Influence of anode pore forming additives on the densification of supported BaCe_0.7Ta_0.1Y_0.2O_3-δ electrolyte membranes based on a solid state reaction

We describe a solid state reaction for the preparation of both NiO-BaCe_0.7Ta_0.1Y_0.2O_3-δ anode substrates and BaCe_0.7Ta_0.1Y_0.2O_3-δ (BCTY10) electrolyte membranes on porous NiO-BCTY10 anode substrates. The amounts of the pore forming additive in the substrates showed a significant influence on the densification of the BCTY10 membranes. After sintering at 1450 °C for 5 h, the BCTY10 membrane on a NiO-BCTY10 anode containing 30 wt.% starch achieved a high density and showed adequate chemical stability against H₂O and CO₂. The chemical stability of BCTY10 was even better than that of BaCe_0.7Zr_0.1Y_0.2O_3-δ. With a mixture of BaCe_0.7Zr_0.1Y_0.2O_3-δ (BZCY7) and La_0.7Sr_0.3FeO_3-δ (LSF) as a cathode, a single fuel cell with 12 μm thick BCTY10 electrolyte generated maximum power densities of 142, 93, 29 mW/cm² at 700, 600 and 500 °C, respectively. The electrolyte resistance and interfacial polarization resistance of the cell under open circuit conditions were also investigated.