Flexible Ni-Foam-Based Electrode with Novel MoS2/NiO Nanocomposite for Superior Supercapacitor Applications

Abstract

In the present work, a simple and effective hydrothermal method has been used to synthesize a nanocomposite of nickel oxide and molybdenum disulphide. Structural and optical characterizations of the as-synthesised MoS2/NiO nanocomposite nanoparticles were carried out using X-ray diffraction (XRD) and UV-visible spectroscopy techniques. The major peaks of MoS2 and NiO were detected in XRD, confirming the formation of a composite. The reduced band gap of 2.84 eV of MoS2/NiO nanocomposite, as compared to pure NiO with a 3.1 eV bandgap, indicates a blue shift. The surface morphology of MoS2/NiO nanocomposite was measured using field-emission scanning electron microscopy, showing a sheet-like structure with fine particles overlaid on them. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to determine the processes of charge transfer between electrodes, diffusion of molecules and ions within the electrolyte solution, and ion adsorption on the surface of the the electrode. The as-prepared composite shows an enhanced specific capacitance of 246 F g−1 at20 mV sec−1, a scan rate of which was more than both base materials in pristine form. EIS results thus obtained may give a new direction for supercapacitor applications with the as-synthesized sample.