CuCo-Based Mixed Metal–Organic Framework: A Blueprint for Achieving High Specific Capacitance in Supercapacitors

The rational design of metal–organic frameworks (MOFs) with controlled composition provides a versatile route for developing high-performance electrode materials for supercapacitors. In this study, a bimetallic CuCo-MOF is synthesized via a one-step solvothermal process using trimesic acid as an organic linker, enabling uniform incorporation of Cu and Co metal centers within the framework. Structural and morphological characterizations using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) confirm the successful formation and homogeneity of the composite structure. Electrochemical evaluations in 3 M KOH, including cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS), reveal that the CuCo-MOF electrode delivers a high specific capacitance of 1578 F g⁻¹, significantly surpassing the single-metal Cu-MOF (522 F g⁻¹) and Co-MOF (592 F g⁻¹) counterparts. The electrode exhibits remarkable cycling stability with 87.8% capacitance retention after 4000 cycles and a consistent Coulombic efficiency of 92.8%. Furthermore, an asymmetric supercapacitor (ASC) device employing CuCo-MOF as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 28 Wh kg⁻¹ at a power density of 700 W kg⁻¹, while maintaining 83.9% capacitance retention over 3000 cycles. These results demonstrate that the CuCo-MOF possesses superior electrochemical activity, stability, and scalability, underscoring its strong potential as a next-generation electrode material for advanced energy storage systems.