Revealing high-performance supercapacitor: Synergistic cobalt sulfide/reduced graphene oxide nanocomposite for enhanced energy storage

Abstract

Transition metal sulfide-based electrodes are crucial for energy storage due to their straightforward synthesis, fast redox switching, and high conductivity. The cobalt sulfide/reduced graphene oxide (Co₃S₄/rGO) nanocomposite is prepared using a single-step hydrothermal process, analysed by X-ray diffraction, Raman spectroscopy, and Electron microscopy, which verifies its crystalline structure and effective integration. X-ray photoelectron spectroscopy confirms the chemical composition and Brunauer-Emmett-Teller analysis measures surface area and pore size distribution. In a three-electrode system, Co₃S₄ delivers a specific capacitance of 815 F/g, while Co₃S₄/rGO achieves 1560 F/g at 1 A/g, attributed to a synergistic effect, with 89% retention over 5000 cycles at 6 A/g. As a two-electrode asymmetric supercapacitor, it delivers 113 F/g at 1 A/g, with an energy density of 40.2 Wh/kg and a power density of 804 W/kg, maintaining 82% stability over 12,000 cycles at 6 A/g, showcasing its potential for supercapacitors applications.