NMR spectroscopy – an all-round technique to study Li jump rates in solids?
Martin Wilkening
Institute for Chemistry and Technology of Materials, TU Graz
17:15 - 18:15 Tuesday 12 June 2012 TUG P2 Diffusion is one of the basic and ubiquitous phenomena in nature which is of crucial relevance for a large variety of processes and materials. In particular, fast ion conductors are needed to develop suitable electrolytes and electrode materials for all-solid-state lithium-ion batteries which are already part of our daily life.
Nuclear Magnetic Resonance (NMR) offers a large set of complementary techniques to study Li ion dynamics from an atomic-scale point of view. Taken together, the different techniques available cover a broad dynamic range, which, in the ideal case, exceeds more than ten decades. Whereas ultraslow Li jump processes with rates in the kHz range can be studied by analyzing the diffusion-induced decay of stimulated echoes, extremely fast Li+ dynamics, being characterized by residence times of the order of some nanoseconds, are accessible by spin-lattice relaxation measurements. The talk will give a brief overview of examples studied in our group during the last years. In particular, several fast ion conductors, such as garnet-type oxides and Li containing silicides, served as model systems to study both ion dynamics and dimensionality effects. The latter, in particular, can be probed by by taking advantage of frequency-dependent NMR spin-lattice relaxation measurements. Whenever possible the results were directly compared with those obtained from macroscopic techniques such as field gradient NMR and conductivity spectroscopy.
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