Abstract
• Ceria and NiO doping on A- and B-site was employed to modify SrFeO 3 perovskite. • Ferrite perovskite is explored as electrode material for a symmetrical SOFC. • Cells are coke-resistant over 300-hours at 0.5 V or 0.7 V under ethanol fuel. • High and stable performance was related to the dynamic consumption of C. • Exsolved CeO 2 and the Fe-Ni alloy are important for C-C cleavage and coke removal. A solid oxide fuel cell utilizing bio-fuels such as methanol and ethanol could provide a carbon–neutral electricity generation and facilitate its applications in transport or stationary power unit. Herein, Ce 4+ doping in SrFe 0.95 Ni 0.05 O 3 imparts FeNi 3 exsolution and CeO 2 precipitation in a reducing condition, contributing to the fuel reforming, C-C bond cleavage and coke consumption in the anode chamber. The ferrite perovskites are stable in ethanol/steam at 800 °C, whereas they are unstable in ethanol vapor with the high C fugacity inducing the formation of Fe 0 and carbides. However, the Ce 0.2 Sr 0.8 Fe 0.95 Ni 0.05 O 3 anode maintains mostly the perovskite and is free from coke after the 300 h’ operation under C 2 H 5 OH fuel at 0.5 V or 0.7 V because of the dynamic balance between the carbon deposition and consumption since an operation for 10 h shows a clear carbon deposition. A maximum power density of 0.58 W cm −2 and a polarization resistance of 0.21 Ω cm 2 at 800 °C can be obtained for the symmetrical solid oxide fuel cell with identical Ce 0.2 Sr 0.8 Fe 0.95 Ni 0.05 O 3 cathode and anode under an ethanol fuel. The results demonstrate that the reversible and stable SrFeO 3 with Ce/Ni co-doping has a bright prospect for alcohol fuel oxidation.
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