Competitive Cationic Adsorption‐Driven Dynamic Electrostatic Shielding Enables Ultra‐Stable Zn Metal Anodes

The non‐uniform deposition of zinc anodes restricts the practical application of aqueous zinc metal batteries. Constructing a stable zinc anode/electrolyte interface to inhibit dendrite formation is a key step to improve the cyclic stability of aqueous zinc metal batteries. Here, we propose dynamic electrostatic shielding driven by competitive cation adsorption to achieve ultra‐stable zinc anodes, and reveal the mechanism of rearranging the inner Helmholtz layer to optimize zinc dense deposition. The R ⁺ preferentially competes for adsorption to occupy the inner Helmholtz layer and weakens zinc rejection through electrostatic shielding, which accelerates the migration kinetics of zinc during electroplating. In addition, the electric field at the zinc/electrolyte interface is modulated, improving the deposition pattern of Zn ²⁺ and guiding its dense deposition. In particular, K ⁺ has the best comprehensive modulation effect, achieving a symmetrical battery life of over 3200 h in 5 mA cm ⁻² , and stripping/plating on copper foils for over 5000 cycles with an average coulombic efficiency of 99.86%. This work contributes to a deeper understanding of the mechanism by which electrolyte cations affect the electrode‐electrolyte interface, opening up a unique pathway to achieve stable, reversible zinc‐ion batteries.