Work

Coupling Iodine Conversion and Zinc Ion Transport via Molecular Catalysis for Long‐Life Zinc‐Iodine Batteries

Year: 2026

Type: article

Abstract: ABSTRACT Zinc–iodine (Zn–I 2 ) batteries are attractive for low‐cost and scalable energy storage owing to their rapid iodine redox and high theoretical capacity. However, their practical application is severely limited by polyiodide shuttling and interfacial mass‐transport imbalance, where polyiodide immobilization and Zn 2+ accessibility are difficult to reconcile for continuous redox compensation, especially under high‐rate conditions. Here, we address this adsorption–transport conflict by screening a series of metalated tetrakis(4‐carboxyphenyl) porphyrin molecular catalysts and identifying iron (III) meso‐tetrakis (4‐carboxyphenyl) porphyrin (Fe–TCPP) as a unified interfacial regulator catalyst. The Fe–N 4 center provides moderate polyiodide binding, thereby stabilizing iodide intermediates without inducing interfacial passivation. Meanwhile, peripheral carboxyphenyl groups create a zincophilic microenvironment that promotes Zn 2+ accessibility and local ion compensation. This coordinated regulation synchronizes electron transfer and ion redistribution, thereby sustaining reversible iodine redox while avoiding transport blockage. As a result, the Fe–TCPP‐regulated iodine cathode delivers a specific capacity of 178 mAh g −1 and sustains 50 000 cycles at 5 A g −1 . Moreover, a pouch cell with a high iodine loading of 22 mg cm −2 operates stably for more than 1300 cycles. This work establishes a molecular‐catalytic framework for the simultaneous regulation of redox‐intermediate adsorption–conversion and ionic transport in aqueous batteries involving soluble redox species.

Source: Advanced Materials

DOI: 10.1002/adma.75537