A method for regenerating waste ternary materials and regenerated ternary materials

Abstract

The present invention discloses a method for regenerating waste ternary materials and the regenerated ternary materials, belonging to the technical field of waste lithium-ion battery recycling. The waste ternary material regeneration method of the present invention achieves high-yield recovery of the ternary materials while ensuring the integrity of the material structure by utilizing mechanical and physical separation, liquid phase recovery, and heterogeneous flocculation and coating. This method not only effectively removes aluminum and binder impurities, reducing the amount of washing solvent used, but also simultaneously forms a point-surface / point-line / point-line-surface network coating structure on the material surface, enhancing the material's performance. The entire preparation process is simple, environmentally friendly, low-cost, and low-energy, making it suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling and regenerating waste lithium-ion batteries, and in particular to a method for regenerating waste ternary materials and a regenerated ternary material. Background Art

[0002] With the continuous development of new energy vehicles and the upgrading of electronic products, lithium-ion battery recycling has become an indispensable part of the entire battery industry chain. The recovery of nickel, cobalt, and manganese metals from spent lithium-ion batteries will generate considerable economic benefits. This is especially true for Co-Ni-Mn and Co-Ni-Al lithium-ion batteries, which have excellent safety. The recycling and regeneration of these ternary materials has important economic and environmental significance.

[0003] However, the waste ternary electrode materials contain aluminum foil, PVDF binder, carbon black conductive agent and other components, which seriously limit the repair and regeneration of waste ternary materials. The existing recycling technologies for waste ternary electrode materials mainly include: (1) recycling the ternary electrode materials through high-temperature heat treatment at 450~550℃, crushing and sorting, etc. However, during the high-temperature heat treatment process, the PVDF binder will crack and release a large amount of HF gas. The acidic gas HF easily reacts with the ternary material at high temperature to form metal fluoride, causing damage and failure of the ternary material during the recycling process. The subsequent repair can only be carried out by re-replenishing lithium and high-temperature sintering, resulting in high cost, high energy consumption and long process; (2) crushing and disassembling the ternary electrode, sorting, adding alkali and / or acid to leach nickel, cobalt and manganese ions, but the acid and alkali immersion uses a lot of reagents and a large amount, the process is complicated and recycling is difficult.

[0004] How to provide a method for regenerating waste ternary materials with high yield and ensuring the integrity of the material structure is an urgent problem to be solved in this field. Summary of the Invention

[0005] To address the aforementioned issues in the prior art, the present applicants have provided a method for regenerating waste ternary materials and a regenerated ternary material. This method utilizes mechanical and physical separation, liquid phase recovery, and heterogeneous flocculation and coating to achieve high-yield recovery of the ternary material while maintaining a well-maintained material structure. Furthermore, it eliminates the need for lithium supplementation and prolonged high-temperature sintering, resulting in low cost and energy consumption.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for regenerating waste ternary materials comprises the following steps:

[0008] S1. Crushing and sorting the waste ternary electrode to obtain primary ternary powder and primary aluminum powder; soaking the primary aluminum powder in an organic solvent, screening, filtering and eluting the sieve material to obtain a sieved liquid, an eluting liquid and a secondary aluminum powder;

[0009] S2, mixing the screening liquid, the washing liquid and the first-level ternary powder and soaking them, and screening them twice to obtain the third-level aluminum powder and the ternary slurry;

[0010] S3, mixing the carbon nanomaterial and the ternary slurry and stirring and dispersing them to obtain a dispersed slurry;

[0011] S4, adding the cationic polymer solution to the dispersed slurry and stirring for t time to obtain a flocculated slurry;

[0012] S5, filtering the flocculated slurry, washing the filter cake, dispersing it in an organic solvent, filtering it, and drying it;

[0013] S6. The dried material is heat-treated, sorted, and demagnetized to obtain a regenerated ternary material.

[0014] Preferably, in S1, the mass ratio of the primary aluminum powder to the organic solvent is 1:(1-2);

[0015] And / or, the organic solvent and the eluent used during elution both include at least one of NMP, DMF, and DMSO;

[0016] And / or, the purity of the organic solvent is ≥99.5%, and the water content is ≤1000ppm;

[0017] And / or, the soaking time is 5 to 8 hours;

[0018] And / or, the sieve aperture of the primary screening is 200-300 mesh;

[0019] And / or, the mass ratio of the primary aluminum powder to the eluting agent used during elution is 1:(2-3).

