In-situ recycling of coating materials and Al foils from spent lithium ion batteries by ultrasonic-assisted acid scrubbing

• Published in: Journal of cleaner production 2020-06, Vol.258, p.120943, Article 120943
• Main Authors: Chen, Xiangping, Li, Shuzhen, Wu, Xin, Zhou, Tao, Ma, Hongrui
• Format: Article
• Language: English
• Subjects: Al foil; Coating materials; In-situ recycling; Spent lithium ion batteries; Ultrasonic-assisted acid scrubbing
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2020.120943

Efficient recycling of valuable components, especially high value-added parts, from spent lithium ion batteries (LIBs) is of great importance to alleviate or avert current environment-related issues and growing resources depletion. Current study established a novel process for in-situ separation and recycling of both coating materials and Al foils from spent LIBs using ultrasonic-assisted acid scrubbing method. Waste cathodes obtained after pretreatment were cut into smaller pieces, put into a self-designed ultrasonic reactor and immersed in different aqueous solutions for scrubbing experiments. Experimental data proves that acidic solutions (i.e. sulfuric and oxalic acidic media), even quite dilute solutions, can significantly improve peeling off efficiency and Al purity, instead of pure water ultrasonic scrubbing. About 99%, 100% and 46% coating materials can be detached in sulfuric acidic, oxalic acidic and pure water medium, respectively, leaving these Al foils with a corresponding purity of 98%, 99% and 15%. The possible cause for the prompt peeling off coating materials may be rapid degradation of binders by the strong oxidation of HO· radicals formed and strengthened in acidic ultrasonic solutions. Net profits of $2.587 or $2.043 per kg spent batteries can be achieved in sulfuric or oxalic acidic ultrasonic scrubbing system. This recycling process may suggest an alternative for in-situ recycling of cathode materials and Al foils from spent LIBs, with simplified separation procedure and enhanced recycling efficiency and product purity. Synopsis: HO· radicals formed in mild acidic ultrasonic solutions can facilitate the prompt degradation of PVDF binder for subsequent in-situ recycling of Al foils and cathode materials. [Display omitted] •Ultrasonic-assisted acid scrubbing is applied during the exfoliation process.•Cathode materials and Al foils can be in-situ recovered as their original forms.•High purity products can be simultaneously obtained under optimized conditions.•Prompt exfoliation may attributed to HO· formed in acidic ultrasonic solution.