University of California, Irvine researchers have invented nanowire-based battery material that can be recharged hundreds of thousands of times, moving us closer to a battery that would never require replacement. The work 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.

UCI researchers have 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 csientists 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. Batteries typically die in dramatic fashion after 5,000 or 6,000 or 7,000 cycles at most.

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