Relationship between Electric Double-Layer Structure of MXene Electrode and Its Surface Functional Groups

Tatau Shimada, Norio Takenaka, Yasunobu Ando, Minoru Otani, Masashi Okubo, Atsuo Yamada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

MXenes are emerging electrode materials intended for electric double-layer capacitors because of their large specific capacitance of more than 300 F/g. Recent advances in synthesis methods have enabled a decrease in surface functional groups and chemical control of their design, but the influence of surface functional groups on capacitive properties is still unclear. Here, we applied density functional theory combined with effective screening medium and reference interaction site model calculations to systematically investigate the atomic-scale double-layer structure of Ti3C2T2MXene electrodes depending on their terminated halogen elements. The termination with halogen atoms having larger atomic numbers (I > Br > Cl > F) increased the electric double-layer capacitance. The increased capacitance originates from the smaller valence electron numbers of the terminating atoms with lower electronegativity that facilitate the electrostatic accumulation of electrons at the electrode surface. Such a solid trend provides a basis for consideration in designing MXene surfaces with larger capacitance.

Original languageEnglish
Pages (from-to)2069-2075
Number of pages7
JournalChemistry of Materials
Volume34
Issue number5
DOIs
Publication statusPublished - 2022 Mar 8
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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