Electrophoretic Fabrication of ZnO/CuO and ZnO/CuO/rGO Heterostructures-based Thin Films as Environmental Benign Flexible Electrode for Supercapacitor

Sustainable fabrication of flexible hybrid supercapacitor electrodes is extensively investigated during the current era to solve global energy problems. Herein, we used a cost-effective and efficient electrophoretic deposition (EPD) approach to fabricate a hybrid supercapacitor electrode. ZnO/CuO and ZnO/CuO/rGO heterostructure were prepared by sol-gel synthesis route and were electrophoretically deposited on indium tin oxide (ITO) substrate as a thin uniform layer using 1 V for 20 min at 50 mV/s. ZnO/CuO and ZnO/CuO/rGO heterostructure coated ITOs were then employed as the working electrode in a three-electrode setup for supercapacitor measurements. The fabricated electrodes have been investigated by Galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) to study their charge storage properties. ZnO/CuO revealed a specific capacitance of 1945 F g^-1 at 2 mV/s and 999 F g^-1 at 5 A g^-1. However, an increased specific capacitance of 2305 F g^-1 was measured for ZnO/CuO/rGO heterostructure at 2 mV/s and 1235 F g^-1 at 5 A g^-1. The lower internal resistance was observed for ZnO/CuO/rGO heterostructure, indicating good conductivity of the electrode material. Thus, the overall results of the current study suggest that EPD-assisted ZnO/CuO/rGO heterostructure hybrid electrode possess a substantial potential for energy storage as a supercapacitor.