Sustainable regeneration of high-performance cathode materials from spent lithium-ion batteries through magnetic separation and coprecipitation

Abstract

Extensive research and application of recycling methods for spent lithium-ion batteries (LIBs) have been undertaken in recent years with great success. However, the separation of valuable metals from the lixivium of spent LIBs, which contains Al, Cu, Ni, Co, Mn, and Li, is complicated, burdensome, and unsustainable. Therefore, there is a need to establish a more sustainable and energy-efficient method for recycling spent LIBs. The study introduced an innovative methodology for replacing the impurity ion removal process in the lixivium with magnetic separation pretreatment. Then, the co-precipitation method was used to directly resynthesize LiNi0.5Co0.2Mn0.3O2 (LNCM523) with recovered metals as raw materials. The results demonstrate that, with a magnetic field intensity of 3000 Oe and feed particle size of −0.074 mm, the magnetic separation concentrates the following grades: Ni-26.34%, Co-14.26%, Mn-28.30%, Al-0.23%, and Cu-0.41%. The corresponding recovery rates were also determined as follows: Ni-92.57%, Co-94.16%, Mn-85.68%, Al-1.62%, and Cu-2.14%. The total impurities (Al, Cu, and Fe) in the lixivium obtained by magnetic separation concentrate under conventional acid leaching conditions were below 0.05 wt%, while the contents of Ni, Co, and Mn were measured at 13.08 g/L, 7.10 g/L, and 14.06 g/L, respectively. Spherical LNCM523 was successfully regenerated from the lixivium through co-precipitation and sintering. The LNCM523 demonstrated exceptional electrochemical performance, exhibiting a notable initial discharge capacity of 173.9 mAh/g at 0.2 C and remarkable cycling stability with 91.9% retention over 100 cycles at 0.5 C. In comparison to the conventional approach, this method circumvented the intricate procedure of separating metal ions, thereby realizing the resource regeneration of cathode materials and enabling a closed-circuit recycling process. These advancements contributed to fostering sustainable low-carbon development of the spent LIBs.