A disordered rocksalt lithium metal oxide and oxyfluoride as in manganese-vanadium oxides and oxyfluorides well suited for use in high capacity lithium-ion battery electrodes such as those found in lithium-ion rechargeable batteries. A lithium metal oxide or oxyfluoride example is one having a general formula: Li.sub.xM′.sub.aM″.sub.bO.sub.2-yF.sub.y, with the lithium metal oxide or oxyfluoride having a cation-disordered rocksalt structure of one of (a) or (b), with (a) 1.09≤x≤1.35, 0.1≤a≤0.7, 0.1≤b≤0.7, and 0≤y≤0.7; M′ is a low valent transition metal and M″ is a high-valent transition metal; and (b) 1.1≤x≤1.33, 0.1≤a≤0.41, 0.39≤b≤0.67, and 0≤y≤0.3; M′ is Mn; and M″ is V or Mo. The oxides or oxyfluorides balance accessible Li capacity and transition metal capacity. An immediate application example is for high energy density Li-cathode battery materials, where the cathode energy is a key limiting factor to overall performance. The second structure (b) is optimized for maximal accessible Li capacity.

Magnetic powder includes: at least one epsilon-phase iron oxide-based compound selected from the group consisting of -Fe.sub.2O.sub.3 and a compound represented by Formula (1); and a surface treatment layer including a silane compound on at least a part of a surface. The magnetic powder has an average particle diameter of 8 nm to 20 nm. The content ratio of carbon atoms of the silane compound included in the surface treatment layer to iron atoms of the at least one epsilon-phase iron oxide-based compound selected from the group consisting of -Fe.sub.2O.sub.3 and the compound represented by Formula (1) is 0.05% to 0.5% in terms of the number of atoms. A manufacturing method thereof and applications thereof are also provided. In Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.
-A.sub.aFe.sub.2-aO.sub.3(1)

A sodium-based electrode active material and a secondary battery comprising the same are provided. The electrode active material is represented by the following Chemical Formula 1, and has an orthorhombic crystal system and a space group of Cmcm. [Chemical Formula 1] Na.sub.x[Mn.sub.1-y-zM.sup.1.sub.yM.sup.2.sub.z]O.sub.2-A.sub.. In Chemical Formula 1, x may be 0.5 to 0.8. M.sup.1 and M.sup.2 may be, regardless of each other, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nd, Mo, Tc, Ru, Rh, Pd, Pb, Ag, Cd, Al, Ga, In, Sn, or Bi. y may be from 0 to 0.25. z may be from 0 to 0.25. A may be N, O, F, or S, and may be 0 to 0.1.

Provided are: an Mn ferrite powder characterized by including a plurality of ferrite particles, having a volume-average particle diameter of 1-10 m, and having a 2.106 m volume-based cumulative distribution (sieved) of 0.1-50.0 vol %; and a resin composition characterized by including said powder and a resin material.

A carrier core material is represented by a composition formula M.sub.XFe.sub.3-XO.sub.4 (where M is at least one type of metal element selected from Mg, Mn, Ca, Ti, Cu, Zn and Ni, 0<X<1), in which part of M and/or Fe is substituted with Sr and formed of ferrite particles, and in the carrier core material, a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm, the amount of Sr eluted with pure water at a temperature of 25 C. is equal to or less than 50 ppm, an apparent density is equal to or more than 1.85 g/cm.sup.3 but equal to or less than 2.25 g/cm.sup.3 and magnetization .sub.1k when a magnetic field of 79.5810.sup.3 A/m (1000 oersteds) is applied is equal to or more than 63 Am.sup.2/kg but equal to or less than 75 Am.sup.2/kg.

A production method for a magnetic material, which is expressed by a chemical structure formula Fe(Al.sub.1-xMn.sub.x).sub.2O.sub.4, where 0<x<1, and exhibits ferromagnetism, includes: preparing a mixed aqueous solution by dissolving, in distilled water, Fe nitrate, Al nitrate, and an oxide including Mn, the Fe nitrate, the Al nitrate, and the oxide being parent materials; preparing a metal-citric acid complex by mixing citric acid and ethylene glycol with the mixed aqueous solution; obtaining a precursor by boiling the metal-citric acid complex to a gel and drying the gel; and obtaining the magnetic material by sintering the precursor.

The present invention provides the compound LiMn.sub.2--x-yNa.sub.xM.sub.yO.sub.4/Na.sub.1-zMnLi.sub.zM.sub.tO.sub.2/Na.sub.2CO.sub.3, to be used as a positive electrode for rechargeable lithium ion battery, where M is a metal or metalloid, 0.0x0.5; 0.0y0.5; 0.1z0.5; 0.0t0.3; as well as the method for producing it. The synthesis process includes disolving or mixing the precursor metals and then calcining them in air or controlled atmosphere in a temperature range between 250 C. and 1000 C., and for a time range of 0.5 h to 72 h to obtain the composite proposed with the interaction of its three present phases, presenting a high retention capacity during repeated loading/unloading cycles and excellent discharge capacity both at room temperature and up to 55 C.

A positive active material including: a core comprising a metal oxide, a non-metal oxide, or a combination thereof capable of intercalation and deintercalation of lithium ions or sodium ions; and a non-conductive carbonaceous film including oxygen on at least one portion of a surface of the core; a lithium battery including the positive active material; and a method of manufacturing the positive active material.

A sintered MnZn ferrite body containing main components comprising 53.30-53.80% by mol of Fe calculated as Fe.sub.2O.sub.3, 6.90-9.50% by mol Zn calculated as ZnO, and the balance of Mn calculated as MnO, and sub-components comprising 0.003-0.020 parts by mass of Si calculated as SiO.sub.2, more than 0 parts and 0.35 parts or less by mass of Ca calculated as CaCO.sub.3, 0.30-0.50 parts by mass of Co calculated as Co.sub.3O.sub.4, 0.03-0.10 parts by mass of Zr calculated as ZrO.sub.2, and 0-0.05 parts by mass of Ta calculated as Ta.sub.2O.sub.5, pre 100 parts by mass in total of the main components (calculated as the oxides), and having an average crystal grain size of 3 m or more and less than 8 m and a density of 4.65 g/cm.sup.3 or more.

A powder for dust cores includes an aggregate of soft magnetic particles, each of which includes a soft magnetic metal particle, and a ferrite film that covers a surface of the soft magnetic metal particle and includes ferrite crystal grains having a spinel structure. A diffraction peak derived from the ferrite crystal grains exists in a powder X-ray diffraction pattern. By a method for producing a powder for dust cores, a raw material powder that includes an aggregate of soft magnetic metal particles is prepared. Furthermore, many ferrite fine particles are formed on a surface of each of the soft magnetic metal particles of the raw material powder. Additionally, the ferrite fine particles are coarsely crystallized through heat treatment to form a ferrite film, which includes ferrite crystal grains having a spinel structure, on the surface of the each of the soft magnetic metal particles.