中文摘要：

结合实验和第一性原理计算,对MoS_2首次充放电过程中的第一阶段相变的结构变化进行了研究。研究表明1.1V处的电压平台对应于锂离子嵌入量0.56,锂离子都是嵌入2H相的八面体空位,与计算出的平台电压值及MoS_2的相稳定特性都相吻合.但当锂离子嵌入量超过1.0时,晶体结构向无定形结构转变,导致后续充电过程中不出现平台特征.此外,通过对比MoS_2和LiCoO_2的嵌入能量项,本文探究了决定正极与负极材料本征电压差的物理机制。

英文摘要：

By combining experimental methods with first-principles calculations this article reports the determination of the structural characters of MoS2 in the first discharging and charging cycling,where the first stage phase transformation occurs.The significant voltage plateau at 1.1 V is attributed to lithium insertion on octahedral vacancy sites of2H-Li_xMoS_2 with lithium concentration（x） up to 0.56,which corresponds with the calculated voltage and phase stability of MoS_2.However,the ensuing amorphization for x over 1.0 immediately removes the plateau character from the charging curve.Furthermore,we offer a comparison to LiCoO_2 to investigate the physical mechanism of the anode and cathode voltaic.