Regensburg 2019 – wissenschaftliches Programm
MM 22.5: Vortrag
Mittwoch, 3. April 2019, 11:15–11:30, H43
Description of bulk and surface polarons in oxide materials using DFT+U — •Matthias Kick, Cristina Grosu, Christoph Scheurer, Karsten Reuter, and Harald Oberhofer — Technische Universität München
Lithium titanium oxide Li4Ti5O12 (LTO) is an intriguing anode material promising particularly long lived batteries, due to its remarkable phase stability during (dis)charging of the cell. Moreover, its high intercalation potential also prevents the formation of Li dendrites. Unfortunately, the low intrinsic electronic conductivity of LTO still severely limits its use. An elegant way to improve on this drawback, is to introduce oxygen vacancies resulting in formation of Ti3+ centers. In our study we use Hubbard corrected density-functional theory (DFT+U) to show that this leads to the formation of polaronic states, which can again hamper electron conduction. In order to gauge the polaronic charge mobility we compare the relative stabilities of different polaron location patterns in bulk and surface LTO for a number of oxygen defects.