Nickel oxides/hydroxides-graphene as hybrid supercapattery nanocomposites for advanced charge storage materials – a review

This work presents a review of nanocomposites of nickel oxides (NiO, nickel cobaltite NiCo2O4), nickel hydroxides (Ni(OH)2), layered-double hydroxides of Ni (LDH-Ni) with graphene, functionalized-graphene (graphene oxide and reduced graphene oxide), doped-graphene (nitrogen doped and boron doped graphene) as hybrid supercapattery materials. The synergy between battery materials such as nanostructured nickel oxides, hydroxides, LDH-Ni with supercapacitors such as graphene/functionalized graphene/doped graphene, provides better energy storage performances than the pure materials. Although used battery cathodes, the nickel oxides/hydroxides were incorporated with graphene materials to enhance the charge density and the power density of the hydrid supercapattery nanocomposites. The higher power density and energy density of the hydrid supercapattery nanocomposites bridges the gap between batteries and supercapacitors. The reasons for the higher performance of the hybrid supecapattery electrodes compared to the pure nickel oxides/hydroxides are discussed. The review also presents the different types of synthetic process of the nanocomposites and future perspectives.