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

Lithium-rich oxychloride antiperovskites are promising solid electrolytes for enabling next-generation batteries. Here, we report a comprehensive study varying Li+ concentrations in Li3OCl using ab initio molecular dynamics simulations. The simulations accurately capture the complex interactions between Li+ vacancies (V-Li '), the dominant mobile species in Li3OCl. The V-Li ' 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% V-Li '. 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 Li3OCl. This article is part of the Theo Murphy meeting issue 'Understanding fast-ion conduction in solid electrolytes'.