Engineering (University of California, Berkeley) Research Interests: Electrochemistry, Hydrogen production, Energy conversion Pubs + Patents: 12 papers (5 in ECS journals), 20 presentations, h-index: 4 Awards: LBNL SPOT Award for Recognition of Excellence to the LBL’s Workforce Development & Education Programs (2021); NSF Graduate Research Fellowship Program (2017) Work with ECS: Student member since 2018 https//orcid.org/0000-0002-0473-2298

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

d r a o b k l a h C e Th #1

The Many Colors of Hydrogen by Ahmet Kusoglu

Frequency of Hydrogen Production pathways mentioned with or without colors in Energy Roadmaps and Hydrogen Reports 1

Pathway Total number of mentions in recent hydrogen roadmaps The last few years have given rise to an increased number of energy roadmaps and pledges by many countries committed to reducing emissions of greenhouse gases (GHGs), and to achieving net-zero emissions accord with the Paris Agreement that aims to limit Black /in Brown Pathway mentioned with Color (filled)global a warming to 1.5°C, compared to pre-industrial levels. The most recent Intergovernmental (IPCC) notes PathwayChange mentioned withoutreport colors (open) (Gasification, Coal) Panel on Climate that global warming is likely to reach 1.5°C between 2030 and 2052 if it continues at its current rate.1 To limit and stabilize the long-term Gray / Grey temperature increase, the recent International Energy Agency (IEA) and IPCC reports stress the need for achieving carbon-neutrality by (SMR, Natural Gas) various technological advances for decarbonizing 1-3 2050. Achieving this transformation requires a series of policies and efforts involving Blue (SMR +CCUS,for decarbonization pathways.2-28 A recurring theme many sectors, as outlined in many recent roadmaps providing a comprehensive analysis Carbon in these roadmaps is the pivotal role of hydrogen and its potential to helpw/ steer the Capture) world toward achieving and realizing the decarbonization pathways (Fig. 1). Green (Electrolysis

Hydrogen is not an energy source; it is a versatile, colorless, molecular energy vector that can be produced, stored, and delivered for end-use for many key sectors, from construction and industry to transportation. Hence, hydrogen is a distinctive molecular enabler that can energize and electrify hard-to-decarbonize sectors. In recent energy reports, hydrogen demand projections for 2050 vary from 18 to 86 EJ2,6,12,21,26,b and exceed 175 EJ in more ambitious scenarios,4,26 which amounts to 16 to 24% of the world’s final energy demand in 2050,4,6,16,17,21 with an economy and investment of $2.5 to 11 trillion.4,6,11,12,17 Hydrogen production in 2050 is projected to exceed 60 million Mt (MMt) in the US,17 and could reach a range of 500 to 800 MMt globally, depending on the scenario and analysis.2,4-6 With such projected demand comes the need to produce hydrogen, Frequency of Hydrogen Production pathways mentioned with or without colors in Energy Roadmaps and Hydrogen Reports 1 Pathway

Total number of mentions in recent hydrogen roadmaps

Black / Brown (Gasification, Coal) Gray / Grey (SMR, Natural Gas) Blue (SMR +CCUS, w/ Carbon Capture) Green (Electrolysis from renewables) Turquoise (Methane Pyrolysis) Yellow (Electrolysis from mixed grid) Pink / Red (Nuclear) Biomass Pathways Other Advanced & “Solar” Pathways

Pathway mentioned with Color (filled) Pathway mentioned without colors (open)

from renewables) Turquoise (Methane Pyrolysis) ultimately at large scales and with minimal environmental impact Yellow (Electrolysis and GHG emissions. Achieving this goal is the primary driver behind from mixed grid) many of the hydrogen vision plans, such as the US Department of Pink / Red(DOE) Hydrogen EarthShot,c which aims to reduce the cost Energy’s of(Nuclear) clean hydrogen by 80% to $1 per 1 kilogram in 1 decade (“1 1 1”). Hydrogen is the simplest element consisting of one proton and Biomass one electron, which it an energy carrier suitable for many reactions Pathways in thermochemical, bio-chemical, and (photo)electro-chemical, Other Advanced & processes. For example, a DOE report defines hydrogen as “an energy “Solar” Pathways carrier that is produced using energy and feedstocks such as water,

biomass, natural gas, oil, coal, and wastes such as wastewater and 1 Compiled by analyzing the content for the use of pathway and colors in over 20 15 plastics,” which captures breadth ofsingle/multiple the sources and technology reports from the last 4 years, the which includes reports published d pathways beyond the currently used matureFCHEA, industrial processes. by the IEA, IRENA, Hydrogen Council, McKinsey, Rhodium Group, BNEF, Shell, RMI, NACFE, ‘European Union (FCH joint undertaking), Germany, Canada, Japan, Korea, California, and the U.S. Department of Energy. 2 Each box denotes the mention of pathway in a study, regardless its frequency.

Google Trends: “Color Hydrogen”

Search Interest over the last 5 years (100 = highest)

100

Average in last 6 months 0 50

Blue Hydrogen

Green Hydrogen

Gray Brown Hydrogen

2017

2019

2021

1 Compiled by analyzing the content for the use of pathway and colors in over 20 reports from the last 4 years, which includes single/multiple reports published by the IEA, IRENA, Hydrogen Council, McKinsey, FCHEA, Rhodium Group, BNEF, Fig. 1.Shell, Left:RMI, Summary of mentions of hydrogen production pathways NACFE, ‘European Union (FCH joint undertaking), Germany, Canada, with a color assignment (filled box) or without a color assignment (open box) in Korea,reports California,and and the U.S. Department of Energy. recent Japan, hydrogen energy roadmaps covering hydrogen.2-26 Each box represents the existence of one unique document that defines or discusses 2 Each boxpathway, denotes theregardless mention of pathway in a study, regardless its frequency. a particular of its frequency in the report. Right: Timeline shows the changes in search interest on the web for three “hydrogen

colors” (from GoogleTrends) over the last 5 years (100=highest). Google Trends: “Color Hydrogen”

Search Interest over the last 5 years (100 = highest)

100

Average in last 6 months 0 50

Green Hydrogen

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

This article cannot cover all the aspects and nuances that the topic of hydrogen highly deserves; it aims to provide a concise introduction to the production pathways discussed in this Interface issue and clarify some relevant concepts to inform future studies. Hydrogen production pathways involve conversion from a primary energy source through thermochemical, biochemical, electrochemical, photochemical, or biological processes. Figure 2 summarizes the different pathways that include existing (mature) and advanced technologies. Each pathway comes with a certain level of carbon (dioxide) emitted to the atmosphere. This pathway-emission fingerprint of hydrogen is not only an essential component of analysis of clean-energy transitions and policies, but it is also ingrained in a hydrogen molecule’s DNA throughout its supply chain and utilization, as characterized somewhat arbitrarily by a color-code. A survey of 25 reports on hydrogen plans and energy roadmaps from the last three years unraveled a rainbow of colors for numerous pathways, albeit to a varying extent (Fig. 1). Currently, the pathways and some of the associated colors of hydrogen are defined based on a combination of three intertwined factors: (1) The technology and the conversion process (e.g., thermo/ photo/bio/electro-chemical reactions, used to produce the hydrogen). (2) The amount of carbon emitted during these processes (e.g., gray vs. blue depending on the extent to which carbon is captured vs. emitted). (3) The source of the energy (electricity) that powers the process, especially for electrolysis: green for hydrogen from renewables, red from nuclear, and yellow from other nonrenewable sources or mixed grid. As of 2021, most hydrogen is produced by thermochemical processes: gasification and reforming, with designated colors of black/ brown and gray, respectively. Such processes are in direct contrast to all of the other processes, which are considered “clean.” Gasification is the process of converting coal or carbonaceous material at high temperatures into gases, which are then reacted with steam to separate the H2. There are three reforming methods: steam methane reforming (SMR), partial oxidation (PO), and autothermal reforming (ATR).18 Currently, SMR is the dominant method responsible for >75% of hydrogen production.18 Simply put, SMR reacts methane (CH4) with high-temperature steam (700–1000°C) in the presence of a catalyst to produce syngas, or synthesis gas, a mixture of H2 and CO: (1) SMR is followed by water-gas shift reaction (WGSR) of syngas to produce more H2. PO uses oxygen in the air as the oxidant, whereas ATR is a combination of SMR and PO and employs oxygen instead of air. The carbon intensity of these processes is 9–10 kgCO2/kgH2 for SMR, and 19–20 kgCO2/kgH2 for coal gasification.18-21 It must be noted that these emission levels are already much lower compared to the CO2 intensity of burning fossil fuels, or that of electricity generation with the respective fossil fuel source. However, it is possible to further reduce these carbon emissions, using carbon capture and utilization (CCUS) methods. For example, a capture rate of 80–90% could be achieved for SMR with CCUS and even higher rates could be achieved with autothermal reforming.15,18,19,21 For example, according to an IEA analysis, the CO2 intensity of hydrogen production from natural gas drops from ~9 to below 2 kgCO2/kgH2 with a CCUS capture rate of 90%, as compared to ~17 kgCO2/kgH2 emissions from gas-fired electricity.18 The blue color is assigned to low-carbon hydrogen produced from fossil-sources with carbon sequestration. Another low-carbon thermochemical process is methane pyrolysis, a process of gasification in the absence of oxygen that generates so-called turquoise hydrogen and yields solid carbon residue, thereby significantly mitigating CO2 release to the atmosphere. With the expected increase in global demand for carbon black or higher-value carbons (e.g., nanotubes) and existing infrastructure for transporting methane, methane pyrolysis could be a viable option for clean hydrogen production.18 Overall, due to its existing prevalence, blue hydrogen is a key short-term and

perhaps long-term solution for clean hydrogen and as a low-carbon alternative to gray hydrogen.2,4,6,7,13-16,19,21 Thus, it is not surprising that gray, blue, and green are the most frequently mentioned colors, with green becoming increasingly popular, which is reflected in the internet interest in hydrogen colors (Fig. 1). Another conceivable, prevalent, and existing pathway for hydrogen is as a by-product of industrial processes (methane pyrolysis could also perhaps be considered such a by-product, depending on the value of the carbon). Currently, most by-product hydrogen is from chloralkali electrolysis in the production of chlorine and caustic soda; it accounts for 2% of global H2 production, compared to 0.1% from water-splitting electrolysis with renewables.18-20 One could assign colors based on the energy source of the process in the chemical industry, but another rare practice is to assign the color white. The rest of this article focuses on so-called dedicated hydrogen pathways, as tabulated in Fig. 3. Although there is consensus on the color of high-carbon hydrogen (black/brown/gray), the same is not true for the zero-carbon or even carbon-negative pathways. Part of this stems from the discrepancy between the more mature technologies with large-scale industrial demonstrations and the advanced pathways that are in early stages of R&D. For example, almost all reports discuss nuclear mainly as the electricity source for (low-temperature) electrolysis, yet ongoing research includes nuclear heat for high-temperature electrolysis (Fig. 2).15,18,19 For this reason, many advanced pathways are discussed without a strong color association; in particular, the promising biomass and direct-solar pathways. The most commonly discussed low/ zero-carbon pathway is electrolysis, which separates water molecules using electricity to generate hydrogen and oxygen. If the source of electricity is from renewables (e.g., solar or wind), then the hydrogen is commonly defined as green, while hydrogen from a grid of mixed sources is sometimes defined as yellow. When fossil-fuel sources are used to generate electricity for electrolytic (yellow) hydrogen, the emission values could be comparable or even higher than gray hydrogen.18,19 Because electrolytic hydrogen can be produced using many distinct pathways, identifying its carbon impact is not trivial, which adds a level of uncertainty to color-coding. For example, according to Bloomberg New Energy Finance (BNEF), 17GW of electrolyzers are planned for commissioning by 2030, yet the majority of them have not detailed the electricity source, nor the electrolyzer technology, meaning a color cannot be assigned.5 In a limited number of studies, red is reserved for electrolytic hydrogen with electricity from nuclear. Biomass pathways have been discussed only in select reports, with examples on biomass gasification with CCUS, bioreforming, or biomass conversion, some within the context of even negative carbon emissions.2,9,15,18 Electrolysis requires water, in addition to electricity. Producing 1 kg of H2 via electrolysis requires 9 liters of H2O, which creates 8 kg of O2 as by-product. According to a hydrogen report by IEA,18 producing all the dedicated hydrogen needs of world via electrolysis would require 617 million cubic meters of water, corresponding to over 1% of water consumption of the global energy sector or twice the current water consumption for hydrogen from SMR. Other analyses also concluded that water will not pose an important resource constraint or environmental stressor for electrolysis.29,30 Because water is already used (in liquid or steam form) in other thermochemical pathways (e.g., reforming) and in industrial processes that generate dedicated or by-product hydrogen, its role must be assessed and evaluated accordingly in a broader context. Green hydrogen usually designates that produced via electrolysis with zero-carbon electricity. However, green hydrogen from watersplitting can also be produced through direct-solar pathways, without use of grid electricity, such as photoelectrochemical (PEC) hydrogen, solar thermochemical hydrogen (STCH), or photobiological processes (microorganisms) (Fig. 3 and Fig. 4). PEC production uses photoelectrodes that generate charge carriers from solar irradiation, which drive chemical water-splitting reactions and produce hydrogen (continued on next page)

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Kusoglu

(continued from previous page) INDUSTRIAL METHODS BIOMASS PATHWAYS THERMOCHEMICAL PATHWAYS

Industrial By-product

Fossil Fuel Resources

Nuclear

agricultural or solid waste, organic residue

Hydro

Solar PV

Wind

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Solar STCH

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 Water Reserves e-

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biogas

ol Bi m

high carbon emissions

carbon captured and stored (CCS)

high carbon emissions

g in

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r fo

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a ic

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oBi

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Electricity generation with carbon emissions

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Industrial Chemical Processes

process emissions

Biomass

Petroleum Products Coal, Natural gas (NG)

Chemical Products

White Hydrogen

Emissions

SOLAR PATHWAYS

ELECTROLYTIC PATHWAYS

Turquoise Hydrogen yields solid carbon residue

Bio-gas Hydrogen

Bio-mass Hydrogen

low-carbon with CCUS or negative / zero emissions

Pink / Red Hydrogen

Yellow Hydrogen

Green Hydrogen

near-zero H2 low-carbon H2 zero-emission from nuclear power electricity emissions renewable electricity

Direct Solar Water-splitting Solar Photo-Electro Chemical (PEC) watersplitting

Solar Thermo-Chemical water-splitting Hydrogen (STCH)

PhotoBiological watersplitting

Green Hydrogen

net-zero emissions

low to net-zero emissions

LOW- CARBON / CLEAN HYDROGEN THE R M OC HEM IC AL CON V ER SION HYDROGEN PRODUCTION FROM FOSSIL FUELS AND FEEDSTOCKS Not a dedicated hydrogen production pathway

Gasification

Reforming, SMR

3C solid + O2 + H2O H2 + 3CO

CH4 + H2O  3H2 + CO

CO + H2O  CO2 + H2

CH4 + H2O  3H2 + CO CCUS

BIOCHEMICAL CONVERSION

Pyrolysis

Dark Fermentation: Microrganisms consume CH4  2H2 + C solid and break down organic CCUS matter and release hydrogen

EL EC TRO CHEMI C AL CO NVERSI O N ELECTROLYTIC HYDROGEN Splitting water molecules with electricity to generate hydrogen: H2O + (nuclear) electricity  H2 + ½O2 H2O + (mixed-grid) electricity  H2 + ½O2 H2O + (zero-carbon) electricity  H2 + ½O2

DIRECT SOLAR THERMOCHEMICAL WATER-SPLITTING WATER-SPLITTING Photo-ElectroChemical devices split water using sunlight to produce hydrogen gas

Uses high temperatures from concentrated solar and chemical reactions to produce hydrogen

PHOTOBIOLOGICAL Microorganisms consume water in the presence of sunlight to produce hydrogen gas

Fig. 2. Illustration of hydrogen pathways and associated colors (bottom boxes) based on the conventional assignment. The diagram includes both mature technologies that represent the majority of the hydrogen production today and emerging technologies for producing low-carbon or clean hydrogen as well as advanced pathways (open boxes) for carbon-neutral or carbon-negative hydrogen that are in early stages of R&D—as of the time of the publication of this article. Despite the variations in colors for some processes or their lack thereof, electrolytic, solar, and bio-mass pathways offer the prospect of clean hydrogen.

and oxygen. STCH utilizes concentrated solar energy to reach high temperatures and split water via coupled chemical cascades composed of redox and chemical steps; STCH is a closed-loop process that consumes only water and produces hydrogen and oxygen. Similarly, biochemical pathways such as microbial biomass conversion using waste streams could also yield hydrogen with zero-emissions. Thus, a more inclusive definition for green hydrogen would encompass water-splitting, which could be electrolytic or direct-solar, as well as bio-pathways (Fig. 4). In fact, the latter includes technologies that could potentially be carbon-negative, meaning a net decrease in the carbon emissions. Thus, electrolysis with renewables is just one of the many pathways to split water. For example, a recent report reviewing the state policies on electricity, renewable, and zero-carbon resources in California by 2045 mentioned explicitly the green electrolytic hydrogen.10 Thus, with the renewed interest in hydrogen production and increased attention to exploration of advanced pathways toward carbon-neutral or carbon-negative hydrogen as tabulated in Fig. 3, the color designations are likely to be refined. In addition, of all the electrolytic pathways, most reports tend to focus disproportionately on low-temperature electrolysis (LTE) due to its flexibility and operability with variable inputs, yet some advanced pathways such as high-temperature electrolysis (HTE) and STCH are highlighted for their efficiency.2,15,18 Thus, the future of integrated hydrogen production methods could be a mix of processes to increase the efficiency of electrolysis using high-temperature steam from nuclear power plants or industrial processes.2,6,15,18

Biomass pathways include biomass gasification; conversion of biomass to H2 and other products using heat, steam, and oxygen without combustion; as well as biomass-derived liquid reforming, which converts biomass to liquid biofuels (e.g., ethanol) to be transported to the point of use and reformed to produce H2, similar to natural gas reforming. These processes also offer the prospect of producing low-carbon or even carbon-negative hydrogen. For example, California discussed hydrogen and biomass pathways as part of their roadmap to net-zero as well as negative carbon emissions.8,9 Thus, there are many potential roads to clean hydrogen, and commercializing certain pathways with negative emissions could even reduce the carbon budget, going beyond zero-carbon hydrogen. During the ongoing clean energy transition, there will likely be a mix of complementary pathways, and therefore a hydrogen “rainbow.” For example, Fig. 5 shows the current and projected future hydrogen-production portfolio, exhibiting a transition to clean hydrogen.2,19 According to the recent IEA report, in a net-zero scenario by 2050, hydrogen production is almost entirely based on low‐carbon technologies with water electrolysis accounting for >60% of global production, and natural gas in combination with CCUS accounting for almost 40%.2 This scenario is in conjunction with the expansion of global hydrogen use from ~90 Mt in 2020 to 212 Mt in 2030 and to >500 Mt by 2050.2 Consequently, the production color of H2 dyes the products it enables (e.g., green ammonia or green steel), the legislation it drives, and even the policies in which it plays a major role (e.g., green

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Consumption of water by microorganism, such as green algae, in the presence of sunlight to produce by-product H2



Zero emissions



Hydrogen from water splitting reactions driven by the energy harvested from sunlight using photoelectrodes

Zero Emissions



Low-Temperature Electrolysis (LTE)

Emissions from electricity source Low with CCUS Zero emissions

Solar Thermo-Chemical Hydrogen (STCH)

Sunlight

Photo-electrochemical (PEC)

Water



Low-to-Zero emissions

Solar Heat Water

Electricity

Zero-to-negative emissions

Hydrogen from water splitting via chemical reactions at high temperatures driven by solar concentrators

Electrochemical splitting of water using electric current to generate H2 below 100˚C (e.g. in membrane-based systems) High-Temperature Electrolysis (HTE)

Solid-oxide electrolyzers generate H2 from water (steam) by using heat at elevated temperatures (400 - 850˚C)

HighTemperature Electrolysis (HTE) H2

scenario). In several major reports laying out the net-zero pathways toward 2050, hydrogen has emerged as a key player in the final energy mix. For example, the recent energy outlook by BNEF6 color-coded net-zero pathway scenarios as green, red, and gray, with the “green scenario” involving the most use of green hydrogen complementing electricity use and bioenergy, and the “red scenario” benefiting from nuclear, and with both yielding a hydrogen consumption of 766 MMt by 2050.6,d A decarbonization report by the Hydrogen Council also poses color-coded hydrogen scenarios where “green-only” and “blue-only” correspond to a renewables-based world versus a world that relies on carbon sequestration, compared to the current “gray” hydrogen supply pathways.12 Other agencies have published roadmaps with conceptually similar comparisons of base versus more ambitious or aggressive scenarios, but not always with direct color associations, despite the frequent use of green in a broader context.3,8,16,17,26,27 The increased popularity of colors due to simplified associations with pathways-emissions is merely a testament to the momentum hydrogen has been gaining in recent years (Fig. 1). Any limitations of the conventional hydrogen color scheme do not necessarily require a call for the abandonment of the concept, but should rather be seen as an opportunity to continue the broader conversation to support the development, scale-up, and deployment of new technologies and advanced pathways for decarbonizing hydrogen production. The long-term realization of advanced pathways that are currently in the R&D stage along with the decarbonization of existing processes could result in refinement or an expanded definition of colors, if they remain in use. The emergence of low-carbon hydrogen, along with its potential for realizing carbon-neutral as well as carbon-negative technologies, call for a new perspective on hydrogen colors with an emphasis on the carbon intensity of the processes and associated definitions (Fig. 3). For example, in recent US legislation,f the term “clean hydrogen” is defined as hydrogen produced with a carbon intensity ≤ 2 kgCO2-equivalent/kg(H2). Overall, with the ongoing transition to a green energy paradigm, the hydrogen production concept will likely converge from a dynamic

H2O

Grid

Low-Temperature Electrolysis (LTE) I M

(ZE YS WA H ELEC T R T A OLYSIS P



Wind

Heat



Fig. 3. Summary of dedicated hydrogen production methods listed based on emissions impact along with technology pathways. Carbon intensity is shown as a ranked category order—negative, zero, low and high—to qualitatively define low-carbon and zero-carbon hydrogen.

)

Water



H2O

CIT Y

Sunlight

Photo-biological

Microorganisms consume, digest and break down organic matter and release H2 (e.g., “dark fermentation”)

Low-to-negative with CCUS

Solar thermochemical water- H2 splitting (STCH)

TRI

Microbial Biomass Conversion



Biowaste Organic matter

Water

ELECTROLYTIC

Biomass Conversion

Biomass Gasification to H2 at high temperatures, or, Reforming Biomass-Derived Liquids to hydrogen

Zero Emissions

Biomass Solid waste, Organic resource

Gasification of methane in the absence of oxygen, which yields solid carbon residue



Photo-electro chemical (PEC) water-splitting direct from sunlight

electrolysis (e.g., Algae)

Methane Pyrolysis



High Low with CCUS

Natural Gas Methane

SMR: Steam (methane) reforming (700-1000˚C) PO: Partial Oxidation, ATR: Autothermal Reforming



RMOCHEMICAL, PHOT ( THE O-B YS IOL A OG HW T H2 IC PAPhotobiological AL R , A

Reforming



High Low with CCUS

SO L

Natural Gas Methane

Converting coal at high temperature into syngas, which is further reacted with steam to produce H2

Carbon Intensity

Negative Zero Low High

Process and Description Gasification

CESSES RE PRO ATU R E MP TE HG HI

BIOMASS DIRECT-SOLAR

Source Coal, Lignite Fossil-based materials

ICAL) CHEM TRO LEC OE OT PH

THERMOCHEMICAL

H Y D R O G E N P R O D U C T I O N P AT H W AY S

-E

Fig. 4. Pathways for clean (“green”) hydrogen based on either directsolar water-splitting or electrolytic water-splitting using zero-carbon electricity, which includes electricity generated from solar.

Hydrogen Production 2020 2030 Hydrogen (no CCUS) 5%

95% Gray/Black H2 fossil-based production

2050 Low Carbon with CCUS

Low Carbon Electrolytic

70% Low-Carbon CCUS + Electrolysis

Low Carbon Zero-Carbon “Blue” H2 Electrolytic “Green” H2

98% Low Carbon

of which 62% Electrolysis

Electrolyzer Capacity < 1 GW

850 GW

3585 GW

Notes: areprojected based on Net-Zeroproduction Emission scenario IEA Fig. 5.Projections Current and hydrogen sorted byby technology * There is also by-product hydrogen fromtoChlor-Alkali electrolysis pathway (color). The total size is proportional the total production volume. For 2050 projections, the majority of the production is clean Source: IEA (2021) hydrogen, and the small patterned slices represent the electrolysis-based low-carbon hydrogen from nuclear power and fossil fuels with CCUS. The values are taken from the IEA Net-Zero by 2050 report.2

color palette that transcend colors with varying degrees of gradients reflecting the energy sources and technologies to a distilled color palette that can be used to paint a cleaner future. With its existing ties to industrial processes and promising coupling with grid, renewable sources, and biomass, adaptability for centralized and distributed uses, and ability to blend with natural gas, hydrogen is enjoying a growing enthusiasm surrounding and recognizing its role as the (continued on next page)

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Kusoglu

(continued from previous page)

flexible energy currency of the future. It is this convertibility of hydrogen among processes that has endowed this colorless molecule with the ability to help put the world on track for the required clean energy transformation and to achieve global climate goals.

Acknowledgment The author acknowledges funding from the Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cells Technology Office (DOE-EERE-HFTO) under contract number DE-AC02-05CH11231. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. © The Electrochemical Society. DOI: 10.1149/2.F12214IF

About the Author Ahmet Kusoglu, Staff Scientist, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. Education: PhD (University of Delaware), Post-doctoral research at LBNL Research Interests: Ionomers, Polymer electrolytes and interfaces, Mechanoelectrochemistry, Structure-property relationships, Hydrogen fuel cells and electrolyzers, Data science and visualization, Data-driven material design. Pubs + Patents: >70 peer-reviewed journal papers, 2 book chapters, >30 invited talks and tutorials at international meetings, academia, and industry forums. Work Experience: Scientist and Principal Investigator working on ionomers and membranes for hydrogen fuel cells and electrolyzers; Communications officer Million Mile Fuel Cell Truck (M2FCT) Consortium. Awards: ECS Energy Technology Division's Srinivasan Young Investigator Award and ECS Toyota Young Investigator Fellowship. Work with ECS: ECS member for 10 years; Member-at-large, Energy Technologies Division (ETD), past member and chair of the ETD awards committee; Member of organizing committee for Polymer Electrolyte Fuel Cells and Electrolyzers (PEFC&E) symposium. Website: https://kusoglulab.lbl.gov https://orcid.org/0000-0002-2761-1050

Notes https://www.ipcc.ch/sr15 (Intergovernmental Panel on Climate Change) b 1 EJ is the amount of energy produced globally every ~14 hours, as of 2021 (https://www.iea.org/world) c https://www.energy.gov/eere/fuelcells/hydrogen-shot d https://www.energy.gov/eere/fuelcells/hydrogen-production e https://about.bnef.com/new-energy-outlook f US Congress HR3684, “Infrastructure Investment and Jobs Act.ˮ a

References 1. V. Masson-Delmotte, P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou, “IPCC - Climate Change 2021: The Physical Science Basis.” Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC (2021). 2. International Energy Agency (2021), Net Zero by 2050: A Roadmap for the Global Energy Sector, (2021) IEA, Paris. 3. World Energy Outlook, International Energy Agency (IEA) (2020). 4. Hydrogen Economy Outlook, BNEF (2020). 5. Tracking the Hydrogen Economy, BNEF (2021). 6. New Energy Outlook, BNEF (2021). 7. Clean Hydrogen: A Versatile Tool for Decarbonization, Rhodium Group (2021). 8. Getting Neutral: Options for Negative Carbon Emissions in California (2020). 9. Achieving Carbon Neutrality in California, CARB (2020). 10. SB 100 Joint Agency Report: Charting a path to a 100% Clean Energy Future, California Energy Commission (2021). 11. How hydrogen empowers the energy transition, Hydrogen Council (2017). 12. Hydrogen Decarbonization Pathways, Hydrogen Council (2021). 13. Hydrogen Insights Report, Hydrogen Council, McKinsey & Company (2021). 14. The National Hydrogen Strategy, German Federal Government (2021). 15. DOE Hydrogen Program Plan, U.S. Department of Energy (DOE) (2020). 16. Hydrogen Roadmap EUROPE, EU Fuel Cells and Hydrogen Joint Undertaking (2019). 17. Road Map to a US Hydrogen Economy, FCHEA (2020). 18. The Future of Hydrogen, International Energy Agency (IEA) (2019). 19. Hydrogen Tracking Report, International Energy Agency (IEA) (2020). 20. Hydrogen: A renewable energy perspective, IRENA (2019). 21. Green Hydrogen: A guide to policy making, IRENA (2020). 22. The Strategic Road Map for Hydrogen and Fuel Cells, Japan (2019). 23. How Industry Can Move Toward a Low-Carbon Future, McKinsey & Company (2018). 24. Making Sense of Heavy-Duty Hydrogen Fuel Cell Tractors, NACFE (2020). 25. Hydrogen’s Decarbonization Impact for Industry, Rocky Mountain Institute (2020). 26. Sketch: A US Net-Zero CO₂ Energy System by 2050, Shell (2021). 27. J. H. Williams, R. A. Jones, B. Haley, G. Kwok, J. Hargreaves, J. Farbes, and M. S. Torn, AGU Advances, 2, e2020AV000284 (2021). 28. J. S. Davis, N. S. Lewis, M. Shaner, S. Aggarwal, D. Arent, L. Azevedo Inês, S. M. Benson, T. Bradley, J. Brouwer, Y.M. Chiang, C. T. M. Clack, A. Cohen, S. Doig, J. Edmonds, P. Fennell, C. B. Field, B. Hannegan, B.-M. Hodge, M. I. Hoffert, E. Ingersoll, P. Jaramillo, K. S. Lackner, K. J. Mach, M. Mastrandrea, J. Ogden, P. F. Peterson, D. L. Sanchez, D. Sperling, J. Stagner, J. E. Trancik, C.-J. Yang, and K. Caldeira, Science, 360, eaas9793 (2018). 29. Hydrogen Production & Water Consumption, Hydrogen Europe (2021). 30. R. R. Beswick, A. M. Oliveira, and Y. Yan, ACS Energy Lett, 6, 3167 (2021).

