Fabrication and characterization of reduced graphene oxide modified nickel hydroxide electrode for energy storage applications

摘要

Electro-chemically synthesized nickel hydroxide Ni(OH)_2 on reduced graphene oxide (RGO) made from graphene oxide (GO) has been investigated as electrode materials for electrical energy storage applications. The electrochemical deposition of Ni(OH)_2 on highly hybridized RGO was more effective to improve the catalytic activity of electrode and to increase the capacity performance of the overall system. By virtue of the unique two-dimensional nanostructure of RGO, the as-obtained Ni(OH)_2 was closely protected by RGO, effectively suppressing their microstructural degradation during the charge and discharge processes, and enabling an enhancement in cycling capability. Electrochemical measurements demonstrated that the specific capacitance of the as-obtained supercapacitor is high as 729 mF/cm~2 and power density of 1.5 mW/cm~2. The electrical conductivity of RGO was determined to be 104 S/cm. In addition, there was no marked decrease in capacitance at a constant current density after 200 cycles, suggesting excellent long-term cycling stability.