Preparation of rGO/NiO nanocomposites by AC and nanosecond pulsed DBD

Graphene/transition metal oxide composites combine the energy-storing mechanisms of pseudo-capacitance and double layer capacitance, and are considered as preferred electrode materials for supercapacitors. For the composites' complex structure and components, it is important to develop a method with good controllability to monitor the structure and component of the nanocomposites, which is critical for the electrochemical performance optimization and the further industrial application. In this paper, graphene oxide (GO) and nickel acetate tetrahydrate (Ni(CH3COO)2·4H2O) were used to prepare reduced graphene oxide/nickel oxide (rGO/NiO) nanocomposites utilizing dielectric barrier discharge (DBD) plasmas with AC and nanosecond (ns) pulse power supplies. The scanning electron microscope (SEM), Raman spectra, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) are used to study the nanocomposites created under various discharge conditions. It shows the splitting and delamination of the prepared composites surface, a rise in ID/IG, and the reduction of GO after plasma treatment result in an excellent connection with the electrode material surface and electrolytic solution, and good capacitor performance. The rGO/NiO nanocomposites prepared by AC DBD have better charge transfer resistance, conductivity, and electrochemical capacitance retention rate than the materials prepared by ns pulsed DBD, which is analysed by power deposition and thermodynamics. The work contributes to reveal the mechanism of plasma material preparation, which will give new impetus to the development of environmental-friendly method for electrode materials preparation.