Effect of Strain on the Ionic Conductivity of Solid Electrolytes in All-Solid-State Batteries

立方- li7la3zr2o12 （c-LLZO）和Li10GeP2S12 （LGPS）是很有前途的锂离子电池固体电解质材料。然而，为了实际应用，这些电解质在室温下的离子电导率仍然需要改进。操纵晶格应变是控制固体电解质材料离子电导率的一种新策略。在本项目中，我们将利用基于dft的缺陷热力学和从头算分子动力学研究应变对c-LLZO和LGPS中Li输运机制和电导率的影响。在基本方面，我们的目标是研究一种计算效率高且准确的理论方法（称为“弹性偶极张量”方法），以预测任何给定外部应变下固体电解质中离子载流子的形成能（载流子浓度）、迁移势垒（载流子迁移率）和电导率。对于复杂材料，如固体c-LLZO和LGPS电解质，这种方法的有效性将被检验。这项工作的结果可能是理解应变对全固态电池速率能力影响的重要一步。

Cubic-Li7La3Zr2O12 (c-LLZO) and Li10GeP2S12 (LGPS) are promising solid electrolyte materials for Li-ion batteries (LIB). However, for real application the ionic conductivity of these electrolytes at room temperature still needs to be improved. Manipulation of lattice strain is a new strategy to control the ionic conductivity of solid electrolyte materials. In this project, we will study the influence of strain on the mechanism and conductivity of Li transport in c-LLZO and LGPS using DFT-based thermodynamics of defects and ab initio molecular dynamics. On the fundamental side, our goal is to investigate a computationally efficient and accurate theoretical approach (named “elastic dipole tensor” approach) to predict the formation energy (concentration of carriers), migration barrier (mobility of carriers), and conductivity of ion carriers in solid electrolytes for any given external strain. The validity of this approach for complex materials such as solid c-LLZO and LGPS electrolytes will be examined. The results of this work can be an important step toward understanding the effect of strain on the rate capability of all-solid-state batteries.