Synthesis Of A Novel Anode Material Of MeS For Li-ion Batteries And Its Electrochemical Property Study

As electrochemical power sources, Li-ion batteries (LIBs) have the advantges of high operation voltage, high energy density, safty and environmental benignity, and so on. They have the wide application potential in the fields of electronic vehicles, hybrid electronic vehicles and energy storage systems for wind and solar energies. However, commercial Li-ion batteries have limited electrochemical performance such as low power density and low capacity, which cannot meet the demands for the next generation LIBs. Therefore, a great many of alternative electrode materials have been studied. Among different candidates, metal sulfides are promising electrode materials due to theirtheir novel electrochemical properties and important technological applications.Many types of metal sulfides have been investigated as both cathode and anode materials for LIBs. As a light metal sulfide, MgS is abundance and low cost. Metal sulfides have aroused more and more attentions on the basis of their novel electrochemical properties and important technological applications. Therefore, exploting other metal sulfides of novel electrochemical property as electrode materials for LIBs applications with novel synthesis is still necessary.As a kind of light metal sulfides, MgS has the metrits of abundance and low cost, etc.. Based on an overall review on the research and development of metal sulfides, MgS was study firstly as an electrode material of LIBs. In this work, Mg, MgH2, S and acetylene black (C) were used as starting materials. Mg and MgH2were ball-milled with S, respectively, to synthesize MgS, and then the synthesized MgS was further milled with C to form MgS/C composite. Alternatively, S and C were pre-milled and then milled with MgH2, to form MgS/C composite, In addition, MgH2was milled with C, and then heated with S, to form MgS/C composite. The structure and electrochemical properties of the synthesized composites were investigated by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM) and high resolution TEM and galvanostatic charge-discharge and cyclic voltammetry measurement, etc. The results shown that both Mg and MgH2reacted with S forming MgS in the present methods. The MgS/C derived from ball milling mthod shows smaller size of the MgS/C particles than that of the one derived from thermal synthesis, being mainly less than1μm, and the MgS shows nanocrystallite feature, embedded in the C matrix, especially for the MgS/C derived from MgH2and S/C, showing much smaller MgS/C particle size and MgS nanocrystalliite size. It shows excellent electrochemical properties as anode material for LIBs. It shows a high initial discharge capacity of1741mAh/g with a coulomb efficiency of81%.The capacity fading occurs mainly in the first several cycles, thereafter, the capacity tends to be stable. A high capacity of630mAh/g is matained after80cycles. Moreover, the mechanism of the lithium reaction processes were primarily discussed by XRD and HRTEM.