Research On Recovery And Reuse Technology Of Cathode Material Of Waste Power Battery

Lithium-ion battery is an excellent secondary battery,which has the advantages of high working voltage,large specific capacity,long cycle life and good safety performance.With the widespread use of lithium-ion batteries,a large number of waste lithium-ion batteries have appeared,and these waste lithium-ion batteries contain a large amount of valuable metals and toxic chemicals.If they are buried as municipal waste,they will pollute the environment.And a waste of resources.In addition,the content of valuable metals in lithium-ion batteries is concentrated in the cathode material,so the recycling of waste lithium-ion battery cathode materials is an urgent problem to be solved.In response to this problem,this article conducts research on the recovery and reuse technology of waste lithium iron phosphate power batteries and waste ternary lithium ion power battery cathode materials.The research content of this paper is as follows:（1）Determine the disassembly route of the lithium iron phosphate power battery: follow the steps of battery collection,module analysis,grading sorting,discharge treatment,cutting tabs,disassembling batteries and collecting positive and negative plates;（2）Two methods are studied to separate the positive electrode active material and the current collector: the current collector is recovered in the form of metal Al,and the positive pole pieces are calcined,vibrated and sieved,and soaked in lye to obtain clean aluminum foil.The current collector is recovered in the form of Al（OH）3.The positive pole pieces are mechanically crushed,alkaline leached,and acid neutralized to obtain Al（OH）3.The recovery rate of metal aluminum is as high as92%;（3）Three methods: LiFePO₄ regeneration,lithium and iron separation,and electrochemical extraction of lithium are used to recover the positive active material of lithium iron phosphate power batteries;（1）LiFePO₄ regeneration: Determine the metal content of the recovered material by ICP characterization,and then adjust The molar ratio of lithium,iron,and phosphorus in the recovered material is regenerated into LiFePO₄ as the positive electrode active material through the carbon-thermal high-temperature solid-phase reaction.The optimal reaction conditions in the regeneration process were studied,including reaction temperature and time,and the molar ratio of Fe:C.Finally,through the characterization and testing of the product,it was found that the product remained at 97 m Ah/g after 300 cycles,and it had good stability.（2）Separation of lithium and iron: The process of alkali dissolution-acid leaching-iron separation-lithium carbonate thermal precipitation is used to recoveraluminum,iron and lithium.The results show that the recovery rate of aluminum is as high as 92% and the recovery rate of lithium is as high as 98% Above,the iron recovery rate is as high as 98.7%.（3）Electrochemical recovery of lithium: The Fe PO₄ material is used to directly enrich the lithium in the solution from the cathode material solution through electrochemical methods,and the lithiated iron phosphate material is heat-treated to re-prepare the lithium iron phosphate cathode material;（4）Recycling of waste ternary lithium-ion power batteries,mainly studying the pretreatment of waste ternary lithium-ion batteries,the separation of cathode materials and current collectors（determine the best separation conditions with regard to material-to-liquid ratio,temperature,and time）.The ternary recycled material is re-synthesized to a new ternary material through the high-temperature solid phase method.Perform a series of morphology characterization and electrochemical performance tests on the re-synthesized ternary materials;（5）Research on the economic benefits of the recycling and reuse of waste lithium iron phosphate cathode materials.After analyzing the product cost and elaborating the sales of recycled products,the research shows that the recycling of waste lithium iron phosphate batteries has certain economic benefits.As the recycling of used batteries is not only conducive to environmental protection,but also conducive to the recycling of resources,so as to determine the need for research.