Facile preparation of reduced graphene oxide - ruthenium oxide nanocomposite electrodes for high-performance supercapacitors

Herein we report a facile approach of synthesis of graphene oxide (GO) sheets modified with ruthenium oxide (RuO$_{2}$) nanoparticles, followed by a reduction of graphene oxide in an alkaline medium. The as-prepared reduced graphene oxide (rGO)/ruthenium oxide (RuO$_{2}$) nanocomposite was used for the fabrication of a symmetric supercapacitor. The specific capacitance and charge-discharge periods of the supercapacitor were found to be dependent on both the structural and morphological properties, and the electrolytes used. Surface morphology analysis using scanning electron microscopy (SEM) shows the RuO$_{2}$ nanoparticles decorating rGO sheets, comprising a highly porous surface. Structural analysis obtained by x-ray diffraction (XRD) revealed an amorphous structure that is necessary to achieve a high cycling rate capability. The electrochemical properties of rGO/RuO$_{2}$ were measured in a two electrodes system, using two different electrolytes: H$_{2}$SO$_{4}$ and Na$_{2}$SO$_{4}$. The specific capacitance of rGO/RuO$_{2}$ in H$_{2}$SO$_{4}$ was found to be 318 F/g, and is much higher than that of Na$_{2}$SO$_{4}$ (184 F/g).