Recycling of spent ternary lithium-ion batteries (LIBs) is crucial for both resource recovery and environmental sustainability. Deep eutectic solvents (DESs), as an eco-friendly leaching agent, offer a promising alternative to mineral acids for the metal recovery. However, current DES-based systems primarily focus on binary LiCoO 2 batteries and suffer from complex leaching conditions, including high operation temperature, long reaction time. Herein, a dual-function green solution is synthesized using choline chloride and tartaric acid, enabling direct precipitation of nickel (Ni) and separation of cobalt (Co), manganese (Mn), and lithium (Li) within 50 min at 100 °C, without requiring additional reducing agents throughout the process. The recovery efficiency of Li, Ni, Co, and Mn reached 99.2%, 97.3%, 94.4%, and 94.1%, respectively, while the purity of Ni products approached 99.9%. The used system is suitable for recycling various types of ternary batteries. Additionally, both theoretical and experimental analyses reveal that Ni ions exhibit superior binding energy and coordination with DESs compared to other ions, attributed to the synergistic effect of strong interaction and stable chelation. This research offers a promising method for the replenishment of essential metal resources.
Xingyu Hu,Hui Shi,Yilei Zheng,Penghui Shao,Liming Yang,Xubiao Luo
The sustainable recovery of valuable metals from end-of-life lithium-ion batteries (LIBs) has become essential for relieving the supply-demand contradiction of key resources. However, the high similarity in physicochemical properties of transition metals poses a fundamental challenge for the selective recycling. Here we proposed a facile strategy for defining the demarcation line of precipitation/dissolution behavior for precise Ni/Co separation. A malonic acid-based deep eutectic solvent (DES) is developed, emphasizing the H 2 O-mediated competitive coordination and differentiated solubility. We discovered the distinctive formation of [Ni(H 2 O) 6 ] 2+ and [CoCl 4 ] 2- in the DES-20 % H 2 O system. Furthermore, the K sp differences of the Ni-complex and Co-complex in the C 3 H 2 O 4 2- -rich environment was effectively magnified. These significant differences synergistically enable the generation of C 3 H 2 NiO 4 ·2H 2 O precipitation (∼ 99.9 % purity), achieving a remarkable Ni/Co separation factor of 125, which guarantees sequential separation of all metals. This universal methodology along with in-depth mechanism understanding provides a guideline toward value-added recovery of LIBs.
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