3D Hierarchical Copper Substrates With Homogenous Anode‐Electrolyte Interphase for Highly Reversible Aqueous Zinc Batteries

Achieving highly reversible Zn plating/stripping is essential for developing high‐energy‐density aqueous zinc‐metal batteries (AZMBs). However, challenges exist in undesirable coulombic efficiency (CE) due to inevitable water‐related parasitic side‐reactions and dendrite growth, arising from uneven anode interface. To address these issues, we construct a 3D hierarchical anode interphase by manufacturing homogeneous Zn nucleation sites (via plasma pretreatment) and followed by grafting hydrophobic protecting layer (via spin‐coating zinc stearate) onto copper substrates (Zn(St) 2 @P‐Cu). This design combines water‐resistant organic chains that suppress hydrogen evolution, ensuring interfacial stability. Meanwhile, the synergistic effect between ion‐conductive Zn(St) 2 transfer overlayer and electron‐regulated plasma‐treated underlayer promotes effective Zn nucleation and uniform preferential (002) plane deposition. Consequently, Zn||Cu half cells enable ultrahigh CE (ca. 99.6%) and prolonged cycling stability (1000 cycles at 5 mA cm −2 ). Building up this, a Zn(St) 2 @P‐Cu||Zn x NaV 3 O 8 ·1.5H 2 O anode‐free full cell delivers a high energy density of 89.8 Wh kg −1 (based on the active material) and stable operation over 200 cycles. This work offers a universal strategy to promote the development of high‐energy‐density Zn‐based batteries, looking toward for practical energy storage applications.