Preparation and electrochemical properties of Co3O4 nanorod arrays from the spent lithium-ion batteries

In this work, Co3O4 nanorod arrays were synthesized by a template free solvothermal method and a subsequent calcination process with the leaching solution of the spent lithium-ion batteries (LIBs) as the main raw materials. The as-synthesized samples were measured by XRD, SEM, etc. The results show that the as-synthesized nanorods with an average diameter of 200 nm and a mean length of 4 μm are composed of many nanoparticles, and a large number of mesoporous structures are permeated on the surface of the nanorods. The potential application of the products with mesoporous structures in supercapacitors was investigated. The results display that the as-synthesized samples have high capacitance and good cycle stability. The specific capacitance (SC) is 418 F g−1, and as much as 89.5% of its initial capacitance can be maintained after 1000 charge–discharge cycles. This study testifies that it is feasible to synthesize Co3O4 nanorod arrays with the spent LIBs as the raw materials, which provides a new idea for the resource utilization of the spent LIBs.