Jahn–Teller distortion affected Li ion migration in spinel TiO2

• Published in: Solid state ionics Vol. 312; pp. 17 - 20
• Main Authors: Ning, Fanghua, Wang, Hewen, Xu, Bo, Ouyang, Chuying
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2017
• Subjects: First-principles calculation; Jahn–Teller distortion; Li ion migration; Li-ion battery; Li ion migration; First-principles calculation; Jahn–Teller distortion; Li-ion battery
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2017.10.002

In this paper, we study the effect of the Jahn-Teller (JT) distortion on the Li ion migration energy barrier in spinel TiO2 by using first-principles calculations. Our results show that the JT distortion can be beneficial, harmful, and unaffected to the Li ion migration, depending on the Li ion migration pathway and the orientation of the JT distortion. Bond length analysis demonstrates that the JT distortion of the Ti3+O6 octahedron causes the variation of the linked LiO bond lengths and the corresponding LiO Coulomb energies, thus resulting in the diversity of Li ion migration barrier. In the lithiated LiTi2O4 state, the Li vacancy migration is also substantially affected by the JT distortion, while the influence of the JT distortion is much more complicated as more Ti3+ ions are created and the distribution of them is random. Our results are helpful to reveal the mechanism of Li ion migration in the spinel structures with JT distortions.
•JT distortion affects Li ion migration essentially in spinel TiO2.•The barrier of Li ion migration is related to the position of JT distortion.•The mechanism of influence of JT distortion on Li migration is clarified.