Preparation and improvement electrochemical properties of transition metal Zn-doped NiS nanospheres

In this paper, the NiS- and Zn-doped NiS nanospheres were prepared by solvothermal method, respectively. The structural characterizations are studied by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectrometer (EDS). The results show that the NiS- and Zn-doped NiS nanospheres with high specific surface areas and perfect crystallization were obtained. The Ni atoms are replaced partly by Zn atoms in NiS by doping. Electrochemical performance was tested by cyclic voltammetry (CV), the galvanostatic charge-discharge analysis (GCD), and electrochemical impedance spectrometry (EIS). The experimental results show that the synthesized Zn-doped NiS nanospheres exhibit better rate capability and cyclic stability than that of pure NiS microspheres. The electrochemical performance of obtained Zn-doped NiS nanospheres with the high specific capacitance of 894.3 F g−1 at 1 A g−1 has been dominantly improved.