Low-temperature Electrodeposition of Aluminium from Lewis Acidic 1-Allyl-3-methylimidazolium Chloroaluminate Ionic Liquids

Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium. Systematic studies on deposition process have been performed by cyclic voltammetry and chronoamperometry. The surface morphology and X-ray diffraction (XRD) patterns of deposits prepared at different experimental conditions were also investigated. It was shown that the nucleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited. The crystallographic orientation of deposits was mainly influenced by temperature and current density. Smooth, dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA.cm(-2) and 313.2-353.2 K. Moreover, the current efficiency of deposition and purity of aluminium have been significantly improved, demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.