Nickel induced in situ growth of nickel hydroxide nanoflakes on reduced graphite oxide with high energy and power density.

Layered hexagonal Ni(OH)2 nanoflakes have been successfully fabricated on the surface of reduce graphite oxide (rGO) via nickel induced in situ growth in this study. The layers number and size of Ni(OH)2 nanoflakes could be controlled by adjusting the concentration of Ni2+ precursors with nickel as active site on rGO surface. In the three electrode systems, the composite showed a relatively high specific capacitance achieved 1012.2 F∙g-1 at current density of 1 A∙g-1 with coulombic efficiency of 98.3%. As assembled in asymmetric devices (Ni(OH)2 nanoflakes loaded on rGO as positive electrode and active carbon as negative electrode), the maximum specific capacitance reaches to 260.9 F∙g-1 at current density of 0.5 A∙g-1 and the energy density can be maintained at 71.1 Wh∙kg-1 at power density of 26.95 kW∙kg-1 with good rate capability and acceptable cycling stability.