Method for recycling waste ternary battery cathode material
By functionalizing and regenerating the cathode materials of spent ternary lithium batteries, a self-healing regenerated cathode material is formed, solving the problem of poor cycle performance and achieving long battery life and high energy storage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RUICHI NEW ENERGY (XUZHOU) CO LTD
- Filing Date
- 2025-12-30
- Publication Date
- 2026-07-21
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials, specifically a method for regenerating cathode materials from waste ternary lithium batteries. Background Technology
[0002] As my country's ternary lithium battery industry continues to expand, the resource utilization of a large number of waste ternary lithium batteries helps promote the comprehensive utilization of resources and the development of a circular economy. At the same time, it is also of great significance to alleviate the shortage of mineral resources and protect the ecological environment. As a "second mine" that has emerged in this century, the resource utilization of waste ternary lithium batteries has become an important research topic for relevant scientific researchers. The recycling methods of waste ternary lithium battery cathode materials mainly include pyrometallurgical recycling, wet recycling and direct regeneration.
[0003] Ternary lithium batteries are commonly used energy storage devices in electronic products and electric vehicles. However, their capacity decays relatively quickly, especially under improper use, and their lifespan can be significantly reduced in a short period. Taking ternary lithium batteries as an example, during charging and discharging, lithium tungstate consumes residual lithium on the surface of the ternary active material, leading to a decrease in the surface residual lithium content, which in turn affects the battery's cycle performance and reduces its lifespan. Therefore, this application introduces a recycled waste ternary lithium battery cathode material with good cycle stability. Summary of the Invention
[0004] A method for regenerating waste ternary lithium battery cathode material, wherein the waste ternary lithium battery cathode material is prepared by polymerizing 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, and methyldimethoxysilane, reacting them with 4-vinylphenylboronic acid, and finally polymerizing them with 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine, and hexafluorodianhydride, mixing them with carbon black and functionalized recycled ternary materials, coating them on the surface of aluminum foil, and drying them. The functionalized recycled ternary material is prepared by discharging, disassembling, removing glue, calcining, alkali washing, lithium replenishment, and crushing a ternary lithium-ion battery, polymerizing polythiophene on its surface, and then reacting it sequentially with 2,6-di-tert-butyl-4-bromomethylphenol and (1-methyl-imidazol-5-yl)methylamine.
[0005] As an optimization, the method for regenerating the cathode material of the waste ternary lithium battery mainly includes the following steps: (1) Mix the recycled material and lithium carbonate at a mass ratio of 45~55:8~10, grind to 100~200 mesh, calcine at 780~820℃ for 9~11h under pure oxygen atmosphere with a heating rate of 2℃ / min, crush to a particle size of 12~14μm, soak in deionized water for 25~35min, and vacuum dry at -10~0℃ to obtain recycled ternary material; (2) The modified recycled ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate and methanol are mixed in a mass ratio of 4~6:1:1:1.1~1.3:13~15, stirred at 60~64℃ and 200~300r / min for 8~10h, filtered, washed with methanol 3~5 times, and vacuum dried at -10~0℃ for 22~26h to obtain the functionalized recycled ternary material; (3) Mix the adhesive, carbon black and functionalized recycled ternary material at a mass ratio of 1:0.08~0.12:1 and stir at 45~55℃ and 800~1000r / min for 2~3h to obtain the electrode slurry. Use aluminum foil as the carrier fluid and control the electrode slurry to be uniformly coated on the surface with a thickness of 20~30μm. Dry at 40~60℃ for 8~12h and use a slicer to make a disc with a diameter of 10mm. Vacuum dry at -10~0℃ for 12~16h to obtain the recycled positive electrode material.
[0006] As an optimization, the recycled material in step (1) is prepared by soaking a ternary lithium-ion battery in a 4-6 wt% sodium chloride aqueous solution for 46-50 h, vacuum drying at room temperature for 14-16 h, disassembling the battery, taking the positive electrode sheet, drying it at 40-60℃ for 16-18 h, crushing it to a particle size of 0.18-0.22 mm, placing it in N,N-dimethylformamide, stirring it at 70-90℃ and 300-500 r / min for 1.8-2.2 h, filtering it, vacuum drying it at -10-0℃ for 22-24 h, calcining it in a pure oxygen atmosphere at 480-520℃ for 1.8-2.2 h, cooling it to room temperature, placing it in a 1 mol / L sodium hydroxide aqueous solution, stirring it at room temperature and 300-500 r / min for 1.8-2.2 h, filtering it, and drying it at 80-90℃ for 1.8-2.2 h.
