Metal-organic framework-driven composite polymer electrolytes with high lithium mobility for high-safety and...

Solid-state lithium batteries (SSLBs) have attracted much attention due to their high energy density and enhanced safety. However, achieving high ionic conductivity and good interfacial compatibility of solid-state electrolytes has been a challenge in the field. Herein, we developed multifunctional ultrathin composite polymer electrolytes (CPEs) consisting of uniformly dispersed metal-organic frameworks (MOF) in a polymer matrix and LiTFSI filled within the MOF channels. These MOF nanochannels boosted lithium salt dissociation and created continuous channels for rapid Li⁺ transport, which enabling uniform Li⁺ flux to ensure good interfacial compatibility. The resulting CPEs exhibited excellent ionic conductivity (∼3 × 10^-4 S cm^-1 at room temperature), high Li⁺ transference number (up to 0.9), and wide electrochemical window (4.9 V). Leveraging these advantages, the Li/CPEs/Li symmetric battery demonstrated exceptional cyclability of over 1500 h, and the LiFePO₄/CPEs/Li battery showed high rate performance (103 mAh g^-1 at 5C) and excellent cycling stability (94.6 % capacity retention after 300 cycles at 1C). Furthermore, an Ah-level pouch battery demonstrates an impressive electrochemical performance (702 mAh after 200 cycles), representing the current state-of-the-art level of MOF-based solid-state batteries. This research provides a simplistic yet effective strategy for developing of MOF-based CPEs, which will greatly facilitate the development of next-generation SSLBs.