CATHODE ACTIVE MATERIAL PREPARATION METHOD

The present invention is an invention capable of reducing the usage amount of a rinsing solution, minimizing the surface degradation of a positive electrode active material, which occurs during a rinsing process, and effectively controlling residual lithium, and provides a method of preparing a positive electrode active material, which includes steps of: (A) preparing a lithium transition metal oxide; and (B) mixing the lithium transition metal oxide and a rinsing solution and performing rinsing and drying, wherein the rinsing solution includes one or more additives selected from among LiOH, NaOH, and KOH, the additive is included in an amount of 3,000 ppm to 18,000 ppm relative to the lithium transition metal oxide in the rinsing solution, and the rinsing solution has a pH of 12 or more.