Effect of Concentration Variation on Nickel Cobalt Metal–Organic Framework-Based Electrode Material in Supercapacitor Application

Metal–organic frameworks (MOF) are attracting significant interest as new electrode materials for energy storage applications because of their large specific surface area, porosity, composition, and excellent functionality. Herein, using terephthalic acid as the linker and Ni and Co as the metal centers, a bimetallic metal–organic framework (Ni:Co MOFs = 1:1 2:1 3:1 4:0 0:1) with porous structure was synthesized by the hydrothermal method. The resulting MOFs maintain a flake-like morphology with a high surface area (67.46 m/g), and the pore size of the NCM 2:1 is concentrated to 2–5 nm, which is close to the ideal ion transport channel of electrochemical performance which is suitable for supercapacitor applications. The capacitance of the Ni-Co MOF reached 1385 F/g at 4 mA/cm, and 88.4% capacity was maintained after 3000 cycles, indicating better electrochemical stability. An energy density of 7.8 Wh/kg can be achieved at a power density of 173.07 W/kg and 3.65 Wh/kg is maintained even at a high power density of 692.30 W/kg. These results demonstrate that these Ni-Co MOF bimetallic flakes have great potential as new electrode materials for supercapacitors. Graphical Abstract: [Figure not available: see fulltext.]