Recycling And Application Of Cathode Materials For Ternary Lithium-ion Batteries

The service life limit of lithium-ion batteries will inevitably produce a large number of waste lithium-ion batteries to pollute the environment.This project mainly analyzes the composition of cathode materials of waste lithium-ion batteries,removes impurities contained in cathode materials,recycles valuable metals and synthesizes ternary cathode materials to form a closed cycle,which is of great significance for protecting the environment and saving resources.The main findings are as follows:（1）Material analysis and impurity removal and reduction acid leaching and purification.XRD,SEM,FT-IR analysis showed that the main components of the cathode materials of waste lithium-ion batteries were nickel,cobalt,manganese and aluminum,and the substances containing C were PVDF and NMP,and conductive carbon.The optimal process conditions for the leaching of waste ternary lithium-ion battery materials by H₂SO₄/H₂O₂ system were determined.The results show that the concentrations of nickel,cobalt and manganese leached in 100 m L of leaching solution under optimal conditions were 0.2583,0.1873 and 0.2114 mol/L in 100 m L of lubate after taking 2 g of cathode material,respectively.（2）Optimize the process parameters of recovery of nickel,cobalt and manganese by chemical precipitation.Optimize the amount of hydrogen peroxide,p H,reaction temperature in the process of primary selective manganese precipitation.The chemical precipitant NH₄HCO₃ was used to precipitate manganese to recover manganese,and the recovered product manganese carbonate was obtained,and XRD and SEM analysis was carried out,and the purity of the recovered product was high,there was no impurity phase,and the morphology was spherical.The filtrate after the primary selective precipitation of manganese was used to separate nickel-cobalt ions at the second stage,and the amount of EDTA added,sodium hydroxide dosage and ammonia distillation time in the process of separating nickel-cobalt by chemical precipitation were optimized.Taking（NH₄）₂C₂O₄ as precipitant,optimizing the reaction temperature,p H,reaction time,ammonium oxalate addition and other conditions in the process of cobalt sedimentation,cobalt was recovered in the form of Co C₂O₄,XRD and SEM analysis were carried out on the recovered product cobalt oxalate,and the recovered product contained a certain impurity phase,which was crystalline Na OH,and the microscopic morphology was rectangular.After selective manganese precipitation of nickel-cobalt solution,the Ni-EDTA complex was broken by UV/H₂O₂ method,sodium carbonate was added to precipitate nickel ions,and finally existed as a mixture of nickel carbonate and nickel hydroxide to characterize XRD and SEM.XRD is an amorphous phase peak,and the microscopic morphology is blocky.（3）Solid-phase grinding recovery products are synthesized into ternary battery cathode materials.The recovery products manganese carbonate,cobalt oxalate,basic nickel carbonate solid-phase grinding and resynthesis of Li Ni_1/3Co_1/3Mn_1/3O₂ cathode materials,the first discharge specific capacity at 0.2C was 171.14 m Ah/g,and the capacity retention rate after 50 cycles was 65.83%.