Unveiling Dual-Interface Coordination Orchestration for Durable Aqueous Zinc–Iodine Pouch Cells with Four-Electron Chemistry

Electrolyte additive engineering is regarded as an effective strategy for dual-interface optimization in four-electron aqueous zinc-iodine batteries (AZIBs). However, realizing durable Ah-level AZIBs with industrial-grade parameters (≥10 mg cm-2 I2 cathode mass loading, ≥5 mAh cm-2 Zn anode areal capacity) remains a significant hurdle. Here, we compare various nitrogen-containing cationic ligands to evaluate their synergistic regulation on iodine immobilization and Zn nucleation. This screening successfully establishes N-methylimidazolium chloride (MImCl) as a premier electrolyte additive for stabilizing dual-interface coordination. Upon discharging, the adsorption of MIm+ on the I2 cathode enables electrostatic binding with polyiodides and ICl2-. This interaction not only suppresses the polyiodide shuttle but also shields the I+ species from hydrolysis, promoting a robust and reversible four-electron I-/I0/I+ redox chemistry at elevated I2 mass loading. On the Zn anode, MIm+ preferentially adsorbs onto its surface during charging, accelerating Zn2+ deposition kinetics for dendrite suppression while passivating parasitic reactions, realizing uniform large-capacity Zn plating/stripping. As a result, the engineered 1.4 Ah four-electron Zn||I2 pouch cells achieve an excellent cyclability of 800 cycles and an ultrahigh cathode-mass-specific energy density of 455 Wh kg-1, surpassing most aqueous Zn-based systems in the Ah-class regime.