Synthesis and characterization of Mo-doped SrFeO_3-δ as cathode materials for solid oxide fuel cells

Journal Article · Thu Mar 01 04:00:00 EST 2012 · Journal of Power Sources

DOI:https://doi.org/10.1016/j.jpowsour.2011.11.021· OSTI ID:1383110

Xiao, Guoliang; Liu, Qiang; Wang, Siwei; Komvokis, Vasileios G.; Amiridis, Michael D.; Heyden, Andreas; Ma, Shuguo; Chen, Fanglin

This paper demonstrates the potential application of Mo-doped SrFeO_3-δ perovskites as new cathode materials for solid oxide fuel cells (SOFCs). SrFe_1-xMoxO_3-δ (x = 0, 0.05, 0.1, 0.2 and 0.25) perovskite materials have been synthesized by a microwave-assisted combustion method. By doping with Mo, the electrical conductivity of the doped SrFeO_3-δ in air is reduced with increasing amounts of Mo. At 800 °C, the conductivity drops from about 62 to 22 S cm^-1 when the doping level is increased to 25%. According to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR) results, a decrease in the concentration of charge carrier Fe⁴⁺ ions may account for the decrease in electrical conductivity. In contrast, the resistance to sintering and tolerance to reduction of SrFeO_3-δ are improved by Mo-doping. Additionally, the thermal expansion coefficient at 800 °C drops from 40.8 × 10^-6 K^-1 for SrFeO_3-δ to 25.7 × 10^-6 K^-1 for SrFe_0.8Mo_0.2O_3-δ and 20.9 × 10^-6 K^-1 for SrFe0.75Mo0.25O_3-δ. This significant decrease in the thermal expansion coefficient makes Mo-doped SrFeO_3-δ materials attractive as cathode candidates for SOFCs. Finally, a relatively low polarization resistance of 0.074 Ω cm2 is obtained for SrFe_0.8Mo_0.2O_3-δ at 800 °C in air.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Heterogeneous Functional Materials Center (HeteroFoaM)
• Sponsoring Organization: USDOE SC Office of Basic Energy Sciences (SC-22)
• DOE Contract Number: SC0001061
• OSTI ID: 1383110
• Journal Information: Journal of Power Sources, Journal Name: Journal of Power Sources Journal Issue: C Vol. 202; ISSN 0378-7753
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

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hydrogen and fuel cells
materials and chemistry by design
synthesis (novel materials)
synthesis (self-assembly)
synthesis (scalable processing)
mechanical behavior
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