Improved Advanced Oxidation Process for In Situ Recycling of Al Foils and Cathode Materials from Spent Lithium-Ion Batteries

The efficient recycling of spent lithium-ion batteries, especially cathodes, with a minimized environmental footprint is pivotal for the benign development of the new-energy automobile industry. However, effective exfoliation of cathode materials from Al foils is one of the current bottlenecks in pretreatment prior to the metallurgical recycling process. Herein, a novel process was proposed for the in situ peeling off of cathode materials from Al foils by improved advanced oxidation processes in the ultrasonic-assisted S2O82--Fe2+ (UASF) system. In this system, S2O82- was used as a free radical generator with Fe2+ as the catalyst, which can significantly promote the peeling-off efficiency. Experimental results indicate that all coating materials can be exfoliated from Al foils under the optimized operating conditions. The peeling-off mechanism indicates that binders (polyvinylidene fluoride, PVDF) were effectively degraded by free radicals of SO4 center dot- and (OH)-O-center dot generated in UASF, resulting in in situ liberation of cathode materials from Al foils. Further characterization results indicate that Al foils and cathode materials retain their original states, indicating that only the PVDF binders were degraded without destruction of other components. It is expected that this technology is a green and efficient candidate for in situ recycling of cathode materials and Al foils.