Electrochemical performance of Co₃O₄/Ag/CuO electrodes for supercapacitor applications

This paper presents an exploration of hierarchically bimetallic/trimetallic nanoporous metal oxide-based composite materials such as Co₃O₄/Ag and Co₃O₄/Ag/CuO via the sol-gel route and characterized by several spectroscopic techniques. Electrochemical tests are carried out to assess the supercapacitor performance viz. cyclic voltammetry (CV), galvanostatic discharge/charge (GCD), and electrochemical impedance spectroscopy (EIS). Because of the Faradaic type of capacitance, involving the redox process, Co₃O₄/Ag and Co₃O₄/Ag/CuO modified glassy carbon electrode (GCE) displayed pseudo-capacitance behavior. Moreover, the presence of a nanoporous CuO network enhanced the specific capacitance C_sp of the Co₃O₄/Ag/CuO electrode. Herein, two different electrolytes, Potassium Chloride (KCl) and Sodium Hydroxide (NaOH) are employed to investigate the effect of electrolytes on the electrochemical performance of these materials. Electrochemical measurements revealed the maximum C_sp of 189.29.00 Fg⁻¹ for Co₃O₄/Ag-GCE and 1697.67 Fg⁻¹ for Co₃O₄/Ag/CuO-GCE using GCD studies at a current density (CD) of 0.8 Ag⁻¹. The Co₃O₄/Ag/CuO-GCE showed an admirable energy density (ED) of 99.62 WhKg⁻¹ and power density (PD) of 14.34 kWkg⁻¹. Furthermore, the Co₃O₄/Ag/CuO-GCE displayed excellent cycling stability (over 10,000 cycles) and robust rate capability.