During the thermal treatment process of spent LiFePO4 batteries in the recycling process,easy oxidation of the materials can lead to difficulties in subsequent selective lithium extraction.The comprehensive pyrolysis process for the full composition of spent LiFePO4 batteries was proposed,which effectively removes organic matter while inhibiting the oxidation of the phosphorus iron lithium mineral phase.Under the optimal pyrolysis conditions of an N2 atmosphere at 400℃for 45 minutes,the phosphorus iron lithium mineral phase remains stable without oxidation,achieving a lithium leaching rate of 99.03%.Gas chromatography-mass spectrometry(GC-MS)and gas chromatography(GC)analyses reveale that the early stage of pyrolysis mainly involves the volatilization and decomposition of the electrolyte,while the later stage is characterized by the pyrolysis of the separator and binder.The inhibitory effect of low-oxygen multi-component pyrolysis on the oxidation of phosphorus iron lithium was also investigated.The results show that the oxidation rate of phosphorus iron lithium during full-component pyrolysis is only 10.12%,a reduction of 86.58%compared to the pyrolysis of the cathode alone.The proposed comprehensive pyrolysis process for spent LiFePO4 batteries provides a novel approach for the pyrolytic recycling and efficient extraction of lithium.
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