الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Supercapacitors become an attractive power solution for an increasing number of applications. Different electrodes have been prepared using polyaniline (PANI), reduced graphene oxide (RGO) and RGO-PANI composites. The substrate for these electrodes made of stainless steel (304). Also flexible supercapacitors have been fabricated using polyethelene (PE) coated gold substrate, where active materials are deposited using spray coating method.Proposed supercapacitors are fabricated by assembling two electrodes separated with a piece of filter paper or polymer electrolyte. The PANI is prepared chemichally with hydrochloric acid and ammonium persulfate at room temperature. Graphene oxide (GO) is prepared by modified hummer method. The GO is reduced by hot sodium hydroxide or by hydrazine hydrate. PANI doped with camphor sulfonic acid (CSA), Graphene and RGO-PANI composites with different GO mass ratios are used as active materials for supercapacitor electrodes. The effect of adding particles of RGO on the properties of RGO-PANI composites and reduction time is studied. The crystal structure and the surface topography of all materials are measured by means of UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopy (SEM). Cyclic voltammetry (CV), charge-discharge measurements, electrical impedance spectroscopy (EIS) and a four-point probe device investigate the electrochemical properties of the fabricated supercapacitors. Specific capacitance and energy density are calculated for the fabricated supercapacitors. In addition, the values of the equivalent series resistance (ESR) and charge transfer resistance (Rct) are recorded for the fabricated supercapacitors.The introduced supercapacitors fabricated using graphene-PANI nanocomposites electrodes produce maximum specific capacitance with an increase of 5.17 times with respect to graphene supercapacitors and 2.54 times with respect to PANI supercapacitors. Supercapacitors fabricated using aqueous electrolyte show high specific capacitance with an increase of 1.32 times with respect to polymer electrolyte supercapacitors. Finally, temperature effect on specific capacitance is studied where specific capacitance is found to be stable in temperature range between 25-70 ˚C.