Battery coating to improve lithium metal anodes

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Coating a lithium ion battery made with metal with an organic compound called methyl viologen can stabilise performance, eliminate dendrite growth and increase the lifetime of the battery by more than three times compared to the current standard electrolyte used with lithium metal anodes, say a team of researchers at the University of California, Riverside.

"This has the potential to change the future," said adjunct assistant professor Chao Wang. "It is low cost, easily manipulated and compatible with the current lithium ion battery industry."

The success of lithium metal anodes could enable many battery technologies, including lithium metal and lithium air, which could potentially increase the capacity of lithium-ion batteries by five to 10 times. Lithium metal anodes are also lighter and less expensive.

The problem with lithium ion batteries made with metal is that during charge cycles they uncontrollably grow dendrites.

The researchers designed a new strategy to form a stable coating to enhance the lifetime of lithium-metal anodes. They used methyl viologen, which has been used in other applications because of its ability to change colour when reduced.

The methyl viologen molecule used by the researchers can be dissolved in the electrolytes in the charged states. Once the molecules meet the lithium metal, they are immediately reduced to form a stable coating on top of the metal electrode.

Wang cautioned that while the coating improves battery performance, it isn't a way to prevent batteries from catching fire.