In Situ‐Engineered MOF/Polymer Hybrid Electrolyte With 3D Continuous Ion Channels for High‐Voltage and Thermal‐Resistant Lithium Metal Batteries

ABSTRACT Composite quasi‐solid‐state electrolytes are pivotal for enabling high‐energy‐density lithium metal batteries (LMBs), yet their practical application is hindered by discontinuous ion transport, poor interfacial stability, and limited high‐voltage endurance. Here, a universal in situ growth strategy is developed to construct a metal‐organic framework (MOF)/polymer composite electrolyte (ZCPSE) with hierarchically ordered ion‐conducting networks. The ultra‐uniform MOF nanoparticles (e.g., ZIF‐8) are anchored onto polymer nanofibers, creating abundant nanopores and Lewis acid sites that synergistically enhance Li⁺ transport and oxidative stability. The resulting ZCPSE exhibits unprecedented ionic conductivity (0.46 mS cm −1 at 25°C), a wide electrochemical window (5.15 V vs. Li/Li + ), and exceptional mechanical strength (151.2 MPa, 4× higher than pristine polymer membrane). Theoretical simulations reveal that the 3D continuous MOF/polymer interface facilitates rapid Li + dissociation and uniform flux distribution, endowing ZCPSE with a high Li + transference number (0.74) and dendrite‐free Li plating/stripping (2000 h in Li|Li symmetric cells). Practical applicability is demonstrated in Li|LiFePO 4 cells (stable cycling at 25°C–100°C) and high‐voltage Li|LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cells (4.5 V, 100 cycles with 99.2% capacity retention). This study provides a paradigm for designing MOF‐based hybrid electrolytes with simultaneous ionic, mechanical, and interfacial optimization, paving the way for safe and high‐energy LMBs.