[0007] As an optimization, the modified recycled ternary material in step (2) is prepared by mixing propanol and methanol at a volume ratio of 1:4~6 to obtain a mixed solvent, mixing the pre-modified recycled ternary material, 2,6-di-tert-butyl-4-bromomethylphenol and the mixed solvent at a mass ratio of 4~6:1:16~20, stirring at 55~65℃ and 200~300rmin for 11~13h, filtering, washing with diethyl ether 4~6 times, and vacuum drying at -10~0℃ for 22~26h.
[0008] As an optimization, the pre-modified regenerated ternary material is prepared by uniformly mixing ferric chloride and chloroform at a mass ratio of 1:8~10 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and the regenerated ternary material are mixed at a mass ratio of 4~6:1:16~20:4~6, stirred at 200~300 r / min for 3~5 min, heated to 30~40℃, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform is added uniformly over 8~10 min, stirring is continued for 46~50 h, filtered, washed 3~5 times with ethanol, and vacuum dried at -10~0℃ for 22~26 h.
[0009] As an optimization, the adhesive in step (3) is prepared by mixing modified siloxane, 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and N-methylpyrrolidone in a mass ratio of 2~3:8~10:3~5:160~170, stirring at 200~300r / min for 3~5min to obtain an amino mixture, adding hexafluorodianhydride at 0.43~0.47 times the molar amount of amino in the amino mixture, and continuing to stir for 100~140min.
[0010] As an optimization, the modified siloxane is prepared by uniformly mixing chloroplatinic acid and deionized water at a mass ratio of 1:80~100 to obtain an aqueous solution of chloroplatinic acid; mixing polysiloxane, deionized water and aqueous solution of chloroplatinic acid at a mass ratio of 8~10:20:0.4~0.6, stirring at 60~70℃ and 200~300r / min for 3~5min, adding an equimolar amount of 4-vinylphenylboronic acid of methyldimethoxysilane at a uniform rate over 8~10min, continuing stirring for 4~6h, removing the aqueous phase, washing with deionized water 3~5 times, and vacuum drying at -10~0℃ for 22~26h.
[0011] As an optimization, the polysiloxane is prepared by mixing 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, methyldimethoxysilane and deionized water in a mass ratio of 1:4~6:1:16~24, adjusting the pH to 5 with 0.1mol / L hydrochloric acid aqueous solution, stirring at 200~300r / min for 20~30min at room temperature, raising the temperature to 70~80℃, stirring for 100~120min, removing the aqueous phase, washing 3~5 times with deionized water, and vacuum drying at -10~0℃ for 22~26h.
[0012] As an optimization, the carbon black in step (3) is 20nm conductive carbon black.
[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention involves the following steps in the regeneration of waste ternary lithium-ion battery cathode materials: discharging, disassembling, removing adhesive, calcining, alkali washing, lithium replenishment, and pulverizing the ternary lithium-ion battery; polymerizing polythiophene on its surface; and then reacting it sequentially with 2,6-di-tert-butyl-4-bromomethylphenol and (1-methyl-imidazol-5-yl)methylamine to obtain a functionalized regenerated ternary material. 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, and methyldimethoxysilane are polymerized, then reacted with 4-vinylphenylboronic acid, and finally polymerized with 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine, and hexafluorodianhydride. This mixture is then combined with carbon black and the functionalized regenerated ternary material, coated onto an aluminum foil surface, and dried to obtain the regenerated ternary lithium-ion battery cathode material.
