Selective Lithium Extraction and Recycling of High-Value Metals from Spent LiNi<sub><i>x</i></sub>Co<sub><i>y</i></sub>Mn<sub>1–<i>x</i>–<i>y</i></sub>O<sub>2</sub> Cathode Materials
Baichao Zhang, Yunlong Xu, Fangjun Zhu, Jiangnan Huang, Jinqiang Gao, Lu Yang, Bai Song, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji
Abstract
The diversification of metal elements with similar physicochemical characteristics in lithium-ion batteries (LIBs) results in great challenges in the recycling of spent LIBs. Aiming at eco-friendly, efficient, and industrial-applicable recycling, we propose a novel carbothermic reduction strategy for selective extraction of lithium and sustainable recovery of high-value metals from spent LiNi x Co y Mn 1– x – y O 2 (NCM) cathode. The reduction mechanism and phase structure evolution of spent NCM revealed that the spent NCM microspheres are converted into multicomponent particles of water-soluble lithium salts (Li 2 CO 3 and Li 2 O) and water-insoluble M or MO (M = Ni, Co, Mn) after carbothermic reduction. Depending on the different properties of the reduced products, two different recycling routes were proposed based on disparate roasting temperatures. In the low-temperature route, 96.6% of Li can be selectively leached out by using water as the only leaching reagent after roasting at 550 °C for 1 h. For the high-temperature route, 98.1% of Li is selectively extracted by water leaching; after that, wet-magnetic separation was employed to collect transition metals depending on the magnetic differences of the product. In particular, the whole process is simple and eco-friendly and has no other chemical consumption. This work provides two efficient and environmentally friendly ways of recycling spent LIBs based on selective lithium extraction.