Flexible lithium-ion battery developed using kirigami

Japanese art technique could push forward wearable technology

Previous smart watch designs have been considered bulky due to rigid and sizeable batteries

A stretchable battery based on the Japanese art of kirigami could push forward developments in wearable technology such as smartwatches, say researchers.

The flexible lithium-ion battery (LIB) extends to over 150% of its original size while maintaining its function and can be easily integrated into a stretchy wrist band.

The team of developers at Arizona State University believe their design could be used to replace rigid and bulky batteries which have limited the development of compact wearable devices.

Their prototype battery was sewn into an elastic band attached to a smartwatch and shown to power it while being stretched away from the wrist.

A number of approaches have previously been used in an attempt to develop flexible and stretchable energy storage devices but the technique of kirigami, a variation of origami that uses a combination of folding and cutting, produced patterns that stretch to over 150% of their original length.

A report by Hanqing Jiang, published in Scientific Reports, said: "The kirigami-based methodology can be readily expanded to other applications to develop highly stretchable devices and thus deeply and broadly impact the field of stretchable and wearable electronics.

"Other applications may include smart bracelets and smart headbands among many others.

"It is expected that the kirigami LIBs are able to resolve one of the bottlenecks in the development of wearable devices by providing a scalable solution for a stretchable energy source to profoundly change the form factor."