From light-up shoes to smart watches, wearable electronics are gaining traction among consumers, but these gadgets' versatility is still held back by the stiff, short-lived batteries that are required. These limitations, however, could soon be overcome. In the journal ACS Nano, scientists report the first durable, flexible cloth that harnesses human motion to generate energy. It can also self-charge batteries or supercapacitors without an external power source and make new commercial and medical applications possible.