Hydrothermal synthesis and characterization of three-dimensional Ni-NiO on nickel foam substrate

Abstract Ni-NiO has been considered one of the most efficient and high energy materials for electrochemical devices due to their high energy density. In addition, unique surface morphology and higher surface area has made them promising candidates for supercapacitor and high-performance lithium-ion batteries. This research followed the hydrothermal synthesis route to fabricate three-dimensional Ni-NiO composites with nickel nitrate as a precursor and analyzed variation of surface morphology as a function of temperaturre. Advanced characterization techniques such as Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to analyze the Ni-NiO composites. All of the samples had uniform formation of nickel oxide on the nickel foam, according to SEM examination, with different morphologies dependent on the annealing temperature, including continuous films, ridge-like structures, and spherical nodules. The formation of NiO over nickel foam substrate was verified by EDX, which indicated that the nickel concentration ranged from 82.24% to 84.81% and the oxygen content from 15.19% to 17.76%. The content of oxygen tends to increase slightly as the annealing temperature rises. Furthermore, addition of urea with nickel nitrate increases the porosity of the NiO composite significantly.