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How to Make Clean Hydrogen

d r a o b k l a h C e Th #2

AWSM: The Advanced Water Splitting Materials Consortium by Shaun Alia, Dong Ding, Anthony McDaniel, Francesca M. Toma, Huyen N. Dinh

Clean hydrogen is a carbon-free energy carrier that can be produced from water and sustainable energy sources such as wind, solar, and nuclear. Hence, clean hydrogen is one of the best ways to not only decarbonize the energy supply system, but also address the zero-emission challenges specific to large-carbon emitting industries that are difficult to separate from fossil fuels (e.g., heavy-duty trucking, load-following electricity, iron, steel, and cement). To help achieve the Biden Administration’s goal of a 100% clean energy economy and net-zero emissions by 2050, several tens of millions of metric tons of clean, low-cost hydrogen will be needed annually. The U.S. Department of Energy (DOE) recently launched the Hydrogen Energy EarthShot (“Hydrogen Shot”) which aims to reduce the cost of clean hydrogen to $1 per 1 kilogram in 1 decade.1 H2@Scale (Fig. 1) is a DOE initiative that supports the Hydrogen Shot goals to enable drastic decarbonization by scaling up low-cost clean hydrogen production, transport, storage, and utilization.2 Clean hydrogen can power the grid, generate heat, be stored as an energy carrier, and be used to decarbonize multiple industrial sectors that are currently major contributors to carbon dioxide emissions. Some examples of these sectors are transportation, ammonia/fertilizer production, synthetic fuels, metal refining, and chemical/industrial processes. In summary, large-scale, low-cost hydrogen production from diverse domestic resources can enable an economically competitive and environmentally beneficial future energy system across multiple sectors.

The HydroGEN Advanced Water Splitting Materials (AWSM) Consortium was established in 2016 as part of the Energy Materials Network (EMN) under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office to enhance the performance, improve the durability, and reduce the cost of clean hydrogen production technologies, and it is helping to advance the H2@Scale vision. HydroGEN is a DOE EMN consortium that comprises several U.S. national laboratories focused on accelerating the materials research and development (R&D) of all emerging advanced water splitting pathways for clean, sustainable, and low-cost hydrogen production. The four earlystage, clean hydrogen production technologies that HydroGEN concentrates on are: low temperature electrolysis (LTE), high temperature electrolysis (HTE), photoelectrochemical (PEC), and solar thermochemical (STCH) water splitting. HydroGEN fosters cross-cutting innovation using theory-guided applied materials R&D, leverages world-class expertise and capabilities at the national labs, and encourages collaboration among industry, universities, and national labs. This article describes the basics of these advanced water splitting technologies, outlines their advantages and disadvantages, and identifies the materials R&D needs.

flexibility, operation at high current density, and long-term durability. This LTE area includes three separate technologies: (1) liquid alkaline (LA), (2) proton exchange membrane or polymer electrolyte, membrane (PEM), and (3) anion exchange membrane or alkaline electrolyte membrane (AEM) systems. LA electrolysis is the most developed of the three technologies with a long history of industrial use. It consists of two electrodes (anode and cathode) separated by a diaphragm operating in a liquid supporting electrolyte, typically concentrated potassium hydroxide (Fig. 2a). The diaphragm can be a polymer that is stable at high

Low Temperature Electrolysis (LTE) Low temperature electrolysis directly converts electrons to hydrogen through electrochemical water splitting.2 Compared to other electrolysis types, low temperature systems (< 100°C) are more mature industrially and allow for input

Fig. 1. DOE H2@Scale vision showing the flexibility of hydrogen to couple diverse domestic resources to multiple sectors and how large-scale, low-cost hydrogen can enable an affordable, reliable, clean, and secure energy system. H2@Scale supports the DOE Hydrogen Energy EarthShot goal of $1 per 1 kilogram of clean hydrogen in 1 decade.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

pH, not conductive, and such as polyethylene sulfide, polysulfone, and polyether sulfone. Advantages to the technology are primarily centered around cost, where the high pH enables platinum group metal (PGM)-free catalysts and improved durability that would not be feasible in an acidic environment. Disadvantages exist, however, and include the large footprint, low current density due to the larger physical distance between electrodes, and cost (both the cost to compress hydrogen downstream and maintenance costs associated with the caustic electrolyte). LA electrolysis has traditionally operated at constant load with larger electrode distances to minimize hydrogen crossover. LA electrolysis can be operated under variable load, and future operation will likely reduce electrode distance to minimize ohmic loss and response time while balancing crossover concerns. For proton and anion exchange membrane-based systems, the electrodes physically contact a polymeric membrane to form a membrane electrode assembly, and the zero-gap approach can improve performance by minimizing the electrode distance and ohmic loss (Fig. 2b-d). In PEM electrolysis systems, the membrane is typically Nafion™ (a perfluorosulfonic acid membrane), and the two electrodes are typically platinum (supported) at the cathode for hydrogen evolution reaction (HER, Equation 1) and iridium oxide at the anode for oxygen evolution reaction (OER, Equation 2). The catalysts are traditionally at loadings of milligrams per square centimeter. The PEM is traditionally thicker (150-250 micron) but current research has been exploring thinner members to balance ohmic loss with hydrogen crossover. Thin membranes are better for minimizing ohmic loss, while thicker membranes are better for lower crossover (resulting in higher cell efficiency) and are more durable (higher mechanical membrane stability). Development of new or improved membranes that allow for full liquid hydration operation and differential pressure, with minimal hydrogen crossover, are needed. Compared to liquid alkaline systems, PEM electrolysis has a shorter commercial history but allows for a significant increase in performance or current density, hydrogen compression at the device with back pressure, and a smaller footprint. The need for PGM catalysts and component coatings (on porous transport layers and separators between cells in a stack), however, can increase cost, and their scarcity is a concern.3 Electrocatalyst development in PEM systems has historically focused on materials discovery through admetals and ex situ oxide content. Under-explored areas in materials integration (including supports, morphology, and structure) may be useful to improve performance and lessen load requirements.4 Additionally, long-term durability

issues arise when targeting low-cost hydrogen production, through both intermittent power inputs and anticipated PGM catalyst loading reductions.5,6 Compared to other LTE technologies, AEM electrolysis systems have less commercial history and are in a developmental phase, but they share similarities with both LA and PEM electrolysis. As with PEM systems, AEM electrolyzers use a zero-gap approach, but the membrane conducts hydroxide (Fig. 2c and 2d, Equations 3 and 4), as opposed to protons. As with LA electrolysis, AEMs create a high pH environment, which enables PGM-free catalysts and component coatings.7 Operation in AEM electrolysis depends on whether the intent is to replace LA- or PEM-based systems. For a liquid alkaline replacement, supporting electrolyte (e.g., hydroxide, carbonate) is supplied to both the anode and cathode and operation is at balanced pressure (Fig. 2d). For a PEM electrolysis replacement, water is supplied to the anode and wicks through the membrane to the cathode where hydrogen evolution occurs (Figure 2c). In a water-fed AEM electrolyzer, hydrogen can be compressed through backpressure. Recent component advancements have enabled high performance, particularly in AEM electrolysis with supporting electrolytes, although maintenance of the caustic electrolyte may add to production cost.8,9,10 While efforts and progress have also accelerated water-fed AEM electrolysis systems, performance and durability have generally been lower than both the supporting electrolyte-fed AEM- and PEM-electrolysis systems, particularly when normalized to membrane thickness.11 PEM water electrolysis: (1) (2) AEM or LA water electrolysis: (3) (4)

High Temperature Electrolysis (HTE)

HTE has received extensive interest in the past 20 years as a high-efficient water splitting technology for hydrogen production, where the energy demand can be reduced because the Joule heating during HTE can be used in the water splitting processes at high temperatures.12 High temperature operation decreases electricity consumption, offset by high heat demand, which can become a cost-driver as low-cost external heat from nuclear, solar, and other sources become increasingly available. In addition, operating at high temperatures favors the reaction kinetics and enables the use of less noble (less expensive) materials such as nickel and conductive oxides, rather than platinum, as electrocatalysts.13 HTE is often referred to as solid oxide electrolysis cells and stacks (SOECs). It is also known as ceramic ion-conducting steam electrolysis system and emerges from the development of solid oxide fuel cells (SOFCs). SOEC is a reverse/ regenerative mode of SOFC, producing hydrogen instead of generating electrical power.14 There are two primary types: oxygen-ion conducting SOEC (o-SOEC) and proton conducting SOEC (p-SOEC), based on the charge carrier of the electrolyte. Figure 3 shows the working principle Fig. 2. Schematics of different low temperature electrolysis (LTE) systems. From left to right: for both SOECs. An SOEC normally consists of (a) liquid alkaline (LA) electrolysis, (b) proton exchange membrane or polymer electrolyte three layers: a hydrogen electrode (cathode), an membrane (PEM) electrolysis, (c) anion exchange membrane or alkaline electrolyte air/oxygen electrode (anode), and a solid oxide membrane (AEM) water-fed electrolysis, and (d) AEM electrolyte-fed electrolysis. Carbonfree electrons from nuclear, solar, and wind power can be coupled with these LTE systems.

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electrolyte. In o-SOEC, steam is fed into the porous cathode. When a voltage is applied, the steam is reduced at the interface of cathode and electrolyte to form hydrogen (H2) and oxygen ions (O2-), which are conducted through the dense solid electrolyte (Equation 5). The electrolyte must be dense enough to allow the oxygen ion to pass through. At the electrolyte–anode interface, the oxygen ions are oxidized to form pure oxygen gas (Equation 6). In p-SOEC, steam is fed to the anode and is oxidized to generate oxygen gas and protons (Equation 7). Protons conduct through the solid electrolyte and form pure hydrogen gas at the cathode (Equation 8). An o-SOEC is the more mature of the two technologies and typically runs between 700–850oC.15 The most common electrolytes in o-SOEC are yttria stabilized zirconia (YSZ) and scandia stabilized zirconia (ScSZ) due to their excellent ionic conductivity, high strength, good chemical stability, and compatibility with other components. Ni-cermet and (La, Sr)MnO3-δ (LSM) or (La, Sr)CoO3-δ (LSC) or (La, Sr)(Co, Fe)O3-δ (LSCF) are typical hydrogen and oxygen electrode materials, respectively.16 At the current stage, all material systems for o-SOEC and related integration have been widely studied and developed, making the o-SOEC technology poised for widespread commercialization.17 The most challenging need to be addressed is to develop more durable o-SOEC systems with remarkable cost reduction to allow cost-effective scale-up and high-throughput manufacturing processes to be exploited and implemented.18 p-SOEC is an emerging technology under HTE and operates at intermediate temperatures of 400–600oC by employing barium zirconate, barium cerate, or combined compositions as the solid electrolyte.19 Lower operating temperatures can significantly improve the cell/stack durability, minimize stack sealing problems, enable the use of less expensive materials (e.g., ferritic stainless steels for interconnect), and improve response to rapid start-up and repeat thermal cycling needs. Furthermore, p-SOEC can inherently overcome the problems that o-SOEC encounters, including the mixture of hydrogen and steam, severe delamination of electrodes at high current densities, and partial oxidation of the nickel-based electrode. While these remarkable merits exist, there are still tremendous research efforts needed to address challenges related

Fig. 3. A schematic of two types of SOECs: oxygen ion conducting SOEC (o-SOEC, left), and proton conducting SOEC (p-SOEC, right). o-SOECs typically operate at 700–850oC, while p-SOECs operate at intermediate temperatures of 400–600oC. Nuclear plants, solar, and other sources can supply the carbon-free electrical and thermal energy to these SOECs to split water and produce hydrogen.

to materials in p-SOEC (e.g., the benchmarking materials for each component) together with the integration requirement for the prototype demonstration at large scale.20,21 As the high cost of ceramics is recognized as one of several big challenges in SOEC technology, a new cell configuration—metalsupported SOEC—shows its unique advantages in that it can reduce the use of ceramics considerably while offering better mechanical strength and sealing efficiency.22 Certainly, fabrication requires further investigation to improve the cell performance and reduce the cost, ensuring that it can be leveraged by both o-SOEC and p-SOEC technologies.23 o-SOEC:

(5) (6)

p-SOEC:

(7) (8)

Photoelectrochemical (PEC) Water Splitting PEC hydrogen production is a direct conversion and one-step process which integrates light harvesting, photovoltage generation, and water splitting components into one system. The advantage of this technology is lower cost and significantly less complexity with respect to other advanced technologies for hydrogen production. The challenges center around the development of durable and efficient materials. In simple terms, PEC is similar to LTE—the main difference is that PEC generates charge carriers upon illumination and LTE uses electrons provided by an external source. In PEC hydrogen production, semiconductors and catalysts aid the formation of hydrogen through the conversion of solar energy into chemical energy. In this process, light is absorbed by semiconductor materials and in turn generates enough photovoltage to split water autonomously into hydrogen and oxygen (Equation 9). To understand the architecture of a PEC device and the need for semiconductor and catalyst materials, one should consider the energetics of the hydrogen production reaction. The thermodynamic potential to form H2 from water is about 1.23 V, which in practice becomes ~1.7 V due to the kinetics of the water splitting. These high voltages can be generated by appropriate semiconductors, which absorb light and generate and excite electron-hole pairs with an associated photovoltage that can be used for catalyzing water splitting. The magnitude of the photovoltage that a semiconductor can generate is directly related to the band gap of the material, and interfacing multiple semiconductors together (multijunction) is a route to providing an even higher photovoltage. Specifically, a multijunction is a stack of multiple light absorbing layers (e.g., Fig. 4, light absorbers 1 and 2), which ensure the generation of a sufficient photovoltage to autonomously perform the water splitting reaction. Additionally, a semiconductor’s ability to produce hydrogen (oxygen) depends on the relative position of its conduction (valence) band with respect to the reduction (oxidation) potential of water. For this reason, usually p-type semiconductors are used at the cathode side, and n-type semiconductors are used at the anode side. Upon light illumination, the band bending allows minority carriers to flow at the semiconductor’s surface and to be utilized in the water splitting reaction. Semiconductors often need to be integrated with catalysts that can lower the kinetic barriers of the water splitting reaction and enable the charge transfer to the reaction site. Specifically, HER catalysts are used at the cathode, whereas OER catalysts are used at the anode. The fabrication of optimized functional interfaces between semiconductors and catalysts ensures efficient charge transfer.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Importantly, optimal interfaces ensure PEC device performance and durability to the strongly reducing (oxidative) reaction conditions and to the extreme acidic (basic) pH used for hydrogen (oxygen) production. There are four types of PEC systems: two based on single (type-1) or dual (type-2) waterbed colloidal suspensions, and two based on multijunction photovoltaic materials that are immersed in a waterbased electrolyte (type-3, Fig. 4) and that are additionally part of a solar concentrator system and pressurized (type-4).24 Variations of these configurations, which include vapor-fed devices, are also possible and have shown promise, especially for operation under nearneutral pH conditions. Importantly, a membrane or gas separator is often used in these devices to keep H2 and O2 separated, thus ensuring the safety as well as the efficiency and enhanced collection ability of the products of interest. Figure 4 illustrates the schematic of a type-3 device with two light absorbers interfaced with the OER (anode) and HER (cathode) catalysts. The device is immersed in electrolyte. While PEC catalyst materials are usually similar to the ones used in LTE (e.g., HER: Pt, PtRu, and OER: IrO2), there are several semiconductor material candidates: silicon, metal oxides, and nitrides, as well as II-VI and III-V semiconductors.25 More recently, lead halide perovskites have also debuted as promising materials in the field, though their stability in aqueous environments still represents a major barrier.26 To date, the use of III-V multijunctions has demonstrated the most potential due to the generation of a high photovoltage. While the technological impact of the PEC approach is still in its infancy, great strides have been made in this field in the past few years. State-of-the-art PECs using III-V semiconductors show a calculated solar to hydrogen (STH) efficiency of ~19%.27 The main challenges for PEC systems are the overall efficiency, defined as the actual STH performance, and the durability of the system. Life cycle analysis has pointed to these two parameters as the major contributors to the technological impact of PEC devices.28 Thus, the development of stable and efficient semiconductor/catalyst architectures is of fundamental importance in this field. To address these issues, research has focused on the development of protective coatings. TiO2, GaN, and MoS2 are some of the coatings that have shown great promise in the field. Interestingly, recent development in theoretical approaches allow for the prediction of novel efficient yet stable compounds that can be synthesized and tested and can provide promising routes for future development.29,30 In addition, the

utilization of in situ and operando characterization techniques allows the study of corrosion mechanisms and material transformations under operating conditions.31 Specifically, the latter approach can allow rational design of protection strategies for efficient yet unstable semiconductors, which open new opportunities in the field. Providing a stable device with high STH is key to success in this field. PEC water splitting: (9)

Solar Thermochemical (STCH) Water Splitting Thermochemical cycles for producing hydrogen by splitting water are categorized thematically by the number of reactions required to complete the cycle and by the method of treatment (i.e., purely thermochemical or hybridized approaches that invoke electrochemistry to complete reaction steps within the cycle).32,33 Examples of three common cycle chemistries are illustrated in Fig. 5, and detailed chemistries for others that have been proposed or demonstrated at various scales from laboratory to small pilot can be found in seminal works dating from 2003.33,34,35,36 Akin to the breadth of the chemical processing industry, many hundreds of cycles have been considered with the notion that concentrating solar power37 or nuclear power provides carbon-free energy to drive net endothermic water splitting chemistries yielding clean hydrogen without ambiguity as to how energy is sourced. The principal advantages of thermochemical water splitting cycles are lower costs because precious metal catalysts and/or materials are not needed, and that these concepts can be industrialized to large scales, much like modern petrochemical enterprises. The two-step metal oxide cycle is conceptually the simplest. The far-left illustration in Fig. 5 shows how concentrating solarthermal energy is used to raise the temperature of a redox-active oxide (MOx) to a point where O2 will spontaneously evolve from the material; temperatures in excess of 1500°C are common. At that moment of oxygen evolution, solar energy is directly converted into chemical energy now carried by the reduced compound MOx-1. In the second part of the process, the reduced oxide is exposed to H2O at conditions where an oxygen atom is spontaneously stripped from the water molecule and put back into the oxide, leaving behind H2 and completing the cycle. There are several manifestations of twostep cycles where the oxidation state of a single element within the compound is manipulated during the process. Binaries like CeO2, SnO2, and oxides of Zn group metals have demonstrated a high degree of water splitting efficacy.38 A select group of more complex oxides comprising ternaries, quaternaries, and quinaries have also proven useful.39,40,41 When reduced, the compounds may stay solids, as in the non-volatile MOx cycles, or can change from solids to liquids or vapors depending on the temperature and desired cycle conditions. STCH water splitting:

Fig. 4. Schematic example of a PEC (type-3) device. The figure illustrates the simplified structure (left) of a PEC panel illuminated by the sun (right). The PEC device structure includes two light absorbers: an n-type semiconductor at the anode and a p-type semiconductor at the cathode for oxygen and hydrogen production, respectively. The two semiconductors should provide a photovoltage > 1.7 V to drive spontaneous water splitting and are interfaced with an OER and an HER catalysts. The device is immersed in an electrolyte and produces hydrogen and oxygen upon light illumination. A membrane or a separator can be used to aid product separation and to ensure the safety of the device. The device can be fed water (H2O) in a recirculated manner and hydrogen (H2) and oxygen (O2) are collected separately.

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(10) (11) Multistep cycles, be they purely thermochemical like the sulfuriodine example shown in Fig. 5 (center illustration) or hybrids like the sulfuric acid example shown in Fig. 5 (far-right illustration), are more complicated and involve several chemical species participating in reaction schemes that net water splitting. And as with a twostep process, the redox active elements, sulfur and iodine in these examples, remain within the cycle, requiring only water and carbon(continued on next page) 53

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free energy to be inputted. Furthermore, hybridized approaches that use electrochemistry to promote oxidation or reduction of chemical species other than water operate at voltages below 1.23 V. 31–33,42 Process complexity arises because the reaction network invariably cycles through multiple chemical species interacting in multi-phase environments housed within different chemical unit operations such as reactors and separators. The principal advantage to multi-step cycles compared to a two-step cycle is a lowering of the process temperature at the expense of added complexity. To summarize, thermochemical routes for producing hydrogen via water splitting span an extremely large concept space full of opportunities to advance the art. Interest in these cycles stems from the belief that these chemistries can be industrialized and brought to market at extremely large scale, much like the petrochemical or commodity chemical industries. To achieve this goal, advances are required in research focused on understanding the behavior of materials in extreme environments (e.g., materials subject to harsh chemical and thermal stresses), as well as finding novel methods for improving the efficiency of separations in harsh environments. Discovery of new materials and/or chemistries for thermochemical cycles (including hybrids) offers an opportunity to exploit advances in high performance computing, computational material science, ab initio theory, and fundamental science targeted at developing an atomistic understanding of redox processes.

Summary Large-scale production of low-cost, clean hydrogen societies is an important near-to-longer term strategy to decarbonize the energy systems and industry sectors. While DOE-funded efforts to bring near-term water splitting technologies like PEM electrolysis and o-SOEC to commercialization are currently underway, emerging

water splitting technologies such as AEM electrolysis, p-SOEC, PEC, and STCH are crucial to ultimately advance all pathways to clean hydrogen. Climate change is an existential issue, and it is critically important that R&D in these AWS technologies accelerate to meet the Hydrogen Energy EarthShot goal of $1 per 1 kg clean hydrogen in 1 decade, and to realize a decarbonized energy future.

Acknowledgments The authors gratefully acknowledge research support from the HydroGEN Advanced Water Splitting Materials Consortium, established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Effi ciency and Renewable Energy, Hydrogen Fuel Cell Technologies Office, under contract number DE-AC36-8GO28308 to the National Renewable Energy Laboratory (NREL), contract number DEAC07-05ID14517 to the Idaho National Laboratory, contract number DE-AC02-05CH11231 to the Lawrence Berkeley National Laboratory (LBNL), and U.S. Department of Energy’s National Nuclear Security Administration contract number DENA0003525 to Sandia National Laboratories, multi-mission laboratories managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. © The Electrochemical Society. DOI: 10.1149/2.F13214IF

Fig. 5. Schematic showing exemplar thermochemical cycles for the three classes of water-splitting redox chemistries. Far left is the simple two-step metal oxide cycle, center is the multistep cycle, and far right is the hybridized cycle that invokes an electrochemical step other than direct water electrolysis. Water and energy are the only inputs into these systems, and hydrogen and oxygen are the only outputs. All other chemical species are transformed and regenerated within the redox cycle. Nuclear plants, solar, and other sustainable power sources supply the carbon-free energy inputs to these cycles to split water and produce clean hydrogen.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

About the Authors Shaun Alia, Senior Scientist, Electrochemical Engineering and Materials Chemistry Group, National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: BS in Chemical Engineering (University of California, San Diego), MS in Chemical Engineering (University of Connecticut), PhD in Chemical Engineering (University of California, Riverside). Research Interests: Understanding electrochemical and degradation processes, component development, and materials integration and optimization. Work Experience: Research related to electrochemical energy conversion and storage, including proton and anion exchange membrane-based electrolyzers and fuel cells, direct methanol fuel cells, capacitors, and batteries. Within HydroGEN, a part of the U.S. Department of Energy’s Energy Materials Network, Dr. Alia is a low temperature electrolysis lead and has been involved through NREL capabilities in materials development and ex situ and in situ characterization. He is further active within in situ durability, diagnostics, and accelerated stress test development for H2@Scale and the H2NEW consortia. Pubs + Patents: 45+ peer-reviewed publications. https://orcid.org/0000-0002-7647-9383 Dong Ding, Senior Materials Scientist/ Engineer and Group Manager, Chemical Processing Group, Idaho National Laboratory, Idaho Falls, ID, U.S. Education: BS in Materials Chemistry and PhD in Material Science (University of Science & Technology of China). Postdoctoral fellowships (National Energy Technology Lab and Georgia Institute of Technology). Research Interests: Natural gas upgrading, High temperature water electrolysis, Advanced manufacturing, CO2 capture and conversion, Ammonia electrosynthesis, Fuel cells, and Electrocatalysis. Work Experience: Prior to joining INL, senior materials engineer at Redox Power Systems. Technical lead of HydroGEN of the Energy Materials Network, as well as H2NEW under the U.S. Department of Energy. Editorial board, Journal of Power Sources Advances; Guest editor, Frontiers in Materials, Frontiers in Chemistry, Journal of Physics: Energy, and Journal of Materials Research. Adjunct/affiliated faculty positions at University of Louisiana at Lafayette, University of South Carolina, New Mexico State University, and University of Idaho. Awards: 2021 INL-EEST Leadership award, 2020 Asian American Most Promising Engineer of the Year, 2019 Federal Laboratory Consortium Far West Award for Outstanding Technology Development. Work with ECS: Executive Committee, H-TEMP Division Pubs + Patents: 110 co-authored peer-reviewed publications (h-index: 39), 5 U.S. patents and multiple patent applications. http://orcid.org/0000-0002-6921-4504 Tony McDaniel, Principal Member, Technical Staff, Sandia National Laboratories, Livermore, CA, U.S. Education: PhD in Chemical Engineering (University of California, Los Angeles). Research Interests: A range of topical areas important to functional materials and their application to developing technologies for energy storage and

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

conversion, including complex oxides used in the production of hydrogen by thermochemical water splitting and high temperature electrochemical processes. Work Experience: Solar thermochemical technology lead for HydroGEN Advanced Water Splitting Materials Consortium. Pubs + Patents: 100+ peer reviewed papers and technical reports. Francesca Maria Toma, Staff Scientist, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. Education: MS, Pharmaceutical Chemistry; PhD in Biophysics (International School of Advanced Studies, Italy). Research Interests: Synthesis and advanced characterization of materials and catalysts for artificial photosynthesis; Renewable energy, focusing on materials synthesis, component integration, and understanding through nanoscale characterization techniques. Develops and characterizes functional (photo)electrochemical interfaces active for water oxidation, hydrogen production, and CO2 reduction. Work Experience: Marie Curie Researcher University of California, Santa Barbara (2011), Postdoctoral Scholar, University of California, Berkeley (2013). PEC technology lead in HydroGEN, Lead of the Liquid Sunlight Alliance at LBNL. Editorial board member, Progress in Materials Science. Pubs + Patents: 90+ publications, 4 patents. Awards: Alfredo di Braccio Award, Italian National Academy of Science (2016); Women in Materials Science, Royal Society of Chemistry (2018); 2021 Rising Star Award, American Chemical Society. Chair, User Executive Committee at the Molecular Foundry (2018–2019), Member Advanced Light Source User Executive Committee (2017–2019). https://orcid.org/0000-0003-2332-0798. Huyen N. Dinh, Director, HydroGEN Energy Materials Network; Manager, Electrosynthesis and Fuel Storage Science and Engineering Group, Chemistry and Nanoscience Center, and Electrons to Molecules Lead, NREL Materials, Chemicals, and Computational Science Directorate, National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: PhD in Electrochemistry (University of Calgary). Research Interests: Fuel cell catalysis (PEMFCs, DMFCs); Contaminants; Renewable hydrogen production, including photoelectrochemistry, fermentation of biomass and the photobiological approach to hydrogen production, solar thermochemical hydrogen production, renewable electrolysis, and reforming bio-oil. Work Experience: 22+ years of experience at National Laboratories and in industry. Awards: 2018 DOE Hydrogen and Fuel Cells Program R&D Award, and many NREL awards, including the 2019 Staff award and 2020 Chairman’s award. Work with ECS: Member of ECS for 31+ years, Member-atlarge, Energy Technology Division (ETD), ECS New Technology Subcommittee, ETD Srinivasan Srinivansan Young Investigator Award, ECS Diversity and Inclusion Committee, and participated in the Industry Connect Event and the Refresh and Connect Mentoring Session. Organized multiple ECS symposia and chaired multiple sessions. https://orcid.org/0000-0002-0284-8203 (continued on next page)

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References 1. https://www.energy.gov/eere/fuelcells/hydrogen-shot 2. B. Pivovar, N. Rustagi, and S. Satyapal, Electrochem. Soc. Interface, 27, 47 (2018). 3. IRENA, Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5⁰C Climate Goal, International Renewable Energy Agency, Abu Dhabi (2020). 4. S. M. Alia, Curr. Opin. Chem. Eng., 33, 100703 (2021). 5. S. M. Alia, S. Stariha, and R. L. Borup, J. Electrochem. Soc., 166, F1164 (2019). 6. K. Ayers, “High Efficiency PEM Water Electrolysis Enabled by Advanced Catalysts, Membranes and Processes,” U.S. Department of Energy (2020). 7. M. Pourbaix, Atlas of Electrochemical Equilibria in Aqueous Solutions, National Association of Corrosion Engineers, Houston (1974). 8. Y. S. Kim, “Scalable Elastomeric Membranes for Alkaline Water Electrolysis,” U.S. Department of Energy (2019). 9. P. Fortin, T. Khoza, X. Cao, S. Y. Martinsen, A. Oyarce Barnett, and S. Holdcroft, J. Power Sources, 451, 227814 (2020). 10. G. A. Lindquist, S. Z. Oener, R. Krivina, A. R. Motz, A. Keane, C. Capuano, K. E. Ayers, and S. W. Boettcher, ACS Appl. Mat. Interfaces (2021). 11. S. M. Alia, “HydroGEN: Low Temperature Electrolysis,” U.S. Department of Energy (2021). 12. A. Brisse, J. Schefold, and M. Zahid, Int. J. Hydrog. Energy, 33, 5375 (2008). 13. A. Hauch, S. D. Ebbesen, S. H. Jensen, M. Mogensen, J. Mater. Chem., 18, 2331 (2008). 14. M. A. Laguna-Bercero, J. Power Sources, 203, 4 (2012). 15. J. S. Herring, J. E. O’Brien, C. M. Stoots, G. L. Hawkes, J. J. Hartvigsen, and M. Shahnam, Int. J. Hydrog. Energy, 32, 440 (2007). 16. W. S. Wang, Y. Y. Huang, S. W. Jung, J. M. Vohs, R. J. Gorte, J. Electrochem. Soc., 153, A2066 (2006). 17. D. Ding, X. X. Li, S. Y. Lai, K. Gerdes, and M. L. Liu, Energy Environ. Sci., 7, 552 (2014). 18. P. Mocoteguy and A. Brisse, Int. J. Hydrog. Energy, 38, 15887 (2013). 19. L. Bi, S. Boulfrad, and E. Traversa, Chem. Soc. Rev., 43, 8255 (2014). 20. C. C. Duan, R. Kee, H. Y. Zhu, N. Sullivan, L. Z. Zhu, L. Z. Bian, D. Jennings, and R. O’Hayre, Nat. Energy, 4, 230 (2019).

