Overcoming the Conversion Reaction Limitation with Dual-phase Sulfide-based Cathode for All-Solid-State Lithium-Sulfur Batteries

Abstract

Rechargeable all-solid-state lithium-sulfur batteries (ASSLSBs) have been garnering increasing attention due to their anticipated high safety and specific energy. However, the limited kinetics of solid-solid conversion reactions pose challenges in attaining high sulfur utilization. Herein, a dual-phase sulfide-based cathode (S/CoS2@rGO) is designed and implemented to ameliorate the issue of insufficient sulfur conversion through pre-embedding active sites. Experiments illustrate that the lithiated CoS2 (LiCoS2) will suppress the irreversible decomposition of electrolyte with improved Li+ transport kinetics and facilitate the complete conversion from S to Li₂S with lower energy barrier. Consequently, the ASSLSBs with S/CoS2@rGO cathode achieves substantially enhanced cathode utilization ratios (>97%) with high discharge capacity (>1546 mAh g–1). Moreover, these batteries exhibit excellent cycling stability over 200 cycles at 0.5 A g–1. The strategy offers novel guidelines for the rational design of high-capacity conversion cathodes.