Controlling Epitaxial Zn Growth via Guided Laser Patterning toward High-Performance 6Ah Aqueous Zn||I₂ Batteries

Aqueous zinc-ion batteries (AZIBs) are attractive for grid-scale energy storage because of their safety, low cost, and environmental benignity. However, their practical use is limited by interfacial instability at the Zn anode, which induces nonuniform Zn²⁺ flux, dendritic growth, and parasitic H₂ evolution. Herein, we present a laser-induced surface patterning stategy that guides Zn epitaxial growth through a resistance-gradient-driven mechanism. Laser ablation forms periodic concave micro-holes, selectively removes the resistive carbonate-based surface layer from the exposed regions, and reconstructs the Zn texture from the (101) plane to the (002) basal plane. This surface-resistance contrast directs Zn²⁺ flux into the patterned holes, which serve as uniform nucleation sites and three-dimensional deposition reservoirs, enabling bottom-up Zn filling and compact homogeneous surface growth. Consequently, the patterned Zn||Zn symmetric cells achieve an exceptional lifespan of 972 cycles under high-rate conditions (10 mA cm^-2, 2 mAh cm^-2). Furthermore, a 6.5 Ah Zn||I₂ pouch cell operating at 2C (10 × 18 cm², areal capacity of 3.0 mAh cm^-2) and employing the laser-patterned Zn anode exhibits stable cycling for over 440 cycles, a Coulombic efficiency of 99.9%, and a capacity retention of 90.7%.