Achieving Uniform Zinc Deposition by Electron‐Rich Adsorption Trace Acid Molecule Additive for Ultra‐High‐Rate Zinc‐Ion Batteries

Abstract

The instability of zinc (Zn) anodes in aqueous electrolytes presents a major obstacle to the widespread commercial use of Zn-ion batteries owing to irreversible reactions and sluggish desolvation kinetics of the electrolyte. This study introduces a novel additive to improve Zn anodes using acetohydroxamic acid (AHA) in a conventional ZnSO₄ (ZSO) electrolyte system to optimize the Zn²⁺ diffusion behavior and desolvation kinetics, thus promoting uniform Zn deposition on the metallic Zn surface. Both experimental and theoretical calculations demonstrate that AHA molecules tend to replace H₂O molecules and attach to the Zn anode, thereby mitigating side reactions and dendrite formation. Consequently, the Zn||Zn symmetric cells with the AHA additive achieve a stable cycle life of 2995 h at 1 mA cm^-2 and endured extremely high current densities of 8 mA cm^-2 for over 1000 h. The Cu||Zn asymmetric cells stabilized over 2100 cycles with an average Coulombic efficiency of 99.3%. The full cell configuration using the NH₄V₄O₁₀||Zn system exhibits an improved performance, with a capacity retention of 81.9% after 700 cycles at a current density of 5 A g^-1. This study underscores the importance of AHA additives in regulating Zn anodes to enhance the lifespan of Zn-ion batteries.