All‐Solid‐State Li–S Batteries Enhanced by Interface Stabilization and Reaction Kinetics Promotion through 2D Transition Metal Sulfides

All‐solid‐state lithium‐sulfur batteries (ASSLSBs) based on sulfide solid‐state electrolytes (SSEs) provide prospectively high energy density and safety. However, the low conductivity and sluggish reaction kinetic of sulfur cathode limit its commercialization. The use of carbon additives can improve the electrical conductivity but accelerates the decomposition of SSEs. Herein, a highly conductive carbon fiber decorated with hybrid 1T/2H MoS2 nanosheets is designed. The high chemical and electrochemical compatibility among MoS2 and sulfide SSE can greatly improve the stability of the cathode and therefore maintain pristine interfaces. The uniform distribution of electrical‐conductive metallic 1T MoS2 on carbon fiber benefits the electron transfer between carbon and sulfur. Meanwhile, the layered structure of MoS2 can be intercalated by a large amount of Li ions facilitating ionic and electronic conductivity. In consequence, the charge transfer and reaction kinetics are greatly enhanced, and the decomposition of SSEs is successfully relieved. As a result, the ASSLSB delivers an ultrahigh initial discharge and charge capacity of 1456 and 1470 mAh g−1 at 0.05 C individually with ultrahigh coulombic efficiency and maintains high capacity retention of 78% after 220 cycles. The batteries also obtain a remarkable rate performance of 1069 mAh g−1 at 1 C.