The structure design of flexible batteries

Flexible batteries can withstand harsh conditions and complex deformations through effective structure design while maintaining stable electrochemical performance and an intact device during the strain yield process. However, the development of flexible batteries is largely focused on advanced electrodes or electrolytes, and little attention is paid to the structural design. In this perspective, we highlight the structural design strategies and corresponding requirements of flexible batteries for typical flexible electronic devices. Meanwhile, we present a new principle of classification in which almost all flexible structures are divided into three types: an active material area deformation structure, a partially active material area deformation structure, and an inactive material area deformation structure. More importantly, we propose a new equation to comprehensively evaluate the energy density and deformation capability of flexible batteries. We also constructively propound potential research directions and application scenarios in the field of structure design of flexible batteries.