[0014] First, a ternary lithium-ion battery is discharged, disassembled, degummed, calcined, alkaline washed, lithium replenished, and pulverized. Polythiophene is then polymerized on its surface, followed by sequential reactions with 2,6-di-tert-butyl-4-bromomethylphenol and (1-methylimidazol-5-yl)methylamine to obtain a functionalized regenerated ternary material. After regenerating the cathode material, polythiophene is polymerized on its surface. As a conductive polymer, polythiophene coats the surface of the regenerated ternary material, acting as an organic SEI layer. This effectively regulates the uniform distribution of lithium-ion flux on the lithium metal surface and withstands the volume expansion of lithium metal during battery cycling, thereby inhibiting the formation and growth of lithium dendrites. This mechanism helps... To improve battery cycle stability; it then reacts with 2,6-di-tert-butyl-4-bromomethylphenol, loading hindered phenol onto the surface. The hindered phenol can capture free radicals generated during polymer oxidation, interrupting the free radical chain reaction and thus preventing further oxidative degradation, extending the lifespan of polythiophene and adhesives, and consequently extending battery life. Finally, it reacts with (1-methyl-imidazolium-5-yl)methylamine. The imidazolium insertion provides more binding sites for lithium ions, promoting lithium ion desolvation and diffusion reactions, improving battery cycle stability, and enabling the battery to store more energy per unit volume or mass. Secondly, 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, and methyldimethoxysilane are polymerized, then reacted with 4-vinylphenylboronic acid, and finally polymerized with 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine, and hexafluorodianhydride. This mixture is then mixed with carbon black and functionalized recycled ternary materials, coated onto the surface of aluminum foil, and dried to obtain the recycled ternary battery cathode material. The introduction of phenylboronic acid into the polysiloxane allows it to form a six-membered ring, which, if broken, can reform at room temperature, exhibiting excellent self-healing properties. This allows for rapid repair of adhesives at room temperature, reducing the contact area between the electrolyte and the cathode material, thereby reducing side reactions and extending battery life. Detailed Implementation
[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0016] Example 1: A method for regenerating cathode materials from waste ternary lithium batteries mainly includes the following steps: (1) The ternary lithium-ion battery was soaked in a 4wt% sodium chloride aqueous solution for 46h, vacuum dried at room temperature for 14h, disassembled, the positive electrode sheet was taken, dried at 40℃ for 16h, pulverized to a particle size of 0.18mm, placed in N,N-dimethylformamide, stirred at 70℃ and 300r / min for 1.8h, filtered, vacuum dried at -10℃ for 22h, then calcined at 480℃ for 1.8h in a pure oxygen atmosphere, cooled to room temperature, and placed in a 1mol container. The recycled material was prepared by stirring in a 1 / L sodium hydroxide aqueous solution at 300 rpm for 1.8 h at room temperature, filtering, and drying at 80 °C for 1.8 h. The recycled material and lithium carbonate were mixed at a mass ratio of 45:8, ground to 100 mesh, calcined at 780 °C for 9 h under a pure oxygen atmosphere at a heating rate of 2 °C / min, pulverized to a particle size of 12 μm, soaked in deionized water for 25 min, and vacuum dried at -10 °C to obtain the recycled ternary material. (2) Ferric chloride and chloroform were mixed evenly at a mass ratio of 1:8 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and recycled ternary material were mixed at a mass ratio of 4:1:16:4, stirred at 200 r / min for 3 min, heated to 30℃, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform was added at a uniform rate over 8 min, and stirring was continued for 46 h. After filtration, the mixture was washed three times with ethanol and vacuum dried at -10℃ for 22 h to obtain a pre-modified recycled ternary material; propanol and methanol were mixed evenly at a volume ratio of 1:4 to obtain a mixed solvent, and the pre-modified recycled ternary material was prepared. Modified recycled ternary material, 2,6-di-tert-butyl-4-bromomethylphenol, and a mixed solvent were mixed at a mass ratio of 4:1:16, stirred at 55℃ and 200 rpm for 11 h, filtered, washed four times with diethyl ether, and vacuum dried at -10℃ for 22 h to obtain the modified recycled ternary material; the modified recycled ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate, and methanol were mixed at a mass ratio of 4:1:1:1.1:13, stirred at 60℃ and 200 rpm for 8 h, filtered, washed three times with methanol, and vacuum dried at -10℃ for 22 h to obtain the functionalized recycled ternary material; (3) Mix 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, methyldimethoxysilane and deionized water in a mass ratio of 1:4:1:16, adjust the pH to 5 with 0.1 mol / L hydrochloric acid aqueous solution, stir at 200 r / min for 20 min at room temperature, raise the temperature to 70℃, stir for 100 min, remove the aqueous phase, wash 3 times with deionized water, and vacuum dry at -10℃ for 22 h to obtain polysiloxane; mix chloroplatinic acid and deionized water in a mass ratio of 1:80 to obtain chloroplatinic acid aqueous solution; mix polysiloxane, deionized water and chloroplatinic acid aqueous solution in a mass ratio of 8:20:0.4, stir at 200 r / min for 3 min at 60℃, add 4-vinylphenylboronic acid in an equal molar amount of methyldimethoxysilane within 8 min, continue stirring for 4 h, remove the aqueous phase, and wash 3 times with deionized water. Modified siloxane was prepared by vacuum drying at -10℃ for 22 h. The modified siloxane, 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine, and N-methylpyrrolidone were mixed at a mass ratio of 2:8:3:160 and stirred at 200 r / min for 3 min to obtain an amino mixture. Hexafluorodianhydride was added at 0.43 times the molar amount of amino in the amino mixture, and stirring was continued for 100 min to obtain an adhesive. The adhesive, carbon black, and functionalized regenerated ternary material were mixed at a mass ratio of 1:0.08:1 and stirred at 45℃ and 800 r / min for 2 h to obtain an electrode slurry. Using aluminum foil as the carrier fluid, the electrode slurry was uniformly coated on the surface with a thickness of 20 μm and dried at 40℃ for 8 h. The slurry was then sliced into 10 mm diameter discs and vacuum dried at -10℃ for 12 h to obtain the regenerated cathode material.
