Electrodeposition of Aluminum from Ionic Liquids

Abstract

Electrodeposition of aluminum was studied in three hydrophobic ionic liquids, trimethylhexylammonium bis(trifluoromethylsulfonyl)imide (TMHA-TFSI), trimethylpropylammonium bis(trifluoromethyl -sulfonyl)imide (TMPA-TFSI), 1-n-butyl-N-methylpyrrolidinium bis (trifluoromethylsulfonyl)imide (BMP-TFSI). Bright deposits were obtained only in the BMP-TFSI melt containing AlCl3 with low current densities, while gray deposits were obtained from the TMPA-TFSI melt. In the BMP-TFSI melts, the deposits became black and less adhesive with an increase in current density. The current efficiency for the aluminum deposition was quite high in the BMP-TFSI melt, and the thick deposits such as 20μm could be obtained. The effects of the aluminum chloride concentration were also examined.