Overcoming the conversion reaction limitation with a 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 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 lithiated CoS₂ (LiCoS₂) improves the interfacial Li⁺ transport kinetics and facilitates the complete conversion from S to Li₂S with a lower energy barrier. Consequently, ASSLSBs with the S/CoS₂@rGO cathode achieve substantially enhanced cathode utilization ratios (>97%) with high discharge capacity (>1546 mAh g⁻¹). Moreover, these batteries exhibit excellent cycling stability over 500 cycles at 0.5 A g⁻¹. This strategy offers novel guidelines for the rational design of high-capacity conversion cathodes.