Nickel-copper graphene foam prepared by atmospheric pressure chemical vapour deposition for supercapacitor applications

摘要

This study reports on Ni and Ni-Cu graphene foam prepared by atmospheric pressure chemical vapour deposition. The Ni-Cu foam alloys were prepared using a three-dimensional (3D) scaffold template of polycrystalline nickel foam which is commonly used as a current collector in supercapacitor electrodes. The morphological, composition and structural characterization of as-grown Ni and Ni-Cu graphene foam were carried out using confocal Raman spectroscopy imaging, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that Ni -Cu graphene foam is mainly monolayer and bilayer as compared to Ni graphene foam which is typically a few-layer graphene. The electrochemical performance of Ni and Ni-Cu graphene foam as current collectors were evaluated in a three-electrode electrochemical cell using 1 M NaSO4 aqueous electrolyte and porous activated carbon (AC) produced from lightweight material cork (Quercus suber) as the active electrode material. The AC on Ni-Cu graphene foam current collectors exhibited a high specific capacitance (250-300 F g(-1) at 1 A g(-1)) and good electrochemical stability (94-100% capacitance retention) over 6000 constant charge-discharge cycles at 5 A g(-1).