[0020] Preferably, in S2, the soaking time is 8 to 16 hours;

[0021] And / or, the mesh size during the secondary screening is 500-700 mesh.

[0022] Preferably, in S3, the amount of the carbon nanomaterial added is 1.5-3 wt % of the solid content in the ternary slurry in S2;

[0023] And / or, the carbon nanomaterial includes at least one of graphene oxide, oxidized carbon nanotubes, and carboxylated carbon nanotubes;

[0024] And / or, the stirring and dispersing speed is 5000-8000 rpm, and the time is 1-2 hours.

[0025] Preferably, the graphene oxide is a single layer or a multilayer;

[0026] And / or, the graphene oxide has a lateral size of ≥10 μm;

[0027] and / or, the oxidized carbon nanotubes are single-walled or multi-walled;

[0028] and / or, the carboxylated carbon nanotubes are single-walled or multi-walled;

[0029] and / or, the length of the oxidized carbon nanotubes is ≥10 μm;

[0030] And / or, the length of the carboxylated carbon nanotubes is ≥10 μm.

[0031] Preferably, in S4, the solute of the cationic polymer solution includes a polymer that can be dissolved in a strongly polar aprotic solvent; the solute includes at least one of modified polyacrylamine, polyamide, polyimide, polyamine, polyethyleneamine, and polyethyleneimine;

[0032] And / or, the solvent of the cationic polymer solution includes at least one of NMP, DMF, and DMSO;

[0033] and / or, the solid content of the cationic polymer solution is 5 to 10 wt %;

[0034] And / or, the mass ratio of solute to carbon nanomaterial in the cationic polymer solution is 1:(0.8-1.2).

[0035] Preferably, in S4, the cationic polymer solution is added to the dispersed slurry while stirring, the adding time is 30 to 60 minutes, and the stirring speed is 1000 to 2000 rpm;

[0036] And / or, the stirring time t is 20 to 30 minutes.

[0037] Preferably, in S5, the ratio of the total mass of the organic solvent used for washing and dispersing to the mass of the solid in the ternary slurry in S2 is (1.5-2):1;

[0038] And / or, the organic solvent comprises at least one of NMP, DMF, and DMSO;

[0039] And / or, the drying temperature is 105-115°C.

[0040] Preferably, in S6, the heat treatment temperature is 600-700° C., and the heat treatment time is 2-5 hours;

[0041] And / or, the heat treatment is performed in a protective atmosphere, preferably, the protective atmosphere comprises at least one of argon or nitrogen.

[0042] The present invention also provides a recycled ternary material, which is prepared by the above-mentioned method for recycling waste ternary materials.

[0043] The beneficial technical effects of the present invention are:

[0044] (1) The method for regenerating waste ternary materials of the present invention achieves high-yield recovery of ternary materials while ensuring the integrity of the material structure by adopting mechanical and physical separation, liquid phase recovery, and heterogeneous flocculation coating. At the same time, the physical and mechanical separation combined with liquid phase recovery can reduce the generation of micron-sized aluminum chips, and aluminum impurities can be effectively removed through precise screening without the need for strong alkali washing. The preparation process is simple, environmentally friendly, and suitable for industrial production.

[0045] (2) The regeneration method of waste ternary materials of the present invention solves the problem that the PVDF binder in the waste ternary materials cannot be removed efficiently, quickly, non-destructively and at low cost through the scheme of heterogeneous flocculation coating. Moreover, while removing the binder, it forms a point-surface / point-line / point-line-surface network carbon coating structure with the original Super P conductive agent in the material. The network coating structure can avoid side reactions on the surface of the material, and can significantly improve the conductivity of the material, reducing the amount of conductive agent used in the subsequent electrode manufacturing process; at the same time, there is no need for lithium supplementation and long-term high-temperature sintering process, which is low in cost and energy consumption. DETAILED DESCRIPTION

[0046] The present invention will be described in detail below with reference to the embodiments.

