Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 18: Computational Materials Modelling - Phase Stability I
MM 18.4: Vortrag
Dienstag, 12. März 2013, 11:00–11:15, H24
The effect of partial occupancies on lithium ion diffusivity in lithium titanate oxides — •Benedikt Ziebarth — IAM, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany — Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstrasse 11, 79108 Freiburg, Germany
The effect of partial occupancies on lithium ion diffusivity in lithium titanate oxides Lithium titanate oxide (LTO) is a promising candidate as an anode material in future generations of lithium ion batteries. In this work, we investigate the diffusion barriers for lithium ions in two different crystal structures of LTO using the density functional theory. Our calculations show that the activation barriers vary between 0.30−0.48 eV for the spinel phase Li4Ti5O12 and between 0.20−0.51 eV in the lithiated rock salt phase Li7Ti5O12. The origins of the rather broad ranges of activation energies are related to different chemical environments of the diffusion channels due to partial occupancies of some sites in LTO. Our results reveal that determination of lithium diffusion constants in LTO cannot be carried out by using a single activation barrier. Instead, the local chemical environment of the diffusion paths must be considered to correctly capture the variety of activation barriers.