Flexible nanofiber web electrode with high surface area and capacitance for electrochemical capacitor

Flexible, lightweight electrode for electrochemical capacitor with high surface area and capacitance was successfully prepared based on the electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber web. Electrode was fabricated by three steps. First, PVDF-HFP nanofiber web was formed by electrospinning. Platinum (Pt) thin layer as a current collector was then deposited on the electrospun PVDF-HFP nanofiber web by an electroless plating and followed by deposition of manganese dioxide (MnO2) using a hydrothermal method, finally producing MnO2/Pt/PVDF-HFP nanofiber web electrode. We confirmed formation of MnO2/Pt/PVDF-HFP nanofiber web electrode with desired structure and chemical composition. The galvanic charge-discharge specific capacitance of the flexible MnO2/Pt/PVDF-HFP nanofiber web electrode was 201.4 F/g at current density of 1 mA/cm2. Even after 1000 bending cycles, specific capacitance obtained from cyclic voltammetry of the nanofiber web electrode maintained up to 88.8% of the initial capacitance, implying excellent bending durability of the electrode. Since MnO2/Pt/PVDF-HFP nanofiber web electrode exhibited excellent electrochemical activity and mechanical flexibility, we expect potential applications in flexible, wearable, and stretchable electronic devices.Graphic abstractScheme of fabrication process and surface and cross-section of MnO2/Pt/PVDF-HFP nanofiber web