Digging into Electrolyte Interactions—Challenging the Conventional Wisdom
This talk will discuss the utility (or lack thereof) of solvent polarization parameters (e.g., dielectric constant (ε), Gutmann donor number (DN), etc.) for determining the strength of solvation interactions with Li+ cations, the challenges associated with using Raman spectroscopy to obtain accurate Li+cation solvation numbers and determine the solvate species present in solution, how the strength of the ionic association interactions is uncorrelated with salt solubility and how Walden plots are poorly suited for characterizing the ionic association characteristics of electrolytes. The invaluable information which may be gleaned from the fusion of experimental and computational (Fig. 1) methods will be emphasized to provide a rigorous discourse on both the phase behavior and properties of dilute electrolytes, as well as highly concentrated (> 5M ) electrolytes.
Figure 1. Snapshot of a MD simulation of a (AN)n-LiBF4mixture (n = 10 or 1.7M): (top) original MD simulation box and (bottom) same MD simulation box with the uncoordinated acetonitrile (AN) molecules colored gray and the solvates grown across the periodic boundaries (Li-purple, B-tan, F-light green).
The authors wish to express their gratitude to the U.S. Department of Energy (DOE) Office of Basic Energy Science-Division of Materials Sciences and Engineering and the Vehicle Technologies Program which supported the experimental research under awards DE-SC0002169 and DE-AC02-05-CH11231.