Self-activation of Ferro-chemistry based advanced oxidation process towards in-situ recycling of spent LiFePO4 batteries

Increasing application of lithium iron phosphate (LiFePO4) battery in electric vehicles (EVs) and hybrid electric vehicles (HEVs) is boosting the generation of spent lithium iron phosphate batteries. Sustainable and cost-effective recycling these batteries with less value-added metals is crucial for the fulfillment of circular economy society. Here, in-situ advanced oxidation metallurgy technology was innovatively proposed towards selective extraction of Li from LiFePO4 by Fenton oxidation, instead of conventional metallurgical processes. Li can be completely liberated without destructing olive type structure of LiFePO4 with the formation of FePO4 precursors. Mechanism revealed by DFT calculations and chemical reaction analysis indicates that the oxidation of Fe(II) in LiFePO4 and release of Li+ is mainly initiated by the rapid attack of a large number of •OH during advanced oxidation process. Liberated Li+ was recovered as Li2CO3 and used with FePO4 as precursors to re-fabricate LiFePO4. The recovered LiFePO4 shows sound electrochemical performances with initial discharge capacity of 138.9 mAh/g at 0.5C and capacity retention of 93.6% after 50 cycles. This study provides a green and efficient alternative for the selective recycling of Li from spent LiFePO4 battery based on its inherent structure and characteristics of target recycling materials with reduced chemical consumption, high efficiency and simplified recycling process.