Realization and characterization of flexible supercapacitors based on doped graphene electrodes

High energy consumption leads to the development of various energy types. As a result, the storage of these different types of energy becomes a key issue. Supercapacitors, as one important energy storage device, have gained much attention especially on electrode materials. The aim of this work is the realization of a flexible supercapacitor using graphene-doped metal oxides graphene/polypyrrole (GP/PPY) nanocomposites as electrodes. Exfoliation and in situ polymerisation are used for graphene and polypyrrole preparation. Metal oxide nanoparticles (Fe2O3 and NiO) are synthesised via green synthesis technique that based on olive leaves' extract. Gel polymer (polyvinyl alcohol (PVA)-potassium hydroxide (KOH)-hydroquinone (HQ)) is used as an electrolyte and separator. The structural and morphological properties of these components are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscopy (SEM). Electrochemical tests are used to study the effect of the nanooxide particles and the different components of the electrolyte and the separator on the supercapacitor behavior. These tests show a stable supercapacitor for more than 50,000 cycles and different values of the specific capacity are obtained as a function of the combination between metal oxide nanoparticles (Fe2O3 and NiO) and separators (PVA, KOH, HQ and GP/PPY).