Double Perovskite Anodo Materials

Chem. Mater. 2009, 21, 2319–2326

2319

Double-Perovskite Anode Materials Sr2MMoO6 (M ) Co, Ni) for
Solid Oxide Fuel Cells
Yun-Hui Huang,*,†,# Gan Liang,‡ Mark Croft,§,| Matti Lehtimaki,⊥ Maarit Karppinen,⊥ and
¨
John B. Goodenough†
Texas Materials Institute, ETC 9.102, The UniVersity of Texas at Austin, Austin, Texas 78712 Department
of Physics, Sam Houston State UniVersity, HuntsVille, Texas 77341, Department of Physics, Rutgers
UniVersity, Piscataway, New Jersey 08854, National Synchrotron Light Source, BrookhaVen National
Laboratory, Upton, New York 11973, Laboratory of Inorganic Chemistry, Department of Chemistry,
Helsinki UniVersity of Technology, FI-02015 TKK, Finland, and State Key Laboratory of Materials
Processing and Die and Mold Technology, School of Materials Science and Engineering, Huazhong
UniVersity of Science and Technology, Wuhan, Hubei 430074, China
ReceiVed December 16, 2008. ReVised Manuscript ReceiVed March 28, 2009

Double-perovskites Sr2MMoO6 (M ) Co, Ni) have been investigated as anode materials for a solid
oxide fuel cell. At room temperature, both Sr2CoMoO6 and Sr2NiMoO6 are tetragonal (I4/m). X-ray
absorption spectroscopy confirmed the presence of Co2+/Mo6+ and Ni2+/Mo6+ pairs in the oxygenstoichiometric compounds. The samples contain a limited concentration of oxygen vacancies in the reducing
atmospheres at an anode. Reoxidation is facile below 600 °C; they become antiferromagnetic at low
temperatures TN ) 37 and 80 K for M ) Co and Ni, respectively. As an anode with a 300 µm thick
La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte and SrFe0.2Co0.8O3-δ as a cathode, Sr2CoMoO6 exhibited maximum
power densities of 735 mW/cm2 in H2 and 527 mW/cm2 in wet CH4 at 800 °C; Sr2NiMoO6 shows a
notable power output only in dry CH4. The high performance of Sr2CoMoO6 in wet CH4 may be due to
its catalytic effect on steam reforming of methane, but some degradation of the structure that occurred
in CH4 obscures identification of the...