Abstract: A powder material for an air electrode in a solid oxide fuel cell, the powder material being a powder of a metal composite oxide having a perovskite crystal structure represented by: A11-xA2xBO3-?, where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and ? is an oxygen deficiency amount. The powder has a specific surface area of 20 m2/g or more, satisfies (Crystallite diameter/Specific surface area-based particle diameter)?0.3, and contains elements M in an amount of 300 ppm or less in terms of atoms, the elements M being other than the elements A1, A2 and B, and oxygen.

Abstract: The invention provides an air electrode material powder for solid oxide fuel cells, comprising particles of a perovskite composite oxide represented by the general formula ABO3, and comprising La and Sr as the A-site elements, and Co and Fe as the B-site elements.

Abstract: A method for producing a metal composite oxide, the method including steps of: preparing a slurry by mixing different kinds of metal compounds in a powder form, a dispersion medium, and a dispersant, and baking the different kinds of metal compounds after the dispersion medium in the slurry is removed. The slurry further includes a polyalkylene oxide having a viscosity average molecular weight of 150,000 or more. The slurry has a viscosity of 10 mPa·s to 2000 mPa·s, the viscosity being measured using a B-type viscometer under conditions of a temperature of 23° C. to 27° C. and a rotation rate of 60 rpm. According to the production method, a slurry in which different kinds metal compound powders are uniformly dispersed and a precipitate is unlikely to be formed can be obtained. Therefore, a metal composite oxide having a desired composition can be obtained.

Abstract: A powder for an air electrode in a solid oxide fuel cell, the powder consisting of: a metal composite oxide having a perovskite-type single phase crystal structure represented by A11-xA2xBO3-?, where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, 0<x<1, and the ? is an oxygen deficiency amount. When a cross section of a molded body obtained by compression molding the powder is observed at a magnification of 500 times, and a characteristic X-ray intensity of the element B is measured by an energy dispersive X-ray spectroscopy, the number of regions each having an intensity of 50% or higher of a maximum of the characteristic X-ray intensity of the element B and occupying 0.04% by area or more of the observation field of view is five or less.

Abstract: A powder material for an air electrode in a solid oxide fuel cell, the powder material being a powder of a metal composite oxide having a perovskite crystal structure represented by: A11-xA2xBO3-?, where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and ? is an oxygen deficiency amount. The powder has a specific surface area of 20 m2/g or more, satisfies (Crystallite diameter/Specific surface area-based particle diameter)?0.3, and contains elements M in an amount of 300 ppm or less in terms of atoms, the elements M being other than the elements A1, A2 and B, and oxygen.

Abstract: The invention provides an air electrode material powder for solid oxide fuel cells, comprising particles of a perovskite composite oxide represented by the general formula ABO3, and comprising La and Sr as the A-site elements, and Co and Fe as the B-site elements.

Abstract: The invention provides a method for producing a dispersion of microparticles of an inorganic oxide in an organic solvent having excellent transparency which comprises mixing an alcohol dispersion of microparticles of inorganic oxide selected from zirconia and titania with a silane coupling agent in the presence of an acid and stirring the resulting mixture to surface-treat the microparticles of the inorganic oxide at a temperature within a range from ?20 to 60° C.; and then replacing the alcohol by a lipophilic organic solvent.