An interlayer for a lithium-sulfur (Li—S) battery may include a separator coated with an intercalation compound. The intercalation compound may intrinsically exhibit and/or be modified to have a higher affinity for lithium polysulfides (LiPS), thus reducing the global sulfur mobility and the shuttling effect. Additionally, the intercalation compound may also reduce the formation of a Li2S clogging layer, which thus increases the battery lifetime by reducing active material loss and maintaining the rate performance of the Li—S battery. Unlike conventional inactive interlayer materials, the intercalation compound may also contribute to the capacity of the battery, thereby increasing the volumetric and gravimetric energy densities. In one example, an interlayer for the Li—S battery may be disposed between a cathode and an anode and may include a separator and a coating disposed on the separator. The coating may include an intercalation compound, such as Chevrel-phase Mo6S8, to reduce the global sulfur mobility.