Structural insights and electrochemical behavior of Co21.2O32 and Cu2CoO3for high-performance supercapacitor applications

Abstract

This study delves the structural, morphological, and electrochemical properties of Co_21.2O₃₂and Cu₂CoO₃ compounds for supercapacitor applications. X-ray diffraction (XRD) confirms the pure crystalline structures of Co_21.2O₃₂ (cubic, Fd-3m) and Cu₂CoO₃ (orthorhombic, Pmmn), with crystallite sizes of 35.925 nm and 29.518 nm, respectively. Field emission scanning electron microscopy (FESEM) reveals granular morphologies with average grain sizes of 559.67 nm for Co_21.2O₃₂and 676.98 nm for Cu₂CoO₃. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) confirm the elemental compositions and valence states, including the presence of oxygen vacancies that enhance electron hopping. Electrochemical analysis, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), shows that Cu₂CoO₃ exhibits superior performance, with higher specific capacitance (1186 F g⁻¹ at 1 A/g) and excellent cycling stability (85 % retention after 10,000 cycles). The addition of copper improves conductivity, charge storage, and long-term durability, making Cu₂CoO₃ a promising candidate for energy storage applications.