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

The Al 2 O 3 –Ni–YSZ (Y 2 O 3 stabilised ZrO 2 ) anode materials with 0–6 wt% Al 2 O 3 were prepared by tape casting method after being ball‐milled for 48 h. The influence of Al 2 O 3 content on flexural strength, electrical conductivity, open porosity, relative density and thermal expansion coefficient (TEC) of Al 2 O 3 –Ni–YSZ anode was investigated. The introduction of Al 2 O 3 significantly enhances the flexural strength of Al 2 O 3 –Ni–YSZ anode. The flexural strengths of 430 and 299 MPa are achieved for the specimen containing 0.25 wt% Al 2 O 3 before and after reduction, respectively, while the flexural strengths are 201 and 237 MPa for the Ni–YSZ samples. The density decreases with increasing Al 2 O 3 content and the open porosity increases correspondingly, after being sintered at 1350 °C for 4 h. The electrical conductivity at ambient temperature does not fall off when Al 2 O 3 content is less than 1 wt%, but decreases rapidly when the content is above 3 wt% due to the formation of NiAl 2 O 4 . A maximum electrical conductivity of 1418 S cm –1 is obtained in the sample containing 0.5 wt% Al 2 O 3 . The TEC of the samples decreases with the introduction of Al 2 O 3 in the temperature range of 20–850 °C.