Defect Chemistry and Li-ion Diffusion in Li2RuO3

Navaratnarajah Kuganathan; Apostolos Kordatos; Alexander Chroneos

doi:10.1038/s41598-018-36865-4

Defect Chemistry and Li-ion Diffusion in Li₂RuO₃

Sci Rep. 2019 Jan 24;9(1):550. doi: 10.1038/s41598-018-36865-4.

Authors

Navaratnarajah Kuganathan¹, Apostolos Kordatos², Alexander Chroneos^{3

4}

Affiliations

¹ Department of Materials, Imperial College London, London, SW7 2AZ, United Kingdom. n.kuganathan@imperial.ac.uk.
² Faculty of Engineering, Environment and Computing, Coventry University, Priory Street, Coventry, CV1 5FB, United Kingdom.
³ Department of Materials, Imperial College London, London, SW7 2AZ, United Kingdom. alexander.chroneos@imperial.ac.uk.
⁴ Faculty of Engineering, Environment and Computing, Coventry University, Priory Street, Coventry, CV1 5FB, United Kingdom. alexander.chroneos@imperial.ac.uk.

Abstract

Layered Li₂RuO₃ is an important candidate cathode material in rechargeable lithium ion batteries because of its novel anionic redox process and high reversible capacity. Atomistic scale simulations are used to calculate the intrinsic defect process, favourable dopants and migration energies of lithium ion diffusions together with migration paths in Li₂RuO₃. The Li Frenkel is calculated to be the most favourable intrinsic defect type. The cation anti-site defect, in which Li and Ru ions exchange their positions is 1.89 eV/defect suggesting that this defect would be observed at high temperatures. Long range vacancy assisted lithium diffusion paths were calculated and it is confirmed that the lowest overall activation energy (0.73 eV) migration path is along the ab plane. Trivalent dopants (Al³⁺, Co³⁺, Sc³⁺, In³⁺, Y³⁺, Gd³⁺ and La³⁺) were considered to create additional Li in Li₂RuO₃. Here we show that Al³⁺ or Co³⁺ are the ideal dopants and this is in agreement with the experimental studies reported on Co³⁺ doping in Li₂RuO₃.