Metal Organic Framework (MOF-808) Incorporated Composite Solid Polymer Electrolyte for Stable All- Solid-State Lithium Batteries

Abstract All solid-state lithium-ion batteries (ASSBs) are emerging as promising candidates for power applications in electric vehicles and various energy storage systems, garnering significant research interest. However, enhancing the Li⁺ conductivity and solid polymer electrolyte (SPE) stability have been persistent challenges in the field. This work demonstrates a novel approach to fabricating a composite SPE with uniformly dispersed porous MOF-808 particles in a poly(ethylene oxide) (PEO) matrix, mixed with LiTFSI salt. The resulted composite SPE exhibits a 20-fold increase in ion conductivity (9.7×10⁻ ⁴ S cm⁻¹ at 60°C), and an expanded electrochemical window up to 4.8 V. Assembled ASSB with LiFePO₄ cathodes and Li metal anodes under 50 MPa pressure show good specific capacity (140.3 mAh g⁻¹) and excellent cycling stability (93.5% capacity retention). This composite SPE has also demonstrated excellent compatibility with the high-voltage cathode material NCM811, exhibiting superior electrochemical stability. Results of this work highlight the use of MOF materials in SPE, advancing the development of next-generation solid-state batteries.