A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

Disclosed is a method for producing transition metal oxide fine particles having a size smaller than several micrometers (μm), and more preferably, having a size of several hundred nanometers (nm). To this end, the method for producing transition metal oxide fine particles of the present invention comprises dissolving a transition metal oxide in a strongly basic aqueous solution, and titrating same with a strongly acidic aqueous solution, thereby precipitating transition metal oxide fine particles.

A method of preparing a catalyst for oxidative dehydrogenation that includes coprecipitation and injecting inert gas or air at a specific time point to reduce the ratio of an inactive α-Fe.sub.2O.sub.3 crystal structure, thereby improving the activity of the catalyst. Also provided is a method of performing oxidative dehydrogenation using the catalyst. When oxidative dehydrogenation of butene is performed using the catalyst, side reaction may be reduced, and selectivity for butadiene may be improved, providing butadiene with high productivity.

The present disclosure provides methods for producing cathode materials for lithium ion batteries. Cathode materials that contain manganese are emphasized. Representative materials include Li.sub.xNi.sub.1-y-zMn.sub.yCo.sub.zO.sub.2 (NMC) (where x is in the range from 0.80 to 1.3, y is in the range from 0.01 to 0.5, and z is in the range from 0.01 to 0.5), Li.sub.xMn.sub.2O.sub.4(LM), and Li.sub.xNi.sub.1-yMn.sub.yO.sub.2 (LMN) (where x is in the range from 0.8 to 1.3 and y is in the range from 0.0 to 0.8). The process includes reactions of carboxylate precursors of nickel, manganese, and/or cobalt and lithiation with a lithium precursor. The carboxylate precursors are made from reactions of pure metals or metal compounds with carboxylic acids. The manganese precursor contains bivalent manganese and the process controls the oxidation state of manganese to avoid formation of higher oxidation states of manganese.

The present invention provides a method for the manufacture of transition metal oxide fine particles, the method comprising the steps of: heating a strong-alkaline aqueous solution while stirring same; adding to and dissolving in the heated strong-alkaline aqueous solution a transition metal oxide; adding a strong-acid aqueous solution to the strong alkaline aqueous solution in which the transition metal oxide is dissolved, while stirring same, thereby re-dissolving a solid generated at the interface between the strong-alkaline aqueous solution and the strong-acid aqueous solution; adjusting the pH of the mixed aqueous solution resulting from mixing the strong-alkaline aqueous solution and the strong acid aqueous solution, through adjustment of the adding rate and amount of the strong-acid aqueous solution, to precipitate transition metal oxide fine particles; and separating the transition metal oxide fine particles from the mixed aqueous solution and sequentially washing, drying, and thermally treating the separated transition metal oxide fine particles.

The present disclosure provides methods for producing cathode materials for lithium ion batteries. Cathode materials that contain manganese are emphasized. Representative materials include Li.sub.xNi.sub.1−y−zMn.sub.yCo.sub.zO.sub.2 (NMC) (where x is in the range from 0.80 to 1.3, y is in the range from 0.01 to 0.5, and z is in the range from 0.01 to 0.5), Li.sub.xMn.sub.2O.sub.4(LM), and Li.sub.xNi.sub.1−yMn.sub.yO.sub.2 (LMN) (where x is in the range from 0.8 to 1.3 and y is in the range from 0.0 to 0.8). The process includes reactions of carboxylate precursors of nickel, manganese, and/or cobalt and lithiation with a lithium precursor. The carboxylate precursors are made from reactions of pure metals or metal compounds with carboxylic acids. The manganese precursor contains bivalent manganese and the process controls the oxidation state of manganese to avoid formation of higher oxidation states of manganese.

The present invention provides a method for the manufacture of transition metal oxide fine particles, the method comprising the steps of: heating a strong-alkaline aqueous solution while stirring same; adding to and dissolving in the heated strong-alkaline aqueous solution a transition metal oxide; adding a strong-acid aqueous solution to the strong alkaline aqueous solution in which the transition metal oxide is dissolved, while stirring same, thereby re-dissolving a solid generated at the interface between the strong-alkaline aqueous solution and the strong-acid aqueous solution; adjusting the pH of the mixed aqueous solution resulting from mixing the strong-alkaline aqueous solution and the strong acid aqueous solution, through adjustment of the adding rate and amount of the strong-acid aqueous solution, to precipitate transition metal oxide fine particles; and separating the transition metal oxide fine particles from the mixed aqueous solution and sequentially washing, drying, and thermally treating the separated transition metal oxide fine particles.

A ceramic material, a varistor and methods for forming a ceramic material and a varistor are disclosed. In an embodiment, a ceramic material includes ZnO as a main component and additives selected from the group consisting of an Al.sup.3+-containing solution, a Ba.sup.2+-containing solution, and at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Sb, Co, Mn, Ni, Y, and Cr.

A metal bronze compound is provided. The metal bronze compound is a compound represented by formula (1) below. In formula (1), “A” represents at least one type of cation. “M” represents at least two types of ions selected from a transition metal and a metalloid. “x” represents the sum of the number of the at least one type of cation used as “A”. “y” represents the sum of the number of the at least two types of ions selected from the transition metal and the metalloid used as “M”. “z” represents the number of oxygen ion. The values of “x”, “y” and “z” balance the charge number of formula (1).
A.sub.xM.sub.yO.sub.z  (1)

Composite oxide fine particles are produced by sol-gel method under conditions in which coarse particles and aggregated particles are unlikely to be generated, and the composite oxide fine particles are further wet-filtered using a filter to remove the coarse particles and the aggregated particles. Then, a salt is added to a dispersion of the composite oxide fine particles to produce weak aggregates of the composite oxide fine particles in the dispersion. A solid content is separated from the dispersion of the composite oxide fine particles containing the aggregates, and then dried. The solid content is easily made finer because no firm aggregates are generated during the drying. That is, composite oxide fine particles containing no coarse particles and aggregated particles are obtained. Use of a known cracking means can further reduce the amount of coarse particles.