Carbonyl‐Rich Polyimide Covalent Organic Frameworks as Anode Coating for Uniform Sodium Deposition

ABSTRACT Two‐dimensional covalent organic frameworks (2D COFs), by virtue of their structural diversity, high specific surface area, and facile functionalization, have emerged as a promising anode coating for sodium metal batteries (SMBs). Herein, we report two polyimide COFs (TATT‐NTCDA‑COF and TATT‐PMDA‑COF) constructed from isocyanurate‐based amine building blocks, which feature profuse ion‐binding active sites and a robust, ordered framework, thereby significantly enhancing ion transport, fostering uniform sodium deposition, and suppressing dendrite growth. Benefiting from this unique design and its reliable stability, the symmetric cell based on TATT‐NTCDA‑COF operates stably for over 1200 h at 0.1 mA cm −2 . When assembled into a full cell with a commercial Na 3 V 2 (PO 4 ) 3 (NVP) cathode, it delivers an initial discharge capacity of 107.4 mAh g −1 , retains 9.3% capacity after 800 cycles at 1 C, and maintains over 90% capacity retention even after 1390 cycles at 5 C and 750 cycles at 10 C. Thus, the rational design of carbonyl‐rich 2D COFs is of great significance for the construction of artificial anode coatings for SMBs.