A Computational Study of Defects, Li-Ion Migration and Dopants in Li2ZnSiO4 Polymorphs

Dilki Perera, Sashikesh Ganeshalingam, Navaratnarajah Kuganathan, Alexander Chroneos

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Abstract

Lithium zinc silicate, Li2ZnSiO4, is a promising ceramic solid electrolyte material for Li-ion batteries. In this study, atomistic simulation techniques were employed to examine intrinsic defect processes; long range Li-ion migration paths, together with activation energies; and candidate substitutional dopants at the Zn and the Si sites in both monoclinic and orthorhombic Li2ZnSiO4 phases. The Li-Zn anti-site defect is the most energetically favourable defect in both phases, suggesting that a small amount of cation mixing would be observed. The Li Frenkel is the second lowest energy process. Long range Li-ion migration is observed in the ac plane in the monoclinic phase and the bc plane in the orthorhombic phase with activation energies of 0.88 eV and 0.90 eV, respectively, suggesting that Li-ion diffusivities in both phases are moderate. Furthermore, we show that Fe3+ is a promising dopant to increase Li vacancies required for vacancy-mediated Li-ion migration, and that Al3+ is the best dopant to introduce additional Li in the lattice required for increasing the capacity of this material. The favourable isovalent dopants are Fe2+ at the Zn site and Ge4+ at the Si site.
Original languageEnglish
Article number563
Number of pages13
Journalcrystals
Volume9
Issue number11
DOIs
Publication statusPublished - 27 Oct 2019

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defects
ions
activation energy
solid electrolytes
diffusivity
electric batteries
silicates
lithium
zinc
ceramics
cations
simulation
energy

Bibliographical note

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Keywords

  • Atomistic simulation
  • Defects
  • Dopants
  • Li ZnSiO
  • Li-ion diffusion

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

Cite this

A Computational Study of Defects, Li-Ion Migration and Dopants in Li2ZnSiO4 Polymorphs. / Perera, Dilki; Ganeshalingam, Sashikesh; Kuganathan, Navaratnarajah; Chroneos, Alexander.

In: crystals, Vol. 9, No. 11, 563, 27.10.2019.

Research output: Contribution to journalArticle

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