Mesoporous Zinc–Nickel–Cobalt nanocomposites anchored on graphene as electrodes for electrochemical capacitors

This study reports a facile, environmentally-friendly and scalable liquid-phase exfoliation of HOPG process combined with a simple solvothermal method, consequently with calcination for the synthesis of highly porous graphene/Zinc–Nickel–Cobalt (ZNC) nanosheets arrays. The crystallographic and morphological information of the nanostructures were evaluated by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) Transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscope (HR-TEM). Given its unique architecture and composition, the nanocomposites were analysed as electrode materials for electrochemical capacitor. Additionally, different graphene/(ZNC) nanocomposites composed of various mass loading of graphene to ZNC were prepared under the same synthesis conditions and the results revealed that the mass loading of the precursors significantly influenced the electrochemical behaviour of the active electrode materials. The electrochemical performance of the graphene-(ZNC) electrode prepared at a mass loading of 0.3 of graphene and labelled G3-(ZNC), exhibited fascinating specific capacitance of 502 Fg-1 at current density of 0.2 Ag-1 and with excellent cycling stability of 82% capacitance retention after 2600 cycles.