Characterization of B‐Site Niobium‐Doped Pr_0.4Sr_0.6 (Co_0.3Fe_0.6)_1‐xNb_xO_3‐δ (x=0, 0.05, 0.1, 0.2) Perovskites as Cathode Materials for Solid Oxide Fuel Cells

Abstract

Perovskite materials of Pr0.4Sr0.6(Co0.3Fe0.6)1‐xNbxO3‐δ (PSCFNx, 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 Pr0.4Sr0.6Co0.3Fe0.6O3‐δ using a solid state reaction method. The effect of Nb doping amount on the lattice structure, oxygen desorption and electrochemical properties of PSCFNx 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 PSCFNx cathode materials, which had the minimum polarization resistance value of 0.018 Ωcm2 at 900 °C. As a result, the single cell with the PSCFN0.1 cathode delivered a power density of 0.731 Wcm−2 at 900 °C with humidified H2 (∼3% H2O) as the fuel and ambient air as the oxidant. It indicates that PSCFN0.1 should be a promising cathode material for the SOFCs.

Highly Improved Electrochemical Performance of a Fe‐based Cathode by Introducing A‐site Cationic Deficiencies

“…The additional peaks at 714.8-720.8 eV are related to the satellite peaks. [25] At the same time, the ratio of Fe 4 + /Fe 3 + peak areas of SBF and SB0.45F oxide is displayed in Table 1. It could be noted that the Bi-site deficient SB0.45F oxide shows a larger Fe 4 + /Fe 3 + peak area ratio than SBF.…”