Electrochemical analysis of Pr0.3Sr0.7CoxB(1-x)O3-delta (B = Fe, Mn, x=0, 0.3, 0.5, 0.7, and 1) as cathode materials for intermediate temperature SOFCs

Abstract

Selected Co-based perovskite cathode materials are investigated for use in intermediate-temperature solid oxide fuel cells (IT-SOFC). The complex perovskite-type Pr0.3Sr0.7CoxB(1-x)O3-delta (PSCB37X(1-X); B = Fe, Mn; x = 0, 0.3, 0.5, 0.7 and 1) is studied in this paper. These cathode compounds are synthesized using the glycine nitrate process (GNP) and characterized by powder X-ray diffraction (XRD), thermal expansion coefficient (TEC) measurements, and electrochemical impedance spectroscopy (EIS) using Ce0.9Gd0.1O2 (CG091) as an electrolyte. The area-specific resistances (ASR) of Pr0.3Sr0.7Co0.3Fe0.7O3-delta (PSCF3737) and Pr0.3Sr0.7Co0.7Mn0.3O3-delta (PSCM3773) are found to be 0.134 Omega.cm(2) and 0.174 Omega.cm(2), respectively, at 700 degrees C. The activation energy is calculated by fitting the slope of the ASR versus temperature. PSCF3737 and PSCM3773 exhibit the minimum activation energies found among the materials studied in this paper. The ASR values of PSCM3773 are shown to increase more sharply than those of PSCF3737 during thermal cycling over 1000 h of operation.