Sr2CoMoO6 anode for solid oxide fuel cell running on H2 and CH4 fuels

The double perovskite Sr2CoMoO6−δ was investigated as a candidate anode for a solid oxide fuel cell (SOFC). Thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD) showed that the cation array is retained to 800 °C in H2 atmosphere with the introduction of a limited concentration of oxide–ion vacancies. Stoichiometric Sr2CoMoO6 has an antiferromagnetic Néel temperature TN ≈ 37 K, but after reduction in H2 at 800 °C for 10 h, long-range magnetic order appears to set in above 300 K. In H2, the electronic conductivity increases sharply with temperature in the interval 400 °C < T < 500 °C due to the onset of a loss of oxygen to make Sr2CoMoO6−δ a good mixed oxide–ion/electronic conductor (MIEC). With a 300-μm-thick La0.8Sr0.12Ga0.83Mg0.17O2.815 (LSGM) as oxide–ion electrolyte and SrCo0.8Fe0.2O3−δ as the cathode, the Sr2CoMoO6−δ anode gave a maximum power density of 1017 mW cm−2 in H2 and 634 mW cm−2 in wet CH4. A degradation of power in CH4 was observed, which could be attributed to coke build up observed by energy dispersive spectroscopy (EDS).

Figure optionsDownload as PowerPoint slideResearch highlights▶ Double perovskite Sr2CoMoO6 can be served as anode material for solid oxide fuel cell. ▶ Sr2CoMoO6 is a good mixed oxide–ion/electronic conductor. ▶ The Sr2CoMoO6 anode gives a maximum power density as high as 1017 mW cm−2 in H2 and 634 mW cm−2 in wet CH4. ▶ Conduction is dominated by Mo(V) small-polaron charge carriers, which depends on oxygen vacancies.