| 摘要 |
PROBLEM TO BE SOLVED: To suppress the outflow of transition metal in manufacturing a nickel-cobalt composite hydroxide.SOLUTION: The method is for manufacturing a nickel-cobalt composite hydroxide which is expressed by the general formula, NiCoMnM(OH), where 0<x<1/2, 0≤y<1/2, 0≤z≤0.1, M is at least one element selected from a group consisting of Mg, Al, Ca, Ti, V, Cr, Zr, Nb, Mo and W, and makes a precursor of a positive-electrode active material of a nonaqueous electrolytic secondary battery. The method comprises: a crystallization step which includes preparing a reaction solution by mixing an aqueous solution mixture containing at least a nickel salt, a cobalt salt and a manganese salt, and an aqueous solution containing an ammonium ion supply source together while continuously supplying a caustic alkali aqueous solution, and continuously crystallizing nickel-cobalt composite hydroxide particles by keeping pH of the reaction solution within a fixed range; a pH control step which includes continuously supplying a caustic alkali aqueous solution to the nickel-cobalt composite hydroxide particle-containing reaction solution continuously discharged in the crystallization step, and raising pH of the reaction solution to 12.5 or higher on the basis of 25°C-liquid temperature to lower a transition metal ion density in the reaction solution; a solid-liquid separation step which includes separating the pH-controlled reaction solution containing nickel-cobalt composite hydroxide particles into solid and liquid, and then rinsing the nickel-cobalt composite hydroxide particles; and a drying step which includes drying the nickel-cobalt composite hydroxide particles thus rinsed by water. |
