Abstract: The binder of the scrap electrode was removed by heat treatment and the spent LiFePO₄ was oxidized to Li₃Fe₂(PO₄)₃ and Fe₂O₃ at the same time. The Li₃Fe₂(PO₄)₃ and Fe₂O₃ were used as starting materials to regenerate LiFePO₄ by carbothermal reduction method with glucose, citric acid monohydrate and polyethylene glycol as reducing agent respectively. The regeneration reactions occurred at 650℃ for 16h, 20h and 24h, respectively. The results showed that the pure phase regenerated LiFePO₄ material was obtained by the three reductant systems. When the glucose worked as reducing agent in regeneration reactions for 16h, 20h and 24h, the initial specific discharge capacities of the regenerated materials were 118.49mA·h/g, 118.38mA·h/g, 123.77mA·h/g, respectively. After 100 cycles, the capacities retention rates were 88.40%, 80.07% and 72.56%, respectively. The effect of reducing agent on the performance of regeneration materials was significant. Both the specific discharge-discharge capacity and cycle performance of regeneration materials were optimal, when the glucose worked as reducing agent. The regeneration materials with polyethylene glycol reductant system showed the worst electrochemical performance. This research provided an effective route for the regeneration of the spent LiFePO₄ cathode materials in lithium-ion batteries.

Key words: spent Li-ion battery, lithium iron phosphate, recovery, regeneration, carbothermal reduction route

摘要： 采用热处理方法将回收的正极片除去黏结剂，同时将LiFePO₄氧化为Li₃Fe₂（PO₄）₃及Fe₂O₃并作为再生反应原料，分别以葡萄糖、一水合柠檬酸、聚乙二醇为还原剂，650℃高温反应16h、20h、24h碳热还原再生LiFePO₄。测试结果表明，3个还原剂体系均能获得再生LiFePO₄材料。以葡萄糖为还原剂，高温反应16h、20h、24h，放电比容量分别为118.49mA·h/g、118.38mA·h/g、123.77mA·h/g；100次循环后，容量保持率分别为88.40%、80.07%、72.56%。还原剂对再生材料性能影响显著，以葡萄糖为还原剂，再生材料的容量特性及循环性能均最优，一水合柠檬酸还原剂体系次之，聚乙二醇还原剂体系电化学性能最差。研究结果为大规模废旧LiFePO₄材料再生提供一种新的途径。

关键词: 废旧电池, 磷酸铁锂, 回收, 再生, 碳热还原法