All-in-One\nCompact Architecture toward Wearable All-Solid-State, High-Volumetric-Energy-Density\nSupercapacitors

Abstract

High-performance\nflexible energy storage devices are an important prerequisite to the\nutilization of various advanced wearable electronics, such as healthcare\nsensors and smart textiles. In this work, we design a wearable all-solid-state,\nall-in-one asymmetric supercapacitor by integrating current collectors,\na separator, and negative and positive electrodes into a thin, flexible,\nand porous polyamide nanofiber film. The positive and negative electrodes\nare, respectively, electrodeposited onto each side of the carbon nanotube-modified\nporous polyamide nanofiber film to form the integrated and compact\nasymmetric cell. The all-in-one thin-film asymmetric supercapacitor\nis binder-, additive-, and metal current collector-free, which can\neffectively decrease the cost, simplify the assembly procedures, and\nincrease the energy density. The assembled flexible all-in-one asymmetric\nsupercapacitor with a compact structure shows high gravimetric and\nvolumetric specific capacitances of 70 F g^–1 and\n3.1 F cm^–3 under a current density of 0.5 A g^–1 in a neutral polyvinyl alcohol/LiCl gel electrolyte,\nrespectively. Additionally, the all-in-one asymmetric cell displays\na favorable volumetric energy density of 1.1 W h L^–3, which is among the highest compared with other reported flexible\nsolid-state supercapacitors. Notably, multiple cell units can be integrated\nin one piece of polyamide nanofiber film and connected in series to\nsatisfy the need of high output voltage.