The transition metal-based organometallic compounds show more advantages, such as good redox mechanism, good chemical stability, and low oxidation potential over the transition metal oxides, sulfides, and hydroxides. The electrochemical performance of the transition metal organometallic compound can be modified by modifying the functional groups on the ligands surrounding the transition metal. In this work, we synthesized the cobalt-iron-hydroxyquinolinate (CFH) through the solvothermal method. The reduced graphene oxide (RGO) is incorporated into the CFH to enhance the electrical conductivity, which improves the electrochemical performance. The cobalt-iron-hydroxyquinolinate incorporated RGO (CFHR) was electrochemically evaluated by the cyclic voltammetry, charge-discharge analysis, electrochemical impedance spectroscopy analysis, and distribution relaxation time analysis (DRT). It shows the higher specific capacity of CFHR (1076 mF cm-2) than CFH (631 mF cm-2) by adding RGO to the CFH at 1 mA cm-2. The diffusion coefficient is calculated from the EIS analysis. Dunn's analysis was used to study the capacitive and diffusive contributions of the CFH and CFHR. The DRT analysis elaborates the mechanism involved in the electrochemical process. The systematic electrochemical analysis resulted in the CFHR can be a good electrode material for the hybrid supercapacitor applications.
Lishavi et al. (Wed,) studied this question.