3, 4-Ethylenedioxythiophene Monomer as Safety-Enhancing Additive for Lithium Ion Batteries

Authors

Wei-xiao JI, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;
Feng WANG, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;
Jiang-feng QIAN, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;
Yu-liang CAO, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;
Xin-ping AI, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;Follow
Han-xi YANG, Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China;

Corresponding Author

Xin-ping AI(xpai@whu.edu.cn)

Abstract

Safety concern is a major obstacle hindering the wide applications of large-capacity lithium ion batteries (LIBs) in electric vehicles. In this paper, a polymerizable monomer of 3, 4-ethylenedioxythiophene (EDOT) was proposed and tested as an electrolyte additive for enhancing the safety of LIBs. The electro-oxidative polymerization behaviors and influence of PEDOT additive on the thermal behavior of LiCoO₂ cathode, as well as the safety performance and electrochemical properties of LiCoO₂-based LIBs were investigated. The results from cyclic voltammetry (CV) and transmission electron microscope (TEM) characterizations indicated that the monomer additive can be electro-oxidatively polymerized to form a dense and uniform conductive polymer film (PEDOT) on the cathode surface during the first battery charging. The analysis results from differential scanning calorimetry (DSC) demonstrated that the heat released from the thermal decomposition of liquid electrolyte on the cathode surface was significantly reduced by 26 % due to the PEDOT barrier layer, which prevents electrolyte from direct contact with highly oxidative cathode. The safety tests revealed that even with a monomer content of only 0.1 wt% in liquid electrolyte, the thermal runaway onset time of LiCoO₂-based pouch full cells could be delayed for 13.8 min under high temperature impact at 150 ^oC, representing a significantly enhanced safety. In addition, it is also found that the use of EDOT monomer as an electrolyte additive did not produce any negative influence on the normal charge-discharge performance of LIBs, showing a prospect for battery application.

Graphical Abstract

Keywords

safety additive, lithium ion battery, electro-oxidative polymerization, conducting polymer, 3, 4-ethylenedioxythiophene monomer.

DOI Link

https://doi.org/10.13208/j.electrochem.151244

Publication Date

2016-06-28

Online Available Date

2016-01-25

Revised Date

2016-01-19

Received Date

2015-12-29

Recommended Citation

Wei-xiao JI, Feng WANG, Jiang-feng QIAN, Yu-liang CAO, Xin-ping AI, Han-xi YANG. 3, 4-Ethylenedioxythiophene Monomer as Safety-Enhancing Additive for Lithium Ion Batteries[J]. Journal of Electrochemistry, 2016 , 22(3): 271-277.
DOI: 10.13208/j.electrochem.151244
Available at: https://jelectrochem.xmu.edu.cn/journal/vol22/iss3/6