Selective Lithium Extraction and Recycling of High-Value Metals from Spent LiNixCoyMn1-x-yO2 Cathode Materials

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 LiNixCoyMn1-x-yO2 (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 (Li2CO3 and Li2O) 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 degrees 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.