A method for recycling waste ternary lithium batteries

Abstract

The present invention provides a method for recycling waste ternary lithium batteries, and belongs to the technical field of recycling waste electrode materials. The present invention dissolves PVDF binder by forming a mixed solvent of N,N-dimethylacetamide and triethylamine, and then prepares a modified quaternary ammonium salt based on the mixed solvent, and applies it to a low eutectic solvent, and simultaneously uses the quaternary ammonium salt to obtain a fluorine-containing nickel-cobalt-manganese salt, so that the positive electrode regeneration material recycled from the waste ternary lithium battery exhibits excellent electrochemical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling waste electrode materials, and in particular relates to a method for recycling waste ternary lithium batteries. Background Art

[0002] Lithium-ion batteries have excellent characteristics such as high capacity density, high output voltage, and long service life. They are widely used in portable electronic products, energy storage, and new energy vehicles. In recent years, the rapid development of the electric vehicle industry has stimulated the explosive growth of lithium-ion battery use. Generally, the service life of lithium-ion batteries is 5-8 years, so the retirement wave of waste lithium-ion batteries will gradually come in recent years. Waste ternary lithium-ion batteries contain rich valuable metal substances, such as lithium, nickel, cobalt, manganese, etc. These precious metals are unevenly distributed and scarce in countries around the world. Compared with directly mined metal minerals, the precious metals recovered from waste ternary lithium-ion batteries are of higher quality. Therefore, recycling waste ternary lithium-ion batteries has a high economic value, and it can also reduce dependence on precious metal mineral resources to a certain extent.

[0003] A Chinese patent (publication number CN118398941A) discloses a method for recycling waste ternary lithium battery positive electrode materials and product resource utilization, which uses a recyclable acid solution to leach metals from waste ternary lithium battery positive electrode materials, and then effectively recovers each metal through different solvents, and can utilize the by-products generated in the process to achieve high-value resource utilization of waste ternary lithium battery positive electrode materials. However, the patent does not solve the problem that the existing technology has a low solvent reuse rate and cannot efficiently leach metals when recycling waste ternary lithium batteries, and the electrochemical performance of the positive electrode recycled materials recovered by introducing nickel, cobalt and manganese salts needs to be improved.

[0004] Therefore, there is an urgent need for a method for recycling waste ternary lithium batteries. By reusing the solvent, the solvent can play a role in both the pretreatment and leaching treatment stages, and modified materials can be introduced during the regeneration process to improve the electrochemical properties of the recovered positive electrode regenerated materials. Summary of the invention

[0005] The purpose of the present invention is to provide a method for recycling waste ternary lithium batteries, wherein a PVDF binder is dissolved by a mixed solvent composed of N,N-dimethylacetamide and triethylamine, and then a modified quaternary ammonium salt is prepared based on the mixed solvent, and the modified quaternary ammonium salt is applied to a low eutectic solvent, and a fluorine-containing nickel-cobalt-manganese salt is obtained by using the quaternary ammonium salt, so that the positive electrode regeneration material recovered from the waste ternary lithium batteries exhibits excellent electrochemical properties.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for recycling waste ternary lithium batteries comprises the following steps:

[0008] Step S1: pre-treating the waste ternary lithium battery to obtain a ternary lithium battery positive electrode active material; placing 10 to 20 parts of the positive electrode active material in 200 to 220 parts of a mixed solvent, ultrasonically treating the waste battery, drying the waste battery, and ball milling the waste battery to obtain a pre-treated ternary lithium battery positive electrode material powder, while retaining the ultrasonically treated mixed solvent;

[0009] Step S2: by weight, 12 to 14 parts of 1,6-hexanediamine are added to 30 to 40 parts of chloroform, stirred for 10 to 20 minutes, and then 16 to 18 parts of glycidol are added dropwise, reacted at 60 to 70° C. for 4 to 6 hours, and the solvent is evaporated at room temperature using a rotary evaporator to obtain a first intermediate; 40 to 50 parts of the first intermediate are added to 200 to 220 parts of the mixed solvent treated with ultrasound in step S1, stirred for 10 to 20 minutes, and then stirred for 10 to 20 minutes. min, then add 16 to 20 parts of hexafluoropropylene oxide trimer to react for 8 to 10 hours, extract and wash with hydrochloric acid with a molar concentration of 0.1 mol / L, take the lower layer, and then wash it with deionized water for 3 times to obtain a second intermediate; add 7 to 9 parts of the second intermediate and 2 to 4 parts of potassium carbonate to 15 to 20 parts of anhydrous ethanol, stir for 10 to 20 minutes, then add 2 to 4 parts of iodomethane, react at room temperature for 6 to 8 hours, filter, and rotary evaporate to obtain a modified quaternary ammonium salt;

