Diffusion in Nanocrystalline Ion Conductors Studied by Solid State NMR and Impedance Spectroscopy

摘要

Materials with an average particle size of less than about 50 nm often show new or at least enhanced physical properties. In many cases nanocrystalline ionic conductors exhibit a high increase of cation, e. g. Li~+, or anion, e. g. F~-, diffusivity. In the present contribution we review recent studies on ion dynamics in nanocrystalline ion conductors, both single-phase systems and composites, being prepared by high-energy ball milling. These include, e.g., LiTaO_3, Li_2O:Al_2O_3, LiF:Al_2O_3, BaF_2, CaF_2, BaF_2:CaF_2 and (BaF_2:CaF_2):Al_2O_3. Dynamic properties were probed by ~7Li and/or ~(19)F NMR line shape and relaxation as well as ion conductivity measurements.