Micro‐Terraced Surface Induced Directional Two‐Dimensional Diffusion Enables Dendrite‐Free Zinc Anodes

Aqueous zinc batteries have garnered significant attention owing to their low cost, high intrinsic safety, and environmental friendliness. However, their practical application is still hindered by poor cycling stability, primarily caused by uncontrolled Zn dendrite growth. Conventional strategies to suppress dendrites generally aim to convert undesired 2D diffusion, which favors dendrite formation, into 3D diffusion to promote uniform Zn deposition. In contrast, this study reports a dendrite-free Zn plating behavior achieved through directional 2D diffusion enabled by a micro-terraced surface, which is achieved by a Ti⁴⁺-etching strategy. Unlike conventional 2D diffusion, where Zn atoms aggregate and form dendrites, on the micro-terraced surface Zn atoms rapidly and orderly migrate along the terraces toward their intersection boundaries, resulting in uniform, dendrite-free plating. The micro-terraced Zn anodes deliver exceptional cycling stability over 6250 cycles at 5 mA cm^-2/1 mAh cm^-2. When paired with I₂ cathode, the full cells achieve above 83.4% capacity retention and average Coulombic efficiencies of 99.89% over 5000 cycles at 1.5 A g^-1. This work provides mechanistic insights into Zn deposition and offers a new design paradigm for developing high-stability energy storage systems.