Nickel manganese composite hydroxide, method for producing same, positive electrode active material for nonaqueous electrolyte secondary batteries, method for producing said positive electrode active material, and nonaqueous electrolyte secondary battery

A nickel-manganese composite hydroxide comprising a secondary particle formed of a plurality of mutually flocculated primary particles and represented by General Formula (1):

• Nix1Mny1Mz1(OH)2+α (in the formula (1), 0.70≤x1≤0.95, 0.05≤y1≤0.30, x1+y1+z1=1.0, and 0≤α≤0.4 are satisfied;
• and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W), wherein
• the nickel-manganese composite hydroxide has a manganese-rich layer from a particle surface to a particle inner part of the secondary particle,
• the manganese-rich layer is represented by General Formula (2) below, and a thickness of the manganese-rich layer is at least 5% and up to 20% of a radius of the secondary particle:
• Nix2Mny2Mz2(OH)2+α General Formula (2):
• (in the formula (2), x2+z2=0 and y2=1 are satisfied or y2/(x2+z2)≥0.6 is satisfied;
• 0≤z2≤0.40, x2+y2+z2=1.0, and 0≤a≤0.4 are satisfied;
• and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W).