Separation of valuable materials from spent lithium-ion battery based on granulation regulation

Abstract

Recycling of spent lithium-ion batteries has attracted worldwide attention to ensure sustainability of electric vehicle industry. Pretreatment as an essential step for recycling of spent LIBs is critical to ensure the recovery efficiency and quality of black mass which is used for further materials regeneration. Usually, high temperature pyrolysis, at around 600 °C is required during the pretreatment to achieve effective separation of the black mass that is binding on aluminium foils with polyvinylidene fluoride binder. In this research, a low temperature and energy effective method is demonstrated by introducing a controlled frictional granulation in the subsequent step. With heat treatment at below 300 ℃, the oxidation of aluminium foil and generation of fluorine-containing waste gas can be highly supressed. As a consequence, the recovery rate of black mass can be increased to 98.80 % with only 0.05 % Al loss. Compared with the high-temperature pyrolysis and shear crushing methods, the energy consumption was significantly reduced by 48.74 %. Additionally, the proportion of aluminium particles below 75 μm was reduced from 12.6 % to 1.9 % comparing with traditional high temperature pyrolysis, which eliminates the possibility of explosion of aluminium particles. This research provides a low-carbon footprint strategy for treatment of complex electronic waste.