21. H. P. Ding, W. Wu, C. Jiang, Y. Ding, W. J. Bian, B. X. Hu, P. Singh, C. J. Orme, L. C. Wang, Y. Y. Zhang, and D. Ding, Nat. Commun., 11, 11 (2020). 22. G. Schiller, A. Ansar, M. Lang, and O. Patz, J. Appl. Electrochem., 39, 293 (2009). 23. M. C. Tucker, J. Power Sources, 195, 4570 (2010). 24. B. D. James, G. N. Baum, J. Perez, and K. N. Baum, Technoeconomic Analysis of Photoelectrochemical (PEC) Hydrogen Production, Directed Technologies, Arlington (2009). 25. K. Sivula and R. van de Krol, Nat. Rev. Mater. 1, 15010 (2016). 26. S. Pan, J. Li, Z. Wen, R. Lu, Q. Zhang, H. Jin, L. Zhang, Y. Chen, and S. Wang, Adv. Energy Mater., (2021). 27. W. Cheng, M. H. Richter, M. M. May, J. Ohlmann, D. Lackner, F. Dimroth, T. Hannappel, H. A. Atwater, and H. Lewerenz, ACS Energy Lett., 3, 1795 (2018). 28. R. Sathre, C. D. Scown, W. R. Morrow, III, J. C. Stevens, I. D. Sharp, J. W. Ager, III, K. Walczak, F. A. Houle, and J. B. Greenblatt, Energy Environ. Sci., 7, 3264 (2014). 29. A. K. Singh, J. H. Montoya, J. M. Gregoire, and K. A. Persson, Nat. Commun., 10, 443 (2019). 30. Q. Yan, J. Yu, S. K. Suram, L. Zhou, A. Shinde, P. F. Newhouse, W. Chen, G. Li, K. A. Persson, J. M. Gregoire, and J. B. Neaton, Proc. Natl. Acad. Sci. U. S. A., 114, 3040 (2017). 31. G. Zeng, T. A. Pham, S. Vanka, G. Liu, C. Song, J. K. Cooper, Z. Mi, T. Ogitsu, and F. M. Toma, Nat. Mater., 20, 1130 (2021). 32. S. Abanades, P. Charvin, G. Flamant, and P. Neveu, Energy, 31, 2805 (2006). 33. D. Guban, I. K. Muritala, M. Roeb, and C. Sattler, Int. J. of Hydrog. Energ., 45, 26156 (2020). 34. L. C. Brown, G. Besenbruch, K. Schultz, S. Showalter, A. Marshall, P. Pickard, and J. Funk, High Efficiency Generation of Hydrogen Fuels Using Thermochemical Cycles and Nuclear Power, American Institute of Chemical Engineers (2002). 35. A. Steinfeld, Sol. Energy, 78, 603 (2005). 36. C. Agrafiotis, M. Roeb, and C. Sattler, Renew. Sustain. Energ. Rev., 42, 254 (2015). 37. C. A. Schoeneberger, C. A. McMillan, P. Kurup, S. Akar, R. Margolis, and E. Masanet, Energy, 206, 118083 (2020). 38. W. C. Chueh, C. Falter, M. Abbott, D. Scipio, P. Furler, S. M. Haile, and A. Steinfeld, Science, 330, 1797 (2010). 39. M. Kubicek, A. H. Bork, J. L. M. Rupp, J. of Mater. Chem. A, 5, 11983 (2017). 40. A. H. McDaniel, Curr. Opin. Green Sustain. Chem., 4, 37 (2017). 41. S. L. Millican, I. Androshchuk, J. T. Tran, R. M. Trottier, A. Bayon, Y. Al Salik, H. Idriss, C. B. Musgrave, and A. W. Weimer, Chem. Eng. J., 401, 126015 (2020). 42. F. Safari, and I. Dincer, Energy Convers. Manag., 205, 112182 (2020).

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From Hydrogen Manifesto, through Green Deal and Just Transition, to Clean Energy Act by Plamen Atanassov, Vito Di Noto, Stephen McPhail

n December 17, 2020, just before stepping out to a very different COVID-19 scarred Christmas holiday season, all European Union countries signed a short, page-anda-half document: Manifesto for the Development of a European “Hydrogen Technologies and Systems” Value Chain. The governments of kingdoms and republics as large as the Federal Republic of Germany and as small as the Grand Duchy of Luxembourg committed themselves to leading the transition to a hydrogen economy by establishing the 4th European Important Project of Common European Interest (IPCEI) framework for funding green hydrogen at a scale larger than anywhere else in the world. This agreement came just three days before the European Commission adopted a revision to its 2013 regulation on TransEuropean Networks in Energy (TEN-E), on December 20, 2020. The TEN-E regulation establishes the European Union crossborder energy infrastructure and lays out the process for selecting Projects of Common Interest (PCI). These PCIs are infrastructure projects critical to moving toward common goals of the European Union and its member states in the field of energy and play a central regulatory “push” role in promoting renewable energy. This new, revised 2021 TEN-E regulation will align closely with the ambitious climate neutrality objectives of the European Green Deal,1 which is a central piece of the European legislation following the currently implemented Recovery and Resilience Facility.2 The European Green Deal is currently being debated and refined, while the European Commission is preparing the groundwork for the third massive initiative that will shape the future of the continent in terms of wellbeing and competitiveness: the Just Transition Platform.3 What is clear is that decarbonization of society holds a central place in these three major legislative packages. The latter are practical implementation steps of the Hydrogen Strategy, the general framework for the development of a hydrogen ecosystem in Europe by 2050.4 This set of agreements makes a policy shift toward clean/renewable energy central for the European economic space and highlights the role of hydrogen technologies as a means of decarbonization of the transportation and industrial sectors. A unique attribute of these EU arrangements is the focus on hydrogen—an energy carrier that integrates electric power with energy utilization, mobility with connectivity, and manufacturing with food production and supply— as critical for European energy security and independence. The revised 2021 TEN-E regulation updates the infrastructure categories eligible for support with an emphasis on decarbonization and adds a new focus on offshore electricity grids, hydrogen infrastructure, and smart grids. It announces a new “taxonomy” for hydrogen, establishing the legal use of the terms “green hydrogen” (derived from renewable sources), “blue hydrogen” (off-setting the CO2 footprint with emission savings at least equal to those incurred during its synthesis), and “gray hydrogen” (non-zero CO2 emissions associated with its synthesis and use). Given the size of the European hydrogen market, even if measured in its almost 300 current demonstration projects, this taxonomy will have a global meaning. What is omitted is discussion of the color of nuclear electricitysynthesized hydrogen or hydrogen (potentially) derived via carbon capture technologies. Those “colors” have not yet been universally recognized (see this issue’s Chalkboard for a more in-depth look at the many proposed colors of hydrogen). The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

This summer, the European Council (EC) decided to end its support for new natural gas and oil projects and to introduce mandatory sustainability criteria for all current and future projects sponsored by the EC, and by virtue of subsequent preparation through individual states’ legislations, by the entire European Union. The EC established a transitional period until the end of 2029, during which gray hydrogen derived from natural gas can be still used. For this limited period of eight years, it is allowable to transport or store a blend of hydrogen with natural gas or biomethane. There is an envisioned set of strategic projects that will be deployed to demonstrate how, by the end of this transitional period, these hydrogen/gas blends will be replaced with clean hydrogen, dislodging natural gas from the economies of the EU member states. This policy clearly supports the standing EU policies for ending the extraction and use of coal across the member states by 2030. This drive toward green hydrogen is a hallmark of the EU hydrogen strategy. The EC aims to create a hydrogen market for Europe and hence to help the European Union to meet its commitment to achieve carbon neutrality in 2050 by proposing the development of a dedicated hydrogen grid and the creation of multiple hydrogen clusters across the EU. On the specific green hydrogen production path, the European Union aims for the scale-up of electrolyzer technology to 6 GW in 2024 and subsequently to 40 GW by 2030. This scaling up corresponds to moving from 1 million tons of green hydrogen produced from renewable sources in 4 years to a target of 10 million tons in 10 years.5 Such ambitious goals are supported by substantial dedicated funding by the member states of more than 40 billion Euro, representing the sum of the financial support provided for the different hydrogen strategies of European member states. (continued on next page)

FIG. 1. TEN-E Europe’s energy corridors. Reproduced from Ref. 5.

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The European Green Deal and the forthcoming Just Transition Platform aim to establish Europe as leading in hydrogen technology at the intersection of legislation and public acceptance, financial and industrial practices, codes and standards, workforce development, research and development, and education. In all framework documents, the EC systematically moves hydrogen into the center stage of the transition to decarbonized economy. The Fit for 55 Package is a unique and much advanced vision for an EU-wide framework for the development of a clean hydrogen economy. It is developed by Hydrogen Europe, the most established and influential group of industry and research organizations in Europe in terms of lobbying, defining, and steering the implementation of the European budget for research and innovation. Hydrogen Europe is the successor of the Fuel Cell and Hydrogen Joint Undertakings, a series of two consecutive public-private partnerships which shaped the way EU member states and their businesses develop the hydrogen economy.9 This visionary program elaborates on multiple aspects of technology transition, including road transport and maritime, under the singular vision of hydrogen and electrified mobility. It forecasts deep restructuring of energy taxation by reducing fossil fuel subsidies, eliminating double taxation, and providing fiscal rewards to those investing in clean energy technologies. This Fit for 55 Package vision is central to establishing a robust carbon reduction system capable of reaching the goal of cutting CO2 emissions by 55% in less than a decade! The research on hydrogen technologies in the EU plays a crucial role in achieving such an ambitious goal. The R&D activities are very diverse, and are funded by a broad variety of players, including the European Commission, the governments of the member states, regional bodies, and private companies. A significant number of supporting business associations and initiatives gravitate around the implementation of the hydrogen strategy in Europe, such as the European Clean Hydrogen Alliance (described above) and the European Energy Research Alliance (EERA), built as the carrier of the research agenda.10 The EERA aims to capture the holistic nature of the energy transition and constitutes 18 so-called Joint Programs

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Massively increasing the EU production capacity of green hydrogen is also one of the main objectives of the European Clean Hydrogen Alliance, a forum bringing together industry, national and local public authorities, civil society, and all other possible stakeholders to establish a comprehensive inventory of European players that are involved in the energy transition.6 The European Clean Hydrogen Alliance was launched by the European Commission simultaneously with the Hydrogen Strategy in July 2020. The scope of the activities of the European Clean Hydrogen Alliance is much broader than the production of green hydrogen, as it plans to identify and develop a pipeline of viable investment projects along the entire hydrogen value chain, extending to mobility, industry, heat, and power applications. The activities of the European Clean Hydrogen Alliance, framed in the European Union “Hydrogen Strategy,” are aiming toward the development of a clean hydrogen market for the green transition, providing a key contribution to growth and jobs. At the same time, the financial framework Next Generation EU foresees clear funding instruments to enhance a faster deployment of the transition to a hydrogen economy as a critical component of the decarbonization strategy. The ultimate target is CO2 emissions by 2030 to be reduced by 55% compared to 1990 (the reference year). To achieve this highly ambitious goal, the planned investments (covering both public and private contributions) until 2030 will be massive. Hydrogen production will attract a total 220 billion Euros, and hydrogen infrastructure and applications will receive 120 and 90 billion Euros, respectively, for a grand total of 430 billion Euros in financial volume for the onset of hydrogen economy deployment. These figures refer to the EU as a whole, and do not take into account the additional resources provided by the various member states in their individual state budgets. The latter can be significant, on the order of 5–15 billion Euros per member state covering the years until 2030. For example, Germany has planned an investment of 9 billion Euros from its internal programs.8

Ambitious scenario

Today

Business-as-usual scenario Start of commercialization

2020

Mass market acceptability1

2045 Forklifts

Taxis

Medium and large cars

City buses 4

Transportation

Trams/railways Vans Coaches Trucks

Synfuel (freight ships and aviation) Small cars

Heating and power for buildings3 Industry heat

mCHPs2 Blended hydrogen heating Pure hydrogen heating Low/medium industry heat High-grade industry heat Existing: refining4, chemicals (production of ammonia, methanol, and others), metal processing

Industry CCU (methanol, olefins, BTX)5 feedstock Steelmaking6

Power generation

Power generation, balancing, buffering

1 Defined as sales >1% within segment 2 mCHPs sales in EU independent of fuel type (NG or H2) 3 Pure and blended H2 refer to shares in total heating demand 4 Refining includes hydrocracking, hydrotreating, biorefinery 5 Market share refers to the amount of production that uses hydrogen and captured carbon to replace feedstock 6 CDA process and DRI with green H2, iron reduction in blast furnaces, and other low-carbon steelmaking processes using H2

FIG. 2. A survey of the applications of hydrogen technologies, including their expected deployment timeline. Reproduced from Ref. 7. 58

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reflecting both the technology fields and the social aspects of a clean energy transition. The Joint Programme on Fuel Cells and Hydrogen (JP FCH)11 includes many important representatives of the European research community and academia within a platform of discussion and exchange on scientific topics and R&D strategies and priorities, providing important pathways for collaboration. JP FCH aims to contribute actively to the development of tools and events that support science-based policy decisions and actions. The total portfolio of research projects on hydrogen technologies is extremely large and covers the entire value chain. As a representative example, the European Institute of Technology for Raw Materials12 has funded the project ALPE,13 which aims to minimize the loading of platinum in proton-exchange membrane fuel cells (PEMFCs). This goal is a major steppingstone toward the reduction of EU dependency on imported platinum, whose primary sources are located outside of the EU. The EU commission has also included hydrogen research as one of the topics of the Graphene Flagship, a major EU effort meant to bring closer to the market innovative products and devices enabled by graphene and graphene-related materials.14 Here the research focuses on the implementation of graphene and related materials at the electrodes of fuel cells and electrolyzers with the purpose of raising their performance and durability. The hydrogen research is also involving important companies such as ALSTOM, which developed the fuel cell hydrogen train Coradia iLint™.15 Another example is SYMBIO, a company that specializes in the development of fuel cell packages to extend the range of battery-powered vehicles; the research here led to the Pininfarina H2 Speed, a fuel cell car capable of going from 0 to 100 km/h in a record 3.4 seconds!16 In conclusion, the strong political will of the EU and its member states, coupled with important investments from both the public and the private sectors, is paving the way toward a prominent role of Europe in the full-fledged implementation of hydrogen technologies in a future that is no longer a far promise but a societal commitment.

Acknowledgments Plamen Atanassov is not funded by any EU instrument. Vito Di Noto would like to acknowledge financial s upport f rom: (a) the European Union’s Horizon 2020 research and innovation program under grant agreement 881603; (b) the project “Advanced LowPlatinum Hierarchical Electrocatalysts for Low-T Fuel Cells” funded by EIT Raw Materials. Stephen McPhail is the Coordinator of the Joint Programme on Fuel Cells and Hydrogen (JP FCH) of the European Energy Research Alliance – EERA. © The Electrochemical Society. DOI: 10.1149/2.F14214IF

About the Authors Plamen Atanassov, Professor, Departments of Chemical & Biomolecular Engineering, Materials Science & Engineering and Chemistry, National Fuel Cell Research Center, University of California, Irvine, CA, U.S. Education: PhD in Chemistry/Electrochemistry (Bulgarian Academy of Sciences, Sofia, Bulgaria) Research Interests: Electrocatalysts for fuel cells: Non-platinum electrocatalysts and nano-structured catalysts for PEMFC and AMFC; Biological fuel cells based on enzymecatalyzed electron transfer and microbial fuel cells; Functional nanomaterials, rational materials design and biomimetic/bioinspired approaches in materials design. Pubs + Patents: 430+ publications in peer-reviewed journals, 20+ book chapters and one edited book, 57 issued US Patents, h-index 88, 31,000+ citations. Awards: Fellow of the National Academy of Inventors (2017), Vice President of the International Society of Electrochemistry (2015–2017), Fellow of the International Society of Electrochemistry (2020). The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Work with ECS: Fellow of The Electrochemical Society (2107), ECS Energy Technology Division Research Award (2018), Memberat-Large, Physical & Analytical Electrochemistry Division and Energy Technology Division, Multiple symposia and workshops, Finance committee service, Member 20+ years Websites: https://engineering.uci.edu/users/plamen-atanassov https://scholar.google.com/ citations?user=CPilx4wAAAAJ&hl=en&oi=ao https://orcid.org/0000-0003-2996-472X Vito Di Noto, Professor of Electrochemistry for Energy and SolidState Chemistry, Department of Industrial Engineering, University of Padova, Italy Education: PhD in Chemistry (University of Padova, Italy). Research Interests: Electrode materials and electrolytes for energy conversion and storage devices: anion-exchange membrane fuel cells (AEMFCs), proton exchange membrane fuel cells (PEMFCs), high-temperature proton exchange membrane fuel cells (HTPEMFCs), direct methanol fuel cells (DMFCs), PEM electrolyzers and redox flow batteries (RFBs). Polymer electrolytes and electrode materials for secondary batteries based on alkaline and alkalineearth elements (e.g., Li, Mg, Na, Ca). Study of the electric response of ion-conducting, electric and dielectric materials by Broadband Electrical Spectroscopy (BES). Work Experience: 30+ years of experience in R&D of advanced functional materials for electrochemical energy conversion and storage devices, including primary and secondary batteries running on alkaline and alkaline-earth elements. In the late 1990s, pioneered the secondary magnesium ion battery and devised breakthrough approaches for the synthesis of electrolytes and electrode materials. He also provided seminal contributions to the understanding of the mechanisms of ion conduction in condensed phases. Pubs + Patents: 312 published papers (263 peer-reviewed papers, 10 book chapters), 30 patents (13 international and 17 national, 13 were sold) and 10 papers in proceedings. 296 meeting contributions. h-index: 49 Google Scholar, 45 (SCOPUS + ISI). 7780+ citation. Awards: Special Prize “Alessandro Volta” (2000); Japan Society for the Promotion of Science Fellow (since 2002); Premio “Amministrazione, Cittadini, Imprese” (Prize “Public Administration, Citizens, Enterprises”) (2018); President of the Italian Electrochemical Society (since 2020). Work with ECS: Member since 2003; ECS Fellow (2019); Past Member, Executive Committee of the Energy Technology Division (ETD); Currently Member-at-Large, Executive Committee, Energy Technology Division and Physical and Analytical Electrochemistry Division. Organizor/co-organizer of 35+ thematic sessions of ECS; Member and later President of the committee for the assignment of the ETD Srinivasan Award (2014–2017; 2021); Member, ETD Graduate Student Award committee (2014–2017; 2021). Websites: https://www.dii.unipd.it/category/ruoli/personale-docente ?key=1D56F2193C0F237DDD04C70DF3C19F02 http://wwwdisc.chimica.unipd.it/lab_DiNoto/ https://orcid.org/0000-0002-8030-6979 Stephen J. McPhail, Coordinator of the Joint Programme on Fuel Cells and Hydrogen, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Education: MSc in Mechanical Engineering, PhD in Thermal Fluid Dynamics Research Interests: High-temperature fuel cells and electrolyzers, Cell and system characterization. (continued on next page) 59

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Work Experience: Researcher at ENEA since 2007. He is coordinator of the EERA (European Energy Research Alliance) Joint Programme on Fuel Cells and Hydrogen and the Italian member of the Technical Collaboration Programme (TCP) on Advanced Fuel Cells of IEA. He has coordinated 4 EU funded projects (FP7 and H2020) and participated in a further 9 EU funded projects. He is member of several international committees on fuel cells and hydrogen (IEC, mission innovation, etc.). Papers + Patents: Coauthor of 58 papers on the topic, h-index 17. Awards: Winner of 2 IEC “1908” Awards. Websites: www.enea.it, www.eera-fch.eu https://orcid.org/0000-0003-3045-0945

References 1. https://ec.europa.eu/info/strategy/priorities-2019-2024/ european-green-deal_en 2. https://ec.europa.eu/info/business-economy-euro/recoverycoronavirus/recovery-and-resilience-facility_en 3. https://ec.europa.eu/info/strategy/priorities-2019-2024/ european-green-deal/finance-and-green-deal/just-transitionmechanism/just-transition-platform_en)

4. https://ec.europa.eu/energy/sites/ener/files/hydrogen_strategy. pdf 5. https://www.consilium.europa.eu/en/infographics/ten-e-energyinfrastructure/ 6. https://www.ech2a.eu/ 7. https://www.fch.europa.eu/sites/default/files/Hydrogen%20 Roadmap%20Europe_Report.pdf 8. h t t p s : / / w w w. b m w i . d e / R e d a k t i o n / E N / P u b l i k a t i o n e n / E n e r g i e / t h e - n a t i o n a l - h y d r o g e n - s t r a t e g y. p d f ? _ _ blob=publicationFile&v=6 9. https://www.hydrogeneurope.eu/wp-content/uploads/2021/06/ Hydrogen-Europe-Position-Paper-on-the-Fit-for-55-Package. pdf) 10. https://www.eera-set.eu/ 11. www.eera-fch.eu 12. https://eitrawmaterials.eu/ 13. https://www.alpe-kic.eu/ 14. https://graphene-flagship.eu/research/work-packages/workpackage-11-energy-generation/ 15. https://www.alstom.com/solutions/rolling-stock/coradiailinttm-worlds-1st-hydrogen-powered-train 16. https://www.symbio.one/en/pininfarina-h2-speed-etgreengt-h2-2/

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Hydrogen: Targeting $1/kg in 1 Decade by Bryan S. Pivovar, Mark F. Ruth, Deborah J. Myers, Huyen N. Dinh

he societal energy system is evolving rapidly as the impacts of our existing energy system are better appreciated and advances in wind and solar energy technologies have dramatically decreased the cost of renewable resources. Simultaneously, the importance of energy transfer across timeframes (e.g., dispatchable generation, long-duration storage) and the difficulty of decarbonizing the industrial loads and transportation demands using electricity are being recognized. These changes result in a much greater need and role for hydrogen and electrochemical technologies. This need has resulted in a major focus across the globe on developing and implementing different hydrogen-relevant technologies to meet cost targets that enable large-scale commercial viability and deployment. At the center of this need is achieving lowcost clean hydrogen in the near future.

The U.S. Department of Energy Hydrogen Energy EarthShot Along these lines, the U.S. Department of Energy recently launched the Hydrogen Energy EarthShot (“Hydrogen Shot”) which seeks to reduce the cost of clean hydrogen to $1 per 1 kilogram in one decade (Fig. 1).1 Achieving the Hydrogen Shot goal would enable the rapid and widespread deployment of clean hydrogen as a critical component of a clean, sustainable global energy system. Reaching the $1/kg goal is highly dependent on several factors, including the evolution of the electrical energy system to increase renewable energy deployment and low electricity costs; advances in electrolysis technology and manufacturing readiness; and infrastructure build-out and hydrogen market establishment that results in the ability to make, move, store, and use clean hydrogen economically while spurring job creation.

Potential Hydrogen Markets

Fig. 1. Hydrogen Energy EarthShot target: $1/kg for clean hydrogen in one decade. From Ref. 1.

heat pumps are being developed to provide space and water heating for residential and commercial buildings and are likely to be installed in place of natural gas furnaces and water heaters in the next few decades. Battery electric vehicles are becoming prevalent and are ideal for short-distance road transportation where range, charging time, and charging access are not major concerns. As the price of batteries drops, short-duration electricity storage is likely to increase, thus enabling an increased penetration of variable renewable generation. However, eliminating emissions from several sectors will be difficult. These sectors include long-distance transportation such as aviation, shipping, and heavy-duty trucking; industries where iron and steel and cement are large carbon emission sources; and loadfollowing electricity, which provides reliable electricity when the load exceeds generation and batteries are discharged (e.g., a series of hot, hazy days). As shown in Fig. 2, those sectors are the source of over 25% of global carbon emissions. Hydrogen has the potential to be a key component in decarbonizing those difficult-to-abate sectors. If hydrogen is used for those applications, its market size will potentially grow by up to an order

Hydrogen, a carbon-free energy carrier, has long been (continued on next page) considered to be the cornerstone of a fully decarbonized energy system. However, its viability in this role in a sustainable energy system has been limited for two reasons: (1) lack of consideration of the environmental impacts of other energy alternatives, and (2) the cost to produce hydrogen from renewables. The situation is changing due to the recognition that many of the simpler decarbonization solutions are insufficient to meet the climate goal of a reduction of ≥80% greenhouse gas emissions and that electricity markets are changing due to the proliferation of renewable electricity generation. This increase in renewable market penetration enables the production of inexpensive, clean hydrogen. Society’s perspective on the need to decarbonize our energy use is changing rapidly. Electrification is the primary option for decarbonizing many applications because the price of green electricity is dropping and technologies that utilize electricity Fig. 2. Industry, long-distance transport, and load-following electricity generation are the source of over 25% of global anthropogenic carbon emissions and are difficult to decarbonize. From Ref. 2. Reprinted with permission are developing quickly. For example, from AAAS. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

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of magnitude.3 Heavy-duty, over-the-road transport requires long distances between fueling stops and for those stops to be short in duration. Because storage volume is less of a factor than for light-duty vehicles, the heavy-duty trucks have space for hydrogen storage and, if they are converted to fuel cell electric drivetrains, they can meet those requirements.4 Aviation and marine shipping require carbonemission-neutral, higher-energy-density fuels such as biofuels, synthetic hydrocarbons, or ammonia. Clean hydrogen (produced via water electrolysis of renewable energy) has the potential to be a key component of all three of those options because processes using it can increase the energy yield per acre of biofuels, synthetic hydrocarbons are likely to be produced using hydrogen and carbon dioxide, and ammonia is produced using hydrogen and nitrogen. The iron and steel sector’s primary carbon emissions are due to the use of metallurgical coal to reduce iron ore to pure iron and to provide heat for the process. Technologies are being developed for the direct reduction of iron using hydrogen rather than metallurgical coke. The most economical solutions for decarbonizing load-following electricity are likely to utilize low-cost chemical energy storage peaking electricity generators that operate a fraction of the year (<20%). In many locations, hydrogen can be produced when variable renewable electricity generation exceeds the load, can be stored geologically at low cost, and then can be used by either fuel cells or combustion turbines to meet the load when needed. In locations where geology does not allow for hydrogen storage, alternatives such as liquid fuels or ammonia are additional options. Those fuels are likely to be the same ones used for aviation or marine shipping; thus, clean hydrogen would be used to produce them. As for all of these examples, hydrogen’s greatest opportunities are in sectors that otherwise would be very difficult to decarbonize and often have the greatest impact on local criteria pollutants in urban areas. The opportunities for using hydrogen in those difficult-to-abate sectors are also growing because the cost of clean hydrogen is falling. One key economic factor for clean hydrogen is the price of electricity, which is dropping and becoming more volatile due to increases in renewable wind and solar generation. Electrolysis can benefit from these lower prices because it can be operated as a controllable load—operating when electricity prices are low and turned off or down when electricity prices are high. Operating under a strategy where electricity is used only during the lowest-cost hours results in a tradeoff between the cost of electricity and the amount of hydrogen produced to achieve a return on the initial investment—lower capacity factors (operating fewer hours annually) facilitate the use of lower-

Fig 3. HLC versus operating time for controllable electrolyzers with several purchase costs. A lower electrolyzer cost can achieve a lower minimum HLC and provide more flexibility to the grid by operating fewer hours annually. From Ref. 5. 62

cost electricity, but annual hydrogen production is reduced. Thus, the required return per unit hydrogen basis needs to be larger on a per unit basis than for systems operating at higher capacity factors. The return per unit of hydrogen can also be increased by reducing the capital investment (i.e., lower cost of electrolyzers).

Opportunities for Low-Cost Hydrogen The electrolyzer’s capital cost is a key economic factor in determining the hydrogen levelized cost (HLC). Figure 3 shows an analysis of the impact of electrolyzer capital costs on hydrogen levelized costs using electricity rates for the Palo Verde region of the United States in 2017. This figure shows that the optimal operation for electrolyzers with higher capital costs is at higher capacity factors— thus at a higher electricity price. Reducing the capital cost from a value close to today’s prices ($900/kW electrolyzer purchase cost) to $100/kW would reduce the minimum hydrogen levelized cost by 50% and allow operation over a wider range of capacity factors and thus remains a key focus of achieving HLC targets. Figure 3 highlights the ability to achieve significant cost reductions in HLC using electricity rate structures that have already existed in wholesale markets in the United States by implementing specific operating strategies and through decreasing the capital costs of hydrogen electrolysis. Figure 4 presents a “waterfall” chart that highlights a potential pathway to achieving the Hydrogen Shot HLC target of $1/kg and an interim (mid-term) target of $2/kg.6 The largest cost savings factor in achieving these reductions is a drop in the capital costs (and associated operating and maintenance [O&M] costs) of electrolyzers, while increasing electrolysis efficiency and electrolyzer lifespans will result in less significant, but still substantial, cost improvements. Finally, the ability to operate intermittently on lower-cost electricity also results in significant cost savings. Taken together, these cost savings would result in a pathway to achieving the Hydrogen Shot target of $1/kg hydrogen. A critical caveat to these cost savings assumptions is that they need to be achieved without negatively impacting durability. Significant research and development efforts are required to pursue the advances targeted in Fig. 4. There are three types of commercial water electrolyzers and one type of electrolyzer in the developmental stage: proton-exchange or polymer electrolyte membrane (PEM), liquid alkaline (LA), solid oxide (SOEC), and anion-exchange membrane or alkaline electrolyte membrane (AEM), respectively.7 Each of these technologies has advantages and challenges associated with its optimal operating temperature, its materials of construction, and, specifically, the influence of operating conditions on components and material

Fig. 4. The HLC can meet the Hydrogen Shot target by increasing efficiency, reducing capital cost, and integrating with variably priced electricity as long as degradation does not increase. Fixed O&M costs are costs incurred whether the electrolyzer is operating or not and include labor, maintenance, property expenses, and others. From Ref. 5. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Research and Development Needs PEM Electrolysis

Fig. 5. PEM electrolysis stack capital cost reduction to meet the H2NEW ultimate target of $100/kW requires both R&D (to improve performance and lower catalyst loading) and a growth in manufacturing. From Ref. 5.

degradation. While the analyses summarized in Figs. 3 and 4 are not specific to PEM electrolyzers, they relied on operating strategies and costs most in line with PEM electrolysis systems, such as the ability to operate intermittently due to the lower-temperature operation and robustness of the cell and stack materials. The PEM electrolysis cell unit is based on a perfluorosulfonic acid membrane coated with an unsupported iridium oxide anode (oxygen evolution) catalyst, a carbon-supported platinum nanoparticle cathode (hydrogen evolution) catalyst with a titanium mesh anode flow field and a platinum-coated titanium anode porous transport layer (PTL), and a carbon-based cathode porous gas diffusion layer (GDL) and flow field.7 Due to the highly oxidizing conditions on the PEM electrolyzer anode, a suitable electron-conducting support for the iridium oxide anode catalyst, similar to the carbon support for the platinum cathode catalyst, has not yet been identified. Therefore, the iridium oxide particles are relatively sizeable, and a large fraction of the iridium oxide is buried in the interior of these particles and not participating in the oxygen evolution reaction (OER). PEM electrolyzer anodes also lack a corrosion resistant layer with fine porosity, akin to a microporous layer in PEM fuel cells, and a high spatial density of electrical connection points to the anode catalyst layer. PEM electrolysis cells thus contain higher anode catalyst loadings than are needed to sustain the desired current densities to enable adequate electronic conductivity and connectivity throughout the anode. Iridium oxide catalysts also degrade, especially with intermittent operation, and higher loadings are currently needed to achieve the desired lifetimes.8 As capital costs are so critical to the HLC, an analysis was performed regarding PEM electrolyzer stack capital costs and target areas for capital cost savings. The “waterfall” chart in Fig. 5 summarizes the results of this analysis, showing a potential pathway to reducing PEM stack capital costs from a projected current cost of $350/kW to a midterm target of $200/kW to a H2NEW ultimate target of $100/ kW. Significant decreases in the cost of all components, including the catalyst coated membrane, bipolar plate, cathode GDL, anode GDL, frame, and assembly, are expected based on the current costs and potential for improvements in both materials and manufacturing methods. These cost savings are the result of increasing operating current density, decreasing platinum group metal (PGM: Ir and Pt) loadings, and savings associated with scaling up production. Scale benefits cost competitiveness for two reasons. First, scale allows each site to use their manufacturing equipment optimally instead of having some equipment sit idle while waiting for others to complete runs. It also increases the efficiency of the supply chain, thus increasing competition and reducing the price of components.

