Fig. 1.

Schematic illustration of the sulfur conversion process and the Li₂S catalytic oxidation on the surface of the substrate. (A) Sulfur adsorbs on the surface of carbon and polar host and transforms to Li₂S_x, which is strongly bonded with the polar host while weakly adsorbed by nonpolar carbon (step 1). Li₂S_x transforms to Li₂S and is mainly captured by the polar host while isolated islands are deposited on the carbon surface (step 2). (B) The substrate catalyzes Li₂S decomposition and favors the oxidization of Li₂S to Li₂S_x near the substrate surface, and finally to sulfur (steps 3 and 4 in A).