Spirally Grown Zinc‐Cobalt Alloy Layer Enables Highly Reversible Zinc Metal Anodes

Abstract Although Zn‐ion batteries have gained extensive attention, it persistently suffers from uncontrolled dendrite growth and severe side reactions on zinc (Zn) anodes. Here, a spirally grown 3D ZnCo overlayer is designed on one side of commercial zinc foil by means of constant‐current electrodeposition to address these challenges. In contrast to Zn crystal planes, the ZnCo crystal planes mainly exposed to the side of the 3D spiral structure exhibit superior zincophilicity, promoting the bottom‐up layer‐by‐layer Zn growth. During plating, the surface of Zn metal with ZnCo overlayer (ZnCo) gradually becomes flat by constraining the diffusion behavior of Zn 2+ ions. The resulting ZnCo–ZnCo cells demonstrate stable operation for over 620 h at a large current density of 5 mA cm −2 . Furthermore, the ZnCo‐NH 4 V 4 O 10 pouch cell delivers an initial capacity of 190 mA h g −1 and maintains a high capacity retention of 81% after 400 cycles. This alloying strategy of electro‐deposition offers new insights into the design of highly reversible Zn anodes.