Synthesis of LiCoO 2 nano powders using recycled cobalt precursors from waste WC-Co hard metal

Abstract

LiCoO 2, a cathode material for lithium rechargeable batteries, was prepared using recycled Co 3O 4. First, cobalt powders were separated from waste WC-Co hard metal with an acid-base chemical treatment. Subsequently, Co 3O 4 powders were prepared by thermal treatment of the resulting Co(OH) 2. By adding a predetermined amount of LiOH · H 2O, LiCoO 2 was obtained by sintering for 10 h in air at 800 °C. Nano-sized LiCoO 2 was obtained by thermal treatment of the LiOH-coated Co 3O 4 particles at 500 °C for 3 h. LiOH was coated onto the Co 3O 4 particles by a sonochemical method. The synthesized micro- and nanoLiCoO 2 particles using recycled Co precursors were characterized by X-ray diffraction (XRD) and a scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis.