Abstract:A recycling process including separation of electrode materials by ultrasonic treatment, acid leaching, Fe-removing, precipitation of cobalt, nickel, manganese and lithium has been applied successfully to recycle spent lithium-ion batteries and to synthesize LiNi_1/3Co_1/3Mn_1/3O₂. When ultrasonic treatment with 2-nitroso-4-methylphenol(NMP) at 40 ℃ for 15 min, the electrode materials are separated completely. Above 99% of Co, Ni, Mn and Li, 95% of Fe in the separated electrodes are acid-leached in the optimized conditions of 2 mol/L H₂SO₄, 1׃2 H₂O₂׃H₂SO₄ (molar ratio), 70 ℃, 1׃10 initial S׃L ratio, and 1 h. 99.5% of Fe and less than 1% of Co, Ni, Mn in the leaching solution can be removed in the conditions of initial pH value 2.0−2.5 adjusted by adding 18% Na₂CO₃, 90 ℃ and stirring time 3 h. After adjusted to be equal by adding NiSO₄, CoSO₄ and MnSO₄ solution, 97.1% of Ni, Co, Mn in the Fe-removing surplus leaching solution can be recovered as Ni_1/3Co_1/3Mn_1/3(OH)₂. 94.5% of Li in the surplus filtrate after the deposition of Co, Ni and Mn can be recovered as Li₂CO₃. The LiNi_1/3Co_1/3Mn_1/3O₂, prepared from the recovered compounds, is found to have good characteristics of the layered structure and elecrtochemical performance.

Key words: recycling process; spent Li-ion batteries; cathode material; LiNi_1/3Co_1/3Mn_1/3O₂