[0047] The first aspect of the present invention provides a method for regenerating waste ternary materials, comprising the following steps:

[0048] S1. Crushing and sorting the waste ternary electrode to obtain primary ternary powder and primary aluminum powder; soaking the primary aluminum powder in an organic solvent, screening, filtering and eluting the sieve material to obtain a sieved liquid, an eluting liquid and a secondary aluminum powder;

[0049] S2, mixing the screening liquid, the washing liquid and the first-level ternary powder and soaking them, and screening them twice to obtain the third-level aluminum powder and the ternary slurry;

[0050] S3, mixing the carbon nanomaterial and the ternary slurry and stirring and dispersing them to obtain a dispersed slurry;

[0051] S4, adding the cationic polymer solution to the dispersed slurry and stirring for t time to obtain a flocculated slurry;

[0052] S5, filtering the flocculated slurry, washing the filter cake, dispersing it in an organic solvent, filtering it, and drying it;

[0053] S6. The dried material is heat-treated, sorted, and demagnetized to obtain a regenerated ternary material.

[0054] In addition to the ternary materials, the waste ternary electrode materials also contain aluminum foil, PVDF binder, carbon black conductive agent and other components. The method of the present invention combines physical stripping and liquid phase stripping to recover the ternary materials without loss and at a high yield, and remove aluminum impurities through precise screening.

[0055] Understandably, when scrap ternary electrode materials are stripped and recycled using chemical or high-temperature methods, the aluminum foil partially dissolves and denatures, becoming brittle and prone to producing excessive amounts of tiny aluminum chips. However, the present invention utilizes purely physical collision and friction separation, combined with liquid-phase stripping, to ensure that the aluminum foil maintains excellent toughness and ductility. This reduces the generation of tiny aluminum chips while producing aluminum powder, facilitating subsequent aluminum removal and sorting, while also reducing aluminum impurities in the recycled ternary material.

[0056] The ternary material undergoing liquid-phase exfoliation forms a viscous solution due to the dissolution of the ultra-high molecular weight PVDF binder. This highly viscous solution is extremely difficult to separate from the solid and liquid, requiring high dilution and multiple washings to separate and extract the ternary material. However, the present invention adds carbon nanomaterials and cationic polymers, allowing the cationic polymers to combine with the negatively charged carbon nanomaterials to form flocs that encapsulate the ternary material. This promotes the aggregation of the ternary material, reduces viscosity barriers in the solution, and facilitates rapid sedimentation and filtration of solid particles during separation.

[0057] This heterogeneous flocculation coating solution not only solves the problem of the inability to efficiently, quickly, and non-destructively remove the PVDF binder from waste ternary materials, but also forms a network-like carbon coating on the material surface while removing the binder, enabling rapid and low-cost regeneration of waste ternary materials. Furthermore, the carbon black conductive agent in the waste ternary electrode material does not need to be removed. Instead, it can form a stable point-surface / point-line / point-line-surface network-like carbon coating structure with carbon nanomaterials and cationic polymers. This coating structure can prevent the surface of the positive electrode material from contacting trace moisture and HF in the battery, reducing side reactions, significantly improving the conductivity of the positive electrode material, and reducing the amount of conductive agent used in the subsequent electrode manufacturing process.

[0058] In some embodiments, in S1, the mass ratio of the primary aluminum powder to the organic solvent is 1:(1-2), including but not limited to 1:1, 1:1.5, and 1:2.

[0059] In some embodiments, in S1, the organic solvent and the eluent used for elution both include at least one of NMP, DMF, and DMSO.

[0060] In some embodiments, in S1, the purity of the organic solvent is ≥99.5%, and the water content is ≤1000 ppm.

[0061] In some embodiments, in S1, the soaking time is 5 to 8 hours, including but not limited to 5 hours, 6 hours, 7 hours, and 8 hours.

[0062] In some embodiments, in S1, the aperture of the sieve for the primary screening is 200-300 mesh, including but not limited to 200 mesh, 250 mesh, and 300 mesh.

[0063] In some embodiments, in S1, the mass ratio of the primary aluminum powder to the eluent used in elution is 1:(2-3), including but not limited to 1:2, 1:2.5, and 1:3.

[0064] In some embodiments, in S2, the soaking time is 8 to 16 hours, including but not limited to 8 hours, 10 hours, 12 hours, 14 hours, and 16 hours.

