Crystallographic Reorientation Induced by Gradient Solid-Electrolyte Interphase for Highly Stable Zinc Anode

Oriented zinc (Zn) electrodeposition is critical for the long-term performance of aqueous Zn metal batteries. However, the intricate interfacial reactions between the Zn anode and electrolytes hinder a comprehensive understanding of Zn metal deposition. Here, the reaction pathways of Zn deposition and report the preferential formation of Zn single-crystalline nuclei followed by dense Zn(002) deposition is elucidated, which is induced by a gradient solid-electrolyte interphase (SEI). The gradient SEI composed of abundant B-O and C species facilitates faster Zn²⁺ nucleation rate and smaller nucleus size, promoting the formation of Zn single-crystalline nuclei. Additionally, the homogeneity and mechanical stability of SEI ensure the crystallographic reorientation of Zn anodes from Zn(101) to (002) planes, efficiently inhibiting dendrite growth and metal corrosion during the Zn²⁺ stripping/plating process. These advantages significantly enhance the stability of the Zn anode, as demonstrated by the prolonged cycling lifespan of symmetric Zn batteries and exceptional reversibility (>99.5%) over 5000 cycles in Zn//Cu asymmetric batteries. Notably, this strategy also enables the stable operation of anode-free Zn//I₂ batteries with a long lifespan of 3000 cycles. This work advances the understanding of Zn electrochemical behaviors, encompassing Zn nucleation, growth, and Zn²⁺ stripping/plating.