UCI chemist Reginald Penner (shown) and doctoral candidate Mya Le Thai have developed a nanowire-based material that allows lithium-ion batteries to be recharged hundreds of thousands of times. Photo: Daniel A. Anderson/UCI.Researchers at the University of California, Irvine (UCI) have invented a metal nanowire-based battery material that can be recharged hundreds of thousands of times. This breakthrough could lead to the development of commercial batteries with greatly extended lifespans for use in computers, smartphones, appliances, cars and spacecraft.
Scientists have long sought to use metal nanowires in batteries. Thousands of times thinner than a human hair, metal nanowires are highly conductive and boast a large surface area for storing and transferring 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, nanowires can expand and grow brittle, which leads to cracking.
UCI researchers have now solved this problem by coating a gold nanowire in a manganese dioxide shell and then encasing the assembly in an electrolyte made of a Plexiglas-like gel. The resultant material is reliable and resistant to failure.
The study leader, UCI doctoral candidate Mya Le Thai, cycled an electrode made from this material up to 200,000 times over three months without detecting any loss of capacity or power and without fracturing any nanowires. The findings are published in a paper in Energy Letters.
Hard work combined with serendipity paid off in this case, 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," he added, "because these things typically die in dramatic fashion after 5000 or 6000 or 7000 cycles at most."
The researchers think the gel plasticizes the manganese dioxide in the battery, giving it flexibility and preventing it from 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."
This story is adapted from material from the University of California, Irvine, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.