Regenerating of LiNi_0.5Co_0.2Mn_0.3O₂ cathode materials from spent lithium-ion batteries

An acidless process route for regenerating LiNi_0.5Co_0.2Mn_0.3O₂ materials is applied in this work. The regenerated LiNi_0.5Co_0.2Mn_0.3O₂ materials are prepared by calcining the mixture of LiOH·H₂O and the spent LiNi_0.5Co_0.2Mn_0.3O₂ materials. The regeneration process with different ratio of Li/Li_st (Li content in commercial LiNi_0.5Co_0.2Mn_0.3O₂) from 12 to 16% is extensively investigated. Remarkably, the regenerated materials with Li/Li_st for 14% possesses optimal discharge capacity (161.25 mAh g^− 1 at 0.1 °C), enhanced rate performance and cycling stability (with capacity retention of 95.29% after cycling at 0.5 °C for 50 cycles) compared to spent LiNi_0.5Co_0.2Mn_0.3O₂ (with initial capacity of 40.35 mAh g^− 1 and retention of 79.55% after cycling at 0.5 °C for 50 cycles). The Rietveld refinement, X-ray photoelectron spectroscopy (XPS) and further Electrochemical impedance spectroscopy (EIS) indicate these improved electrochemical performance can be account for the increase of active lithium, lower cation mixing degree and impedance. The results indicate the approach to regenerating of LiNi_0.5Co_0.2Mn_0.3O₂ is feasible.