A method of forming a highly purified positive electrode active material is provided. A method of forming a positive electrode active material whose crystal structure is not easily broken even when charge and discharge are repeated is provided. The method of forming a positive electrode active material including lithium and a transition metal includes a first step of preparing a lithium source and a transition metal source and a second step of crushing and mixing the lithium source and the transition metal source to form a composite material. In the first step, a material with a purity of greater than or equal to 99.99% is prepared as the lithium source and a material with a purity of greater than or equal to 99.9% is prepared as the transition metal source. In the second step, crushing and mixing are performed using dehydrated acetone.

An electromagnetic wave absorbing sheet includes a metallic base and an electromagnetic wave absorption film formed on the metallic base. The electromagnetic wave absorption film contains MTC-substituted ε—Fe.sub.2O.sub.3, black titanium oxide, a conductive filler, and a resin. The MTC-substituted ε—Fe.sub.2O.sub.3 is a crystal belonging to the same space group as an ε—Fe.sub.2O.sub.3 crystal and containing Ti, Co, Fe, and at least one element selected from the group consisting of Ga, In, Al, and Rh. The proportion of the conductive filler to the electromagnetic wave absorption film is equal to or greater than 0.1% by volume and equal to or less than 10% by volume.

A method for producing a nickel cobalt complex hydroxide includes first crystallization of supplying a solution containing Ni, Co and Mn, a complex ion forming agent and a basic solution separately and simultaneously to one reaction vessel to obtain nickel cobalt complex hydroxide particles, and a second crystallization of, after the first crystallization, further supplying a solution containing nickel, cobalt, and manganese, a solution of a complex ion forming agent, a basic solution, and a solution containing said element M separately and simultaneously to the reaction vessel to crystallize a complex hydroxide particles containing nickel, cobalt, manganese and said element M on the nickel cobalt complex hydroxide particles crystallizing a complex hydroxide particles comprising Ni, Co, Mn and the element M on the nickel cobalt complex hydroxide particles.

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:

A1.sub.1-xA2.sub.xBO.sub.3-δ, 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 δ is an oxygen deficiency amount. The powder has a specific surface area of 20 m.sup.2/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.

Producing Co.sub.xFe.sub.100-x, where x is an integer from 20 to 95, nanoparticles by: (a) providing a first aqueous hydroxide solution; (b) preparing a second aqueous solution containing iron ions and cobalt ions; and (c) depositing measured volumes of the second aqueous solution into the first aqueous solution whereby coprecipitation yields CoFe alloy nanoparticles, wherein step (c) occurs in an essentially oxygen-free environment. The nanoparticles are annealed at ambient temperatures to yield soft nanoparticles with targeted particle size, saturation magnetization and coercivity. The chemical composition, crystal structure and homogeneity are controlled at the atomic level. The CoFe magnetic nanoparticles have M.sub.s of 200-235 emu/g, (H.sub.c) coercivity of 18 to 36 O.sub.e and size range of 5-40 nm. The high magnetic moment CoFe nanoparticles can be employed in drug delivery, superior contrast agents for highly sensitive magnetic resonance imaging, magnetic immunoassay, magnetic labeling, waste water treatment, and magnetic separation.

There are provided processes for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum, the process comprising: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum with lithium hydroxide, sodium hydroxide and/or potassium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate to an electromembrane process for converting the lithium sulfate, sodium sulfate and/or potassium sulfate into lithium hydroxide, sodium hydroxide and/or potassium hydroxide respectively; reusing the sodium hydroxide obtained by the electromembrane process for reacting with the metal sulfate; and reusing the lithium hydroxide obtained by the electromembrane process for reacting with the metal sulfate and/or with the metal hydroxide.

A method and device of removing and recycling metals from a mixing acid solution, includes adsorbing a mixing acid solution with a pH value of −1 to 4 and a cobalt ion concentration of 100 to 1,000 mg/L by at least two cation resins in series setting to the cobalt ion concentration in the mixing acid solution is less than 10 mg/L, and then adjusting the pH value of the mixing acid solution after adsorption to meet a discharge standard, wherein the particle size of the at least two cation resins in series setting is 150˜1,200 μm. After the cation resins are saturated by adsorption, regenerating the cation resins by sulfuric acid to form a cobalt sulfate solution, and then electrolytically treating the cobalt sulfate solution to obtain electrolytic cobalt and sulfuric acid electrolyte. The operation process is simple without complicated equipment, and it can effectively recycle metals from mixing acid solutions. The cationic resin and sulfuric acid solution can also be reused, so the method of the present invention has environmental and economic benefits.

A thermoelectric conversion material having a high dimensionless figure of merit ZT includes: a large number of polycrystalline grains which include a skutterudite-type crystal structure containing Yb, Co, and Sb; and an intergranular layer which is between the neighboring polycrystalline grains and includes crystals in which an atomic ratio of O to Yb is more than 0.4 and less than 1.5. A method for manufacturing a thermoelectric conversion material includes: a weighing step; a mixing step; a ribbon preparation step by rapidly cooling and solidifying a melt of the raw materials by using a rapid liquid cooling solidifying method; a first heat treatment step including heat treating in an inert atmosphere with an adjusted oxygen concentration; a second heat treatment step including heat treating in a reducing atmosphere; and manufacturing the thermoelectric conversion material by a pressure sintering step in an inert atmosphere.

A positive electrode active material precursor for a nonaqueous electrolyte secondary battery is provided that includes a nickel-cobalt-manganese carbonate composite represented by general formula Ni.sub.xCo.sub.yMn.sub.zM.sub.tCO.sub.3 (where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0≤t≤0.1, and M denotes at least one additional element selected from a group consisting of Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) and a hydrogen-containing functional group. The ratio H/Me of the amount of hydrogen H to the amount of metal components Me included in the positive electrode active material precursor is less than 1.60. The positive electrode active material further includes a secondary particle formed by a plurality of primary particles that have been aggregated.

A solid-state fuel battery comprises an anode, a cathode spaced from the anode, and a solid-state electrolyte disposed between the anode and the cathode. A material of the solid-state electrolyte is a hydrogen-containing transition metal oxide having a structural formula of ABO.sub.xH.sub.y, wherein A is one or more of alkaline earth metal elements and rare-earth metal elements, B is one or more of transition metal elements, x is a numeric value in a range of 1 to 3, and y is a numeric value in a range of 0 to 2.5. A method for making the solid-state electrolyte for the solid-state fuel battery is further provided in the present disclosure.