'Storage is critical for meeting future energy needs,' says DPhil student Isaac Capone, current recipient of the Modentech scholarship in Materials Science. For three months, Isaac has belonged to the renowned Mauro Pasta and Peter Bruce Research Group, working to develop innovative materials for sodium-ion batteries with higher specific capacities and cycle life. These materials, he explains, will hold the key to developing new devices for portable and grid-scale energy storage, independent of the price of lithium.
Pioneered in Oxford in the 1980s, lithium-ion batteries revolutionised portable electronics, providing power for everything from laptops and mobile phones to household appliances. But with questions now being asked about the global supply of lithium, the need for a battery based on alternative materials has become a key challenge. To find a solution, research has turned towards other alkali metals – among which, sodium has been the most extensively studied.
This group is one of the best groups for their research on batteries – it’s brilliant that I can be here, absolutely brilliant.Isaac Capone
Isaac, who originates from Taranto, Italy, is working to develop new anodic materials for sodium batteries. 'Normally in lithium batteries we use graphite as an anode, but it doesn't work at all with sodium batteries,' he explains. 'We need to completely change the material.' He conducts his research alongside two colleagues specialising in cathodic and electrolyic materials, also for sodium batteries. 'When one of us finds something useful, we can bring all of our components together to see if the resulting cell works,' he explains. 'It will be a new battery.'
Sodium undoubtedly poses an attractive alternative to the conventional lithium battery. While lithium is relatively rare, with reserves mainly located in South America, sodium 'can be found everywhere. If you pick up a stone outside, or even take a sample of seawater, you can find sodium,' says Isaac. As Earth's seventh most abundant material, it has the potential to reduce battery production costs considerably. 'Price moves economy,' he notes.
Discovering a more efficient energy storage system is vital to reducing our dependence on fossil fuels, making sodium-ion batteries especially attractive for applications on the electricity grid. Renewables often produce power intermittently, and currently require coupling with a storage system, such as a dam, to ensure that the supply of electricity can be reliably maintained. If solar or wind power could be economically stored, and then released on command, it would fundamentally change the way the world provides and consumes power.
The market for new battery technologies is expected to rise significantly in the coming years. Costly lithium-ion technology, for example, is one of the main barriers to widespread uptake of electric vehicles. 'A person that's going to buy a car cares about the cost,' says Isaac. 'It's very different to spend £40,000 on a car than it is to spend £10,000.' Home storage units for the energy generated from solar panels will be increasingly sought after too.
With a normal lithium battery you can do up to 2,000 cycles charging and discharging. With sodium we want to achieve at least the same performance level, if not better.Isaac Capone
Isaac estimates that research into sodium batteries could take up to 10 years to complete. 'Most of the work taking place now is focused on improving lithium batteries, because we know they work,' he says. 'But we are reaching a plateau now. We really do need to find an alternative,' he adds.
Isaac is studying in Oxford on a three-year scholarship, which has been generously supported by Modentech.