X-Ray absorption spectroscopy of LiBF₄ in propylene carbonate: a model lithium ion battery electrolyte

Abstract

Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li(+) ion in this model electrolyte. By generating linear combinations of the computed spectra of Li(+)-associating and free PC molecules and comparing to the experimental spectrum, we find a Li(+)-solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.

Solvent and Salt Effect on Lithium Ion Solvation and Contact Ion Pair Formation in Organic Carbonates: A Quantum Chemical Perspective

“…Although several experimental and theoretical works have focused on systems formed by pure EC, PC and DMC with the Li + ion [24][25][26][27][28][29][30][31] , solvation structure and dynamics of the cation in these solvents is still a subject of debate. More in details, Density Functional Theory (DFT) studies have shown that a (four-coordinated) tetrahedral geometry Li + (EC)4, is the dominant species [32][33][34] .…”

Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

“…We have recently used this combination of experimental and theoretical methodologies to study cation-cation pairing in aqueous solutions of guanidinium hydrochloride, 18 the hydrolysis of carbon dioxide in the carbon cycle, 19,20 and the solvation of Li + by propylene carbonate. 21 Here, we apply these techniques to the comparative study of ion solvation and pairing in aqueous solutions of NaNO 3 and NaNO 2 .…”

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

“…It is therefore ideal for probing liquid structure. Since introducing the use of liquid microjet technology in XAS of liquids in 2001, 45 we have employed this methodology to study a wide variety of phenomena in liquid systems, including ion solvation and pairing in water, 46,47 the solvation of lithium in propylene carbonate, 48 the hydrolysis of carbon dioxide, 49 and the structure of hydrated carbonic acid.…”