Preparation and Electrochemical Performance of Nano-Co_3O_4 Anode Materials from Spent Li-Ion Batteries for Lithium-Ion Batteries

摘要

A hydrometallurgical process for the recovery of cobalt oxalate from spent lithium-ion batteries was used to recycle cobalt compound by using alkali leaching,reductive acid leaching and chemical deposition of cobalt oxalate.The recycled cobalt oxalate was used to synthesize nano-Co3O4 anode material by sol-gel method. The samples were characterized by thermal gravity analysis and differential thermal analysis（TGA/DTA）,X-ray diffraction（XRD）,scanning electron microscopy（SEM） and charge/discharge measurements.The influence of molar ratio of Co2+ to citric acid and calcination temperature on the structure and electrochemical performance of nano-Co3O4 was evaluated.As the molar ratio of Co2+ to citric acid is 1:1,the face-centered cubic（fcc） Co3O4 powder shows the discharge capacity of 760.9 mA h g-1,the high coulombic efficiency of 99.7%in the first cycle at the current density of 125 mA g-1,and the excellent cycling performance with the reversible capacity of 442.3 mA h g-1after 20 cycles at the current density of 250 mA g-1.