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

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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.