Guiding uniform Zn deposition with a multifunctional additive for highly utilized Zn anodes

Abstract

The practical applications of aqueous zinc-ion batteries (AZIBs) have been restricted by the fast growth of Zn dendrites and severe side reactions at the Zn/electrolyte interface. Herein, a multifunctional additive, L-leucine (Leu), is incorporated into a mild acidic electrolyte to stabilize the Zn anode. The Leu molecule, featuring both carboxyl and amino groups, exhibits strong interactions with Zn²⁺, which can reshape the solvation structure of Zn²⁺ and facilitate the uniform electrodeposition of Zn. Simultaneously, the Leu molecule exhibits preferential adsorption onto the Zn surface, effectively isolating it from direct contact with water, thus suppressing unwanted side reactions. Consequently, the Zn∥Cu asymmetric cell exhibits a high and stable coulombic efficiency of 99.5% at a current density of 5 mA cm⁻² for 1100 h. Importantly, the capacity retention of the Zn∥NH₄V₄O₁₀ full cell based on the Leu electrolyte reaches 80% after 1200 cycles at a current density of 2 A g⁻¹. The successful application of the low-cost Leu effectively enhances the cycling stability of the AZIBs and accelerates their applications.