Effect of Solvation Shell Structure and Composition on Ion Pair Formation: The Case Study of LiTDI in Organic Carbonates
Effect of Solvation Shell Structure and Composition on Ion Pair Formation: The Case Study of LiTDI in Organic Carbonates
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DOI：
10.1021/acs.jpcc.9b07469
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
Jeramie C. Rushing;Fedra M. Leonik;D. Kuroda
中科院分区：
文献类型：
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作者：
Jeramie C. Rushing;Fedra M. Leonik;D. Kuroda
有机碳酸酯是商业锂离子电池的组成部分，因为它们具有理想的性能，例如高介电常数。然而，有机碳酸酯的高粘度要求使用含有环状和直链碳酸酯的混合物。在二元混合物中，直链和环状有机碳酸酯竞争溶剂化锂盐。虽然优先溶剂化已被广泛研究，但混合溶剂化对锂离子的离子形态的影响是一个尚未详细研究的主题。在这项研究中，红外光谱和从头算化学计算被用来研究的溶剂化结构和动力学的变化作为溶剂组成的函数的模型系统：锂4，5-二氰基-2-（三氟甲基）咪唑（LiTDI）。TDI-腈谱带用于探测离子形态和分子环境的变化，因为腈是已知的电子的良好和灵敏的红外光谱报告物。
Organic carbonates are an integral part of commercial lithium-ion batteries due to their desirable properties, such as high dielectric constants. However, the high viscosity of organic carbonates requires the use of mixtures containing a cyclic and a linear carbonate. In binary mixtures, the linear and cyclic organic carbonates compete to solvate the lithium salt. While the preferential solvation has been extensively studied, the effect of the mixed solvation on the ionic speciation of the lithium ion is a topic that has not been studied in detail. In this study, infrared spectroscopies and ab initio chemical computations are utilized to study the change in the solvation structure and dynamics as a function of solvent composition for the model system: lithium 4,5-dicyano-2-(trifluoromethyl)imidazole (LiTDI). The TDI– nitrile bands are used to probe the changes in the ion speciation as well as in the molecular environment since nitriles are known to be good and sensitive IR spectroscopic reporters of the e...