Method for producing positive active material precursor and positive active material for lithium secondary batteries, exhibiting concentration gradient, and positive active material precursor and positive active material for lithium secondary batteries, exhibiting concentration gradient, produced by same

A method for manufacturing a lithium secondary battery positive active material having a concentration gradient layer, the method comprising:

• inputting a chelating agent solution into a reactor;
• continuously inputting a core forming solution, a chelating agent solution, and an alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a core layer;
• continuously inputting a barrier layer forming solution, a chelating agent solution, and an alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a barrier layer;
• preparing a shell forming solution and continuously mixedly inputting a chelating agent solution, an alkaline solution, the core forming solution, and the shell forming solution into the reactor at the same time and obtaining a precipitate, which forms the concentration gradient layer where concentration of nickel-manganese-cobalt varies gradually and relatively, on a surface of the barrier layer;
• drying the precipitate;
• and
• thermally treating the dried precipitate.