Diffusivities and lithium distributions in Li₆PS₅X (X = Cl, Br, I) and Li₇PX₆ (X = S, Se) are investigated by means of molecular dynamics simulations. The best lithium conduction is found in Li₆PS₅Cl with diffusivity of over 1 S/cm at 600 K. The halide rich Li₅PS₄Cl₂ shows promising results with diffusivity of over 2 S/cm at 600 K, performing better in simulations than the existing compounds.

Simulations show a beneficent effect of chlorine and bromine disorder on anion sites, opening lithium pathways in the neighborhood and enabling higher conductivities. No significant influence of vacancies on the diffusivity of lithium in these materials can be reported. Lithium jump rates in both material families are in the order of 10¹⁰ s^-1, while Li₆PS₅Cl and Li₅PS₄Cl₂ show the highest jump rates of respectively 2.10·10¹¹ s^-1 and 2.14·10¹¹ s^-1 at 600 K.