A Large‐Scale Fabrication of Flexible, Ultrathin, and Robust Solid Electrolyte for Solid‐State Lithium‐Sulfur Batteries

Abstract All‐solid‐state lithium metal batteries (ASSLMBs) are considered as the most promising candidates for the next‐generation high‐safety batteries. To achieve high energy density in ASSLMBs, it is essential that the solid‐state electrolytes (SSEs) are lightweight, thin, and possess superior electrochemical stability. In this study, a feasible and scalable fabrication approach to construct 3D supporting skeleton using an electro‐blown spinning technique is proposed. This skeleton not only enhances the mechanical strength but also hinders the migration of Li‐salt anions, improving the lithium‐ion transference number of the SSE. This provides a homogeneous distribution of Li‐ion flux and local current density, promoting uniform Li deposition. As a result, based on the mechanically robust and thin SSEs, the Li symmetric cells show outstanding Li plating/stripping reversibility. Besides, a stable interface contact between SSE and Li anode has been established with the formation of an F‐enriched solid electrolyte interface layer. The solid‐state Li|sulfurized polyacrylonitrile (Li|SPAN) cell achieves a capacity retention ratio of 94.0% after 350 cycles at 0.5 C. Also, the high‐voltage Li|LCO cell shows a capacity retention of 92.4% at 0.5 C after 500 cycles. This fabrication approach for SSEs is applicable for commercially large‐scale production and application in high‐energy‐density and high‐safety ASSLMBs.