METHOD OF MANUFACTURING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY

A method of manufacturing a positive electrode active material for a lithium-ion secondary battery includes a water-washing step of washing a lithium-nickel composite oxide containing Li, Ni, and an element M with water, and conducting a filtration to form a washed-cake, a mixing step of mixing, while heating, the washed-cake and a tungsten compound without lithium while heating to obtain a tungsten mixture, and a heat treatment step of heat-treating the tungsten mixture, wherein a water content of the washed-cake is 3.0% by mass or more and 10.0% by mass or less, a ratio of a number of tungsten atoms contained in the tungsten mixture to a total number of nickel and the element M atoms contained in the lithium-nickel composite oxide is 0.05 at. % or more and 3.00 at. % or less, and a temperature of the mixing step is 30° C. or higher and 70° C. or lower.