Bumpy graphite anodes could help batteries cope with the cold

Lithium-ion batteries have transformed the modern world and are crucial to the energy transition, but they don't do well in the cold.

When temperatures fall below freezing, phones have to be charged more frequently, and electric cars lose some of their range.

This is because the anodes of their lithium-ion batteries hold less charge and drain energy more quickly. Now, researchers have developed a new type of anode, replacing the traditional graphite with a bumpy carbon-based material that maintains its storage capacity down to -35C. 

The work, published in the journal ACS Central Science, was conducted by Chinese researchers Xi Wang, Jiannian Yao and their colleagues. They created 12-sided carbon nanospheres with bumpy surfaces that had excellent electrical charge transfer capabilities. 

Then, the team tested the electrical performance of their new material as the anode in a coin-shaped battery. It demonstrated stable charging and discharging at a wide range of temperatures, and held their charge below freezing – a much better performance than traditional lithium-ion batteries. The new material maintained 85.9% of its room temperature energy storage capacity even when temperatures dropped below freezing. 

At -35C, the bumpy nanosphere anode was still rechargeable and capable of discharging nearly 100 per cent of the charge put into the battery. The researchers said that incorporating this material into lithium-ion batteries could allow them to be used in extremely low temperatures – in colder climates, or to power equipment on space missions.