Electrochemical properties of graphite negative electrodes in organic electrolyte solutions containing multivalent cation

研究了碳酸丙烯酯（PC）溶液中锂离子的结构与锂离子嵌入石墨的关系。为了控制溶剂化锂离子的结构，加入了比锂离子更强的刘易斯酸。使用多价阳离子如钙离子和镁离子。加入一定量的钙离子，使锂离子在Ca/Li = 1.1时嵌入石墨层。用二甲基亚砜代替PC对溶剂化阳离子的结构进行了拉曼分析。在DMSO基溶液中，发现钙的加入减少了游离DMSO，并表明锂离子的溶剂化数减少。最后，加入碳酸二甲酯作为粘度稀释剂。结果表明，控制溶剂化锂离子的结构对锂离子电池的进一步发展具有重要意义。

In this study, the relationships between the structure of solvated-lithium ion and the intercalation of lithium ion into graphite in propylene carbonate (PC) solution was investigated. In order to control the structure of solvated-lithium ion, stronger Lewis acid than lithium ion was added. Multivalent cations such as calcium ion and magnesium ion were used. Addition of a certain amount of calcium ion enabled lithium ion to intercalate into graphite at the ratio of Ca/Li = 1.1. Instead of PC, dimethyl sulfoxide (DMSO) was used for the Raman analysis of the structure of solvated cation. In the DMSO-based solution, it was found that the addition of calcium decreased the free-DMSO and suggested the decrease of solvation number of lithium ion. Finally, dimethyl carbonated was added as the diluent of viscosity. The results indicated that the control of the structure of solvated-lithium ion is quite important for the further development of lithium ion batteries.