Efficient and Green Recovery of Lithium from Spent\nLithium-Ion Batteries Based on a Multipotential Field Membrane Process\nIntensification

Advancements\nin recycling technologies for spent lithium-ion batteries\n(LIBs) are moving toward environmentally friendly and lower carbon\napproaches. This study presents a novel method for lithium extraction\nfrom spent LIBs based on a multipotential field membrane coupling\nprocess involving nanofiltration (NF), reverse osmosis (RO), and selective\nelectrodialysis (SED). Lithium is extracted from the leaching liquor\nof spent LIBs containing multiple ions by using NF. The combined effects\nof the Donnan steric hindrance and dielectric exclusion determine\nthe retention rates of each ion. Divalent ions such as Ni<sup>2+</sup>, Co<sup>2+</sup>, and Mn<sup>2+</sup> experience stronger repulsion\nduring the mass transfer process, resulting in rejection rates all\nabove 98%, which is advantageous for the selective separation of lithium\nions, and the recovery rate of lithium in the NF stage reached 96.02%.\nConsidering the characteristics of the leaching liquor, which is acidic\nand high in chloride, the DK membrane is selected for its superior\ncomprehensive performance from the three commercial NF membranes,\nwith a particular focus on assessing the long-term separation performance\nstability and tolerance. Finally, the NF separation is coupled with\nthe RO concentration and SED concentration processes to achieve efficient\nseparation and enrichment of lithium. The lithium-ion concentration\nreached 15.23 g/L, and a Li<sub>2</sub>CO<sub>3</sub> product with\na main content of 99.82% is prepared, providing an efficient and environmentally\nfriendly method for lithium recovery from spent LIBs.