Fast-cure ionogel electrolytes with improved ion transport kinetics at room temperature

Ronak Janani, Kerstin Mader, Alexander John Roberts, Nicolas Farmilo, Chris Sammon

Research output: Contribution to journalArticle

Abstract

Fast-cure 1-ethyl-3-methylimidazolium trifluoromethanesulfonate-based ionogels have been realised for the first time. The influence of curing temperature on the structure of ionogels and their performance as the electrolyte for electric double-layer capacitors (EDLCs) has been investigated. Hybrid ionogels were synthesised via a non-hydrolytic sol-gel route and were fully gelled post heat-treating at 125, 150, 175 and 200 °C for 60 min with minimal shrinkage. Charge-transfer resistance (a rate-limiting parameter in cell kinetics during charge/discharge cycles) was reduced by ∼80% by increasing the heat-treatment temperature; this was partially attributed to the interlocking effect facilitated by high curing temperature. We report a maximum areal capacitance of 95 mF cm −2 . Due to ∼40% increase in the penetrability coefficient of the ionic liquid, the electrode ‘full’ wetting time dropped from 48 to 5 h when the curing temperature was increased above 150 °C. These results were supported by SEM and Raman spectroscopy to characterise the effect of high temperature heat-treatment on the electrode-ionogel interface and the degree of electrode wetting by the ionic liquid. The fast-cure fabrication process for ionogels removes one of the major hurdles in their industrial application while the improved room temperature ion transport kinetics expands the potential application of ionic liquid-based electrochemical systems.

Original languageEnglish
Pages (from-to)141-150
Number of pages10
JournalJournal of Power Sources
Volume406
Early online date20 Oct 2018
DOIs
Publication statusPublished - 1 Dec 2018
Externally publishedYes

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Keywords

  • Curing temperature
  • Electrode-electrolyte interface
  • Ionogel
  • Penetrability coefficient
  • Porous electrode
  • Supercapacitor

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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