Characterization of B‐Site Niobium‐Doped Pr 0.4 Sr 0.6 (Co 0.3 Fe 0.6 ) 1‐x Nb x O 3‐δ (x=0, 0.05, 0.1, 0.2) Perovskites as Cathode Materials for Solid Oxide Fuel Cells

Perovskite materials of Pr 0.4 Sr 0.6 (Co 0.3 Fe 0.6 ) 1‐x Nb x O 3‐δ (PSCFN x , x=0, 0.05, 0.1, 0.2) were firstly synthesized as the cathode materials for solid oxide fuel cells (SOFCs) by doping niobium(Nb) at the B site of Pr 0.4 Sr 0.6 Co 0.3 Fe 0.6 O 3‐δ using a solid state reaction method. The effect of Nb doping amount on the lattice structure, oxygen desorption and electrochemical properties of PSCFN x at different calcination temperatures were investigated. It is found that this material family had perfectly cubic structure based on the Pm‐3 m space group whose lattice size increased with x. These materials were thermally stable after calcination and showed desirable chemical compatibility with electrolyte in the condition of calcination at 1250 °C for 8 h under an air atmosphere. The optimum x value of 0.1 was found for the PSCFN x cathode materials, which had the minimum polarization resistance value of 0.018 Ωcm 2 at 900 °C. As a result, the single cell with the PSCFN 0.1 cathode delivered a power density of 0.731 Wcm −2 at 900 °C with humidified H 2 (∼3% H 2 O) as the fuel and ambient air as the oxidant. It indicates that PSCFN 0.1 should be a promising cathode material for the SOFCs.