[0017] Example 2: A method for regenerating cathode materials from waste ternary lithium batteries mainly includes the following steps: (1) The ternary lithium-ion battery was soaked in a 5wt% sodium chloride aqueous solution for 48h, vacuum dried at room temperature for 15h, disassembled, the positive electrode sheet was taken, dried at 50℃ for 17h, crushed to a particle size of 0.2mm, placed in N,N-dimethylformamide, stirred at 80℃ and 400r / min for 2h, filtered, vacuum dried at -5℃ for 23h, calcined at 500℃ for 2h in a pure oxygen atmosphere, cooled to room temperature, placed in a 1mol / L sodium hydroxide aqueous solution, stirred at 400r / min at room temperature for 2h, filtered, dried at 85℃ for 2h to obtain recycled material, the recycled material and lithium carbonate were mixed at a mass ratio of 50:9, ground to 150 mesh, heated to 800℃ at a pure oxygen atmosphere at a heating rate of 2℃ / min, calcined for 10h, crushed to a particle size of 13μm, soaked in deionized water for 30min, vacuum dried at -5℃ to obtain regenerated ternary material; (2) Ferric chloride and chloroform were mixed evenly at a mass ratio of 1:9 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and recycled ternary material were mixed at a mass ratio of 5:1:18:5, stirred at 250 r / min for 4 min, heated to 35℃, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform was added at a uniform rate within 9 min, and stirring was continued for 48 h. After filtration, the mixture was washed 4 times with ethanol and dried under vacuum at -5℃ for 24 h to obtain a pre-modified recycled ternary material; propanol and methanol were mixed evenly at a volume ratio of 1:5 to obtain a mixed solvent, and the pre-modified recycled ternary material was prepared. Modified recycled ternary material, 2,6-di-tert-butyl-4-bromomethylphenol, and a mixed solvent were mixed at a mass ratio of 5:1:18, stirred at 60℃ and 250 rpm for 12 h, filtered, washed 5 times with diethyl ether, and vacuum dried at -5℃ for 24 h to obtain the modified recycled ternary material; the modified recycled ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate, and methanol were mixed at a mass ratio of 5:1:1:1.2:14, stirred at 62℃ and 250 rpm for 9 h, filtered, washed 4 times with methanol, and vacuum dried at -5℃ for 24 h to obtain the functionalized recycled ternary material; (3) Mix 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, methyldimethoxysilane and deionized water in a mass ratio of 1:5:1:20, adjust the pH to 5 with 0.1 mol / L hydrochloric acid aqueous solution, stir at 250 r / min for 25 min at room temperature, raise the temperature to 75℃ and stir for 110 min, remove the aqueous phase, wash 4 times with deionized water, and vacuum dry at -5℃ for 24 h to obtain polysiloxane; mix chloroplatinic acid and deionized water in a mass ratio of 1:90 to obtain chloroplatinic acid aqueous solution; mix polysiloxane, deionized water and chloroplatinic acid aqueous solution in a mass ratio of 9:20:0.5, stir at 250 r / min for 4 min at 65℃, add 4-vinylphenylboronic acid in an equal molar amount of methyldimethoxysilane at a uniform rate within 9 min, continue stirring for 5 h, remove the aqueous phase, and wash 4 times with deionized water. Modified siloxane was prepared by vacuum drying at -5℃ for 24 h. The modified siloxane, 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and N-methylpyrrolidone were mixed in a mass ratio of 2.5:9:4:1605 and stirred at 250 r / min for 4 min to prepare an amino mixture. Hexafluorodianhydride was added at 0.45 times the molar amount of amino in the amino mixture and stirred for another 120 min to prepare an adhesive. The adhesive, carbon black and functionalized regenerated ternary material were mixed in a mass ratio of 1:0.1:1 and stirred at 50℃ and 900 r / min for 2.5 h to prepare an electrode slurry. Using aluminum foil as the carrier fluid, the electrode slurry was uniformly coated on the surface with a thickness of 25 μm and dried at 50℃ for 10 h. The slurry was then cut into discs with a diameter of 10 mm using a slicing machine and vacuum dried at -5℃ for 14 h to obtain the regenerated cathode material.
