Computational Analysis of a Promising Earth Abundant, Stable, Lithium Solid Electrolyte

Solid state electrolytes offer the potential to drastically increase the overall stability of rechargeable lithium batteries as well as provide the means to realise the use of Li-metal anodes maximising the charge capacity of a device. At present, batteries use liquid electrolytes such as [LiPF₆]^- which although they possess high ionic conductivities of 1x10^-2S cm^-1limit the safe temperature ranges a battery can be operated at as well as forbidding the use of Li-metal anodes due to dendrite formation leading to short circuiting and “thermal runaway”. Solid electrolytes such as the Li-rich garnet materials, LLZO, or anti-perovskites, Li₃OCl, have demonstrated low migration barriers (<0.3 eV), however issues arise regarding stability or a competing lower conductivity phase. In this work, we have identified a promising Earth-abundant, non-toxic, stable Li-solid electrolyte. Using a combination of density functional theory and experiment, we show that this material possesses thermodynamic, dynamic and electrochemical stability, ideal defect chemistry and low migration barriers leading to undoped conductivities of ~10^-5S cm^-1 which are expected to rise to at least 10^-3 S cm^-1 with minimal doping.