A Dual Closed-Loop Process to Recycle High Nickel Cathode of Spent Lithium-Ion Batteries via Deep Eutectic Solvents: Computational Screening and Experimental Validation

en Deep eutectic solvents (DESs) have displayed a significant potential in green recycling of spent lithium-ion batteries (LIBs) cathode materials. In this study, we proposed a computational screening strategy based on the binding energy and hydrogen bonding performance via density functional theory and molecular dynamic calculation, achieving a novel DES system composed of tetramethylammonium chloride (TMAC) and oxalic acid dihydrate (OA) for a dual closed-loop process to recycle LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode of spent LIBs. The binding energy between DESs and Li/Ni/Co/Mn ions were shown to critically influence metal leaching efficiency, implying that DESs with higher binding energy exhibited superior extraction performance. DES TMAC-OA was screened out as optimal potential, and then followed by experimental validations to achieve the leaching of valuable metals from spent NCM811 cathode powder in a much milder condition (80°C, 30 min) with high efficiency. Combined with the coordination regulation of water and ethanol, a high selectivity separation of Li and Ni/Co/Mn can be achieved to regenerate high-value precursors of NCM811 with both high purity and yield. The regenerated precursors can be used to produce new NCM811 with considerable electrochemical performances. More importantly, DESs can be perfectly regenerated and recycled many times, indicating that the process is cost-effective and eco-friendly. Such a strategy provides a feasibility basis to demonstrate a promising potential of DESs in the green recovery and recycling of valuable materials from spent LIBs, therefore benefiting the circular economy and the sustainable management of electronic waste. 摘要 zh 低共熔溶剂(DESs)在退役锂离子电池(LIBs)正极材料的绿色回收方面显示出巨大的潜力。在本研究中,我们提出了一种通过密度泛函理论(DFT)和分子动力学(MD)计算结合能(BE)和氢键性能,用以筛选低共熔溶剂的策略,优选出由四甲基氯化铵(TMAC)和草酸二水合物(OA)组成的DES,可实现退役锂电池NCM811(LiNi 0.8 Co 0.1 Mn 0.1 O 2 )正极材料的双循环回收工艺。DESs和Li/Ni/Co/Mn离子之间的结合能被证明对金属浸出效率有关键影响,而且结合能较高的DESs具有优异的金属浸取性能。浸取实验表明优选出的DES TMAC-OA可以在更温和的条件下(80°C,30分钟)从退役NCM811(S-NCM)正极粉中高效浸出有价金属。结合水和乙醇的配位调节,实现了Li和Ni/Co/Mn的高选择性分离,制备出高纯度和高收率的再生NCM811前驱体。使用再生前驱体可以重新合成出电化学性能优异的新NCM811正极。更重要的是,DES可以多次再生和循环使用,这表明该工艺具有较高的成本效益和环保特性。这一策略为低共熔溶剂从退役锂电池中绿色回收和再生高价值材料方面的巨大潜力提供了可行性基础,从而有利于循环经济和电子废物的可持续管理。