▎ 摘　　要

Effective design of an electrode material is essential for energy storage and conversion of supercapacitor. Herein, a well-designed architecture of ultrathin and highly crystalline Co3O4 nanosheets (NSs) with a thickness of 2-3 nm are grown in situ on reduced graphene oxide (RGO) via a hydrothermal route and a subsequent calcination process. During synthesis, graphene oxide (GO) affects the growth of precursor. The Co3O4/RGO composites are employed as electrode material of supercapacitor with the aim of achieving the high electrochemical performance. The results indicate that Co3O4/RGO-2 electrode (the mass ratio of CoCl2 to GO is 10: 1) has the best performance with a specific capacitance of 3344.1 F g(-1) at a current density of 1.25 A g(-1), fine rate capability, and retention capacity of 87.9% even after 6000 cycles at 10 A g(-1). Such excellent performance is ascribed to the synergistic effects of ultrathin and highly crystalline Co3O4 NSs and its interacting model with RGO. This ultrathin sheet-sheet architecture will provide a promising for electrochemical fields.