Effect of cation on diffusion coefficient of ionic liquids at onion-like carbon electrodes

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Katherine L. Van Aken
  • John K. McDonough
  • Song Li
  • Guang Feng
  • Suresh M. Chathoth
  • And 5 others
  • Eugene Mamontov
  • Pasquale F. Fulvio
  • Peter T. Cummings
  • Sheng Dai
  • Yury Gogotsi

Detail(s)

Original languageEnglish
Article number284104
Journal / PublicationJournal of Physics: Condensed Matter
Volume26
Issue number28
Online published12 Jun 2014
Publication statusPublished - 16 Jul 2014

Abstract

While most supercapacitors are limited in their performance by the stability of the electrolyte, using neat ionic liquids (ILs) as the electrolyte can expand the voltage window and temperature range of operation. In this study, ILs with bis(trifluoromethylsulfonyl)imide (Tf2N) as the anion were investigated as the electrolyte in onion-like carbon-based electrochemical capacitors. To probe the influence of cations on the electrochemical performance of supercapacitors, three different cations were used: 1-ethyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium and 1,6-bis(3-methylimidazolium-1-yl). A series of electrochemical characterization tests was performed using cyclic voltammetry (CV), galvanostatic cycling and electrochemical impedance spectroscopy (EIS). Diffusion coefficients were measured using EIS and correlated with quasielastic neutron scattering and molecular dynamics simulation. These three techniques were used in parallel to confirm a consistent trend between the three ILs. It was found that the IL with the smaller sized cation had a larger diffusion coefficient, leading to a higher capacitance at faster charge-discharge rates. Furthermore, the IL electrolyte performance was correlated with increasing temperature, which limited the voltage stability window and led to the formation of a solid electrolyte interphase on the carbon electrode surface, evident in both the CV and EIS experiments.

Research Area(s)

  • diffusion coefficient, electrochemical capacitor, ionic liquids, onion-like carbons, solid electrolyte interphase

Citation Format(s)

Effect of cation on diffusion coefficient of ionic liquids at onion-like carbon electrodes. / Van Aken, Katherine L.; McDonough, John K.; Li, Song; Feng, Guang; Chathoth, Suresh M.; Mamontov, Eugene; Fulvio, Pasquale F.; Cummings, Peter T.; Dai, Sheng; Gogotsi, Yury.

In: Journal of Physics: Condensed Matter, Vol. 26, No. 28, 284104, 16.07.2014.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal