An Extended <i>π</i> ‐Conjugated Porous Polymer with Dense Multiple Redox Centers Boosts High‐Efficiency Sodium‐Ion Storage

Abstract Developing new organic electrodes with high specific capacities, fast reaction kinetics, and superior rate capabilities for high‐performance sodium‐ion batteries remains a critical challenge. Integrating dense multiple redox centers and extensive π ‐conjugated frameworks into one system can be a promising strategy. Here, a polyimide‐based conjugated porous polymer (namely HAT‐DAAQ) is designed with large π ‐conjugation and dense active sites for efficient Na + storage. As the connecting ligand, hexaazatriphenylenehexacarboxylic acid trianhydride (HAT‐T) provides highly dense C═N and C═O active sites and stable planar conjugated architectures, while 2,6‐diaminoanthraquinone (DAAQ) introduces additional C═O electroactive centers and enables their rational distribution across the molecular skeleton. Demonstrated as a high‐performance organic electrode, HAT‐DAAQ delivers a reversible discharge capacity of 441 mAh g −1 at 0.1 C with almost full utilization of active sites and an excellent rate capability of 327.4 mAh g −1 at 5.0 C. Assembled with Na 3 V 2 (PO 4 ) 3 cathode, the full battery maintains an energy density of 122 Wh kg −1 total mass , superior to most reported polyimide‐based batteries. Additionally, density functional theory calculations and spectroscopic experiments elucidate a 24‐electron storage mechanism induced by C═N and C═O redox reactions. This investigation underscores the pivotal role of molecular‐level structural regulation in achieving efficient and sustainable Na + storage.