High-capacity batteries could have a huge impact on products ranging from smart phones to electric cars, if only they weren't so prone to fractures and cracks. Now researchers at Stanford have developed a self-healing battery that mends itself on every charge cycle, dramatically extending its life.

Tech Review's Katherine Bourzac explains (emphasis added):

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.

The self-healing battery electrode has so far been tested with pure lithium metal as the positive electrode, because its storage capacity is much greater than that of any conventional cathode. The self-healing electrode itself has eight times the storage capacity of the carbon anodes found in a conventional rechargeable lithium-ion battery. If paired with a conventional cathode, it would create a battery that stored about 40 percent more energy. If paired with a correspondingly high-capacity cathode, total energy storage would be doubled or tripled.

While previous silicon batteries could only be discharged and recharged 10 times before breaking down, the self-healing battery weathers 100 charging cycles. But that's still not enough, acknowledges Stanford materials scientist Yi Cui. "We need to go to 500 cycles for portable electronics, and a few thousand for electric vehicles," Cui says.