Engineering Electronic Inductive Effect of Linker in Metal‐Organic Framework Glass Toward Fast‐Charging and Stable‐Cycling Quasi‐Solid‐State Lithium Metal Batteries

Abstract Metal‐organic frameworks (MOFs) have been corroborated as promising quasi‐solid‐state electrolytes (QSSEs) matrix relying on their structural and compositional traits, while low Li + conductivity ( σ Li + ) still afflicts their further advances due to intense constraints from anions and large ionic resistance from the grain boundary. Herein, a combination strategy of simultaneous electronic engineering of linker and vitrification is adopted to optimize σ Li + for MOF‐based QSSEs. The introduction of an electrophilic ─Cl substituent in benzimidazole linker compels the electron to deviate from Zn 2+ and modulates their charge distribution, which immobilizes bis(trifluoromethanesulfonyl)imide anions and thus boosts Li + transference number. Meanwhile, the vitrification endows ZIF‐62 with the elimination of boundary resistance for high ionic conductivity. Consequently, ─Cl‐substituted glassy ZIF‐62 containing Li salt (Cl‐Li‐G62) showcases a high σ Li + of 4.89 × 10 −4 S cm −1 at 25 °C. Impressively, Li metal batteries pair with LiFePO 4 cathode and Cl‐Li‐G62 present an initial capacity of 145.4 mAh g −1 with a decay rate of 0.006% at 1C, and a superior rate performance of 79.5 mAh g −1 at 5C. The work demonstrates the effectiveness of introducing electron‐withdrawing groups into MOF glass for enhancing σ Li + and offers a strategy to boost fast‐charging and stable cycling performance of MOF glass‐based quasi‐solid‐state lithium metal batteries.