Separation and recovery of valuable metals from spent lithium-ion batteries via concentrated sulfuric acid leaching and regeneration of LiNi1/3Co1/3Mn1/3O2

Abstract

Recycling of spent lithium ion batteries (LIBs) is an urgent task in the view of environmental protection, resources reuse and sustainable development of battery industry. Our work presents a new method for recovery of Al foils and cathode materials from LIBs via a simple process. The concentrated sulfuric acid (18.4 M H2SO4) solution are used as both separation and leaching agent. The complete separation of cathode materials from Al foils and the complete leaching of Li are achieved simultaneously after leaching for 1 h at 80 °C and solid/liquid ratio of 800 g L−1. Under these conditions, the leaching efficiencies of Ni, Co and Mn reached 25.6%, 23.2% and 18.3%, respectively, and the polyvinylidene fluoride (PVDF) binder is partially decomposed. The concentrated sulfuric acid destroys the structures of cathode materials and PVDF but prevents the Al dissolution by formation of the passivation film, which contributes to the separation of cathode materials from Al foils and no loss of Al foil. After removal of Al foils and adding the 4.5 vol% H2O2 solution to further leach the remaining suspension for 70 min at 70 °C, and the metals of Ni, Co and Mn in the cathode materials are totally leached into the solution. The amount of H2SO4 consumed by leaching 1 kg cathode pieces was 23 mol, which is less than the required acid consumption for the traditional acid leaching process. The leaching solution is precipitated step by step to obtain high purity Ni1/3Co1/3Mn1/3(OH)2 and Li2CO3. The obtained Ni1/3Co1/3Mn1/3(OH)2 and Li2CO3 are regenerated to LiNi1/3Co1/3Mn1/3O2 materials with excellent electrochemical performance.