Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr, 3, 14195, Berlin, Germany.
Sci Rep. 2017 Jul 19;7(1):5873. doi: 10.1038/s41598-017-05775-2.
We have studied temperature-induced superionic phase transition in LiS, which is one of the most promising Li-S battery cathode material. Concentration of ionic carriers at low and high temperature was evaluated from thermodynamics of defects (using density functional theory) and detailed balance condition (using ab initio molecular dynamics (AIMD)), respectively. Diffusion coefficients were also obtained using AIMD simulations. Calculated ionic conductivity shows that superionic phase transition occurs at T = 900 K, which is in agreement with reported experimental values. The superionic behavior of LiS is found to be due to thermodynamic reason (i.e. a large concentration of disordered defects).
我们研究了 LiS 中的温度诱导超离子相转变，LiS 是最有前途的 Li-S 电池阴极材料之一。分别从缺陷热力学（使用密度泛函理论）和详细平衡条件（使用从头算分子动力学（AIMD））评估低温和高温下的离子载流子浓度。还使用 AIMD 模拟获得了扩散系数。计算得到的离子电导率表明，在 T = 900 K 时发生超离子相转变，这与报道的实验值一致。LiS 的超离子行为归因于热力学原因（即大量无序缺陷的存在）。
