Facile Synthesis and Li-Electroactivity of Cobalt Oxide Based on Resources Recovered from Waste Lithium-Ion Batteries

In this study, cobalt oxide (Co3O4) powder was prepared by simple precipitation and heat-treatment process of cobalt sulfate that is recovered from waste lithium-ion batteries (LIBs), and the effect of heat-treatment on surface properties of as-synthesized Co(OH)2 powder was systematically investigated. With different heat-treatment conditions, a phase of Co(OH)2 is transformed into CoOOH and Co3O4. The result showed that the porous and large BET surface area (ca. 116 m2/g) of Co3O4 powder was prepared at 200°C for 12 h. In addition, the lithium electroactivity of Co3O4 powder was investigated. When evaluated as an anode material for LIB, it exhibited good electrochemical performance with a specific capacity of about 500 mAh g–1 at a current density of C/5 after 50 cycles, which indicates better than those of commercial graphite anode material.