Electrochemical Investigation of V ₂ O ₅ as a High-Performance Material for Supercapacitors and Electrocatalysis

Phase-pure orthorhombic vanadium pentoxide (V2O5) nanostructures synthesized via a solvothermal method are systematically evaluated for their dual functionality in electrochemical energy storage and electrocatalytic water-splitting applications. Electrochemical investigations in three aqueous electrolytes reveal superior supercapacitor performance in alkaline 6 M KOH, achieving the highest areal capacitance of 31 mF cm–2 at 5 mV s–1, energy density of 0.86 μWh cm–2, and power density of 0.8 mW cm–2. The supercapacitor further demonstrates outstanding long-term stability, preserving 95% of its initial capacitance after 10,000 charge–discharge cycles. In addition, the electrochemical performance of the supercapacitor is investigated in acidic H2SO4 electrolyte and neutral Na2SO4 electrolyte. For water-splitting applications in 1 M KOH, V2O5 exhibits promising bifunctional electrocatalytic activity with low overpotentials of 177 mV for the hydrogen evolution reaction and 478 mV for the oxygen evolution reaction at 10 mA cm–2, with a high electrochemically active surface area of 51 cm2 facilitating abundant active sites for catalytic reactions. These findings demonstrate that V2O5 nanostructures represent versatile materials for sustainable energy applications, offering dual functionality as high-performance supercapacitor electrodes and efficient water-splitting electrocatalysts.