The study, published in Nature Energy, presented evidence from laboratory-scale tests which indicates that keeping batteries under controlled pressure during charge and discharge cycles may double their operational life. If replicated at scale, the approach could reduce the number of batteries requiring recycling or disposal, while also lowering demand for critical materials such as nickel and cobalt.

At the most basic level, batteries are composed of an anode, a cathode and an electrolyte. As a lithium-ion battery goes through each charge and discharge cycle, lithium ions shuttle from the anode to cathode and back again. This causes the battery to expand and contract.  

To address this, the research team built a device that squeezes a type of battery known as a pouch cell using pneumatic ‘bellows’ – air-filled cushions that function as a self-adjusting clamp. The bellows maintain a continuous pressure, while a sensor monitors tiny volume changes as the battery charges and discharges.  

The findings show that the pressure must remain within a narrow ‘Goldilocks’ range, with the team identifying an optimal level of around 12.5 bar. Deviations from this range were found to accelerate degradation: excessive pressure led to lithium plating on the anode, while insufficient pressure caused cracking in the cathode.

‘We found that when you keep the pressure on them relatively constant throughout each charge and discharge cycle, it’s much better for the overall lifetime of the battery,’ said Professor Michael De Volder, from Cambridge’s Department of Engineering, who co-led the research. ‘If you press too hard, the anode is unhappy. If you don’t press hard enough, the cathode starts degrading.’

It is hoped that longer-lasting electric vehicle (EV) batteries could reduce the volume of raw materials that need to be mined to produce new batteries. ‘We’ve produced a solution for cleaner electric cars, but we have to make sure that on the back of it, we are not creating new ecological disasters in other parts of the world,’ said De Volder. ‘If we can reduce the pressure on these mining operations a bit, that would be another important benefit.’

The technology has been tested at laboratory scale but will need to be scaled up to represent commercial battery applications.  

The research was supported in part by the European Research Council, the Faraday Institution and the Engineering and Physical Sciences Research Council, part of UK Research and Innovation.