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Title: Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries

Abstract

A bicyclic imidazolium ionic liquids, 1-ethyl-2,3-trimethyleneimidazolium bis(tri fluoromethane sulfonyl)imide ([ETMIm][TFSI]), and reference imidazolium compounds, 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([EMIm][TFSI]) and 1, 2-dimethyl-3-butylimidazolium bis(trifluoromethane sulfonyl)imide ([DMBIm][TFSI]), were synthesized and investigated as solvents for lithium ion batteries. Although the alkylation at the C-2 position of the imidazolium ring does not affect the thermal stability of the ionic liquids, with or without the presence of 0.5 molar lithium bis(trifluoromethane sulfonyl)imide (LiTFSI), the stereochemical structure of the molecules has shown profound influences on the electrochemical properties of the corresponding ionic liquids. [ETMIm][TFSI] shows better reduction stability than do [EMIm][TFSI] and [DMBIm][TFSI], as confirmed by both linear sweep voltammery (LSV) and theoretical calculation. The Li||Li cell impedance of 0.5M LiTFSI/[ETMIm][TFSI] is stabilized, whereas that of 0.5M LiTFSI/[DMBIm][TFSI] is still fluctuating after 20 hours, indicating a relatively stable solid electrolyte interphase (SEI) is formed in the former. Furthermore, the Li||graphite half-cell based on 0.5M LiTFSI/[BTMIm][TFSI] exhibits reversible capacity of 250mAh g-1 and 70mAh g-1 at 25 C, which increases to 330 mAh g-1 and 250 mAh g-1 at 50 C, under the current rate of C/20 and C/10, respectively. For comparison, the Li||graphite half-cell based on 0.5M LiTFSI/[DMBIm][TFSI] exhibits poor capacity retention under the same current ratemore » at both temperatures.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1090490
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 237
Country of Publication:
United States
Language:
English
Subject:
Lithium ion battery; 1-ethyl-2; 3-trimethyleneimidazolium bis(trifluoromethane sulfonyl)imide ([ETMIm][TFSI]); solid electrolyte interphase (SEI); impedance spectroscopy

Citation Formats

Liao, Chen, Shao, Nan, Bell, Jason R, Guo, Bingkun, Luo, Huimin, Jiang, Deen, and Dai, Sheng. Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries. United States: N. p., 2013. Web.
Liao, Chen, Shao, Nan, Bell, Jason R, Guo, Bingkun, Luo, Huimin, Jiang, Deen, & Dai, Sheng. Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries. United States.
Liao, Chen, Shao, Nan, Bell, Jason R, Guo, Bingkun, Luo, Huimin, Jiang, Deen, and Dai, Sheng. Tue . "Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries". United States.
@article{osti_1090490,
title = {Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries},
author = {Liao, Chen and Shao, Nan and Bell, Jason R and Guo, Bingkun and Luo, Huimin and Jiang, Deen and Dai, Sheng},
abstractNote = {A bicyclic imidazolium ionic liquids, 1-ethyl-2,3-trimethyleneimidazolium bis(tri fluoromethane sulfonyl)imide ([ETMIm][TFSI]), and reference imidazolium compounds, 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([EMIm][TFSI]) and 1, 2-dimethyl-3-butylimidazolium bis(trifluoromethane sulfonyl)imide ([DMBIm][TFSI]), were synthesized and investigated as solvents for lithium ion batteries. Although the alkylation at the C-2 position of the imidazolium ring does not affect the thermal stability of the ionic liquids, with or without the presence of 0.5 molar lithium bis(trifluoromethane sulfonyl)imide (LiTFSI), the stereochemical structure of the molecules has shown profound influences on the electrochemical properties of the corresponding ionic liquids. [ETMIm][TFSI] shows better reduction stability than do [EMIm][TFSI] and [DMBIm][TFSI], as confirmed by both linear sweep voltammery (LSV) and theoretical calculation. The Li||Li cell impedance of 0.5M LiTFSI/[ETMIm][TFSI] is stabilized, whereas that of 0.5M LiTFSI/[DMBIm][TFSI] is still fluctuating after 20 hours, indicating a relatively stable solid electrolyte interphase (SEI) is formed in the former. Furthermore, the Li||graphite half-cell based on 0.5M LiTFSI/[BTMIm][TFSI] exhibits reversible capacity of 250mAh g-1 and 70mAh g-1 at 25 C, which increases to 330 mAh g-1 and 250 mAh g-1 at 50 C, under the current rate of C/20 and C/10, respectively. For comparison, the Li||graphite half-cell based on 0.5M LiTFSI/[DMBIm][TFSI] exhibits poor capacity retention under the same current rate at both temperatures.},
doi = {},
journal = {Journal of Power Sources},
number = ,
volume = 237,
place = {United States},
year = {2013},
month = {1}
}