[0018] Example 3: A method for regenerating cathode materials from waste ternary lithium batteries mainly includes the following steps: (1) The ternary lithium-ion battery was soaked in a 6wt% sodium chloride aqueous solution for 50h, vacuum dried at room temperature for 16h, disassembled, the positive electrode sheet was taken, dried at 60℃ for 18h, pulverized to a particle size of 0.22mm, placed in N,N-dimethylformamide, stirred at 90℃ and 500r / min for 2.2h, filtered, vacuum dried at 0℃ for 24h, then calcined at 520℃ for 2.2h in a pure oxygen atmosphere, cooled to room temperature, and placed in 1mol The recycled material was prepared by stirring the solution of sodium hydroxide in a sodium hydroxide aqueous solution at 500 rpm for 2.2 h at room temperature, filtering, and drying at 90 °C for 2.2 h. The recycled material and lithium carbonate were mixed at a mass ratio of 55:10, ground to 200 mesh, calcined at 820 °C for 11 h under a pure oxygen atmosphere at a heating rate of 2 °C / min, pulverized to a particle size of 14 μm, soaked in deionized water for 35 min, and vacuum dried at 0 °C to obtain the recycled ternary material. (2) Ferric chloride and chloroform were mixed evenly at a mass ratio of 1:10 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and the recycled ternary material were mixed at a mass ratio of 6:1:20:6, stirred at 300 r / min for 5 min, heated to 40℃, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform was added at a uniform rate over 10 min, stirred for 50 h, filtered, washed 5 times with ethanol, and vacuum dried at 0℃ for 26 h to obtain the pre-modified recycled ternary material; propanol and methanol were mixed evenly at a volume ratio of 1:6 to obtain a mixed solvent, and the mixture was then... Pre-modified recycled ternary material, 2,6-di-tert-butyl-4-bromomethylphenol, and a mixed solvent were mixed at a mass ratio of 6:1:20, stirred at 65℃ and 300 rpm for 13 h, filtered, washed 6 times with diethyl ether, and vacuum dried at 0℃ for 26 h to obtain the modified recycled ternary material; the modified recycled ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate, and methanol were mixed at a mass ratio of 6:1:1:1.3:15, stirred at 64℃ and 300 rpm for 10 h, filtered, washed 5 times with methanol, and vacuum dried at 0℃ for 26 h to obtain the functionalized recycled ternary material; (3) Mix 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, methyldimethoxysilane and deionized water in a mass ratio of 1:6:1:24, adjust the pH to 5 with 0.1 mol / L hydrochloric acid aqueous solution, stir at 300 r / min for 30 min at room temperature, raise the temperature to 80℃ and stir for 120 min, remove the aqueous phase, wash 5 times with deionized water, and vacuum dry at 0℃ for 26 h to obtain polysiloxane; mix chloroplatinic acid and deionized water in a mass ratio of 1:100 to obtain chloroplatinic acid aqueous solution; mix polysiloxane, deionized water and chloroplatinic acid aqueous solution in a mass ratio of 10:20:0.6, stir at 70℃ and 300 r / min for 5 min, add 4-vinylphenylboronic acid in an equal molar amount of methyldimethoxysilane within 10 min, continue stirring for 6 h, remove the aqueous phase, and wash with deionized water. Modified siloxane was prepared by vacuum drying at 0℃ for 26 h five times. Modified siloxane, 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and N-methylpyrrolidone were mixed at a mass ratio of 3:10:5:170 and stirred at 300 r / min for 5 min to prepare an amino mixture. Hexafluorodianhydride was added at a molar amount of 0.47 times that of the amino mixture and stirred for another 140 min to prepare an adhesive. The adhesive, carbon black and functionalized regenerated ternary material were mixed at a mass ratio of 1:0.12:1 and stirred at 55℃ and 1000 r / min for 3 h to prepare an electrode slurry. Aluminum foil was used as the carrier fluid, and the electrode slurry was uniformly coated on the surface with a thickness of 30 μm. The slurry was dried at 60℃ for 12 h and then shaped into 10 mm diameter discs using a slicing machine. The discs were then vacuum dried at 0℃ for 16 h to obtain the regenerated cathode material.