For PEM electrolysis, to increase the current density and decrease catalyst loading without negatively impacting durability, stable and durable materials need to be developed. The development areas include: (1) OER catalysts with higher electrocatalytic activity per mass of PGM; (2) electronically conductive, high-surface-area, corrosion-resistant catalyst supports; (3) corrosion-resistant oxygen electrode PTLs and microporous layers (PTLs/MPLs) with decreased reliance on PGM coatings, while maintaining low contact resistance with the oxygen electrode and desirable water and oxygen transport properties; (4) membranes with low hydrogen permeabilities that also are less susceptible to swelling in water than the standard perfluorosulfonic acid membranes, such as Nafion; and (5) membrane reinforcements to enable differential pressure operation. In the case of OER electrocatalysts, PTLs, and coatings, challenges lie in finding materials that both provide the desired functional properties and are oxidatively stable at the high potentials and acidic environment of the oxygen electrode (anode). At a fundamental level, degradation mechanisms for the anode catalyst, the ionomer, the membrane, and PTL coatings need to be characterized and understood at the nanoscale to develop improved materials and to effectively develop accelerated tests for predicting long-term performance and to predict lifetimes.8,9 In addition, the formation of effective electrode structures and interfaces between electrode and cell components requires a fundamental understanding of the interactions of materials during fabrication (e.g., in the catalyst-ionomer inks) and how these interactions affect, for example, the rheology behavior of the inks, the uniformity of the electrode layer thickness, and the structure, function, and durability of the cell layers. The techno-economic analyses described above are specific to PEM electrolysis. However, there are other electrolysis technologies that are promising and that will require more effort and time to achieve the Hydrogen Shot goals. The R&D needs for these alternate water splitting pathways are described below.

Alkaline Electrolysis

LA electrolysis is the most mature technology, but there are still opportunities for technological advancement, which could keep it competitive in future years. Technological advances for LA include operation at higher current density with high efficiency, and thinner and stronger diaphragms to enable a compact system that can operate under variable load and pressure, with minimal reactant and product crossover and faster response time. AEM electrolysis and SOEC, described in the next section, are two developmental water splitting technologies that are being studied by the HydroGEN Energy Materials Network and H2NEW consortia. Parallel efforts in these alternate technologies can help accelerate electrolysis technology. Like PEM, and unlike alkaline (LA) electrolysis, AEM electrolysis has a relatively fast response time and can adapt to transient renewable power loads from solar and wind energy. AEM and PEM electrolysis can also operate at high pressure, which is desirable to enable volumetrically efficient storage of hydrogen and to minimize the need for downstream compression and transport. AEM electrolysis has the potential to reduce cost greatly because it uses PGM-free catalysts. The primary challenge for AEM electrolysis development is finding and mitigating degradation mechanisms to achieve competitive durability. The fundamental issues lie in the areas of understanding and mitigating the anode electrocatalyst degradation, particularly when operating on pure water; degradation of the anion-exchange ionomer in the electrode layers, particularly at the ionomer-electrocatalyst interface, and poisoning of the electrocatalysts by these degradation products; and membrane degradation at elevated temperatures. Further membrane development is needed, as chemically and thermally stable, mechanically durable, hydrogen impermeable, and thin AEMs with high anion conductivity still do not exist for high (continued on next page)

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current density operation. The HydroGEN consortium is addressing these and other R&D needs, such as tolerance to contaminated water and improving interfacial transport and durability.

SOEC

SOECs operate at higher temperatures than PEM and AEM electrolysis, typically 700‒850°C for an oxygen-ion conducting SOEC (o-SOEC) and 400‒600°C for a proton conducting SOEC (p-SOEC). These high-temperature electrolysis technologies can split water at higher efficiency than low-temperature electrolysis systems by using both electrical and thermal energy, and at potentially lower cost if inexpensive heat is used. The main issues impeding widespread implementation of SOECs are gradual degradation of cell performance during steady-state operation and degradation or fracturing of the cell components, with catastrophic failure with temperature cycling. The processes that contribute to stack performance degradation, specifically changes to the bulk, surface, and interfaces between cell layers and between the stacks and balance of plant components, are in need of further investigation to enable degradation mitigation through materials development.10 These processes include corrosion of the metallic bipolar plates, alteration of the oxide defect chemistry, and formation of contaminants in the gas atmospheres from stack component degradation that can deposit on and deactivate the electrodes. The redox processes behind these degradation mechanisms and the role of hydrogen in surface and bulk structural degradation are also in need of further investigation. Prevalent SOEC contaminants include gas-phase silica species arising from the sealant materials, which are transported to and deposited on the electrode surface, leading to electrode deactivation. The H2NEW and HydroGEN consortia are addressing the materials R&D needs for o-SOECs. Additionally, the HydroGEN consortium is addressing the R&D needs of the emerging p-SOEC. Specifically, HydroGEN is working on understanding the proton conduction mechanism to accelerate the development of more conductive electrolyte materials, which should result in higher cell performance with higher Faradaic efficiency at reduced temperatures, leading to more efficient hydrogen production and lower hydrogen cost.

Summary Clean hydrogen, enabled by low-cost renewables and nextgeneration electrolyzers, offers a pathway to low-cost hydrogen and the ability to meet the Hydrogen Energy EarthShot target of $1/kg by 2030. Reaching this target depends on several critical factors, including access to growing quantities of low-cost electricity; advances in electrolysis technology and manufacturing; and the evolution of hydrogen infrastructure and commercial markets. These advances all must be achieved in parallel to meet the demands and constraints of our evolving energy system. The coming decade will be critical to maximizing hydrogen’s role in transitioning to a sustainable global energy system.

Acknowledgments This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC3608GO28308, and in part by UChicago Argonne, LLC, Operator of Argonne National Laboratory, a U.S. Department of Energy Office of Science laboratory, operated under Contract No. DEAC0206CH11357. The authors gratefully acknowledge funding support from the H2NEW Consortium and HydroGEN Advanced Water Splitting Materials Consortium, established by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen Fuel Cell Technologies Office The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. 64

Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. © The Electrochemical Society. DOI: 10.1149/2.F15214IF

About the Authors Bryan Pivovar, Senior Research Fellow and Electrochemical Engineering and Materials Chemistry Group Manager, Chemistry and Nanosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: PhD in chemical engineering (University of Minnesota). Research Interests: Fuel cells and electrolysis. Work Experience: Led fuel cell R&D at Los Alamos National Laboratory prior to joining NREL, where oversees NREL’s electrolysis and fuel cell and materials R&D. Recently named Director, U.S. Department of Energy consortium H2NEW (Hydrogen from Next-generation Electrolyzers of Water). Pubs + Patents: 150+ papers with 10,000+ citations. Awards: Tobias Young Investigator Award (2012) and Energy Technology Division Research Award (2021) from The Electrochemical Society. Work with ECS: Led efforts and organized workshops in subfreezing effects, alkaline membrane fuel cells (2006, 2011, 2016, and 2019), and renewable hydrogen at the gigaton scale (2019). https://orcid.org/0000-0001-5181-5363 Mark Ruth, Manager of the Industrial Systems and Fuels Group in the Strategic Energy Analysis Center at the National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: BS in Chemical Engineering (University of Colorado). Research Interests: Improving energy use in the industrial and transportation sectors, Developing methods to value opportunities in the energy sector, Technical analyses of hydrogen and bioenergy systems. Work Experience: 28 years at NREL; Leads the multi-laboratory effort to analyze the technical and economic potential of the H2@ Scale concept and analyses of the economic potential to convert existing nuclear power plants to flex between electricity and hydrogen production Website: www.nrel.gov/analysis https://orcid.org/0000-0002-1838-0617 Deborah Myers, Senior Chemist and Leader of the Hydrogen and Fuel Cell Materials Group, Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, U.S. Education: PhD in Chemistry (University of Illinois Urbana-Champaign). Research Interests: Electrocatalysis and surface electrochemistry; Materials development, characterization, electrode design, and optimization, performance durability of electrochemical devices, such proton exchange and alkaline exchange membrane fuel cells and electrolyzers; in situ and operando x-ray spectroscopy, scattering, and tomography characterization of these devices and materials. Work Experience: 32 years at ANL, Co-lead of the U.S. Department of Energy multi-national laboratory consortium “ElectroCat 2.0,” Deputy Director of H2NEW (Hydrogen from Next-generation Electrolyzers of Water), Deputy Director for Materials Development in the M2FCT (Million Mile Fuel Cell Truck) consortium. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Papers + Patents: 92+ publications, 8 patents, 2 book chapters. Awards: DOE Hydrogen and Fuel Cell R&D Awards (2020, 2004, 2000), U.S. Car Award for the Fuel Cell Technology Team (2011). Work with ECS: Member since 1988. Co-edited 2 focus issues of the Journal of the Electrochemical Society and 1 volume of ECS Transactions. Website: https://www.anl.gov/profile/deborah-j-myers https://orcid.org/0000-0001-9299-3916

References

Huyen N. Dinh, Director, HydroGEN Energy Materials Network; Manager, Electrosynthesis and Fuel Storage Science and Engineering Group, Chemistry and Nanoscience Center, and Electrons to Molecules Lead, NREL Materials, Chemicals, and Computational Science Directorate, National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: PhD in Electrochemistry (University of Calgary). Research Interests: Fuel cell catalysis (PEMFCs, DMFCs); Contaminants; Renewable hydrogen production, including photoelectrochemistry, fermentation of biomass and the photobiological approach to hydrogen production, solar thermochemical hydrogen production, renewable electrolysis, and reforming bio-oil. Work Experience: 22+ years of experience at National Laboratories and in industry. Awards: 2018 DOE Hydrogen and Fuel Cells Program R&D Award, and many NREL awards, including the 2019 Staff award and 2020 Chairman’s award. Work with ECS: Member of ECS for 31+ years, Member-atlarge, Energy Technology Division (ETD), ECS New Technology Subcommittee, ETD Srinivasan Srinivansan Young Investigator Award, ECS Diversity and Inclusion Committee, and participated in the Industry Connect Event and the Refresh and Connect Mentoring Session. Organized multiple ECS symposia and chaired multiple sessions. https://orcid.org/0000-0002-0284-8203

1. “Hydrogen Shot,” U.S. Department of Energy, Accessed September 20, 2021. 2. S. J. Davis, N. S. Lewis, M. Shaner, S. Aggarwal, D. Arent, I. L. Azevedo, S. M. Benson, T. Bradley, J. Brouwer, Y.-M. Chiang, C. T. M. Clack, A. Cohen, S. Doig, J. Edmonds, P. Fennell, C. B. Field, B. Hannegan, B.-M. Hodge, M. I. Hoffert, E. Ingersoll, et al., Science, 360, eaas9793 (2018). 3. M. Ruth, P. Jadun, N. Gilroy, E. Connelly, R. Boardman, A. J. Simon, A. Elgowainy, and J. Zuboy, The Technical and Economic Potential of the H2@Scale Concept within the United States, National Renewable Energy Laboratory, Golden, CO (2020). 4. D. A. Cullen, K. C. Neyerlin, R. K. Ahluwalia, R. Mukundan, K. L. More, R. L. Borup , A. Z. Weber , D. J. Myers, and A. Kusoglu, Nature Energy, 6, 462 (2021). 5. A. Badgett, M. Ruth, and B. Pivovar, in Electrochemical Power Sources: Fundamentals, Systems, and Applications: Hydrogen Production by Water Electrolysis – Fundamentals and Applications, T. Smolinka and J. Garche, Editors, Chapter 10, Elsevier (2021). 6. B. Pivovar and R. Boardman, “H2NEW: Hydrogen (H2) from Next-generation Electrolyzers of Water Overview,” DOE Hydrogen Program 2021 Annual Merit Review and Peer Evaluation Meeting (2021). 7. S. A. Grigoriev, V. N. Fateev, D. G. Bessarabov, and P. Millet, Int. J. Hydrogen Energy, 45, 26036 (2020). 8. S. M. Alia, S. Stariha, and R. Borup, J. Electrochem. Soc., 166, F1164 (2019). 9. K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar, and M. Bornstein, Ann. Rev. Chem. Biomol., 10, 219 (2019). 10. B. Pivovar, N. Rustagi, and S. Satyapal, Electrochem. Soc. Interface 27, 47 (2018). 11. M. Reisert, A. Aphale, and P. Singh, Materials, 11, 16 (2018).

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

PEM Electrolysis, a Forerunner for Clean Hydrogen by Kathy Ayers, Nemanja Danilovic, Kevin Harrison, Hui Xu

roton exchange membrane (PEM) electrolysis was originally developed in the 1950s and 1960s by General Electric for space applications to generate oxygen for astronaut life support. The technology was then applied in submarines, starting with companies like Hamilton Sundstrand (now Collins Aerospace). Since then, several companies have transitioned the same basic technology to products for hydrogen generation at various scales. Figure 1 shows the core components of a PEM electrolyzer cell. Starting from the center of the device, the key enabler is the ion conducting membrane, which allows the cell to safely operate at differential pressure, and without supporting liquid electrolyte. The membrane contributes a large portion of the cell overpotential, especially at lower operating temperatures (e.g., <60°C) and higher current densities (e.g., >2 A/cm2).1 The membrane overpotential can be 400 mV or higher under these conditions. This result is largely due to electrolyzer membranes still being several times thicker than PEM fuel cell membranes. The membrane contacts the anode and cathode catalyst layers, which consist of highly active platinum-group metal nanoparticles. While the oxygen evolution overpotential is similar in scale to the membrane overpotential, it is relatively constant with current density, and the high electrochemically active surface area of both electrodes enables the cells to operate at higher current densities than traditional alkaline electrolyzers.2 In theory, the catalyst can be applied to either the membrane or the porous transport layer/gas diffusion layer, and cells have been tested in both configurations with similar performance. The porous transport layer (PTL) at the anode and the gas diffusion layer (GDL) at the cathode also directly contact the catalyst layers and provide both electrical contact to the catalyst as well as fluid transport to and from the electrode surface. The PTL is porous metal, while the GDL is porous carbon. The PTL typically has to manage much higher liquid water flow, because water is a reactant on the anode side, while the cathode typically has much smaller amounts of liquid water, dragged across the membrane with the protons generated at the anode. The PTL also must manage oxygen bubble removal from the electrode surface. Finally, the bipolar plate separates each cell from the next, and also has flow geometry designed to assist in water flow through the stack. The bipolar plate must balance several material requirements: resisting hydrogen embrittlement on the hydrogen side of the cell, maintaining mechanical integrity between cells, and providing conductivity on the anode side of the cell while resisting oxidation in the high voltage, low pH environment.3 A key advantage of PEM electrolyzers is the ability to operate at differential pressure. This functionality is possible because the membrane prevents bubble crossover, unlike porous separators that require the two electrode compartments to be carefully balanced in pressure (within inches of water) to avoid gas mixing. This difference in pressure allows the cell stack to be used to electrochemically compress the hydrogen at low additional energy versus pure water splitting. Even moderate compression of the hydrogen to a few bar

Fig. 1. Core components of a PEM electrolyzer cell. GDL = gas diffusion layer; PTL = porous transport layer. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

can help with mechanical compression by increasing the feed pressure to the compressor, allowing higher gas throughput than hydrogen at ambient pressure. Therefore, the hydrogen compartment can be pressurized, while the oxygen compartment remains at ambient pressure. Pressurized oxygen is extremely hazardous, particularly above about 10 bar, because everything can become a fuel in oxidant concentrations that high. All that is needed is an ignition source like a static charge to burn even materials like titanium. To safely design high-pressure systems with balanced hydrogen and oxygen pressures, stringent cleanliness requirements need to be met, including particle counting.4 Because the oxygen is not usually captured in these systems anyway, pressurizing the oxygen does not have any real benefit, and would add significant cost to the stack. Similarly, the water-oxygen loop in the balance of the plant can remain at ambient pressure, simplifying the balance of plant design and reducing cost due to the ability to leverage vessels with thinner walls. These systems are highly scalable, leveraging repeating units of the construction above. They also have attractive operating characteristics for energy applications. Electrolyzers in general have the advantage of separating the power capability (size of the electrolyzer stack) from the storage capacity (size of the hydrogen tanks), unlike in traditional batteries where both parameters have to be achieved by the same device.5 This characteristic gives electrolysis an advantage for long-duration energy storage, since increased storage just means more or larger hydrogen tanks. However, the cost and efficiency of these devices still need to be improved at scale in order to displace other sources of hydrogen on a cost basis.

Working Characteristics In addition to the advantage of decoupling the electrode scale and the storage scale, electrolysis has a large dynamic range as well as fast response times that are conducive to integration with renewable energy sources such as wind and solar. Figure 2, left, shows the increased current of a PEM electrolysis stack in response to higher current command to the power supply. The stack responds rapidly, in less than a tenth of a second. Figure 2, right, shows the stack current in response to a simulated wind profile input. Two stacks follow the profile, while the third is operated at steady state. PEM electrolyzers can therefore go from idle to full current in seconds. They can turn down to a minimum current point, without hazardous levels of hydrogen permeating into the oxygen stream. At any given differential pressure of hydrogen, the hydrogen flux across the membrane is relatively constant; the hydrogen concentration in the oxygen compartment due to diffusion is highest at low current when there is less oxygen being produced for dilution and for the recombination catalysts to work effectively. PEM stacks can also operate at over 100% of the rated capacity in some cases. While typical operating current densities for commercial electrolyzers range from 1 to 2 A/cm2, several electrolyzer companies have tested cells and stacks at higher current densities with no mass transport limitations. Figure 3 shows operation of PEM cells at 5 A/cm2 with little decay over thousands of hours, even for thicker membranes where the cell voltage exceeds 2.5V. Some researchers have tested even higher current densities; for example, 3M has measured polarization curves to higher than 15 A/ cm2 leveraging nanostructured thin film catalyst layers.6 Although the 3M work has primarily focused on ambient pressure operation and therefore may not be directly comparable to pressurized cells in terms (continued on next page) 67

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of durability, the data are a good demonstration of the catalyst activity and reactant management. As shown in Fig. 4, there is no evidence of mass transport limitations even at these high current densities. Although these data provide confidence in future capital cost reduction for PEM electrolysis through more effective utilization of the stack materials, the achievable current densities must be balanced against efficiency losses. Currently, electricity costs represent about 70–80% of the total cost (operating and capital cost) of PEM electrolysis. Increasing the required input power (decreasing efficiency) to decrease capital cost therefore only makes sense if the decrease in capital cost is large enough to make up for the increased electricity cost.7 This scenario becomes more and more likely as the electricity cost and the capacity factor go down, which often happens together. For example, excess solar power generated in the middle of the day may be very inexpensive but it is not available very often. If the electrolyzer only operates when the most inexpensive electricity is available, the capacity factor is likely to be too low to be practical, because the effective capital cost becomes so high. If the capacity factor is 10%, for example, the electrolyzer effectively costs 9 times as much per kilogram of output as a system operating at 90% capacity factor. Therefore, for grid applications where the capacity factor is high, operating at high current density may not provide enough cost savings to compensate for the increased electricity costs, but in a renewable energy application where the electricity cost is only $0.01–0.02/kWh and the electrolyzer only operates 25–30% of the time, increasing the current density could be an effective means of reducing hydrogen cost.

Currently, the estimated PEM electrolyzer cost is $1000–1400/ kW with clear pathways to $400/kW. The US Department of Energy (DOE)’s ultimate goal is $150/kW, in order to achieve the $1/kg H2 target set in its Hydrogen Energy EarthShot initiative. Catalyst and membrane costs comprise up to 50% of the stack cost when the stack price can be lowered to $300–400/kW. In PEM electrolysis, the hydrogen evolution reaction (HER) happening at the cathode is kinetically fast; therefore, it is feasible that even low platinum (Pt) loading (<0.1 mg/cm2) can ensure small overpotential at the cathode based on the progress from PEM fuel cells. However, at the anode, the oxygen evolution reaction (OER) is extremely sluggish, thus requiring the use of PGM catalysts like iridium black (Ir) or iridium oxide (IrO2). Currently, commercial PEM electrolyzers use high Ir loading (> 2 mg/cm2).8 The reduction of Ir loading in PEM electrolyzers can serve at least two purposes. First, given the high price of Ir ($5000/oz), Ir loading reduction by an order magnitude (to 0.2 mg/cm2) can help to lower the capital cost. In addition, Ir is scarce in the earth’s crust (0.0003 ppm) and annual Ir production is only 7–10 tons globally. Therefore, high Ir loading will be a barrier to the large-scale manufacture of PEM electrolyzers.9 There has been much effort to develop highly active OER catalysts to decrease or completely eliminate Ir loading.10–13 However, most OER activities of these catalysts were only demonstrated using rotating disk electrodes (RDEs); full device performance has not been well demonstrated, partially due either to low electronic

Getting to Cost Targets PEM electrolysis has high potential for cost reduction, as demonstrated by the fuel cell industry, which uses very similar PEM devices. Much less investment to date has been focused on electrolyzer manufacturing, and the similarities with fuel cells provide a head start in understanding how to reduce costs. Currently, electrolyzers have much higher loadings of platinum group metal (PGM) catalysts and much thicker membranes than fuel cells, close to an order of magnitude in each case. While ultimately the electrolyzer may require somewhat higher material usage due to specific cell conditions like differential pressure, full hydration, and high cell potential, it is likely that membrane thickness and catalyst usage can be reduced by several times. Optimization of other components and investment in manufacturing are needed to enable these improvements. Increased system scale will also help to reduce the balance of plant costs. 68

Fig. 3. Operation of PEM cells at 5 A/cm2. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Fig. 4. PEM electrolysis at high current density using 3M NSTF MEA.6

conductivity of these catalysts or to poor interaction between the catalyst and ionomer binder. Nevertheless, there are some validated OER catalysts in the Membrane Electrode Assembly (MEA) level. Giner developed a catalyst based on Ir or IrOx dispersed on tungsten doped TiO2.14 3M developed Ir nanostructured thin film (NSTF) that utilizes an organic pigment whisker as a support.6 Both catalysts can lower the Ir loading of commercial PEM electrolyzers by an order of magnitude without compromising the cell performance. They also demonstrated good catalyst durability over thousands of hours. Most recently, the MEA performance of nanoporous Ir nanosheets (npIrx-NS) exceeds that of a commercial Ir catalyst at loadings as low as 0.06 mg/cm2 while showing negligible performance loss after 50,000 accelerated stress test cycles.15 However, longer term durability of these catalysts still needs to be verified before they can be used in commercial PEM electrolyzers. Indeed, for low Ir loading electrodes, this long-term durability can be a concern. It has been shown that during electrolysis operation, significant amounts of Ir particles migrated or diffused from the anode to the membrane and even to the cathode.16 The loss of Ir may not be an issue for PEM electrolyzers with high Ir loading; however, when the Ir loading is reduced to below 0.2 mg/cm2, continuous depletion of the Ir from the anode can lead to electrolyzer failure. In addition, at low Ir loading, impurities accidentally introduced from the deionized water system can cause ultimate failure of the electrolyzer system. Therefore, there is a clear tradeoff between the Ir loading reduction and stack lifetime. Membranes are another important component of the cost of PEM electrolyzers. Compared to PEM fuel cells, the cost of membranes for PEM electrolyzers is far more significant because of the increased membrane thickness in the latter. In commercial PEM electrolyzers, 125–175 µm (e.g., Nafion 115 and 117) membranes are used, compared to 20 µm membranes used in PEM fuel cells. Thicker membranes are necessary to reduce H2 crossover at high differential pressures between H2 and O2. However, this thickness does incur the penalty of lower electrical efficiency and higher capital cost. For Nafion 115, the area specific resistance (ASR) at 80°C and wet condition is ~ 0.1 Ohm-cm2, which causes 500 mV voltage loss at 5 A/cm2. Reducing the thickness of the membrane by half can lower overpotential by 250 mV and also reduce the membrane cost. However, the thinner membrane can lead to higher H2 crossover, thus reducing faradaic efficiency and introducing a potential safety hazard due to the mixture of H2 and O2. There are two ways to address membrane-related challenges. To reduce membrane-associated ohmic resistance, low equivalent weight (EW) membranes with high proton conductivity can be adopted. However, these membranes may have poor chemical stability or a higher swelling ratio upon water uptake. To reduce membrane thickness without increasing H2 crossover, the membrane can be mechanically reinforced. For example, a low EW ionomer can be incorporated into a dimensionally stabilized membrane (DSM) that uses engineering plastics that offer 20–40 times higher tensile strength than Nafion.17 DSMs exhibit remarkable mechanical strength and dimensional stability during The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

changes in relative humidity and temperature. They also provide nontortuous, through-plane paths for ionic transport, thus minimizing the conductivity penalty of the support structure. In addition, as the Nafion membrane becomes thinner, radical attack on the polymer backbone or side chains can become a concern. Therefore, Chemours is developing mitigated membranes with gas recombination catalysts and radical scavengers.18 However, these developmental membranes may potentially incur high cost and their long-term durability needs further validation using the commercial PEM electrolyzer platform. In PEM electrolyzers, Ti-based porous transport layers (PTLs) are used at the anode and carbon-based gas diffusion layers (GDL) are used at the cathode. Carbon materials cannot be used at the anode because the high operating voltage can oxidize carbon rapidly. In a PEM electrolyzer, the most widely used anode PTLs are titanium in the form of sintered porous media, which are expensive and difficult to find commercially. For this reason, the estimated cost of Ti-PTLs in a PEM electrolyzer could be 10–30 times higher than corresponding raw Ti powders. A positive change is that the high demand for mass manufacturing of PEM electrolyzers also accelerates their supply chains; thus, the price of Ti-PTLs has been reduced significantly recently. However, the pore size and structure of current anode Ti-PTLs are empirically based, and there has been only limited rational design of the anode PTLs to maximize electrolyzer performance. A two-dimensional (2-D) multi-physics model was established for a PEM electrolyzer to describe the twophase flow.19 The model investigated the impact of PTL thickness on liquid water saturation and local current density. It found that the PTL under the land may have much lower liquid saturation than that under the channel due to land blockage. Experimentally, PTL thickness, porosity, and tortuosity have been found to significantly impact liquid water access and oxygen removal from/to the catalyst layer (CL), in addition to controlling the utilization of the catalyst layer’s active sites to a certain extent.20–22 Conventionally, Ti PTLs were coated with noble metals (Au, Pt, Ir) to increase their corrosion resistance. It was discovered that using Ir as a protective layer with a loading of 0.025 mg/cm2 on the PTL would be sufficient to achieve the same cell performance as PTLs with a higher Ir loading.23 This Ir loading was a 40-fold reduction over the Au or Pt loading that typically has been used for protective layers in commercial PEM electrolyzers. Therefore, the proper construction of a multifunctional interface between a membrane and a PTL can produce superior performance and efficiency in PEM electrolyzers. Another challenge is that Ti sinters are stiff materials that may result in a poor interface between the anode PTL and the electrode. Therefore, more flexible Ti-PTLs like Ti felts and Ti meshes should ideally be developed for PEM electrolyzers, if their strength requirements can be met. The cost of PEM electrolyzers is determined not only by the materials, but also by the manufacturing process. Current PEM electrolyzer manufacturing is largely based on small batch processes that are labor intensive. Multiple processes for PEM electrolyzers can be automated to reduce labor costs. For example, automated processes developed for PEM fuel cells can be adapted for PEM electrolyzers, including roll-to-roll (R2R) coating, in-line defect inspection, and automated stacking. The cost of PEM electrolyzers will be reduced by mass production which in turn spurs process automation. In the US, both Plug Power and Nel have kicked off multi-MW PEM electrolyzer manufacture. In Germany, Europe’s largest PEM hydrogen electrolyzer has begun operation at Shell’s Energy and Chemicals Park in Rheinland. In Spain, energy company Iberdrola has teamed up with Cummins to develop large-scale green hydrogen plants that can produce 500 MW PEM electrolyzers annually. Figure 5 shows a simulated 1 MW PEM electrolyzer stack cost breakdown projected based on an annual production rate.24 When mass production is implemented, the stack cost can drop significantly. Most costs will be reduced at the 1GW scale. When annual production is further increased to 50 GW, the stack cost reduction is relatively small. This figure also shows that at large-scale production of 1–50 GW, the MEA cost dominates, accounting for up to 50% of the total stack cost. (continued on next page) 69

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Importance of Accelerated Tests and Defined Protocols Finally, to accelerate the speed of electrolyzer development, structured approaches to testing and characterization are needed. Due to the long expected lifetimes of electrolyzer products, accelerated stress tests (AST) are needed to predict long-term performance before implementation. This type of stress testing also helps to predict the impact of varying field conditions or material properties on reliability. In addition, because one viable application of PEM electrolyzers is integration with renewable energy, the intermittency of renewables must be considered. Furthermore, for effective collaboration and acceleration of development through teamwork, standard tests and baselines need to be defined. These areas should be part of ongoing research and development programs, along with the materials and manufacturing development described above. In PEM electrolyzers, the system can degrade via different mechanisms, depending on its components. For the catalysts, the primary degradation mechanism is Ir particle migration or diffusion across the membrane and onto the cathode, thus leading to catalyst loss and anode thinning. This phenomenon not only reduces catalyst active sites, but also compromises the contact between the anode and membrane. Another degradation mechanism could be catalyst poisoning. If the water pretreatment system partially fails, impurities like cations or anions from the water can poison the Ir and Pt catalysts, resulting in their activity loss. For the membrane, there could be physical and chemical degradation. Like PEM fuel cells, the membranes of PEM electrolyzers may be subject to attack from peroxide radicals causing scission of PFSA main or side chains due to mechanisms identified for fuel cell conditions.25 The chemical degradation of the PEMs can lead to gradual loss of their mechanical integrity and a pinhole or complete membrane failure. Therefore, O2 at the anode and H2 at the cathode could mix, causing system failure and even explosion. Other degradation mechanisms of PEM electrolyzers include the oxidation of the Ti sinter or Ti bipolar plates, causing high electronic resistance of these components and increased interfacial resistance between these components and membranes or electrodes. AST protocols are necessary to rapidly study the degradation mechanisms of PEM electrolyzer components, but their development is still in the early stage. Compared to PEM fuel cells, PEM electrolyzers have different operating modes and dynamics, particularly when integrated with the intermittency of renewable energy. The impact of voltage cycling on a PEM electrolyzer was previously reported to cause Ir diffusion/migration, which caused significant anode thinning due to loss of Ir and Ir particle redeposition in the membrane under high voltage hold and voltage cycling.16 The impact of intermittent operation on the lifetime and performance of a PEM electrolyzer has also been studied.26 In this work, an AST mimicked a fluctuating power supply by operating the electrolyzer cell between 3 A/cm2 and 0.1 A/cm2, alternating with idle periods, and the cell rested at open circuit voltage (OCV). A variety of AST protocols— including triangle, square-wave and sawtooth—were studied.27 It was found that low catalyst loading and high cell potential were critical to cause degradation regardless of test profile. Electrolyzer operation with model wind and solar profiles resulted in less severe performance losses compared to triangle and square-wave potential cycling due to the lower cycling frequency of the renewable profiles. So far, there are no universal AST protocols for PEM electrolyzers, making it difficult to compare data between systems. To remedy this, the International Energy Agency (IEA) has organized multiple workshops on H2 and electrolysis to coordinate an international effort on ASTs for PEM electrolyzers. These workshops provide insightful guidance on the study of component degradation mechanisms and mitigation. Recently, the DOE Hydrogen and Fuel Cell Technologies Office launched H2NEW, a consortium led by US National Labs whose mission, in part, is to develop comprehensive ASTs for all the components in a combination of advanced characterizations amid the 70

Fig. 5. Manufacturing cost curve for 1-MW PEM electrolyzer stack at different scales.24

ASTs. It is anticipated that the developed ASTs can be implemented by different labs for data comparison. It would be very meaningful to establish the relationship between the AST and real lifetime.

