Recycling of LiFePO4 cathode materials from spent lithium-ion batteries through ultrasound-assisted Fenton reaction and lithium compensation

Efficient exfoliation of cathode materials from current collectors for their direct regeneration is the typical bottleneck during spent lithium ion batteries (LIBs) recycling due to the strong adhesion of PVDF (polyvinylidene fluoride) binders. Ultrasound-assisted Fenton reaction was innovatively applied for the selective removal of PVDF binders to recover cathode materials of LiFePO4 from current collectors and the recovered LiFePO4 was regenerated through lithium compensation, targeting for the in-situ recycling of cathode materials from spent LIBs. Experimental results suggest that the PVDF binders were adequately degraded by hydroxyl radical (center dot OH) generated from Fenton's reagent with reinforcement of ultrasound, and about 97% cathode materials can be scrubbed from Al foils under optimized conditions. Detailed analytical results support that the cathode materials peeled off from current collectors are free from contamination of effluent, and the recovered LiFePO4 can be directly re-fabricated as new cathode materials through lithium compensation with little reduction of electrochemical performances. And the tentative mechanism investigation for pathway of center dot OH generation and chemical reactions indicates that center dot OH generated from Fenton's reagent with the reinforcement of ultrasound can effectively degrade PVDF binders. This work can be a green and efficient candidate for the in-situ recycling of cathode materials of LiFePO4 from spent LIBs.

Automated summary

This study successfully applied ultrasound-assisted Fenton reaction to selectively remove PVDF binders from spent LIBs, recovering LiFePO4 cathode materials. Experimental results showed that under optimized conditions, about 97% of the cathode materials can be scrubbed from the aluminum foils, and the cleaned materials are free from contamination.