title: Mechanosynthesized nanocrystalline BaLiF(3): The impact of grain boundaries and structural disorder on ionic transport.
abstract: The mechanosynthesis of highly pure nanocrystalline BaLiF(3) is reported. The product with mean crystallite diameter of about 30 nm was prepared by joint high-energy ball-milling of the two binary fluorides LiF and BaF(2) at ambient temperature. Compared to coarse-grained BaLiF(3) with μm-sized crystallites, which is available via conventional solid-state synthesis at much higher temperatures, the mechanosynthesized product exhibits a drastic increase of ionic conductivity by several orders of magnitude. This is presumably due to structural disorder introduced during milling and to the presence of a large volume fraction of interfacial regions in the nanocrystalline form of BaLiF(3) providing fast diffusion pathways for the charge carriers. Starting from mechanosynthesized nanocrystalline BaLiF(3) it is possible to tune the transport parameters in a well defined way by subsequent annealing. Changes of the electrical response of mechanosynthesized BaLiF(3) during annealing are studied in situ by impedance spectroscopy. The results are compared with those of a structurally well-ordered single crystal which clearly shows extrinsic and intrinsic regions of ionic conduction.
authors: Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
authors: Andre
authors: A
authors: Düvel
authors: Martin
authors: M
authors: Wilkening
authors: Reinhard
authors: R
authors: Uecker
authors: Sebastian
authors: S
authors: Wegner
authors: Vladimir
authors: V
authors: Sepelák
authors: Paul
authors: P
authors: Heitjans
mesh_terms: D003460:Crystallization / Q000379:methods*; D007477:Ions / Q000737:chemistry; D018020:Lithium Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D036103:Nanotechnology / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; D018020:Lithium Compounds