Lithium ion batteries used in mobile devices might have gotten more powerful, or, in some cases, less flat, but there’s no escaping the fact that, sooner or later, they will lose their life and need to be replaced. But thanks to researchers from Standford University and Tsinghua University in Beijing, that time might come later rather than sooner.
The principle behind this new battery technology is in making sure lithiated silicon materials inside the batteries are able to hold electrons for a longer period of time. Silicon has been used in batteries to allow it to hold more electrons compared to oxides. However, silicon swells up when holding electrons and then shrink back down when discharged. Over time, this causes the silicon materials to crack and break apart, affecting their ability to hold on to electrons.
The key, then, according to Chao Wang from Stanford and Hui Wu of Tsinghua University, is in delaying that last stage by keeping the silicon materials together longer. The researchers used a type of “self-healing” coating that instantly repairs the cracks and pulls back the materials together. Thus, the materials are able to store electrons much longer than conventional batteries that use polymer binders, and thereby prolonging a battery’s life.
That said, this self-healing property doesn’t actually prevent the silicon materials from breaking up in the first place, which will eventually lead to the battery’s death, but in a much longer time. Still, the researchers are hoping to be able to produce batteries that can last up to 500 charge cycles before being replaced.