Despite the widespread use of batteries today, a major limitation is the fact that they can reach the end of their usefulness after a certain number of recharge cycles.
Now researchers at the University of California Irvine have greatly extended the lifespan of batteries, with a nanowire-based battery material that can be recharged hundreds of thousands of times.
Nanowires are well-suited for batteries, since they are thousands of times thinner than a human hair, and thus present large surface areas for the storage and transfer of electrons. They are also highly conductive.
However, scientists have been unable to use them effectively in batteries, because they are very fragile and tend to break down with repeated discharge and recharge cycles.
The breakthrough comes by coating a gold nanowire in a manganese dioxide shell, then encasing the assembly in an electrolyte made of a Plexiglas-like gel.
The reliable and failure-resistant combination could lead to commercial batteries with drastically lengthened lifespans, which could lead to increased durability for devices like laptops, mobile devices, cars, spacecraft and industrial systems.
The leader of the study, a doctoral candidate Mya Le Thai, cycled the prototype electrode up to 200,000 times over three months. The repeated charge/discharge cycle did not result in any loss of capacity or power, nor did the nanowires fracture.
While nanowires tend to be destroyed after 5000 to 7000 cycles, Mya found that by coating the assembly in a very thin gel layer, she could cycle it hundreds of thousands of times without losing any capacity.
The researchers theorise that the gel plasticises the metal oxide in the battery, giving it enough flexibility to prevent cracking.
With this breakthrough, the researchers showed that a nanowire-based battery electrode can have a long lifetime, and thus they can start working on making these batteries a reality.
Doctoral candidate Mya Le Thai holding one of her nanowire batteries. Photo: Steve Zylius/UCI