Stretchable batteries based on kirigami, a variation of origami, that can stretch to over 150% their original size while maintaining their function are described in Scientific Reports this week. The batteries are shown to power a smart watch and are easily integrated into the stretchy wrist band, demonstrating the potential of these batteries in flexible, wearable devices.

Various approaches have been employed to develop flexible and stretchable energy storage devices, including using the concept of origami to produce foldable batteries. However, origami-based devices are limited to only folding in one plane and form uneven surfaces. These issues are overcome by Hanqing Jiang and colleagues, who design lithium-ion batteries based on the art of kirigami ? a technique that uses a combination of folding and cutting ? to produce patterns that can stretch to over 150% their original length. Their prototype battery was sewn into an elastic band attached to a smart watch, and was shown to power the watch while being stretched. The authors suggest that this type of battery could potentially be used to replace rigid and bulky batteries that may have limited the development of compact wearable devices.