High Voltage Output/Energy Density Flexible Asymmetric Fiber Supercapacitors Based on Tree-Like Topology

Abstract

Fiber supercapacitors have attracted significant attention owing to the relevancy in textile electronics. However, the key challenge is to achieve a high output voltage and performance in fiber supercapacitors, while maintaining the high flexibility as fibers. Here, we present a particular type of fiber supercapacitors, based on an overlaid tree topological configuration, by braiding sub-fiber supercapacitor units in an asymmetrical series connection. The tree-like topology-based asymmetric fiber supercapacitors (TTAFSCs) simultaneously achieved a high energy density (22 mWh cm-3 at a power density of 444 mW cm-3) and voltage output, while maintaining outstanding mechanical properties (>1000 bending cycles, capable of loading an object of ~200 g). By continuous braiding of a 6-unit TTAFSC (28 cm length), we were able to achieve a tunable output voltage as high as 9.6 V, which is superior to that achieved by most state-of-the-art fiber supercapacitors. Furthermore, TTAFSCs of ~8 cm long are capable of lightening light-emitting diodes, driving a watch, and powering a display, even at the bent and twisted state. The design of TTAFSCs and fabrication technology acquired represent a genuine breakthrough in textile electronics.