Accidental discovery may give new life to rechargeable batteries

If you’ve owned a laptop computer or a smartphone for any length of time, you’ve probably had to replace the battery. That’s because after repeated cycles of charging and discharging, lithium-ion batteries tend to lose their ability to hold a charge. The electrodes get brittle and wear out.

But an apparently serendipitous discovery by a graduate student at the University of California at Irvine (UCI) could lead to commercial batteries for computers, phones, appliances, and cars with lifespans so long they might never need replacement.

UCI doctoral candidate Mya Le Thai was studying the use of nanowires as battery electrodes when she stumbled upon her discovery. A thousand times thinner than a human hair, nanowires are very conductive and provide an electrode with a much larger surface area for better electricity storage. But they’re very fragile and grow brittle and crack under repeated recharging.

Thai found that by coating the wires with a manganese dioxide shell and encasing the electrodes and the interior electrolyte with a Plexiglas-like gel, she could run her battery up to 200,000 charging cycles without any loss of capacity.

“That was crazy because these things typically die in dramatic fashion after 5,000 or 6,000 or 7,000 cycles, at most,” said Reginald Penner, chair of UCI’s chemistry department.

The research, published last month in the American Chemical Society’s journal, Energy Letters, is still in the early stages, and it’s not known when the technology might make a commercial debut. But Thai is confident it will.

“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,” she said.