Novel ternary deep eutectic solvents used for recycling lithium and cobalt from waste lithium-ion batteries

• Published in: Separation and purification technology 2025-02, Vol.354, p.128934, Article 128934
• Main Authors: Liu, Ronghao, Li, Jun, Liu, Xiaoxia, Yin, Xiaolu, Yang, Yanzhao
• Format: Article
• Language: English
• Subjects: Efficient leaching; Lithium-ion batteries; Mechanism; Recovery; Ternary deep eutectic solvent
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.128934

[Display omitted] •Ternary DES can achieve more than 99.5% leaching efficiency of Co and Li from LIBs.•Acidity and coordination ability of DES were the main driving forces of leaching.•The leaching process were controlled by chemical reaction-controlled model.•Li and Co loaded DES phase can be separated by using oxalic acid.•Ternary DES improves the green property and reduces costs of the leaching process. The escalating disposal of lithium-ion batteries (LIBs) poses significant environmental challenges but also offers substantial opportunities for resource recovery. In this work, we introduce a recycling strategy using a green, cost-effective ternary deep eutectic solvent (DES) composed of guanidine hydrochloride, ethylene glycol, and maleic acid. The DES can achieve >99.5 % leach efficiency of lithium (Li) and cobalt (Co) at 100 °C, 9h, and L/S=50. The kinetic study found that the chemical reaction rate at the interface was the key to controlling the leaching process. The study of leaching mechanisms found that the acidity and coordination ability of DES were the main driving forces of leaching. Co loaded in the DES phase can almost precipitate out by using oxalic acid, achieving the separation of Li and Co. After reusing three times, the maximum load of Li in the DES phase reached 4.1 mg/g. These outstanding performances, along with the avoidance of the use of hazardous chemicals and the reduction of high costs, confirmed that the DES possesses a promising prospect for sustainable, large-scale application in efficiently leaching valuable metals from LiCoO2.