Enhancing Electrochemical Performance of Super capacitors Electrode Using Nickel-Based Metal-Organic

Metal-organic frameworks (MOFs) have been used as electrode materials in supercapacitors (SCs) due to their high specific surface area and suitable porosity size. However, using single-component MOFs in SCs leads to poor electrical conductivity, insufficient stability, and poor mechanical properties, and thwarts the effect of high capacity and efficient performance. In this paper, to improve the electron transfer rate and take advantage of the specific surface of MOFs, nickel-based metal-organic framework/graphene nanocomposites were prepared by hydrothermal in-situ synthesis, and to prevent agglomeration, graphene (0, 2.5, 5, and 10wt%) was added during the synthesis process. To characterize the structure of the nanocomposites, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) were used. To study the supercapacitor behavior, electrochemical tests, such as cyclic voltammetry, electrochemical impedance, and repeatability behavior were used. The electrode prepared by the nickel-based MOFs in the 6M KOH electrolyte had a specific capacity of 660 F/g, while their composite with graphene had a specific capacity of 1017 F/g. As a result, benefiting from composite properties and increasing electrical conductivity of MOFs with graphene resulted in greater porosity availability and increased total storage capacity.