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

We report that 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.