Lithium-ion batteries: Bumpy components could work better in the freezing cold

Lithium-ion batteries often lose their charge at sub-zero temperatures but a design incorporating bumps into one of the main components makes them work much better

By Karmela Padavic-Callaghan

Bumpy components for lithium-ion batteries may make them hold charge better in freezing cold temperatures.

Rechargeable lithium-ion batteries are used in many electronic devices raging from iPhones to electric vehicles. However, at temperatures below freezing, such batteries can take days to fully recharge or they store a lot less energy. For example, the range of electric vehicle can become 30 per cent shorter when very cold.

Xi Wang at Beijing Jiaotong University in China and his colleagues found that changing the shape of a lithium-ion battery’s anode could make it work better at low temperatures.

Anodes are involved in the charging and discharging of a battery and are normally flat, but the team engineered a battery with a curved and bumpy one.

The team found that their bumpy battery retained around 86 per cent of its energy at -20°C compared to at room temperature. A similarly sized conventional lithium-ion battery could only hold around 3 per cent of its energy at the same cold temperature. Overall, batteries with the new anodes lasted longer than standard lithium-ion batteries at temperatures between 25°C and -20°C.

Charging and discharging a battery relies on charged particles flowing to and from the anode. Near freezing, most of the particles don’t have enough energy to make the trip, so the battery fails to power devices or recharge.

Making the anode bumpy and spherical puts charged particles closer to each other meaning they cluster and interact, lowering the overall amount of energy they need to move.

So far, the method has only been tested in small coin-shaped batteries like those used in watches. The team’s next challenge is to devise a way for reliably making many larger anodes with their bumpy structure for larger batteries.

Making batteries for cold temperatures may also help researchers engineer batteries that perform better at room temperature as well, says Ping Liu at University of San Diego.

Journal reference: ACS Central Science, DOI: 10.1021/ascentsci.2c00411