Vibrational Spectroscopic Study on Ion Solvation and Association of Lithium Perchlorate in 4‐Methoxymethyl‐ethylene Carbonate

Abstract

Solvation interaction and ion association in solutions of lithium perchlorate/4-methoxymethyl-ethylene carbonate (MEC) have been studied by using Infrared and Raman spectra as a function of concentration of lithium perchlorate. The splitting of ring deformation band and ring ether asymmetric stretching band, and the change of carbonyl stretching band suggest that there should be a strong interaction between Li + and the solvent molecules, and the site of solvation should be the oxygen atom of carbonyl group. The apparent solvation number of Li ＋ was calculated by using band fitting technique. The solvation number was decreased from 3.3 to 1.1 with increasing the concentration of LiClO 4 /MEC solutions. On the other hand, the band fitting for the 4 ClO -band revealed the presence of contact ion pair, and free 4 ClO -anion in the concentrated solutions.

Vibrational Spectroscopic Study on Ion Solvation and Ion Association of Lithium Tetrafluoroborate in 4‐Ethoxymethyl‐ethylene Carbonate

“…In our previous investigation, 7 we have reported the results of IR and Raman spectroscopic study on the ion solvation and association of lithium perchlorate in 4-methoxymethyl-ethylene carbonate (MEC), a new molecular solvent synthesized in our laboratory in order to optimize the skeletal ring structure of EC and PC. As an extension of our series of studies and in order to develop a new kind of lithium ion battery electrolyte, we designed and synthesized another molecular solvent, 4-ethoxymethyl-ethylene carbonate (EEC).…”

Solvate Structures and Computational/Spectroscopic Characterization of LiClO4 Electrolytes

“…The highest intensity ClO 4 – anion Raman ν 1 band, near 963 cm –1 in the LiClO 4 salt (Figure ) and near 933 cm –1 for the uncoordinated anion, is due to the Cl–O symmetric stretching vibration . This band is highly sensitive (i.e., band positional shift) to Li + cation coordination and many studies have examined this band to identify solvates in solution via the assignment of the band positions to the uncoordinated ClO 4 – anion and the anion coordinated to one or more Li + cations. − Unfortunately, as noted above, the Raman ν 2 , ν 3 and ν 4 bands due to symmetric stretching, antisymmetric stretching and antisymmetric deformation vibrations, respectively, do not permit the facile assignment of the Li + cation coordination modes since several bands are associated with these vibrations and the band positions tend to overlap with the bands for solvent molecules (see Supporting Information). In addition, chlorine isotopes have a natural abundance of 75.8% 35 Cl and 24.2% 37 Cl. , Two bands thus occur for each of the ClO 4 – vibrational modes in which the chlorine nucleus in displaced (i.e., the ν 3 and ν 4 bands) .…”