Preparation of Co3O4 hollow microspheres by recycling spent lithium-ion batteries and their application in electrochemical supercapacitors

Abstract Lithium-ion batteries (LIBs) have been growing rapidly to meet the increasing commercial demand of electric vehicles and portable electronic devices. However, the extensive use of LIBs has also brought many environmental problems. Thus, the recycling and reuse of spent LIBs has attracted wide attention. Although, a lot of work has been done to recover scarce metals from the spent LIBs, the studies on the preparation of nanostructured cobalt oxide (Co3O4) materials by recycling the spent LIBs are rarely reported. Herein, the Co3O4 hollow microspheres were prepared using the leaching solution of the spent LIBs as cobalt source via a facile solvothermal method followed by a calcination process. The morphology and structure were characterized by different techniques. The results indicate that those Co3O4 hollow microspheres (Φ∼1 μm) possess numerous mesopores, which is favorable for the preparation of high performance supercapacitor electrode. The Co3O4 hollow microspheres exhibit relatively high specific capacitance (SC) and good stability. The excellent electrochemical properties should be attributed to the synergetic effect of hollow microstructure, large specific surface area and numerous mesopores. This study proved the feasibility to prepare Co3O4 nanostructures from the leaching solution of the spent LIBs, which is promising for industrial recovery and reuse of the spent LIBs.