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Fast Ion Conducting Nanocrystalline Alkaline Earth Fluorides Simply Prepared by Mixing or Manual Shaking
Author(s) -
Scholz Gudrun,
Meyer Klas,
Düvel Andre,
Heitjans Paul,
Kemnitz Erhard
Publication year - 2013
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300083
Subject(s) - nanocrystalline material , alkaline earth metal , fluorine , fluoride , crystallite , inorganic chemistry , microcrystalline , chemistry , ion , materials science , metal , crystallography , organic chemistry
Simple mixing or shaking of alkaline earth hydroxides with ammonium fluoride results in nanocrystalline phase pure metal fluorides M F 2 ( M : Ca, Sr, Ba). The formation of the alkaline earth fluorides was investigated by varying the reaction conditions. Evidence was found that just the contact between the starting materials is sufficient for the reaction to take place. X‐ray diffraction, elemental analysis, 19 F MAS NMR spectroscopy, and measurements of DC conductivities were used to characterize the fluorides regarding properties like crystal structure, crystallite sizes, local fluorine coordination, and fluorine ion conductivity. The 19 F MAS NMR spectra of the phase pure fluorides prepared showed several signals, which were assigned to defects, impurities, or geometric distortions. The fluorides prepared by mixing or shaking revealed fluorine ion conductivities several orders of magnitude higher than observed for the respective microcrystalline alkaline earth fluorides. Therefore, the synthesis routine presented in this study may open a path to a very quick and simple synthesis of nanocrystalline fast fluorine ion conductors.