Conclusion PEM water electrolysis has developed into a mature technology for green H2 production when integrated with renewable energy. It demonstrates multiple advantages, including high efficiency, high operating density, fast dynamic response, and the ability to operate at high and differential pressures. Cost and durability are still barriers to limit the large-scale implementation of PEM electrolyzers. Major components, including catalysts, membranes, and PTLs, hold promise for significantly reducing the cost of PEM electrolyzers. Collaborative ASTs across different labs are highly desirable to study the degradation of PEM electrolyzers and to further improve their durability.

Acknowledgment The authors acknowledge funding from the Department of Energy, Office of Ene rgy Efficiency and Renewable Energy, Hydrogen and Fuel Cells Technology Office under Contract numbers DE-EE0008092 (KA), DE-AC02-05CH11231 (ND), DE-AC3608GO28308 (KH), and DOE SBIR/STTR Programs Office, under the Contract number DE-SC0007471 (HX). We also thank Dr. Krzysztof Lewinski from 3M for providing data in Fig. 4. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information,

Fig. 6. TEM images of aged anode after voltage cycling (1.4 V to 2.0 V): Near Anode (Image taken by Dr. Karren More at ORNL). Small dots in the membrane represent Ir particles from the anode.16 The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. © The Electrochemical Society. DOI: 10.1149/2.F16214IF

About the Authors Katherine Ayers, Vice President, R&D, Nel Hydrogen, South Glastonbury, CT, U.S. Education: BS in Chemistry/Chemical Physics (UCSD), PhD in Chemistry (California Institute of Technology). Research Interests: Water and CO2 electrolysis. Pubs + Patents: 40+ papers, h-index: 29, 2 patents. Awards: R&D Award at DOE Annual Merit Review, Hydrogen Technologies—Production (2021); Fuel Cell Seminar Program Award (2015); ACS Women Chemists Committee Rising Stars Award (2014). Work with ECS: Energy Technologies Division Vice Chair (previously served as Secretary and Treasurer); ISTS Committee Member (2018–2020); Fellow, class of 2020. Website: https://www.nelhydrogen.com https/orcid.org/0000-0003-3246-1744 Nemanja Danilovic, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. Education: BASc in Materials Engineering (University of Toronto); PhD in Materials Engineering (University of Alberta). Research Interests: Water and CO2 electrolysis. Pubs + Patents: 48 papers, h-index: 27, 3 ECS publications. Awards: ECS Toyota Young Investigator Award 2019. Work with ECS: Energy Technology Division Affiliate. Website: https://daniloviclab.lbl.gov/ https://orcid.org/0000-0003-2036-6977 Kevin Harrison, Program Manager V, Research, National Renewable Energy Laboratory, Golden, CO, U.S. Education: BS in Electrical Engineering (University of Rochester), MS in Electrical Engineering (University of North Dakota), PhD in Energy Engineering (University of North Dakota). Research Interests: Water electrolysis, Renewable hydrogen, Biomethanation, CO2 utilization. Pubs + Patents: 22 papers, 40 presentations, 3 book chapters. Awards: R&D100 Nominated, NREL Staff Award - Technology Transfer IP Licensing. Website: https://www.nrel.gov/ Hui Xu, Giner, Inc., Aburndale, MA, U.S. Education: BS in Chemical Engineering (Wuhan Institute of Technology), PhD in Chemical Engineering (University of Connecticut). Research Interests: Electrolysis and fuel cells. Pubs + Patents: 46 papers, h-index: 25, 2 patents. Awards: Key Contributor to 2021 Special Recognition Award from DOE H2 Program Annual Merit Review Meeting; Inducted into the University of Connecticut Academy of Distinguished Engineers (2020). Work with ECS: Energy Technologies Division Treasurer; Guest editor for three JES special focus issues. Website: https://www.ginerinc.com/ https://orcid.org/0000-0001-6829-7187 The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

References 1. M. Carmo, D. L. Fritz, J. Mergel, and D. Stolten, Int. J. Hydrog. Energy, 38, 4901 (2013). 2. K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar, and M. Bornstein, Annu. Rev. Chem. Biomol. Eng., 10, 219 (2019). 3. P. Lettenmeier, R. Wang, R. Abouatallah, B. Saruhan, O. Freitag, P. Gazdzicki, T. Morawietz, R. Hiesgen, A. S. Gago, and K. A. Friedrich, Sci. Rep., 7, 44035 (2017). 4. National Aeronautics and Space Administration, (1996). 5. Y. N. Regmi, X. Peng, J. C. Fornaciari, M. Wei, D. J. Myers, A. Z. Weber, and N. Danilovic, Energy Environ. Sci., 13, 2096 (2020). 6. K. A. Lewinski, D. van der Vliet, and S. M. Luopa, ECS Trans., 69, 893 (2015). 7. A. Badgett, M. Ruth, B. James, and B. Pivovar, Curr. Opin. Chem. Eng., 33, 100714 (2021). 8. N. Danilovic, K. E. Ayers, C. Capuano, J. N. Renner, L. Wiles, and M. Pertoso, ECS Trans., 75, 395 (2016). 9. Z. Taie, X. Peng, D. Kulkarni, I. V. Zenyuk, A. Z. Weber, C. Hagen, and N. Danilovic, ACS Appl. Mater. Interfaces, 12, 52701 (2020). 10. Y. Yao, S. Hu, W. Chen, Z. Huang, W. Wei, T. Yao, R. Liu, K. Zang, X. Wang, G. Wu, W. Yuan, T. Yuan, B. Zhu, W. Liu, Z. Li, D. He, Z. Xue, Y. Wang, X. Zheng, J. Dong, C. Chang, Y. Chen, X. Hong, J. Luo, S. Wei, W. Li, P. Strasser, Y. Wu, and Y. Li, Nat Catal, 2, 304 (2019). 11. L. C. Seitz, C. F. Dickens, K. Nishio, Y. Hikita, J. Montoya, A. Doyle, C. Kirk, A. Vojvodic, H. Y. Hwang, J. K. Norskov, and T. F. Jaramillo, Science, 353, 1011 (2016). 12. H. N. Nong, T. Reier, H.-S. Oh, M. Gliech, P. Paciok, T. H. T. Vu, D. Teschner, M. Heggen, V. Petkov, R. Schlögl, T. Jones, and P. Strasser, Nat. Catal., 1, 841 (2018). 13. N. Danilovic, R. Subbaraman, K. C. Chang, S. H. Chang, Y. Kang, J. Snyder, A. P. Paulikas, D. Strmcnik, Y. T. Kim, and D. Myers, Angew. Chem. Int. Ed., 53, 14016 (2014). 14. S. Zhao, A. Stocks, B. Rasimick, K. More, and H. Xu, J. Electrochem. Soc., 165, F82 (2018). 15. S. Chatterjee, X. Peng, S. Intikhab, G. Zeng, N. N. Kariuki, D. J. Myers, N. Danilovic, and J. Snyder, Adv. Energy Mater., 11, 2101438 (2021). 16. H. Xu, DOE AMR 2016 (2016). 17. C. K. Mittelsteadt and A. B. LaConti, U.S. Patent 20140342271A (2011). 18. A. Park, DOE AMR 2021 (2021). 19. Q. Chen, Y. Wang, F. Yang, and H. Xu, Int. J. Hydrog. Energy, 45, 32984 (2020). 20. X. Peng, P. Satjaritanun, Z. Taie, L. Wiles, A. Keane, C. Capuano, I. V. Zenyuk, and N. Danilovic, Adv. Sci., 2102950 (2021). 21. Z. Kang, G. Yang, J. Mo, Y. Li, S. Yu, D. A. Cullen, S. T. Retterer, T. J. Toops, G. Bender, B. S. Pivovar, J. B. Green, and F.-Y. Zhang, Nano Energy, 47, 434 (2018). 22. T. Schuler, J. M. Ciccone, B. Krentscher, F. Marone, C. Peter, T. J. Schmidt, and F. N. Büchi, Adv. Energy Mater., 10, 1903216 (2020). 23. C. Liu, K. Wippermann, M. Rasinski, Y. Suo, M. Shviro, M. Carmo, and W. Lehnert, ACS Appl. Mater. Interfaces, 13, 16182 (2021). 24. A. T. Mayyas, M. F. Ruth, B. S. Pivovar, G. Bender, and K. B. Wipke, Manufacturing Cost Analysis for Proton Exchange Membrane Water Electrolyzers, National Renewable Energy Lab. (NREL), Golden, CO (United States), (2019). 25. F. D. Coms, H. Xu, T. McCallum, and C. Mittelsteadt, ECS Trans., 64, 389 (2014). 26. A. Weiß, A. Siebel, M. Bernt, T.-H. Shen, V. Tileli, and H. A. Gasteiger, J. Electrochem. Soc., 166, F487 (2019). 27. S. M. Alia, S. Stariha, and R. L. Borup, J. Electrochem. Soc., 166, F1164 (2019).

ECS Toyota Young Investigator Fellowship Call for Applications

The ECS Toyota Young Investigator Fellowship is awarded to young professionals and scholars pursuing research in batteries, fuel cells and hydrogen, and future sustainable technologies.

At least one $50,000 fellowship is available annually. To learn more and apply, visit www.electrochem.org/toyota-fellowship

Application Deadline: January 31, 2022

Hydrogen at Scale Using Low-Temperature Anion Exchange Membrane Electrolyzers by Sanjeev Mukerjee, Yushan Yan, Hui Xu

mong the two commercial low-temperature electrolyzers, alkaline liquid electrolyzers (AELs) and proton exchange membrane electrolyzers (PEMELs), the AELs have the largest market share with approximately 2M metric tons of high-purity hydrogen produced annually worldwide. AELs are typically two electrodes composed of Raney Ni, Ni-plated steel, or Ni/Stainless steel mesh in an aqueous electrolyte (typically 4.5-7.1 M KOH) with a microporous diaphragm of glass-reinforced polyphenylene sulfide (Ryton) or polysulfonebonded ZrO2 membrane (Zirfon) for OH- transport and capable of gas separation at moderate differential pressures. AEL stacks of 10–1500 Kg H2/day have been developed by companies such as Nel, McPhy, Teledyne, and IHT. They are very durable with a system lifetime of 30–40 years. The principal issues are high ohmic resistance because of gas bubble formation and the use of thicker diaphragms lowering voltage efficiency and limiting current density performance. In addition, the use of corrosive liquid electrolytes adds to system-level costs. Typically, the pressure ranges available are low and hence the need for additional compression technologies for hydrogen storage and transportation. In comparison with AELs, PEMELs possess advantages that include high current density and voltage efficiency, fast dynamic response, compact cell design, and the ability to be pressurized, hence avoiding the extra cost of compression (lower system cost). However, the principal disadvantage of PEMELs is the limitation of the materials to platinum-group metals, especially the use of iridium (Ir) at the anode. Ir is not only expensive, but it is also scarce in

Fig. 1. Schematic of electrolysis in AEM membranes. GDL: gas diffusion layer, MPL: microporous layer, CL: catalyst layer. Used with permission from: https://weberlab.lbl.gov/electrolyzers The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

the earth’s crust, thus driving up the cost of PEM electrolyzers and making their widespread deployment impractical. In addition, the need for titanium-based stack components further increases the capital cost of the system. In contrast to PEMELs, anion exchange membrane electrolyzers (AEMELs) combine the features of AELs and PEMELs,1 thus possessing advantages of both.2 A schematic of AEMEL operation is shown in Fig. 1. In comparing AEMELs with AELs and PEMELs, denser hydroxide ion exchange membranes replace the microporous diaphragm separators present in AELs, thus enabling H2 pressurization and operation at high current density. In addition, they replace precious metals in PEMELs with earth-abundant and inexpensive materials, thus making them more affordable and scalable.

Materials and Components for AEM Electrolyzers Membranes and Ionomers

The recent advent of novel anion exchange membranes has resulted in renewed interest in the development of AEMELs. Such membranes have hydroxide conductivities close to those of state-ofthe-art PEMs such as the prototypical perfluorinated sulfonic acidbased polymer electrolyte operating in the acidic domain. Several reviews cover the wide diversity of membranes that have been recently developed.3-5, 6, 7 In general, polymer anion exchange membranes consist of three structural components: (1) Cation, (2) Backbone, and (3) Linker. Among the cations (which constitute the ion exchange sites) that have been developed so far are alkyl trimethylammonium, cyclic ammonium multi-substituted imidazolium and piperidinium, cobaltocenium, and phosphonium cations. For the backbone, polyaromatics are thus far the most employed. All carbon-based ether-free backbones have demonstrated the highest alkaline stability among their peers to date.8 In this context are reports of unique interactions between the ionomer and the electrocatalyst from Kim et. al.9 In the case of the linker, neutral linkers with alkyl chains or heteroatoms such as oxygens, nitrogen, and triazoles have all displayed reasonable ex-situ alkaline stability. Evidently the field of anion exchange membrane materials has advanced greatly, enabling stable membranes at 80–90°C and alkaline stability in 1 M KOH autoclave tests at a change from 100°C for 2000 hrs. Currently, simple alkyl quaternary ammoniums continue to be the most studied and are among the most stable classes of cations. They are compact and have low molar mass compared to resonance-stabilized or heavy-element cations. These advantages of the simple alkyl quaternary ammoniums allow for a greater degree of ion exchange capacity. Current efforts have led to materials sets collectively approaching properties of the gold standard Nafion® membranes, including Versogen, Orion Polymer, Ionomr, Ecolectro, Carbon Dioxide Materials, and Xergy.10 The major challenge for AEMs is the mechanical and chemical degradation under high operating voltage and liquid water soak. A poly(aryl piperidium)-based AEM developed by Versogen has demonstrated simultaneous chemical and mechanical durability,1 as shown in Fig. 2. Poly(aryl piperidinium) polymers introduce an alkaline-stable cation, piperidinium, into a rigid aromatic polymer backbone that is free of ether bonds. Anion exchange membranes (continued on next page) 73

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(AEM) formed from PiperION polymers exhibit superior chemical stability, anion conductivity, decreased water uptake, good solubility in selected solvents, and improved mechanical properties.1

OER and HER Catalysts

Oxygen Evolution Reaction (OER) Electrocatalysts4There have been substantial studies of OER catalysts in alkaline media. Several recent reviews extensively describe these efforts.11, 12 In general, the classes of materials developed can be classified as (1) precious metal oxides, mostly IrOx and RuOx; (2) perovskites (ABO3, where A is alkaline and/or a rare earth metal, and B is a transition metal); (3) spinels (general formula A/B/2O4, where A/ and B/ are usually group 2, group 13, and first-row transition elements); (4) layered-type metal oxides which include metal oxides and oxyhydroxides (MOOH), where the transition happens between beta-Ni(OH)2 to beta-NiOOH (OER mode) to a high overpotential state of gamma-NiOOH back to beta-Ni(OH)2 via alpha-Ni(OH)2; (5) mixed-metal hydroxides such as a-Fe100-y-zCoyNizOx; (6) chalcogenides; (7) metal pnictides, such as metal nitrides and phosphides; (8) organometallic compounds; and (9) non-metal compounds which are mostly carbon-based materials with heteroatom dopants. In general, among the noble metals, RuOx is unstable at both ends of the pH scale wherein at high overpotentials formation of RuO4 and eventual dissolution occurs. IrOx is more stable; however, it is highly unsustainable from the points of view of cost and availability. Among the other classes of materials that have been extensively studied and are most viable are the metal perovskites and mixed-metal layered double hydroxide (LMDH) materials. Both are easy to synthesize and generally meet sustainable low-cost considerations. Both classes of materials offer a high degree of tunability. In the LMDH class of materials, doping allows for refined tuning to achieve a very high degree of OER activity. The activity of most of the above-mentioned OER catalysts, especially the LMDH and perovskites in the alkaline operating range of pH 13–14, shows superior activity as compared to the IrOx-class of noble metal catalysts. Other classes of materials mentioned above do not appear to rival the activity of the perovskites and LMDH. Mechanistically, OER on these materials can be described by a schematic shown in Fig. 3. In general, the mechanism for OER in alkaline pH can be described as (overall) with the following elementary steps:

M OH MOH

(1)

MOH OH MO H 2 O l

(2)

2 MO 2 M O2 g

(3)

MO OH MOOH e

(4)

MOOH OH M O2 g H 2O l

electrode. The availability of stable ionomers in the market is very limited and the interaction between the OER catalysts and anion exchange ionomers needs further investigation to attain optimal electrode structure. The emergence of AEM companies can help resolve the second barrier. HER Electrocatalysts4In alkaline media, HER presents a particular challenge: at high pH HER is more sluggish because of the external energy needed to generate H+ from the catalytic dissociation of water,13-15 whereas in acidic media H+ is freely available.16, 17 In alkaline media, a mechanistically HER mechanism can be described on the basis of three steps.18-20 Despite some ambiguity about whether the HER mechanism follows Volmer-Tafel or Volmer-Heyrovsky, it is generally accepted that the Volmer step occurs first, breaking the water molecule before the hydrogen recombination occurs to form H2. Some publications, however, claim that a Volmer-Heyvrosky pathway is preferred in alkaline media21, 22 due to smaller energy barriers as compared to the Volmer-Tafel pathway, see Eq. 6 & 7. Also, the side product (OH–) needs to be removed from the surface efficiently to complete the Volmer step.

Ni e H 2O Ni H ads OH

Ni H ads H 2O e H 2 OH Ni (Heyrovsky)

(6) (7)

As reported earlier by Markovic et al.,23 oxophillic sites facilitate the adsorption and dissociation of water into Hads and OHads according to the bifunctional mechanism. The oxophillic sites perform the important function of weakening the H-OH bond and thereby facilitating the transport of the resulting OHads away from the (Ni0) active site (eq. 8).

Ni OH 2 H 2O Ni OH 2 OH 2,ads

(8)

Ni Ni OH 2 OH 2,ads Ni OH 2 OH ads Ni H ads (9) Bifunctionality by metal/metal oxides (MMOx) is not uncommon, having been invoked for the water-gas shift reaction,24, 25 proton hopping,26 and carbon monoxide oxidation.27 Although the logic of the bifunctional HER mechanism has been well known for decades, its true delineation was demonstrated by Markovic et al. using a Pt surface decorated with Ni(OH)2 clusters, resulting in an increase of HER activity by a factor of eight.13

O2(G) + H+ + H2O(l)

(5)

In most cases these PGM-free catalysts demonstrate remarkable activity at the RDE level; however, their application in real electrodes or membrane electrode assembly (MEAs) is very limited due to at least two reasons. First, many of these catalysts do not have sufficient electronic conductivity, therefore, they incur significant ohmic resistance when integrated with thick electrodes. Second, real MEAs operating with pure water (without supporting electrolyte) need to be mixed with ionomer to enhance the OH- conductivity in the

(Volmer)

O2(g) +H2O(l) + OHM-OOH H+

H+ + e -

e½ O2(g) M-OH

+ OH-

OH-

H2O(l)

+ OH-

M-O H+

Fig. 2. Chemical structure of Versogen’s PAP (PAP-TP-85) membranes. Used with permission from: https://www.sciencedirect.com/science/article/ pii/S0376738819324184. 74

Fig. 3. The OER mechanism for acid (blue line) and alkaline (red line) conditions. The black line indicates that the oxygen evolution involves the formation of a peroxide (M–OOH) intermediate (black line) while another route for direct reaction of two adjacent oxo (M–O) intermediates (green) to produce oxygen is possible as well. Used with permission from: Chem. Soc. Rev., 46, 337 (2017). The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Fig. 4. Schematic depicting a bifunctional mechanism using a functionalized mono-metallic surface using Ni. Note the use of oxophilic moieties for enabling water transport to the Ni0 surface for hydride formation.37

3D transition metals such as nickel (Ni) possess a 3D band that spans the Fermi level, thus satisfying the Sabatier principle, which makes them attractive candidates for HER catalysts in an alkaline environment. Additionally Ni exhibits hydrogen binding energy close to that of Pt despite having a lower activity toward HER.28 Ni also has the highest resistance to corrosion in an alkaline environment. These properties make Ni an excellent candidate due the close affinity for transfer of charge from the adsorption site to the proton.29-31 Therefore, in terms of rational design, the close juxtaposition of Ni and NiOx provides an excellent alternative to Pt HER catalysts. HER performance by Ni/NiOx catalysts has been reported by Wang et al.,32 Gong et al.,33 and Lovell et al.,34 both unsupported and loaded onto nanostructured carbon with the two latter studies reporting a performance close to that of Pt. However, the stability of these catalysts has not been adequately addressed. Gong et al.33 reported a degradation rate of 2.4 mV/hr in a full electrolysis cell. However, this study was conducted at 20 mA cm-2, a current density far too low to be comparable to actual operating conditions. Wang et. al.32 highlight the importance of creating a favorable Ni: NiOx ratio, noting that above 1:2 there is a detrimental impact on performance due to an inadequate specific surface area of Ni for hydrogen adsorption and recombination. While the previous studies demonstrate the ability to and importance of creating a catalyst with a favorable ratio of Ni: NiOx, they do not show an ability to maintain it: exposing the catalyst to anodic potentials or even ambient conditions over time could create additional NiOx sites. A new class of materials has been described, referred to as a functionalized monometallic Ni-based catalyst, where layers of graphene introduced during synthesis envelop the Ni0 particles, making these moieties resistant to oxidative passivation and formation of deactivating metal hydride regions while maintaining a favorable ratio of Ni0 to NiOx.21, 35, 36 The efficacy of this catalyst has been demonstrated in the practical context of a full cell operated in a hydrogen pump configuration that exhibits superior alkaline HER activity and durability. Characterizations show that, unlike standard Ni or MMOx catalysts, whose surfaces are susceptible to poisoning through oxidation and hydride formation,21, 35-37 the surface of a functionalized Ni catalyst maintains stable HER activity even after anodic and cathodic polarization. This study is further embellished using synchrotron-based in situ x-ray absorption spectroscopy for probing the durability of the Ni surfaces for passivation and hydride formation and kinetic analysis of the HER reaction as qualitative support of the electrochemical data represented by RDE studies.37

Performance Status and Target AEM electrolysis can operate with or without the supporting electrolyte. Under Scenario 1 with a supporting liquid electrolyte like KOH or K2CO3, the AEM electrolyzer can be considered as an advanced AEL wherein microporous diaphragm separators are The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

replaced by AEMs. It should be noted that in this scenario the cathode is run without any liquid electrolyte and supporting electrolytes are restricted to the anode OER electrode. Herein the principal engineering challenge is that of operating the anode at high current density with the requirement of locally available hydroxyl ions becoming a challenge when using the less onerous carbonates. The AEM electrolyzer with KOH can achieve much higher current density than ALE. With these supporting electrolytes, cells can be operated with differential pressures like a PEM electrolyzer. However, further development is required in terms of reinforcement and cross linking. Under Scenario 2, no supporting electrolyte is used, so the AEM electrolyzer operates with pure water. This scenario, however, has challenges in terms of both ionomer stability at the anode and high current density operation. A comparison of noble and non-noble metal catalysts can be gleaned from Fig. 5.1 Here the performance of an AEM electrolyzer using a hexamethyl trimethyl ammonium-functionalized Diels– Alder polyphenylene (HTMA-DAPP) AEM developed by LANL is shown, which represents state-of-the-art AEM performance. With 1M NaOH, the performance of an AEM electrolyzer using a NiFe anode and a PtRu cathode approaches that of a PEM electrolyzer with pure water. However, without the NaOH solution, the performance of AEM electrolyzer with the same catalyst (NiFe/PtRu) is much worse, largely due to high OH- transport resistance in the electrode and membrane interface or in the electrode. The performance decays even more significantly when a PGM-free catalyst is used on both sides. For the AEM electrolyzer, we ultimately would like to reach a performance close to PEMEL, using a thick membrane (>80 µ m) that is less than 2.0 V at 2 A/cm2. Major AEM electrolyzer players include Enapter, Giner Inc, Alchemr, EvoION, Los Alamos National Laboratory, Versogen, and Northeastern University.

Efficiency Calculations Several excellent publications have reported various approaches to efficiency calculations.38-43 Typically, water electrolysis efficiency is calculated using the higher heating value of hydrogen (HHV). (continued on next page)

Fig. 5. AEM electrolyzer performance catalyzed by a PGM-free anode. The performance of MEAs employing PGM-free catalysts (the magnified region of the current density between 0.0 and 0.6 A cm-2, shown in the inset). AEM, HTMA-DAPP (26 μm thickness); anode, NiFe nanofoam (3 mg cm2 ); cathode, PtRu/C (50 wt% Pt, 25 wt% Ru, 2 mgPt cm-2) or NiMo/C (2 mgNiMo cm-2). The ionomer content at the cathode was 20 wt%. The performance was measured under ambient pressure at 60 °C for NaOH solution and 85 °C for pure water flowing in both the anode and the cathode. The performance of a state-of-the-art PEM electrolyzer11 is also shown. PEM electrolyzer, PEM 3 M 825 EW (50 μm thickness); anode, 0.25 mg cm-2 Ir-NSTF; cathode, 0.25 mg cm-2 Pt-NSTF measured at 80 °C. Used with permission from: Nature Energy, 5, 378 (2020). 75

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About the Authors

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Because the water is supplied to the cell in the liquid phase, efficiency E can be calculated by TN , this allows (ETN is the thermoneutral Ecell potential) the efficiency to be calculated at any current density. This approach gives an efficiency at 1.00 A/cm2 (shown in Fig. 5 to be 84%). This compares well with the best-in-class values in the range of 71%. Another measure of efficiency is faradaic efficiency. Faradaic efficiency can be described as the ratio of the experimentally evolved volume of gas (hydrogen or oxygen) and theoretically FH 2 (real) FH 2 (real) calculated volume of gas value, i.e., faraday . FH 2 (ideal) I (nF ) 1 The total cell efficiency is: cell voltage * Faraday . The theoretical volume of gas can be calculated using Faraday’s laws based on current density, electrolysis time, and electrode area by assuming 100% faradaic efficiency. The actual value can be measured using volumetric displacement or chromatographically. C 103 ml t (60 s ) I S V H Produced) V ( l ) ( Theoretical where, 2 M L min 2 F C R 273 T . VM

Roadmap for Achieving the DOE EarthShot Mission on Hydrogen The mission to achieve hydrogen at a cost of $1/kg requires an efficiency target of better than 43 kWhr/kg which requires a current density of at least 2 A/cm2 at or below 2 V with degradation under steady state operation of below 5µV/hr. As mentioned above, achieving this goal requires a concerted effort toward (a) improving materials design for both catalysts and membranes, (b) better design of ionomers, (c) the critical need for better electrode architecture and ink formulations, (d) improved current collectors, and (e) better system design which can either take care of shunt currents more efficiently, or involve an effort to operate without supporting electrolyte (i.e., in pure water). It is clear that the local concentration of hydroxyl ions at the anode (due to OER) is very close to the membrane electrode interface. This concentration falls exponentially away into the electrode (0-5 µm); as a result controlling bubble formation with efficient charge transfer is the critical parameter which will need attention in the future.

