Cathode Engineering Enables Robust Interface Contact for High-Performance All-Sulfide-Based Li-SeS 2 Solid-State Batteries

All-solid-state Li-sulfur batteries are promising candidates for next-generation energy storage systems, owing to their high energy density and capability to address the safety concerns and electrochemical stability challenges (e.g., the shuttle effect) inherent to liquid-based batteries. However, the electronic insulating nature and limited reactivity of sulfur result in sluggish kinetics, low utilization, and restricted cathode mass loading. Herein, SeS 2 is proposed as a cathode active material due to its enhanced electronic conductivity compared to sulfur. SeS 2 composite cathodes prepared with varying composite strategies exhibited significant differences in the electrochemical performance. Benefiting from enhanced interaction at the three-phase interface, the ball-milled SeS 2 /Li 6 PS 5 Cl/Ketjen Black composite cathode (SeS 2 –BM@KB)-based cells delivered a reversible capacity of 673.5 mAh g –1 after 300 cycles at 1 A g –1 at 30 °C with a capacity retention of 80%. Furthermore, high loading cells achieved high areal capacities of up to 14.43 mAh cm –2 . This study highlights the potential of SeS 2 as an outstanding cathode material for developing high-energy-density all-solid-state batteries (ASSBs).