Molten salt electrolytes. I. Experimental and theoretical studies of LiI/AlCl3

Molten LiI/AlCl3 with different molar ratios of LiI to AlCl3 were prepared and characterized by Raman spectroscopy, thermal analysis, and impedance me asurements. The LiI/AlCl3 adducts melt at 70-80 degreesC and the Raman spec trum indicates that a variety of haloaluminates exist in the system. The 1: 1 adduct has the highest ionic conductivity, 2x10(-6) S/cm at 25 degreesC, and the conductivity increases dramatically as the temperature is increased . Molecular dynamics (MD) simulations suggest that several haloaluminates a re present in the adducts. Ab initio calculations were carried out on the s pecies that were predicted by MD simulations and these results were compare d with Raman spectra, and good agreement was obtained. Several-ns-long MD s imulations allowed us to study the conductivity and relaxation processes in the 1:1 and 1:2 melts at higher temperatures. (C) 2001 American Institute of Physics.