Mechanistic study of Al electrodeposition from EMIC-AlCl3 and BMIC-AlCl3 electrolytes at low temperature

Aluminum was electrodeposited from two different ionic liquid electrolytes namely; 1-ethyl-3-methylimidazolicum chloride and AlCl3 (EMIC-AlCl3) and 1-butyl-3-methylimidazolium chloride (BMIC-AlCl3) at 90 ± 2 °C. Nodular morphology of aluminum was obtained at the copper substrate. To evaluate the reaction mechanism, chronoamperometric study was adopted. From the chronoamperometric analysis, it was observed that the reaction was controlled by instantaneous three-dimensional diffusion process. The diffusion coefficient (D) of Al2C7− was found to be 5.2-6.6 × 10−11 m2 s−1 and 2.2 × 10−11 m2 s−1 for EMIC-AlCl3 and BMIC-AlCl3 ionic liquid electrolytes, respectively. The nuclei density of electrodeposited aluminum on the copper was also confirmed by scanning electron microscope wherein uniformly distributed aluminum nodules were observed.