A Universal Solid Reaction Enabling Nanosized Li₂S in an Amorphous Matrix for All-Solid-State Li-S Batteries

Lithium sulfide (Li₂S), a key cathode material for all-solid-state lithium-sulfur (Li-S) batteries, faces challenges such as low electronic and ionic conductivities and limited active material utilization during cycling. In this study, we developed a new cathode featuring nanosized Li₂S embedded in an amorphous LiFeS₂ matrix (92Li₂S@8LiFeS₂). Benefiting from the mixed electronic and ionic conductivities of LiFeS₂ along with its catalytic effect and the nanosized Li₂S that shortens electron and ion transport distances, this 92Li₂S@8LiFeS₂ cathode exhibits long-term cycling stability with a capacity retention of over 99% after 320 cycles. With an active material content of 48% and a mass loading of 19.1 mg/cm², the cathode achieves an areal capacity of 13.2 mAh/cm². This work presents a facile and novel approach to designing Li₂S-based cathodes for high-performance, all-solid-state Li-S batteries.