Solvate Structures and Computational/Spectroscopic Characterization of LiClO4 Electrolytes

A Raman spectral evaluation of numerous crystalline solvates with lithium perchlorate (LiClO4) has been conducted over a wide temperature range. Two new solvate crystal structures─(PMDETA)1:LiClO4 and (THF)1:LiClO4 with N,N,N′,N″,N″-pentamethyldiethylenetriamine and tetrahydrofuran─have been determined to aid in this study. With a help of density functional theory (DFT) and molecular dynamics (MD) simulations, the spectroscopic data have been correlated with varying modes of ClO4–···Li+ cation coordination within the solvate structures to create a characterization tool to facilitate the Raman band assignments for the determination of ionic association interactions within solid and liquid electrolytes containing LiClO4. This study demonstrates that many of the spectroscopic evaluation conclusions reported in the scientific literature for LiClO4-based electrolytes are inaccurate.