Regulating Reversible Zn Deposition via a 2D Metal–Organic Framework‐Laden Hydrogel Electrolyte

Abstract The practical deployment of aqueous Zn‐ion batteries (AZIBs) is impeded by dendritic growth and parasitic side reactions of Zn anodes, which severely compromise reversibility and cycle stability. Herein, a hydrogel electrolyte (HE) is reported integrated with a 2D porphyrin‐based metal–organic framework (MOF) as a multifunctional filler to address these issues. The incorporation of the 2D MOF not only reinforces the mechanical integrity and enhances the ionic conductivity (14.87 mS cm ⁻¹ ) of the hydrogel matrix, but also serves a critical interfacial role. During cycling, the MOF nanosheets spontaneously adsorb at the Zn‐electrolyte interface, where porphyrin ligands with four nitrogen donor sites effectively capture Zn ²⁺ ions to facilitate a uniform Zn nucleation. Moreover, the MOF‐derived interphase suppresses dendrite formation and mitigates interfacial side reactions, thereby significantly improving the reversibility and durability of Zn anodes. As a result, the MOF‐laden HE enables Zn anodes with a high average Coulombic efficiency of 98.8% in the first 20 cycles, prolonged plating/stripping stability over 3000 h, and a high critical current density of 12 mA cm ⁻² . Furthermore, full cells coupled with a vanadium‐based cathode exhibit excellent cycling performance, achieving 78% capacity retention over 2000 cycles at 1 A g ⁻¹ .