A vibrational spectroscopic study on the interaction between lithium salt and ethylene carbonate plasticizer for PAN-based electrolytes

The Raman and infrared (IR) spectra of ethylene carbonate (EC) containing various concentrations of lithium perchlorate have been studied. It was found that both the vibrational frequencies and the relative intensities of the bands related to the ring structure and C=O group of the EC molecule change with the concentration of LiClO4 in the solution. The results indicate that there are rather strong interactions between Li+ ions and EC molecules. The interactions between the Li+ ions and EC molecules occur on all three oxygen atoms of the carbonate group. Another result given by Raman and IR spectroscopy is that the vibrational modes of ClO4- anions at 460 and at 624 cm(-1) are nearly as sensitive as the previously reported ClO4- bands at 930 cm(-1) in detecting ion aggregates in the LiClO4/EC solutions.