The crystalline and glassy PS 4 3units in the initial structure are depicted using the same color scheme as in Fig. . Visual inspection reveals that the distribution of crystalline and glassy PS 4 3units at the initial state and after 10 ns remained unchanged, indicating no crystal growth at 300 K. Experimentally, crystallization of the β-Li 3 PS 4 phase in 75Li 2 S-25P 2 S 5 glass has only been confirmed above 490 K; the simulation results are therefore consistent with the real crystallization process.