[0010] Step S3: adding 20 to 25 parts of the modified quaternary ammonium salt described in step S2 to 80 to 100 parts of propylene glycol by weight, stirring at 200 to 300 r / min for 1 to 2 hours, then adding 20 to 30 parts of an acid compound, reacting at 50 to 60° C. for 30 to 40 minutes to obtain a low eutectic solvent;

[0011] Step S4: adding 10 to 12 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 200 to 220 parts of the low eutectic solvent in step S3, and then stirring to react, and filtering after the reaction is completed to obtain a metal ion leachate;

[0012] Step S5: Add 10 to 15 parts by weight of fluorine-containing nickel cobalt manganese salt to 200 to 220 parts of the metal ion leachate of step S4, stir for 20 to 30 minutes to obtain a precursor solution, heat the precursor solution for reaction, and after the reaction is completed, filter, wash and dry in sequence to obtain a positive electrode recycled material recovered from a waste ternary lithium battery.

[0013] By using a mixed solvent composed of N,N-dimethylacetamide and triethylamine, the PVDF and other binders of the waste ternary lithium battery can be dissolved, thereby separating the positive electrode active material from the aluminum foil; in addition, ultrasonic-assisted treatment is used to induce the material to produce holes, thereby accelerating the dissolution and separation, and the obtained waste material morphology shows good dispersibility, which is beneficial to improving the subsequent leaching effect, thereby affecting the performance of the final recycled material.

[0014] As a preferred solution, the pre-treatment in step S1 includes a discharge treatment and a disassembly treatment.

[0015] As a preferred solution, the mixed solvent in step S1 is N,N-dimethylacetamide and triethylamine; the mass ratio of N,N-dimethylacetamide to triethylamine is (9-10):1.

[0016] As a preferred solution, the ultrasonic temperature of the ultrasonic treatment in step S1 is 60-70° C., the ultrasonic power is 200-220 W, and the ultrasonic time is 1-2 h.

[0017] As a preferred solution, the acid compound in step S3 is selected from any one of oxalic acid, citric acid and malic acid, or a combination of at least two of them.

[0018] The mixed solvent in the pretreatment step is reused to synthesize modified quaternary ammonium salts, and the modified quaternary ammonium salts are used as hydrogen bond acceptors for low eutectic solvents. Non-toxic green organic acids such as oxalic acid and citric acid are used as hydrogen bond donors to form hydrogen bonds with the modified quaternary ammonium salts to destroy the chemical bonds between metals and oxygen, thereby obtaining a leachate containing valuable metals, which reduces environmental pollution while ensuring the metal leaching efficiency of the low eutectic solvent, thereby improving the performance of the final recycled materials.

[0019] As a preferred solution, the stirring speed of the stirring reaction in step S4 is 100-200 r / min, the reaction temperature is 80-90° C., and the reaction time is 1-2 h.

[0020] As a preferred solution, the reaction temperature of the heating reaction in step S5 is 120-125° C., and the reaction time is 18-20 h.

[0021] As a preferred scheme, the preparation method of the fluorine-containing nickel-cobalt-manganese salt described in step S5 comprises: adding 2.2 to 2.5 parts of nickel sulfate, 0.2 to 0.4 parts of cobalt sulfate and 0.1 to 0.3 parts of manganese sulfate to 80 to 100 parts of deionized water, stirring for 10 to 20 minutes, and then adding 0.4 to 0.6 parts of urea and 0.5 to 0.8 parts of the modified quaternary ammonium salt described in step S2, stirring for 20 to 30 minutes; then adding 10 to 12 parts of tetrahydrofuran for hydrothermal reaction, centrifuging after the hydrothermal reaction is completed, removing the solid phase, washing with deionized water, and vacuum drying to obtain the fluorine-containing nickel-cobalt-manganese salt.

