Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Navaratnarajah Kuganathan, James Dark, E.N. Sgourou, Yerassimos Panayiotatos, Alexander Chroneos

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Abstract

Lithium aluminate, LiAlO2, is a material that is presently being considered as a tritium breeder material in fusion reactors and coating material in Li-conducting electrodes. Here, we employ atomistic simulation techniques to show that the lowest energy intrinsic defect process is the cation anti-site defect (1.10 eV per defect). This was followed closely by the lithium Frenkel defect (1.44 eV per defect), which ensures a high lithium content in the material and inclination for lithium diffusion from formation of vacancies. Li self-diffusion is three dimensional and exhibits a curved pathway with a migration barrier of 0.53 eV. We considered a variety of dopants with charges +1 (Na, K and Rb), +2 (Mg, Ca, Sr and Ba), +3 (Ga, Fe, Co, Ni, Mn, Sc, Y and La) and +4 (Si, Ge, Ti, Zr and Ce) on the Al site. Dopants Mg2+ and Ge4+ can facilitate the formation of Li interstitials and Li vacancies, respectively. Trivalent dopants Fe3+, Ni3+ and Mn3+ prefer to occupy the Al site with exoergic solution energies meaning that they are candidate dopants for the synthesis of Li (Al, M) O2 (M = Fe, Ni and Mn) compounds
Original languageEnglish
Article number2895
Number of pages10
JournalEnergies
Volume12
Issue number15
DOIs
Publication statusPublished - 27 Jul 2019

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Bibliographical note

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Keywords

  • LiAlO2
  • defects
  • Li diffusion
  • dopants
  • atomistic simulation

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