• 文献标题:   EMIMBF4-GBL binary electrolyte working at-70 degrees C and 3.7 V for a high performance graphene-based capacitor
  • 文献类型:   Article
  • 作  者:   TIAN JR, CUI CJ, XIE Q, QIAN WZ, XUE C, MIAO YH, JIN Y, ZHANG G, GUO BH
  • 作者关键词:  
  • 出版物名称:   JOURNAL OF MATERIALS CHEMISTRY A
  • ISSN:   2050-7488 EI 2050-7496
  • 通讯作者地址:   Tsinghua Univ
  • 被引频次:   9
  • DOI:   10.1039/c7ta10474j
  • 出版年:   2018

▎ 摘  要

Developing an ionic-liquid (IL) type electrolyte with both high voltage window and wide temperature window, especially the low temperature range, is crucial to increase the energy density of the associated electrical double layer capacitors. We proposed the addition of g-butyrolactone (GBL) in EMIMBF4 to form a binary electrolyte. The melting point (similar to 15 degrees C) of EMIMBF4 disappeared and the glass transition point decreased from -95 degrees C (for pure EMIMBF4) to -126 degrees C for the binary electrolyte. The binary electrolyte also exhibited improved ionic conductivity (26 and 0.31 mS cm(-1) at 20 and -70 degrees C, respectively) and allowed an electrode of mesoporous graphene to exhibit a capacitance of 131 F g(-1) and energy density of 61 W h kg (1) at -70 degrees C and 3.7 V, the highest values reported so far. NMR and ATR-IR characterization validated the strong interaction between GBL and EMIMBF4 for breaking the ion pairs of the latter but without forming the solvated ions, as in the system of EMMIBF4 with propylene carbonate.