In Situ Constructed Zn ₃ N ₂ ‐Enriched Hybrid Solid Electrolyte Interphase Enables Highly Efficient Zinc Deposition Kinetics for Ultra‐Stable Zinc‐Iodine Batteries

ABSTRACT Rechargeable aqueous zinc‐iodine (Zn‐I ₂ ) batteries face severe challenges, primarily stemming from the interfacial incompatibility between the Zn anode and electrolyte, complex side reactions, and the aggravated polyiodide shuttle effect induced by sluggish charge‐transfer kinetics. To mitigate these issues, this work introduces copper hexadecafluorophthalocyanine (FCP) as a novel electrolyte additive to in situ construct a mechanically robust, Zn ₃ N ₂ ‐rich inorganic–organic hybrid solid electrolyte interphase (SEI). This unique SEI, featuring highly ion‐conductive Zn ₃ N ₂ , not only accelerates Zn ²⁺ migration but also leverages the macrocyclic conjugated structure of FCP to generate a delocalized electric field, facilitating the desolvation of hydrated Zn ²⁺ . Additionally, the planar π‐conjugated backbone promotes in‐plane electron transport, further optimizing interfacial kinetics. Furthermore, FCP molecules preferentially adsorb onto the Zn surface, guiding uniform Zn deposition and improving interfacial stability. As a result, the assembled symmetric cells achieve ultrastable cycling for over 6000 cycles at ultrahigh current densities (20 and 50 mA cm ⁻² ), while the Zn anode exhibits an ultrahigh Coulombic efficiency of 98.7% and exceptional reversibility in plating/stripping. A Zn‐I ₂ full battery also delivers outstanding long‐term cycling stability, retaining 80.9% capacity after 65000 cycles at an ultrahigh rate of 50 C.