Synthesis and electrochemical characterization of nanostructured Ni-Co-MOF/graphene oxide composites as capacitor electrodes

A metal organic framework with dual metal centers (Ni-Co-MOF) was directly grown on graphene oxide sheets (Ni-Co-MOF/GO) via a one-pot solvothermal reaction and used as a hybrid supercapacitor electrode. Synthesis of the composite employs water as an environmentally friendly solvent and 2-methylimidazole as an inexpensive organic ligand. Ni-Co-MOF/GO with a 3D structure possesses features that provide a large specific surface area, a stable interface between the electrolyte and electrodes, and better charge transfer path. The synergistic effects of mixing cobalt and nickel and the electrochemical behaviors of the graphene oxide content on the mixed metal organic framework were investigated. Ni-Co-MOF/GO 2 (amount of graphene oxide, 0.2 g) showed the highest energy storage performance. At a current density of 1 A g⁻¹, the maximum specific capacitance was 447.2 F g⁻¹, with excellent rate capability. Evaluation result of the cycle characteristics of Ni-Co-MOF/GO 2 showed outstanding life stability of 99.6% after 300 cycles. Based on the performance of the Ni-Co-MOF/GO electrode, this material is expected to pave the way for the development of promising materials, which hold good electrochemical properties for supercapacitors.