Capacitive versus Pseudocapacitive Storage in MXene

Yasunobu Ando, Masashi Okubo, Atsuo Yamada, Minoru Otani

Research output: Contribution to journalArticlepeer-review

Abstract

MXene electrodes in electrochemical capacitors have a distinctive behavior that is both capacitive and pseudocapacitive depending on the electrolyte. In this work, to better understand their electrochemical mechanism, first-principles calculations based on the density functional theory combined with the implicit solvation model are used (termed as 3D reference-interaction-site model). From the viewpoint of their electronic states, the hydration shell prevents orbital coupling between MXene and the intercalated ions, which leads to the formation of an electric-double layer and capacitive behavior. However, once the cations are partially dehydrated and adsorbed onto the MXene surface, because of orbital coupling of the cation states with the MXene states, particularly for surface-termination groups, charge transfer occurs and results in a pseudocapacitive behavior.

Original languageEnglish
Article number2000820
JournalAdvanced Functional Materials
Volume30
Issue number47
DOIs
Publication statusPublished - 2020 Nov 18
Externally publishedYes

Keywords

  • MXenes
  • density functional theory
  • pseudocapacitors
  • reference-interaction-site model
  • supercapacitors

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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