High voltage output/energy density flexible asymmetric fiber supercapacitors based on a tree-like topology

Fiber supercapacitors have attracted significant attention because of the relevance for textile electronics. However, the key challenge is to achieve high output voltage and performance of fiber supercapacitors while maintaining the high flexibility of the fibers. Here, we present a fiber supercapacitor, based on an overlaid tree topology configuration, by braiding sub-fiber supercapacitor units in an asymmetrical series connection. The tree-like topology-based asymmetric fiber supercapacitors (TTAFSCs) achieve a high energy density (0.022 Wh cm−3 at a power density of 0.444 W cm−3) with an extendable high voltage output (>9.6 V) while maintaining outstanding mechanical properties (>1,000 bending cycles, capable of loading an object of ∼200 g). TTAFSCs of ∼8 cm in length are capable of lighting light-emitting diodes, driving a watch, and powering a display, even in a bent and twisted state.