Focused Solar-Induced Construction of Activated Solar Carbon@Carbon Fiber Coaxial Electrode from Waste Carbon Fiber-Reinforced Polymer and Its Supercapacitor Performance

Carbon layer-coated μm-sized carbon fiber has the potential to be developed as an electrode, as it can be directly used as an electrode without any preparation process in the absence of an insulating binder. In our work, a carbon layer-coated carbon fiber (C@CF) coaxial structure is constructed by in situ conversion of the epoxy resin around the carbon fiber into a carbon layer, in which a sandwich scaffold of cover/CFRP/screen is designed and adopted. The activated SC@CF, i.e., A-SC@CF, can be directly served as the electrode, and has excellent supercapacitor performance: a high specific capacity of 227.1 F g^-1 at 0.5 A g^-1, with a capacitance retention of 98.9% after 20,000 cycles for the electrode, and an energy density of 16.68 Wh kg^-1 at the power density of 1400 W kg^-1 for its symmetrical supercapacitor (SSC).