Stretchable soft batteries: From structures to materials

Flexible electronics, characterized by their portability, lightweight, and biocompatibility, have significantly innovated diverse fields. The pursuit of soft robotics, conformal wearable devices, and implantable flexible electronics necessitate power sources with desirable stretchability. To push forward further advancements along the direction, this review is dedicated to presenting an overview of stretchable soft batteries, particularly from both structural and material perspectives. We first introduce the unique roles of stretchable soft batteries in electronic skins, digital healthcare, wearable electronics, and flexible displays; briefly outline the structures that enable stretchability, and summarize the key characteristics of stretchable soft materials, including elastomers, liquids, and gels. We then interpret stretchable batteries based on these materials. Finally, we address the challenges and prospects of innovating structures and materials in developing stretchable soft batteries. This review is expected to serve as a comprehensive guide for the coming research on soft batteries.