Improvement of (La0.74Bi0.10Sr0.16)MnO3–Bi1.4Er0.6O3 composite cathodes for intermediate-temperature solid oxide fuel cells

Porous composite cathodes including (La0.74Bi0.10Sr0.16)MnO3−δ (LBSM) and Bi1.4Er0.6O3 (ESB) were fabricated and characterized using AC impedance spectroscopy. In our earlier work, the growth and aggregation of ESB particles were found in LBSM–ESB composite cathodes. In this study, therefore, two approaches were used to restrain the growth and aggregation of ESB particles. First, the sintering temperature of the composite cathode was reduced by introducing a sintering function layer, which caused a 22% reduction in the initial polarization resistance (R), but the cathode polarization resistance decreased at a rate of 2.15 × 10−4 Ω cm2 h−1 at 700 °C during a period of 100 h. Second, nano-sized Gd-doped ceria powder (CGO) was added to the composite cathode system. Stability improvement was achieved at 10 vol% CGO, and the degradation rate at 700 °C was 4.01 × 10−5 Ω cm2 h−1 during a period of 100 h.