[0065] In some embodiments, in S2, the aperture of the sieve during the secondary screening is 500-700 mesh, including but not limited to 500 mesh, 600 mesh, and 700 mesh.

[0066] It is understandable that the first-level aluminum powder and the second-level aluminum powder will contain unseparated ternary powder, so they need to be screened multiple times to improve the yield of the ternary material.

[0067] In some embodiments, in S3, the amount of the carbon nanomaterial added is 1.5-3 wt% of the solid content in the ternary slurry in S2, including but not limited to 1.5 wt%, 2 wt%, 2.5 wt%, and 3 wt%.

[0068] In some embodiments, in S3, the carbon nanomaterial includes at least one of graphene oxide, oxidized carbon nanotubes, and carboxylated carbon nanotubes.

[0069] In some embodiments, in S3, the stirring and dispersing speed is 5000-8000 rpm, including but not limited to 5000 rpm, 6000 rpm, 7000 rpm, and 8000 rpm, and the time is 1-2 h, including but not limited to 1 h, 1.5 h, and 2 h.

[0070] In some embodiments, in S3, the graphene oxide is a single layer or multiple layers.

[0071] In some embodiments, in S3, the lateral size of the graphene oxide is ≥10 μm.

[0072] In some embodiments, in S3, the oxidized carbon nanotubes are single-walled or multi-walled.

[0073] In some embodiments, in S3, the carboxylated carbon nanotubes are single-walled or multi-walled.

[0074] In some embodiments, in S3, the length of the oxidized carbon nanotubes is ≥ 10 μm.

[0075] In some embodiments, in S3, the carboxylated carbon nanotubes have a length of ≥10 μm.

[0076] If the size of the carbon nanomaterial is too small, it will lead to poor sedimentation effect of the ternary material during the solid-liquid separation process; it will also lead to poor continuity of the carbon network structure formed by the coating, thereby affecting the performance of the positive electrode material.

[0077] In some embodiments, in S4, the solute of the cationic polymer solution includes a polymer that can be dissolved in a strongly polar aprotic solvent, including but not limited to at least one of modified polyacrylamine, polyamide, polyimide, polyamine, polyethyleneamine, and polyethyleneimine.

[0078] In some embodiments, in S4, the solvent of the cationic polymer solution includes at least one of NMP, DMF, and DMSO.

[0079] In some embodiments, in S4, the solid content of the cationic polymer solution is 5-10 wt%, including but not limited to 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, and 10 wt%.

[0080] In some embodiments, in S4, the mass ratio of the solute in the cationic polymer solution to the carbon nanomaterial is 1:(0.8-1.2), including but not limited to 1:0.8, 1:1.0, and 1:1.2.

[0081] It can be understood that during the stirring process, the dispersed carbon nanomaterials, upon encountering the cationic polymer, can combine on the surface of the ternary material and form a network-like coating structure.

[0082] The addition amount of carbon nanomaterials and cationic polymer solutions should be appropriate. If the addition amount of carbon nanomaterials is too low, it will lead to poor sedimentation effect and poor coating effect of the ternary material; if the addition amount of carbon nanomaterials is too high, it will lead to excessive coating, which will cause the capacity of the positive electrode material to decrease; if the addition amount of cationic polymer solution is too low or too high, it will cause poor sedimentation effect, which will lead to difficulties in solid-liquid separation and affect the recycling rate of the regenerated ternary material.

[0083] In some embodiments, in S4, the cationic polymer solution is added to the dispersed slurry while stirring, and the adding time is 30 to 60 minutes, including but not limited to 30 minutes, 40 minutes, 50 minutes, and 60 minutes; the stirring speed is 1000 to 2000 rpm, including but not limited to 1000 rpm, 1500 rpm, and 2000 rpm.

[0084] In some embodiments, in S4, the stirring time t is 20 to 30 min, including but not limited to 20 min, 25 min, and 30 min.

[0085] In some embodiments, in S5, the ratio of the total mass of the organic solvent used for washing and dispersing to the mass of the solids in the ternary slurry in S2 is (1.5~2):1; including but not limited to 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, and 2.0:1.

