Preferential Stripping and Selective Passivation of Zinc Crystal Facets in Zinc-Metal Batteries

Developing stable zinc (Zn) anodes is crucial for the applications of aqueous Zn-metal batteries. However, the stripping process of the Zn anode, which governs subsequent plating, remains poorly understood. This initial reaction is critical to the Zn-metal battery performance. Here, we revealed the preferential stripping behavior of the Zn anode from a crystallographic perspective. The dissolution order of Zn crystal facets during the initial stripping, determined by their stripping energies, is found to be Zn(100) > Zn(101) > Zn(002). Among these, the Zn(100) facet dissolves first, leading to uneven Zn stripping. To mitigate this inhomogeneity, we propose a selective passivation strategy by introducing molecules that exhibit strong interactions with Zn(100) but weak interactions with Zn(002). This approach effectively slows the dissolution of Zn(100), promoting uniform and synchronous stripping across different crystal facets. As a result, the modified Zn anode shows enhanced cyclability, achieving a Coulombic efficiency of 99.9% in Zn||Cu asymmetric cells and a cycling life of 2500 h in Zn||Zn symmetric cells. Moreover, a Zn||I₂ pouch cell delivers a high capacity of ∼330 mAh and maintains stable performance for ∼1200 cycles. This work offers fundamental insights and a practical strategy for achieving homogeneous stripping in Zn-metal anodes.