<i>In situ</i> alloyed zinc–copper layer accelerates Zn ion migration for highly reversible Zn anodes

Abstract

Aqueous zinc-ion batteries (AZIBs) have garnered significant attention, but several obstacles associated with zinc anodes impede the advancement of AZIBs. Constructing protective coatings on Zn anodes is a promising strategy to curb zinc dendrite growth and side reactions, yet current techniques remain complex and inefficient. Herein, the in situ alloyed method is employed to generate a CuZn protective interface for a highly reversible Zn metal anode (60CuZn@Zn). Systematic characterization and theoretical calculations have elucidated that the protective layer is likely to effectively suppress the proliferation of zinc dendrites, accelerate the migration of zinc ions, and ameliorate interfacial side reactions. In addition, the optimized coating effectively modulates the interfacial electric field distribution, facilitates uniform nucleation of zinc crystals, and reduces the charge transfer resistance, thereby enhancing the electrochemical performance of the AZIBs. Consequently, the 60CuZn@Zn anode demonstrates an extended cycling life of over 2800 h at 1 mA cm−2/1 mAh cm−2 and maintains prolonged stability exceeding 1200 h even at a high current density of 10 mA cm−2/1 mAh cm−2. This work presents an accessible, cost-effective approach to fabricating protective coatings for engineering highly reversible zinc anode protective layers.