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MM: Fachverband Metall- und Materialphysik

MM 61: Functional materials IV: Batteries III

MM 61.1: Vortrag

Donnerstag, 10. März 2016, 15:45–16:00, H52

From micro- to mesoscale: The impact of occupational disorder on Li ion mobility in Li₄Ti₅O₁₂ battery materials — •Hendrik H. Heenen, Christoph Scheurer, and Karsten Reuter — Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Garching, Germany

Spinel-type lithium-titanium-oxide (Li₄Ti₅O₁₂) is an extraordinarily safe and long-living anode material employed in commercial lithium ion batteries. To complement experimental investigations, first-principles studies are often applied to gain microscopic insight into the underlying ion transport processes and the microscopic structure. This computationally demanding approach is however challenged by the treatment of the mixed occupancy of octrahedral sites by Li and Ti ions found in Li₄Ti₅O₁₂. The resulting vast configuration space is usually reduced to an idealized model, oversimplifying the investigated system. A numerically efficient, yet reliable, classical interatomic potential [1], allows for exploring the complex configuration space through extensive Monte-Carlo sampling and evaluating its electrochemical properties via molecular dynamics simulations. Our findings indicate a higher Li ion mobility with structural disorder, which is thermodynamically favored by high synthesis temperatures. We further assess the Markovian processes of the diffusion mechanism via a thorough microscopic analysis and elucidate the Li ion mobility in detail. This yields dynamic rates necessary for an extrapolation to kinetic Monte-Carlo simulations which pave the way for more quantitative predictions.

[1] M. Vijayakumar et al, J. Power Sources 196(4), 2211 (2011);