Impact of LiCl Schottky Defects on Structure and Ion Transport in Melt-Quenched Li-Rich Antiperovskites: A Molecular Dynamics Investigation

Recently discovered Li3OCl antiperovskites have emerged as promising solid electrolytes; however, literature reports significant variability in their ionic conductivity. To resolve this inconsistency, we emulated the experimental melt-quenching process of Li3−δOCl1−δ antiperovskites over controlled LiCl Schottky defect concentrations, δ = 0 to 0.2, using classical molecular dynamics simulations. The resulting quenched phases form composite structures comprising crystalline and amorphous regions. Interestingly, the quenched phases not incorporating Schottky defects (δ = 0) measured an appreciable Li+ conductivity of 0.39 mS/cm at 450 K, while the highest ionic conductivity of 1.64 mS/cm is observed for the intermediate composition of δ = 0.05. Detailed structural and dynamical investigations unveil a direct correlation between the degree of amorphocity and Li+ mobility in these matrices. We present evidence suggesting that amorphous regions within the melt-quenched matrices act as percolation pathways for long-range Li+ transport.