Method of producing nickel-cobalt composite hydroxide and method of producing positive electrode active material for non-aqueous electrolyte secondary battery

A method of producing a nickel-cobalt composite hydroxide, comprising:

• preparing a first solution containing nickel ions and cobalt ions;
• preparing a second solution containing tungsten ions and having a pH of 10 or more;
• preparing a third solution containing a complex ion-forming factor;
• preparing a liquid medium having a pH in a range of 10 to 13.5;
• supplying a portion of the first solution to the liquid medium to obtain a seed solution;
• supplying the first solution, the second solution, and the third solution separately and simultaneously to the seed solution to obtain a reacted solution, the reacted solution having a pH in a range of 10 to 13.5;
• and
• obtaining the nickel-cobalt composite hydroxide containing nickel, cobalt, and tungsten from the reacted solution.