Impacts of vacancy-induced polarization and distortion on diffusion in solid electrolyte Li3OCl.

Abstract

Lithium-rich oxychloride antiperovskites are promising solid electrolytes for enabling next-generation batteries. Here, we report a comprehensive study varying Li+ concentrations in [Formula: see text] using ab initio molecular dynamics simulations. The simulations accurately capture the complex interactions between Li+ vacancies ([Formula: see text]), the dominant mobile species in [Formula: see text]. The [Formula: see text] polarize and distort the host lattice, inducing additional non-vacancy-mediated diffusion mechanisms and correlated diffusion events that reduce the activation energy barrier at concentrations as low as 1.5% [Formula: see text]. Our analyses of discretized diffusion events in both space and time illustrate the critical interplay between correlated dynamics, polarization and local distortion in promoting ionic conductivity in [Formula: see text]. This article is part of the Theo Murphy meeting issue 'Understanding fast-ion conduction in solid electrolytes'.