Exploring Defects and Dopability Limits of Solid Electrolytes: a Computational Study

Negligible electronic conductivity is a crucial requirement that solid electrolytes must meet before they can be considered in all-solid-state lithium batteries. Electronic conductivity is strongly driven by charged defects. Understanding the defect chemistry of solid electrolytes is therefore essential to assess their performance and suitability. In this work, we use first-principles computations to investigate the intrinsic defect chemistry of six solid electrolytes in order to determine their robustness to developing electronic conductivity. We conclude that some electrolytes can be prone to problematic levels of electronic conductivity (e.g., LiTi2(PO4)3) while others such as Li3PS4 have intrinsically low electronic conductivities. We also show that most solid electrolytes are more likely to develop electronic conductivity in S/O-rich|Li-poor environments, translating to more sulfur-rich or oxidative atmospheres and higher electrochemical potentials (> 4 V vs. Li+/Li).