Synthesis and electrochemical performance evaluation of a thermally reduced ZnO@V2O5 binary nanocomposite for supercapacitor applications

Abstract

Developing electrode materials that simultaneously exhibit good electrical conductivity and high electrochemical activity remains a primary concern for high-performance supercapacitors. To address this, we have synthesised a ZnO@V₂O₅ based binary nanocomposite. The composite was synthesised through a simple solid-state method by thermally reducing the oxides, which enables effective integration of ZnO and V₂O₅ at the nanoscale level. The morphological study showed a well-built composite structure that helps ions move through short pathways for faster transport, while the structural and phase examination verified the development of crystalline ZnO and V₂O₅ within the composite. Galvanostatic charge–discharge measurements and cyclic voltammetry were employed to evaluate the electrochemical performance of the synthesised electrode in 2 M KOH electrolyte. The ZnO@ V₂O₅ electrode was found to exhibit stable charge–discharge characteristics with good rate capabilities at a varying current of 2–10 mA. Also, the cyclic voltammetry measurements revealed an overall specific capacitance of 80 F g⁻¹ at a scan rate of 10 mV s⁻¹, demonstrating effective charge storage behaviour. The current contributions were analysed and found to be predominantly diffusion-controlled, suggesting that Faradaic ion intercalation is the principal and dominating charge storage mechanism in the nanocomposite. Overall, the ZnO@V₂O₅ nanocomposite is considered a promising electrode material for supercapacitor applications.