In Situ Self‐Reconfiguration Induced Multifunctional Triple‐Gradient Artificial Interfacial Layer toward Long‐Life Zn‐Metal Anodes

Abstract Aqueous Zn‐ion batteries featuring with intrinsic safety and low cost are highly desirable for large‐scale energy storage, but the unstable Zn‐metal anode resulting from uncontrollable dendrite growth and grievous hydrogen evolution reaction (HER) shortens their cycle life. Herein, a feasible in situ self‐reconfiguration strategy is developed to generate triple‐gradient poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDDA‐TFSI)‐Zn₅(OH)₈Cl₂·H₂O‐Sn (PT‐ZHC‐Sn) artificial layer. The resulting triple‐gradient interface consists of the spherical top layer PT with cation confinement and H₂O inhibition, the dense intermediate layer ZHC nanosheet with Zn²⁺ conduction and electron shielding, and the bottom layer Znophilic Sn metal. The well‐designed triple‐gradient artificial interfacial layer synergistically facilitates rapid Zn²⁺ diffusion to regulate uniform Zn deposition and accelerates the desolvation process while suppressing HER. Consequently, the PT‐ZHC‐Sn@Zn symmetric cell achieves an ultralong lifespan over 6500 h at 0.5 mA cm⁻² for 0.5 mAh cm⁻². Furthermore, a full battery coupling with MnO₂ cathode exhibits a 17.2% increase in capacity retention compared with bare Zn anode after 1000 cycles. The in situ self‐reconfiguration strategy is also applied to prepare triple‐gradient PT‐ZHC‐In, and the assembled Zn//Cu cell operates steadily for over 8400 h while maintaining Coulombic efficiency of 99.6%. This work paves the way to designing multicomponent gradient interface for stable Zn‐metal anodes.