Cascade Extraction of Lithium in Anode of Waste Lithium-Ion Battery

The capacity of the waste lithium-ion battery directly affects its recycling value. Use the battery test system to classify waste lithium-ion batteries according to the different retention capacity. Ultrasonic pretreatment and sulfuric leaching experiments of the classified anode materials were performed at 30℃. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), inductively coupled plasma (ICP) atomic emission spectroscopy and laser particle size analyzer were used to characterize the anode materials and leaching process of different lithium-ion batteries. The results showed that about 28% of the used lithium-ion batteries maintained a capacity of more than 75%, the battery cycle performance was good and the Li content of the anode material was relatively low, which was suitable for the overall reuse. With the decrease of the holding capacity, the battery cycle performance was attenuated and the Li content of the anode was gradually increased. In the capacity range of 25%~50%, the battery cycle performance was rapidly attenuated and the anode Li content peaked, which was suitable for the Li extraction. When the holding capacity was high, the anode Li was mostly water-soluble components present in the surface SEI (solid electrolyte interphase) film, which could be recovered by direct water leaching to reach 84.52% recovery. As the retention capacity decreased, more Li element was in the form of non-water-soluble components such as LiF, and relatively more Li entered the interior of the graphite. The recovery rate of water leaching or direct acid leaching was not appropriate. After ultrasonic pretreatment, the sulfuric acid leaching could reach 98% recovery. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.