Exploration of fluoride glasses with faster fluoride-ion conduction

Abstract

Electrical conductivity measurements by ac methods were made of various fluoride glasses to explore glasses with faster fluoride-ion conduction. One of the measurements was made on ZrF 4BaF 2CsF glasses in which some of the fluoride-ions were substituted by the chloride, bromide, iodide and oxide ions. All of these substitutions resulted in a decrease in conductivity. The magnitude of the decrease was in proportion to the substituted fluoride-ion concentration, regardless of the substituent species. This may be explained by a blocking effect of the introduced anions of the fluoride-ion motion. Other electrical conductivity measurements were made of ternary and/or quaternary glasses of the ZrF 4 −, HfF 4 −, ZnF 2 −, ScF 3 −, MnF 2 − GaF 3 −, FeF 3 − and InF 3 −based fluoride systems. Remarkably high conductivities were observed in the InF 3 −, FeF 3 − and GaF 3 −based glasses containing appreciable amounts of PbF 2 as one of the glass constituents. Among these highly conductive glasses 35InF 3·30SnF 2·35PbF 2 glass exhibited extremely high conductivity, e.g., 6.3×10 −4 S cm −1 at 150 °C. This conductivity value is about 10 2 times the highest conductivity value thus far reported for fluorozirconate glasses and is higher than that of a crystalline material with fast fluoride-ion condition, β-PbF 2.