Electrochemical Study of Crednerite CuMnO2 for Symmetric Supercapacitor Applications

Abstract

Supercapacitors are gaining prominence as a sustainable energy storage technology due to their quick charge-discharge process, high theoretical capacitance, and extended lifespan. Transition metal oxides (TMOs), particularly the copper-based delafossites CuMO2 (M: Mn, Fe, Cr, Co, Al, Ni), have sparked interest due to their layered structure and multiple oxidation states; however, optimizing their structure and electrochemical performance still presents a challenge. In this work, we represent a cost-effective and low-temperature hydrothermal method for the synthesis of CuMnO2 nanostructures. The material exhibits a monoclinic structure with C2/m space group symmetry as confirmed by X-ray Diffraction (XRD) analysis. Field emission scanning electron microscopy (FE-SEM) revealed a hexagonal and rod-like structure, while Energy Dispersive X-ray analysis confirmed the presence of Cu, Mn, and O in the material. X-ray Photoelectron Spectroscopy validates the oxidation states of Cu and Mn. The CuMnO₂ demonstrated a maximum specific capacitance of 451 F/g at a current density of 0.3 A/g in a three-electrode arrangement with an energy density of 30.7 Wh/kg. The electrode also maintains good cycling stability, while retaining 81% of its initial capacitance after 3000 cycles. The symmetric supercapacitor demonstrates a high specific capacitance of 175 F/g at a current density of 0.5 A/g, an energy density of 15.5 Wh/kg, and maintains 71% cyclic stability even after 5000 cycles.