Advanced electrochemical energy storage supercapacitors based on the flexible carbon fiber fabric-coated with uniform coral-like MnO₂structured electrodes

The novel and efficient electrode materials have been developed for supercapacitor applications based on carbon fiber fabric/MnO₂hybrid materials, in which MnO₂was uniformly coated on the surface of carbon fiber fabric (CFF). A green hybrothermal method was used to functionalize CFF with coral-like MnO₂nanostructures to improve the pseudocapacitance properties of the hybrid composites. These CFF/MnO₂composites are used as excellent flexible electrodes for high-performance electrochemical supercapacitors applications. The morphological, structural and crystalline properties of composites were analysed by using various techniques such as FE-SEM, XRD, XPS, and Raman spectroscopy, respectively. The electrochemical performance was examined by cyclic voltammetry (CV), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS). In a three-electrode system, the CV tests reveal the superior specific capacitance of 467 F/g at a current density of 1 A/g with capacitance retention of 99.7% and the columbic efficiency remains as high as 99.3% after 5000 cycles, demonstrating an outstanding electrochemical cyclic stability. In addition, high-performance device fabricated with CFF/MnO₂demonstrated excellent energy density of 20 W h/kg at a power density of 0.175 kW h/kg. These novel electrode materials could be potential candidate for applications in practical and large-scale energy storage systems.