中国物理B ›› 2020, Vol. 29 ›› Issue (4): 48202-048202.doi: 10.1088/1674-1056/ab75cc

所属专题: SPECIAL TOPIC — Advanced calculation & characterization of energy storage materials & devices at multiple scale

• SPECIAL TOPIC—Recent advances in thermoelectric materials and devices • 上一篇    下一篇

Comparative calculation on Li+ solvation in common organic electrolyte solvents for lithium ion batteries

Qi Liu(刘琦), Feng Wu(吴锋), Daobin Mu(穆道斌), Borong Wu(吴伯荣)   

  1. Beijing Key Laboratory of Environment Science and Engineering, School of Material Science and Engineering, Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing Institute of Technology, Beijing 100081, China
  • 收稿日期:2019-10-06 修回日期:2020-02-08 出版日期:2020-04-05 发布日期:2020-04-05
  • 通讯作者: Feng Wu, Daobin Mu E-mail:wufeng863@vip.sina.com;mudb@bit.edu.cn
  • 基金资助:
    Project supported by International Science & Technology Cooperation of China (Grant No. 2019YFE0100200), the National Natural Science Foundation of China (Grant No. 51902024), the National Postdoctoral Program for Innovative Talents of China (Grant No. BX20180038), China Postdoctoral Science Foundation (Grant No. 2019M650014), NASF, China (Grant No. U1930113), and Beijing Natural Science Foundation, China (Grant No. L182022).

Comparative calculation on Li+ solvation in common organic electrolyte solvents for lithium ion batteries

Qi Liu(刘琦), Feng Wu(吴锋), Daobin Mu(穆道斌), Borong Wu(吴伯荣)   

  1. Beijing Key Laboratory of Environment Science and Engineering, School of Material Science and Engineering, Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing Institute of Technology, Beijing 100081, China
  • Received:2019-10-06 Revised:2020-02-08 Online:2020-04-05 Published:2020-04-05
  • Contact: Feng Wu, Daobin Mu E-mail:wufeng863@vip.sina.com;mudb@bit.edu.cn
  • Supported by:
    Project supported by International Science & Technology Cooperation of China (Grant No. 2019YFE0100200), the National Natural Science Foundation of China (Grant No. 51902024), the National Postdoctoral Program for Innovative Talents of China (Grant No. BX20180038), China Postdoctoral Science Foundation (Grant No. 2019M650014), NASF, China (Grant No. U1930113), and Beijing Natural Science Foundation, China (Grant No. L182022).

摘要: It is important for the electrolytes to maintain and enhance the lithium ion battery electrochemical performance, and solvation of Li+ is a key parameter for the property of the electrolytes. The comparative study on Li+ solvation structures, energy, enthalpy, Gibbs free energy, infrared and Raman spectra in common organic electrolyte solvents is completed by density functional theory (DFT) method. The solvation reaction energy results suggest that the Li+ solvation priority order is propylene carbonate (PC) > ethylene carbonate (EC) > ethyl methyl carbonate (EMC) > diethyl carbonate (DEC) > tetrahydrofuran (THF) > dimethyl carbonate (DMC) > 1,3-dioxolane (DOL) > dimethoxyethane (DME) to form 5sol-Li+. It is also indicated that the most innermost solvation shell compounds formations by stepwise spontaneous solvation reaction are four cyclic solvent molecules and three linear solvent molecules combining one Li+ forming 4sol-Li+ and 3sol-Li+, respectively, at room temperature. Besides, the vibration peaks for C=O and C-O bonds in carbonate ester solvents-Li+ compounds shift to lower frequency and higher frequency, respectively, when the Li+ concentration increases in the solvation compounds. All Li-O stretching vibration peaks shift to higher frequency until forming 2solvent-Li+ complexes, and C-H stretching also shifts to higher frequency except for nDME-Li+ solvation compounds. The Raman spectrum is more agile to characterize C-H vibrations and IR is agile to C=O, C-O, and Li-O vibrations for Li+ solvation compounds.

关键词: Li+ solvation, frequency shift, infrared spectra, Raman spectra

Abstract: It is important for the electrolytes to maintain and enhance the lithium ion battery electrochemical performance, and solvation of Li+ is a key parameter for the property of the electrolytes. The comparative study on Li+ solvation structures, energy, enthalpy, Gibbs free energy, infrared and Raman spectra in common organic electrolyte solvents is completed by density functional theory (DFT) method. The solvation reaction energy results suggest that the Li+ solvation priority order is propylene carbonate (PC) > ethylene carbonate (EC) > ethyl methyl carbonate (EMC) > diethyl carbonate (DEC) > tetrahydrofuran (THF) > dimethyl carbonate (DMC) > 1,3-dioxolane (DOL) > dimethoxyethane (DME) to form 5sol-Li+. It is also indicated that the most innermost solvation shell compounds formations by stepwise spontaneous solvation reaction are four cyclic solvent molecules and three linear solvent molecules combining one Li+ forming 4sol-Li+ and 3sol-Li+, respectively, at room temperature. Besides, the vibration peaks for C=O and C-O bonds in carbonate ester solvents-Li+ compounds shift to lower frequency and higher frequency, respectively, when the Li+ concentration increases in the solvation compounds. All Li-O stretching vibration peaks shift to higher frequency until forming 2solvent-Li+ complexes, and C-H stretching also shifts to higher frequency except for nDME-Li+ solvation compounds. The Raman spectrum is more agile to characterize C-H vibrations and IR is agile to C=O, C-O, and Li-O vibrations for Li+ solvation compounds.

Key words: Li+ solvation, frequency shift, infrared spectra, Raman spectra

中图分类号:  (Electrochemistry and electrophoresis)

  • 82.45.-h
78.30.-j (Infrared and Raman spectra)