Electrodeposition of Aluminum from 1,3-Dimethyl-2-Imidazolidinone/AlCl3 baths

This study investigated the use of novel organic solvent baths for the electrodeposition of aluminum at near-ambient temperatures. It was found that Al metal can be electrodeposited from baths that were composed of 1,3-dimethyl-2-imidazolidinone (DMI) and AlCl3, with an AlCl3 concentration greater than 50 mol%. IR spectroscopy indicated that Al2Cl7− ions were present in the baths that contained >50 mol% AlCl3, where the electrodeposition of Al occurs from Al2Cl7− ion. The DMI/AlCl3 baths with AlCl3 concentrations between 59 and 64 mol% retained a single liquid phase without precipitation at 25 °C, and therefore, they can be used for Al electrodeposition near room temperature. Smooth Al films could be obtained by galvanostatic electrodeposition at 40 °C using a DMI/AlCl3 bath with the addition of a trace amount of 1,10-phenanthroline.