Tailoring the Interface between Sulfur and Sulfide Solid Electrolyte for High-Areal-Capacity All-Solid-State Lithium-Sulfur Batteries

Fabricating high-capacity all-solid-state lithium-sulfur batteries (ASSLSBs) with long lifetimes is realistically challenging because of the poor ionic contact between the insulating element sulfur (S-8) and the solid electrolyte at the solid-solid interface. Herein, an inorganic Li-ion-conducting species composed of polysulfido-inter-mediate compounds (3Li(+)-PS4+n3- (n = 0)) is incorporated between S-8 and the sulfide solid electrolyte (SSE) of Li6PS5Cl (LPSCl) to enhance the ionic contact of S-8. A weakly polar solvent which is included in the mixing process but eventually removed promotes interfacial chemical reactions between S-8 and LPSCl, significantly enhancing the wettability of LPSCl toward the active material (S-8). This maximizes the utilization of S-8, facilitates interfacial Li-ion transport, and enhances the mechanical properties of the solid-state S cathode. As a result, a high-performance ASSLSB with a high areal capacity (5.1 mAh cm(-2)) and promising lifetime (250 cycles) at room temperature, operating at a current density of 1 mA cm(-2), is successfully developed.