Transformation process of valuable metals in the recycling of spent lithium-ion batteries and the potential environmental impact
With the rapid development of the new energy electric vehicle industry,a significant volume of spent lithium-ion batteries require safe disposal.The valuable metals in the cathode materials of these batteries can be recycled and reused due to their intrinsic value.Nevertheless,the potential secondary pollution affecting the environment and workers'health during the recycling process warrants attention.This study details the transformation process and mechanism of valuable metals during the three stages of pretreatment,recycling,and regeneration,with a focus on the composition and structure of spent lithium-ion batteries.The effects of impurity elements on the recycling of valuable metals and the corresponding modification methods are discussed.Initially,the impact of the electrolyte,organic binder,and collector aluminum foil on the separation of cathode materials in the pretreatment stage is elucidated.Subsequently,the reaction mechanisms of valuable metals and influencing factors are examined through methods such as pyrometallurgy,hydrometallurgy,and regeneration.The characteristics of these methods are summarized from the perspectives of recycling efficiency,energy and material consumption,and environmental impact.Lastly,this study reviews the development and prospects of the recycling techniques for valuable metals from spent lithium-ion batteries,aiming to provide a scientific basis and methodological reference for the efficient recycling and utilization of these metals.