Fabrication of Ni<inf>3</inf>S<inf>2</inf>-functionalized V<inf>2</inf>O<inf>3</inf> nanospheres as promising anode materials for rechargeable batteries and supercapacitors

Abstract

Supercapacitors (SCs) and lithium-ion batteries (LIBs) are the current representatives for high power applications in the future. In this concern, a simple solvothermal technique was directly implemented to fabricate Ni3S2-decorated V2O3 nanospheres as a potential anode material for LIB and SC applications. X-ray diffraction analysis (XRD) showed the formation of rhombohedral V2O3 structure as major phase, while rhombohedral Ni3S2 and tetragonal VO2 are existed as minor phases. Fourier Transform Infrared Spectrometer (FTIR) inspection revealed the corresponding vibrational modes for V–O–V, V=O, Ni–S and C=S bonds, respectively. Transmission electron microscope (TEM) images of the as-synthesized composite sample exhibited unique strings of nanosized sphere-like morphology. Energy dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (SAED) techniques confirmed the existence of both oxide and sulphide components. Analysis of XPS V2p spectra demonstrated the presence of V4+ and V3+ species, showing a high agreement with the obtained results from X-ray Rietveld analysis. The prepared Ni3S2@V2O3 composite supercapacitor electrode delivered a high specific capacitance ~ 1535 F g−1 at 5 mV.s−1 and 295 F g−1 at 50 mV s−1. Meanwhile, the fabricated Ni3S2@V2O3 battery anode stored about 550 mAhg−1 at 0.1 A g−1. Electrochemical impedance spectroscopy (EIS) results for the assembled lithium batteries revealed a good polarizability and reversibility upon multiple galvanostatic cycling up to 100 cycles.