A positive electrode active material for obtaining a lithium ion secondary battery, wherein capacity, electron conductivity, durability, and heat stability at the time of overcharge are improved, durability and heat stability being achieved at a high level, and including: a lithium nickel manganese composite oxide composed of secondary particles, in which a plurality of primary particles are flocculated, wherein the composite oxide is represented by a general formula (1): Li.sub.dNi.sub.1-a-b-cMn.sub.aM.sub.bTi.sub.cO.sub.2 (wherein, M is at least one kind of element selected from Co, W, Mo, V, Mg, Ca, Al, Cr, Zr and Ta, 0.05≤a≤0.60, 0≤b≤0.60, 0.02≤c≤0.08, 0.95≤d≤1.20), at least a part of titanium in the composite oxide is solid-solved in the primary particles, and, a lithium titanium compound exists on a surface of the positive electrode active material for the lithium ion secondary battery.

An object of the present invention is to provide a nanobubble-containing inorganic oxide fine particle dispersion having excellent concentration stability in a process used as an abrasive. The object is achieved by the nanobubble-containing inorganic oxide fine particle dispersion including: inorganic oxide fine particles having an average particle size of 1 to 500 nm and containing fine particles containing Ce; and nanobubbles having an average cell size of 50 to 500 nm and being at least one non-oxidizing gas selected from a group consisting of N.sub.2 and H.sub.2.

The present disclosure relates to a positive active material including a lithium transition metal oxide substituted with Na, W, Mg, Ti, and S, a method of preparing the same, and a lithium secondary battery having a positive electrode including the positive active material.

Provided are a ferrite powder that suppresses decreases in saturation magnetization and decreases in filler filling ratio and also suppresses inhibition of resin curing, and a method for producing the same. A ferrite powder composed of spherical ferrite particles, wherein the ferrite powder contains iron (Fe) 54.0-70.0 mass % and manganese (Mn) 3.5-18.5 mass %, has an average volume particle size of 2.0-20.0 μm, and has a carbon content of 0.100 mass % or lower.

A cerium-zirconium-aluminum-based composite material, a cGPF catalyst and a preparation method thereof are provided. The cerium-zirconium-aluminum-based composite material adopts a stepwise precipitation method, firstly preparing an aluminum-based pre-treated material, then coprecipitating the aluminum-based pre-treated material with zirconium and cerium sol, and finally roasting at high temperature to obtain the cerium-zirconium-aluminum-based composite material. The cerium-zirconium-aluminum-based composite material has better compactness and higher density, and when it is used in cGPF catalyst, it occupies a smaller volume of pores on the catalyst carrier, such that cGPF catalyst has lower back pressure and better ash accumulation resistance, which is beneficial to large-scale application of cGPF catalyst.

A positive electrode active material that can achieve high thermal stability at low cost is provided.

Provided is a positive electrode active material for a lithium ion secondary battery, the positive electrode active material containing a lithium-nickel-manganese composite oxide, in which metal elements constituting the lithium-nickel-manganese composite oxide include lithium (Li), nickel (Ni), manganese (Mn), cobalt (Co), titanium (Ti), niobium (Nb), and optionally zirconium (Zr), an amount of substance ratio of the elements is represented as Li:Ni:Mn:Co:Zr:Ti:Nb=a:b:c:d:e:f:g (provided that, 0.97≤a≤1.10, 0.80≤b≤0.88, 0.04≤c≤0.12, 0.04≤d≤0.10, 0≤e≤0.004, 0.003<f≤0.030, 0.001<g≤0.006, and b+c+d+e+f+g=1), and in the amount of substance ratio, (f+g)≤0.030 and f>g are satisfied.

A positive electrode active material includes lithium transition metal-containing composite oxide particles containing an additive element M1 and includes a coating layer formed of a metal composite oxide of Li and a metal element M2 on a part of a surface of the particles. The particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m.sup.2/g, a tap density of 1.0 to 2.0 g/cm.sup.3, and an oil absorption amount of 30 to 60 ml/100 g. For each of a plurality of primary particles having a primary particle size within a range of 0.1 to 1.0 μm among the primary particles, a coefficient of variation of the concentration of M1 is 1.5 or less, and the amount of M2 is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.

An object of the present invention is to provide a method for producing a pigment composition that can efficiently reduce the number of coarse particles in a pigment composition such as an aqueous pigment dispersion. The inventors of the present invention have achieved this object by a method of producing a pigment composition for ink, including a processing step of crushing or cracking a pigment component in a raw material composition containing the pigment component and a liquid medium using a rotor-stator processing machine 100.

A positive electrode active material for a non-aqueous electrolyte secondary battery according to an embodiment of the present disclosure is represented by a general formula of Li.sub.xNi.sub.yM.sub.1-yO.sub.2 (where M includes at least one metal element selected from Co and Mn, 0.1≤x≤1.2, 0.3<y<1), has a volumetric average particle size (D50) of 7 μm or more and 30 μm or less, and has an average surface roughness of 4%, or less.

Provided is a hollow particle, including silica, having a D.sub.SL of primary particles that satisfies the following expression (1), and having a breaking strength of 10 MPa or more: 1≤D.sub.SL≤1.5 . . . (1) where D.sub.SL=D.sub.75L/D.sub.25L, and D.sub.25L and D.sub.75L represent a 25th value and a 75th value, respectively, when long diameters of 100 randomly selected primary particles are measured in observation with a scanning electron microscope and sorted in order of increasing size.