A Kinetic Study on the Aluminum Electrode in Molten 60 Mole Percent AlCl3-40 Mole Percent NaCl at 453K

[摘要] Steady-state anodic and cathodic polarization curves were developed for the Al electrode in 60 mole % AlCl3-40 mole % NaCl at 180¡É(453¢ªK). Ohmic resistance contributed substantially to the anodic polarization at current densities greater than 50 mA/cm2 even with capillary tip placed close to the electrode. This could not be rationalized from the resistivity of the melt, which would lead to a much smaller polarization. It was therefore concluded that a layer of high resistance AlCl3 (or AlCl3-rich melt) formed close to the anode surface. From the IR-corrected anodic Tafel and Allen-Hickling plots an apparent anodic charge-transfer coefficient of ¥áa = (2.3 RT/F)(d log i/d¥ç) = 1.5¡¾0.25 was obtained. At cathodic current densities greater than approximately 30 mA/cm2, slow ion diffusion and dendrite growth both interfered with the measurement of kinetic parameters.

[学科分类] 化学（综合）