Dynamic Zn ²⁺ ‐Conductive Protective Layer for Durable Zinc Anode in Aqueous Zinc‐Ion Batteries

Abstract

ABSTRACT The Zn anode in aqueous zinc‐ion batteries (AZIBs) suffers from hydrogen evolution reaction (HER), by‐product accumulation, and dendrite growth, severely restricting practical viability. To address these challenges concurrently, we propose a dynamic Zn 2+ ‐conductive protective layer strategy, which involves constructing an in situ ZnOHF layer on the Zn anode and incorporating F − into the electrolyte. Zn 2+ ‐conductivity and reducibility of ZnOHF layer guide uniform Zn nucleation and deposition, thereby inhibiting dendrite formation. Crucially, the addition of F − to the electrolyte enables the dynamic regeneration of the ZnOHF layer during cycling and the conversion of detrimental by‐products into favorable ZnOHF. Additionally, HER is effectively suppressed by isolating the Zn anode from the aqueous electrolyte via ZnOHF interfacial layer, and decreasing water activity through F − ‐induced elevation of electrolyte pH from 4.1 to 5. As a result, the protected Zn anode enables the symmetrical cell to operate stably for 3100 h at 0.5 mA cm −2 , and a full cell to retain 85% capacity after 4000 cycles at 10 A g −1 . Moreover, a 90 cm 2 pouch cell delivers an initial capacity of 240 mAh and maintains 70% capacity after 200 cycles, highlighting its practical viability. This work presents an effective and scalable interface engineering approach to realize durable Zn anodes for practical AZIBs.