A lithium cobalt-based positive electrode active material is provided. The lithium cobalt-based positive electrode active material includes a core portion including a lithium cobalt-based oxide represented by Formula 1 and a shell portion including a lithium cobalt-based oxide represented by Formula 2, wherein the lithium cobalt-based positive electrode active material includes 2500 ppm or more, preferably 3000 ppm or more of a doping element M based on the total weight of the positive electrode active material. An inflection point does not appear in a voltage profile measured during charging/discharging a secondary battery including the lithium cobalt-based positive electrode active material.

In an aspect, a ferrite composition comprises a Ru—Co.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(M′Ru).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M′ is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is −4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the Ru—Co.sub.2Z ferrite.

The perovskite compound according to the invention has a cubic perovskite structure, has high catalytic activity in oxygen reduction and evolution reactions, and has excellent durability, and thus, can be used as a catalyst of electrochemical devices, particularly as a fuel cell catalyst.

This thermoelectric conversion module is formed by electrically connecting, by a conductive member, one end of an n-type thermoelectric conversion element having a negative Seebeck coefficient and having a half-Heusler structure to one end of a p-type thermoelectric conversion element containing an oxide having a positive Seebeck coefficient at a temperature of 25° C. or higher. The conductive member is connected to the n-type thermoelectric conversion element and the p-type thermoelectric conversion element through a connection layer containing a conductive metal comprising silver, and the connection layer is characterized by further containing an oxide to reduce the bond resistance between the n-type thermoelectric conversion element and/or the p-type thermoelectric conversion element.

A supported catalyst for decomposing an organic substance that includes a support and a catalyst particle supported on the support. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni and Fe, y+z=1, x≥0.995, z≤0.4, and w is a positive value satisfying electrical neutrality. A film thickness of a catalyst-supporting film supported on the support and containing the catalyst particle is 5 μm or more, or a supported amount as determined by normalizing a mass of the catalyst particle supported on the support by a volume of the support is 45 g/L or more.

A solid ionic conducting material for use in an electrochemical device comprises an oxyhydroxide or hydrated oxide derived from of an oxide with a perovskite, Brownmillerite, layered oxide, and/or K.sub.4CdCl.sub.6 structure, the elemental composition of the initial oxide being selected to provide suitable conduction properties for the derived anhydrous or hydrated oxyhydroxide or hydrated oxide. A method of making such a solid ionic conducting material, including treatment with water, and an electrochemical device incorporating such a solid ionic conducting material (optionally as an electrolyte) are also disclosed.

Nanowire synthesis and one dimensional nanowire synthesis of titanates and cobaltates. Exemplary titanates and cobaltates that are fabricated and discussed include, without limitation, strontium titanate (SrTiO.sub.3), barium titanate (BaTiO.sub.3), lead titanate (PbTiO.sub.3), calcium cobaltate (Ca.sub.3Co.sub.4O.sub.9) and sodium cobaltate (NaCo.sub.2O.sub.4).

Provided are a positive active material, a positive electrode including the same, and a lithium secondary battery including the positive electrode. The positive active material includes lithium cobalt oxide containing a metal element, and the lithium cobalt oxide containing a metal element has a ratio of a peak intensity of the O3 phase to a peak intensity of the H1-3 phase, I.sub.O3/I.sub.H1-3, that is greater than 1 in a X-ray diffraction (XRD) analysis spectrum using Cu-Kα radiation. Accordingly, a lithium secondary battery including the positive active material may have improved lifespan characteristics even at a high voltage.

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

[Object] A cobalt ferrite magnetic powder includes magnetic particles that have a uniaxial crystal magnetic anisotropy and contain cobalt ferrite. A peak top 2θ of a (3, 1, 1) plane determined by powder X-ray diffractometry using a CoKα ray is 41.3° or more and 41.5° or less. Some Cos contained in the magnetic particles are substituted with at least one selected from the group consisting of Zn, Ge, and a transition metal element other than Fe.