Characterization of Sr/Ru co-doped ferrite based perovskite as a symmetrical electrode material for solid oxide fuel cells

The perovskite Sm0.9Sr0.1Fe0.9Ru0.1O3-delta (SSFR) is synthesized and investigated as a new type of symmetrical electrode material for solid oxide fuel cells (SOFCs). X-ray diffraction analysis indicates that SSFR exhibits an orthorhombic structure with a space group of Pnma (62). There are no significant changes in polarization resistance (R-p) after a series of experiments in hydrogen and oxygen atmospheres at 800 degrees C, implying that SSFR has a good redox stability. To get an insight into the rate-limiting steps of SSFR electrode, behavior of R-p, is investigated in different oxygen partial pressures (pO(2)). Generally, the relationship between Rp and pO(2) follows the equation R-p = k(pO(2))(-n) and different n values correspond to different rate-limiting steps. In this study, the n value of 0:5 is obtained for SSFR cathode at high temperature, relating to the diffusion of oxygen atom. In high pO(2), SSFR presents a p-type conducting behavior, with decreasing pO(2), a p-n transition occurs in the range 10(-17) to 10(-18) atm. Additionally, peak power density of the Sm0.2Ce0.8O1.9 (SDC, similar to 0.6 mm) electrolyte -supported symmetrical cell SSFRISDCISSFR achieves 119.69 mW cm(-2) at 800 degrees C using humidified hydrogen (similar to 3% H2O) as fuel. (C) 2017 Elsevier B.V. All rights reserved.