Temperature-Dependent Morphological Evolution of Sn Metal Anode for Aqueous Sn-Ion Batteries

There has been growing interest in aqueous batteries, which are considered safer and more cost-effective compared to Li-ion batteries. Among them, aqueous Sn-ion batteries have emerged as promising alternatives because of their high specific capacity and wide voltage window. Despite these numerous advantages, in aqueous-based electrolytes, significant variations in metal growth behavior with temperature lead to severe performance degradation, necessitating a fundamental investigation into the underlying mechanisms to develop high-performance aqueous batteries capable of operating across a wide temperature range. Therefore, this study for the first time examines the temperature-dependent Sn metal plating and stripping behavior in aqueous Sn-ion batteries. The results indicate that, at low temperatures, uneven pits are formed during stripping, leading to a rough and nonuniform surface. These pits serve as nucleation sites for deposition during plating, further exacerbating surface irregularities. In contrast, at high temperatures, stripping occurs uniformly along the grain boundaries and grain surfaces, resulting in a smooth and homogeneous surface. Similarly, plating under high-temperature conditions leads to uniform Sn deposition. In contrast, the corrosion tests reveal that pits form on the electrode surface under high-temperature conditions, leading to deterioration. These findings are expected to contribute to the development of high-performance aqueous Sn-ion batteries.