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

作者：McOwen Dennis W; Delp Samuel A; Paillard Elie; Herriot Cristelle; Han Sang Don; Boyle Paul D; Sommer Roger D; Henderson Wesley A^*

来源：Journal of Physical Chemistry C, 2014, 118(15): 7781-7787.

DOI：10.1021/jp412601x

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(-) and TDI- anions coordinate Li+ cations. To explore this in depth, crystal structures are reported here for two solvates with LiDCTA-(G2)(1):LiDCTA and (G1)(1):LiDCTA-with diglyme and monoglyme, respectively; and seven solvates with LiTD1-(G1)2:LiTDI, (G2)2:LiTDI, (G3)1 :LiTDI, (THF)1:LiTDI, (EC),:LiTDI, (PC)(1):LiTDI, and (DMC)(1/2):LiTD1-with monoglyme, diglyrne, 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-center dot center dot center dot 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.

• 出版日期2014-4-17