Nanofiber supercapacitor device applications of graphene oxide/polypyrrole/polyvinyl alcohol nanocomposite and their derivatives

In this study, it was preferred to use nanofiber structures as electrodes for supercapacitors to reach large surface areas and high specific capacitance values. These nanofiber structures were produced by electrospinning method, which is the most effective method for the production of polymer-based nanofibers. In this method, the prepared composite material is placed a syringe and applied to 25 kV voltage to fabricate carbon based nanofiber structures. The composite drop at the tip of the syringe in the feeder unit is found spherically up to a critical voltage value. As soon as the potential difference applied reaches a threshold value, the composite drop takes the form of a cone, and with a very small increase in voltage, a jet burst from the cone tip. In this jet, it follows different paths towards the collector plate placed a certain distance away from the feeding unit and its composite nanofiber structures are obtained. GO, rGO, PPy, GO/PPy/CB, rGO/PPy/CB, GO/PPy/PVA, rGO/PPy/PVA, GO/PPy/PVA/CB, rGO/PPy/PVA/CB materials have been successfully synthesized and characterized by thermogravimetric analysis (TGA-DTA), BET surface analysis, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), atomic force microscopy (AFM) and solid state conductivity. In addition, circuit model analysis have been performed to understand circuit parameters. The composite materials have been tested in the two electrode system in 1 M H2SO4 solution via three different methods: Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). Furthermore, the specific capacitance (Csp), energy and power densities, capacitance retention values after long-term stability tests of supercapacitor devices were reported in this thesis. Keywords: Nanofiber, Supercapacitor, Electrospinning, Conductive polymer, Graphene