Scientists claim 'accidental' breakthrough in ever-lasting batteries

Nanowire technology could mean batteries that can be recharged 100,000 times

University researchers claim to have uncovered a battery technology that could enable batteries to be developed that can be recharged hundreds of thousands of times - with no loss of capacity.

The team at the University of California at Irvine (UCI) say that the approach is based on 'nanowires', a material that is several thousand times thinner than a human hair, extremely conductive and has a surface area large enough to support the storage and transfer of electrons.

Mya Le Thai, a PhD candidate at the University, explained the breakthrough in a paper published this week.

Nanowires are extremely fragile and don't usually hold up well to repeated discharging and recharging, or cycling. They expand and grow brittle in a typical lithium-ion battery, but Le Thai's team fixed this by coating a gold nanowire in a manganese dioxide shell and then placing it in a Plexiglas-like gel to improve its reliability. All by accident.

The technique could lead to laptop, smartphone and tablet batteries that last forever - if the batteries can be cost-effectively produced.

Richard Penner, chairman of UCI's chemistry department, said: "Mya was playing around and she coated this whole thing with a very thin gel layer and started to cycle it.

"She discovered that just by using this gel she could cycle it hundreds of thousands of times without losing any capacity. That was crazy, because these things typically die in dramatic fashion after 5,000 or 6,000 or 7,000 cycles at most."

The battery-like structure was tested more than 200,000 times over a three-month span, and the researchers reported no loss of capacity or power.

"The coated electrode holds its shape much better, making it a more reliable option," Thai said. "This research proves that a nanowire-based battery electrode can have a long lifetime and that we can make these kinds of batteries a reality."

The breakthrough also paves the way for commercial batteries that could last a lifetime in appliances, cars and spacecraft.

British fuel-cell maker Intelligent Energy Holdings announced earlier this year that it is working on a smartphone battery that will need to be charged only once a week.

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