物理化学学报 >> 2012, Vol. 28 >> Issue (04): 818-822.doi: 10.3866/PKU.WHXB201201132

电化学和新能源 上一篇    下一篇

过充电保护添加剂1,4-二甲氧基苯的反应机理

李田田1, 王朝阳1, 邢丽丹1, 李伟善1,2,3, 彭彬1, 许梦清1,2,3, 顾凤龙1,2,3, 胡社军1,2,3   

  1. 1. 华南师范大学化学与环境学院, 广州 510006;
    2. 华南师范大学, 广东高校电化学储能与发电技术重点实验室, 广州 510006;
    3. 华南师范大学, 电化学储能材料与技术教育部工程研究中心, 广州 510006
  • 收稿日期:2011-10-31 修回日期:2012-01-03 发布日期:2012-03-21
  • 通讯作者: 李伟善 E-mail:liwsh@scnu.edu.cn
  • 基金资助:

    国家自然科学基金-广东省人民政府自然科学联合基金(U1134002)和广东省自然科学基金(10351063101000001)资助项目

Reaction Mechanism of 1,4-Dimethoxy Benzene as an Overcharge Protection Additive

LI Tian-Tian1, WANG Chao-Yang1, XING Li-Dan1, LI Wei-Shan1,2,3, PENG Bin1, XU Meng-Qing1,2,3, GU Feng-Long1,2,3, HU She-Jun1,2,3   

  1. 1. School of Chemistry and Environment, South China Normal University, Guangzhou 510006, P. R. China;
    2. Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006, P. R. China;
    3. Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006, P. R. China
  • Received:2011-10-31 Revised:2012-01-03 Published:2012-03-21
  • Contact: LI Wei-Shan E-mail:liwsh@scnu.edu.cn
  • Supported by:

    The project was supported by the Joint Project of National Natural Science Foundation of China and Natural Science Foundation of Guangdong Province (U1134002) and Natural Science Foundation of Guangdong Province, China (10351063101000001).

摘要: 采用密度泛函理论(B3LYP/6-311+G(d,p))和MP2/6-311+G(d,p)方法, 研究锂离子电池过充电保护添加剂1,4-二甲氧基苯(p-DMOB)的作用机理. 计算结果表明, 在过充时, p-DMOB优先于溶剂分子(乙基甲基碳酸酯、二甲基碳酸酯、碳酸乙酯)发生氧化反应. 用B3LYP和MP2计算所得的p-DMOB理论氧化电位接近, 分别为4.12和4.05 V (vs Li/Li+). p-DMOB氧化时首先失去一个电子, 生成p-DMOB正离子自由基, 用B3LYP和MP2方法计算所得的相应能量变化分别为701.24 和728.27 kJ·mol-1. 失去电子后苯环的共轭性受到破坏, 随后p-DMOB苯环上的C―H键发生断裂, 失去H+并形成p-DMOB·自由基. 用B3LYP和MP2 方法计算所得的相应能量变化分别为1349.78和1810.99 kJ·mol-1. p-DMOB·自由基很不稳定, 会在电极表面发生聚合反应形成聚合物膜, 用B3LYP和MP2方法计算所得的相应能量变化分别为-553.37和-1331.20 kJ·mol-1.

关键词: 锂离子电池, 过充电保护添加剂, 1,4-二甲氧基苯, 反应机理, 密度泛函理论

Abstract: The reaction mechanism of 1,4-dimethoxybenzene (p-DMOB) as an overcharge protection additive for lithium ion batteries was determined by theoretical calculation of density functional theory (DFT) at the level of B3LYP/6-311+G(d,p) and MP2/6-311+G(d,p). It was found that p-DMOB is oxidized prior to the solvents, ethyl methyl carbonate, dimethyl carbonate, and ethylene carbonate, when the lithium ion battery is overcharged. The calculated oxidative potentials of p-DMOB by B3LYP and MP2 methods are well in agreement at 4.12 and 4.05 V (vs Li/Li), respectively. The initial oxidation of p-DMOB involves a one-electron transfer resulting in a radical cation p-DMOB. The corresponding energy variations were 701.24 and 728.27 kJ·mol-1 from B3LYP and MP2 calculations, respectively. The p-DMOB species then loses one proton forming a radical p-DMOB·through the breaking of a C―H bond on the benzene ring, with the corresponding energy variations of 1349.78 and 1810.99 kJ·mol-1 for B3LYP and MP2, respectively. The p-DMOB·species is unstable and copolymerizes forming an insulated polymer with the corresponding energy variations of -553.37 and -1331.20 kJ·mol-1 for B3LYP and MP2, respectively.

Key words: Lithium ion battery, Overcharge protection additive, 1,4-Dimethoxy benzene, Reaction mechanism, Density functional theory

MSC2000: 

  • O646