By Sara Chen
UC Irvine Ph.D candidate Mya Le Thai published a paper last week in the ACS Energy Letters alongside UCI Chemistry Professor Dr. Reginald Penner, outlining her “accidental” invention of a battery which lasts thousands of times longer than a typical model.
Thai created gel-coated nanowires that didn’t show any sign of breaking down, even after hundreds of thousands of charge cycles. In contrast, an iPhone battery usually begins to wear out after only 300-400 cycles, after which it can only hold 80 percent of its original, full-capacity charge.
Thai’s Ph.D project focused on studying how nanowires break down over cycles in lithium batteries. The nanowires that Thai uses are even thinner than a strand of human hair. These nanowires can hold a charge far better than normal wires, which is why there is such a focus on using them to create more efficient and longer-lasting batteries. Unfortunately, the biggest weakness of these wires is that they are fragile and prone to brittleness after enough charge cycles in a battery, making them impractical for long-term use and repeated recharging.
Typically, the nanowires tested at the lab would be almost completely useless after around 6000 charge cycles, or even 7000 cycles in a best-case scenario. However, while trying to create a solid-state version of a nanowire battery — a battery with both solid conductors and electrodes — Thai decided to coat a gold nanowire in a stiff, gel electrolyte solution instead of the liquid electrolyte solution normally used in order to have a solid-to-solid connection. Then she began testing the battery for a multitude of things, including the number of charge and discharge cycles.
Thai soon realized that, even after twelve thousand cycles of this, there was no change in the wire’s efficiency and charge capacity, as the gel appeared to help protect and hold the shape of the wires with every charge.
“I expected the cycling to be better, but I didn’t [expect] it to last … much longer,” said Thai. “It’s a beyond expected phenomenon, and a very exciting [find].”
The discovery was completely accidental, but it opens up a myriad of opportunities for batteries of the future. While the lab has not actually created a commercial use battery that the public can use, it has definitely made the possibility of buyable nanowire batteries far more likely. This discovery is essentially a proof-of-concept for public nanowire batteries, and shows that something like it can actually be accomplished.
If this nanowire technology can ever go into normal, everyday rechargable batteries, not only could phones in the near future have batteries that wouldn’t worsen over their lifetime, but the batteries could also hold a longer charge in general. On a larger scale, the same could even be applied to having ultra-efficient batteries in spacecraft in the future.
Thai has since shifted her project focus to this endeavor, and she “is excited to see [her] work looked on with such enthusiasm.”