Polarization resistance and composite cathode of Ce doped SrMnO sub(3) system for intermediate temperature solid oxide fuel cells

• Published in: Solid state ionics 2014-07, Vol.260, p.60-64
• Main Authors: Ryu, Jiseung, O'Hayre, Ryan, Lee, Heesoo
• Format: Article
• Language: English
• Subjects: Binding; Cathodes; Cathodic polarization; Citrates; Lattice vacancies; Lattices; Polarization; Solid oxide fuel cells
• ISSN: 0167-2738
• DOI: 10.1016/j.ssi.2014.03.017

Sr sub(1-x)Ce sub(x)MnO sub(3) (SCM, x = 0.1, 0.2, 0.3) materials synthesized through the EDTA citrate complexing process show a single perovskite structure, and the refined lattice volume increases with the concentration of Ce ions. An increase in the Mn super(3+) concentration with increasing Ce doping was confirmed by Mn L sub(3,2)-edge analysis, and we observe an expansion of the lattice volume due to the larger ionic radii of Mn super(3+), as compared to that of Mn super(4+). The change in the O K-edge caused by increasing Ce content presented an increase in the binding force of the oxygen ions. We hypothesize that the decrease in oxygen vacancy concentration caused by the increase in the oxygen binding force impedes the oxygen ion transfer process, which causes an increase in the polarization resistance (R sub(p)) with the increasing concentration of Ce ions in the SCM system. The R sub(p) value of Sr sub(1-x)Ce sub(x)MnO sub(3)/Sm sub(0.2)Ce sub(0.8)C sub(2) (SCM/SDC) composite cathodes was lower than that of pure SCM cathodes at the measured temperature, especially the R sub(p) value of SCM10/SDC (0.88 cm super(2) at 800 parallel C), which is about seven times lower than that of SCM10 at the same temperature.