Advancements in recycling technologies for spent lithium-ion batteries (LIBs) are moving toward environmentally friendly and lower carbon approaches. This study presents a novel method for lithium extraction from spent LIBs based on a multipotential field membrane coupling process involving nanofiltration (NF), reverse osmosis (RO), and selective electrodialysis (SED). Lithium is extracted from the leaching liquor of spent LIBs containing multiple ions by using NF. The combined effects of the Donnan steric hindrance and dielectric exclusion determine the retention rates of each ion. Divalent ions such as Ni²⁺, Co²⁺, and Mn²⁺ experience stronger repulsion during the mass transfer process, resulting in rejection rates all above 98%, which is advantageous for the selective separation of lithium ions, and the recovery rate of lithium in the NF stage reached 96.02%. Considering the characteristics of the leaching liquor, which is acidic and high in chloride, the DK membrane is selected for its superior comprehensive performance from the three commercial NF membranes, with a particular focus on assessing the long-term separation performance stability and tolerance. Finally, the NF separation is coupled with the RO concentration and SED concentration processes to achieve efficient separation and enrichment of lithium. The lithium-ion concentration reached 15.23 g/L, and a Li₂CO₃ product with a main content of 99.82% is prepared, providing an efficient and environmentally friendly method for lithium recovery from spent LIBs.

中文翻译：

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基于多电位场膜工艺强化的废旧锂离子电池锂的高效绿色回收


废旧锂离子电池 （LIB） 回收技术的进步正在朝着环保和低碳的方法发展。本研究提出了一种基于多电位场膜耦合过程的废锂离子电池提取锂的新方法，涉及纳滤 （NF）、反渗透 （RO） 和选择性电渗析 （SED）。使用 NF 从含有多个离子的废 LIB 的浸出液中提取锂。Donnan 空间位阻和介电排斥的综合效应决定了每个离子的保留率。Ni²⁺、Co²⁺ 和 Mn²⁺ 等二价离子在传质过程中受到较强的排斥力，导致截留率均在 98% 以上，有利于锂离子的选择性分离，NF 阶段锂的回收率达到 96.02%。考虑到浸出液呈酸性和高氯化物的特性，从三种商用 NF 膜中选择了 DK 膜，因为它具有卓越的综合性能，特别注重评估长期分离性能的稳定性和耐受性。最后，将 NF 分离与 RO 浓缩和 SED 浓缩过程相结合，以实现锂的高效分离和富集。锂离子浓度达到 15.23 g/L，制备了主含量为 99.82% 的 Li₂CO₃ 产品，为废锂离子电池的锂回收提供了一种高效、环保的方法。