In-situ controllable growth of α-Ni(OH)2 with different morphologies on reduced graphene oxide sheets and capacitive performance for supercapacitors

Abstract

The α-Ni(OH)2 nanowires (α-Ni(OH)2 NWs) and nanoparticles (α-Ni(OH)2 NPs) were grown on reduced graphene oxide (RGO) sheets by adjusting the reduction degree of the substrates. The α-Ni(OH)2 NWs/RGO composite was achieved by using graphene oxide (GO) as the substrate. In contrast, the α-Ni(OH)2 NPs/RGO composite was obtained when RGO was applied as the support. The difference in morphology can be attributed to the fact that the hydrophilic function of GO is larger than that of RGO, and sp2 carbon atom concentration in α-Ni(OH)2 NPs/RGO is higher than that in α-Ni(OH)2 NWs/RGO. When α-Ni(OH)2 NWs/RGO and α-Ni(OH)2 NPs/RGO composites were used as electrode materials for supercapacitors, the α-Ni(OH)2 NPs/RGO exhibits superior electrochemical performance than α-Ni(OH)2 NWs/RGO, which is attributed to the fact that the specific surface area, conductivity, and sp2 carbon atom concentration of α-Ni(OH)2 NPs/RGO are larger than those of α-Ni(OH)2 NWs/RGO. The α-Ni(OH)2 NPs/RGO composite is a promising candidate as electrode material for high performance supercapacitor.