Electrochemical assessment of highly reversible SnO₂–coated Zn metal anodes prepared via atomic layer deposition for aqueous Zn-ion batteries

Aqueous electrochemical energy storage systems that rely on earth-abundant elements are considered as cost-effective alternatives to current lithium-ion batteries which have dominated the technological landscape. For zinc-based energy storage, dendrite growth is an underlying challenge that needs to be addressed to enact high performance and long-term stability. In the present study, we employ atomic layer deposition to produce a thin tin oxide layer that allows dendrite-free cycling for aqueous zinc-ion batteries. Tin oxide is particularly interesting as it provides two distinct advantages—dendrite-free cycling and mitigation of parasitic hydrogen gas evolution. The presence of the tin oxide layer leads to hydrogen gas suppression and homogeneous zinc plating/stripping, both of which are essential to improve the performance of zinc-ion batteries. When paired in a full-cell configuration with manganese oxide, this anode delivers a high specific capacity of 273 mAh g⁻¹ at an imposed current rate of 100 mA g⁻¹. Through density functional theory calculations, we elucidate further that the adsorption energy of Zn for bare Zn is higher than that in the presence of a tin oxide layer.