Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 14: Transport I: Diffusion
MM 14.6: Vortrag
Montag, 16. März 2015, 17:15–17:30, H 0107
Multiscale modeling approach to occupationally disordered materials: Ion diffusion in Lithium-Titanium-Oxide battery materials — •Hendrik H. Heenen, Saskia Stegmaier, Christoph Scheurer, and Karsten Reuter — Technische Universität München
Lithium-titanium-oxide (LTO) materials have caught a lot of attention as an alternative anode material for lithium ion batteries as they offer high cycling stability, safe operation at high working potentials and a fast charge-discharge behavior. Aiming to link this macroscopic electrochemical performance to the underlying atomic-scale processes, first-principles studies generally offer a unique opportunity to understand the Li ion diffusion and material’s structure. In particular for the spinel-type Li4Ti5O12 LTO they are, however, challenged by the mixed occupancy of octahedral sites by Li and Ti ions [1]. This allows for a high degree of occupational disorder that can not be appropriately sampled within supercell sizes accessible to present-day first-principles calculations. We address this challenge with a multiscale approach involving interatomic potentials that are parametrized and validated by density-functional theory. This allows to thoroughly sample the configuration space of Li4Ti5O12 and perform an analysis of the variety of diffusion pathways. Particular focus is placed on the dependency of the average and local Li ion mobility on the thermodynamically accessible configuration space.
[1] B. Ziebarth et al, Phys. Rev. B 89, 174301 (2014).