Amin
Salehi-Khojin, assistant professor of mechanical and industrial engineering
(right),
and postdoctoral
research associate Mohammad Asadi with their specially modified
differential
electrochemical mass spectrometry (DEMS) instrument.
PHOTO CREDIT: UIC
College of Engineering
(January 20, 2016) Lithium-air
batteries hold the promise of storing electricity at up to five times the
energy density of today’s familiar lithium-ion batteries, but they have
inherent shortcomings. Researchers at the University of Illinois at Chicago
have helped prove that a new prototype is powered by a surprising chemical
reaction that may solve the new battery’s biggest drawback.
The findings are reported in the Jan. 11 issue of Nature.
Today’s lithium-air batteries (in which the metallic lithium
of the anode, or positive terminal, reacts with oxygen from the air) hold great
promise, because they store energy in the form of chemical bonds of oxide
compounds. Versions tested to date have stored and released energy from lithium
peroxide, an insoluble substance that clogs the battery’s electrode.
Battery scientists at the U.S. Department of Energy’s
Argonne National Laboratory developed a prototype that they claimed had the
surprising ability to produce only lithium’s superoxide, not peroxide, as the
battery discharges. Unlike troublesome lithium peroxide, lithium superoxide
easily breaks down again into lithium and oxygen, thus offering the possibility
of a battery with high efficiency and good cycle life.
The Argonne group designed the battery to consume one
electron rather than two and produce the superoxide, said UIC’s Amin
Salehi-Khojin, assistant professor of mechanical and industrial engineering.
But it was difficult to prove the reaction took place.
“Ex-situ analysis is not accurate enough to prove such a big
claim,” he said.