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

SnO 2 nanolayer (∼10 nm) suppresses the dendritic growth of zinc and hydrogens gas evolution. • Ultra-thin SnO 2 layer (∼10 nm) is deposited on Zn metal via atomic layer deposition. • The SnO 2 passivation suppresses Zn dendrite growth. • The presence of SnO 2 layer leads to hydrogen gas suppression as desired. • The SnO 2 coated Zn shows striking improvements cycling stability and rate capability than the bare Zn in aqueous zinc ion battery. 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.