Tunnel‐Framework Interphase Driving Rapid Zn ²⁺ Diffusion for Long‐Life Zn Metal Anodes

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) are presently attracting considerable interest for large‐scale energy storage owing to their low cost and high safety. Nevertheless, technical issues associated with aqueous electrolytes, including the hydrogen evolution reaction (HER), corrosion, and diffusion‐related dendrite growth, severely hinder their commercialization. Herein, a stable 3D tunnel framework (denoted as ASN) consisting of a Si 3 N 4 layer is constructed on bare Zn foil electrodes. The framework induces a homogeneous zinc ion flux and enables fast diffusion of zinc ions, while isolating the Zn metal surface from direct contact with water, thereby suppressing parasitic reactions. Density functional theory calculations and x‐ray absorption fine structure results reveal that Si─N sites within the coating facilitate the in‐tunnel hopping of Zn 2+ . Scanning electron microscope (SEM) images reveal uniform Zn nucleation and growth owing to the rapid diffusion accelerated by the tunnel framework, while in situ Raman spectroscopy reveals mitigated concentration polarization. As a result, the ASN@Zn symmetric cell exhibits an extended lifespan of more than 1800 h at 3 mA cm −2 . The ASN@Zn anode reaches a high average coulombic efficiency of 99.89% over 1500 cycles. Moreover, the modified full cell with calcium vanadate cathode exhibits stable cycling for ∼10 000 cycles at 14 A g −1 .