Regeneration of high-capacity Ni-rich layered cathode material from spent lithium-ion batteries

Abstract

Ever-growing demand for electric vehicles promotes manufacture of lithium-ion batteries (LIBs) and accelerates consumption of some rare resources such as lithium and cobalt. In addition, numerous spent LIBs are sent to recycling depots every year. To explore a high-efficiency resource reuse, high-capacity Ni-rich LiNi0.92Co0.05Mn0.03O2 is synthesized from a Ni-Co-Cu-Fe alloy powder, a crude product from recycling spent LIBs. The alloy is firstly treated by an oxygen-assistant acid leaching, and then purified to remove Fe2+ and Cu2+. The purified leachate after being adjusted in chemical composition is directly made into Ni0.92Co0.05Mn0.03(OH)2 precursor via a co-precipitation method. X-ray diffraction and scanning electron microscope measurements indicate that the regenerated cathode material is well-crystallized and has spherical morphology with an average diameter of 3 µm. Energy dispersive spectroscopy shows that the Fe and Cu in the raw material are eliminated thoroughly. The electrochemical performance is evaluated as well. The cathode material delivers an initial discharge capacity of 231.8 mAh g−1 at 0.1 C. When tested at 0.5 C, it exhibits an initial discharge capacity of 213.4 mAh g−1, and a capacity retention of 57.6% after 400 cycles. At a high current density of 5 C, it still has a discharge capacity of 178.3 mAh g−1.