Diffusion in Li2O studied by non-equilibrium molecular dynamics for 873 < T/K < 1603

Abstract

The use of non-equilibrium molecular dynamics facilitates the calculation of the cation diffusion constant of Li₂O at temperatures too low to be accessible by other methods. Excellent agreement with experimental diffusion coefficients has been obtained over the temperature range 873 < T/K < 1603. Diffusion below 1200 K was shown to be dominated by a concerted nearest-neighbour hopping process, whereas in the high-temperature superionic region an additional mechanism involving a six-coordinate interstitial cation site in the anti-fluorite structure becomes increasingly dominant. Our model thus accounts for the transition from the superionic regime to the non-superionic regime.