Method of producing positive electrode active material for nonaqueous electrolyte secondary battery

A method of producing a positive electrode active material for a nonaqueous electrolyte secondary battery, comprising:

• preparing a raw material mixture containing nickel-containing composite oxide particles and a lithium compound, wherein said nickel-containing composite oxide particles have a ratio 1D90/1D10 of a 90% particle size 1D90 to a 10% particle size 1D10 in volume-based cumulative particle size distribution of 3 or less, and wherein said raw material mixture has a ratio of a total number of moles of lithium to a total number of moles of metal elements contained in the composite oxide in a range of 1 to 3;
• subjecting the raw material mixture to a heat treatment to obtain a heat-treated material;
• dissociating sintered material from the heat-treated material to obtain a first dispersion;
• and
• bringing the first dispersion into contact with a liquid medium to obtain a second dispersion,
• wherein the heat treatment includes at least a heat treatment in a range of 850° C. to 1100° C.,
• wherein the positive electrode active material includes lithium-transition metal composite oxide particles, and
• wherein a molar ratio of nickel in a composition of the lithium-transition metal composite oxide to a total molar number of metals other than lithium is 0.6 or more and less than 0.95.