Recycled positive electrode active material, method of producing the same, and secondary battery including the same

A method of producing a recycled positive electrode active material, comprising:

• injecting oxygen into a waste positive electrode having a positive electrode active material layer comprising 60 mol % or more of Ni on a current collector and subjecting the waste positive electrode to oxidation heat treatment to thermally decompose a binder and a conductive material in the positive electrode active material layer to separate the current collector from the positive electrode active material layer and recover a positive electrode active material from the positive electrode active material layer;
• first washing the recovered positive electrode active material;
• adding a lithium precursor to the first washed positive electrode active material and performing annealing;
• and
• second washing the annealed positive electrode active material.

A positive electrode active material, comprising:

• 60 mol % or more of Ni, and
• 305 mg/kg or less of fluorine (F),
• wherein the positive electrode active material has having a crystallite size of 139 nm or less, and
• wherein the positive electrode active material is one or more selected from the group consisting of a lithium nickel oxide (LNO)-based positive electrode active material, a nickel·cobalt·manganese (NCM)-based positive electrode active material, a nickel·cobalt·aluminum (NCA)-based positive electrode active material, and a nickel·cobalt·manganese·aluminum (NCMA)-based positive electrode active material.