An object of the present invention is to provide zirconium oxide nanoparticles that have excellent dispersibility in a polar solvent and are capable of increasing a core concentration in a dispersion liquid. Zirconium oxide nanoparticles according to the present invention are coated with at least one compound selected from the group consisting of R.sup.1—COOH, (R.sup.1O).sub.3-n—P(O)—(OH).sub.n, (R.sup.1).sub.3-n—P(O)—(OH).sub.n, (R.sup.1O)—S(O)(O)—(OH), R.sup.1—S(O)(O)—(OH), and (R.sup.1).sub.4-m—Si(R.sup.4).sub.m, wherein R.sup.1 represents a group comprising a carbon atom and at least one element selected from the group consisting of an oxygen atom, a nitrogen atom, and a sulfur atom, and having the total number of carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms of 8 or less; R.sup.4 represents a halogen atom or —OR.sup.2, and R.sup.2 represents a hydrogen atom or an alkyl group; and n represents 1 or 2, and m represents an integer of 1 to 3.

A polycrystalline cubic boron nitride comprising 98.5% by volume or more of cubic boron nitride, wherein the cubic boron nitride has a dislocation density of more than 8×10.sup.15/m.sup.2, the polycrystalline cubic boron nitride comprises a plurality of crystal grains, and the plurality of crystal grains have a median diameter d50 of an equivalent circle diameter of 0.1 μm or more and 0.5 μm or less.

When a non-aqueous electrolyte secondary battery in which a positive electrode active material comprising a layered lithium-composite oxide is used for a positive electrode is subjected to charge/discharge under a prescribed condition, in a graph showing the relationship between voltage “V” with discharge during 5.sup.th cycle and value dQ/dV from differentiation of battery capacity “Q” with discharge during 5.sup.th cycle by voltage “V”, peak intensity ratio “r” represented by the equation: r=|Ic|/(|Ia|+|Ib|+|Ic|) satisfies 0<r≤0.25, in which |Ia| is absolute value dQ/dV for a peak top within a range of more than 3.9V to 4.4V or less, |Ib| is absolute value dQ/dV for a peak top within a range of more than 3.5V to 3.9V or less, and |Ic| is absolute value dQ/dV for a peak top within a range of 2.0V or more to 3.5V or less.

A method for producing a metal composite hydroxide, which includes a first crystallization process of supplying a first raw material aqueous and performing a crystallization reaction and a second crystallization process of supplying a second raw material aqueous solution containing a more amount of tungsten than the first raw material aqueous solution and performing a crystallization reaction to form a tungsten-concentrated layer and in which switching of reaction atmosphere from either atmosphere of a non-oxidizing atmosphere or an oxidizing atmosphere to the other atmosphere is performed two or more times in particle growth and the time for supplying the second raw material aqueous solution into the reaction tank in the non-oxidizing atmosphere is 50% or more with respect to the entire time for supplying the second raw material aqueous solution into the reaction tank.

The present application discloses an artificial graphite, a secondary battery, a preparation method and an apparatus. The artificial graphite includes secondary particles formed by agglomeration of primary particles, the artificial graphite having a volume average particle size Dv50, denoted as A, the artificial graphite through powder compaction under a pressure of 2000 kg having a volume average particle size Dv50, denoted as B, wherein A and B satisfies: B/A≥0.85. Using the artificial graphite provided by the present application can greatly reduce the cyclic expansion of the secondary battery.

A polysilicon rod wherein in an area whose distance from a center of a cross section of the polysilicon rod is within ⅔ of a radius and that excludes a seed core, average grain boundary characteristics have following features: a coincidence grain boundary ratio exceeds 20%, a grain boundary length exceeds 550 mm/mm.sup.2, and a random grain boundary length does not exceed 800 mm/mm.sup.2.

A method of forming an inorganic nano-material by thermally treating metal-infused organic polymers to remove the organics to leave an inorganic nano-material where the metal-infused organic polymer precursor may be formed by a polymer synthesis reaction of organic monomers with a metal-containing precursor and by combining a metal containing precursor with at least one organic monomer to obtain a mixture and initiating a polymerization reaction of the mixture to form a metal-infused organic polymer precursor.

The present invention relates to a composition based on yttrium oxide, on a cerium-based compound and on an organic compound and its use in the field of welding as stop-off product. The composition comprises, in an aqueous medium: yttrium oxide particles; particles of a cerium-based compound: which is cerium oxide; or which is prepared by the process consisting in causing a colloidal dispersion D, which is obtained by the neutralization of an aqueous cerium nitrate solution by a basic aqueous solution, to undergo heating; an organic compound chosen from the group formed by polyvinylpyrrolidone, polyvinyl alcohol, carboxymethyl cellulose and hydroxyethyl cellulose.

A lithium secondary battery includes a cathode including a cathode active material including a lithium-transition metal composite oxide particle having a crystal grain size of greater than 500 nm measured through X-ray diffraction (XRD) analysis, and an anode disposed to face the cathode. The present invention provides a lithium secondary battery having improved life-span characteristics while suppressing gas generation due to crack of the particles by controlling the crystal grain size of the lithium-transition metal composite oxide particles.

A cathode active material for a lithium secondary battery including a lithium-transition metal composite oxide particle is provided. A crystal grain size of the lithium-transition metal composite oxide particle measured by an XRD analysis is 250 nm or more, and an XRD peak intensity ratio of the lithium-transition metal composite oxide particle is 9.8% or less. A lithium secondary battery including the lithium-transition metal composite oxide particle and having improved life-span and rate capability is provided.