Sandwich structured NASICON-type electrolyte matched with sulfurized polyacrylonitrile cathode for high performance solid-state lithium-sulfur batteries

All-solid-state lithium-sulfur batteries show increasing potential for practical applications in portable electronic devices and electric vehicles due to their high energy density, low cost, and environmental friendliness. However, the large interface impedance of solid-state lithium-sulfur batteries leads to low capacity and short cycle life. In this study, a hierarchical design of sandwiched NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid-state electrolyte with surface modification by a solid polymer electrolyte (SPE) is proposed for high-performance lithium-sulfur batteries. Due to the unique hierarchical structure of the solid electrolyte in which SPE (PEO: LiTFSI = 8:1) layer is coated on NASICON solid electrolyte surface, the direct contact between lithium metal anode and LATP solid electrolyte can be avoided, and the improved interfacial property between the electrolyte and electrodes can be achieved. As a result, the as-prepared solid-state Li|SPE-LATP-SPE|Li symmetrical cell exhibits a stable cycling performance. Moreover, solid-state lithium-sulfurized polyacrylonitrile (SPAN) battery based on such electrolyte delivers an ultrahigh initial discharge capacity of 1793 mAh g−1 at 75 °C with high coulombic efficiencies and stable cycling performance. The present work provides a creative design of battery configuration for manufacturing high-performance and safe solid-state lithium-sulfur batteries.