Size-Dependent Physical and Electrochemical Properties of Two-Dimensional MXene Flakes

Kathleen Maleski, Chang E. Ren, Meng Qiang Zhao, Babak Anasori, Yury Gogotsi

Research output: Contribution to journalArticlepeer-review

259 Scopus citations

Abstract

Two-dimensional (2D) particles, including transition metal carbides (MXenes), often exhibit large lateral-size polydispersity in delaminated colloidal solutions. This heterogeneity results in challenges when conducting fundamental studies, such as investigating correlations between properties and the 2D flake size. To resolve this challenge, we have developed solution-processable techniques to control and sort 2D titanium carbide (Ti3C2Tx) MXene flakes after synthesis based on sonication and density gradient centrifugation, respectively. By tuning the sonication conditions, Ti3C2Tx flakes with varied lateral sizes, ranging from 0.1 to ∼5 μm, can be obtained. Furthermore, density gradient centrifugation was used to sort Ti3C2Tx flakes with different lateral sizes into more monodisperse fractions. These processing techniques allow for the characterization of size-dependent optical and electronic properties by measuring the absorption spectra and film conductivity, respectively. Additionally, by testing the material as electrochemical capacitor electrodes, we show the Ti3C2Tx flake-size dependence of electrochemical performance. Ti3C2Tx films made of flakes with lateral sizes of ∼1 μm showed the best capacitance of 290 F/g at 2 mV/s and rate performance with 200 F/g at 1000 mV/s. The work provides a general methodology which can be followed to control the size of MXenes and other 2D materials for a variety of applications and fundamental size-dependent studies.

Original languageEnglish (US)
Pages (from-to)24491-24498
Number of pages8
JournalACS Applied Materials and Interfaces
Volume10
Issue number29
DOIs
StatePublished - Jul 25 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science

Keywords

  • MXene
  • density gradient centrifugation
  • flake size
  • sonication
  • two-dimensional material

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