Acknowledgment The authors acknowledge funding from the Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cells Technology Office (DOE-EERE-HFTO) under contract number DE-AC02-05CH11231. SM gratefully acknowledges the support from the Department of Energy under grant # DEEE00008082. SM also acknowledges the support from members of various National Laboratories, notably Adam Weber and Ahmet Kusoglu (LBNL), Reese Jones (SNL), Bryan Pivovar (NREL). YY acknowledges the support from the Department of Energy, ARPA-E program (DE-AR0000771 and DE-AR0001149). HX acknowledges support from the Department of Energy, HFTO program (DEEE00069601 and DE-EE0008438). The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. © The Electrochemical Society. DOI: 10.1149/2.F17214IF 76

Sanjeev Mukerjee, Professor, Northeastern University, Department of Chemistry and Chemical Biology, Boston, MA, U.S. Education: MTech in Catalysis (Indian Institute of Technology, Kharagpur), MSc in Chemistry (Indian Institute of Technology, New Delhi), PhD in Analytical Chemistry (Texas A&M University) Research Interests: Electrolysis, Fuel cells, Sensors, Secondary storage. Pubs + Patents: 185 papers, h-index: 82, 9 patents. Awards: Fellow of the International Society of Electrochemistry (2019); Distinguished College Professor, Northeastern University (2015); Ford Motor Company University Research Professorship (2010). Work with ECS: Member since 1992. Chair of the ETD Research Award (2021-2022); Chair of the Srinivasan Research Award (2010–2011); Member of the ETD executive committee (10 years); Life Fellow (2014). Website: https://www.northeastern.edu/nucret/ https://orcid.org/0000-0002-2980-7655 Yushan Yan, Henry B. du Pont Chair of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, U.S. Education: BS in Chemical Physics (University of Science and Technology of China), PhD in Chemical Engineering (California Institute of Technology). Research Interests: Electrochemical engineering, Electrocatalysis, Polymer electrolytes, Electrochemical interface, Fuel cells, Electrolyzers, Flow batteries, Carbon capture. Pubs + Patents: 270 papers, h-index: 94, 20+ patents. Awards: Carl Wagner Memorial Award, ECS; R.H. Wilhelm Award, AIChE; Fellow of National Academy of Inventors, ECS and AAAS. Work with ECS: Member of ECS since 2000; Member of Energy Technologies Division; Life Fellow. Website: Yan.cbe.udel.edu; Versogen.com https://orcid.org/0000-0001-6616-4575 Hui Xu, Giner, Inc., Aburndale, MA, U.S. Education: BS in Chemical Engineering (Wuhan Institute of Technology), PhD in Chemical Engineering (University of Connecticut). Research Interests: Electrolysis and fuel cells. Pubs + Patents: 46 papers, h-index: 25, 2 patents. Awards: Key Contributor to 2021 Special Recognition Award from DOE H2 Program Annual Merit Review Meeting; Inducted into the University of Connecticut Academy of Distinguished Engineers (2020). Work with ECS: Energy Technologies Division Treasurer; Guest editor for three JES special focus issues. Website: https://www.ginerinc.com/ https://orcid.org/0000-0001-6829-7187

References 1. J. Wang, Y. Zhao, B. P. Setzler, S. Rojas-Carbonell, C. B. Yehuda, A. Amel, M. Page, L. Wang, K. Hu and L. Shi, Nature Energy, 4, 392 (2019). 2. R. Abbasi, B. P. Setzler, S. Lin, J. Wang, Y. Zhao, H. Xu, B. Pivovar, B. Tian, X. Chen, and G. Wu, Adv. Mater., 31, 1805876 (2019). The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

3. B. Motealleh, Z. Liu, R. I. Masel, J. P. Sculley, Z. R. Ni, and L. Meroueh, Int. J. Hydrogen Energy 46, 3379 (2021). 4. K. Yang, X. Chu, X. Zhang, X. Li, J. Zheng, S. Li, N. Li, T. A. Sherazi, and S. J. Zhang, Membr. Sci., 603 (2020). 5. I. Pushkareva, A. Pushkarev, S. Grigoriev, P. Modisha, and D. Bessarabov, Int. J. Hydrogen Energy, 45, 26070, (2020). 6. W. You, K. J. Noonan, and G. W. Coates, Prog. Polym. Sci., 100, 101177, 2020. 7. Z. Sun, B. Lin, and F. Yan, ChemSusChem, 11, 58, (2018). 8. E. J. Park and Y. S. Kim, J. Mater. Chem. A, 6, 15456 (2018). 9. I. Matanovic, S. Maurya, E. J. Park, J. Y. Jeon, C. Bae, and Y. S. Kim, Chem. Mater., 31, 4195 (2019). 10. J. Xiao, A. M. Oliveira, L. Wang, Y. Zhao, T. Wang, J. Wang, B. P. Setzler, and Y. Yan, ACS Catal., 11, 264 (2020). 11. M. Tahir, L. Pan, F. Idrees, X. Zhang, L. Wang, J.-J. Zou, and Z. L. Wang, Nano Energy, 37, 136 (2017). 12. N.-T. Suen, S.-F. Hung, Q. Quan, N. Zhang, Y.-J. Xu, and H. M. Chen, Chem. Soc. Rev., 46, 337 (2017). 13. R. Subbaraman, D. Tripkovic, D. Strmcnik, K.-C. Chang, M. Uchimura, A. P. Paulikas, V. Stamenkovic, and N. M. Markovic, Sci., 334, 1256 (2011). 14. N. Danilovic, R. Subbaraman, D. Strmcnik, K. C. Chang, A. Paulikas, V. Stamenkovic, and N. M. Markovic, Angew. Chemi., Int. Ed., 51, 12495 (2012). 15. B. Liu, Y. F. Zhao, H. Q. Peng, Z. Y. Zhang, C. K. Sit, M. F. Yuen, T. R. Zhang, C. Lee, and W. J. Zhang, Adv. Mater., 29, 1606521 (2017). 16. J. Wang, F. Xu, H. Jin, Y. Chen, and Y. Wang, Adv. Mater., 29, 1605838 (2017). 17. X. Li, P. F. Liu, L. Zhang, M. Y. Zu, Y.X Yang, and H. G. Yang, H. G., Chem. Commun., 52, 10566 (2016). 18. W. Sheng, H. A. Gasteiger, Y. and Shao-Horn, J. Electrochem. Soc., 157, B1529 (2010). 19. J. Durst, A. Siebel, C. Simon, F. Hasche, J. Herranz, and H. Gasteiger, Energy Environ. Sci., 7, 2255 (2014). 20. N. Krstajić, M. Popović, B. Grgur, M. Vojnović, and D. J. Šepa, J. Electroanal. Chem., 512, 16 (2001). 21. S. A. Machado, and L. Avaca, Electrochim. Acta, 39, 1385 (1994). 22. L. X. Chen, Z. W. Chen, Y. Wang, C. C. Yang, and Q. Jiang, ACS Catal., 8, 8107 (2018). 23. R. Subbaraman, D. Tripkovic, K.-C. Chang, D. Strmcnik, A. P. Paulikas, P. Hirunsit, M. Chan, J. Greeley, V. Stamenkovic, and N. M. Markovic, Nat. Mater. 11, 550 (2012).

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24. J. Rodriguez, S. Ma, P. Liu, J. Hrbek, J. Evans, and M. Perez, Sci., 318, 1757 (2007). 25. H. Q. Fu, H. Saltsburg, and M. Flytzani-Stephanopoulos. Sci., 301, 935 (2003). 26. L. R. Merte, G. Peng, R. Bechstein, F. Rieboldt, C. A. Farberow, L. C. Grabow, W. Kudernatsch, S. Wendt, E. Lægsgaard, and M. Mavrikakis, Sci., 336, 889 (2012). 27. J. Knudsen, L. R. Merte, G. Peng, R. T. Vang, A. Resta, E. Lægsgaard, J. N. Andersen, M. Mavrikakis, and F. Besenbacher, ACS Nano, 4, 4380 (2010). 28. W. Sheng, M. Myint, J. G. Chen, and Y. Yan, Energy Environ. Sci., 6, 1509 (2013). 29. M. Devanathan, and M. Selvaratnam, Trans. Faraday Soc., 56, 1820 (1960). 30. N. Krstajić, M. Popović, B. Grgur, M. Vojnović, and D. J. Šepa, Electroanal. Chem., 512, 27 (2001). 31. M. Miles, G. Kissel, P. Lu, and S. J. Srinivasan, J. Electrochem. Soc., 123, 332 (1976). 32. J. Wang, S. Mao, Z. Liu, Z. Wei, H. Wang, Y. Chen, and Y. Wang, ACS Appl. Mater. Interfaces, 9, 7139 (2017). 33. M. Gong, W. Zhou, M.-C.Tsai, J. Zhou, M. Guan, M.-C. Lin, B. Zhang, Y. Hu, D.-Y. Wang, and J. Yang, Nat. Commun., 5, 1 (2015). 34. E. C. Lovell, X. Lu, Q. Zhang, J. Scott, and R. Amal, Chem. Commun. (2020). 35. D. S. Hall, C. Bock, and B. R. MacDougall, J. Electrochem. Soc., 160, F235 (2013). 36. E. A. Franceschini, and G. I. Lacconi, Electrocatalysis, 9, 47 (2018). 37. H. Doan, I. Kendrick, R. Blanchard, Q. Jia, E. Knecht, A. Freeman, T. Jankins, M. K. Bates, and S. Mukerjee, J. Electrochem. Soc., 168, 084501 (2021). 38. M. Shen, N. Bennett, Y. Ding, and K. Scott, Int. J. Hydrogen Energy, 36, 14335 (2011). 39. H. Zhang, S. Su, G. Lin, and J. Chen, J. Int. J. Electrochem. Sci., 7, 4143 (2012). 40. H. Zhang, G. Lin, and J. Chen, Int. J. Hydrogen Energy, 35, 10851 (2010). 41. S. Mazloomi, and N. Sulaiman, Renewable Sustainable Energy Rev., 16, 4257 (2012). 42. M. M. Rashid, M. K. Al Mesfer, H. Naseem, and M. Danish, Int. J. Eng. Adv. Technol., 4, 2249 (2014). 43. M. Schalenbach, G. Tjarks, M. Carmo, W. Lueke, M. Mueller, D. J. Stolten, J. Electrochem. Soc., 163, F3197 (2016).

BEST OF THE BLOGS Which ECS blogs have been most popular since the last issue of Interface? Read on!

NEWS YOU NEED

Society members rely on the ECS blog to provide needed updates. The announcement that the 240th ECS Meeting was moving to a digital platform due to continued COVID-19 concerns opened the meeting up to members around the globe who wouldn’t have been able to attend the in-person meeting in Florida.

Top of the list of popular blogs was the ECS Publication Team’s announcement of a new focus issue on Women in Electrochemistry. Reducing gender inequality is the issue’s goal, with more than 50 women scientists from around the world guest editing this remarkable publication.

RESOURCES

From “Top 10 Science-Themed YouTube Channels” to “Top 15 Science and Technology Blogs,” ECS members turn to the blog for the resources they need to stay at the top of their game.

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An evergreen blog that people return to every winter is why batteries and cellphones go dead in cold weather. We all know not to rely on our car battery in the winter—but why? ECS blogs satisfy the curious.

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The best, brightest, and most exciting researchers in electrochemistry are affiliated with ECS. The blog keeps you up to date on whose star is in the ascendance. Top of the list of “Top 10 Battery Researchers to Watch” is long-time ECS member and board member Y. Shirley Meng.

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Check the ECS blog landing page and skim through recent posts to learn about everything from new grant and funding opportunities to a tribute focus issue celebrating John B. Goodenough’s 100th birthday, upcoming ECS meeting calls for abstracts, free ECS webinars with leading scientists, and more!

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Hydrogen is Essential for Industry and Transportation Decarbonization by Rod Borup, Ted Krause, Jack Brouwer

he latest report from the Intergovernmental Panel on Climate Change (IPCC) has confirmed what we already know: human activity is warming the globe due to emissions of carbon dioxide and other greenhouse gases.1 To meet emissions reductions targets, we must address all energy sectors simultaneously, including the electrical grid, transportation, and industrial processes. Hydrogen can be stored and transported within the existing natural gas system to provide lowcost massive storage capacity that (1) enables sustainable primary energy in all sectors of the economy; (2) has sufficient energy density for end-uses, including heavy-duty transport; (3) is a building block for zero-emissions fertilizers and chemicals; and (4) is sufficient to enable a 100% zero emissions grid.2 Solar and wind power conversion technologies have become cost effective recently, but challenges remain to manage electrical grid dynamics and to meet end-use requirements for energy-dense fuels and chemicals.2 Nuclear power is an additional option for zero CO2 electrical production, but it is typically used for base-load power. Hydrogen has unique features of separate power and energy scaling and a low self-discharge rate that enable the massive and seasonal energy storage that is required for a zero-emissions electric grid handling both daily and during the seasonal transients of a highly renewable electrical grid. The US transportation industry includes little renewable energy (estimated at 3.4%) and thus accounts for about 30% of all US greenhouse gas emissions.3 As the transportation sector seeks cleaner alternatives to combustion engines, hydrogen fuel cells promise a zero emissions and efficient alternative. In particular, the features of hydrogen are critical to enable zero emissions in any transportation application that requires (1) fast fueling, (2) long range, or (3) heavy payloads. Transitioning heavy-duty trucks to clean energy would cut about 20% of transportation-related greenhouse gas emissions in the US while eliminating even more criteria-pollutant emissions.4 Hydrogen is widely used in many industrial processes, including oil refining and ammonia production. To decarbonize the entire energy infrastructure, hydrogen use must be greatly expanded. Hydrogen can act as a zero-carbon energy carrier, coupling nuclear or fossil fuels with carbon capture, biofuels, and the renewable grid to decarbonize the entire energy infrastructure, including transportation, industrial processes, and energy storage supporting intermittent renewable power. Expanded use of hydrogen can decarbonize these important sectors of the economy. Renewable hydrogen is critical to decarbonize industrial processes that require high temperature heat (e.g., cement, glass), metal refining (e.g., steel), chemical feedstocks (e.g., oil hydrogenation, ammonia), and reducing gas (e.g., for computer chips). Hydrogen can be stored, distributed, and used as a fuel or feedstock in transportation, for stationary/back-up power, and in multiple industrial sectors. Fuel cell system provision of electrical power and heat within the industrial sector is also a large opportunity. Many industries generate electrical power onsite from process gases. For example, in the steel industry, hydrogen is being pursued to replace coke in blast furnace operations and natural gas use in direct reduced iron (DRI) processes. That is only part of the issue. Coke not only reduces iron ore and provides heat to drive the endothermic reactions, but the off-gas is also a relatively high BTU gas that is combusted to generate electric power for steel-making operations. Coke is responsible for about 40% of CO2 emissions in steel production but only about half of the CO2 emissions come directly from the blast furnace; the other half come from power plant

operations. If the steel industry were a country, it would rank third behind the US and ahead of India in terms of CO2 emissions. Steel is just one example, and there are similar situations in other industries. Commercialization advances are being made in the potential enduses for hydrogen that include: • • •

•

• • •

Many companies are investing heavily in the development and advancement of all major types of fuel cells, including use for transportation and stationary applications. Fuel cell forklifts are in widespread use throughout the world (hundreds of thousands of units are in operation worldwide) with hundreds of thousands of fueling events each year. Light-duty fuel cell vehicles are being commercially deployed in California, Europe, Japan, Korea, and China—where hydrogen fueling stations are commercially available and reliable. These are occurring with subsidies, but with a clear path toward profitability. Heavy-duty vehicles and busses are being advanced by many companies (e.g., General Motors, Toyota, Nikola, Hyzon, Hyundai, Ballard) and are being demonstrated all around the world. Stationary fuel cell systems are widely deployed in California today (more than 400 MW installed) as well as throughout the northeastern US, South Korea, and Japan; all of these are capable of future operation on renewable hydrogen. Stationary backup power systems, already operating on hydrogen, are being widely used in telecom and other applications throughout the US. Renewable H2 use in the ammonia, methanol, and steel industries is beginning to be commercialized. H2 is being blended with natural gas at small volumes with the blend used by conventional end users of natural gas to generate partially decarbonized power and heat and to begin the transition to a totally decarbonized gas system (e.g., the DOE-funded consortium HyBlendTM).

Hydrogen in the Transportation Sector Transportation is a key sector that hydrogen can play the major role in decarbonizing. Fuel cells provide the same zero tailpipe emissions benefits as battery power, plus they offer extended range, shorter refueling times, and heavier payload capabilities that are especially important for heavy trucks, trains, and airplanes. A major driving force for transportation fuel cells is the promise of zero-emissions: the only emission from a fuel cell is water. Regulators both in the US and worldwide are considering adopting clean-transportation standards that eliminate carbon emissions; legislation varies in terms of implementation time, but some appear as early as 2025. For example, California is requiring that 50% of trucks be zero-emissions by 2035 and 100% by 2045, and it plans a ban on sales of gasoline-powered cars in 2035.5 This type of legislation exemplifies the need for vehicle electrification by fuel cells (that is, use of renewable-powered water electrolysis to make the hydrogen fuel) with different features compared to renewable power charging of batteries. In addition, growing public desire and stakeholder/ shareholder demand are moving companies toward cleaner options as the public has become more aware of the impacts of climate change and air pollution. (continued on next page)

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While hydrogen fuel cells could one day power trucks, locomotives, planes, ships, and daily commutes, the transition from the combustion engine to fuel cell motors faces an infrastructure hurdle. Namely, the hydrogen fueling infrastructure hasn’t developed sufficiently to give fuel cell–powered cars a world in which they can reliably fill their tanks. Japan, with the most hydrogen filling stations, still has only ~160; Germany has ~90; and there are only ~50 (mostly in California) in the US. However, commercial semi-trailer trucks could be the catalyst. Most transit agencies in California are confirming the need for fuel cell electric buses for their longest routes and heaviest payloads (two of the three features that favor hydrogen use for zero emissions). Deployment of fuel cell trucks and busses can greatly speed the deployment of hydrogen infrastructure because they run on regular routes, simplifying the initial build-out of hydrogen fueling stations—picture a string of them along an interstate system, for starters. Those stations would make it easier for car drivers, as well, which would help develop the market in personal transportation. Also, a key issue when you move from trucks to trains, ships, and planes is the challenge of storing enough hydrogen onboard to meet the operation capabilities that petroleum currently provides. The low volumetric energy density of hydrogen is a challenge compared to fossil fuels, but, this could possibly be overcome with a combination of higher efficiency (requiring less fuel energy), and production of hydrogen–derivative energy carriers (e.g., ammonia, methanol). A hydrogen infrastructure is also needed that can produce and distribute the volume of hydrogen that is needed. This infrastructure includes distributed generation and pipelines for centralized and large scale hydrogen storage. This transition requires investment in corner hydrogen fueling stations (that can fuel many hundreds of vehicles/day) together with electrical system upgrades for battery electric vehicle charging to cost-effectively enable 100% zero-emissions transport in almost any jurisdiction in the world. For this reason, developing a dependable, long-lasting hydrogen fuel cell for trucks is the focus of a new US Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office (HFTO) within the Energy Efficiency and Renewable Energy Office (EERE) consortium called the Million Mile Fuel Cell Truck (M2FCT). M2FCT will focus on fuel cell durability, performance,

and cost to better position fuel cell trucks as a viable option in the long-haul trucking market.6 Although significant advances have been made and early commercial fuel cell light-duty vehicles (LDVs) are starting to be produced,7 fuel cells in the heavy-duty-vehicle (HDV) transportation sector (e.g., trucks, long-haul semi-trailers, maritime, trains) are nascent, despite the fact that the advantages of fuel cells compared to both diesel and electric powertrains are compelling in terms of emissions, charging time, efficiency, and power-toweight ratio, among others.8 Furthermore, HDVs are traditionally more polluting in terms of criteria pollutants and greenhouse gas emissions, and HDV applications are more regular in their drive cycle and routes, thereby alleviating the initial hydrogen infrastructure challenges.9 However, the fuel-cell technology for HDVs requires a paradigm shift in fuel-cell research and development compared to LDVs, where the emphasis becomes efficiency and 4- to 5-times improvements in durability instead of a focus on increased power densities and emphasis on lower cell costs. These emerging fuel-cell applications are summarized in Fig. 1, which depicts the importance and implications of the shift from LDV to HDV applications in terms of both size and daily mileage.4 Due to the much longer lifetime mileage of HDV vehicles, priority shifts from initial capital to operating costs. This shift moves the research and development emphasis away from a focus on low-platinumloaded electrodes and very high power densities to new materials that mitigate degradation and increase efficiency at fully rated power.

Hydrogen in the Industrial Sector Hydrogen to Produce Liquid Transportation Fuels

Zero emissions hydrogen can be chemically reacted with other elements (e.g., nitrogen, carbon, oxygen) to produce fuels that are liquid at ambient pressure and temperature conditions. When reacting with carbon, the key issue is producing low (zero) carbon fuels by using captured CO2 as the carbon source and hydrogen to produce liquid fuels. When renewable H2 is coupled with high-purity CO2 emitted from industrial sources such as in ethanol plants, these liquids can serve as a feedstock to make other chemicals, or a low-carbon energy carrier, or used directly as a fuel.10 Hydrogen can also be reacted with nitrogen to produce ammonia that can be used as both an energy carrier and fertilizer. A lot of focus has been on aviation fuels

Fig. 1. Roadmap to hydrogen fuel cells for transportation. Illustration of roadmap for transition from light-duty and automotive fuel cells to medium and heavyduty applications highlighting the paradigm shift in daily mileage and power output needs. The inset shows the trade-off between the operating and capitaldriven costs for three classes of vehicles.4 80

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since electrification of commercial aircraft by fuel cells or batteries is very challenging. Unlike the current industrial practice for producing liquid fuels that utilize fossil-derived syngas (CO + H2), utilizing captured CO2 waste streams and H2 produced by water electrolysis can significantly lower GHG and pollutant emissions from the use of the hydrogen-derived liquid fuels.

Methanol and DiMethyl Ether (DME)

There are two process approaches for converting CO2 and H2 to both methanol and DME: a one-step process that directly converts CO2 and H2 to methanol, and a two-step process that first converts CO2 to CO using the reverse water gas shift (RWGS) reaction and then hydrogenates CO with H2 to form methanol.11-12 Catalysts are typically CuZn-based supported on alumina, often with modifiers added. The direct CO2 methanol synthesis route tends to be more selective with fewer byproducts than the syn gas route due to the reaction being less exothermic and, because CO2 and H2 are fed to the reactor independently, one can control the CO2/H2 ratio to obtain the ideal ratio for optimal catalyst performance.13 A major disadvantage of the CO2 route is that there is a higher concentration of water in the reactor because of the higher concentration of CO2 which leads to decreased catalyst activity and lifetime as well as larger reactor sizes.14 Among the technical challenges are more active catalysts with better stability in the high-water environment generated in the CO2-to-methanol process that can operate at lower pressures and temperatures to favor higher methanol yields.

Electrochemical Ammonia Synthesis

Worldwide production of ammonia (NH3) was 235 million metric tons in 2019, making it the second highest produced commodity chemical.15 About 80% of the NH3 produced is used in fertilizer production, with the remaining 20% used in explosives, pharmaceuticals, refrigeration, and other industrial processes.16 There is growing interest in using NH3 as a carbon-free fuel for combustion applications or as a hydrogen-carrier for use with fuel cells due to its high volumetric energy density (15.3 MJ/L), its high hydrogen content (17.6 wt%), and the existing infrastructure for distribution, transport and storage.15,17 Industrially, NH3 is produced using the Haber-Bosch process.17,18 This process uses Fe-based catalysts that require temperatures of 300–500°C and pressures of 130–170 bar or Ru-based catalysts that operate at lower pressures (<100 bar). Conversion is low, about 10–15%, despite the harsh reaction conditions. The process is energy intensive, requiring over 30 GJ/metric ton of NH3, and has high greenhouse gas emissions of 2.16 kgCO2-eq/kg NH3 because of the high temperatures and pressures required and the use of natural gas or coal to produce the hydrogen feedstock.15 The latter accounts for more than 50% of total CO2 emissions. NH3 production consumes more than 1.4% of the world’s energy supply and emits more than 400 metric tons of CO2 annually.18 Replacing fossil-fuel derived hydrogen with clean (i.e., renewable, and/or zero emissions) hydrogen in the Haber-Bosch process can significantly reduce CO2 emissions in the ammonia industry. Using clean hydrogen to produce ammonia is not a new idea. Norwegian Norsk Hydro produced ammonia using hydrogen produced by alkaline electrolysis from the late 1920s into the 1990s. However, growing concerns over climate change have reignited the industry with plants producing “green” ammonia from electrolytic hydrogen currently operating in the UK and Japan with several demonstration and pilot plants announced in Australia, Europe, and the US.19 One of the most ambitious efforts is in Saudi Arabia, where 4 GW of renewable solar and wind energy will power electrolyzers producing enough hydrogen to produce 1,200 million metric tons of ammonia annually beginning in 2025. Although world-class ammonia plants can produce > 3,000 metric tons per day,18 there is growing interest in the ammonia industry in building small-scale modular plants that produce about one-tenth the amount of the larger plants to serve regional ammonia demands.20-21 Companies such as thyssenkrupp and Proton Ventures are developing small-scale “green” ammonia plants using these concepts. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Electrochemical routes are another potential option for producing “green” ammonia, with the potential to reduce energy consumption, simplify reactor design, and reduce overall process complexity and cost compared to the Haber-Bosch process. The electrochemical nitrogen reduction reaction (NRR) is a multiple proton-electron transfer reaction involving six protons and six electrons with the N2 reduction occurring at the cathode and water serving as the source of the protons generated by the hydrogen evolution reaction (HER). Designing catalysts that promote the NRR while limiting the HER has proved to be challenging.15,16,22-25 Developing NRR catalysts with NH3 production rates >104 mol h-1 cm-2, which is two orders of magnitude higher than current levels, is required to move the technology closer to commercial feasibility.

Hydrogen in Steel Manufacturing

The global steel industry produced nearly 1.9 billion metric tons of steel in 2020, generating over 3 billion metric tons (t) of CO2, amounting to 7–9% of the world’s CO2 emission.26-27 Current manufacturing practices produce 1.85 t of CO2 per t of steel produced. With demand for steel expected to reach 2.5 billion t per year by 2050, the steel industry will have to reduce its carbon intensity from 1.85 to 0.2 t of CO2 per t of steel to reach 2015 Paris Climate agreement goals. The reduction of iron ore, magnetite, and hematite to iron using the blast furnace–basic oxygen furnace process (BF-BOF) is the major source of CO2 emissions within the industry. More than 70% of the world’s steel is produced by the BF-BOF process where coke and coal dust serve as fuel and reducing agent, and create carbon as an alloying element.28 Hydrogen can serve both as a reducing agent and a fuel to reduce iron ore to iron, thus providing an option to significantly reduce CO2 emissions. The steel industry is currently developing processing technologies that can utilize hydrogen. Two options for using hydrogen are (1) as an auxiliary reducing agent in the BF-BOF process, and (2) as the sole reducing agent in the DRI process.29 The use of hydrogen in the BF-BOF process does present some challenges.26-29 The reduction of hematite by carbon monoxide, which is generated from coke and coal dust within the BF, is an exothermic process; whereas reduction with hydrogen is an endothermic process that requires additional hydrogen to be consumed to provide the energy needed to drive the reduction. Other challenges include injecting hydrogen into the BF through the tuyeres that are normally used to inject coal dust and coke, which provide stability to the flow of molten iron within the BF that using hydrogen alone cannot provide. Recently Germany steelmaker, thyssenkrupp Steel, became the first steel company to demonstrate the use of hydrogen in the BF process.30 An alternative to the BF-BOF process is the DRI process which uses a mixture of carbon monoxide and hydrogen generated by reforming natural gas or gasifying coal as the reducing agent.27,31 Unlike BF-BOF, DRI does not require that the iron be melted and therefore it can operate at a lower temperature. It was developed independently by Midrex and HYL-Engiron in the 1960s and currently accounts for about 5% of annual steel production.27 CO2 emissions by the DRI process are about 30–40% lower than the BF-BOF process. Companies such as Swedish steelmaker, SSAB,32 and Luxembourgish steelmaker, ArcelorMittal,33 are developing processes that will enable the DRI process to not only operate using only hydrogen, but also to produce CO2-free steel.

Hydrogen for Energy Storage and Grid Leveling Energy storage technology is critical if the US is to achieve more than 25%–50% penetration of renewable electrical energy, given the hourly, diurnal, and seasonal intermittency of wind and solar power. As the penetration increases, the need for both small-scale and largescale energy storage will increase dramatically. Seasonal storage of energy will require new methods for large-scale energy storage. (continued on next page) 81

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Hydrogen has features of separate power and energy scaling and low self-discharge that can enable the cost-effective, massive, and seasonal energy storage that is required for a zero-emissions electric grid and to introduce zero-emissions energy conversion into most sectors of the economy. This type of seasonal hydrogen storage can be expected to include mined salt caverns and porous rock formations. Lined rock caverns, bored wells, and buried vessels could provide alternatives in the absence of existing salt caverns, depleted oil and gas fields, or aquifers. Curtailment of electricity use is already occurring at the current renewable penetration throughout the US. Given their ability to cycle output within sub-seconds and start/stop within minutes, electrolyzers have the potential to help balance the intermittency of renewable power on the electric grid; turning on and ramping up when demand is high, and turning down or off when demand is low. These developments are incorporated into the new H2NEW consortium funded by DOE. Once produced, this hydrogen can be stored for long periods to adjust to seasonal consumption of energy, or converted back to electricity on a shorter-term basis (e.g., daily). The value proposition of hydrogen for enhancing resiliency of the electric grid while also supplying seasonal energy storage is summarized in Fig. 2 below. In choosing the methods by which we build a zero-carbon energy system, it is not enough simply to reduce greenhouse gas and pollutant emissions; we also must strive to maximize the societal co-benefits of this transition. As an example, a key energy service that is critically important to disadvantaged communities is providing backup power services during extreme weather events or other contingencies. Electrochemical technologies such as electrolyzers, fuel cells, and hydrogen storage can serve as critical buffers for these communities during outages. Underground delivery of renewable fuel will increase energy resiliency and reliability in all neighborhoods, especially those vulnerable to extreme weather events. Finally, the heavy-duty (e.g., trucking, trains, ships, aviation) and industrial sectors, which emit pollutants that primarily affect disadvantaged communities, can best be decarbonized and made zero emissions using renewable hydrogen and its derivatives. Hydrogen is important for transport, industry, and social equity!35

Acknowledgment RB acknowledges support from the Hydrogen and Fuel Cell Technologies Office (HFTO), Office of Energy Efficiency and Renewable Energy, US Department of Energy (DOE) through the Million Mile Fuel Cell Truck (M2FCT) consortia, technology managers G. Kleen and D. Papageorgopoulos and contract no. with Los Alamos National Laboratory 89233218CNA000001. TK acknowledges that the work conducted by Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, under contract DEAC0206CH11357. JB acknowledges support from the Hydrogen and Fuel Cell Technologies Office (HFTO), Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE) and Southern California Gas Company cost-share for contract DE-EE0009249 entitled “Solid Oxide Electrolysis Cells (SOEC) Integrated with Direct Reduced Iron (DRI) Plants for Producing Green Steel.” The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. © The Electrochemical Society. DOI: 10.1149/2.F18214IF

About the Authors Rod L. Borup, Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, NM, U.S. Education: BS, University of Iowa; PhD, University of Washington. Research Interests: PEM fuel cells including fuel cell component durability, water transport, electrode design and gas diffusion layer (GDL) materials; Microwatt, milliwatt and watt level hydrogen fuel cell systems; Fuel cells for heavy-duty power.

