Aluminum Electrodeposition in Dry Air Atmosphere: Comparative Study of an Acetamide–AlCl3 Deep Eutectic Solvent and a 1-Ethyl-3-Methylimidazolium Chloride–AlCl3 Ionic Liquid

Abstract

Aluminum electrodeposition using ionic liquids or deep eutectic solvents has attracted significant interest for coating applications. Although Al electrodeposition is usually carried out in a nitrogen- or argon-filled glove box, there may be a potential for process cost reduction if the Al electrodeposition process could be carried out in a dry atmosphere. In this study, we examined two commonly used baths, namely a 1-ethyl-3-methylimidazolium chloride (EMImCl)–AlCl3 ionic liquid and an acetamide (AcAm)–AlCl3 deep eutectic solvent, to determine their respective feasibilities for the electrodeposition of a uniform Al film in dry air. Electrodeposition in dry air using the AcAm–AlCl3 bath produced uniform Al films even after the bath had been used for more than 10 weeks, whereas electrodeposition in dry air using the EMImCl–AlCl3 bath failed to produce an Al film covering the entire substrate. The current efficiency was almost 100% in the AcAm–AlCl3 bath, whereas the value decreased to 50% in EMImCl–AlCl3 bath in dry air. The findings of this study therefore reveal that AcAm–AlCl3 is a suitable bath for Al electrodeposition in dry air.