Electrochemical Evaluation of Redox Active Cobalt‐Oxyquinolinate Complex Layered on Reduced Graphene Oxide for Hybrid Supercapacitor Application

ABSTRACT The redox active organometallic compounds are the prominent supercapacitor electrode materials due to the attractive properties like stable redox scheme, good electron transfer mediator, and low oxidation potential. The key advantage of the organometallic compounds is that the electronic property of the electrode can be modified by altering and functionalizing the ligands around the metal atom. In this work, we synthesized cobalt‐oxyquinolinate (Co‐Q) organometallic compound by solvothermal method. To improve the electrical conductivity, the reduced graphene oxide (RGO) is grafted on Co‐Q. The electrochemical behaviour of Co‐Q is improved by the addition of RGO. The specific capacitance of Co‐Q layered on RGO is greater (1206 mF cm −2 ) than Co‐Q (670 mF cm −2 ) at current density of 1 mA cm −2 . This is due to the increase in active sites after the incorporation of RGO on Co‐Q; further, this promotes the diffusion process. The fundamental electrochemical analyses, including cyclic voltammetry, galvanostatic charge–discharge analysis, and electrochemical impedance analysis, provided the information about the electrochemical energy storage performance. Dunn's method is used to understand the diffusion and capacitive contributions of the electrode material during energy storage. From the electrochemical analysis, Co‐Q layered on RGO is a suitable material for the energy storage application due to its high diffusion and stability.