Fig. 2. Hydrogen can store energy at a gigawatt-hour scale. The capacity ratings of each of these technologies refers to their discharge power. The time scale (y-axis) represents the duration for which that power can be discharged. Alongside the y-axis categories, grid services are identified that require power discharge for the respective time durations. (Source: National Renewable Energy Laboratory)34 82

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Pubs + Patents: 150+ papers, 15 patents, h-index: 43, i10-index: 107. Awards: Research Award of the Energy Technology Division of the Electrochemical Society (2014), DOE Fuel Cell Technologies Office Annual Merit Award for Fuel Cells (2016), LANL Fellows prize for leadership (2020). Work with ECS: Member, Energy Technology Division Executive Committee, 2020 Fellow Website: https://www.lanl.gov/science-innovation/scienceprograms/applied-energy-programs/index.php https://orcid.org/0000-0001-7647-1624 Theodore (Ted) Krause, Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, U.S. Education: BS, Ursinus College; PhD, University of Delaware. Research Interests: Hydrogen production, catalysis, fuel reforming, reactor engineering, fuel cell powertrains and hydrogen infrastructure for heavy-duty transportation application. Pubs + Patents: 50+ papers, 3 patents, h-index: 19, i10-index: 30. Awards: Argonne National Laboratory Pacesetter Award (2016), Laboratory Director’s Award (2017), Argonne National Laboratory Board of Governors’ Outstanding Safety Leadership Award (2017). Website: https://www.anl.gov/cse/hydrogen-and-fuel-cell-materials https://orcid.org/0000-0002-3449-3072 Jack Brouwer, Advanced Power and Energy Program, UC Irvine, Irvine, CA, U.S. Education: BS, MS, UC Irvine; PhD, MIT. Research Interests: High temperature electrochemical energy system dynamics; Renewable energy systems development; Dynamic simulation and control; Energy system thermodynamics, design, and integration; Electrochemical conversion devics and systems; Hydrogen production, storage, and conversion systems; Electrochemical reactions with concurrent heat, mass, and momentum transfer. Pubs + Patents: 160+ papers, 8 book chapters, h-index: 48; i10index: 143. Awards: Most highly cited paper in Applied Energy (2020); Most Influential Persons in Orange County, Orange County Register (2016); Outstanding R&D Achievement, high temperature fuel cell tri-generation, US DOE, Energy Efficiency and Renewable Energy (2014). Website: www.apep.uci.edu https://orcid.org/0000-0001-9260-7579

References 1. IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. 2. A. Saeedmanesh, M. A. Mac Kinnon, and J. Brouwer, Curr. Opin. Electrochem., 12, 166 (2018). 3. International Energy Agency, Renewables 2O18 Analysis and Forecasts to 2O23 (2018). 4. D. A. Cullen, K.C. Neyerlin, R.K. Ahluwalia, R. Mukundan, K. L. More, R. L. Borup, A. Weber, D. Myers, and A. Kusoglu, Nat. Energy, 6, 462 (2021).

5. New York Times, New Rule in California Will Require ZeroEmissions Trucks, June 25, 2020 and New York Times, California Plans to Ban Sales of new Gas-Powered Cars in 15 Years September 23, 2020. 6. https://millionmilefuelcelltruck.org/ 7. S. Satyapal, U.S. Department of Energy Hydrogen and Fuel Cell Technology Overview, FC EXPO 2020, Tokyo, Japan, February 26, 2020. 8. G. Guandalini, 2018 International Conference of Electrical and Electronic Technologies for Automotive (2018). 9. S. C. Davis, S. E. Williams, and R. G. Boundy, Transportation Energy Data Book: Edition 36, (2017), and Fast Facts on Transportation Greenhouse Gas Emissions, (2017). 10. G. Zang, P. Sun, A. Elgowainy, and M. Wang, Environ. Sci. & Technol., 55, 5248 (2021). 11. S. Al-Saydeh and S. J. Zaidi, Carbon Dioxide Conversion to Methanol: Opportunities and Fundamental Challenges, In Carbon Dioxide Chemistry, Capture and Oil Recovery, Ed: I. Karamé, (2018). 12. P. Styring, G. Dosen, and I. Toser, Front. Energy Res., 28, 663331 (2021). 13. D. S. Marlin, E. Sarron, and Ó. Sigurbjörnsson, Front. Chem., 6, 446 (2018). 14. M. Bowker, ChemCatChem, 11, 4238 (2019). 15. S. Ghavam, M. Vahdati, I. A. G. Wilson, and P. Styring, Front. Energy Res., 9, 580808 (2021). 16. S. Giddey, S. P. S. Badwal, A. Kulkarni, Int. J. Hydrogen Energy, 38 14576 (2013). 17. Ammonfuel – an industrial view of ammonia as a marine fuel. 18. A. H. Tullo, C&EN, 99, (2019). 19. V. Pattabathula and J. Richardson, CEP, 69 (2016). 20. T. Brown, The capital intensity of small-scale ammonia plants, Ammonia Energy Association (2018). 21. Small-scale green ammonia plants open up new storage possibilities for wind and solar power. 22. R. Zhao, H. Xie, L. Chang, X. Zhang, X. Zhu, X. Tong, T. Wang, Y. Luo, P. Wei, Z. Wang, and X. Sun, EnergyChem, 1, 100011 (2019). 23. H. Xu, K. Ithisuphalap, Y. Li, S. Mukherjee, J. Lattimer, G. Soloveichik, and G. Wu, J. Nano Energy, 69, 104469 (2020). 24. Y. Yao, J. Wang, U. B. Shahid, M. Gu, H. Wang, H. Li and M. Shao, Electrochem. Energ. Rev., 3, 239 (2020). 25. R. Singh, B. A. Rohr, J. A. Schwalbe, M. Cargnello, K. Chan, T. F. Jaramillo, I. Chorkendorff, and J. K. Nørskov, ACS Catal., 7, 706 (2017). 26. L. Holappa, Metals, 10, 1 (2020). 27. M. Peplow, Chem. & Eng. News, 99, 22 (2021). 28. D. Spreitzer and J. Schenk, Steel Res. Int., 90, 1900108 (2019). 29. Hydrogen in steel production: what is happening in Europe – part one, Bellona Europa (2021). 30. Injection of hydrogen into blast furnace: thyssenkrupp Steel concludes first test phase successfully, thyssenkrupp Steel Europe AG (2021). 31. DRI Products & Applications. 32. The world’s first fossil-free steel ready for delivery, SSAB, (2021). 33. ArcelorMittal Europe to produce “green steel” starting in 2020, ArcelorMittal (2020). 34. Analysis Insights: Energy Storage - Possibilities for Expanding Electric Grid Flexibility. NREL (National Renewable Energy Laboratory). 2016 NREL/BR-6A20-64764. 35. B. Tarroja, I. Zenyuk, and J. Brouwer, Bridging Magazine Advanced Power and Energy Program, University of California, Irvine (2021).

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Getting Hydrogen to the Gigaton Scale by Bryan S. Pivovar, Mark F. Ruth, Akihiro Nakano, Hirohide Furutani, Christopher Hebling, Tom Smolinka

ue to its ability to perform clean, efficient processes, hydrogen has long been promoted as the energy carrier of the future, but recent activity and advances suggest a tipping point has been reached as hydrogen is now being recognized by much of the world for its unique capabilities to strongly support global efforts in achieving climate neutrality. The coming decades will require a massive increase in the amount of hydrogen used in the energy system as well as a transition from largely thermochemical to predominantly electrochemical processes involving hydrogen. Hydrogen has long been promoted as the fuel of the future, dating back to at least the 19th century. While perhaps premature cycles of hydrogen hype have occurred over the past several decades, recent developments suggest that hydrogen will be a key enabling element of a clean, sustainable global energy system that can limit global warming. For this to happen, hydrogen will need to globally approach the gigaton-scale on an annual basis. However, before hydrogen can fully achieve its potential, challenges that need to be addressed include achieving scale and further research and development (R&D) advances. The Hydrogen Council, according to their website, “a global CEOled initiative of leading companies with a united vision and longterm ambition: for hydrogen to foster the clean energy transition for a better, more resilient future,” consisting of more than 100 current members, has released multiple studies over the past few years.1 These studies have suggested that in 2050, hydrogen may account for 18% of final energy demand, 6 gigatons of annual CO2 abatement, $2.5 trillion in revenue, and the creation of 30 million jobs.2 This scenario represents hydrogen at the gigaton-scale. Other current activities along similar lines include major government strategies/programs (in the multi-billions of dollars) as well as business investment at the multi-billion dollar level annually. This scale of investment is unprecedented for hydrogen and these investments are being made based on the assumption of major hydrogen markets developing soon, but the extent to which hydrogen penetrates energy/industrial markets, the timeframe in which it occurs, and how the hydrogen is sourced remain dependent on a number of still undetermined factors. The way hydrogen is sourced, and the emissions associated with its production, have led to characterization of hydrogen by different “colors.”3 Historically natural gas derived (gray) hydrogen has dominated the market without concern for emissions. While green hydrogen is often touted as the ultimate goal, blue hydrogen offers an alternative pathway for emission-free hydrogen. Additional colors of hydrogen have also been proposed, including black (coal), turquoise (methane pyrolysis), yellow (nuclear), and golden (photoelectrochemical), but gray, blue, and green have been the dominant focus of the global community. Any “color” hydrogen offers benefits of hydrogen end use in terms of cleaner, more efficient processes and the establishment of a hydrogen infrastructure and supply chain. There are now several analysis studies highlighted in Fig. 1 that suggest hydrogen can and/or will achieve the gigaton scale and do so in an economically competitive manner.2,4,5 These analyses typically assume that both the economic advantages of achieving gigaton scale and R&D advances in cost, performance, and durability are achieved in hydrogen systems. While there is a reasonable basis to assume that these factors will occur, they are not a foregone conclusion and require significant investment. The factors of scale and R&D advances are expanded on in the following sections.

Getting to Gigaton Scale Achieving (gigaton) hydrogen scale remains a key challenge, as the economics of hydrogen are worse at smaller scale where costs on a per unit basis are higher due to increased per unit costs for the supporting infrastructure and supply chain. In fact, the central importance of achieving scale for hydrogen is reflected in the names of reports (the Hydrogen Council’s: Hydrogen: Scaling Up report, Gigaton H2 Workshop report) and national efforts (the US Department of Energy H2@Scale initiative, the European 2x 40GW electrolysis initiative). The ability to achieve scale would result in economic advances impacting the ability to make, store/move, and use hydrogen more cost competitively. Topical areas of concern for this to happen include infrastructure, supply chain, and policy considerations.

Infrastructure

Hydrogen, as a low energy density gas that requires extremely low temperatures to achieve and maintain liquefaction, has certain parallels to methane (natural gas). However, natural gas has a large, developed infrastructure around the world (multi-trillion dollar globally) to enable distribution and storage. In addition, natural gas can be extracted to meet the need in a timely manner (i.e., it is de facto stored) until desired for distribution. A similar hydrogen infrastructure is possible. In select locations, hydrogen pipelines and geologic storage (1600 miles of pipeline and 3 salt dome storage facilities in the US) have been demonstrated economical in support of petrochemical refining and ammonia production.6 Methane has three times the energy density of hydrogen on a volumetric basis, so significantly more hydrogen (on a volume basis) would need to be stored to match the energy equivalent of natural gas. But hydrogen also has a third the viscosity of natural gas, so it can move through an established gas pipeline infrastructure faster, helping offset some of these transmission costs. Select initial analysis of long-distance energy transmission suggest that hydrogen distribution may have as small as a 33% infrastructure cost penalty compared to natural gas, although much more effort is required in this area.7 Pipelines represent the lowest cost transmission option for hydrogen at scale, but are expensive to build out piecemeal, and other options such (continued on next page)

Fig. 1. Several existing reports estimate hydrogen demand nearing one gigaton annually.2,4,5 The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

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as liquefaction with trucking and shipping or conversion to liquid hydrogen carriers make sense at lower scale or for trans-oceanic distribution. For these reasons, currently the cost of moving and storing H2 is much more impactful than the cost of production and end-use. While scaling up today’s technology would have major impact, there also remain many areas where R&D can serve a critical role and these will be discussed in the next section.

Supply Chain

The supply chains across the hydrogen spectrum (making, storing/ moving, and using hydrogen) aren’t established today at the gigaton scale and therefore are unable to be leveraged effectively for the economical use of hydrogen. This supply chain development has connections to the infrastructure needs discussed above for the storing/moving aspects of hydrogen. For making and using hydrogen the supply chain is much less developed and at a smaller scale than other technologies (batteries, wind, solar), while also depending on a completely independent infrastructure for transmission. Building out the supply chain is independent, but it has clear parallels to the infrastructure challenges facing hydrogen.

Policy Considerations

While it isn’t the central focus of this piece, it is important to recognize that policy considerations are likely already impacting if and how hydrogen is being viewed, and that they will have significant impact on how fast hydrogen achieves gigaton scale. A select group of different policies, descriptions, and their potential impact on hydrogen are presented in Table 1. These policy considerations and perhaps others are likely to have a major impact on the timeframe and extent to which hydrogen gets to the gigaton scale.

R&D Needs/Challenges When considering the future of hydrogen, certain technological advances are typically assumed without a clear basis, and significant uncertainty exists, depending on the level of investment made. As already stated, the rate and extent to which these R&D advances are achieved will be critical to the timeline and scale at which hydrogen will be deployed. The co-authors of this piece have led an on-going Gigaton Hydrogen Workshop series to discuss these issues in an international context. Key areas of need and focus have been identified as make, move/store, use, and analysis and are briefly highlighted here; additional details are available in the full Workshop Report.8

Analysis

Hydrogen analysis is broad and crosscuts many different areas of interest. Several examples have been presented regarding exploring the economic and energy system impacts that hydrogen can have. Proper quantification of the business cases for hydrogen will be

critical for those looking to invest in hydrogen technologies. The impact of different drivers on the economics and the quantification of the potential benefits of hydrogen deployment will be important inputs for policy makers. Analysis will also be critical in system design and in appropriately focusing R&D priorities. Additional areas of analysis needed include higher fidelity energy system– wide models that can value the wide range of hydrogen attributes appropriately, transition analysis for an evolving energy system, and social science analysis that includes considerations for public acceptance. The needs for analysis in this space are very broad, and the complexity of hydrogen and how it impacts so many pieces and sectors of our evolving energy system make this area particularly challenging and exceptionally important.

Make

Hydrogen production is the critical first step for use in various processes and it can be accomplished by multiple routes. Reforming of hydrocarbons/fossil fuels is a well-established technology, but R&D and large-scale technical implementation around the world for CO2 sequestration remains an important issue for blue hydrogen. Other routes for hydrogen production include thermochemical and photochemical routes. These are at low technology readiness levels with significant challenges to achieve cost targets and remain active areas for R&D. Much of the focus in hydrogen production involves electrolysis where electricity is used to produce hydrogen by splitting water. Electrolytic water splitting is being investigated at low and high temperature through alkaline, proton exchange membrane (PEM), and solid oxide electrolysis. These technologies all have significant cost, performance, and durability concerns with active R&D. Specific challenges involve system integration with variable energy inputs, lower cost systems, and more durable and efficient operation.

Use

Hydrogen has potential applications in all energy sectors which include transportation, industry, buildings, and electricity. The wide range of potential uses for hydrogen provide a value proposition, but also add complexity to the most economical and beneficial ways to employ hydrogen. Significant focus has been placed on fuel cells with significant advances in the technology and commercialization of light-duty vehicles. The focus of hydrogen in transportation has shifted more recently toward medium and heavy-duty applications (and may increase in the area of stationary or combined heat and power for buildings), but many of the R&D challenges involving cost, performance, and durability remain. Fuel cells have a wellestablished R&D history, and the remaining needs are well articulated in multiple places. There is some overlap between fuel cells and electrolyzers in the types of systems, alkaline/alkaline membrane, PEM, and solid oxide being investigated for both applications. As these devices perform the same electrochemical half-reactions in forward and reverse, it isn’t a large surprise that there is significant overlap; however, the higher potentials required for electrolysis,

Table 1. Select Policy Considerations and Their Potential Impact on Hydrogen. Policy

Description

Impact on Hydrogen Economy

Renewable portfolio standards

Regulations at state and national level that require transitioning to higher levels of renewable energy generation (e.g., 100% renewables by 2050)

Increasing variable renewable energy creates large amounts of low-cost electricity that can drive low-cost hydrogen by electrolysis

Carbon costs

Taxing carbon dioxide emissions based on mass (e.g., $100/ton CO2)

Pushes for carbon-free technology and puts a premium on green and blue hydrogen

Internal Combustion Engine (ICE) mandates

Limiting sale or use of fossil fuel–based internal combustion engines (ICEs) in markets, taxing sales on ICE vehicles or fuels

Pushes electrified transportation, including hydrogen/fuel cells, into markets

Eased access to electricity markets

Access to wholesale market prices for hydrogen production by electrolysis, considerations for electricity transmission and distribution costs

Improves the economics of hydrogen production from grid assets by electrolysis

Hydrogen production

Direct subsidizing of hydrogen production costs (e.g., $1/kg)

Financial incentive to increase economic viability of hydrogen production

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differences in reactant phases and products, and changes in duty cycle create some specific unique challenges in areas of research needs and leave electrolysis systems at a lower state of technological understanding than the more highly studied fuel cell systems. The use of hydrogen in applications beyond transportation has been a more recent focus, where the value of hydrogen as an energy carrier or chemical feedstock enabling cleaner, more efficient processes in other sectors is seen as an enabling aspect. The industrial sector, where hydrogen may be used as a chemical reductant or to provide high-quality heat, is seen as a key need and first stage to bringing hydrogen to scale. R&D needs are significant to increase the economic viability of hydrogen in ammonia production, in the synthesis of synthetic fuels or chemicals, in the reduction of metals, as well as for use in other smaller markets. These areas tend to be focused on processes that can’t be easily electrified and often that work better continuously.

Store/Move

Hydrogen infrastructure is critical for connecting the entire hydrogen energy system and has significant R&D needs. The issue of infrastructure has many tradeoffs that depend on location; demand, including its temporal aspects; and production/delivery. Currently, these issues tend to be confined to solving the infrastructure problem for a single application in isolation, such as transportation, and building out individual solutions. It is important to increase the hydrogen infrastructure size to drive down cost and reliably meet demand. Select R&D needs that span different storing and moving considerations for hydrogen include compression (electrochemical and mechanical), liquefaction, storage systems (bulk hydrogen, geologic storage, surface storage), advanced pipelines (retrofitting existing infrastructure), and codes and standards development (protocols, safety, standardization).

Conclusion We are at a transformational time for hydrogen, as its use in our energy system changes from predominantly thermochemical toward electrochemical, and the scale at which it is used will increase by over an order of magnitude. It is clear that hydrogen’s role will grow in the future, but uncertainty remains around the extent, the manner, and the timeframe in which this transition will occur. Areas including infrastructure, supply chain, and policy will be critically important, but R&D advances remain the most uncertain and will likely be a major focus of government and industrial efforts in the coming decade.

Acknowledgment The authors acknowledge funding from the Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cells Technology Office under Contract numbers DE-AC3608GO28308 (NREL). The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. © The Electrochemical Society. DOI: 10.1149/2.F19214IF

About the Authors Bryan Pivovar, Senior Research Fellow and Electrochemical Engineering and Materials Chemistry Group Manager, Chemistry and Nanosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: PhD in chemical engineering (University of Minnesota). Research Interests: Fuel cells and electrolysis. Work Experience: Led fuel cell R&D at Los Alamos National Laboratory prior to joining NREL, where oversees NREL’s electrolysis and fuel cell and materials R&D. Recently named Director, U.S. Department of Energy consortium H2NEW (Hydrogen from Next-generation Electrolyzers of Water). Pubs + Patents: 150+ papers with 10,000+ citations. Awards: Tobias Young Investigator Award (2012) and Energy Technology Division Research Award (2021) from The Electrochemical Society. Work with ECS: Led efforts and organized workshops in subfreezing effects, alkaline membrane fuel cells (2006, 2011, 2016, and 2019), and renewable hydrogen at the gigaton scale (2019). https://orcid.org/0000-0001-5181-5363 Mark Ruth, Manager of the Industrial Systems and Fuels Group in the Strategic Energy Analysis Center at the National Renewable Energy Laboratory (NREL), Golden, CO, U.S. Education: BS in Chemical Engineering (University of Colorado). Research Interests: Improving energy use in the industrial and transportation sectors, Developing methods to value opportunities in the energy sector, Technical analyses of hydrogen and bioenergy systems. Work Experience: 28 years at NREL; Leads the multi-laboratory effort to analyze the technical and economic potential of the H2@ Scale concept and analyses of the economic potential to convert existing nuclear power plants to flex between electricity and hydrogen production. Website: www.nrel.gov/analysis https://orcid.org/0000-0002-1838-0617 Akihiro Nakano, Deputy Director, Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Japan Education: PhD in Engineering (University of Tsukuba). Research Interests: Hydrogen energy systems. Work Experience: 30 years of R&D work in renewable energy, spanning industry, national laboratories, and government programs in the US, Europe, and Japan, including implementing the iTHEUS project with the Institute for Energy Technology (IFE) in Norway, TohokuUniversity, Helmholtz-Zentrum Geesthacht in Germany, and the EMPA in Switzerland under the CONCERT-Japan program. Past positions also include the Energy and Environment Council for Science, Technology and Innovation Cabinet Office, Government of Japan (2018 to 2020). (continued on next page)

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Hirohide Furutani, Director, Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Japan Education: PhD (University of Tsukuba). Research Interests: Hydrogen energy. Work Experience: 30+ years of experience in the development of the renewable energy industry and R&D of renewable energy and hydrogen. Christopher Hebling, Head of Hydrogen Technologies, Fraunhofer ISE, Freiburg, Germany Education: PhD in Physics (University of Konstanz). Work Experience: Founded the Group “Micro Energy Technology” at Fraunhofer; Co-Director, “Division Energy Technologies and Systems,” Fraunhofer ISE; Honorary Professorship in Chemical Engineering (University of Cape Town); Germany Delegate, ExCo of the Hydrogen TCP for R&D on Hydrogen of International Energy Agency IEA; Board Member, National Organization Hydrogen and Fuel Cells NOW.

Tom Smolinka, Fraunholder ISE, Freiburg, Germany Education: PhD (University of Ulm). Research Interests: Hydrogen technologies, Membrane water electrolysis, Solar hydrogen production, Techno-economic analysis of power to gas systems. Work Experience: After managing Fraunholder’s Electrolysis team, established its group, “Alternative Hydrogen Production,” followed by building up the group, “Chemical Energy Storage”; Engaged in several national and international activities on water electrolysis; Teaching position, University of Freiburg’s Master’s program on Sustainable System Engineering.

References 1. 2. 3. 4. 5. 6. 7. 8.

www.hydrogencouncil.com The Hydrogen Council, Hydrogen, Scaling Up (2017). A. Kusoglu, ECS Interface, 30, 34 (2021). International Energy Agency, The Future of Hydrogen: Seizing today’s opportunities (2019). Shell, Shell Scenarios Sky Meeting the Goals of the Paris Agreement (2018). USDrive, Hydrogen Delivery Technical Team Roadmap (2017). J. R. Fekete, J. W. Sowards, and R. L. Amaro, Int. J. Hydrogen Energy, 40, 10547 (2015). H. Furutani, B. Pivovar, and C. Hebling, The 1st Gigaton Hydrogen Workshop Summary Report, AIST, NREL, Fraunhofer ISE (2020).

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SECTION NEWS

Introducing the ECS Mid-America Section The ECS Board of Directors approved the charter of the ECS Mid-America Section on October 22, 2021. The Society now hosts 23 region-specific sections providing opportunities for regional scientists and engineers to connect with researchers and participate in events. The ECS Mid-America Section includes members in Idaho, Illinois, Ohio, and Kentucky. Chartering the new section dissolves the inactive ECS Cleveland and Chicago Sections—an action supported by section members in an online vote held July 29 through August 12, 2021.

The newly invigorated section serves more members and expands opportunities within the region. Goals are to recharge and engage members in Illinois and Ohio; simplify the administrative tasks of separate group structures; increase opportunities for members in four states to participate in volunteer activities; become more flexible and inclusive; and grow the regional membership network. Current Chicago and Cleveland section members are being transitioned to members of the ECS Mid-America Section through the remainder of their membership terms.

The officers of the ECS Mid-America Section are: Chair Dr. Andrew J. Wilson University of Louisville

Vice Chair Dr. Vignesh Sundaresan University of Notre Dame

Vice Chair Dr. Joaquín Rodríguez-López University of Illinois at UrbanaChampaign

The four-state section has ambitious and engaging plans for the future. The Executive Committee seeks to promote extensive interaction and collaboration among researchers, and to increase student and researcher interest in, and involvement with, the electrochemical community. Mid-America Section membership costs $10.

ECS San Francisco Section 2021 Daniel Cubicciotti Student Award The ECS San Francisco Section hosted its 2021 Daniel Cubicciotti Student Award ceremony on July 13, 2021. The section executive officers and Ms. Jennifer Correa, representing the award’s sponsor, Structural Integrity Associates, Inc., participated in the ceremony. Mr. Iwnetim (Tim) Abate, working with Prof. William Chueh and Prof. Thomas Devereaux at Stanford University, received the award for his research on improving the energy capacity of batteries to meet the ever-growing global demand for energy storage. Honorable Mentions were awarded to two University of California, Berkeley graduates: Ms. Sarah Berlinger, working with Dr. Adam Weber of Lawrence Berkeley National Lab and Prof. Bryan McCloskey of UC Berkeley, for research on understanding multi-component interactions among catalyst particles, polymers, and solvents in fuelcell electrode precursor inks, and how these forces drive electrode microstructure formation; and Mr. Eric McShane, working with Prof. Bryan McCloskey of UC Berkeley, for his research on the kinetic, transport, and degradation phenomena underpinning lithiumion battery operation during fast charge. Mr. Abate, Ms. Berlinger, and Mr. McShane lectured on their outstanding research work and lives in graduate school, and discussed their dreams of pursuing futures in the field of electrochemistry. They are dedicated to their research on energy-related topics and plan to stay in this area for their future careers. We bet on seeing them and their splendid research in future issues of Interface. (continued on next page)

ECS San Francisco Section members gather for the 2021 Daniel Cubicciotti Student Award ceremony. Top row from left to right: section executive committee members F. Rohit Satish, Gao Liu, and Oana Leonte. Second row from left to right: Honorable Mention winners Sarah A. Berlinger and Eric McShane, and section executive committee member, Chen Fang. Third row from left to right: Cubicciotti Student Award recipient Iwnetim I. Abate, section executive committee member Gozde Barim, and Abate’s graduate advisor, Adam Weber. Bottom row from left to right: SF section executive committee member Thanh-Nhan Tran, Structural Integrity Associates, Inc. representative Jennifer Correa, and Loza Tadesse, co-founder with Iwnetim Abate of SciFro.

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SECTION NEWS (continued from previous page)

Specially worth mentioning are the awardees’ equally outstanding and diverse extracurricular activities during the pandemic. Ms. Berlinger perfected her baking skills during the quarantine and shared the delicious sweets with the needy. Mr. McShane taught science to prison inmates through a community college program. Mr. Abate works with SciFro, a foundation he co-established to assist young Africans create innovative medical and energy devices to solve local problems.

Invited Young Investigator Lecture Series The ECS San Francisco Section organized its inaugural Young Investigator Lecture Series on November 19, 2021. The COVID-19 pandemic impaired travel and in-person conferences, disproportionately impacting people in the scientific field. While there are many invited virtual lectures by top-tier scientists, opportunities are lacking for younger and fledgling graduate students and postdocs. The ECS San Francisco section Young Investigator Lecture Series is a virtual invited lecture series for outstanding senior graduate students and postdocs. The inaugural lecture had 10 speakers from California universities. The section’s IDEA Committee organizes the series. The speakers are selected by the Young Investigator Lecture Nomination and Selection Committee. The lecture series runs quarterly. We invite speakers to apply for the February 2022 lecture series. Please send your lecture title, abstract, and CV to the ECS San Francisco Section. To qualify, applicants must be graduate students who have finished their PhD qualification exam or postdoctoral training with term appointments. A California affiliation is not required. Awardees have outstanding and diverse extracurricular activities during the pandemic. Top: Sarah Berlinger bakes gourmet cakes for the needy; middle: Eric McShane teaches science to inmates; bottom: Iwnetim (Tim) Abate co-leads Frontiers in Science for Africa.

apter membership provides many benefits, including:

Section Leadership

ECS Sections introduce and support activities in electrochemistry and solid state science within specific regions. They are critical to the Society’s regional and global success, providing a local network for members to interact and engage around shared interests important to electrochemistry and solid state science and technology—and connection to a larger global network of scientific interaction and collaboration. Section Name Arizona Section

Section Chair Candace Kay Chan

Section Name Mexico Section

Section Chair Carlos E. Frontana-Vázquez

Brazil Section

Luis F. P. Dick

Mid-America Section

Andrew J. Wilson

Canada Section

Heather Andreas

National Capital Section

Eric D. Wachsman

Chile Section

Jose H. Zagal

New England Section

Sanjeev Mukerjee

China Section

Yongyao Xia

Pacific Northwest Section

Jie Xiao

Detroit Section

Kris Inman

Pittsburgh Section

Open

Europe Section

Philippe Marcus

San Francisco Section

Gao Liu

Georgia Section

Open

Singapore Section

Zichuan J. Xu

India Section

Sinthai A. Ilangovan

Taiwan Section

Hsisheng Teng

Israel Section

Daniel Mandler

Texas Section

Jeremy P. Meyers

Japan Section

Seiichi Mayazaki

Twin Cities Section

Open

Korea Section

Won-Sub Yoon

If you are interested in becoming a member, please contact the ECS Community Engagement Department at Mary.Hojlo@electrochem.org. 90

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AWARDS AWARDS PROGRAM

Awards, Fellowships, Grants ECS distinguishes outstanding technical achievements in electrochemistry and in solid state science and technology, and recognizes exceptional service to the Society through the Honors & Awards Program. Opportunities for recognition are offered in the following categories: ECS Society Awards, Division Awards, Section Awards, and Student Awards.

Highlights follow. Visit www.electrochem.org/awards for more information.

Society Awards Fellow of the Electrochemical Society was established in 1989 as the Society’s highest honor in recognition of advanced individual technological contributions in the field of electrochemistry and solid state science and technology, and active ECS membership. The award consists of a framed certificate and lapel pin. Materials due by February 1, 2022. The ECS Allen J. Bard Award was established in 2013 to recognize distinguished contributions to electrochemical science. The award consists of a plaque containing a glassy carbon medallion; US $7,500 prize; complimentary meeting registration for the award recipient and companion; dinner held in the recipient’s honor during the designated meeting: and Life Membership in the Society. Materials are due by April 15, 2022. The ECS Toyota Young Investigator Fellowship was established in 2015 in partnership with the Toyota Research Institute of North America to encourage young professionals and scholars to pursue research into batteries, fuel cells and hydrogen, and future sustainable technologies. The fellowship is awarded to a minimum of one candidate annually. Recipients must present at a Society biannual meeting and publish their research in a relevant ECS journal within 24 months of receiving the award. The fellowship consists of a restricted grant of no less than US $50,000 to conduct within one year the research outlined in their proposal, and a one-year complimentary ECS membership. Materials are due by January 31, 2022. The Gordon E. Moore Medal for Outstanding Achievement in Solid State Science and Technology Award was established in 1971 for distinguished contributions to the field of solid state science and technology. The award consists of a silver medal; plaque; US $7,500 prize; complimentary meeting registration for the award recipient and companion; dinner held in the recipient’s honor during the designated meeting; and Life Membership in the Society. Materials are due by April 15, 2022.

