Realizing Highly Stable Zinc Metal Anode by Constructing Recessed Structures with a Depth Gradient

Although aqueous zinc-ion batteries (AZIBs) and zinc-ion capacitors are highly promising for grid-scale energy storage, their zinc anodes are plagued by major issues such as dendritic growth, unwanted side reactions, and slow interfacial charge-transfer kinetics. Herein, a facile microimprinting strategy is employed to construct recessed structures with a depth gradient on zinc foil (DGRZn). This gradient architecture effectively guides preferential Zn 2+ deposition into the deep pit interiors by optimizing electrode wettability and electric field distribution, thereby confining zinc growth within the recessed structures and significantly suppressing dendrite formation and parasitic reactions. The electrochemical evaluations reveal that symmetric cells based on DGRZn achieve an extended cycling life of over 1300 h at 1 mA cm –2, along with excellent rate capability. The DGRZn anode exhibits a higher exchange current density, indicating significantly enhanced interfacial reaction kinetics. Notably, its apparent activation energy is moderately increased compared to that of flat zinc (FZn), which is attributed to the gradient structure inducing ordered ion deposition─a slightly elevated energy barrier that enables highly stable and reversible plating/stripping processes. Furthermore, in half-cells and zinc-ion capacitors, the DGRZn anode demonstrates high Coulombic efficiency, low voltage polarization, and superior long-term cycling stability. This work provides a promising pathway for designing high-performance metal anodes from the perspective of structure-guided deposition.