Li6PS5Cl

Li6PS5Cl, often abbreviated LPSC, is a lithium argyrodite-type solid electrolyte used in all-solid-state lithium batteries. It combines a sulfide-based framework with a chloride component to create a fast-conducting medium for Li+ ions.

The material crystallizes in a cubic argyrodite structure (space group F-43m). Its anionic sublattice comprises PS4^3- tetrahedra and Cl- ions arranged in a close-packed framework, while Li+ ions occupy multiple interstitial sites within this framework. The resulting diffusion network supports rapid Li+ migration, contributing to relatively high room-temperature ionic conductivity for sulfide-based electrolytes.

Li6PS5Cl can be prepared by solid-state reaction or mechanochemical methods from precursors such as Li2S, P2S5, and LiCl. Typical syntheses involve mixing the precursors under inert conditions and heating at several hundred degrees Celsius, sometimes followed by ball milling and annealing to achieve a homogeneous phase.

In terms of properties, Li6PS5Cl exhibits a room-temperature ionic conductivity on the order of a few millisiemens per centimeter and a high Li+ transference number. It is generally stable against Li metal and compatible with many sulfide-derived electrodes, though it remains sensitive to moisture and air, requiring handling in inert or dry environments. The electrolyte offers a comparatively wide electrochemical stability window for sulfide-based systems, making it suitable for pairing with several common cathodes, though interfacial engineering is often needed to optimize performance with high-voltage materials.

Li6PS5Cl is a leading candidate among solid electrolytes for solid-state lithium batteries, valued for its combination of relatively high ionic conductivity, simple synthesis, and compatibility with lithium metal anodes.