The Leadership Circle Awards were established in the fall of 2002 to honor and thank our partners in electrochemistry and solid state science. It is granted in the anniversary year that an institutional member reaches a milestone level. The award consists of a commemorative plaque, and recognition on the ECS website and Interface magazine. Nominations are not accepted.

Division Awards The Battery Division Early Career Award Sponsored by Neware Corporation was established in 2020 to encourage excellence among postdoctoral researchers in battery and fuel cell research with the primary purpose to recognize and support development of talent and future leaders in battery and fuel cell science and technology. The award consists of a framed scroll; US $2,000 prize; and complimentary meeting registration. Materials are due by March 15, 2022. The Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation was established in 2016 to encourage excellence among postdoctoral researchers in battery and fuel cell research. The award consists of a framed scroll; US $2,000 prize; and complimentary meeting registration. Two awards are granted each year. Materials are due by March 15, 2022. The Battery Division Research Award was established in 1958 to recognize excellence in battery and fuel cell research and to encourage publication in ECS outlets. The award recognizes outstanding contributions to the science of primary and secondary cells, batteries, and fuel cells. The award consists of a framed certificate and US $2,000 prize. Materials are due by March 15, 2022. The Battery Division Technology Award was established in 1993 to encourage the development of battery and fuel cell technology, and to recognize significant achievements in this area. This award defines the field of interest covered as “that area of electrochemical technology which deals with the design, fabrication, scale-up, performance, lifetime, operation, control, and application of devices (i.e., primary and secondary cells and batteries, and fuel cells) in which chemical energy can be converted into usable electrical energy by an electrochemical process.” The award consists of a scroll; US $2,000 prize; and ECS Battery Division membership for as long as the recipient maintains Society membership. Materials are due by March 15, 2022. (continued on next page)

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AWARDS PROGRAM (continued from previous page)

The Electrodeposition Division Early Career Investigator Award was established in 2015 to recognize an outstanding young researcher in the field of electrochemical deposition science and technology. The award consists of a framed certificate and US $1,000 prize. Materials are due by April 1, 2022. The Electrodeposition Division Research Award recognizes outstanding research contributions to the field of electrodeposition and encourages the publication of high-quality papers in the Journal of The Electrochemical Society. The award is based on recent outstanding achievement in, or contribution to, the field of electrodeposition and will be given to an author or co-author of a paper that appeared in JES or another ECS publication. The award consists of a framed certificate and US $2,000 prize. Materials are due by April 1, 2022. The Energy Technology Division Walter van Schalkwijk Award in Sustainable Energy Technology was established in 2021 to recognize and reward research scientists, academicians, and entrepreneurs who make innovative and transformative contributions to sustainable energy technologies (devices, materials, and/or processes). The award consists of a framed certificate and monetary prize equal to 1/25th of the endowment with a maximum of US $2,500. Materials are due by April 15, 2022. The Industrial Electrochemistry and Electrochemical Engineering Division New Electrochemical Technology (NET) Award was endowed by the Dow Chemical Company Foundation in 1997 to recognize significant advances in industrial electrochemistry and to promote high-quality applied electrochemical research and development. The award consists of a commemorative plaque. Materials are due by May 1, 2022. The Nanocarbons Division Robert C. Haddon Research Award recognizes individuals who have made outstanding contributions to the understanding and application of carbon materials. The award consists of a scroll; US $1,000 prize; and assistance up to a maximum of US $1,500 to facilitate attendance at the meeting where the award is presented. Materials are due by October 8, 2022. The Sensor Division Early Career Award was created in 2021 to recognize promising early career engineers’ and scientists’ research contributions to the field of sensors. The award consists of a framed scroll; US $500 prize; complimentary meeting registration; and ECS Sensor Division Business Luncheon ticket. Materials are due by March 1, 2022. The Sensor Division Outstanding Achievement Award was created in 1989 to recognize outstanding achievement in research and/or technical contributions to the field of sensors and to encourage work excellence in the field. The award consists of a framed certificate and a US $1,000 prize. Materials are due by March 1, 2022.

Section Awards The Canada Section Electrochemical Award was established in 1981 to recognize significant contributions to the advancement of electrochemistry in Canada. The award consists of a gold medal. Materials are due by December 31, 2021. 92

The Europe Section Alessandro Volta Medal was established in 1998 to recognize excellence in electrochemistry and solid state science and technology research. The award consists of a silver medal and US $2,000 prize. Materials are due by February 15, 2022. The San Francisco Section Award was established in 2021 to recognize excellence in the field of electrochemical science and technology and/or solid-state science and technology, and acknowledge service to The Electrochemical Society. The award consists of an engraved plaque and US $2000 prize. Materials are due by February 15, 2022.

Student Awards The Battery Division Student Research Award Sponsored by Mercedes-Benz Research & Development recognizes promising young engineers and scientists in the field of electrochemical power sources. The award encourages recipients to initiate or continue careers in the field. Eligible candidates must be enrolled in a college or university at the nomination deadline. The award consists of a framed certificate and US $1,000 prize. Materials are due by March 15, 2022. Biannual Meeting Travel Grants are awarded for each Society biannual meeting. Many ECS divisions and sections offer travel grants to undergraduates, graduate students, postdoctoral researchers, and young professionals and faculty presenting papers at ECS biannual meetings. The awards consist of a variety of financial support, ranging from complimentary meeting registration to luncheon/reception tickets, travel support, etc. Each division and section has its own application requirements. 241st ECS Meeting applications are accepted from December 3, 2021 to February 28, 2022. 242nd ECS Meeting applications are accepted from April 8, 2022 to June 27, 2022. The Canada Section Student Award was established in 1987 to recognize promising young engineers and scientists in the field of electrochemical power sources. The recognition encourages recipients to initiate or to continue careers in the field. The award consists of a framed certificate and US $1,500 prize. Materials are due by February 28, 2022. The Colin Garfield Fink Fellowship was first awarded in 1962. The fellowship assists a postdoctoral scientist/researcher during the months of June through September in the pursuit of work in a field of interest to the Society. The award consists of US $5,000 in funding and publication within the award year of a summary report in the winter issue of Interface. Materials are due by January 15, 2022. The ECS General Student Poster Session Awards were established in 1993 to acknowledge quality and thoroughness of the candidates’ work; originality and independence of their contributions; significance and timeliness of research results; and depth of understanding of the research topics and their relationship to the Society’s fields of interest. Three awards are given for each Society biannual meeting. The first place award consists of a US $1,500 cash prize; second place is a US $1,000 cash prize; third place is a US $500 cash prize. Awardees are also recognized with a certificate and announcement in Interface issues accompanying the respective The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

AWARDS AWARDS PROGRAM meeting’s Biannual Meeting Highlights article. To be considered, students must submit an abstract to the General Student Poster Session by the biannual meeting abstract deadline. The ECS Outstanding Student Chapter Award (formerly The Gwendolyn B. Wood Section Excellence Award) was established in 2012 to recognize distinguished student chapters that demonstrate active participation in The Electrochemical Society’s technical activities; establish community and outreach activities in the areas of electrochemical and solid state science and engineering education; and create and maintain a robust membership base. Up to three winners are selected, with one named the Outstanding Student Chapter, and up to two named Chapters of Excellence. The Outstanding Student Chapter award consists of a recognition plaque; US $1,000; and award recognition and chapter group photo in Interface or other electronic communications. Chapters of Excellence members receive mailed recognition certificates and acknowledgement in Interface. Materials are due by April 15, 2022. ECS Summer Fellowships were established in 1928 to assist students from June through August in the pursuit of work in a field of interest to ECS. The Society awards up to four summer fellowships each year, named as follows: Edward G. Weston Fellowship, Joseph W. Richards Fellowship, F. M. Becket Fellowship, and the H. H. Uhlig Fellowship. Each fellowship consists of US $5,000 in funding to support the recipient’s research. Publishing a summary report in the winter issue of Interface within a year of receiving the award is required. Materials are due by January 15, 2022.

The Pacific Northwest Section Electrochemistry Student Award Sponsored by Thermo Fisher Scientific was established in 2021 to recognize promising young engineers and scientists pursuing a PhD in the field of electrochemical engineering and applied electrochemistry. The award consists of a US $1,000 prize. Materials are due by February 28, 2022. The San Francisco Section Daniel Cubicciotti Student Award was established in 1994 to assist a deserving student in Northern California pursue a career in the physical sciences or engineering. The award consists of an etched metal plaque and US $2,000 prize. Up to two honorable mentions are extended, each to receive a framed certificate and US $500 prize. Materials are due by February 15, 2022. The Sensor Division Student Research Award was created in 2021 to recognize promising students in their graduate training for conducting outstanding research in the field of sensors. The award consists of a US $200 prize; framed scroll; complimentary meeting registration; and ECS Sensor Division Business Luncheon ticket. Materials are due by March 1, 2022.

SUPPORT THE NEXT GENERATION THROUGH STUDENT AWARDS! Student awards—part of the ECS Honors and Awards Program—support the next generation of scientists by expanding opportunities as they progress in their careers. These awards acknowledge student and early career scientists’ dedication and outstanding achievements in their fields of study.

Visit www.electrochem.org/student-awards to learn more. The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

NEW MEMBERS See who joined ECS in July, August, and September of 2021. (Members are listed alphabetically by family/last name.)

Members

Anis Allagui, Sharjah, Sharjah, United Arab Emirates

Subarna Banerjee, Greenville, SC, USA Sagnik Basuray, Livingston, NJ, USA Zineb Belarbi, Albany, OR, USA Eric Beyne, Leuven, Flemish Brabant, Belgium Klaus Brandt, Wiesbaden, Hesse, Germany Paul Braun, Urbana, IL, USA

Dany Carlier, Pessac, Nouvelle-Aquitaine, France Peter Caulfield, Downingtown, PA, USA Ji Chen, Boston, MA, USA Gregory Cooper, Columbia, MD, USA

Ting Du, Boston, MA, USA Nathan Dunlap, Golden, CO, USA

Paul Franzon, New Hill, NC, USA Viatcheslav Freger, Haifa, Israel

Xiang Gao, Charlotte, NC, USA

David Hakala, Brownsburg, IN, USA Haleigh Howe, Houston, TX, USA

Rameshwori Jalan, Bayreuth, Bavaria, Germany Krishna Jambunathan, Allentown, PA, USA Lu Jin, Berlin, Berlin, Germany

Pekka Laukkanen, Turku, Southwest Finland, Finland Young Hee Lee, Suwon, Gyeonggi-do, South Korea Hong Luo, Haidian District, Beijing, China

Rahul Manepalli, Chandler, AZ, USA Samuel McMaster, Chelmsford, Essex, UK Mateen Mirza, London, Middlesex, UK Stephane Moreau, Grenoble, AuvergneRhone-Alpes, France

Simon O’Kane, Bath, Somerset, UK

Quoc-Thai Pham, Taipei, Taipei, Taiwan

Seth Rogers, Amesbury, MA, USA

Meenu Sharma, Gandhinagar, GJ, India Brian Slawski, Burke, VA, USA Partima Solanki, New Delhi, DL, India Stephanie Sutedja, Austin, TX, USA

Satoru Takehara, Kosai, Shizuoka, Japan Junichi Tatami, Yokohama, Kanagawa, Japan Francesca Maria Toma, San Leandro, CA, USA

Alex Usenko, Kansas City, MO, USA

Venkata Vajrala, Toulouse, Midi-Pyrénées, France Mallory Vila, Port Jefferson, NY, USA

Vinicio Ynciarte, Charlotte, NC, USA

Michael Zhao, West Vancouver, BC, Canada Ivan Zyulkov, Brussels, Brussels, Belgium

Student Members

Alexis Acevedo, Garrochales, PR, USA Kelechi Agwu, Tuscaloosa, AL, USA Paul Akinyemi, Potsdam, NY, USA David Alexander, Pensacola, FL, USA Megha Anand, Kongens, Lyngby, Denmark Kamsy Anderson, Fayetteville, AR, USA Micah Armstrong, Champaign, IL, USA Kübra Ayan, Wageningen, Gelderland, Netherlands Gamaliel Azariah, Winnipeg, MB, Canada

Sanaz Banifarsi, Ulm, Baden-Württemberg, Germany Josiel Barrios Cossio, Lexington, KY, USA

Marc Berliner, Cambridge, MA, USA Vikram Bharti, Sangareddy, Telangana, India Sahana Bhattacharyya, New York, NY, USA Ray Bi, Vancouver, BC, Canada Sayandeep Biswas, Cambridge, MA, USA Vincent Briselli, Norfolk, MA, USA

Tatiana Cahue, Joliet, IL, USA Rangjian Cao, Philadelphia, PA, USA Yifan Cao, Calgary, AB, Canada Adam Caridi, Orland Park, IL, USA Navneet Chaudhary, New Delhi, DL, India Raylin Chen, Urbana, IL, USA John Corsten, Ottawa, ON, Canada Eduardo Corte Real, Porto Alegre, Rio Grande do Sul, Brazil Ignacio Cuevas, Uppsala, Uppland, Sweden

Hector De Santiago, Morgantown, WV, USA Lucy Decker, Philadelphia, PA, USA Laurent Delafontaine, Irvine, CA, USA Jay Deshmukh, Halifax, NS, Canada Tsanaya Dhofier, Jakarta Selatan, DKI, Indonesia Bhavish Dinakar, Cambridge, MA, USA Ahmad Diraki, Montréal, Québec, Canada Abigail Dudek, Homer Glen, IL, USA

Ko Ebina, Sendai, Miyagi, Japan

Hengameh Farahmandazad, Delft, ZuidHolland, Netherlands Max Feinauer, Ulm, Baden-Württemberg, Germany Evangelia Founta, Southampton, Hampshire, UK

Antonin Gajan, Paris, Île-de-France, France Xiaosi Gao, Ithaca, NY, USA Matthew Garayt, Port Moody, BC, Canada Artem Gavrilev, Morgantown, WV, USA Ryan Gentile, Manhattan, IL, USA Thomas George, Somerville, MA, USA Andreas Gigl, Vienna, Vienna, Austria Albina Glibo, Slavonski Brod, Croatia Perrin Godbold, Waynesboro, VA, USA Vishwas Goel, Ann Arbor, MI, USA Daniel Gribble, Lafayette, IN, USA Katelyn Groenhout, Charlotte, NC, USA Payal Gulati, New Delhi, DL, India

(continued on next page) 94

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NEW MEMBERS H

Amir Sina Hamedi, Provo, UT, USA Alar Heinsaar, Tartu, Tartumaa, Estonia Zoe Henderson, Manchester, England, UK Sana Heydarian, Athens, OH, USA Javad Hosseinpour, Golden, CO, USA Yewei Huang, Philadelphia, PA, USA

Corey Inman, Philadelphia, PA, USA Samuel Inman, Charlottesville, VA, USA Prathap Iyapazham Vaigunda Suba, Calgary, AB, Canada

Sathya Narayanan Jagadeesan, Newmarket, NH, USA Yikai Jia, Charlotte, NC, USA Yash Joshi, Ithaca, NY, USA

Anna Kapulwa, Kofu, Yamanashi, Japan Adam Karcz, Calgary, AB, Canada Chamikara Karunasena, Lexington, KY, USA Masaru Kato, Sendai, Miyagi, Japan Lee Kendall, Charlottesville, VA, USA Dukhan Kim, Ann Arbor, MI, USA Bernhard Klampfl, Vienna, Vienna, Austria Sachin Kochrekar, Turku, Southwest Finland, Finland Daiki Kono, Yonezawa, Yamagata, Japan Victor Kontopanos, Charlottesville, VA, USA Venkatesh Krishnamurthy, Pittsburgh, PA, USA Lynn Krushinski, Chapel Hill, NC, USA Lenin Wung Kum, Dayton, OH, USA Rahul Kumar, New Delhi, DL, India

Alejandra Lazaro, Santiago De Querétaro, Querétaro, Mexico Paul Le Floch, Cambridge, MA, USA Asaph Lee, Philadelphia, PA, USA Donghun Lee, West Lafayette, IN, USA Eric Lees, Vancouver, BC, Canada Yu Leng, Shanghai, Shanghai, China Yiliang Li, Cambridge, MA, USA Alexander Liu, Cambridge, MA, USA Wenmei Liu, Villigen, AG, Switzerland Jhi Loke, Waterloo, ON, Canada Ruoxin Lu, Cambridge, MA, USA Zhaoyuan Lyu, Pullman, WA, USA

Mohsen Mahmoudvand, Calgary, AB, Canada Behzad Malekpouri, Tuscaloosa, AL, USA Hammad Malik, Reno, NV, USA Christopher Mallia, Cambridge, MA, USA Brianna Markunas, Philadelphia, PA, USA

Nicholas Matteucci, Cambridge, MA, USA Ryusuke Mizuochi, Yokohama, Kanagawa, Japan Bapuji Mohapatra, Bangalore, KA, India Wouter Monnens, Leuven, Flemish Brabant, Belgium Sascha Morlock, Wildau, Brandenburg, Germany Genevieve Moss, Plumstead, Western Cape, South Africa Adeel Muhammad, Venezia, Veneto, Italy Eamonn Murphy, Irvine, CA, USA

Arina Nadeina, Amiens, Hauts-de-France, France Ayumu Nagaoka, Yonezawa, Yamagata, Japan Dustin Nguyen, Boise, ID, USA Huy Nguyen, Chicago, IL, USA

Ugochukwu Odagwe, Lexington, KY, USA Emmanuel Ohiomoba, Lexington, KY, USA Greatness Olaitan, Charlottesville, VA, USA Alexander Olivelli, Lexington, KY, USA

Anand Pandey, Prayagraj, UP, India Habin Park, Atlanta, GA, USA Rohan Paste, Nangang, Taipei, Taiwan Vinay Patel, Hamilton, ON, Canada Hannah Patenaude, Las Vegas, NV, USA Gopinath Perumal, Gautam Buddha Nagar, UP, India

Alexander Quinn, Cambridge, MA, USA

Ashish Raj, Louvain-la-Neuve, Walloon Brabant, Belgium Philip Rapp, Munich, Bavaria, Germany Salvio Reza, Jakarta, DKI, Indonesia Katelyn Ripley, East Boston, MA, USA Venkataramana Rishikesan, Leuven, Leuven, Belgium Kevin Rivera Cruz, Ann Arbor, MI, USA Jaqueline Rojas, Cicero, IL, USA Arthur Ronne, Port Jefferson Station, NY, USA Julian Rosas, Toronto, ON, Canada Andrew Russ, Cary, IL, USA Dewan Russel Rahman, Stillwater, OK, USA Sabiha Rustam, Seattle, WA, USA

Reena Sajwan, New Delhi, DL, India Karthik Sarigamala, Mumbai, MH, India Petros Selinis, Xanthi, East Macedonia and Thrace, Greece Hatef Shahmohamadi, Calgary, AB, Canada

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Caitlin Shanahan, Orland Park, IL, USA Roshni Sharma, New Delhi, DL, India Sara Sheffels, Cambridge, MA, USA Armando Shehi, Charlottesville, VA, USA Shumpei Shimizu, Yamagata, Tohoku, Japan Abinaya Sivakumaran, Calgary, AB, Canada Alexander Smith, Stockholm, Södermanland, Sweden Samuel Snowden, Brighton, East Sussex, UK Taylor Soucy, Ypsilanti, MI, USA Michael Stadt, Lembach, Oberösterreich, Austria Vishnu Surendran, Wayanad, KL, India Midori Suzuki, Yonezawa, Yamagata, Japan

Kai-Jher Tan, Cambridge, MA, USA Ben Tang, Halifax, NS, Canada Amit Tanwar, Cork, Ireland Junhan Tao, Philadelphia, PA, USA Delvina Tarimo, Pretoria, Gauteng, South Africa Neha Tewari, Hong Kong, Sai Kung, Hong Kong Jiashen Tian, Tempe, AZ, USA

Atsuhiko Ueno, Yonezawa, Yamagata, Japan

Damini Verma, Delhi, DL, India Niraj Ashutosh Vidwans, College Station, TX, USA

Solomon Wakolo, Kofu, Yamanashi, Japan Guanyi Wang, Kalamazoo, MI, USA Trent Weiss, Ambler, PA, USA William Woltmann, Cambridge, MA, USA

Rong Xia, Newark, DE, USA Xinyi Xia, Gainesville, FL, USA Minghan Xian, Gainesville, FL, USA

Amit Yadav, New Delhi, DL, India Ren Yamazaki, Sendai, Miyagi, Japan Jiyoung Yoon, Aschheim, Bavaria, Germany Hiroki Yoshida, Sendai, Miyagi, Japan Melak Yosseif, Winnipeg, MB, Canada Jacky Tsz Tat Yu, Los Angeles, CA, USA Svena Yu, Vancouver, BC, Canada Chunhao Yuan, Charlotte, NC, USA

Zahid Ali Zafar, Prague, Prague, Czech Republic Lijie Zhang, Yokohama, Kanagawa, Japan Yifan Zhang, Atlanta, GA, USA Rui Zhao, Wuhan, Hubei, China Eniko Zsoldos, Redwood City, CA, USA

NEW MEMBERS New Members by Country

Look who joined ECS in the Third Quarter of 2021.

Belgium

India

Canada

Israel

China

Japan

Finland

South Korea

France

Taiwan

Germany

UK USA

Belgium........................2 Canada..........................1 China............................1 Finland..........................1 France...........................3 Germany.......................3 India..............................3 Israel.............................1 Japan............................2 South Korea..................1 Taiwan...........................1 UK.................................4 USA............................22

ECS MEMBERSHIP Inspiration, collaboration, and great benefits: ECS membership builds better electrochemists! www.electrochem.org/join

JOIN NOW!

Contact Anna.Olsen@electrochem.org to learn more about institutional membership benefits.

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STUDENT NEWS

2021 ECS Outstanding Student Chapter & Chapters of Excellence ECS congratulates the 2021 Outstanding Student Chapter winner, the ECS Clarkson University Student Chapter, for their dedication and commitment to the advancement of electrochemical and solid state science and engineering education. The Outstanding Student Chapter Award was established in 2012 to recognize distinguished ECS Student Chapters that demonstrate active participation in the Society’s technical activities; establish community and outreach activities in the areas of electrochemical and solid state science and engineering education; and create and maintain a robust membership base. The ECS Clarkson University Student Chapter has become one of the Society’s most exemplary chapters. In appreciation of their hard work, the chapter receives an additional $1,000 in funding; a recognition plaque; and acknowledgement in the winter issue of Interface. ECS is very proud of the ECS Clarkson University Student Chapter. Congratulations again! ECS also congratulates the two 2021 Chapter of Excellence winners, ECS University of Waterloo Student Chapter and ECS Purdue University Student Chapter. They receive certificates in addition to recognition in Interface for their stellar achievements in showcasing their commitment to ECS’s mission. Congratulations to both winners for their hard work and diligence! A special thank you to the Outstanding Student Chapter Award Subcommittee for reviewing applications and determining award recipients: William Mustain, University of South Carolina Neal Golovin, Booz Allen Hamilton Alice Suroviec, Berry College Interested in submitting your chapter’s achievements for consideration as the 2022 ECS Outstanding Student Chapter?

APPLICATIONS ARE DUE ON APRIL 15, 2022.

Student Chapter News ECS City College of New York Student Chapter The ECS City College of New York (CCNY) Student Chapter hosted an industry panel and networking session on September 8, 2022. The event attracted students from around the New York area, including students from CCNY and Columbia University. Peaking at 27 participants, the participants learned about pursuing careers in electrochemistry from Dr. Gautam Yadav, Dr. Alasdair Brown, and Dr. Stafford Sheehan. The three speakers provided great insights into targeting a resume for a job; discussion points for interviews; why they chose to pursue electrochemistry (and their startup companies); and more! Following the panel discussion and Q&A session, the speakers stayed on, allowing for smaller group networking sessions in Zoom breakout rooms. The student chapter greatly appreciated the time and advice given by the speakers!

Screen capture of the ECS City College of New York (CCNY) Student Chapter industry panel followed by networking in Zoom breakout rooms. Photo: Andrew May.

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

STUDENT NEWS ECS Clarkson University Student Chapter In July 2021, the ECS Clarkson University Student Chapter demonstrated lab experiments related to water quality testing to high school students in a two-day workshop, part of the chapter’s regular community volunteer work. Undergraduate and graduate students presented their research projects at the July 29 Clarkson University (CU) Summer 2021 Research and Project Showcase (RAPS). To encourage research in electrochemistry and to motivate students to participate, the Clarkson Student Chapter offered Best Presentation Awards in undergraduate and graduate poster and oral sessions. The chapter also presented an award for the most sustainable research project. At the university Fall Activities Fair on August 31, 2021, the chapter showcased its activities and promoted ECS to students.

The goal was to contact newly admitted students and recruit new members interested in ECS. Member benefits—including wonderful networking opportunities and career prospects through the member network—were presented. The CU-ECS lecture series, organized by the chapter, hosted Dr. Joshua Gallaway from Northeastern University in a joint seminar with the Chemical and Biomolecular Engineering Departments. A general discussion session with chapter members followed the event. Around 50 students and faculty members from the Chemical Engineering and Chemistry Departments enthusiastically participated in the seminar.

ECS Clarkson University Student Chapter members introduce ECS and the chapter to students at the Fall Activities Fair.

The ECS Clarkson University Student Chapter facilitated—and promoted through this flyer—Dr. Joshua Gallaway’s seminar talk for the Clarkson University Chemical and Biomolecular Engineering Departments.

A screenshot of Dr. Joshua Gallaway’s virtual presentation to the Clarkson University Chemical and Biomolecular Engineering Departments.

Attendees join a general discussion session following Dr. Joshua Gallaway’s joint-seminar presentation. 98

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

STUDENT NEWS ECS University of Virginia Student Chapter The ECS University of Virginia (UVA) Student Chapter held its first in-person event since the COVID-19 shutdown on September 22, 2021. The meeting and new leadership team revitalized the chapter and brought together students from different school years and departments, including Materials Science & Engineering and Chemistry. Students received a program overview while enjoying coffee and each other’s company. The chapter also discussed ideas for future events and different activities of interest to members. One of these events was held on October 13, 2021, when an inperson group watched the recorded 240th ECS Meeting keynote lecture, “Metal Electrodeposition across a Nanometre-Scale Gap,” presented by N. Missault and W. Schwarzacher from the University of Bristol. The event host asked all the event participants to register online for the 240th ECS Meeting. After viewing the recorded lecture, chapter members discussed the content and style of the presentation. Chapter members who presented virtually in the 240th ECS Meeting, including Carolina Moraes and Rebecca Marshall, shared the interactions that took place during their live symposium sessions.

Students attend this year’s second in-person event hosted by the ECS University of Virginia Student Chapter.

ECS University of Waterloo Student Chapter The ECS University of Waterloo Student Chapter (WatECS) worked hard over the past months to continue their mission to promote electrochemical and solid state science and technology. WatECS organized two virtual workshops during the summer. A COMSOL engineer introduced students to COMSOL’s electrochemistry module, demonstrating how to use the software to model electrochemical systems such as electroplating in the June 17 workshop on COMSOL Multiphysics for Electrochemistry. On July 15, the chapter cohosted a workshop with the Waterloo Commercialization Office (WatCo) on Intellectual Property (IP) and Commercialization 101.

Eric Luvisotto, WatCo Technology Transfer Manager and registered Canadian Patent Agent, and Michael Crinson, partner at Aitken Klee LLP and one of Canada’s most experienced intellectual property law trial counsels, discussed different types of IP protection and common pitfalls to avoid, as well as resources available at the University of Waterloo. The student chapter planned and hosted a virtual workshop series in November 2021 on electrochemistry techniques, including methods such as cyclic voltammetry and electrochemical impedance spectroscopy. Learn more about WatECS events on the chapter website.

Flyers promoting the ECS University of Waterloo Student Chapter COMSOL workshop and IP and Commercialization workshop.

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Send your student chapter news and high resolution photographs to education@electrochem.org www.electrochem.org/student-center

The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

STUDENT NEWS

ECS Welcomes Four New Student Chapters in October 2021 • Austria Student Chapter (Austria) • Harvard University (US)

• Jawaharlal Nehru University (India) • Massachusetts Institute of Technology (US)

ECS Student Chapter membership provides many benefits, including: • Engaging with students and peers; • Organizing technical meeting programs and scholarly activities; • Collaborating with members to present posters at ECS bi-annual meetings; • Networking with 8,000+ international ECS members; • Accessing career resources;

• Adding impressive extracurricular activities to resumes; • Funding to support chapter activities; • Partnering with local ECS sections on activities and technical programs; • Receiving recognition on the ECS website and in ECS’s quarterly publication, Interface.

Visit the ECS Student Center for more information about student chapters. To gauge the scope of the Society’s global student chapter network, check out the Student Chapter Directory. Interested in establishing an ECS student chapter at your academic institution? Read the guidelines for starting a chapter and fill out a new student chapter application today.

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The Electrochemical Society Interface • Winter 2021 • www.electrochem.org

Thank you! Benefactor

2021 ECS Institutional Members

research

Patron Energizer (76)

Lawrence Berkeley National Laboratory (17)

Faraday Technology, Inc. (15)

Scribner Associates, Inc. (25)

GE Global Research Center (69)

Toyota Research Institute of North America (13)

Sponsoring BASi (6)

Medtronic Inc. (41)

Central Electrochemical Research Institute (28)

Nissan Motor Co., Ltd. (14)

DLR-Institut für Vernetzte Energiesysteme e.V. (13)

Pacific Northwest National Laboratory (PNNL) (2)

EL-CELL GmbH (7)

Panasonic Corporation (26)

Electrosynthesis Company, Inc. (25)

Permascand AB (18)

Ford Motor Corporation (7)

Teledyne Energy Systems, Inc. (22)

GS Yuasa International Ltd. (41)

Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) (17)

Honda R&D Co., Ltd. (14)

Sustaining Cummins, Inc (3)

Occidental Chemical Corporation (79)

General Motors Holdings LLC (69)

Sandia National Laboratories (45)

Giner, Inc./GES (35)

Technic, Inc. (25)

Ion Power Inc. (7)

Western Digital GK (7)

Kanto Chemical Co., Inc. (9)

Westlake (26)

Los Alamos National Laboratory (13)

Yeager Center for Electrochemical Sciences (23)

Microsoft Corporation (4)

Please help us continue the vital work of ECS by joining as an institutional member today. Contact Anna.Olsen@electrochem.org for more information.

9/1/2021

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ECS is dedicated to moving science forward by empowering researchers globally to leave their mark on science. The Society connects a diverse and representative constituency of members and non-members to accelerate scientific discovery, facilitate the engagement of an inclusive network, and champion the dissemination of research to support a sustainable future.

For more information on becoming a member or publishing in ECS publications, visit electrochem.org