[0022] As a preferred solution, the reaction temperature of the hydrothermal reaction is 110-120° C., and the reaction time is 10-12 h.

[0023] Fluorine-containing nickel-cobalt-manganese salts can replenish the nickel, cobalt and manganese elements required for positive electrode regeneration materials at one time. Fluorine is also introduced through modified quaternary ammonium salts. The fluorine element works together with nickel, cobalt and manganese elements to make the positive electrode regeneration materials recovered from waste ternary lithium batteries exhibit excellent electrochemical properties.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0025] 1. The present invention uses N,N-dimethylacetamide and triethylamine to form a mixed solvent, which can dissolve the PVDF and other binders of the waste ternary lithium battery, thereby separating the positive electrode active material from the aluminum foil; in addition, ultrasonic-assisted treatment is used to induce the material to generate holes to accelerate the dissolution and separation, and the obtained waste morphology shows good dispersibility, which is conducive to improving the subsequent leaching effect, thereby affecting the performance of the final recycled material.

[0026] 2. The present invention reuses the mixed solvent in the pretreatment step for synthesizing modified quaternary ammonium salts, and uses the modified quaternary ammonium salts as hydrogen bond acceptors for low eutectic solvents; and uses non-toxic green organic acids such as oxalic acid and citric acid as hydrogen bond donors to form hydrogen bonds with the modified quaternary ammonium salts to destroy the chemical bonds between metals and oxygen, thereby obtaining a leachate containing valuable metals, which reduces environmental pollution while ensuring the metal leaching efficiency of the low eutectic solvent, thereby improving the performance of the final recycled material.

[0027] 3. The fluorine-containing nickel-cobalt-manganese salt of the present invention can replenish the nickel, cobalt and manganese elements required for the positive electrode regeneration material at one time, and also introduces the fluorine element by modifying the quaternary ammonium salt. The fluorine element cooperates with the nickel, cobalt and manganese elements to make the positive electrode regeneration material recovered from the waste ternary lithium battery show excellent electrochemical properties. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The sources of some components in the embodiments and comparative examples are as follows:

[0030] N,N-dimethylacetamide, CAS No. 127-19-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0031] Triethylamine, CAS No. 121-44-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0032] 1,6-Hexanediamine, CAS No. 124-09-4, purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0033] Chloroform, CAS No. 67-66-3, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0034] Glycidol, CAS No. 556-52-5, was purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0035] Hexafluoropropylene oxide trimer, product number A2218271, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0036] Hydrochloric acid, CAS No. 7647-01-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0037] Potassium carbonate, CAS No. 584-08-7, purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0038] Anhydrous ethanol, CAS No. 64-17-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0039] Iodomethane, CAS No. 74-88-4, was purchased from Nanjing Huangtai Pharmaceutical Technology Co., Ltd.;

[0040] Glycerol, CAS No. 56-81-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0041] Oxalic acid, CAS No. 144-62-7, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0042] Citric acid, CAS No. 77-92-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0043] Nickel sulfate, CAS No. 7786-81-4, was purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0044] Cobalt sulfate, CAS No. 10124-43-3, was purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0045] Manganese sulfate, CAS No. 7785-87-7, was purchased from Shanghai MacLean Biochemical Co., Ltd.;

[0046] Urea, CAS No. 57-13-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0047] Tetrahydrofuran, CAS No. 109-99-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0048] Tetrabutylammonium chloride, CAS No. 1112-67-0, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0049] Example 1

[0050] This embodiment provides a method for recycling waste ternary lithium batteries, comprising the following steps:

[0051] Step S1: discharging and disassembling the waste ternary lithium battery to obtain the positive electrode active material of the ternary lithium battery; placing 20 parts of the positive electrode active material in 220 parts of a mixed solvent (200 parts of N,N-dimethylacetamide and 20 parts of triethylamine) by weight for ultrasonic treatment (temperature of 70°C, power of 220W, time of 1h), then drying and ball milling to obtain the pretreated ternary lithium battery positive electrode material powder, while retaining the mixed solvent subjected to ultrasonic treatment;

