Chips assembled cuboid-like nickel hydroxide/rGO composite material for high performance supercapacitors

In this paper, nickel hydroxide/rGO (Ni(OH)2/rGO) composite was successfully obtained in the existence of graphene oxide solution via hydrothermal method, with nickel nitrate hexahydrate as the nickel source, urea as the alkali source, and l-cysteine as the template. The structure and morphology of the composite were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), micro confocal laser raman spectroscopy (Raman) and BET surface analyzer. Finally, the electrochemical performance of the product was measured by electrochemical workstation. Morphological and structural analyses indicated that Ni(OH)2/rGO composite had good crystalline and a chips assembled cuboid structure with high specific surface area. Raman results indicated that the obtained composite has obvious D- and G-bands, which confirmed the Ni(OH)2/rGO composite was prepared successfully. Moreover, graphene was partially reduced during the hydrothermal reaction. Serving as the electrode material for supercapacitors, the Ni(OH)2/rGO composite exhibits high specific capacitance (1224 F/g at 2 A/g in the 3 M KOH), a nearly constant rate performance of 62.1% at current density ranging from 2 to 10 A/g, and 72.1% retention capacitance after 1000 continuous cycles. That indicates Ni(OH)2/rGO composite is promising electrode material for the electrochemical energy storage applications.