Electrodeposition of aluminium from 1-butyl-1-methylpyrrolidinium chloride/AlCl3 and mixtures with 1-ethyl-3-methylimidazolium chloride/AlCl3

In this paper we show that nanocrystalline aluminium can be electrodeposited from the ionic liquid 1-butyl-1-methylpyrrolidinium chloride ([Py1,4]Cl/AlCl3) (40/60 mol%). The study comprises electrochemical experiments such as cyclic voltammetry, constant potential electrolysis, SEM and XRD measurements. Thick and uniform layers of aluminium are obtained from [Py1,4]Cl/AlCl3 with an average crystal size of 20 nm at 100 °C. Aluminium deposits obtained from 90:10 vol% and 80:20 vol% of [Py1,4]Cl/AlCl3 and [EMIm]Cl/AlCl3 are nanocrystalline at 100 °C. The presence of imidazolium cations seems to alter the electrode/electrolyte interface to some extent as nanocrystalline and microcrystalline aluminium deposits are obtained from the ionic liquid mixtures at compositions of 70:30 vol% of [Py1,4]Cl/AlCl3 and [EMIm]Cl/AlCl3 and below.