Nb-substituted PrBaCo2O5+δ as a cathode for solid oxide fuel cells: A systematic study of structural, electrical, and electrochemical properties

The as-prepared PrBaCo2−xNbxO5+δ with x = 0, 0.25, 0.50, 0.75, and 1.00 (PBCN) exhibit structural change from P4/mmm (x = 0) to I4/mmm (x = 1), whereas both phases are present for intermediate compositions. The analysis of electrochemical impedance spectroscopy (EIS) data shows that PBCN is characterized by relatively low polarization resistance. Between 300 and 800 °C, the electrical conductivity of PBCN, with x = 0.25, 0.50, lies above 100 S cm−1. If x = 0.75 or 1.00, the conductivity drops below 100 S cm−1. Our work suggests that the Nb-doped PBC exhibits excellent chemical compatibility with typical electrolyte material and good electrochemical performance, making it a promising cathode material for applications in IT-SOFCs.