[0086] In some embodiments, in S5, the organic solvent includes at least one of NMP, DMF, and DMSO.

[0087] In some embodiments, in S5, the drying temperature is 105-115°C, including but not limited to 105°C, 110°C, and 115°C.

[0088] In some embodiments, in S6, the heat treatment temperature is 600-700°C, including but not limited to 600°C, 650°C, and 700°C, and the heat treatment time is 2-5h, including but not limited to 2h, 3h, 4h, and 5h.

[0089] During the heat treatment process, the oxygen-containing functional groups in the carbon nanomaterial dissolve, forming a network-like carbon coating structure with the existing carbon black conductive agent in the material. The heat treatment temperature should not be too high or too low. Too high will cause the ternary material to melt, while too low will result in incomplete carbonization and coating.

[0090] In some embodiments, in S6, the heat treatment is performed in a protective atmosphere. Preferably, the protective atmosphere includes at least one of argon or nitrogen.

[0091] It is understandable that in S6, the purpose of the demagnetization is to remove magnetic metal impurities such as iron and nickel in the ternary material, avoid internal short circuit of the battery, and improve battery safety.

[0092] The second aspect of the present invention provides a recycled ternary material, which is produced by the recycling method of waste ternary materials described in the first aspect.

[0093] Example 1

[0094] A method for regenerating waste ternary materials comprises the following steps:

[0095] S1. Cut and crush 200 kg of waste 622 type ternary electrodes (aluminum current collector content 10 wt%), and sort them according to weight and particle size to obtain 105 kg of first-level ternary powder and 95 kg of first-level aluminum powder. Put the first-level aluminum powder into a reactor, add 171 kg of NMP solution, stir and soak for 6 hours, then sieve through a 250-mesh vibrating screen, and rinse the sieve with 273 kg of NMP to obtain sieved liquid, eluted liquid and second-level aluminum powder.

[0096] S2. The sieved liquid, elution liquid and first-level ternary powder in step S1 were transferred to a reactor for mixing. After stirring and soaking for 11 hours, they were sieved through a 600-mesh ultrasonic vibration screen to obtain third-level aluminum powder and 618 kg of ternary slurry. The solid content of the slurry was tested to be 28.7%, containing 177 kg of ternary material. After calculation, the yield of the ternary material was 98.3%.

[0097] S3. First, add 5.2 kg of graphene oxide with a lateral size greater than 10 μm into the reactor, and then add the ternary slurry. Stir and disperse at 6000 rpm for 1.5 hours to obtain a dispersed slurry.

[0098] S4. Add 50 kg of a 10 wt % NMP solution of polyethyleneimine to the dispersed slurry, and complete the addition within 40 minutes at a rotation speed of 1500 rpm. After the addition is completed, continue stirring for 20 minutes to obtain a flocculated slurry.

[0099] S5. After filtering the flocculated slurry, rinse it with 70 kg NMP, disperse the filter cake into 200 kg NMP, filter it again, and flash dry it at 110°C.

[0100] S6. The dried material was placed in a roller kiln and heat treated at 650°C in nitrogen for 3 hours. The material was sorted according to particle size and demagnetized to obtain 167 kg of recycled ternary material with a recycling rate of 94.3%.

[0101] In the above step S2: yield = (mass of ternary material recovered from the positive electrode sheet / theoretical mass of ternary material in the positive electrode sheet) × 100%;

[0102] In the above step S6: regeneration recovery rate = (mass of regenerated ternary material / mass of ternary material recovered from the positive electrode sheet) × 100%.

[0103] Example 2

[0104] A method for regenerating waste ternary materials comprises the following steps:

[0105] S1. Cut and crush 155 kg of waste 523 type ternary electrodes (aluminum current collector content 10 wt%), and sort them according to weight and particle size to obtain 85 kg of first-level ternary powder and 70 kg of first-level aluminum powder. Put the first-level aluminum powder into a reactor, add 70 kg of DMF solution, stir and soak for 5 hours, then sieve through a 300-mesh vibrating screen, and wash the sieve with 210 kg of DMF to obtain sieved liquid, eluted liquid and second-level aluminum powder.

