Researchers from Stanford University have created a soft and stretchable battery that in the future could power next-generation wearables.
The battery relies on a special type of plastic to store power more safely than flammable formulations used in conventional batteries.
"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 Zhenan Bao, a chemical engineer at Stanford University.
While the use of plastics in batteries is not new, previously they have been used as electrolytes or the energy source that transports negative ions to the battery’s positive pole. However, those polymer electrolytes have been flowable gels that could potentially leak or even burst into flames.
Instead, Stanford researchers developed a polymer that is solid and stretchable rather than gooey and that could potentially leak, yet still carries an electric charge between the battery’s poles. When testing the battery, it was able to maintain a constant power output when squeezed, folded or stretched to nearly twice its original length.
The prototype battery is about the size of a thumbnail and stores about half as much energy as a conventional battery.
The stretchable battery could enable a new type of wearable that forms around a wrist or works as electronic skin. Another potential application could be a device that can power stretchable sensors that stick to the skin to monitor heart rate and other vital signs as a wearable.
The next steps include working to increase the stretchable battery’s energy density, build larger versions of the device and run future experiments to demonstrate the performance outside of a lab.
The full research can be found in the journal Nature Communications.