Electrochemical properties of Cu_xCo_1-xFe₂O₄ nanoparticles via cationic substitution for supercapacitor applications

This study presents the synthesis of Cu_xCo_1-xFe₂O₄ nanoparticles as potential supercapacitor electrode materials via a sol–gel auto-combustion process. The electrochemical properties were systematically evaluated as Cu was gradually substituted with Co. Using 1 M KOH electrolyte, we characterized the electrochemical performance of Cu_xCo_1-xFe₂O₄ through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). Among the compositions, Cu_0.5Co_0.5Fe₂O₄ spinel ferrite nanoparticles demonstrated an impressive specific capacitance of 1755 F/g at a current density of 5 mA/cm², along with a power density of 320 W/kg and an energy density of 38.40 Wh/kg. Additionally, the supercapacitor showcased remarkable cycling stability, retaining over 88.60% of its initial capacitance after 5000 GCD cycles. These findings suggest that Cu_xCo_1-xFe₂O₄ is a highly promising candidate for supercapacitor applications.