Researchers added a compound made of phosphorus and sulfur elements to the electrolyte liquid that carries electrical charge within batteries. This reacts with a lithium metal electrode in an already assembled battery to spontaneously coat it with an extremely thin protective layer. This prevents the growth of dendrites that can cause short circuits and fires, and also prevents corrosion of the lithium metal electrode, allowing the higher energy density.
“We wanted a simple, scalable way to protect the lithium metal,” said Quanquan Pang, who led the research while he was a PhD candidate in chemistry at Waterloo and is now a post-doctoral fellow at the Massachusetts Institute of Technology. “With this solution, we just add the compound and it works by itself.”
The increased storage capacity, or energy density, could boost the distance electric vehicles are able to travel on a single charge, from about 200km to 600km. “This will mean cheap, safe, long-lasting batteries that give people much more range in their electric vehicles,” he said.