Fabrication of Ni-foam-assisted graphene@MnO2-doped carbon fabric electrodes from waste cotton fabrics for supercapacitors

Abstract

This study aims to enhance the energy storage capabilities of flexible supercapacitors by fabricating graphene-doped MnO₂-coated carbon cloth electrodes through a hydrothermal method. This technique was selected for its ability to uniformly disperse MnO₂ nanorods (~ 50 nm thick) on carbon surfaces, while anchoring graphene plates at rod interfaces to improve conductivity. Comprehensive characterization including XRD, FTIR, SEM, and TEM confirmed the structural integrity of the electrodes. Electrochemical analysis (CV, GCD, and EIS) revealed a diffusion-controlled charge storage mechanism, achieving a specific capacitance of 513 F/g (205 F/cm³–1027 mF/cm²) at a current density of 1 A/g. The electrodes demonstrated impressive energy-power densities of 45.6 Wh/kg–200 W/kg and retained 87% of their initial capacity after 2500 cycles, indicating robust cyclic stability. Remarkably, the inclusion of graphene enhanced the performance nearly threefold compared to similar electrodes in the literature, making these materials highly promising candidates for next-generation supercapacitors.