Active Material Reuse Method Using Cathode Scrap

There is provided a method for collecting and reusing an active material from positive electrode scrap. The positive electrode active material reuse method of the present disclosure includes (a) thermally treating positive electrode scrap comprising a lithium composite transition metal 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, and (b) annealing the collected active material with an addition of a lithium precursor to obtain a reusable active material.