Multifunctional Core‐Shell Structured Interface Layer Regulate Zn Deposition Behavior and Anti‐Polyiodide Ions Towards Ultralong‐Life Zn‐I 2 Battery

ABSTRACT Zinc‐iodine (Zn‐I 2 ) batteries have attracted extensive attention in energy storage domains on account of their rich natural reserves, higher voltage platforms, and non‐ion in(de)intercalation mechanism. Yet their practical utilization is restricted by the Zn dendrites growth and side reactions, as well as serious polyiodides dissolution and shuttling. Herein, a core‐shell structured InHCF@ZIF‐8 (IHZ) was designed and synthesized via electrostatic self‐assembly, serving as a multifunctional interface layer for Zn anodes. Driven by the dual coordination mechanism of InHCF and ZIF‐8, IHZ exhibits excellent Zn affinity and a high hydrogen evolution overpotential, which not only induces uniform Zn deposition but also realizes the homogeneous distribution of local electric field and Zn 2+ flux. Furthermore, the strong adsorption of IHZ on the Zn (002) plane directs the horizontal deposition of Zn, thus effectively suppressing dendrite nucleation and growth. Meanwhile, the self‐discharge effect is mitigated via electrostatic repulsion toward I 3 − . As a result, symmetric cells employing the Zn@IHZ anode deliver an ultralong cycle life of 6490 h at 0.5 mA cm −2 and 0.5 mAh cm −2 . The Zn@IHZ anode endows the Zn‐I 2 battery with a remarkable capacity, excellent rate capability, and an ultralong lifespan over 14800 cycles.