End-of-life lithium-ion batteries (LIBs) have received unprecedented consideration because of their potential environmental pollution and the value of decisive metal supplies. The dosage of over-stoichiometric amounts of acids, including all kinds of organic or inorganic acids, may result in corrosion of the equipment or production of toxic and harmful gases. Herein, an unconventional acid-free method-salt leaching to extract Ni, Co, Mn, and Li from a spent LiNi0.5Co0.2Mn0.3O2 cathode material using Fe(II) (reductant reagent) and Fe(III) (precipitation) is proposed. Under the condition with 0.2 mol/L Fe-2(SO4)(3), 0.36 mol/L FeSO4, 40 min, and 90 degrees C, the leaching efficiencies of Ni, Co, Mn, and Li are all higher than 96%. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) characterizations are applied for revealing the phase changes in leaching process. This new type of acid-free slat-leaching method provides a new idea for the recycling of spent LIBs containing metals such as nickel, cobalt, and manganese.

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