Research towards limitless Li-ion battery lifetime

Power Electronics / Power Management

15 June 2016 Power Electronics / Power Management Electronics Technology

Researchers from the University of California, Irvine, have invented nanowire-based battery material that can be recharged hundreds of thousands of times – a breakthrough that could lead to commercial batteries with greatly lengthened lifespans for computers, smartphones, appliances, cars and spacecraft.

Scientists have long sought to use nanowires in batteries. Thousands of times thinner than a human hair, they’re highly conductive and feature a large surface area for the storage and transfer of electrons. However, these filaments are extremely fragile and don’t hold up well to repeated discharging and recharging, or cycling. In a typical lithium-ion battery, they expand and grow brittle, which leads to cracking.

The researchers solved this problem by coating a gold nanowire in a manganese dioxide shell and encasing the assembly in an electrolyte made of a Plexiglas-like gel. The combination is reliable and resistant to failure. The study leader, UCI doctoral candidate Mya Le Thai, cycled the testing electrode up to 200 000 times over three months without detecting any loss of capacity or power, and without fracturing any nanowires.

This was a marriage of hard work and serendipity, according to senior author, Reginald Penner. “Mya was playing around, and she coated this whole thing with a very thin gel layer and started to cycle it,” said Penner, chair of UCI’s chemistry department. “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 5000 or 6000 or 7000 cycles at most.”

The researchers think the goo plasticises the metal oxide in the battery and gives it flexibility, preventing cracking. “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.”

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Research towards limitless Li-ion battery lifetime

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