Lithium-air battery breathes new hope for electric vehicles

By Arman Kazemi

November 5, 2015

Researchers at the University of Cambridge have developed a working lithium-oxygen battery that is over 90 per cent efficient and can be recharged over 2,000 times.

The results bode well for the development of electric cars that can drive long distances on a single charge.

“The current results are extremely exciting,” Clare Grey, the paper’s senior author, said in a press release. “We are still very much at the development stage, but we’ve shown that there are solutions to some of the tough problems associated with this technology.”

Lithium-oxygen batteries could have an energy density 10 times that of a conventional lithium-ion battery, similar to that of gasoline. If such batteries could be commercially produced, the authors claim, they would be a fifth of the weight and cost of existing batteries, and would last much longer on a single charge.

But previous experimental lithium-air batteries have been plagued with problems, including low efficiency and unwanted chemical reactions.

The recent study, published in the journal Science, used an experimental battery that produced lithium hydroxide instead of lithium peroxide, a solid deposit that had been produced by earlier designs. While lithium peroxide built up and was hard to remove when the battery was recharged, lithium hydroxide decomposed easily upon recharge.

Additionally, the team’s positive electrode was made up of carbon sheets one atom thick that are porous and resilient. The result was a much more efficient battery that allows by-products to build up and dissolve again as it recharges.

But, as the report’s authors admit, the commercial applications of such technology could be about a decade out.

First off, the test battery only works with pure oxygen, not regular air, which makes it impractical for use in electric cars. It also takes days to recharge.

“What we’ve achieved is a significant advance for this technology and suggests whole new areas for research,” Grey said. “We haven’t solved all the problems inherent to this chemistry, but our results do show routes forward towards a practical device.”



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