LiX Zeolites Hybrid Polyethylene Oxide-Based Polymer Electrolyte for Practical Lithium Metal Batteries

Polymer solid electrolytes (PSEs) serve as safer alternatives to liquid electrolytes for lithium metal batteries (LMBs) owing to their enhanced thermal and electrochemical stability. However, the practical application of PSEs is constrained by low ionic conductivity and suboptimal electrochemical performance. In this study, we develop a composite solid polymer electrolyte (CSPE) by incorporating LiX zeolites into a polyethylene oxide (PEO) matrix to create Li⁺ transport channels with low curvature, thereby enhancing Li⁺ mobility. The introduction of LiX significantly improves the electrochemical properties of the CSPE, achieving a high ionic conductivity of 8.5 × 10⁻⁴ S cm⁻¹ at 60°C, and a broadened electrochemical stability window of 4.6 V. As a result, Li | |LiFePO₄ all-solid-state cells exhibit excellent cycling performance, retaining 132.8 mAh g⁻¹ with 85.71% capacity retention after 800 cycles at 1C. Furthermore, all-solid-state pouch cells assembled with LiX-based CSPEs maintain stable operation even under mechanical abuse conditions (e.g., folding, twisting, and cutting), highlighting their potential for safe and flexible energy storage applications.