Breakthough in lithium-air batteries

Lithium-air batteries excite alternative energy fans because they can store up to ten times the energy of today's lithium-ion batteries, an energy density similar to that of gasoline. But skeptics note that lithium peroxide by-products in the lithium-air reactions quickly contaminate the cathode, killing the battery, and the open design required to get enough air to the reaction point for efficiency poses problems.

Michael Thackeray elucidates the problems of lithium-air batteries in the short video above, at the outset of a U.S. Dept. of Energy funded project at Argonne National Laboratory. In spite of these obstacles, Argonne refers to rechargeable lithium-air batteries as "the ultimate battery chemistry," because "a rechargeable Lithium/Air battery can potentially store ten times the energy of a Lithium/Ion battery of the same weight, making practical widespread use of fully electric cars."

Collaborative efforts of researchers working on the Lithium-air challenge have led to development of a battery that the team believes could avoid the problem of peroxide build-up. But the claim was difficult to prove without further evidence.

In their newest report, published in Nature, the scientists have used various techniques and found no evidence for formation of lithium peroxide (that's science-speak for "we proved our suspicion that we have indeed invented a lithium-air battery technology that works").

They additionally found the reason why their battery works: the spacing of the iridium catalyst nanoparticles in the reduced graphene oxide (rGO) cathode favor the production of lithium superoxide (LiO2) and inhibit peroxide (Li2O2) generation.

The lithium superoxide can easily dissociate back into lithium and oxygen. Avoiding the loss of oxygen tied up in lithium peroxide could enable the development of a closed system lithium-air battery, which would make the units safer and more efficient,

If you search for the future of batteries, two major memes pop out. One is flow-through batteries, relying on energy stored in engineered liquids which would be dumped for recycling and "refueled" at pumping stations that would someday replace gas stations. The other is lithium-air batteries. Although the remaining issues will still require years to solve and test, the lithium-air battery just got one step closer to reality.

Tags: Batteries | Energy

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