Zinc metal is an ideal anode for aqueous zinc-ion batteries (AZIBs) due to its high theoretical capacity and inherent safety. However, its practical application is hindered by dendrite growth and side reactions at the zinc anode/electrolyte interface, which severely degrade the cycling stability of AZIBs. Herein, an interfacial layer based on a quaternary ammonium functionalized polymer layer with iodide ions is proposed and applied to zinc anode surface to simultaneously mitigate dendrite growth and side reactions by optimizing Zn2+ transport and deposition behavior. The iodide ions serve as zincophilic sites that enhance the interfacial affinity toward Zn2+ and facilitate Zn2+ desolvation. The quaternary ammonium groups contribute to electrostatic regulation of interfacial ion distribution, thereby reducing anion participation near the Zn surface. This dual functional mechanism works synergistically homogenize Zn2+ flux and effectively mitigate dendrite growth. In addition, the uniform Zn2+ flux combined with improved surface hydrophilicity promotes the formation of a compatible and electrochemically stable interface on the zinc anode surface. Consequently, the QP@Zn||QP@Zn symmetric battery achieves a stable cycling lifespan over 2000 h at 5 mA cm–2/1 mAh cm–2, and maintains excellent rate performance at 15 mA cm–2. The QP@Zn||NVO full battery retains a specific capacity of 215 mAh g–1 after 1500 cycles at 5 A g–1. By integrating zincophilic iodide ions, quaternary ammonium groups, and a hydrophilic framework into the molecular design of the protective layer, this study not only provides feasible strategies for constructing high performance AZIBs, but also offers profound insights for regulating the zinc anode/electrolyte interface.
Ren et al. (Thu,) studied this question.