A high performance supercapacitor based on a ceria/graphene nanocomposite synthesized by a facile sonochemical method

In this work, we have developed a novel nanocomposite material of ceria (CeO₂)-reduced graphene oxide (RGO) by a sonochemical route for application as a symmetric supercapacitor. CeO₂ nanoparticles have been anchored on RGO sheets in order to maximize the specific capacitances of these materials. Nanostructure studies and electrochemical performances of the CeO₂ nanoparticles on the RGO sheets were systematically investigated. The morphology and crystalline structure of the nanocomposites were examined by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). The electrochemical properties of the nanocomposite electrodes were examined by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements. The CeO₂-RGO nanocomposite electrodes exhibited excellent supercapacitive behavior with a high specific capacitance of (211 F g^-1 at 2 mV s^-1 and 185 F g^-1 at 2.0 A g^-1), high rate capability and good reversibility. The cycling stability of the electrode was measured by a continuous cyclic voltammetry (CCV) technique. Upon 4000 cycles, the specific capacitance of the electrode increases and reaches a maximum value of 105.6% of the initial value.