[0052] Step S2: In parts by weight, 14 parts of 1,6-hexanediamine are added to 40 parts of chloroform, stirred for 20 minutes, and then 18 parts of glycidol are added dropwise, reacted at 70° C. for 4 hours, and the solvent is evaporated at room temperature using a rotary evaporator to obtain a first intermediate; 50 parts of the first intermediate are added to 220 parts of the ultrasonically treated mixed solvent in step S1, stirred for 20 minutes, and then 20 parts of hexafluoropropylene oxide trimer are added to react for 8 hours, extracted and washed with hydrochloric acid having a molar concentration of 0.1 mol / L, the lower layer is removed, and then washed with deionized water for 3 times to obtain a second intermediate; 9 parts of the second intermediate and 4 parts of potassium carbonate are added to 20 parts of anhydrous ethanol, stirred for 20 minutes, and then 4 parts of iodomethane are added, reacted at room temperature for 8 hours, filtered, and rotary evaporated to obtain a modified quaternary ammonium salt;

[0053] Step S3: by weight, 25 parts of the modified quaternary ammonium salt described in step S2 are added to 100 parts of propylene glycol, stirred at 300 r / min for 2 hours, and then 30 parts of oxalic acid are added, and reacted at 60° C. for 30 minutes to obtain a low eutectic solvent;

[0054] Step S4: adding 12 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 220 parts of the low eutectic solvent in step S3, and then stirring the mixture for reaction (stirring speed of 1200 r / min, reaction temperature of 90° C., reaction time of 1 h), filtering the mixture after the reaction is completed to obtain a metal ion leachate;

[0055] Preparation of fluorine-containing nickel-cobalt-manganese salt: In parts by weight, 2.5 parts of nickel sulfate, 0.4 parts of cobalt sulfate and 0.3 parts of manganese sulfate are added to 100 parts of deionized water, stirred for 20 minutes, and then 0.6 parts of urea and 0.8 parts of the modified quaternary ammonium salt described in step S2 are added, and stirred for 30 minutes; then 12 parts of tetrahydrofuran are added for hydrothermal reaction (reaction temperature is 120°C, reaction time is 10 hours), and after the hydrothermal reaction is completed, centrifugation is performed, the lower solid phase is removed, washed with deionized water, and vacuum dried to obtain fluorine-containing nickel-cobalt-manganese salt.

[0056] Step S5: In parts by weight, 15 parts of fluorine-containing nickel cobalt manganese salt are added to 220 parts of the metal ion leaching solution in step S4, and stirred for 30 minutes to obtain a precursor solution. The precursor solution is heated to react (the reaction temperature is 125°C and the reaction time is 20 hours). After the reaction is completed, it is filtered, washed and dried in sequence to obtain a positive electrode recycled material recovered from a waste ternary lithium battery.

[0057] Example 2

[0058] This embodiment provides a method for recycling waste ternary lithium batteries, comprising the following steps:

[0059] Step S1: discharging and disassembling the waste ternary lithium battery to obtain the positive electrode active material of the ternary lithium battery; placing 10 parts of the positive electrode active material in 200 parts of a mixed solvent (180 parts of N,N-dimethylacetamide and 20 parts of triethylamine) by weight for ultrasonic treatment (temperature of 60°C, power of 200W, time of 2h), then drying and ball milling to obtain the pretreated ternary lithium battery positive electrode material powder, while retaining the mixed solvent subjected to ultrasonic treatment;

[0060] Step S2: In parts by weight, 12 parts of 1,6-hexanediamine are added to 30 parts of chloroform, stirred for 10 minutes, and then 16 parts of glycidol are added dropwise, reacted at 60° C. for 4 hours, and the solvent is evaporated at room temperature using a rotary evaporator to obtain a first intermediate; 40 parts of the first intermediate are added to 200 parts of the ultrasonically treated mixed solvent in step S1, stirred for 10 minutes, and then 16 parts of hexafluoropropylene oxide trimer are added to react for 8 hours, extracted and washed with hydrochloric acid having a molar concentration of 0.1 mol / L, the lower layer is removed, and then washed with deionized water for 3 times to obtain a second intermediate; 7 parts of the second intermediate and 2 parts of potassium carbonate are added to 15 parts of anhydrous ethanol, stirred for 10 minutes, and then 2 parts of iodomethane are added, reacted at room temperature for 6 hours, filtered, and rotary evaporated to obtain a modified quaternary ammonium salt;

