Enhanced Extraction Of Valuable Metals From Spent Lithium-ion Batteries With Mechanochemistry Process

Lithium-ion batteries（LIBs）have been extensively applied in modern electronic devices due to their superior performance,such as long cycle life,strong adaptability under high and low temperature,light weight and high energy density,etc.Therefore,an increasing number of LIBs will be discarded annually.Based on the analysis of the composition of LIBs,recycling the valuable metals from the spent LIBs has environmental and economic benefits.Recycling of valuable metals from spent lithium-ion batteries（LIBs）is desirable for resource recovery and environmental protection.This paper focuses on the hydrometallurgical recovery of valuable metals from pure LiCoO₂ and LiCoO₂ pretreated by activated carbon.In the work,hydrometallurgical recovery of valuable metals from spent LIBs was enhanced by the mechanical activation process.The leaching rates of both Co and Li increased dramatically with increasing the ball milling time,rotation speed and ball-to-powder mass ratio.The recovery of Co and Li increased with increasing the concentration of leachates,while the leaching rates of metals decreased dramatically with the increase of solid to liquid.In addition,the leaching rates of Co and Li were both higher than those of the unactivated samples,indicating that mechanical activation process could enhance the metal recovery.Moreover,the leaching kinetics results showed that the mechanical activation process could alter the leaching behavior of valuable metals.Ultimately,the recovery of Co and Li from actual cathode materials disassembled from the spent LIBs was also explored.The leaching rates of Co and Li were 93.4%and 100%,respectively.This efficient mechanical activation process is of great significance for recovering valuable metals from the spent LIBs under mild conditions.In order to discover the effect of reducing agent in this system,activated carbon is added in the experiment due to strong reducibility,simple price,low experimental cost.In another system,the Co and Li were leached from LiCoO₂ which was mechanical activated with active carbon.Similarly,the effects of mechanochemical parameters were studied,such as milling time and ritation speed.Moreover,The mechanism of increasing the leaching efficiency with increasing the ball milling time and rotation speed was studied by characterizing the samples by SEM、BET、XRD、XPS.The LiCoO₂ was embedded into the activated carbon because of the destroyed morphology and crystal structure after mechanochemical process,which contributed to the improved leaching efficiency of Co and Li.Then,the leaching factors were also studied and the results presented that the recovery of Co and Li increased with increasing the concentration of H₂SO₄,while the leaching rates of metals decreased dramatically with the increase of solid to liquid.Moreover,the leaching kinetics results showed that the mechanical activation process could alter the leaching behavior of valuable metals.Also,the high recovery rates of metals can be obtained under 1 M H₂SO₄ and room temperature.The study of leaching kinetics indicated that the reaction was controlled by diffusion mainly for the milled samples and shown that the leaching rates were accelerated owing to the reductivity of activated carbon.Ultimately,the recovery of Co and Li from actual cathode materials disassembled from the spent LIBs was also explored.The leaching rates of Co and Li were 81.7%and 73.2%,respectively.This efficient mechanical activation process is of great significance for recovering valuable metals from the spent LIBs under mild conditions.