A team of researchers from Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory has developed a self-healing battery electrode, the first of its kind for lithium ion batteries.

The self-renewing battery contains a silicon electrode that is protected by a stretchy polymer, which not only holds the battery together but also fills in the tiny cracks that may develop during battery operation, essentially allowing the battery to heal itself.

A flexible battery coating is particularly important for batteries with silicon electrodes—which have a high capacity for capturing and storing energy from lithium battery fluid—because silicon electrodes expand and shrink each time the battery charges and discharges. The brittle material that coats these high-capacity batteries therefore cracks and falls apart with use. With a self-healing coating, these batteries can last longer and lose performance less quickly.

The self-healing material—originally developed by third-year postdoctoral researcher Chao Wang in the lab of Zhenan Bao, a professor of chemical engineering at Stanford—breaks easily to accommodate for a growing electrode. Its broken ends quickly bond together again, in a manner similar to the process that allows biological molecules such as DNA to reassemble.