An illumination-assisted supercapacitor of rice-like CuO nanosheet coated flexible carbon fiber

Abstract

It is of great significance to investigate impact of environment on energy storage and its potential mechanisms. Herein, we designed and synthesized rice-like CuO structure loaded on carbon fibers (CFs) for illumination-assisted supercapacitor. Then we used the CuO/CF as a supercapacitor electrode material, which could effectively reach a photocurrent of 5.05 mAg−1 in 90 mWcm−2, as well as increase capacitance by 2.03 times under illumination. The enhancement mechanism was further analyzed: (Ⅰ) holes and electrons was generated when CuO/CF electrode was stimulated by illumination; (Ⅱ) the excited holes-electrons promoted interface reaction process. Further, this enhancement mechanism was confirmed through cyclic voltammetry, galvanostatic charge-discharge, photoelectric response, impedance analyses and DFT calculation. Moreover, the CuO/CF electrode exhibited good long-cycle performance of 99.45% after 10000 cycles, and it could be well applied in supercapacitors for improving capacitance. We hope that the illumination-assisted supercapacitor reported in this work may provide an important discovery for next-generation smart energy storage devices.