The stability and performance of lithium-oxygen batteries look set to be vastly improved with a tailored electrolyte that could herald the next generation of rechargeable batteries.
This is the claim of scientists led by Liverpool University, in partnership with Johnson Matthey PLC and Loughborough University, who have designed a blend of materials that are stable with the Li metal anode of lithium-oxygen batteries.
The lithium-oxygen (Li-O2) battery (or lithium-air battery), consisting of Li-metal and a porous conductive framework as its electrodes, releases energy from the reaction of oxygen from the air and lithium. The burgeoning technology has the potential to provide much greater energy storage than a conventional lithium-ion battery.
In a paper published in Advanced Functional Materials, Professor Laurence Hardwick from Liverpool University’s Stephenson Institute for Renewable Energy (SIRE) and colleagues characterised and developed electrolyte formulations that minimise side reactions and enable cycle stability.
According to lead author of the paper Dr Alex Neale, who is also with SIRE, the research demonstrates that the reactivity of certain electrolyte components can be switched off by precise control of component ratios.
In a statement, Dr Neale said: “The ability to precisely formulate the electrolyte using readily-available, low volatility components enabled us to specially tailor an electrolyte for the needs of metal-air battery technology that delivered greatly improved cycle stability and functionality.
“The outcomes from our study really show that by understanding the precise coordination environment of the lithium-ion within our electrolytes, we can link this directly to achieving significant gains in electrolyte stability at the Li metal electrode interface and, consequently, enhancements in actual cell performance.”
“Li-O2 batteries have remarkably high theoretical specific energy, and therefore the realisation of a practical and truly rechargeable Li-O2 device with even a fraction of the theoretical capacity could outperform state-of-the-art lithium-ion cells,” added Dr Pooja Goddard from Loughborough University’s Department of Chemistry. “However, one of the key technological barriers to development is the stability of materials in Li-O2 cells. If the stability and performance of Li-O2 batteries can be optimised, Li-O2 devices could enhance for example driving range capacity significantly for electric vehicles.”
Work still needs to be done to improve the stability of materials at the cathode but the breakthrough is said to mark a significant milestone in the future of energy storage, with Li-O2 cells expected to have up to 10 times the charge capacity of current batteries.
Enrico Petrucco from Johnson Matthey PLC said: “This work exemplifies a useful electrolyte design strategy for Li-air batteries underpinned with excellent science within a great collaboration. This moves us another step closer towards practical routes to overcome complex Li-air challenges.”
The collaborative research between the two University research groups in Liverpool and Loughborough and Johnson Matthey PLC was made possible with support from an Innovate UK grant.