Multi‐level Zn²⁺‐Buffering Interphase Enabled by Hierarchical Nanostructure Engineering of Gel Polymers for Highly Reversible Zinc Metal Anode

The cycle life of aqueous zinc‐ion batteries (AZIBs) is hindered by the unstable Zn anode interface, causing uncontrolled dendrite growth and side reactions. Herein, for the first time, a hierarchical nanostructure‐engineered hydrogel interphase layer is developed via a facile and precisely controlled copolymerization‐induced microphase separation (CIMS) strategy, which enables multi‐level Zn 2+ ‐buffering to stabilize the Zn anode interface: 1) The nanoconfinement effect, combined with the hydrophobicity ofmethylacryloyloxypropyl cage‐type polyhedral oligomeric silsesquioxane (MP‐POSS), facilitates [Zn(H 2 O) 6 ] 2+ desolvation while blocking water and SO 4 2− penetration, achieving an optimal balance between enhanced Zn 2+ transport and minimized side reactions; 2) CIMS between polar comonomers and MP‐POSS creates hierarchical molecular clusters within the hydrogel. These self‐assembled domains homogenize Zn 2+ flux and reduce interfacial concentration polarization, realizing dendrite‐free Zn deposition. After modification, symmetric cells achieve exceptionally long lifespan exceeding 5500 h (1 mA cm −2 ) and 1500 h (10 mA cm −2 ). Asymmetric cell demonstrates an impressive Coulombic efficiency of 99.6% after 3600 cycles. MnO 2 and V 2 O 5 full cells retain 85.4% and 84.7% capacity retention after 1000 (1 A g −1 ) and 2000 (5 A g −1 ) cycles, respectively. This research unveils a novel multi‐level Zn 2+ ‐buffering mechanism based on gel polymer hierarchical nanostructure engineering and provides a feasible strategy for advancing grid‐scale AZIBs.