Jing Penga,b, Lorenzo Carbonec, Mallory Gobeta, Jusef Hassound, Matthew Devanye, Steven Greenbauma
a Department of Physics & Astronomy, Hunter College of the City University of New York, New York, NY 10065, USA
b Doctoral Program in Chemistry, Graduate Center of the City University of New York, New York NY 10065, USA
c Chemistry Department, Sapienza University of Rome, P.zza A. Moro 5, 00185, Rome, Italy
d Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17, 44121, Ferrara, Italy
e Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, NY 10065, USA
NATURAL ABUNDANCE OXYGEN-17 NMR INVESTIGATION OF LITHIUM ION SOLVATION IN GLYME-BASED ELECTROLYTES
ABSTRACT: In this report, the lithium solvation behavior of two series of glyme-based electrolytes, with lithium trifluoromethanesulfonate (LiTf) or lithium-bis-(trifluormethanesulfonyl)-imide (LiTFSI) in six glymes with different chain length, is characterized using natural abundance oxygen-17 (17O) NMR spectroscopy. The effect of salt addition on chemical shift is observed by comparing the 17O NMR spectra of electrolytes and their corresponding neat solvents. The study reveals a more pronounced effect of the salt addition on the chemical shift of ether oxygens compared to terminal oxygens of glymes, thus suggesting a preferential coordination of Li+ with the ether oxygens. The 17O NMR data exhibit decreasing chemical shift changes with increasing chain length of glymes due to the increased number of ether oxygens coordinating each Li+ in the electrolytes. In addition, the trend of anion oxygen chemical shift, particularly for Tfanion, suggests an effect of the chain length on the ion association degree. The results illustrate the sensitivity of 17O NMR to subtle changes in the ion-solvent and ion–ion interactions.