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nanotimes News in Brief

Energy // Inventing Self-repairing Batteries

© Based on Material by ANL, US

12-01 :: January 2012

U.S. Department of Energy‘s (DOE) Argonne Natio- nal Laboratory are exploring ways to design batteries that heal themselves when damaged.

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“This would help electronics survive daily use – both the long-term damage caused by charging over and over again, and also the inevitable physical damage of everyday life,” said Jeff Moore, a UIUC scientist on the team.

Scientists think that loss of electrical conductivity is what causes a battery to fade and die. Theories abound on the specific molecular failures; perhaps chemicals build up on electrodes, or the electrodes themselves pull away. Perhaps it‘s simply the inevi- table stress fractures in materials forced to expand and contract repeatedly as the battery is charged and used.

In any case, the battery‘s storage capacity drops due to loss of electrical conductivity. This is what the team wants to address. The idea is to station a team of “emergency repairmen” already contained in the battery. These are tiny microspheres, each smaller than a single red blood cell, and containing liquid metal inside. Added along with the battery com-

ponents, they lie dormant for most of the battery‘s lifetime.

But if the battery is damaged, the capsules burst open and release their liquid metal into the battery. The metal fills in the gaps in the electrical circuit, connecting the broken lines, and power is restored.

Capsules could be designed to be triggered by diffe- rent events – some that respond to physical damage and others that respond to overheating, for example. This would allow scientists to tailor the contents of the different capsules to repair specific situations.

Microcapsules have been manufactured in large scale since the 1950s. When you press your pencil down on carbonless copy paper, microcapsules full of ink

team of researchers from the University of Illinois at Urbana-Champaign (UIUC) and the