A large consortium led by the University of Bath, investigating ways of improving energy storage in batteries, has made a significant step towards creating higher energy density lithium-ion batteries. The research paves the way for increasing the range of future electric vehicles.

Scientists based at the University of Oxford as part of the Faraday Institution CATMAT project researching next-generation cathode materials have made a significant advance in understanding oxygen-redox processes involved in lithium-rich cathode materials.

The paper, published in Nature Energy, proposes strategies that offer potential routes to increase the energy density of lithium-ion batteries.

Increasing the range of electric vehicles demands battery materials that can store more charge at higher voltages in order to achieve a higher “energy density”.

There are a limited number of ways to increase the energy density of lithium-ion cathode materials. Most current cathode materials are layered transition metal oxides incorporating, e.g. cobalt, nickel and manganese. One research route involves storing charge on the oxide ions as well as on the transition metal ions.

Use of such oxygen-redox materials to increase cathode energy density has been promising for some years, but realising their full potential in commercial batteries has been hampered by the structural changes they experience during their first charge, which are predominantly irreversible, and which give rise to a significant drop in the voltage available on subsequent discharge and future cycles.

By collaborating with researchers at Diamond Light Source, Faraday Institution researchers have successfully uncovered a mechanism for oxygen-redox that explains these structural changes.

Professor Saiful Islam, from the University of Bath’s Department of Chemistry and CATMAT Principal Investigator said: “These findings are highly significant and are an important milestone towards increasing the range of future electric vehicles.”