Cobalt Phosphide Nanowire Arrays for Flexible Solid-State Asymmetric Supercapacitors*

Supercapacitors, owing to its fast charge-discharge rate, high power density, excellent stability and long cycle life, have received tremendous interest as promising electrochemical energy storage devices for a large variety of applications. In this study, Cobalt phosphide nanowire arrays on carbon cloth were synthesized by a simple two-step hydrothermal method. Owing to the unique nanostructures, it exhibits good performance such as high capacitance and high rate capability when utilized as supercapacitor electrodes. Moreover, the solid-state flexible asymmetric supercapacitor based on cobalt phosphide electrode demonstrates excellent performance such as high energy density and power density. In addition, the solid-state supercapacitor devices show remarkable cycle stability. This work demonstrates an example of cobalt phosphide for supercapacitor electrode application as well as a promising candidate for next-generation energy storage material.