Interfacial Fluorinated Ion Crowding Enables Reversible Zinc Metal Batteries

ABSTRACT Aqueous zinc metal batteries (AZMBs) are promising candidates for large‐scale energy storage owing to their intrinsic safety. However, their lifespan is severely limited by side reactions such as dendrite growth and hydrogen evolution at the Zn‐electrolyte interface. Conventional single‐electrolyte‐additive approaches are thermodynamically constrained, yielding only insufficient coverage of the inner‐Helmholtz plane (IHP) and poor control of interfacial reactions. Here, we report an interfacial fluorinated‐ion crowding strategy by simultaneously introducing multiple low‐concentration fluorinated additives. Computational and spectroscopic analyses reveal that various‐sized F‐groups densely occupy the IHP, displacing water molecules and homogenizing Zn 2+ flux. This emergent crowding effect, inaccessible to single‐additive strategies, enables unprecedented interfacial regulation. Electrochemical tests demonstrate ultrastable Zn plating/stripping over 1200 h at 5 mA cm −2 and 1800 h at 10 mA cm −2 , more than tenfold longer than the baseline electrolyte. This work establishes interfacial ion crowding as a powerful design principle, rooted in fundamental electrochemistry, offering a pathway toward high‐performance and durable AZMBs.