Recycling of LiNi_1/3Co_1/3Mn_1/3O₂ in waste lithium-ion batteries by N-methyl-pyrrolidone

An easily industrialized method for the synthesis of LiNi_1/3Co_1/3Mn_1/3O₂ from waste lithium-ion batteries (LIBs) is developed in this study. The positive electrode-active material is recycled by N-methyl-pyrrolidone (NMP) and calcination without using organic acid to leach metal. The recycling process parameters, including reaction time, reaction temperatures and solid–liquid ratios, are used to optimize the recycling process. The results show that the reaction time of 20 min, the temperature of 60°C and the solid–liquid ratio of 80 g l^–1 lead to a recovery rate of 82%. Carbonates are added to the recycled material to adjust the metal ion ratios and the structures to re-synthesize LiNi_xCo_yMn_zO₂ (LNCMO). The structure of the re-synthesized LNCMO is characterized by X-ray diffraction analysis and scanning electron microscopy. Electrochemical tests suggest that the waste LIBs can be recycled to re-synthesize new cathode materials with good electrochemical performance, which is comparable to the cathode materials prepared with commercial chemicals.