Density Functional Theory Evaluated for Structural and Electronic Properties of 1T-LixTiS2 and Lithium Ion Migration in 1T-Li0.94TiS2

Vanessa Werth, Kai Volgmann, Mazharul M. Islam, Paul Heitjans, Thomas Bredow

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

In many applications it has been found that the standard generalized gradient approximation (GGA) does not accurately describe weak chemical bond and electronic properties of solids containing transition metals. In this work, we have considered the intercalation material 1T-LixTiS2 (0≤x≤1) as a model system for the evaluation of the accuracy of GGA and corrected GGA with reference to the availabile experimental data. The influence of two different dispersion corrections (D3 and D-TS) and an on-site Coulomb repulsion term (GGA+U) on the calculated structural and electronic properties is tested. All calculations are based on the Perdew-Burke-Ernzerhof (PBE) functional. An effective U value of 3.5 eV is used for titanium. The deviation of the calculated lattice parameter c for TiS2 from experiment is reduced from 14 % with standard PBE to -2 % with PBE+U and Grimme's D3 dispersion correction. 1T-TiS2 has a metallic ground state at PBE level whereas PBE+U predicts an indirect gap of 0.19 eV in agreement with experiment. The 7Li chemical shift and quadrupole coupling constants are in reasonable agreement with the experimental data only for PBE+U-D3. An activation energy of 0.4 eV is calculated with PBE+U-D3 for lithium migration via a tetrahedral interstitial site. This result is closer to experimental values than the migration barriers previously obtained at LDA level. The proposed method PBE+U-D3 gives a reasonable description of structural and electronic properties of 1T-LixTiS2 in the whole range 0≤x≤1.

Original languageEnglish
Pages (from-to)1263-1278
Number of pages16
JournalZeitschrift fur Physikalische Chemie
Volume231
Issue number7-8
Early online date4 May 2017
DOIs
Publication statusPublished - 26 Jul 2017

Keywords

  • band structure
  • chemical shift
  • DFT+U
  • dispersion correction
  • Li ion diffusion
  • lithium titanium disulfide
  • migration barrier
  • quadrupole coupling constant

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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