Organic Acid Etching Strategy for Dendrite Suppression in Aqueous Zinc‐Ion Batteries

Abstract Aqueous zinc ion batteries (AZIBs) represent a promising technology for grid‐scale energy storage due to their innate safety, low cost, and environmental friendliness. However, planar Zn foil intrinsically suffers from limited ion and electron transport pathways, poor wettability, and surface passivation, preventing the homogenous deposition of metallic Zn and poor durability of AZIBs. Herein, a 3D Zn foil with hierarchical porous architecture is developed through a facile non‐aqueous organic acid etching strategy. The 3D Zn anode is pore‐rich and cavity‐rich, leading to significantly enhanced accessibility to aqueous electrolytes. Accordingly, this 3D Zn anode enables preferential plating of Zn in the porous texture with suppressed dendrite growth, as confirmed by ex situ scanning electron microscopy and finite element analysis. The cycle life of the 3D Zn anode is sustained over 930 and 1500 h at 4.0 mA cm −2 ‐2.0 mAh cm −2 and 1.0 mA cm −2 ‐1.0 mAh cm −2 , respectively. Furthermore, the assembled 3D Zn and α‐MnO 2 full batteries demonstrate a prolonged cycle life of 3000 cycles with improved rate performance. The etching strategy using non‐aqueous organic acid paves a new way to fabricate 3D metal anodes for Zn and other metal anode batteries.