Lithium-oxygen batteries are getting an energy boost

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A new type of lithium-oxygen battery could pack more energy and last longer than its predecessors.

Lithium-oxygen batteries, which are more energy-dense and made of more sustainable materials than typical lithium-ion cells, are promising candidates for the next generation of rechargeable batteries (SN: 1/21/17, p. 22). But lithium-oxygen batteries aren’t widely used yet because they die so quickly. By tweaking the building materials, researchers have now constructed a lithium-oxygen battery that can release nearly 100 percent of its stored charge and be recharged at least 150 times. This battery, described in the Aug. 24 Science, could one day become a more reliable, energy-dense power source for electric cars or other electronics.

Lithium-oxygen cells are made of two electrodes, an anode and a cathode, separated by a substance called electrolyte. When the battery is powering another device, oxygen molecules on the cathode combine with lithium ions from the electrolyte to form a solid compound called lithium peroxide. That chemical reaction releases energy. Recharging the battery breaks apart the lithium peroxide, returning oxygen and lithium to their starting positions.

But forging lithium peroxide generates several unwanted chemical by-products, which wastes energy. As a result, a lithium-oxygen battery may be able to deliver only about 80 percent of its stored electric charge to the device it’s powering. These pesky chemicals also damage the battery’s electrolyte and cathode, so the batteries often fail after only a few dozen recharges, says Larry Curtiss, a materials chemist at Argonne National Laboratory in Lemont, Ill., who was not involved in the work.



FiveWordsForTheFuture - Sep 20, 2018 | Electricity, Energy, Sustainability
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