Unveiling the temperature-induced structural evolution and electrochemical performance of Co3V2O8 nanostructures

The nanostructured cobalt vanadate (Co 3 V 2 O 8 ) has attracted much interest in energy storage research due to its high energy storage capability and excellent electrochemical activity. This work deals with the capacitive behavior of hydrothermally prepared Co 3 V 2 O 8 nanostructures (NSs) at various calcination temperatures (500 °C to 800 °C) for energy conversion and storage phenomena. The crystal structure, various functional groups, stretching/bending vibrations, surface morphology , and the different oxidation states in the Co 3 V 2 O 8 NSs were examined using different physicochemical techniques. Herein, we have discussed the prepared material for water-splitting (WS) and supercapacitors (SCs) applications using two and three-electrode cell systems in the 1 M KOH electrolyte. Among all the samples, the CVO-3 shows a homogeneous distribution of nanospheres , with a suitable overpotential of 148 mV for oxygen evolution reaction (OER) and 132 mV for hydrogen evolution reaction (HER) at 10 mA/cm 2 , exhibiting better long-term stability. Additionally, the optimized electrode was utilized using a two-electrode cell system for electrocatalytic measurements, and the process was carried out at 1.54 V and 1.65 V at 10 mA/cm 2 and 100 mA/cm 2 , and it shows superior electrocatalytic measurements. In addition, the CVO-3 electrode shows better electrochemical properties , including a high specific capacitance (C s ) of 829 F/g at 5 mA/cm 2 and excellent stability of 91.18 % over 10,000 cycles. The fabricated hybrid device demonstrates a maximum energy (E d ) and power densities (P d ) of 21 Wh/kg and 3750 W/kg with maximum stability over 5000 cycles. Therefore, the prepared Co 3 V 2 O 8 NSs (CVO-3) can be used as a promising electrode material for energy conversion and storage applications. • The effect of calcination temperature on Co 3 V 2 O 8 NSs is studied for WS and SCs. • The interconnected nanosphere-like morphology was observed for CVO-NSs material. • The CVO-3 electrode shows less overpotential and Tafel slope with good stability. • The CVO-NSs electrolyzer shows a 1.54 V cell voltage for overall water splitting. • The CVO-3 electrode exhibits a specific capacitance of 829 F/g at 5 mA/cm 2 .