A solid-state reaction route to anchoring Ni(OH) 2 nanoparticles on reduced graphene oxide sheets for supercapacitors

Abstract

A mechanically assisted solid-state reaction method is employed to prepare graphene/Ni(OH) 2 nanocomposites for supercapacitor electrode materials. Morphological analyses reveal that, at a loading 50 wt % Ni(OH) 2, nanoparticles with an average size of ∼10 nm are formed and uniformly dispersed on the surface of reduced graphene oxide sheets functionalized with benzenesulfonate. Electrochemical measurements of the composite material show a high specific capacitance of 1568 F g -1 (based on nickel hydroxide) at a current density of 4 A g -1, significantly higher than that of bare Ni(OH) 2 nanoparticles prepared without the use of graphene. This much improved electrochemical performance is enabled by both the well-dispersed Ni(OH) 2 nanoparticles that offer large accessible surface area and the hydrophilic functional groups on graphene surface that facilitate electrolyte transport. The scalable solid-state synthesis developed in this work is promising for a green chemical approach to the preparation of supercapacitor electrode materials with high performance. © 2012 American Chemical Society.