Microstructure evolution model of zirconia solid electrolyte based on AC impedance model analysis

Abstract

The effect of grain boundary on conductivity in multicomponent polycrystalline solid electrolyte has become a bottleneck for the development of high temperature solid electrolyte materials. The corresponding relationship between the microstructure and conductivity at high temperature is difficult to obtain based on the traditional methods of grain boundaries observation. In view of this, the variable temperature AC impedance characteristics of partially stabilized zirconia (PSZ) solid electrolyte material are investigated, and their fitting to AC impedance spectrum is analyzed. It is found that the fitting equivalent circuits varies with temperature increasing. By analyzing the physical meanings of different equivalent circuits, the microstructure evolution model of PSZ electrolyte material at elevated temperature is obtained. A microstructure model of 'short-range ordered ' with the structure of 'boundary bridge' is deduced after further analysis, which could provide the reference for improving the grain boundary conductivity in PSZ electrolyte materials.