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

Abstract

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 Zn²⁺-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(H₂O)₆]²⁺ desolvation while blocking water and SO₄ ^2- penetration, achieving an optimal balance between enhanced Zn²⁺ 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 Zn²⁺ 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. MnO₂ and V₂O₅ 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 Zn²⁺-buffering mechanism based on gel polymer hierarchical nanostructure engineering and provides a feasible strategy for advancing grid-scale AZIBs.