Alumina Doped Ni/YSZ Anode Materials for Solid Oxide Fuel Cells

The Al2O3-Ni-YSZ (Y2O2 stabilised ZrO2) anode materials with 0-6 wt% Al2O3 were prepared by tape casting method after being ball-milled for 48 h. The influence of Al2O3 content on flexural strength, electrical conductivity, open porosity, relative density and thermal expansion coefficient (TEC) of Al2O3-Ni-YSZ anode was investigated. The introduction of Al2O3 significantly enhances the flexural strength of Al2O3-Ni-YSZ anode. The flexural strengths of 430 and 299 MPa are achieved for the specimen containing 0.25 wt% Al2O3 before and after reduction, respectively, while the flexural strengths are 201 and 237 MPa for the Ni-YSZ samples. The density decreases with increasing Al2O3 content and the open porosity increases correspondingly, after being sintered at 1350 degrees C for 4 h. The electrical conductivity at ambient temperature does not fall off when Al2O3 content is less than 1 wt% but decreases rapidly when the content is above 3 wt% due to the formation of NiAl2O3 A maximum electrical conductivity of 1418 S cm(-1) is obtained in the sample containing 0.5 wt% Al2O3. The TEC of the samples decreases with the introduction of Al2O3 in the temperature range of 20-850 degrees C.