Performance analysis of cobalt-based cathode materials for solid oxide fuel cell

摘要

The area specific resistance (ASR) characteristics of Ln1-xSrxM'1-yM"yO3-δ (Ln=Lanthanides, M' and M": transition metal such as Co and Fe), Sm0.5Sr1.5Co1-yNiyO4-δ and Sm0.5Sr1.5Co1-yFeyO4-δ oxides were investigated as cathode materials for intermediate temperature operating solid oxide fuel cell (IT-SOFC) application.As an effect of Sr substitution in A-site of perovskite, ASR of Nd0.5Sr0.5CoO3(NSC55) was 0.14 ft cm2 at 700℃. Sm0.5Sr0.5CoO3-δ (SSC55) on Ce0.9Gd0.1O2-δ(CGO91) and Ce0.8Sm0.2O2-δ(CSO82) showed the lowest ASR as 0.10 Ω cm2 and 0.085 Ω cm2 at 700℃ among various perovskite compositions in this study. ASR of B-site substituted Pr0.3Sr0.7Co0.3Fe0.7O3-δ (PSCF3737) in the Pr0.3Sr0.7Co1-yFeyO3-δ was about 0.13 Ω cm2 at 700℃. Comparing ASR of SSC55 as a perovskite structure with the value of Sm0.5Sr1.5Co1-yFeyO4-δ (y=0, 0.3, 0.5 and 0.7) as a spinel structure, the ASR of SSC55 was 0.085 ft cm2. However, the value of Sm0.5Sr1.5Co1-yFeyO4-δ(y=0,0.3,0.5 and 0.7) was much higher than SSC55 at 700℃. In XPS analyses, the atomic percentage values of PSC55 and PSC37 were 83.5, and 83.1%. However, the value of SrCoO3-δ was 50.2%. The results claim that more oxygen sites including oxygen vacancies on the surface of PSC55 and PSC37 exist than that of SrCoO3-δ.