[0019] Comparative Example 1: The difference between the recycling method of waste ternary battery cathode material in Comparative Example 1 and Example 2 lies in the difference in step (2). Step (2) is modified as follows: ferric chloride and chloroform are mixed evenly at a mass ratio of 1:9 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and recycled ternary material are mixed at a mass ratio of 5:1:18:5, stirred at 250 r / min for 4 min, heated to 35°C, and under nitrogen protection, an equal mass of chloroform is added at a uniform rate within 9 min. The ferric chloride mixture was stirred for 48 hours, filtered, washed four times with ethanol, and vacuum dried at -5°C for 24 hours to obtain the pre-modified regenerated ternary material. Propanol and methanol were mixed uniformly at a volume ratio of 1:5 to obtain a mixed solvent. The pre-modified regenerated ternary material, 2,6-di-tert-butyl-4-bromomethylphenol, and the mixed solvent were mixed at a mass ratio of 5:1:18, stirred at 60°C and 250 rpm for 12 hours, filtered, washed five times with diethyl ether, and vacuum dried at -5°C for 24 hours to obtain the functionalized regenerated ternary material. The remaining steps were the same as in Example 2.
[0020] Comparative Example 2: The difference between the recycling method of the waste ternary battery cathode material in Comparative Example 2 and Example 2 lies in step (2). Step (2) is modified as follows: Ferric chloride and chloroform are mixed evenly at a mass ratio of 1:9 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and recycled ternary material are mixed at a mass ratio of 5:1:18:5, stirred at 250 r / min for 4 min, heated to 35°C, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform is added uniformly within 9 min. Stirring is continued for 48 h, filtered, washed 4 times with ethanol, and vacuum dried at -5°C for 24 h to obtain the functionalized recycled ternary material. The remaining steps are the same as in Example 2.
[0021] Comparative Example 3: The method for regenerating the spent ternary lithium battery cathode material in Comparative Example 3 differs from that in Example 2 in that the regenerated ternary lithium material is not modified. The remaining steps are the same as in Example 2.
[0022] Comparative Example 4: The difference between the recycling method of waste ternary battery cathode material in Comparative Example 4 and Example 2 lies in the difference in step (3). Step (3) is modified as follows: 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and N-methylpyrrolidone are mixed in a mass ratio of 2.5:9:4:1605 and stirred at 250 r / min for 4 min to obtain an amino mixture. Hexafluorodianhydride is added at a molar amount of 0.45 times that of the amino mixture and stirred for another 120 min to obtain an adhesive. The adhesive, carbon black and functionalized recycled ternary material are mixed in a mass ratio of 1:0.1:1 and stirred at 50°C and 900 r / min for 2.5 h to obtain an electrode slurry. Aluminum foil is used as the carrier fluid, and the electrode slurry is uniformly coated on the surface with a thickness of 25 μm. It is dried at 50°C for 10 h and then made into a disc with a diameter of 10 mm using a slicing machine. It is then vacuum dried at -5°C for 14 h to obtain the recycled cathode material. The remaining steps are the same as in Example 2.
[0023] Test Example 1: Cyclic stability test: All electrochemical tests in this experiment were conducted by assembling the electrode materials into CR2032 coin cells. The battery assembly was carried out in an argon-filled glove box. The assembly sequence was as follows: positive electrode shell, positive electrode sheet, separator, electrolyte, lithium metal negative electrode, steel sheet, spring sheet, graphite. After the coin cell was assembled, it was quickly removed and sealed under a hydraulic sealing machine. Then, the sealed coin cell was wiped and left to stand for 10 hours to allow the electrolyte to fully wet the electrode sheet before testing. The cycling performance was tested by measuring the metal ion content in the electrode sheet after cycling: at a current density of 1C (1C=170mA·h / g) and a voltage of 2.6~4.2V, 500 cycles of lithium ion intercalation and deintercalation were performed, and the capacity retention rate was measured and recorded as M0. Self-healing test: Make 10 cuts 20μm deep and 3cm long on the surface of the positive electrode of the battery, let it stand at room temperature for 24h, and test the capacity retention rate according to the cycle performance test method, which is recorded as M1; Durability test: The battery was left to stand at 50℃ for 5 days, and the capacity retention rate was tested according to the cycle performance test method, which was recorded as M2. The results are shown in Table 1; As can be seen from the comparison of experimental data in Table 1, the ternary battery cathode material regenerated by the present invention has high durability, self-healing properties and good cycle stability.
