Influence of synthesis methodology on the ionic transport properties of BaSnF<inf>4</inf>

The high performance fluoride ion conductor BaSnF4 has been prepared by a simple precipitation in addition to both solid state reaction and mechanochemical synthesis techniques. XRD results indicate that the material BaSnF4 obtained by all the methods crystallizes with the same tetragonal structure (P4/nmm). The crystallite size and morphology of the BaSnF4 particles determined by XRD and FE-SEM show a variation with respect to different methods of preparation. The transport properties of BaSnF4 have been investigated by impedance spectroscopy and the results show that the conductivity values are closely related to the crystallite size and micro-strain. The transport number measurement and NMR studies further confirm that the increase in conductivity is due to fluoride ions. The scaling result of complex impedance plots shows that the dynamical process occurring at various frequencies are independent of temperature. © 2011 Elsevier Ltd. All rights reserved.