Wednesday, January 23, 2013

New Batteries Pack More Punch

Electric cars face severe limits in how far they can drive before running out of juice. Better batteries that can both store more energy and give it up quickly are essential for extending that range.
 For now, the new batteries can power only small devices. But if the strategy can be made to work on a larger scale, a task more difficult than just using more battery material, it could give electric car makers the jolt they need.
Today's most popular rechargeables, lithium ion batteries, are made from negative and positive electrodes separated by an electrolyte through which positively charged lithium ions can flow back and forth. In most such cells, the negative electrode is made of graphite, a form of layered carbon, whereas the positive electrode is made from lithium cobalt oxide or a related material. During use, lithium ions stored in the graphite flow to the lithium-based electrode, where they form chemical bonds with oxygen atoms, a reaction that generates an electric current. When the battery is recharged, the lithium-oxygen bonds break and an electric voltage pushes the ions back into the graphite.

for more information:
Robert F. Service , Science Magazine

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