A metal-oxide nanofiber-decorated three-dimensional graphene hybrid nanostructured flexible electrode for high-capacity electrochemical capacitors

Abstract

Carbonized polypyrrole-coated SnO₂/Co₃O₄ nanofiber-decorated three-dimensional graphene (CPSC-3rGO) was fabricated using single-nozzle co-electrospinning, freeze-drying, and thermal reduction. Polypyrrole-coated SnO₂/Co₃O₄ nanofibers (PSCNFs) were fabricated using vapor deposition polymerization (VDP) of SnO₂/Co₃O₄ nanofibers. The PSCNFs were then mixed with an aqueous graphene oxide (GO) solution and freeze dried to form a PSCNF-decorated 3D GO (CPSC-3GO) structure. The CPSC-3rGO was produced via thermal reduction to form a hybrid nanomaterial for use as the electrodes of electrochemical capacitors (ECs). The specific capacitance of the CPSC-3rGO was 446 F g⁻¹, which is larger than that of the other 3D nanomaterials investigated (the specific capacitance of PSCNFs was 270 F g⁻¹, that of PSC-3GO was 285 F g⁻¹, and that of 3D rGO was 150 F g⁻¹). In addition, ECs with two symmetrical CPSC-3rGO electrodes were fabricated from two layers of CPSC-3rGO separated by a polymer electrolyte gel and encapsulated in polyethylene terephthalate (PET) membranes. These devices exhibited excellent electrical performance, which was preserved following repeated mechanical deformation.