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Enhancing High‐Rate Capability by Introducing Phosphonate Functionalized Imidazolium Ionic Liquid into Organic Carbonate Electrolyte
Author(s) -
Zhao Kun,
Liang Hongze,
Zhou Mingjiong,
Zhang Gongjun,
Zhao Chuanli,
Ge Jiawen,
Xia Yonggao,
Gao Zhanghua
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201800214
Subject(s) - phosphonate , electrolyte , ionic liquid , fourier transform infrared spectroscopy , electrochemistry , faraday efficiency , lithium (medication) , ion , inorganic chemistry , chemistry , solvation , chemical engineering , materials science , electrode , organic chemistry , catalysis , medicine , engineering , endocrinology
A phosphonate functionalized imidazolium ionic liquid (PFIL) is synthesized and studied as an electrolyte additive for lithium ion batteries. The Li/LiFePO 4 cells with addition of PFIL shows superior electrochemical performance, including an increased initial Coulombic efficiency, better capacity retention, and improved rate capability. The electrochemical mechanism of PFIL used in high‐performance batteries is investigated by using fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Our experimental result reveals that the phosphonate groups are stronger donors than carbonate groups, thus change the solvation environment of lithium ions by competitive coordination, assisting the transferring of lithium ions. Therefore, an excellent cyclability and superior rate capability with PFIL‐based electrolyte could be explained by enhanced mobility lithium ions via coordination to phosphonate groups on imidazolium cations. This work displays that PFIL‐based electrolyte systems can be considerable potential candidates for the applications in high‐performance Li‐ion batteries.