Preparation of novel three-dimensional NiO/ultrathin derived graphene hybrid for supercapacitor applications.

A new type of three-dimensional (3D) NiO/ultrathin derived graphene (UDG) hybrid on commercial Ni foam (NF) for a binder-free pseudocapacitor electrode is presented. NiO nanoflakes are in situ grown by a chemical bath deposition (CBD) technique on the free-standing 3D UDG/NF scaffold, which is first prepared by a simple nanocasting process consisting of hydrothermal reaction and subsequent thermal transformation. The 3D UDG/NF scaffold with interconnected network affords a high conductivity due to the high graphitization degree and efficiently facilitates the electron transport to NiO. Moreover, the 3D NiO/UDG/NF hybrid allows for a thinner 3D active material layer under the same loading density, which could shorten the diffusion paths of ions. The NiO/UDG/NF hybrid is directly used as a binder-free supercapacitor electrode, which exhibited significantly improved supercapacitor performance compared to the bare CBD prepared NiO/NF electrode.