DOE national labs develop electrolyte to help electric vehicle batteries weather cold temps

Frigid temperatures are the bane of lithium-ion batteries, making them an issue for the expanding electric vehicle market, but now, scientists from the U.S. Department of Energy’s (DOE) Argonne and Lawrence Berkeley national laboratories may have found a solution.

A critical component of the modern lithium-ion battery is liquid electrolyte, which transfers ions between the battery’s electrodes, allowing the charging and discharging of energy. However, that liquid begins to freeze at sub-zero temperatures, limiting charging efficacy. Scientists at the national labs played around with battery chemistry and created an electrolyte containing fluorine, allowing lithium-ion batteries to operate as surely in sub-zero conditions as at room temperature.

“Our team not only found an antifreeze electrolyte whose charging performance does not decline at minus 4 degrees Fahrenheit, but we also discovered, at the atomic level, what makes it so effective,” Zhengcheng ​“John” Zhang, a senior chemist and group leader in Argonne’s Chemical Sciences and Engineering division, said.

Basically, Zhang and his colleagues found how to edit the atomic structure of electrolyte solvents to design new electrolytes tailored to users’ needs. Through investigation of fluorine-containing solvents and testing with laboratory cells, they found a composition with the lowest energy barrier for releasing lithium ions at sub-zero temperatures.

The result is a battery capable of use in electric vehicles as well as energy storage for grids and consumer electronics such as computers and phones. As a bonus, the new electrolyte can’t catch fire, unlike carbonate-based electrolytes currently used in batteries. Now, the researchers must find a partner to bring the concept to market.

“We are patenting our low-temperature and safer electrolyte and are now searching for an industrial partner to adapt it to one of their designs for lithium-ion batteries,” Zhang said.

Research undertaken by Zhang and his team was funded by the DOE Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.