Topological Crosslinker Design Regulates Interfacial and Active Species Transport in Zinc‐Iodine Batteries

Abstract

ABSTRACT Aqueous zinc‐ion batteries (ZIBs) are limited by interfacial instability and an intrinsic trade‐off between mechanical strength and ionic conductivity in polymer gel electrolytes (PGEs), restricting their cycling durability and practical application. Here, we report a topology‐regulated crosslinker strategy that redefines crosslinkers from passive structural components to active regulators of ion transport and interfacial chemistry. A tetra‐armed poly(2‐ethyl‐2‐oxazoline) (4‐PEtOx) crosslinker is integrated into a zwitterionic network to construct a hydrogel electrolyte (4‐PVEX). The unique molecular topology establishes a dense yet dynamic hydrogen‐bonding framework, enabling continuous Zn 2+ transport pathways while maintaining high mechanical strength. As a result, 4‐PVEX stabilizes the Zn/electrolyte interface, promotes uniform dendrite‐free Zn deposition, suppresses parasitic reactions, and effectively immobilizes polyiodide species while accelerating iodine redox kinetics. Zn||Zn symmetric cell exhibits stable cycling for over 2700 h, and Zn||Cu cell delivers an average Coulombic efficiency of 99.7% over 1000 cycles. Moreover, Zn||I 2 full cell retains 90% of its initial capacity after 10 000 cycles at 10 C. This work demonstrates molecular topology as a powerful design dimension for advanced gel electrolytes and provides new insights into interfacial and transport regulation in aqueous metal batteries.