In Situ Electrochemical Construction of Dual-Carbonyl Sites in 2D Covalent Organic Framework for Enhanced Sodium Storage

Abstract Covalent organic frameworks (COFs) are promising anodes for sodium-ion batteries, yet insufficient active sites and low utilization of these sites limit their applications. In this work, a carbonyl-enriched TRO-OTPA COF integrating alkyl ketone and quinone units was developed as a high-performance SIB anode. Electrochemical activation converts its phenolic groups into in situ benzoquinone sites, which synergize with intrinsic alkyl ketones to construct dual carbonyl redox centers, boosting sodium storage. As a result, the TRO-OTPA electrode delivers a high reversible capacity of 328 mAh g–1 at 0.05 A g–1, superior rate performance, and 86.5% capacity retention over 5000 cycles at 0.5 A g–1. This work reveals the role of electro-induced structural evolution and synergistic redox, guiding molecular design of multi-active-site organic electrodes.