Spent lithium-ion battery recycling has attracted significant attention because of its importance in regard to the environment and resource importance. Traditional hydrometallurgical methods usually leach all valuable metals and subsequently extract target meals to prepare corresponding materials. However, Li recovery in these processes requires lengthy operational procedures, and the recovery efficiency is low. In this research, we demonstrate a method to selectively recover lithium before the leaching of other elements by introducing a hydrothermal treatment. Approximately 90% of Li is leached from high-Ni layered oxide cathode powders, while consuming a nearly stoichiometric amount of hydrogen ions. With this selective recovery of Li, the transition metals remain as solid residue hydroxides or oxides. Furthermore, the extraction of Li is found to be highly dependent on the content of transition metals in the cathode materials. A high leaching selectivity of Li (> 98%) and nearly 95% leaching efficiency of Li can be reached with LiNi_0.8Co_0.1Mn_0.1O₂. In this case, both the energy and material consumption during the proposed Li recovery is significantly decreased compared to traditional methods; furthermore, the proposed method makes full use of H⁺ to leach Li⁺. This research is expected to provide new understanding for selectively recovering metal from secondary resources.

废弃的锂离子电池回收因其对环境和资源的重要性而受到了广泛的关注。传统的湿法冶金方法通常会浸出所有有价值的金属，然后提取目标粗粉以制备相应的材料。然而，在这些过程中的锂回收需要冗长的操作步骤，并且回收效率低。在这项研究中，我们演示了一种通过引入水热处理在浸出其他元素之前选择性回收锂的方法。约90％的Li从高Ni层状氧化物阴极粉末中浸出，同时消耗了近化学计量的氢离子。通过对锂的这种选择性回收，过渡金属保留为固体残留物的氢氧化物或氧化物。此外，发现锂的提取高度依赖于阴极材料中过渡金属的含量。LiNi可以实现Li的高浸出选择性（> 98％）和Li的近95％浸出效率_0.8 Co _0.1 Mn _0.1 O ₂。在这种情况下，与传统方法相比，拟议的锂回收过程中的能源和材料消耗均显着降低；此外，所提出的方法充分利用了H ⁺来浸提Li ⁺。这项研究有望为从二次资源中选择性回收金属提供新的认识。