Lithium nickel manganese cobalt oxide in the spent lithium ion batteries (LIBs) contains a lot of lithium, nickel, cobalt and manganese. However, how to effectively recover these valuable metals under the premise of reducing environmental pollution is still a challenge. In this work, a green, efficient, closed-loop direct regeneration technology is proposed to reconstruct LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) cathode materials from spent LIBs. Firstly, the failure mechanism of NCM523 cathode materials in the spent LIBs is analyzed deeply. It is found that the spent NCM523 material has problems such as the dissolution of lithium and transition metals, surface interface failure and structural transformation, resulting in serious deterioration of electrochemical performance. Then NCM523 material was directly regenerated by supplementing metal ions, granulation, ion doping and heat treatment. Meanwhile, PO₄^3- polyanions were doped into the regenerated NCM material in the recovery process, showing excellent electrochemical performance with discharge capacity of 189.8 mAh g^-1 at 0.1 C. The recovery process proposed in this study puts forward a new strategy for the recovery various lithium nickel cobalt manganese oxide (e.g., LiNi_1/3Co_1/3Mn_1/3O₂, LiNi_0.5Co_0.2Mn_0.3O₂, LiNi_0.6Co_0.2Mn_0.2O₂ and LiNi_0.8Co_0.1Mn_0.1O₂) and accelerates the industrialization of spent lithium ion battery recycling.

废锂离子电池（LIB）中的锂镍锰钴氧化物包含大量锂，镍，钴和锰。然而，如何在减少环境污染的前提下有效地回收这些有价值的金属仍然是一个挑战。在这项工作中，提出了一种绿色，高效，闭环直接再生技术来重建LiNi _0.5 Co _0.2 Mn _0.3 O ₂（NCM523）废旧LIB的阴极材料。首先，深入分析了废旧锂离子电池中NCM523正极材料的失效机理。发现用过的NCM523材料具有诸如锂和过渡金属的溶解，表面界面破坏和结构转变之类的问题，从而导致电化学性能的严重恶化。然后通过补充金属离子，造粒，离子掺杂和热处理直接再生NCM523材料。同时，在回收过程中将PO ₄ ^3-聚阴离子掺杂到再生的NCM材料中，表现出优异的电化学性能，放电容量为189.8 mAh g ^-1本研究提出的回收工艺提出了一种回收各种锂镍钴锰氧化物的新策略（例如，LiNi _1/3 Co _1/3 Mn _1/3 O ₂，LiNi _0.5 Co _0.2 Mn _0.3 O_{如图2所示}，LiNi _0.6 Co _0.2 Mn _0.2 O ₂和LiNi _0.8 Co _0.1 Mn _0.1 O ₂）促进了废锂离子电池回收的工业化。