Perovskite-type Nd_1-xBa_xCo_0.8Fe_0.2O_3-δ (0 ≤ x ≤ 0.7) cathodes for intermediate temperature solid oxide fuel cells

Perovskite-type metal oxides with a nominal chemical formula of Nd_1-xBa_xCo_0.8Fe_0.2O_3-δ (NBCF) (0 ≤ x ≤ 0.7) were prepared by solid-state synthesis method at 1300 °C in air. Powder X-ray diffraction showed that the x = 0.25 member is a single-phase perovskite-type Nd_0.75Ba_0.25Co_0.8Fe_0.2O_3-δ in the Pnma space group and all other members were found to be multiphase. All the investigated NBCF compositions show minor reactivity with the Sr and Mg-co-doped lanthanum gallate (LSGM) when sintered with 30 wt.% LSGM at 1050 °C but maintain their perovskite-type structure. 4-probe DC chronopotentiometry measurements were performed on the sintered sample pellets. The x = 0.4 member reaches a maximum conductivity of 1068 S/cm at 300 °C in air. Among the samples studied, the x = 0.55 member exhibits the lowest area specific polarization resistance (ASR) of 0.026 Ω cm² at 750 °C in air.