[0106] S2. The sieved liquid, elution liquid and first-level ternary powder in step S1 were transferred to a reactor for mixing. After stirring and soaking for 16 hours, they were sieved through a 500-mesh ultrasonic vibration screen to obtain third-level aluminum powder and 410 kg of ternary slurry. The solid content of the slurry was tested to be 33.5%, containing 137 kg of ternary material. After calculation, the yield of the ternary material was 98.2%.

[0107] S3. First, add 2.7 kg of oxidized carbon nanotubes with a length greater than 10 μm into the reactor, and then add the ternary slurry. Stir and disperse at 5000 rpm for 2.0 h to obtain a dispersed slurry.

[0108] S4. Add 55 kg of a 5 wt % polyamide DMF solution to the dispersed slurry and complete the addition within 60 min at a rotation speed of 1000 rpm. After the addition is completed, continue stirring for 20 min to obtain a flocculated slurry.

[0109] S5. After filtering the flocculated slurry, rinse it with 50 kg of DMF, disperse the filter cake into 185 kg of DMF, filter it again, and then flash dry it at 105°C.

[0110] S6. The dried material was placed in a roller kiln and heat treated at 700°C in nitrogen for 3 hours. The material was sorted according to particle size and demagnetized to obtain 130 kg of recycled ternary material with a recycling rate of 94.8%.

[0111] Example 3

[0112] A method for regenerating waste ternary materials comprises the following steps:

[0113] S1. Cut and crush 320 kg of waste 811 type ternary electrodes (aluminum current collector content 8 wt%), and sort them according to weight and particle size to obtain 162 kg of first-level ternary powder and 158 kg of first-level aluminum powder. Put the first-level aluminum powder into a reactor, add 316 kg of DMSO solution, stir and soak for 5 hours, then sieve through a 250-mesh vibrating screen, and rinse the sieve with 316 kg of DMSO to obtain sieved liquid, elution liquid and second-level aluminum powder.

[0114] S2. The sieved liquid, elution liquid and first-level ternary powder in step S1 were transferred to a reactor for mixing. After stirring and soaking for 8 hours, the mixture was sieved through a 700-mesh ultrasonic vibration sieve to obtain third-level aluminum powder and 905 kg of ternary slurry. The solid content of the slurry was tested to be 31.9%, containing 289 kg of ternary material. The yield of the ternary material was calculated to be 98.1%.

[0115] S3. First, add 5.5 kg of carboxylated carbon nanotubes with a length greater than 10 μm into the reactor, and then add the ternary slurry. Stir and disperse at 8000 rpm for 1.0 h to obtain a dispersed slurry.

[0116] S4. Add 91 kg of a 6 wt % DMSO solution of butyl acrylate copolymer-modified polyacrylamide to the dispersed slurry, and complete the addition within 30 minutes at a rotation speed of 2000 rpm. After the addition is completed, continue stirring for 30 minutes to obtain a flocculated slurry.

[0117] S5. After filtering the flocculated slurry, rinse it with 120 kg of DMSO, disperse the filter cake into 330 kg of DMSO, filter it again, and flash dry it at 110°C.

[0118] S6. The dried material was placed in a roller kiln and heat treated at 600°C in nitrogen for 3 hours. The material was sorted according to particle size and demagnetized to obtain 273 kg of recycled ternary material with a recycling rate of 94.5%.

[0119] Comparative Example 1

[0120] 150 kg of waste 622 type ternary positive electrode sheets (aluminum current collector content 10 wt%) were heat treated at 450 ° C in air for 1.5 hours, and then mechanically stripped and sorted to obtain 131 kg of ternary black powder; the ternary black powder was placed in 1 mol / L sodium hydroxide to control the solid content to 20%, reacted for 30-60 minutes, and then washed with water to a pH of 7-8 to remove aluminum impurities in the ternary black powder. After drying, lithium carbonate powder was added according to the amount of lithium loss in the material. After mixing, the mixture was sintered in oxygen at 800 ° C for 10 hours. The sintered product was crushed and sorted to obtain 120 kg of recycled ternary material.

[0121] Comparative Example 2

[0122] The method is basically the same as Example 1, except that the amount of graphene oxide added in S3 is 10.0 kg.

[0123] Comparative Example 3

[0124] The process is basically the same as Example 1, except that the amount of 10 wt % NMP solution of polyethyleneimine added in S4 is 20 kg.

