Anion Coordination Interactions in Solvates with the Lithium Salts LiDCTA and LiTDI

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• 作者：Dennis W. McOwen ; Samuel A. Delp ; Elie Paillard ; Cristelle Herriot ; Sang-Don Han ; Paul D. Boyle ; Roger D. Sommer ; Wesley A. Henderson
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 17, 2014
• 年：2014
• 卷：118
• 期：15
• 页码：7781-7787
• 全文大小：351K
• 年卷期：v.118,no.15(April 17, 2014)
• ISSN：1932-7455

文摘

Lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) and lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) are two salts proposed for lithium battery electrolyte applications, but little is known about the manner in which the DCTA^{鈥?/sup> and TDI鈥?/sup> anions coordinate Li+ cations. To explore this in depth, crystal structures are reported here for two solvates with LiDCTA鈥?G2)₁:LiDCTA and (G1)₁:LiDCTA鈥攚ith diglyme and monoglyme, respectively; and seven solvates with LiTDI鈥?G1)₂:LiTDI, (G2)₂:LiTDI, (G3)₁:LiTDI, (THF)₁:LiTDI, (EC)₁:LiTDI, (PC)₁:LiTDI, and (DMC)_1/2:LiTDI鈥攚ith monoglyme, diglyme, triglyme, tetrahydrofuran, ethylene carbonate, propylene carbonate, and dimethyl carbonate, respectively. These latter solvate structures are compared with the previously reported acetonitrile (AN)₂:LiTDI structure. The solvates indicate that the LiTDI salt is much less associated than the LiDCTA salt and that the ions in LiTDI, when aggregated in solvates, have a very similar TDI鈥?/sup>路路路Li+ cation mode of coordination through both the anion ring and cyano nitrogen atoms. Such coordination facilitates the formation of polymeric ion aggregates, instead of dimers. Insight into such ion speciation is instrumental for understanding the electrolyte properties of aprotic solvent mixtures with these salts.}