[0024] A comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 1 in Table 1 reveals that M0 is larger in Examples 1, 2, and 3. The difference between Comparative Example 1 and Examples 1 is that imidazole was not grafted onto the surface of polythiophene. The insertion of imidazole provides more binding sites for lithium ions, promotes the desolvation and diffusion reaction of lithium ions, and improves the cycle stability of the battery. A comparison of the experimental data from Examples 1, 2, 3 and Comparative Example 3 reveals that M0 is larger in Examples 1, 2, and 3. The difference between Comparative Example 3 and the Examples is that polythiophene was not formed on the surface of the recycled ternary material. Polythiophene, as a conductive polymer, is coated on the surface of the recycled ternary material. As an organic SEI layer, polythiophene can effectively regulate the uniform distribution of lithium ion flux on the lithium metal surface and withstand the volume expansion of lithium metal during battery cycling, thereby inhibiting the formation and growth of lithium dendrites. This mechanism helps to improve the cycle stability of the battery. A comparison of the experimental data from Examples 1, 2, 3 and Comparative Example 4 reveals that M1 is larger in Examples 1, 2, and 3. The difference between Comparative Example 4 and the Examples is that phenylboronic acid was not introduced into the adhesive, but into the polysiloxane of the adhesive. These can form a six-membered ring, which can be reformed at room temperature if it breaks, exhibiting good self-healing properties. It can quickly repair the adhesive at room temperature, reduce the contact area between the electrolyte and the positive electrode material, thereby reducing the occurrence of side reactions and extending the battery's lifespan. A comparison of the experimental data from Examples 1, 2, and 3 and Comparative Example 2 reveals that M2 is larger in Examples 1, 2, and 3. The difference between Comparative Example 2 and the Examples is that hindered phenols did not form on the surface of the recycled ternary material. Hindered phenols can interrupt the free radical chain reaction by capturing free radicals generated during polymer oxidation, thereby preventing further oxidative degradation, extending the lifespan of polythiophene and the adhesive, and ultimately extending the battery's lifespan. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for regenerating cathode materials from waste ternary lithium batteries, characterized in that, The cathode material of the waste ternary battery is prepared by polymerizing 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane and methyldimethoxysilane to obtain polysiloxane, then reacting the polysiloxane with 4-vinylphenylboronic acid to obtain modified siloxane, and finally polymerizing the modified siloxane with 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and hexafluorodianhydride to obtain an adhesive. The adhesive is then mixed with carbon black and functionalized recycled ternary material, coated on the surface of aluminum foil, and dried. The functionalized regenerated ternary material is prepared by discharging, disassembling, degumming, calcining, alkaline washing, lithium replenishment, and pulverizing a ternary lithium-ion battery. Polythiophene is polymerized on the surface of the regenerated ternary material to obtain a pre-modified regenerated ternary material. The pre-modified regenerated ternary material is then mixed with 2,6-di-tert-butyl-4-bromomethylphenol to obtain a modified regenerated ternary material. Finally, the modified regenerated ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate, and methanol are mixed and reacted at 60-64°C to obtain the final product.
2. The method for regenerating waste ternary lithium battery cathode material according to claim 1, characterized in that, The method for regenerating the cathode material of the waste ternary lithium battery includes the following steps: (1) Mix the recycled material and lithium carbonate at a mass ratio of 45~55:8~10, grind to 100~200 mesh, calcine at 780~820℃ for 9~11h under pure oxygen atmosphere with a heating rate of 2℃ / min, crush to a particle size of 12~14μm, soak in deionized water for 25~35min, and vacuum dry at -10~0℃ to obtain recycled ternary material; (2) The modified recycled ternary material, (1-methyl-imidazol-5-yl)methylamine, piperidine, trimethyl orthoformate and methanol are mixed in a mass ratio of 4~6:1:1:1.1~1.3:13~15, stirred at 60~64℃ and 200~300r / min for 8~10h, filtered, washed with methanol 3~5 times, and vacuum dried at -10~0℃ for 22~26h to obtain the functionalized recycled ternary material; (3) Mix the adhesive, carbon black and functionalized recycled ternary material at a mass ratio of 1:0.08~0.12:1 and stir at 45~55℃ and 800~1000r / min for 2~3h to obtain the electrode slurry. Use aluminum foil as the carrier fluid and control the electrode slurry to be uniformly coated on the surface with a thickness of 20~30μm. Dry at 40~60℃ for 8~12h and use a slicer to make a disc with a diameter of 10mm. Vacuum dry at -10~0℃ for 12~16h to obtain the recycled positive electrode material.
