Lithium iron phosphate (LiFePO) batteries are currently becoming the primary power system for electric vehicles. However, after the life period, the heavy amounts of electric cars would give rise to a great number of scrapped LiFePO batteries, which inevitably causes serious environmental pollution and resources waste problems. Therefore, it is much imperative and urgent to develop the green technology for regenerating and recycling these scrapped LiFePO batteries. Herein, we reported an efficient and straightforward solid-phase strategy to achieve the direct regeneration of scrapped LiFePO cathode materials. The decommissioned LiFePO was successfully regenerated by adding lithium carbonate and melamine under the heat treatment condition, and the battery performance was repaired. The electrochemical performance of regenerated LiFePO is even higher than that of the unused LiFePO at 0.05 C. Moreover, the regenerated LiFePO also exhibits excellent capacity preservation rate of 99.03 % after 200 cycles and outstanding rate capability at 5 C with a discharge capacity of 116 mAh/g. The systematical study demonstrates that the nitrogen-doped carbon coatings play vital role in improving the properties of regenerated LiFePO cathode materials. This work provides a potential approach to resolve the scrapped LiFePO cathode materials to meet the coming retired tide of lithium ion batteries.

中文翻译：

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氮掺杂碳涂层高价值LiFePO4正极材料的直接再生

磷酸铁锂（LiFePO）电池目前正在成为电动汽车的主要动力系统。然而，电动汽车寿命结束后，大量的磷酸铁锂电池会产生大量报废，不可避免地造成严重的环境污染和资源浪费问题。因此，开发对这些报废磷酸铁锂电池进行再生和循环利用的绿色技术势在必行。在此，我们报道了一种有效且简单的固相策略来实现报废的 LiFePO 正极材料的直接再生。在热处理条件下添加碳酸锂和三聚氰胺，成功对报废的LiFePO进行再生，修复了电池性能。再生LiFePO在0.05 C时的电化学性能甚至高于未使用的LiFePO。此外，再生LiFePO在200次循环后还表现出优异的容量保持率，高达99.03%，在5 C时具有出色的倍率性能，放电容量为116 mAh /G。系统研究表明，氮掺杂碳涂层对于改善再生LiFePO正极材料的性能起着至关重要的作用。这项工作为解决报废的LiFePO正极材料提供了一种潜在的途径，以应对即将到来的锂离子电池退役潮。