Highly Reversible Dendrite-Free Zinc Anode Enabled by a Bilayered Inorganic-Metal Interface Layer

The unavoidable dendrite growth and side reactions are two major issues that lead to unsatisfactory cycling stability of the Zn metal anode and premature battery failure, which constrains the wide practical application of aqueous Zn-ion batteries. Herein, a bilayered zinc fluoride-indium interface-modified zinc anode (ZnF₂-In@Zn) is in situ-constructed to solve these two issues through a simple solution-dipping strategy. The outer ZnF₂ layer assures sufficient desolvation of hydrated Zn²⁺ and even Zn²⁺ flux; meanwhile, the interior In layer further contributes to the uniform distribution of the electric field and lower energy barrier of Zn²⁺ nucleation, achieving dendrite-free and side reaction-free Zn deposition. With synergistic regulation from the bilayered composite interface, the ZnF₂-In@Zn anode exhibits outstanding cycling stability (over 4200 h at 1 mA cm^-2), achieving a cumulative capacity of over 5250 mAh cm^-2 even under a high current density of 5 mA cm^-2. This work proposes an advanced understanding of reasonable interface engineering for tackling multiple challenges faced by metal anodes.