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.

Provided is a novel compound which can be used for positive-electrode catalysts of metal-air batteries. The melilite-type complex oxide according to the present invention is represented by a general formula (BazSr1−z)2CoxFe2−2x(SiyGe1−y)1+xO7 (in the formula, 0≤x≤1, 0≤y≤1, and 0≤z≤1, excluding the case where x=1, y=1, and z=0, the case where x=1, y=1, and z=1, the case where x=1, y=0, and z=0, the case where x=1, y=0, and z=1, the case where x=0, y=0, and z=0, and the case where x=0, y=0, and z=1).

The present disclosure relates to a positive electrode material which includes a first positive electrode active material, and a second positive electrode active material in the form of a single particle, wherein an amount of lithium impurities on a surface of the second positive electrode active material is 0.14 wt % or less based on a total weight of the second positive electrode active material, and at least one of nickel, cobalt, and manganese included in the second positive electrode active material has a concentration gradient gradually changing from the center of the particle to a surface thereof, a method of preparing the positive electrode material, and a positive electrode for a lithium secondary battery and a lithium secondary battery which include the positive electrode material.

An object of the present invention is to provide a positive electrode active substance for a lithium secondary battery, the positive electrode active substance, when being used as a positive electrode active substance for a lithium secondary battery, being little in deterioration of cycle characteristics and being high in the energy density retention rate, even in repetition of charge and discharge at high voltages, and a lithium secondary battery little in deterioration of cycle characteristics and high in the energy density retention rate, even in repetition of charge and discharge at high voltages. The positive electrode active substance for a lithium secondary battery comprises a lithium cobalt-based composite oxide particle having a Ti-containing compound and an Mg-containing compound adhered on at least part of the particle surface.

The invention relates to a method for preparing a composite metal oxide hollow fibre. A certain stoichiometry of composite metal oxide raw material and a polymer binding agent are added to an organic solvent, and mixed mechanically to obtain an evenly dispersed spinning solution having a suitable viscosity. After defoaming treatment, the spinning solution is extruded through a spinneret and, after undergoing a certain dry spinning process, enters an external coagulation bath; during this period, a phase inversion process occurs and composite metal oxide hollow fibre blanks are formed. The blanks are immersed in the external coagulation bath and the organic solvent is displaced; after natural drying, the blanks undergo a heat treatment process; during this period, polymer burn off, in situ reaction, and in situ sintering processes occur to obtain the composite metal oxide hollow fibre.

Provided is a cobalt precursor for preparing a lithium cobalt oxide of a layered structure which is included in a positive electrode active material, wherein the cobalt precursor is cobalt oxyhydroxide (CoM′OOH) doped with, as dopants, magnesium (Mg) and M′ different from the magnesium.

A catalyst for decomposing an organic substance, the catalyst having a body which has a plurality of pores and the body 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, 1.001≤x≤1.1, 0.05≤z≤0.2, y+z=1, and w is a positive value that satisfies electrical neutrality. The average pore diameter of the plurality of pores is 49 nm to 260 nm and the pore volume of each of the plurality of pores is 0.08 cm.sup.3/g to 0.37 cm.sup.3/g.

The present invention relates to a composite of a cobalt-based perovskite material with a negative thermal expansion material, and a preparation method of the same, and a solid oxide fuel cell (SOFC) comprising the same, and belongs to the technical field of fuel cells. In the present invention, a negative thermal expansion material is introduced into a cobalt-based perovskite oxide to successfully prepare an SOFC cathode material with excellent electrochemical performance and low thermal expansivity. The composite electrode achieves prominent mechanical tolerance in SOFC, which can moderate a volume change during the whole calcination process and enable a smooth transition to a high-temperature stage. The composite electrode has a thermal expansion coefficient (TEC) only of 12.9×10.sup.−6 K.sup.−1, which is perfectly matched with that of an SDC electrolyte. In addition, the composite shows excellent oxygen reduction reaction (ORR) activity, high TEC, and extremely-excellent anti-CO.sub.2 poisoning performance.

A solid electrolyte having high electrical conductivity even in a low-temperature region is provided. A solid electrolyte containing a hexagonal perovskite-related compound, in which the compound is a compound represented by the following general formula (1), and an electrolyte layer and a battery using the solid electrolyte are disclosed. Ba.sub.7-αNb.sub.(4−x-y)Mo.sub.(1+x)M.sub.yO.sub.(20+z) (1), in the formula (1), M is a cation of at least one element; a represents a Ba deficiency amount and represents a value of 0 or more and 0.5 or less, x represents a value of −1.1 or more and 1.1 or less, y represents a value of 0 or more and 1.1 or less, and z represents an oxygen non-stoichiometry and represents a value of −2.0 or more and 2.0 or less, provided that in the formula (1), |x|+y≥0.01 is satisfied.

An electromagnetic wave absorbing particle has a composition, which is represented by Formula 1 of Sr.sub.1-xR.sub.xFe.sub.y-2zM.sub.2zO.sub.a and contains M-type hexaferrite as a main phase. In Formula 1, R is one or more substances selected from among Ba, Ca, and La, M is one or more substances selected from among Co, Ti, and Zr, 0<x≤0.8, 8≤y≤14, 0<z≤1.5, and a is equal to 19.