Nucleation–Oxidation coupled technology for High-Nickel ternary cathode recycling of spent Lithium-ion batteries

Abstract

Demand of ternary Li-ion batteries (LIBs) has risen dramatically in recent times, making it necessary to efficiently recycle spent cathode materials to reduce environmental pollution and alleviate the tight supply of various elements including Li, Co, and Ni. Co-precipitative regeneration of spent LIBs is typically employed to recycle Li, Co, Ni, and Mn. However, it is difficult to evenly distribute metals in the regenerated materials. Moreover, the emission of heavy-metal ions makes it difficult to meet the environmental guidelines. Here, we develop a nucleation–oxidation coupled technology to efficiently recover Ni, Co, and Mn from spent ternary cathodes by forming layered double hydroxides (LDHs) in a micro-liquid-film reactor. After recycling, 98% Li remains in the liquid phase, while the Ni, Co, and Mn in the filtrate decrease to the ppb level. Atomic distribution of Ni, Co, and Mn can be achieved in LDH, which helps realize the full-life-cycle of ternary cathode materials. It is difficult for the high-nickel ternary e.g., LiNi0.8Co0.1Mn0.1O2 to regenerate into LDH through spontaneous air oxidation. The micro-liquid-film reactor has a strong shear rate (maximum 1.04 × 106 s−1 is three orders of magnitude larger than that of the stirred reactor) and large vorticity (∼1.18 × 105 s−1, three orders of magnitude greater than that of the stirred reactor). It can enhance the transfer and diffusion of oxygen in the liquid phase. Hence, the micro-liquid-film reactor can greatly strengthen air-oxidation reaction of Ni2+, Co2+, and Mn2+ to sufficiently form trivalent cations, while the nucleation–oxidation-coupled regeneration is realized during the nucleation stage.