Solid oxide fuel cells (SOFCs) have the promise to improve energy efficiency and to provide society with a clean energy producing technology. The high temperature of operation (500−1000 °C) enables the solid oxide fuel cell to operate with existing fossil fuels and to be efficiently coupled with turbines to give very high efficiency conversion of fuels to electricity. Solid oxide fuel cells are complex electrochemical devices that contain three basic components, a porous anode, an electrolyte membrane, and a porous cathode. In this short review, a survey of the types and properties of materials that have been considered for each of these components is presented with an emphasis on the requirements for operation at intermediate temperature (500−800 °C). Some directions for future research are discussed.

Materials for Solid Oxide Fuel Cells

The electronic structure of transition metal oxides governs the catalysis of many central reactions for energy storage applications such as oxygen electrocatalysis. Here we exploit the versatility of the perovskite structure to search for oxide catalysts that are both active and stable. We report double perovskites (Ln₀.₅Ba₀.₅)CoO(₃-δ) (Ln=Pr, Sm, Gd and Ho) as a family of highly active catalysts for the oxygen evolution reaction upon water oxidation in alkaline solution. These double perovskites are stable unlike pseudocubic perovskites with comparable activities such as Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂O(₃-δ) which readily amorphize during the oxygen evolution reaction. The high activity and stability of these double perovskites can be explained by having the O p-band centre neither too close nor too far from the Fermi level, which is computed from ab initio studies.

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Double perovskites as a family of highly active catalysts for oxygen evolution in alkaline solution.

The literature on open-framework materials has shown numerous examples of porous solids with additional structural, chemical, or physical properties. These materials show promise for applications ranging from sensing, catalysis and separation to multifunctional materials. This critical review provides an up-to-date survey to this new generation of multifunctional open-framework solids. For this, a detailed revision of the different examples so far reported will be presented, classified into five different sections: magnetic, chiral, conducting, optical, and labile open-frameworks for sensing applications. (413 references.)

Old materials with new tricks: multifunctional open-framework materials.

Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin‐dependent electron scattering due to spin canting of the manganese oxide.

31p-S-4 Giant Magnetoresistance in Magnetic Manganese Oxide with Intrinsic Antiferromagnetic Spin Structure

Spintronics is a multidisciplinary field involving physics, chemistry, and engineering, and is a new research area for solid-state scientists. A variety of new materials must be found to satisfy different demands. The search for ferromagnetic semiconductors and stable half-metallic ferromagnets with Curie temperatures higher than room temperature remains a priority for solid-state chemistry. A general understanding of structure-property relationships is a necessary prerequisite for the design of new materials. In this Review, the most important developments in the field of spintronics are described from the point of view of materials science.

Spintronics: a challenge for materials science and solid-state chemistry.

Structural and Magnetic Studies of Ordered Oxygen-Deficient PerovskitesLnBaCo2O5+δ, Closely Related to the “112” Structure

Intercroissance de feuillets “perovskites lacunaires” et de feuillets type chlorure de sodium: Les oxydes La2−xA1+xCu2O6−x2 (A = Ca, Sr)

Oxygen defect K2NiF4-type oxides: The compounds La2−xSrxCuO4−x2+δ

Oxydes ternaires de cuivre a valence mixte de type K2NiF4 deficitaires en oxygene:Evolution progressive d'un etat semi-conducteur vers un etat semi-metallique des oxydes La2−xSrxCuO4−x2+δ

Ninh Nguyen

Papers

Structural and Magnetic Studies of Ordered Oxygen-Deficient PerovskitesLnBaCo2O5+δ, Closely Related to the “112” Structure

Intercroissance de feuillets “perovskites lacunaires” et de feuillets type chlorure de sodium: Les oxydes La2−xA1+xCu2O6−x2 (A = Ca, Sr)

Oxygen defect K2NiF4-type oxides: The compounds La2−xSrxCuO4−x2+δ

Oxydes ternaires de cuivre a valence mixte de type K2NiF4 deficitaires en oxygene:Evolution progressive d'un etat semi-conducteur vers un etat semi-metallique des oxydes La2−xSrxCuO4−x2+δ

Sr2Mn2O5, an oxygen-defect perovskite with Mn(III) in square pyramidal coordination