β-Ni(OH)2 nanosheets grown on graphene as advanced electrochemical pseudocapacitor materials with improved rate capability and cycle performance

Nanosheets composite consisting of β-Ni(OH)2 and reduction graphene oxide (β-Ni(OH)2/RGO) was successfully synthesized by improved hydrothermal process as electrochemical capacitor materials. The β-Ni(OH)2/RGO composite was tested as positive electrode material in a KOH aqueous electrolyte. The results show that the sample exhibits a high specific capacitance of 1740.56 F/g at a charge and discharge current density of 2.5 A/g, and the specific capacitance of β-Ni(OH)2/RGO is as high as 1326 F/g, even if the current density increase to 50 A/g. What is more, it exhibits an excellent long cycle life along with 93.8% specific capacitance retained after 1000 charge/discharge cycles. This composite displays a great promise as electrode materials for supercapacitor.