New Improved Lithium-Ion Batteries That Last Longer in Extreme Cold

If you have an electric car and drive in the cold, you’re likely aware of the lowered performance and range when temperatures drop below freezing. Even if you live somewhere warm, you might see the same effect in your mobile phone during a ski trip, finding your percentage charge quickly waning despite minimal usage.

When temperatures fall below freezing, cell phones need to be recharged frequently, and electric cars have shorter driving ranges. This is because their lithium-ion batteries’ anodes get sluggish, holding less charge and draining energy quickly. To improve electrical performance in the extreme cold, researchers reporting in ACS Central Science have looked into replacing the traditional graphite anode in a lithium-ion battery with a bumpy carbon-based material.

Lithium-ion batteries are great for powering rechargeable electronics because they can store a lot of energy and have a long life duration. But when temps fall below freezing, these energy sources’ electrical performance can be affected, and when conditions are cold enough, they can fail to transfer any charge at all.

Recently, scientists determined that the flat orientation of graphite in the anode is responsible for the drop in a lithium-ion battery’s energy storage capacity in the cold. So, Xi Wang, Jiannian Yao, and colleagues wanted to modify the surface structure of a carbon-based material to improve the anode’s charge transfer process.

The researchers heated a cobalt-containing zeolite imidazolate framework (known as ZIF-67) at high temperatures then the team tested the material’s electrical performance as the anode, with lithium metal as the cathode, inside a coin-shaped battery. The anode demonstrated stable charging and discharging at temperatures from 77°F to -4°F (25°C to -20°C) and maintained 85.9% of the room temperature energy storage capacity just below freezing.

In comparison, lithium-ion batteries made with other carbon-based anodes, including graphite and carbon nanotubes, held almost no charge at freezing temperatures, Incorporating the bumpy nanosphere material into lithium-ion batteries could open up the possibilities for using these energy sources at extremely low temperatures, the researchers say