Progress towards a more powerful lithium-air battery

By RELAXNEWS | 2 November 2015

LONDON: A new kind of chemistry could power lithium-air batteries over long-standing technological hurdles, leading toward a product that may one day be strong enough to replace gasoline in cars, researchers said recently.

Rechargeable batteries have been around for decades - the lithium-ion battery that powers many mobile devices is marking its 25th anniversary next year - but scaling up the technology to the level of powering automobiles has proven difficult.

Researchers have spent years looking into a kind of battery known as lithium-air, or lithium-oxygen, which could provide 10 times more power, and possibly enough energy density to compare with gasoline, but these too have been plagued by practical problems.

While an ultimate lithium-air battery remains at least a decade away, researchers at the University of Cambridge say they have patented a technology that overcomes some of the major obstacles.

Senior author Clare Grey, a chemistry professor at the University of Cambridge, said her team's "significant achievement" has been making strides toward high capacity "and the fact that we've taken the efficiency down into numbers that compete with current lithium-ion technology," she told reporters.

Since the technology is still in the lab phases, it is not possible to directly compare it to currently available technologies, she said.

But the latest approach has shown increased energy efficiency of up to 93 percent, and does so by relying on a very different kind of chemistry than previous attempts, employing lithium hydroxide (LiOH) instead of lithium peroxide (Li2O2).

The "demonstrator relies on a highly porous, 'fluffy' carbon electrode made from graphene (comprising one-atom-thick sheets of carbon atoms), and additives that alter the chemical reactions at work in the battery, making it more stable and more efficient," said a statement from the University of Cambridge.

The result is another step on the path toward to a more practical, high-powered battery, said Grey.

"We're excited by the chemistry, but we've also got quite a lot of work to do in particular to understand the mechanisms of this chemistry and optimize it and to work on getting it closer to a higher rate system."

The paper is published in the US journal Science.