Mapping Zinc Electrodeposition in Different Aqueous Electrolytes: Reduction Behaviors and Morphology Evolution

ABSTRACT

Controlling aqueous zinc (Zn) electrodeposition is challenging because electrolyte‐dependent Zn coordination, interfacial side reactions, nucleation kinetics, and mass transport generate competing morphological transitions. Herein, we investigate the electrolyte‐dependent Zn deposition behavior and morphological evolution via electrochemical analyses and operando microscopy. We identify a fundamental trade‐off that ZnSO ₄ electrolytes promote Zn plates but suffer from high energy consumption (∼2.64 kWh kg ⁻¹ ), whereas alkaline KOH‐ZnO electrolytes exhibit lower energy consumption (∼1.71 kWh kg ⁻¹ ) but naturally form mossy or dendritic powders. We regulate current density and introduce an additive to control Zn deposition, thereby enabling either Zn powders or Zn plates in KOH‐ZnO electrolytes. We achieved the synthesis of mossy, plate‐like, and dendritic Zn in a laboratory electrolyzer with a 32 cm ² cathode via current modulation. Both the ZnSO ₄ and KOH‐ZnO electrolytes exhibited average Coulombic efficiencies above 99.0% over 200 cycles at optimized current densities. This work provides both fundamental and engineering insights for tailoring Zn morphologies for next‐generation energy storage and customized Zn materials production.