Sulfur-Modified Co ₃ O ₄ –Graphene Nanocomposites for High-Performance Supercapacitor Applications

The development of high-performance electrode materials is crucial for advancing supercapacitor technology. This work presents a sulfur-doped cobalt oxide-reduced graphene oxide (S-doped Co₃O₄-rGO) nanocomposite directly synthesized on nickel foam via a facile hydrothermal method and subsequent annealing. Comprehensive characterization (XRD, Raman, FTIR, XPS, FE-SEM, and TEM) confirmed successful synthesis and uniform dispersion of components. Electrochemical evaluation revealed exceptional performance: the S-Co₃O₄-rGO electrode achieved a specific capacitance of 856.8 F/g at 2 A/g, significantly surpassing that of pure Co₃O₄ (198.8 F/g) and undoped Co₃O₄-rGO (580 F/g). Furthermore, it demonstrated outstanding long-term stability, retaining 97.5% of its initial capacitance after 5000 charge-discharge cycles at 5 A/g. The synergistic effect between the sulfur-doped graphene network and cobalt oxide nanoparticles is identified as the primary factor enabling this superior capacitance and durability, positioning this nanocomposite as a highly promising candidate for next-generation energy storage devices.