Interfacial electrochemistry of Zn anodes in aqueous electrolytes with combined organic cation and halide additives

Abstract

Aqueous zinc-ion batteries (AZIBs) have attracted considerable interest as energy storage systems for large-scale applications owing to their low cost, high safety, elemental abundance, and environmental compatibility. However, the Zn metal anode in AZIBs continues to face challenges such as dendrite growth and parasitic side reactions, including hydrogen evolution, corrosion, and byproduct formation. Extensive studies have demonstrated that the electrochemical behavior of Zn anodes during repeated plating and stripping is highly sensitive to electrolyte composition, resulting in pronounced variations in Zn deposition morphology, reversibility, and interfacial stability. Accordingly, electrolyte additives have been widely explored as an effective approach to modulate Zn anode behavior. In this work, we compare the electrochemical responses of Zn anodes in aqueous electrolytes containing quaternary ammonium iodide additives, using tetrabutylammonium iodide (TBAI) as a representative example, over a low concentration range. Particular attention is given to changes in interfacial electrochemical characteristics observed under typical AZIB testing conditions.