Molecular‐Tailored Ultrathin Hydrophobic Interphases for High‐Stable Zinc Metal Anodes

ABSTRACT The Zn electrode interface is highly susceptible to the uncontrollable growth of Zn dendrites and severe parasitic reactions, which severely limit the practical application of aqueous zinc‐ion batteries (AZIBs). Developing stable interfacial layers is therefore crucial for improving the cycling stability of Zn metal anodes. In this work, by systematically comparing the effects of alkyl small molecules with different backbone chain lengths and terminal group distributions on the surface coverage and ordering of hydrophobic interfacial layers, the highly ordered self‐assembled monolayers (SAMs) based on 1‐fluorooctane (FT) are successfully constructed on the Zn anode. Electrochemical measurements further reveal that these monolayers facilitate the rapid desolvation of [Zn(H ₂ O) ₆ ] ²⁺ , guide uniform Zn deposition, and effectively suppress interfacial side reactions. As a consequence, a dendrite‐free and highly reversible FT–Zn anode is achieved, delivering an ultralong lifespan (exceeding 3200 h at 1.0 mA cm ⁻² ), a high Coulombic efficiency (99.71% after 1600 cycles), and excellent full‐cell capacity retention (83.4% after 1000 cycles). Through precise molecular structure regulation, this work demonstrates the controllable construction of an ultrathin hydrophobic self‐assembled interfacial layer, expanding a new strategy for developing highly reversible and stable Zn metal anodes and offering significant implications for accelerating the practical application and commercialization of AZIBs in large‐scale energy storage systems.