Devices               Batteries               Electrocatalysis               Material Design

We work across the LiSTAR (Lithium-Sulfur Technology Accelerator) project of Faraday Institution, UK’s flagship battery research programme aiming to place the UK at the forefront of the global battery revolution. The project is a collaboration of seven university and eight industrial partners, each bringing unique capabilities to the development of Li-S batteries. We contribute to the cathode material design and pouch cell manufacturing technologies to produce high-performance practical Li-S batteries. We also work on solid-state electrolytes and Na-ion batteries.

Articles from the Group

Why are Solid-State Electrolytes Gaining Popularity?

Many people consider all-solid-state batteries (batteries with a solid-state electrolyte rather than a conventional liquid electrolyte) to be the next step in battery technology and the funding in solid-state electrolyte research reflects this. By 2031, the market for solid-state electrolytes is expected to reach $8 billion with large companies such as Audi and BMW currently investing heavily. At first glance, this seems strange because solid-state electrolytes have a lower conductivity for Li-ions and are far more expensive and difficult to make - so is it all hype or is there something more going on?

Although the technology is not there yet, solid-state electrolytes promise to increase the energy density, power density and cycle lifetime of batteries whilst also making them more safe. In current, liquid electrolyte Li-ion batteries, every time the battery is charged and discharged, lithium is transferred from one electrode to the other. If a pure lithium anode is used, the lithium deposition becomes uneven leading to the formation of whisker-like lithium dendrites through the electrolyte. When these reach the cathode, the battery is shorted and no longer usable. Instead of pure lithium, lithium-containing carbon is used as an anode in commercial cells. This prevents lithium dendrites forming but means a lot of the anode is carbon and not lithium - the active material in the battery. Even more problematic is the risk of the liquid electrolyte catching fire or exploding. This occurs when the heat that is inevitably released during battery operation, heats the electrolyte to above its combustion temperature and the electrolyte ignites. 

Solid electrolytes solve these problems because solids typically have a much higher combustion temperature and so are far less likely to ignite. They also form a physical barrier that may prevent lithium dendrites from growing through them. This means all-solid-state batteries are much safer and can use pure lithium anodes, achieving huge performance improvements. With approximately 500 kg of Li-ion batteries in a standard electric car, these improvements in safety and performance are critical for the successful growth of the electric vehicle industry and constitute the main reasons why car manufacturers are investing so heavily in the technology. This investment is primarily focussed on finding novel solid electrolyte materials with ionic conductivities to rival liquid electrolytes and integrating these materials into functional batteries.

James Moloney, 14/9/2021