Ultrathin and Highly Crystalline Co3O4 Nanosheets In Situ Grown on Graphene toward Enhanced Supercapacitor Performance

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.