Nanowire tech offers ground-breaking battery charge capacity
Thu 21 Apr 2016
A nanowire-based battery has been designed by University of California, Irvine (UCI) researchers which can be exposed to hundreds and thousands of repeated charge cycles without compromising capacity.
The breakthrough could lead to significant advancements in long-life commercial batteries used in a variety of applications, ranging from computers and smartphones to cars and spacecraft.
Nanowire technologies have long been hailed for their highly conductive capabilities and large surface area for the storage and transfer of electrons. These properties are achieved in an incredibly tiny filament – a thousand time thinner than a human hair. Nanowires are however very fragile and do not typically perform well when exposed to continuous charge cycles. Used in a standard lithium-ion battery, the wires expand and can become brittle over time, leading to fracturing.
The team of UCI scientists has now found a way of avoiding this fragility by covering gold filaments in a manganese dioxide coating and placing the material in a gel electrolyte. The researchers argue that this combination offers a reliable and failure-proof solution.
Research lead Mya Le Thai describes testing the new electrode across 200,000 cycles over the course of three months. She explained in her findings, published today in the American Chemical Society’s Energy Letters, that after this extended period there was no evidence of capacity or power loss, or frayed nanowires.
“Mya was playing around, and she coated this whole thing with a very thin gel layer and started to cycle it,” noted senior author Reginald Penner, chair of the UCI 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 5,000 or 6,000 or 7,000 cycles at most,” he added.
The scientists believe that the gel works as a ‘plasticizer’ for the metal oxide in the battery, offering greater flexibility and protecting against cracks.
“The coated electrode holds its shape much better, making it a more reliable option,” said Thai. “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.”