▎ 摘　　要

A conventional one-pot hydrothermal approach for the synthesis of CeO2 nanoparticles on the surface of high-quality graphene, which was prepared using graphite flakes by modified Hummers method. The structural, morphological and elemental composition of the electrode samples is characterized by XRD, TEM, Raman, BET and XPS analysis. The XRD results exhibit the CeO2/Graphene nanocomposites were highly uniform in size and had a mean diameter of 30 nm. Electron microscopy displays CeO2 strongly anchor on graphene. An asym-metrical and symmetrical supercapacitor was designed by using the prepared electrodes. Due to the synergistic effect contributed by graphene and CeO2, CeO2/Graphene demonstrated excellent electrochemical efficiency, with a specific capacitance value of 782 Fg(-1) at 2 Ag-1. After 6000 cycles, high rate capability and 80.5% capacity retention were observed (long cycle life). Moreover, the fabricated asymmetric device (ASC) showed a maximum energy density of 43.5 Whkg(-1) and power density of 2180 Wkg(-1), respectively. The values are comparatively higher than other CeO2 based supercapacitor electrodes.