Interfacial dissociation of contact-ion-pair on MXene electrodes in concentrated aqueous electrolytes

Kijae Kim, Masashi Okubo, Atsuo Yamada

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

An aqueous supercapacitor is a prospective energy storage device that achieves affordable clean-energy supply. Although recent intensive research on concentrated electrolytes paved the way to improve its low energy density by expanding the narrow electrochemical potential window of water, it was compromised by slow rate capability with respect to the capacitor standard. In this work, to reveal the rate-determining ion-transport mechanism that limits the reaction kinetics of aqueous capacitor electrodes, electrochemical impedance spectroscopy was conducted on layered titanium carbide (MXene) electrodes with concentrated aqueous electrolytes (water-in-salt and hydrate melt). With increasing salt concentration, the dissociation of contact-ion-pair becomes dominant to ion transport both in the bulk electrolyte and at the electrode-electrolyte interface.

Original languageEnglish
Pages (from-to)A3739-A3744
JournalJournal of the Electrochemical Society
Volume166
Issue number15
DOIs
Publication statusPublished - 2019
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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