中文摘要：

采用第一性原理的平面波赝势法计算Li-Ga-S体系LiGa,Li2S,GaS,Ga2S3和LiGaS2的热力学数据,分析可能发生的化学反应,其中4个化学反应可以生成目标产物LiGaS2.单质直接化合生成LiGaS2的反应自由能变较高,Li2S与Ga2S3化合生成LiGaS2的反应自由能变随温度升高而降低,但体系很难获得Ga2S3,LiGa与S生成LiGaS2和Li2S与GaS化合生成LiGaS2的自由能变较小,且体系生成Li2S,GaS和LiGa的自由能变也较小,由此推断LiGaS2多晶原料可以通过后两个反应获得.

英文摘要：

First-principles study of LiGa Li2S, GaS, Ga2S3 and LiGaS2 thermodynamic functions in Li-Ga-S system was performed by using plane-wave pseudopotential method. All possible chemical reactions were analyzed. It was found that the goal product LiGaS2 comes from four chemical reactions. Free energy change of direct synthesis from elements is high. Free energy change of synthesis from Li2 S and Ga2S3 decreases with increasing temperature, but Ga2S3 is difficult to be obtained. These two reactions can not occur in this system. The remaining reactions by LiGa and S method and Li2S and GaS method can occur due to their low free energy changes. Free energy changes generating LiS, GaS and LiGa are low.