Controllable synthesis of composite electrode material to enhance the electrochemical performance of supercapacitors

Abstract

Cobalt oxide (Co3O4), cobalt oxide/reduced graphene oxide (Co3O4/rGO), and cobalt oxide/reduced graphene oxide/polyaniline (Co3O4/rGO/PANI) ternary composites with varying PANI concentrations are created using the hydrothermal route and in-situ polymerization of aniline monomer. X-ray diffractometer XRD results reveal the presence of cubic Co3O4, hexagonal rGO, and emeraldine salt structure of PANI. SEM images reveal dense interconnected PANI fibers and rGO clusters across the quasi-cube-like Co3O4 structure. (Co3O4/rGO)/PANI (80%:20%) composites offer excellent optoelectronic properties with 2.32 eV bandgap. As the concentration of PANI increases, the (Co3O4/rGO)/PANI (40%:60%) exhibits 1673 dielectric constant, making it suitable for various electronics and electrical engineering applications. The electrochemical findings show that the (Co3O4/rGO)/PANI (60%:40%) based electrode has an exceptional capacitance of 3103.27 F/g at 2 A/g, maintaining a capacitance of nearly 92% after 10,000 continuous cycles. The composite also exhibits an extraordinary specific capacitance of 2101.3 F/g at 5 mV/s and the lowest ohmic resistance. These findings support the use of the (Co3O4/rGO)/PANI (60%:40%) ternary composite as a valuable and innovative electrode for supercapacitors.