Exploring the concordant solid-state electrolytes for all-solid-state lithium-sulfur batteries

The design of composite sulfur cathode plays a critical role in determining the physical and (electro)chemical properties of all-solid-state lithium-sulfur batteries (ASSLSBs) owing to the intrinsic electrochemical inertia of sulfur. However, the composition especially the selection of solid-state electrolyte in the composite sulfur cathode to boost the electrochemical performance is barely studied. Herein, by comparing three typical sulfide solid-state electrolytes, we reveal the excellent compatibility between the sulfide electrolyte (Li7P3S11) and the sulfur cathode. The ASSLSBs based on Li7P3S11 electrolytes demonstrate fast reaction kinetics and high electrochemical stability, which can contribute to (electro)chemical congruency. Further physical and chemical characterizations of the composite sulfur cathode confirm the excellent compatibility between sulfur and the Li7P3S11 electrolytes. These findings provide guidance for developing advanced solid-state electrolytes for high-energy-density ASSLSBs.