Abstract: A nickel cobalt manganese composite hydroxide with low impurity content and high reactivity when synthesizing a positive electrode active material, which can be used as a precursor of the positive electrode active material for non-aqueous electrolyte secondary batteries with low irreversible capacity, represented by a general formula: NixCoyMnzMt(OH)2+a (wherein x+y+z+t=1, 0.20?x?0.80, 0.10?y?0.50, 0.10?z?0.90, 0?t?0.10, 0?a?0.5, and M is at least one additive element selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, W), which includes: spherical secondary particles formed by aggregation of a plurality of plate-shaped primary particles, which have an average particle diameter of 3 ?m to 20 ?m, a sulfate radical content of 1.0 mass % or less, a chlorine content of 0.5 mass % or less, and a carbonate radical content of 1.0 mass % to 2.5 mass %.

Abstract: A method for producing a nickel-containing hydroxide is provided that includes a particle growth step of promoting growth of nickel-containing hydroxide particles by neutralization crystallization in an aqueous solution accommodated in an agitation tank. In the particle growth step, a volume fraction of a highly supersaturated region in the aqueous solution where the molar concentration of the nickel-containing hydroxide dissolved in the aqueous solution is greater than or equal to 1.7 mol/m3 is less than 0.624% of the aqueous solution.

Abstract: Provided is a positive electrode active material for nonaqueous electrolyte secondary batteries that suppresses the gelling of a positive electrode mixture material paste and has high weather resistance, a production method thereof, and the like. A method for producing a positive electrode active material for nonaqueous electrolyte secondary batteries includes cleaning a powder famed of a lithium-nickel composite oxide represented by a general formula LizNi1-x-yCoxMyO2 where 0?x?0.35; 0?y?0.10; 0.95?z?1.10; and M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al with an aqueous solution containing one or more lithium salts selected from water-soluble lithium salts other than lithium hydroxide and drying the cleaned powder.

Abstract: A nickel cobalt manganese composite hydroxide with low impurity content and high reactivity when synthesizing a positive electrode active material, which can be used as a precursor of the positive electrode active material for non-aqueous electrolyte secondary batteries with low irreversible capacity, represented by a general formula: NixCoyMnzMt(OH)2+a (wherein x+y+z+t=1, 0.20?x?0.80, 0.10?y?0.50, 0.10?z?0.90, 0?t?0.10, 0?a?0.5, and M is at least one additive element selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, W), which includes: spherical secondary particles formed by aggregation of a plurality of plate-shaped primary particles, which have an average particle diameter of 3 ?m to 20 ?m, a sulfate radical content of 1.0 mass % or less, a chlorine content of 0.5 mass % or less, and a carbonate radical content of 1.0 mass % to 2.5 mass %.