Coherent Solid–Solution Interface With Near‐Zero Lattice Mismatch Enables Stable Zinc Anodes

ABSTRACT Aqueous Zn‐ion batteries (AZIBs) are attractive for large‐scale energy storage owing to their high theoretical capacity, intrinsic safety, and low cost. However, interfacial instability of Zn metal remains a major obstacle, leading to dendritic growth, parasitic reactions, and rapid capacity decay. Here, we introduce a coherent solid–solution interface (SSI) strategy with near‐zero lattice mismatch to stabilize the Zn metal anode. The in situ formed SSI exhibits a lattice mismatch of only 0.11% with Zn, enabling coherent Zn growth and suppressing detrimental side reactions. Combined experimental and theoretical analyses reveal that the SSI reduces interfacial polarization, suppresses HER, and promotes uniform lattice‐aligned dense Zn deposition. As a result, SSI‐Zn delivers stable Zn||Zn symmetric cell cycling for over 9100 h (1 year and 18 days) and achieves Zn||Cu asymmetric cell performance with a Coulombic efficiency (CE) of 99.9% over 10 000 cycles. In full cell configurations, Zn||AC cells and Zn||I 2 cells operate stably for over 120 000 cycles and 17 000 cycles, respectively, with average CE (ACE) values of 99.6% and 99.99%. Furthermore, an anode‐free Zn||Br pouch cell operates stably at an areal capacity of 5 mAh cm −2 with 99.4% ACE, achieving a practical energy density of 61 Wh kg −1 . By coupling near‐zero lattice mismatch with interfacial stabilization, this work demonstrates coherent interface engineering as a promising strategy toward high‐energy and long‐lifespan AZIBs.