Logo image
Effect of cation on diffusion coefficient of ionic liquids at onion-like carbon electrodes
Journal article   Peer reviewed

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

Katherine L Van Aken, John K McDonough, Song Li, Guang Feng, Suresh M Chathoth, Eugene Mamontov, Pasquale F Fulvio, Peter T Cummings, Sheng Dai and Yury Gogotsi
Journal of physics. Condensed matter, v 26(28), pp 284104-284104
12 Jun 2014
PMID: 24920163

Abstract

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

Metrics

12 Record Views
55 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Physics, Condensed Matter
Logo image