Direct Regeneration of LiNi_0.5Co_0.2Mn_0.3O₂ Cathode from Spent Lithium-Ion Batteries by the Molten Salts Method

Abstract

Recycling of spent lithium-ion batteries is extremely urgent with their increasing decommission. In this work, eutectic molten salts of LiOH–Li2CO3 used as lithium sources for direct regeneration of LiNi0.5Co0.2Mn0.3O2 were developed. Based on the phase diagram of LiOH and Li2CO3, the effects of different lithium sources on material regeneration have been investigated. The cathode materials regenerated with eutectic molten salts have high capacity, good cycling performance, and rate performance. The discharge capacities during the 1st and 200th cycles at 1 C are 146.3 and 130.3 mA h g–1, respectively, and the capacity retention rate reaches 89.06%. Using the combined X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) analysis, the original layered structure of spent cathode materials was restored. Therefore, the eutectic molten salt of LiOH–Li2CO3 is feasible for direct regeneration of spent cathode materials.