Nickel-cobalt composite hydroxide and process for manufacturing same

A process for manufacturing a nickel-cobalt composite hydroxide, the nickel-cobalt composite hydroxide being represented by a general formula:

• Ni1-x-yCoxMnyMz(OH)2 (where, 0.05≦x≦0.95, 0≦y≦0.55, 0≦z≦0.1, x+y+z<1, and M is at least one metal element selected from Al, Mg, Ti, Fe, Cu, Zn, and Ga) and for use as a positive electrode active material for nonaqueous-electrolyte secondary batteries, the process comprising:
• a seed particle formation step wherein, while a reaction solution which comprises a mixed solution containing metal compounds including metals constituting the general formula and an ammonia solution containing an ammonium ion supply source is agitated at a discharge head of an impeller of from 50 to 100 m2/s2, a concentration of nickel ions in the reaction solution is maintained within a range from 0.1 to 5 ppm by mass, whereby seed particles are formed;
• and
• a seed particle growth step wherein a solution for seed particle growth which comprises the reaction solution containing the seed particles, a mixed solution containing metal compounds including metals constituting the formula, and an ammonium solution containing an ammonium ion supply source is agitated with a concentration of nickel ions being maintained in a range from 5 to 300 ppm by mass and higher than the concentration of nickel ions in the seed particle formation step, whereby the seed particles are grown up to obtain nickel-cobalt composite hydroxide particles.