Nanostructured nickel sulfide synthesized via a polyol route as a cathode material for the rechargeable lithium battery

Nanostructured nickel sulfide (NiS) was synthesized via a simple polyol route. The NiS powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and electrochemical testing. The results revealed that the cycle life of the annealed NiS sample was improved over that of the as-prepared sample. The electrochemical performance was also tested using 1 M lithium trifluoromethanesulfonimide (LiTFSI) in a solvent of poly(ethylene glycol) dimethyl ether (PEGDME) in order to compare with a sample tested in the conventional electrolyte of 1 M LiPF6 in a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). The results showed that the electrochemical properties were improved by using the 1 M LiTFSI/PEGDME electrolyte.