X‐ray total scattering measurements are carried out for the typical electrolyte used in lithium‐ion batteries, that is, the mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) electrolyte with LiPF₆ salt. The obtained pair distribution function is compared with that of the EC/EMC solvent without LiPF₆, to investigate the effect of the Li⁺ cation on the intramolecular structure. It is found that the peak shift corresponding to the shrinking of the CO bonds is induced by dissolving LiPF₆. Also, the peak height becomes lower by the addition of LiPF₆. These behaviors are also observed by the X‐ray total scattering measurements for the mixture of EC and dimethyl carbonate (DMC) with and without LiPF₆. Also, it is ascertained that such a shrinking is present in EC/DMC electrolytes by means of neutron total scattering. First‐principles calculations on the basis of the density functional theory for isolated EC, EMC, and DMC molecules with the Li⁺ cation confirm that the shrinking of the CO bond is accompanied by the formation of the solvation structure. The observed structural variations induced by adding LiPF₆ will be a good indicator for the formation of the solvation structure.

中文翻译：

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通过X射线全散射研究的锂盐引起的碳酸盐电解质的结构变化。

对于锂离子电池中使用的典型电解质，即碳酸亚乙酯（EC）和碳酸乙基甲基酯（EMC）电解质与LiPF ₆盐的混合物，进行X射线总散射测量。将获得的对分布函数与不含LiPF ₆的EC / EMC溶剂的对分布函数进行比较，以研究Li ⁺阳离子对分子内结构的影响。发现通过溶解LiPF ₆引起与CO键的收缩相对应的峰移动。另外，通过添加LiPF ₆，峰高变低。通过使用ECPF和不使用LiPF ₆的EC和碳酸二甲酯（DMC）的混合物的X射线总散射测量也可以观察到这些行为。同样，通过中子全散射可以确定在EC / DMC电解质中存在这种收缩。根据对具有Li ⁺阳离子的孤立EC，EMC和DMC分子的密度泛函理论的第一性原理计算，证实CO键的收缩伴随着溶剂化结构的形成。通过添加LiPF ₆引起的观察到的结构变化将是形成溶剂化结构的良好指示。