Study suggests route to improving rechargeable lithium batteries

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Most of today’s lithium-ion batteries, which power everything from cars to phones, use a liquid as the electrolyte between two electrodes. Using a solid electrolyte instead could offer major advantages for both safety and energy storage capacity, but attempts to do this have faced unexpected challenges.

Most of today’s lithium-ion batteries, which power everything from cars to phones, use a liquid as the electrolyte between two electrodes. Using a solid electrolyte instead could offer major advantages for both safety and energy storage capacity, but attempts to do this have faced unexpected challenges.

Researchers now report that the problem may be an incorrect interpretation of how such batteries fail. The new findings, which could open new avenues for developing lithium batteries with solid electrolytes, are reported in the journal Advanced Energy Materials, in a paper by Yet-Ming Chiang, the Kyocera Professor of Ceramics at MIT; W. Craig Carter, the POSCO Professor of Materials Science and Engineering at MIT; and eight others.

The electrolyte in a battery is the material in between the positive and negative electrodes — a sort of filling in the battery sandwich. Whenever the battery gets charged or drained, ions (electrically charged atoms or molecules) cross through the electrolyte from one electrode to the other.

But these liquid electrolytes can be flammable, and they’ve been responsible for some fires caused by such batteries. They are also prone to the formation of dendrites — thin, fingerlike projections of metal that build up from one electrode and, if they reach all the way across to the other electrode, can create a short-circuit that could damage the battery.

Read more at Massachusetts Institute of Technology