Effect of alumina on the properties of ceria and scandia co-doped zirconia for electrolyte-supported SOFC

The properties of ceria and scandia co-doped zirconia electrolytes with different alumina additions were investigated. Microstructure analysis revealed that alumina was an effective sintering aid for ceria and scandia co-doped zirconia. Small addition (<0.5 wt%) of alumina slightly increased the bulk conductivity. The grain boundary resistance was reduced significantly by alumina addition. Scavenging effect was observed at the grain boundary by element analysis resulting in about 20% increase in the specific grain boundary conductivity. Notable improvement in the flexural strength was measured after the addition of alumina. The sample with 0.5 wt% alumina, exhibiting enhanced grain boundary conductivity and flexural strength, was potential for the application in electrolyte-supported SOFC.