Interfacial Electric Field Regulation via Weakly Solvated Cation Additives for Dendrite-Free Zinc Anodes

Aqueous zinc-ion batteries (AZIBs) have garnered considerable attention in recent years owing to their high energy density, cost-effectiveness, and inherent safety. However, the persistent challenge of dendrite formation continues to impede their practical implementation. By leveraging the high desolvation tendency of Cs⁺, we introduced Cs⁺ as a shielding ion to generate a shielding effect, which mitigates the adverse impacts of zinc tip-induced uneven deposition and effectively suppresses dendrite formation. The electrostatic adsorption of Cs⁺ at the electrode-electrolyte interface increases the interfacial capacitance by fivefold. Furthermore, Cs⁺ significantly inhibits parasitic reactions such as hydrogen evolution, thereby enhancing the reversibility of zinc deposition. Notably, we observed that Cs⁺ reduces polarization during battery cycling, enabling zinc-copper half-cells to maintain stable Coulombic efficiency over 2500 charge/discharge cycles. This study is expected to provide critical insights into advancing zinc-ion battery technology and accelerating its practical applications.