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Due to the high abundance of their components, low cost, and high safety, zinc‐based batteries open up new vistas for large‐scale energy storage. However, their stability, lifetime, and reversibility are impaired by passivation and dendrite growth of the Zn anode. Here, this challenge is circumvented by an iodine post‐functionalized zeolitic imidazolate framework‐90 (ZIF‐90‐I) additive, in which the polycation absorbed on Zn anode can regulate solid–electrolyte interphase (SEI) formation in the 1 m Zn(TFSI)2 electrolyte and induce Zn2+ uniform deposition. Moreover, the I3−/I− redox can rejuvenate dead Zn and inhibit dendrites. With the ZIF‐90‐I additive, Zn plating/stripping at 99.5% Coulombic efficiency for 120 cycles is obtained in Zn||Ti cells at 20 mA cm−2/1 mAh cm−2. In addition, Zn||Zn cells show steady cycling for 1200 h at 5 mA cm−2/1 mAh cm−2 with stable overpotentials. The utilization rate of Zn reaches up to 68.6%. In situ optical microscopy reveals smooth, uniform Zn plating, and the Zn‐rejuvenated function from the I3−/I− redox couple. The refreshed SEI with the increase of Zn‐rich complexes, and nitrides from adsorbed polycations, are uniform and ZnF2‐rich in the Zn(TFSI)2 + ZIF‐90‐I electrolyte. The full Zn||air cells in Zn(TFSI)2 + ZIF‐90‐I electrolyte exhibit excellent cycling stability with stable polarization voltage at 0.1 mA/0.05 mAh cm−2. [ABSTRACT FROM AUTHOR]

Electroactive organic electrode materials exhibit remarkable potential in aqueous zinc ion batteries (AZIBs) due to their abundant availability, customizable structures, sustainability, and high reversibility. However, the research on AZIBs has predominantly concentrated on unraveling the storage mechanism of zinc cations, often neglecting the significance of anions in this regard. Herein, bipolar poly(thionine) is synthesized by a simple and efficient polymerization reaction, and the kinetics of different anions are investigated using poly(thionine) as the cathode of AZIBs. Notably, poly(thionine) is a bipolar organic polymer electrode material and exhibits enhanced stability in aqueous solutions compared to thionine monomers. Kinetic analysis reveals that ClO 4 - exhibits the fastest kinetics among SO 4 2- , Cl - , and OTF - , demonstrating excellent rate performance (109 mAh g -1 @ 0.5 A g -1 and 92 mAh g -1 @ 20 A g -1 ). Mechanism studies reveal that the poly(thionine) cathode facilitates the co-storage of both anions and cations in Zn(ClO 4 ) 2 . Furthermore, the lower electrostatic potential of ClO 4 - influences the strength of hydrogen bonding with water molecules, thereby enhancing the overall kinetics in aqueous electrolytes. This work provides an effective strategy for synthesizing high-quality organic materials and offers new insights into the kinetic behavior of anions in AZIBs., (© 2024 Wiley‐VCH GmbH.)