If electric cars are ever to drive hundreds of miles between charges—as they must to compete with gas-powered cars—their batteries will need to store much more energy. Unfortunately, several of the most promising high-capacity battery materials are prone to breaking in ways that would cut an electrified road trip short.

Now researchers at Stanford University have shown that mixing one such promising battery material, silicon microparticles, with self-healing polymers helps prevent a longer-lasting battery from failing. They say the self-healing polymers could stabilize other promising but damage-prone battery materials.

The self-healing battery’s negative electrode, or anode, combines silicon with polymers that act like chemical zippers, healing cracks that form when the battery is used and recharged.