Zn dendrite suppression and solid electrolyte interface control using N-allylthiourea as an electrolyte additive for aqueous Zn-ion batteries

Despite being promising candidates for Li-ion batteries, the development of aqueous Zn-ion batteries is still impeded by inherent unresolved problems such as dendrite growth and side reactions on the anode side. In this study, a stabilized Zn-electrolyte interface is established using N-allylthiourea (ATU) as an additive in mildly acidic electrolytes because of its strong affinity towards Zn2+ ions and the Zn metal. Through this favorable electrostatic adsorption, side reactions owing to water molecules are inhibited, and uniform Zn deposition is achieved, leading to highly reversible stripping/plating performance. Consequently, a stable cycling performance of up to 500 h at a current density of 1 mA cm–2 and an areal capacity of 1 mAh cm–2 is demonstrated for Zn symmetric cells. Furthermore, a Zn|VO2 full cell validates the possible practical use of ATU where it delivers a promising cycling performance of up to 300 cycles at a current rate of 1C (200 mA g–1). This study contributes insights into the role of additives in optimizing battery performance and creates opportunities for further exploration of similar compounds in pursuit of sustainable energy storage systems.