Defects, diffusion and dopants in Li8SnO6

Navaratnarajah Kuganathan; Andrei L Solovjov; Ruslan V Vovk; Alexander Chroneos

doi:10.1016/j.heliyon.2021.e07460

Defects, diffusion and dopants in Li₈SnO₆

Heliyon. 2021 Jul 2;7(7):e07460. doi: 10.1016/j.heliyon.2021.e07460. eCollection 2021 Jul.

Authors

Navaratnarajah Kuganathan^{1

2}, Andrei L Solovjov³, Ruslan V Vovk⁴, Alexander Chroneos^{1

2}

Affiliations

¹ Department of Materials, Imperial College London, London, SW7 2AZ, United Kingdom.
² Faculty of Engineering, Environment and Computing, Coventry University, Priory Street, Coventry, CV1 5FB, United Kingdom.
³ B. Verkin Institute for Low Temperature Physics and Engineering, NAS of Ukraine, 47 Nauky Avenue, Kharkiv, 61103, Ukraine.
⁴ V. Karazin Kharkiv National University, 4 Svobody Square, Kharkiv, 61077, Ukraine.

Abstract

Octalithium tin (IV) oxide (Li₈SnO₆) is an important electrode material considered for lithium ion batteries (LIBs) because of its high lithium content. We employed atomistic simulations to examine the intrinsic defects, diffusion of Li-ions together with their migration energies and solution of potential dopants in Li₈SnO₆. The most thermodynamically favourable intrinsic defect is the Li Frenkel which increases the concentration of Li vacancies needed for the vacancy mediated diffusion of Li-ions in Li₈SnO₆. The calculated activation energy of migration of Li-ions (0.21eV) shows that the Li-ion conductivity in this material can be very fast. Promising isovalent dopants on the Li and Sn sites are Na and Ti, respectively. Doping of Ga on the Sn site can facilitate the formation of Li interstitials as well as oxygen vacancies in Li₈SnO₆. While the concentration of Li interstitials can enhance the capacity of this material, oxygen vacancies together with Li interstitials can lead to the loss of Li₂O in Li₈SnO₆.

Keywords: Atomistic simulation; Defects; Diffusion; Dopants; Li8SnO6.