(Digital Presentation) Improved Densification of Proton Conducting BaCe0.5Zr0.3Y0.2O3-δ by Impurity Addition

Abstract

BaCe0.5Zr0.3Y0.2O3-δ (BCZY) electrolyte is known to be a high proton conducting electrolyte for proton-solid oxide electrolyzer cell (P-SOEC) applications. There are some advantages such as (1) Reduce Cr evaporation and mitigate materials degradation, (2)Use of lower cost metals, alloys and coatings, (3) Ease of gas sealing, (4) Reduced cost of hydrogen production by using proton conducting electrolyte. To become a desired solid electrolyte with >95% relative density, a typical BCZY electrolyte needs to be sintered at temperatures greater than 1400°C. A better sintering approach was developed in this study.With slight modification on sintering conditions, dense BaCe0.5Zr0.3Y0.2O3-δ electrolyte was obtained at a temperature as low as 1200°C. Without any modification, BCZY reached 90% relative density only when sintered at 1250°C. With proper impurity addition, BCZY may reach 97% relative density under the same conditions. From analysis, it is suggested that the densification of BCZY is promoted due to impurity induced liquid-phase sintering mechanism. In addition, the conductivity of highly densified BCZY reached 5.86×10-3 S/cm at 700°C. The crystal structure and microstructure of sintered BCZY was also characterized using XRD and field-emission SEM.