Electrochemical Performance of Cobalt‐free Nd0.5Ba0.5Fe1–xNixO3–δ Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

Abstract A new series of cobalt‐free perovskite‐type oxides, Nd 0.5 Ba 0.5 Fe 1–x Ni x O 3– δ (0 ≤ x ≤ 0.15), have been prepared by a citric acid‐nitrate process and investigated as cathode materials for proton conducting intermediate temperature solid oxide fuel cells (IT‐SOFCs). The conductivity of the oxides was measured at 300–800 °C in air. It is discovered that partial substitution of Ni for Fe‐sites in Nd 0.5 Ba 0.5 Fe 1–x Ni x O 3– δ obviously enhances the conductivity of the oxides. Among the series of oxides, the Nd 0.5 Ba 0.5 Fe 0.9 Ni 0.1 O 3– δ (NBFNi10) exhibits the highest conductivity of 140 S cm −1 in air at 550 °C. A single H 2 /air fuel cell with proton‐conducting BaZr 0.1 Ce 0.7 Y 0.2 O 3– δ (BZCY) electrolyte membrane (ca. 40 μm thickness) and NBFNi10‐BZCY composite cathode and NiO‐BZCY composite anode was fabricated and tested at 600–700 °C. The peak power density and the interfacial polarization resistance ( R p ) of the cell are 490 mW cm −2 and 0.15 Ω cm 2 at 700 °C, respectively. The experimental results indicate that NBFNi10 is a promising cathode material for the proton‐conducting IT‐SOFCs.