Method for reusing active material using positive electrode scrap

A method for reusing a positive electrode active material, comprising:

• (a) thermally treating positive electrode scrap comprising a lithium cobalt oxide positive electrode active material layer on a current collector in air at 300 to 650° C. for 1 hour or less for thermal decomposition of a binder and a conductive material in the active material layer, to separate the current collector from the active material layer, and collecting an active material in the active material layer;
• (b) washing the active material collected from the step (a) for 10 min or less using a lithium precursor aqueous solution and drying, wherein the lithium precursor aqueous solution is basic in an aqueous solution and contains a lithium precursor in an amount of more than 0% and 15% or less;
• and
• (c) annealing the washed active material in air at 400 to 1000° C. without adding an additional lithium precursor to obtain a reusable active material.