Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 31: Functional materials I: Supercapacitors and batteries I
MM 31.5: Vortrag
Mittwoch, 9. März 2016, 11:15–11:30, H53
DFT-supported study of ionic mobility in Li4Ti5O12 by solid-state NMR — •Simone Köcher1,2, Markus Schuderer2, 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 a detailed understanding of the ionic mobility in electrolyte materials. Notwithstanding, the experimental spectra are complex and their unambiguous interpretation has to rely on independent first-principles based calculations. For studies of the ionic charge carrier mobility in Li4Ti5O12 (LTO) by 7Li spin-alignment echo (SAE) NMR, we provide first-principles reference values for chemical shielding and quadrupolar coupling by density-functional theory (DFT) [1] calculations. The results imply that for a quantification of ion mobility two intrinsically different influences need to be considered. On the one hand, local mobility with fast motion on the experimental timescale partially averages the NMR parameters of interest. On the other hand, global mobility by slower motion between local domains is characterized by effective, residual parameters in NMR. Therefore, the conventional interpretation of 6,7Li chemical shifts and 7Li quadrupolar coupling in terms of static lithium occupancy might be incomplete.
[1] C. Bonhomme et al., Chem. Rev. 112, 5733 (2012).