[0125] Comparative Example 4

[0126] It is basically the same as Example 1, except that the lateral size of the graphene oxide used in S3 is about 3 microns.

[0127] Comparative Example 5

[0128] Basically the same as Example 1, except that the heat treatment temperature in S6 is 500°C.

[0129] Comparative Example 6

[0130] Basically the same as Example 1, except that the heat treatment temperature in S6 is 800°C.

[0131] Test example:

[0132] (1) Material yield

[0133] The aluminum impurity content in the above examples and some comparative examples was detected by inductively coupled plasma atomic emission spectroscopy (ICP). The results of the yield of the ternary material, the recycling rate of the regenerated ternary material and the aluminum impurity content are shown in Table 1.

[0134] Table 1: Yield table of Examples and Comparative Examples

[0135]

[0136] It can be seen from Table 1 that the method of the present invention can recover ternary materials from waste ternary materials with high yield, realize recycling, and the recycling rate is high, and reduce the content of aluminum impurities in the recycled ternary materials.

[0137] (2) Battery electrochemical performance test

[0138] The recycled ternary materials obtained in the above examples and comparative examples were assembled into batteries according to the following steps, and the following electrochemical performance tests were performed. The test results are shown in Table 2.

[0139] The present invention mixes the prepared recycled ternary material with a binder and a conductive agent, then prepares the mixture into a pulp, coats it, rolls it, and cuts it. A lithium sheet is then used as a counter electrode to prepare a button cell. The cell is cycled two times at a 0.1C rate with a voltage range of 3.0 to 4.3V, and its gram capacity is measured. The capacity retention rate is tested by mixing the prepared recycled ternary material with a binder and a conductive agent, then preparing the mixture into a pulp, coats it, rolls it, and cuts it. A single-cell cell is then prepared using a graphite electrode as a counter electrode. The cell is cycled 500 times at a 1C rate at room temperature with a voltage range of 3.0 to 4.3V.

[0140] Table 2: Performance test table of examples and comparative examples

[0141]

[0142] By comparing Examples 1 to 3 with Comparative Example 1, and combining Tables 1 and 2, it can be seen that the regeneration method of waste ternary materials of the present invention has the advantages of high yield and high recycling rate, and the electrochemical properties of the obtained regenerated ternary materials are excellent, which shows that the material structure can be kept intact when the method of the present invention is used for recycling; in addition, the method does not require lithium supplementation and long-term high-temperature sintering, and has low cost and low energy consumption.

[0143] Comparing Example 1 with Comparative Example 2, it can be seen from Table 2 that when the amount of carbon nanomaterial added is too high, the capacity of the regenerated ternary material will decrease. The reason may be that the excessive addition amount leads to excessive coating amount, thus affecting the capacity.

[0144] Comparing Example 1 with Comparative Example 3, and combining Tables 1 and 2, it can be seen that when the amount of cationic polymer solution added is too low, it has little effect on the electrochemical properties of the regenerated ternary material, and mainly affects the recycling rate of the material. The reason may be that when the amount of cationic polymer solution added is too low, the sedimentation effect is poor, thereby affecting the utilization rate of the renewable material.

[0145] Comparing Example 1 with Comparative Example 4, and combining Tables 1 and 2, it can be seen that when the size of the carbon nanomaterial is too small, it will have a negative impact on the recycling rate and electrochemical performance of the regenerated ternary material. The reasons may be: too small a size will lead to poor material sedimentation effect and reduced material recycling rate. In addition, it will also lead to poor continuity of the carbon network structure formed by the coating, thereby affecting the electrochemical performance.

[0146] Comparing Example 1 with Comparative Examples 5 and 6, and combining Table 1 and Table 2, it can be seen that if the heat treatment temperature is too low or too high, it will have a negative impact on the recycling rate and electrochemical performance of the regenerated ternary material. The reasons may be: too high a heat treatment temperature will cause the regenerated ternary material to melt and agglomerate, while too low a heat treatment temperature will lead to incomplete carbonization coating, thereby affecting the electrochemical performance.

