Highly Enhanced Pseudocapacitive Performance of Vanadium-Doped MXenes in Neutral Electrolytes

Zhi Wen Gao, Weiran Zheng, Lawrence Yoon Suk Lee (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)

Abstract

2D titanium carbide (Ti3C2Tx MXene) is recognized as a promising material for pseudocapacitor electrodes in acidic solutions, while the current studies in neutral electrolytes show much poorer performances. By a simple hydrothermal method, vanadium-doped Ti3C2Tx 2D nanosheets are prepared to tune the interaction between MXene and alkali metal adsorbates (Li+, Na+, and K+) in the neutral electrolyte. Maintaining the 2D morphology of MXene, the coexisting V3+ and V4+ are confirmed to form surface V–C and V–O species. At a medium doping level of V:Ti = 0.17:1, the V-doped MXene exhibits the highest capacitance of 365.9 F g−1 in 2 m KCl (10 mV s−1) and excellent stability (5% loss after 5000 cycles), compared to only 115.7 F g−1 of pristine MXene. Density functional theory calculations reveal the stronger alkali metal ion–O interaction on V-doped MXene surface than unmodified MXene and a further capacitance boost to 404.9 F g−1 using Li+-containing neutral electrolyte is reported, which is comparable to the performance under acidic conditions.

Original languageEnglish
Article number1902649
JournalSmall
Volume15
Issue number40
DOIs
Publication statusPublished - 1 Oct 2019

Keywords

  • neutral electrolytes
  • pseudocapacitors
  • strong interaction
  • TiCT MXene
  • vanadium doping

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

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