Host‐Guest Recognition‐Enabled Covalent Organic Framework Artificial Interphase for Anion Regulation and Selective Li + Transport in Lithium Metal Batteries

Abstract

ABSTRACT The practical application of lithium metal batteries is severely restricted by dendritic lithium growth and the continuous evolution of unstable solid electrolyte interphases, both of which originate from sluggish Li + desolvation kinetics. Herein, a host‐guest recognition‐enabled covalent organic framework is developed to regulate interfacial ion migration. By nanoconfined copolymerization of ionic‐liquid monomers within the channels, multi‐cation molecular chains (MCMC) are integrated into the framework to construct a DVA‐COF‐MCMC interphase with selective Li + transport capability. The cationic recognition sites selectively immobilize bis(trifluoromethanesulfonyl)imide anions through strong host‐guest interactions, disrupting Li + ‐anion coordination and establishing Li + ‐exclusive transport pathways. Theoretical calculations and in situ characterizations reveal that the recognition‐driven ion regulation redistributes the local charge environment, lowers the Li + dissociation energy barrier, and promotes the formation of a homogeneous LiF‐rich solid electrolyte interphase. Consequently, the modified lithium anode delivers a high Li + transference number (0.81), a wide electrochemical stability window (4.8 V), and stable Li plating/stripping (1200 h). Full cells paired with LiFePO 4 and LiNi 0.9 Co 0.05 Mn 0.05 O 2 cathodes exhibit outstanding rate capability. This work transforms covalent organic framework interfacial engineering from passive channel confinement to active channel recognition, offering a new paradigm for high‐performance lithium metal batteries (LMBs).