Aluminum electrodeposition from mixtures of AlCl3/LiCl/DMSO2 [dimethylsulfone (CH3)2SO2] has been studied employing the techniques of chronopotentiometry, voltammetry, and chronoamperometry. The diffusion coefficient of the reducible Al(III) species Al[(CH3)2SO2]3+ was determined by each of the three electrochemical techniques and found to be in reasonable agreement with each other. Analysis of chronoamperograms indicate that the deposition process involves progressive nucleation with diffusion-controlled growth of the nuclei. Calculated nuclear site densities and average nuclei sizes are in agreement with scanning electron microscopy images.