Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 26: SYLI: Symposium Interfacial Challenges in Solid-State Li Ion Batteries - NMR studies

O 26.4: Vortrag

Dienstag, 21. März 2017, 11:00–11:15, IFW A

Combined DFT and solid-state NMR study of ionic mobility in Li₄Ti₅O₁₂ — •Simone Köcher^1,2, Andreas Garhammer², Hendrik Heenen², Magnus Graf¹, Josef Granwehr¹, Rüdiger-A. Eichel¹, Karsten Reuter², and Christoph Scheurer² — ¹IEK-9 - Fundamental Electrochemistry, Forschungszentrum Jülich, Jülich, Germany — ²Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Garching, Germany

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool to gain detailed understanding of the ionic mobility in battery materials. Notwithstanding, experimental spectra of novel high-capacitance electrodes such as the configurationally disordered defect spinel oxide Li₄Ti₅O₁₂ (LTO) are highly complex. Support by independent first-principles based calculations is indispensable to achieve an unambigious interpretation. We establish a corresponding framework for ⁷Li spin-alignment echo NMR studies of LTO by providing first-principles reference values for chemical shielding and quadrupolar coupling from density-functional theory calculations. A detailed comparison of experimental and theoretical data suggests that a local Li ion mobility faster than the experimental time resolution must have a considerable impact on the observed NMR quantities. We present first steps towards accounting for this local dynamics in the simulation of the autocorrelation function of the NMR experiment within a kinetic Monte Carlo model.