EC、PC溶剂在石墨表面反应的第一性原理研究  

First-principles study on the reaction of EC and PC solvent on graphite

作　　者：丁爽 刘恋 周江 DING Shuang;LIU Lian;ZHOU Jiang(CETC Lantian Technology Co.,Ltd.,Tianjin 300384,China)

机构地区：[1]中电科蓝天科技股份有限公司,天津300384

出　　处：《电源技术》2024年第5期857-861,共5页Chinese Journal of Power Sources

摘　　要：基于第一性原理利用密度泛函理论对溶剂EC、PC和EMC的电子性质及其与石墨负极的反应进行了理论计算。相较于EC和EMC溶剂,PC具有更小的带隙,最容易发生电子跃迁进而发生氧化还原反应。EC和EMC溶剂分子嵌入石墨层中仅仅扩大了石墨的层间距,而PC嵌入后与石墨发生了反应,破坏了石墨结构。随着充电程度的增加,PC与石墨的反应能减小,石墨结构更容易被破坏。比较了锂离子和钠离子的溶剂化能和嵌入石墨的反应能。计算结果显示:电解液中的杂质钠离子具有更小的去溶剂化能,在石墨负极表面与锂离子发生竞争,优先嵌入到石墨中,阻碍锂离子嵌入。With the first principles and density functional theory,the electronic properties of ethylene carbonate(EC),propylene carbonate(PC)and ethyl methyl carbonate(EMC)as solvent and their reactions with graphite anode were calculated.Compared with EC and EMC,PC is most prone to electronic transition and oxidation-reduction reaction proceed owing to the smaller band gap.The embedding of EC and EMC solvent molecules in the graphite layer only enlarged the graphite layer spacing,while PC reacted with the graphite after embedding to destroy the structure.With the increase of the degree of charging,the reaction energy between PC and graphite can be reduced,and the graphite structure is easier to be destroyed.The solvation energy and the reaction energy of embedded graphite for lithium ion and sodium ion were investigated.The impurity sodium ion in the electrolyte has a smaller desolvation energy and competes with lithium ion on the graphite negative surface,which prefers to embed into graphite and hind the embedding of lithium ion.

关 键 词：碳酸乙烯酯 碳酸丙烯酯 石墨负极 密度泛函理论 

分 类 号：TM912[电气工程—电力电子与电力传动]