From Glass Waste to High‐Performance Solid Composite Electrolytes for Sustainable Solid‐State Lithium Batteries

ABSTRACT Solid‐state lithium batteries (SSLBs) are promising next‐generation energy storage devices, but their widespread deployment is largely hampered by costly, resource‐intensive solid electrolytes. Here we report a low‐cost, high‐performance, and sustainable solid composite electrolyte (SCE) membrane that comprises commercial high‐alkali glass fiber (GF) separators as scaffolds for in situ polymerization of the PEGDA/LiTFSI/FEC matrix. The alkali‐doped silicate framework in GF provides abundant Lewis acid‐base sites that promote lithium salt dissociation and enhance directional Li + transport. The resulting GF‐SCE exhibits an ionic conductivity of 5.89 × 10 −4 S cm −1 at 25°C, a wide electrochemical stability window up to 5.0 V, and extensive dendrite‐free cycling, enabling the formation of a stable LiF‐rich solid‐electrolyte interphase. When GF‐SCE is used in a cell containing high‐Ni LiNi 0.96 Co 0.03 Mn 0.01 O 2 cathode and Li metal anode, a large specific capacity of 253.6 mAh g −1 and stable cycling are achieved. Techno‐economic analyses show that the production cost of GF‐SCE membranes is only $8.98–$17.15 m −2 via solvent‐free roll‐to‐roll processing with earth‐abundant precursors, favorably competitive relative to other inorganic electrolyte counterparts. By combining high electrochemical performance, potential scalability, and favorable recyclability, the glass‐fiber‐based SCEs reported in this work offer a practical, cost‐effective pathway toward circular and high‐voltage solid‐state lithium batteries.