Polyamine Compound with High‐Density N‐H Proton Arrays Enables High‐Loading and Long Lifespan Zinc‐Iodine Batteries

ABSTRACT Aqueous zinc‐iodine (Zn‐I ₂ ) batteries, despite their cost‐effectiveness and safety, are plagued by zinc anode corrosion and the polyiodide shuttle effect. Herein, trace tetraethylenepentamine (TEP), with a high‐density N‐H proton array, is employed to regulate the running environment of Zn‐I ₂ batteries, which suppresses anode corrosion and polyiodide formation, enabling long‐term cycling under high‐loading conditions. For the zinc anode, TEP's high‐density N‐H array facilitates preferential surface adsorption, optimizing the interfacial Helmholtz layer. Rich in lone‐pair electrons, its ‐NH ₂ and ‐NH‐ groups as Lewis bases coordinate with Zn ²⁺ ions to regulate interfacial ion dynamics, enabling dendrite‐free Zn deposition. For the iodine cathode, TEP coordinates with I ₂ via the lone pair electrons of N atoms and forms strong electrostatic hydrogen bonds between H protons and I ⁻ , synergistically suppressing polyiodides formation, thereby enhancing the utilization of the iodine cathode. Consequently, TEP enables the Zn||Zn battery to achieve a stable cycling for over 2333 h (1 mA cm ⁻² , 1 mAh cm ⁻² ). The Zn‐I ₂ battery with a high iodine loading (15.9 mg cm ⁻² ) retains 91.3% capacity after 8900 cycles. This study demonstrates that incorporating a trace amount of TEP provides a new insight into the development of sustainable, long‐life Zn‐I ₂ batteries.