Pyrrolinium-based Ionic Liquid as a Flame Retardant for Binary Electrolytes of Lithium Ion Batteries
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- 作者：Hyung-Tae Kim ; Jaesik Kang ; Junyoung Mun ; Seung M. Oh ; Taeeun Yim ; Young Gyu Kim
- 刊名：ACS Sustainable Chemistry & Engineering
- 出版年：2016
- 出版时间：February 1, 2016
- 年：2016
- 卷：4
- 期：2
- 页码：497-505
- 全文大小：586K
- ISSN：2168-0485
文摘
Ionic liquid (IL)-based electrolytes have attracted much attention to enable safe lithium ion batteries (LIBs) owing to their inflammability and thermal stability as well as their high conductivity and wide electrochemical stability. However, because of the interruption of lithium ion mobility during a charge/discharge process, ILs as the only electrolyte solvent could not be efficient. To improve both the lithium ion mobility and the safety issue of LIBs, we suggest new binary electrolytes that consist of pyrrolinium-based IL and commercial carbonate. The pyrrolinium-based IL is characterized by some task-specific functionalities such as a planar sp2 carbon of double bond, a Li+-binding C–O ether linkage, and no unstable C–H bond, which would provide better physicochemical and electrochemical properties than the known imidazolium- or pyrrolidinium-based ILs. On the basis of the material design, the binary electrolyte systems composed of the pyrrolinium-based IL (N-ethyl-2-methoxypyrrolinium bis(fluorosulfonyl)imide, E(OMe)Pyrl-FSI) and commercial carbonate electrolyte (1.0 M LiPF6 in EC/EMC = 3/7 with 3 wt % VC) were investigated. As a result, the proposed pyrrolinium-based binary electrolyte systems showed the improved properties as an electrolyte for LiFePO4 electrode as follows; (i) the ionic conductivity of some binary electrolyte systems was better than that of the 100 wt % IL or the 100 wt % carbonate-based electrolyte (ii) the significant suppression of the flammability of the binary electrolytes was observed (iii) the comparable cycle life of the binary electrolytes to that of the commercial carbonate electrolyte was maintained even at high rate performance (1 C).