LAUSR

Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li6PS5X (X = Cl, Br, and I), a site-disorder between the anions S2– and X– has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such a disorder in Li6PS5Br can be engineered via the synthesis method. By comparing fast cooling (i.e., quenching) to more slowly cooled samples, we find that the anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with ab initio molecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within 1 min of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that lo...