Elucidating the nature of grain boundary resistance in lithium lanthanum titanate

Solid electrolytes for all-solid-state batteries are generating remarkable research interest as a means to improve the safety, stability and performance of rechargeable batteries. Solid electrolytes are often polycrystalline and the effect that grain boundaries have on the material properties is often not fully characterised. Here, we present a comprehensive molecular dynamics study that quantifies the effect of grain boundaries on Li-ion transport in perovskite Li3xLa(2/3)-xTiO3 (0 < x < 0.16) (LLTO). Our results predict that grain boundaries hinder Li-ion conductivity by 1 to 2 orders of magnitude compared to the bulk. We attribute the poor Li-ion conductivity of the grain boundaries to significant structural alterations at the grain boundaries. Our detailed analysis provides important insight into the influence of grain boundary structure on transport of Li-ions in solid electrolyte materials.

Automated summary

This study quantifies the impact of grain boundaries on Li-ion transport in LLTO solid electrolyte materials through molecular dynamics simulations, revealing that grain boundaries significantly reduce the conductivity of Li-ions. These findings provide important insights into the influence of grain boundary structures on Li-ion transport in solid electrolytes.