Tech Briefs by Andrew Corselli 6/22/2023
Scientists developed a new and safer electrolyte for Li-ion batteries that works as well in sub-zero conditions as it does at room temperature.Many owners of electric vehicles (EVs) worry about how their battery will perform in very cold weather. However, a new battery chemistry may have solved that problem.
In current Li-ion batteries, the main problem lies in the liquid electrolyte. This key battery component transfers charge-carrying particles — ions — between the battery’s two electrodes, causing the battery to charge and discharge. But the liquid begins to freeze at sub-zero temperatures. This condition, of course, severely limits the effectiveness of charging electric vehicles in cold regions and seasons.
To address this issue, a team from the U.S. Department of Energy’s (DOE) Argonne and Lawrence Berkeley national laboratories developed a fluorine-containing electrolyte that performs well — even when the temperature drops below zero.
“Our team not only found an antifreeze electrolyte whose charging performance does not decline at -4 °F, but we also discovered, at the atomic level, what makes it so effective,” said Argonne group leader Zhengcheng “John” Zhang.
This new electrolyte shows promise of working for batteries in EVs as well as in energy storage for electric grids and consumer electronics.
In today’s lithium-ion batteries, the electrolyte is a mixture of lithium hexafluorophosphate and carbonate solvents, such as ethylene carbonate. The solvents dissolve the salt to form a liquid. When a battery is charged, the liquid electrolyte shuttles Li-ions from the cathode to the anode. These ions migrate out of the cathode, then pass through the electrolyte on the way into the anode. While being transported through the electrolyte, they sit at the center of clusters of four or five solvent molecules.
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The antifreeze electrolyte has a bonus property: It will not catch fire.More:
https://www.techbriefs.com/component/content/article/tb/stories/blog/48448
