All-Solid-State Lithium–Sulfur Batteries with Robust Interphases by Utilizing Elastomeric Polymer-in-Salt Electrolytes

All-solid-state lithium–sulfur (Li–S) batteries have emerged as one of the most promising alternative energy storage solutions ascribed to their potentials of high energy density, cost-effectiveness, and enhanced safety. Herein, elastomeric polymer-in-salt electrolytes (PISEs) have been developed by incorporation of highly dielectric and curable cyclic carbonate pendent groups into the polyether backbone to fabricate sulfurized polyacrylonitrile (SPAN)/Li batteries. The PISEs with an intrinsic saturation of the coordination sites exhibit effective inhibitions of the dissolution of lithium polysulfides and the growth of lithium dendrites and show favorable compatibility with both the SPAN cathode and lithium metal anode. The robust LiF-rich interphases formed between the electrodes and the PISEs are capable of effectively passivating the electrodes and accommodating their volume expansion, enabling the all-solid-sate SPAN/PISE/Li batteries with a high specific capacity of ∼1300 mAh gsulfur–1 and long-term cycling stability (over 4 months) at ambient temperature. This work provides a strategic framework for the design of high-performance polymer-based all-solid-state Li–S batteries.