Natural abundance O-17, Li-6 NMR and molecular modeling studies of the solvation structures of lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane liquid electrolytes

作者：Wan, Chuan; Hu, Mary Y.; Borodin, Oleg; Qian, Jiangfeng; Qin, Zhaohai; Zhang, Ji-Guang; Hu, Jian Zhi^*

来源：Journal of Power Sources, 2016, 307: 231-243.

DOI：10.1016/j.jpowsour.2015.12.120

• Natural abundance O-17 and Li-6 NMR
• Molecular modeling studies
• Electrolytes
• Lithium bis(fluorosulfonyl)imide
• 1,2-Dimethoxyethane
• Solvation structure

Natural abundance O-17 and Li-6 NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes. It was found that the chemical shifts of both O-17 and Li-6 changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)(2) forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI- ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI-)(2)(DME), Li-2(+)(FSI-)(DME)(4) and (LiFSI)(2)(DME)(3) become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI- increases, which is in perfect accord with the DFT results.

• 出版日期2016-3-1
• 单位中国农业大学