Stretchable, twistable battery for future wearable devices

Batteries have always been a barrier in the evolution and adoption in soft, wearable devices. You wouldn't want the chemicals inside batteries to leak out onto your skin and ideally there wouldn't be a big risk of them bursting into flames either. Stanford engineers have developed a new kind of solid polymer battery that can stretch without breaking and doesn't contain liquid or gel that might seep out and ignite. From Stanford Engineering:

"Until now we haven't had a power source that could stretch and bend the way our bodies do, so that we can design electronics that people can comfortably wear," said chemical engineer Zhenan Bao, who teamed up with materials scientist Yi Cui to develop the device they describe in the Nov. 26 edition of Nature Communications….

The prototype is thumbnail-sized and stores roughly half as much energy, ounce for ounce, as a comparably sized conventional battery. Graduate student David Mackanic said the team is working to increase the stretchable battery's energy density, build larger versions of the device and run future experiments to demonstrate its performance outside the lab. One potential application for such a device would be to power stretchable sensors designed to stick to the skin to monitor heart rate and other vital signs as part of the BodyNet wearable technology being developed in Bao's lab.

More: Decoupling of mechanical properties and ionic conductivity in supramolecular lithium ion conductors (Nature Communications)