Method of mixing cathode active material

A method of mixing a cathode active material in a process of manufacturing a cathode of a lithium secondary battery, comprising:

• a preparation step of preparing a lithium compound removal solution in which PAA (polyacrylic acid) is mixed with a solvent, wherein in the preparation step, the lithium compound is LiOH;
• a removal step of reacting the lithium compound removal solution with the cathode active material, on a surface of which the lithium compound is present, thus removing the lithium compound present on the surface of the cathode active material;
• a mixing step of mixing the cathode active material, which is mixed with the lithium compound removal solution, with a conductive material and a binder;
• and
• between the removal step and the mixing step, a reaction maintenance step of maintaining a reaction for 20 minutes or more so that the LiOH present in the cathode active material is reacted with the PAA to generate Li-PAA.