Alkylimidazolium-based ionic liquids as lithium-ion battery electrolyte

作者：Yang Wenzhong^*; Zhuang Cheng; Wang Jintang; Shi Yuanxiang

来源：Asian Journal of Chemistry, 2008, 20(5): 3507-3514.

• room temperature ionic liquid
• electrolyte
• lithium-ion battery
• LiCoO2 cathode

The two alkylimidazolium-based ionic liquids of 1-methyl-3-methylimidazolium tetrafluoroborate (EMIBF4) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) are synthesized and their electrochemical properties are investigated by using cyclic voltammetry and galvanostatic charge-discharge techniques. The results reveal that the electrochemical windows of these two ionic liquids are both about 4.3 V and their ionic conductivity are 13.7 and 3.0 mS/cm respectively at 25 degrees C. The demonstration battery with graphite anode and LiCoO2 cathode are prepared by using EMIBF4, BMIBF4 and I mol L-1LiPF6 as electrolyte and 5 % of vinylene carbonate (VC) as additive. The coulombic efficiency of the EMIBF4-involved electrolyte is up to 90 % after 50 cycles and the capacity remaines above 91 mAhmg(-1) during the whole cycle, while the coulombic efficiency of the BMIBF4-based battery droppes directly after 10 cycles. The capacity of the EMIBF4-based battery with C/5 rate is 80 % of C/15 rate in 25 degrees C.

• 出版日期2008-6
• 单位南京工业大学