Investigation of the electrochemical and supercapacitor properties of graphen oxide doped polyaniline (PANI) thin films

Graphene oxide@polyaniline/fluorine doped tin oxide (GO@PANI/FTO) composite electrodes were produced by the electrochemical deposition method. GO was synthesized from graphite powders by the Hummers method. The surface analyses of the electrodes were examined by a scanning electron microscope. The presence of functional groups in the electrodes was investigated by Fourier transform infrared spectroscopy. The energy band structures of the electrodes were determined by performing Mott-Schottky analyses of the electrodes. The energy band gaps of the electrodes were calculated by using ultraviolet-visible spectroscopy measurements and Tauc approximation method. Electrochemical and energy storage properties of electrodes were investigated using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge techniques. The purpose of this thesis is to comprehend how the loading concentration of GO affects the electrochemical and energy storage characteristics of the PANI/FTO electrode. The energy band gaps for the PANI/FTO, GO1@PANI/FTO, GO2@PANI/FTO and GO3@PANI/FTO electrodes were calculated as 2,53, 2,51, 2,50 and 2,49 eV, respectively. The specific capacitance of the pure PANI/FTO electrode is 158 F g-1, the specific energy is 18,2 W h kg-1, and the specific power is 118,8 W kg-1 at a current density of 0,3 A g-1. Depending on the GO doping content, the specific energies at 2,0 A g-1 for pure PANI/FTO and GO@PANI/FTO range between 11,4 and 23,1 Wh kg-1, while the corresponding specific power values are between 773,6 and 857,8 W kg-1. Capacitance retention values obtained after 5000 charge-discharge cycles are 62%, 63%, 77% and 84% for the pure PANI/FTO, GO1@PANI/FTO, GO2@PANI/FTO andGO3@PANI/FTO, respectively.