Abstract
The spread of wearable and flexible electronics devices has been accelerating in recent years for a wide range of applications. Development of an appropriate flexible power source to operate these flexible devices is a key challenge. Supercapacitors are attractive for powering portable lightweight consumer devices due to their long cycle stability, fast charge-discharge cycle, outstanding power density, wide operating temperatures and safety. Much effort has been devoted to ensure high mechanical and electrochemical stability upon bending, folding or stretching and to develop flexible electrodes, substrates and overall geometrically-flexible structures. Supercapacitors have attracted considerable attention and shown many applications on various scales. In this review, we focus on flexible structural design under six categories: paper-like, textile-like, wire-like, origami, biomimetics based design and micro-supercapacitors. Finally, we present our perspective of flexible supercapacitors and emphasize current technical difficulties to stimulate further research.