[0147] In summary, the regeneration method of waste ternary materials of the present invention can recycle ternary materials with a high yield and ensure the integrity of the material structure, so that it has good electrochemical properties. At the same time, during recycling, there is no need for multiple washing with the help of strong alkali, etc., which reduces the amount of detergent used, and there is no need for lithium supplementation and long-term high-temperature sintering, with low cost and low energy consumption.

[0148] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A method for regenerating waste ternary materials, characterized in that: The following steps are involved: S1. Crushing and sorting the waste ternary electrode to obtain primary ternary powder and primary aluminum powder; soaking the primary aluminum powder in an organic solvent, screening, filtering and eluting the sieve material to obtain a sieved liquid, an eluting liquid and a secondary aluminum powder; S2, mixing the screening liquid, the washing liquid and the first-level ternary powder and soaking them, and screening them twice to obtain the third-level aluminum powder and the ternary slurry; S3, mixing the carbon nanomaterial and the ternary slurry and stirring and dispersing them to obtain a dispersed slurry; S4, adding the cationic polymer solution to the dispersed slurry and stirring for t time to obtain a flocculated slurry; S5, filtering the flocculated slurry, washing the filter cake, dispersing it in an organic solvent, filtering it, and drying it; S6. heat-treating, sorting, and demagnetizing the dried material to obtain a regenerated ternary material having a network-like carbon coating structure; the network-like carbon coating structure is formed by the carbon nanomaterial and the carbon black conductive agent in the ternary slurry; The carbon nanomaterial includes at least one of graphene oxide, oxidized carbon nanotubes, and carboxylated carbon nanotubes; The graphene oxide has a lateral size of ≥10 μm; The length of the oxidized carbon nanotubes is ≥10 μm; The length of the carboxylated carbon nanotubes is ≥10 μm; In S4, the solute of the cationic polymer solution includes a polymer that can be dissolved in a strongly polar aprotic solvent; the solute includes at least one of modified polyacrylamine, polyamide, polyimide, polyethyleneamine, and polyethyleneimine; The solvent of the cationic polymer solution includes at least one of NMP, DMF, and DMSO; The mass ratio of the solute in the cationic polymer solution to the carbon nanomaterial is 1:(0.8-1.2); In S6, the heat treatment temperature is 600-700°C.

2. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S1, the mass ratio of the primary aluminum powder to the organic solvent is 1:(1-2); And / or, the organic solvent and the eluent used during elution both include at least one of NMP, DMF, and DMSO; And / or, the purity of the organic solvent is ≥99.5%, and the water content is ≤1000ppm; And / or, the soaking time is 5 to 8 hours; And / or, the sieve aperture of the primary screening is 200-300 mesh; And / or, the mass ratio of the primary aluminum powder to the eluting agent used during elution is 1:(2-3).

3. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S2, the soaking time is 8 to 16 hours; And / or, the mesh size during the secondary screening is 500-700 mesh.

4. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S3, the amount of the carbon nanomaterial added is 1.5-3 wt % of the solid content in the ternary slurry in S2; And / or, the stirring and dispersing speed is 5000-8000 rpm, and the time is 1-2 hours.

5. The method for regenerating waste ternary materials according to claim 4, characterized in that: The graphene oxide is a single layer or multiple layers; and / or, the oxidized carbon nanotubes are single-walled or multi-walled; And / or, the carboxylated carbon nanotubes are single-walled or multi-walled.

6. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S4, the solid content of the cationic polymer solution is 5-10 wt%.

7. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S4, the cationic polymer solution is added to the dispersed slurry while stirring, the addition time is 30 to 60 minutes, and the stirring speed is 1000 to 2000 rpm; And / or, the stirring time t is 20 to 30 minutes.

8. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S5, the ratio of the total mass of the organic solvent used for washing and dispersing to the mass of the solid in the ternary slurry in S2 is (1.5-2):1; And / or, the organic solvent comprises at least one of NMP, DMF, and DMSO; And / or, the drying temperature is 105-115°C.

9. The method for regenerating waste ternary materials according to claim 1, characterized in that: In S6, the heat treatment time is 2 to 5 h; And / or, the heat treatment is performed in a protective atmosphere, which includes at least one of argon or nitrogen.

10. A recycled ternary material, characterized in that: It is prepared by the recycling method of waste ternary materials according to any one of claims 1 to 9.

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