3. The method for regenerating waste ternary lithium battery cathode material according to claim 2, characterized in that, The recycled material in step (1) is prepared by soaking a ternary lithium-ion battery in a 4-6 wt% sodium chloride aqueous solution for 46-50 h, vacuum drying at room temperature for 14-16 h, disassembling the battery, taking the positive electrode sheet, drying it at 40-60℃ for 16-18 h, crushing it to a particle size of 0.18-0.22 mm, placing it in N,N-dimethylformamide, stirring it at 70-90℃ and 300-500 r / min for 1.8-2.2 h, filtering it, vacuum drying it at -10-0℃ for 22-24 h, calcining it in a pure oxygen atmosphere at 480-520℃ for 1.8-2.2 h, cooling it to room temperature, placing it in a 1 mol / L sodium hydroxide aqueous solution, stirring it at room temperature and 300-500 r / min for 1.8-2.2 h, filtering it, and drying it at 80-90℃ for 1.8-2.2 h.
4. The method for regenerating waste ternary lithium battery cathode material according to claim 2, characterized in that, The modified recycled ternary material described in step (2) is prepared by mixing propanol and methanol at a volume ratio of 1:4~6 to obtain a mixed solvent. The pre-modified recycled ternary material, 2,6-di-tert-butyl-4-bromomethylphenol and the mixed solvent are mixed at a mass ratio of 4~6:1:16~20. The mixture is stirred at 55~65℃ and 200~300 rpm for 11~13 hours, filtered, washed with diethyl ether 4~6 times, and vacuum dried at -10~0℃ for 22~26 hours.
5. A method for regenerating waste ternary lithium battery cathode material according to claim 4, characterized in that, The pre-modified recycled ternary material is prepared by uniformly mixing ferric chloride and chloroform at a mass ratio of 1:8~10 to obtain a ferric chloride mixture; thiophene, 2-hydroxy-1,2-bis(2-thiophene)-ethyl ketone, chloroform and the recycled ternary material are mixed at a mass ratio of 4~6:1:16~20:4~6, stirred at 200~300 r / min for 3~5 min, heated to 30~40℃, and under nitrogen protection, an equal mass of ferric chloride mixture of chloroform is added uniformly over 8~10 min, stirring is continued for 46~50 h, filtered, washed 3~5 times with ethanol, and vacuum dried at -10~0℃ for 22~26 h.
6. A method for regenerating waste ternary lithium battery cathode material according to claim 2, characterized in that, The adhesive in step (3) is prepared by mixing modified siloxane, 4,4'-diaminodiphenyl ether, 3,3'-dihydroxybenzidine and N-methylpyrrolidone in a mass ratio of 2~3:8~10:3~5:160~170, stirring at 200~300r / min for 3~5min to obtain an amino mixture, adding hexafluorodianhydride at 0.43~0.47 times the molar amount of amino in the amino mixture, and continuing to stir for 100~140min.
7. A method for regenerating waste ternary lithium battery cathode material according to claim 6, characterized in that, The modified siloxane is prepared by uniformly mixing chloroplatinic acid and deionized water at a mass ratio of 1:80~100 to obtain an aqueous solution of chloroplatinic acid; mixing polysiloxane, deionized water and aqueous solution of chloroplatinic acid at a mass ratio of 8~10:20:0.4~0.6, stirring at 60~70℃ and 200~300r / min for 3~5min, adding an equimolar amount of 4-vinylphenylboronic acid of methyldimethoxysilane at a uniform rate over 8~10min, continuing stirring for 4~6h, removing the aqueous phase, washing with deionized water 3~5 times, and vacuum drying at -10~0℃ for 22~26h.
8. A method for regenerating waste ternary lithium battery cathode material according to claim 7, characterized in that, The polysiloxane is prepared by mixing 3-aminopropyldimethylmethoxysilane, dimethyldimethoxysilane, methyldimethoxysilane and deionized water in a mass ratio of 1:4~6:1:16~24, adjusting the pH to 5 with 0.1mol / L hydrochloric acid aqueous solution, stirring at 200~300r / min for 20~30min at room temperature, raising the temperature to 70~80℃ and stirring for 100~120min, removing the aqueous phase, washing with deionized water 3~5 times, and vacuum drying at -10~0℃ for 22~26h.
9. A method for regenerating waste ternary lithium battery cathode material according to claim 2, characterized in that, The carbon black mentioned in step (3) is 20nm conductive carbon black.