Dresden 2017 – wissenschaftliches Programm
MM 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 Köcher1,2, 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.