Physical and electrochemical properties of acid 1-methyl-3-ethylimidazolium chloride/AlCl 3/LiAlCl 4 molten salt

Abstract

An acid molten salt was formed by means of mixing 1-methyl-3-ethylimidazolium chloride with AlCl 3 and LiAlCl 4 at ambient temperature. The solubility of LiAlC 4 in the acid molten salt was measured. Variations of specific conductivity, density and kinetic viscosity of molten salt with mole ratio of MeEtImCl/AlCl 3/LiAlCl 4, were observed. A solubility maximum of LiAlCl 4 with 54% in molar fraction was shown at a mole ratio of AlCl 3/MeEtImCl = 1.2. An increase in density and viscosity, and a decrease in specific conductivity were found with increasing the concentrations of LiAlCl 4 and AlCl 3. The dependence of specific conductivity of this acid molten salt upon temperature was found to display Vogel-Tammanm-Fucher behavior. However, Arrhenius behavior was observed at two special mole ratios of MeEtImCl/AlCI 3LiAlCl 4 = 1:1.5:0.05 and 1:1.5:0.10. The conductivity equations of this molten salt at various compositions were constructed. The ion interaction in the acid molten salt was studied using 7Li and 27Al nuclear magnetic resonance spectroscopic methods. The effect of concentrations of LiAlCl 4 and AlCl 3 on the ion interaction was also discussed.