Polar-rich-group triazine-based covalent organic frameworks modified separators with de-solvation effect enables uniform Li deposition for stable lithium-metal anode

The uneven deposition and high reactivity of lithium-metal anode (LMA) lead to uncontrollable dendrite growth, low Coulombic efficiency, and safety concerns, hindering their commercialization. Here, a representative polar-rich-group triazine-based covalent organic framework (COF-TzDha) with a desolvation effect is designed as an interlayer for stable, dendrite-free LMA. The abundant triazine rings in COFTzDha as a donor effectively attract lithium ions, while the one-dimensional nanopore structure facilitates lithium-ion migration. The periodic arrangement of polar groups (-OH) in the backbone interacts with electrolyte components (DOL, DME, TFSI- ) to form a hydrogen bonding network that slows solvent molecules transport. Therefore, COF-TzDha effectively desolvates lithium ions from the solvent sheath, promoting uniform lithium ion flux and Li plating/stripping. Theoretical calculations verify that COFTzDha with abundant adsorption sites and strong adsorption energy facilitates lithium ion desolvation. Consequently, the introduction of COF-TzDha obtains a high ion mobility (0.75). The Li| COF@PP|Li symmetric cell cycles stably for over 1200 h at 4 mA cm-2 /4.0 mA h cm-2 . The Li|COF@PP| LiFePO4 full cell also displays highly stable cycling performance with 600 cycles (75.5% capacity retention, similar to 100% Coulombic efficiency) at 1 C. This work verifies an effective strategy for inducing uniform Li deposition and achieving dendrite-free, stable LMA using a polar-rich-group COF interlayer with a desolvation effect. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.