Bimetallic Co3V2O8 microstructure: A versatile bifunctional electrode for supercapacitor and electrocatalysis applications

Abstract

Our research focuses on hydrothermally synthesizing a bimetallic cobalt vanadium oxide Co3V2O8 (CVO) microstructure, tailoring it for use in both bifunctional supercapacitor and electrolysis applications. We carefully optimized the molar ratio of Co and V to achieve a hexagonal microstructure for Co3V2O8, confirming it through field emission scanning electron microscopy (FESEM) and High resolution transmission electron microscopy (HRTEM) studies. The optimized electrode exhibited exceptional electrochemical characteristics when utilized in a supercapacitor application. It demonstrated a superior areal capacitance of 3.76 F/cm2 at a current density of 1 mA/cm2. Subsequently, we utilized the optimized electrode in an asymmetric supercapacitor configuration with activated carbon (AC), resulting in an areal capacitance of 126.1 mF/cm2 and an energy density of 29.6 mWh/cm2 at a power density of 2.6 W/cm2. To assess the stability of this configuration, we conducted 5000 cycles at 5 mA/cm2 and observed a retention rate of 87%. Additionally, we investigated the effectiveness of the optimized electrode as an electrocatalyst for water oxidation in a 1 M KOH electrolyte. In this setup, the CVO-4 electrode exhibited a lower overpotential of 226 mV for the hydrogen evolution reaction (HER) and a Tafel slope of 178 mV/dec for HER. Overall, our findings indicate that the as-prepared optimized electrode operates highly efficiently in bifunctional applications, positioning it as a promising candidate for energy conversion and storage operations.