Controlled synthesis of Ni(OH)2/graphene composites and their transformation to NiO/graphene for energy storage

It has shown better electrochemical performance to use two dimensions (2D) nanomaterial nickel hydroxide nanosheets as electrode materials in energy storage research. However, when compared with carbon electrode material, the disadvantage of metal hydroxide is more obvious. In this study, we use Ni(OH)2/rGO composites (NGCs) synthesized by hydrothermal method as electrode materials to conduct an electrochemical property tests in 6 M KOH electrolyte solution. As a result, when current density of NGC8 samples (the mass ratio of Ni(OH)2 and graphene is 8:1) is 0.8 A g−1, the largest specific capacitance of composites is 1862.2 F g−1. What's more, when the current density is 15 A g−1, the capacitance only reduced to 91.6% after the constant current charge and discharge for 2000 cycles, which showed magnificent cycling stability. Further investigations, the 2D nanomaterial NGCs can be easily transmitted to NrCs (NiO/rGO composites), and delivers a specific capacitance of 782.5 F g−1 at a current density of 0.5 A g−1. These works are of great significance for the research of energy storage materials and the development of energy storage device.