Optimizing one-dimensional ion conduction and interface stability in PEO electrolytes with PAN-coated palygorskite fibers

The development of solid-state electrolytes with high ionic conductivity and wide electrochemical window is crucial for the advancement of lithium batteries. In this work, we introduce a polyethylene oxide (PEO)-based electrolyte hybridized with the polyacrylonitrile coated lithiated palygorskite fibers (Li-Pal@PAN) to enhance ionic conductivity and electrochemical stability. First, the Li-Pal@PAN serves as a one-dimensional lithium-ion conduction pathway in the solid-state electrolyte with a low interfacial energy barrier for Li + transfer. Then, it facilitates the formation of a composite solid electrolyte interface (SEI) that contains Li 3 N, effectively mitigating side reactions between the lithium metal anode and the electrolyte. As a result, the Li-Pal@PAN enhances the oxidative stability of the PEO-based electrolyte, increasing its oxidation potential to 4.9 V. Electrochemical characterization further demonstrates that a Li||Li symmetric cell using the PEO/Li-Pal@PAN composite exhibits stable cycling performance over 1000 h at a current density of 0.1 mA cm −2 . Moreover, all-solid-state lithium metal batteries utilizing a high-voltage ternary cathode (LiNi 0.6 Mn 0.2 Co 0.2 O 2 , NCM622) deliver a high-rate capacity of 117 mAh g −1  at 0.3C. These results underscore the significant potential of PEO/Li-Pal@PAN composites in improving the performance, stability, and longevity of all-solid-state Li metal batteries, offering a promising pathway for their application in advanced energy storage system.