▎ 摘　　要

Ruthenium oxide/graphene (RuO2/G) nanocomposites for supercapacitor applications were prepared by a hydrothermal method using high-quality graphene, which was synthesized by modified hummer's method from the graphite. The results reveal that the RuO2 nanoparticles are evenly dispersed on the graphene sheets. The contact between the RuO2 nanoparticles and graphene can effectively improve the conductivity of RuO2 and prevent the restacking and agglomeration of graphene. In addition, the composites exhibit a good electrochemical-activation behavior, and the graphene in composites significantly influences the electrochemical performance. The RuO2/G composite displays a specific capacitance of 441.1 F g(-1) at 0.1 A g(-1), and only 6% of the capacitance degrades after 1000 cycles, which demonstrates the composite's excellent cycle stability. Significantly, the RuO2/G composites can achieve a high voltage window of 1.6 V and increase energy density of 61.2 Wh kg(-1) at a power density of 183.8 W kg(-1) at 1 M of Na2SO4 electrolyte. This attractive performance makes it a promising candidate as an electrode material for supercapacitors.