Preparation and Application of Co3O4/Reduced Graphene Oxide/Ni Foam as High-Performance Asymmetric Supercapacitor Electrodes

Co3O4 nanorods and hybrid reduced graphene oxide (Co3O4/rGO) were synthesized on a Ni foam substrate using affordable and simple hydrothermal synthesis. Then, the structural and morphological investigations of nanoparticles were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) mapping, Raman spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. It was found that rGO increased the surface and short channels for the transfer of ions and electrons. The maximum capacitance of Co3O4/rGO was found to be 2870 F/g, while Co3O4/rGO/NF was observed to have the largest capacitance in the literature. Furthermore, rGO decreased resistance arising from charge and ion transfer by creating shorter channels. Therefore, the superior Co3O4/rGO/NF electrode in the tow-electrode system was investigated for asymmetric supercapacitor purposes. The rGO electrode served as the negative electrode, while the Co3O4/rGO/NF was assumed to be the positive electrode. A discharge time of 144 s led to a capacitance of 148 F/g, a power density of 486 W/kg, and an energy density of 20 Wh/kg.