Insight into the effect of strain on Li-ion diffusivity and conductivity in Li3OCl anti-perovskite solid-state electrolyte: A perspective from AIMD simulations

Abstract

Utilizing first-principle calculations, this study elucidated the underlying mechanism of elastic strains affecting the Li-ion diffusivity and conductivity in Li3OCl anti-perovskite solid-state electrolyte. Strain was shown to modulate the Li-ion vibrational amplitude, attempt frequency and adjacent site jumps, as revealed by ab initio molecular dynamics (AIMD) simulation post-processing. Additionally, analysis of lattice dynamics and phonon behavior under various strain conditions demonstrated that tensile strains soften the lattice and lower the phonon band center frequency, thereby diminishing the energy barriers impeding ion transport. Further, we have systematically investigated strain-induced distortions of the coordination environment via continuous symmetry measures (CSM), assessing the variations at initial and saddle sites along the Li-ion migration routes. And the study of bonding variability under strain provided a deeper understanding of strain-induced conducting behavior. These results underscore insights into the fundamental mechanisms governing ionic transport in Li3OCl anti-perovskite under elastic strain, highlighting the potential of strain engineering as a promising avenue for optimizing the performance of solid-state electrolytes in energy storage applications.