POWERING OUR FUTURE

Developing better batteries and alternative power sources is crucial for the future. Cutting-edge research and innovation at Southampton is helping to ensure we get there.

The need for better batteries is clear. Fossil fuels are limited in their supply and are damaging our world. Energy from renewable sources such as the sun and wind is only available when the sun shines and the wind blows. And current batteries are expensive, don’t last long enough, and are heavy and bulky.

Pioneering research by the Electrochemistry Group is changing this fast – the batteries of the future are within our grasp. There are several strands of ongoing research into different types of batteries and alternative power sources, including hydrogen and thermo-electrics.

Andrea Russell, Professor of Physical Electrochemistry, outlined: “We’re working on electricity production and use, taking carbon out of the electricity cycle. If we want to tackle climate change, we can either take the CO2 out of the atmosphere, or we can stop putting it out there in the first place. We are working on that second option.”

THE HYDROGEN ECONOMY

We currently live in the Carbon Economy. We burn fuels and produce CO2, and we’re living in a carbon cycle. Andrea’s research addresses how we can transition towards a Hydrogen Economy.

“We want to move away from carbon,” she said. “The ultimate fuel is hydrogen and the ultimate source of that would be water, if you can take the hydrogen out of the water using renewables. There is no carbon in the cycle, which is the game changer.”

Hydrogen fuel cells are already used in places such as London buses (pictured right). The only emission is water. But electrolysis – the process of extracting hydrogen from water – remains expensive, plus hydrogen is highly flammable and volatile so needs to be handled and transported with specific precautions.

Andrea is working on a project with Johnson Matthey, a sustainable technologies company, to better understand water electrolysers – specifically looking at the oxygen electrode.

“We’re trying to find better materials for the oxygen electrode for the water electrolyser,” she explained. “The most active material we know of is ruthenium oxide, but it’s not very stable. We’re trying to understand the degradation of the materials because then we can figure out how to use less of it, or make it run for longer.”

With further advances in research, Andrea predicts hydrogen will be used to power more vehicles: “Hydrogen will be used for bigger vehicles like lorries and aeroplanes, while batteries will be used for smaller transportation like cars.”

THERMOELECTRIC OPPORTUNITIES

Thermoelectricity draws heat from two things and turns that into electricity. It is used in niche areas, but for it to become widespread it needs to be more efficient.

Dr Iris Nandhakumar, Associate Professor in Electrochemistry, is an expert in the area. She said: “There are a lot of industrial processes that generate vast amounts of waste heat into the atmosphere, and cars generate a lot of heat from exhausts. If there were a technology that could turn that waste energy into energy that can be used, that would be invaluable.”

An up-and-coming area for thermoelectrics is variable energy harvesting. Iris sees huge potential in this when it comes to wearable technology.

“A thermoelectric watch would be one example, with an embedded thermoelectric harvester that converts body heat into electricity to power and charge the watch,” she said. “Thermoelectrics could also be used in sensors for healthcare technology. Having something you can wear on your body that charges itself from your body temperature is very much at the heart of the research I am doing.”

But a challenge to overcome is in the materials, which Iris is investigating.

She explained: “To enable wearable thermoelectric technology, we have to make thermoelectric materials that are flexible and follow the curvature of the body. Most thermoelectric materials are very brittle, so we have to find new sustainable materials, or embed these brittle materials in polymers that are flexible.”

BATTERY POWERED

We all use lithium batteries. They power our portable electronic devices and they are superior to other batteries in their lifespan. Lithium is a precious metal that is mined predominantly in South America and Australia – but it’s a finite resource that will run out if we don’t recover and recycle it.

Dr Nuria Garcia-Araez, Associate Professor of Electrochemistry, is working on a two-pronged attack on the issue – both recycling lithium, and using a different type of lithium.

Explaining her patented method for recycling lithium, Nuria said: “The battery material is in a structure with very small holes. These tiny holes only allow lithium ions to enter, as they are very small. Other ions such as sodium or potassium are too big. This means we can extract the lithium and use it again, and use the battery again, so the whole thing is circular.”

A second project is looking to develop a battery using lithium from Cornwall.

“There are not many places in the world where you can find lithium, so it’s great to have a source in the UK,” said Nuria, “but it’s a different type of lithium.” She is working with Cornish Lithium to develop new technology that will enable lithium from our shores to be used in batteries.

Andrew Hector, Professor of Inorganic Chemistry, is also addressing the lithium conundrum. He is looking at alternatives to lithium for negative electrodes in batteries, namely sodium and magnesium.

“Sodium batteries are cheaper than lithium and can be transported more safely, and magnesium batteries can have significantly higher capacities,” he said. “There are plenty of other advantages too – sodium is the sixth most common element on Earth, and magnesium is the eighth, so they are much more abundant than lithium.”

Whilst sodium works well in batteries, magnesium does not yet – but this is set to change through research such as Andrew’s.