for example, the formation energy of LiCl is the energy change associated with the reac-tion Li(s) + Cl 2 (g) -→ LiCl(s). We note that the formation of quinary compounds based on Li-P-S-In-Cl, and with varying stoichiometries, were also considered. While we found no enthalpic gain in forming these quinary compounds upon mixing Li 3 InCl 6 and Li 3 PS 4 at room temperature (i.e., under typical battery operation conditions), such decomposition products may form at very high temperatures, due to entropic stabilization.