Ionic Conductivity of ZrF₄-BaF₂-MF_n Fluoride Glasses (M: The Group I∼V Metal Elements)

Abstract

Ionic conductivity measurements of ZrF₄-BaF₂-MF_n fluoride glasses were carried out to examine the relationship between glass-constituents and fluoride-ion conduction in fluorozirconate glasses. Twelve metal fluorides such as LiF, NaF, RbF, CsF, CaF₂, SrF₂, BaF₂, SbF₃, BiF₃, LaF₃, NdF₃, and HfF₄ were chosen as the MF_n components and four teen kinds of glasses in four compositions were submitted to the ionic conductivity measurements. The measurements were carried out in the temperature range from room temperature to glass transition temperature in argon atmosphere using the complex capacitance and complex impedance methods.
The ionic cond uctivity of glasses, represented by log σ=log σ₀-ΔE/2.303 kT, was nearly dependent only upon the activation energy. The polarizability of cation was found to he a dominant factor which governs activation energy. Thus, glasses with high mean polarizability of glass-constituting cations exhibited high ionic conductivity, and the ZrF₄BaF₂-CsF system was suggested to be a promising system that may provide a glass with higher fluoride-ion conduction.