Date:4 November 2016
Snap this self-healing batteries clean in half and like a healing wound it will pull itself back together. Within seconds the battery resumes its delivery of electric current. No harm done.
By William Herkewitz
This fascinating new method to craft autonomously self-healing electronics comes courtesy of a team of engineers led by Amay Bandodkar at the University of California, San Diego. By dispersing micro-sized magnetic particles into conductive materials like graphite, gold, and silver, Bandodkar’s team has developed a suite of electronics that will magnetically heal after a snap or fracture. Bandodkar’s team unveiled their electronics today in the journal Science Advances.
“It’s actually a pretty simple concept,” Bandodkar says. “This started when we asked ourselves, how can we simply implement a self-healing feature into existing electronics without without making them unnecessarily complicated or expensive? This was our solution.”
Bandodkar’s team manufactured and tested several self-healing batteries, sensors, and circuits. The success of all of these devices lies in the recipe for the conductive graphite material used to make them. It’s a simple three-part formula. Bandodkar’s team mixed normal graphite, a inexpensive binding agent, and small magnetic particles made out of “cheap neodymium magnets, the kind you can buy at the supermarket,” he says.
The engineers printed simple electronics with this magnetic mixture. The printing part is not exactly a new advancement, explains Bandodkar. “Printed electronics is already a multi-billion dollar industry, and is growing exponentially,” he says. The key finishing touch was to subject the printed electronic component to a strong electromagnetic field. This process ensured that all the microscopic magnetic particles would align in one direction so they would snap back together in their original orientation once broken.
“One allure of printed electronics is that they’re so cheap,” he says, and the inclusion of the small magnetic particles makes the process only marginally more expensive—”which is great because there’d be no point of making a self-healing system if it was very expensive.”
Although Bandodkar’s simple electronic components self-heal, afterward you can still see where the crack was. In one test, for example, the engineers used scissors to cut through a wearable circuit powering an LED light on a T-shirt sleeve. While the circuit healed, re-powering the LED light, you could see the electronic scar on the graphite circuit.
While Bandodkar’s self-healing breakthrough is cheap and remarkably simple, there is one potential downside. The inclusion of magnetic particles makes Bandodkar’s electronics, well, magnetic. And as anyone who’s ever put a refrigerator magnet on a hard drive knows… that’s not always a good thing for electronic systems.
“We’ve thought about this problem. One way to solve it is by adding layers of electromagnetic shielding materials to whatever you’re building.” We’ll have to see if they figure out a way to do that without adding a ton of cost or weight.
Video credit: Popular Mechanics USA