[0061] Step S3: by weight, 20 parts of the modified quaternary ammonium salt described in step S2 are added to 80 parts of propylene glycol, stirred at 200 r / min for 1 hour, and then 20 parts of citric acid are added, and reacted at 50° C. for 40 minutes to obtain a low eutectic solvent;

[0062] Step S4: adding 10 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 200 parts of the low eutectic solvent in step S3, and then stirring the mixture to react (stirring speed of 100 r / min, reaction temperature of 80° C., reaction time of 2 h), filtering the mixture after the reaction is completed to obtain a metal ion leachate;

[0063] Preparation of fluorine-containing nickel-cobalt-manganese salt: In parts by weight, 2.2 parts of nickel sulfate, 0.2 parts of cobalt sulfate and 0.1 parts of manganese sulfate are added to 80 parts of deionized water, stirred for 10 minutes, and then 0.4 parts of urea and 0.5 parts of the modified quaternary ammonium salt described in step S2 are added, and stirred for 20 minutes; then 10 parts of tetrahydrofuran are added for hydrothermal reaction (reaction temperature is 110°C, reaction time is 10 hours), and after the hydrothermal reaction is completed, centrifugation is performed, the lower solid phase is removed, washed with deionized water, and vacuum dried to obtain fluorine-containing nickel-cobalt-manganese salt.

[0064] Step S5: In parts by weight, 10 parts of fluorine-containing nickel, cobalt and manganese salt are added to 200 parts of the metal ion leaching solution of step S4, and stirred for 20 minutes to obtain a precursor solution. The precursor solution is heated to react (the reaction temperature is 120°C and the reaction time is 18 hours). After the reaction is completed, it is filtered, washed and dried in sequence to obtain a positive electrode recycled material recovered from a waste ternary lithium battery.

[0065] Example 3

[0066] This embodiment provides a method for recycling waste ternary lithium batteries, comprising the following steps:

[0067] Step S1: discharging and disassembling the waste ternary lithium battery to obtain the positive electrode active material of the ternary lithium battery; placing 15 parts of the positive electrode active material in 210 parts of a mixed solvent (190 parts of N,N-dimethylacetamide and 20 parts of triethylamine) by weight for ultrasonic treatment (temperature of 65°C, power of 208W, time of 2h), then drying and ball milling to obtain the pretreated ternary lithium battery positive electrode material powder, while retaining the mixed solvent subjected to ultrasonic treatment;

[0068] Step S2: In parts by weight, 13 parts of 1,6-hexanediamine are added to 38 parts of chloroform, stirred for 15 minutes, and then 17 parts of glycidol are added dropwise, reacted at 68° C. for 5 hours, and the solvent is evaporated at room temperature using a rotary evaporator to obtain a first intermediate; 46 parts of the first intermediate are added to 210 parts of the ultrasonically treated mixed solvent in step S1, stirred for 17 minutes, and then 18 parts of hexafluoropropylene oxide trimer are added to react for 9 hours, extracted and washed with hydrochloric acid having a molar concentration of 0.1 mol / L, the lower layer is removed, and then washed with deionized water for 3 times to obtain a second intermediate; 8 parts of the second intermediate and 3 parts of potassium carbonate are added to 16 parts of anhydrous ethanol, stirred for 15 minutes, and then 3 parts of iodomethane are added, reacted at room temperature for 7 hours, filtered, and rotary evaporated to obtain a modified quaternary ammonium salt;

[0069] Step S3: by weight, 22 parts of the modified quaternary ammonium salt described in step S2 are added to 90 parts of propylene glycol, stirred at 260 r / min for 2 hours, and then 25 parts of oxalic acid are added, and reacted at 58° C. for 32 minutes to obtain a low eutectic solvent;

[0070] Step S4: adding 11 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 210 parts of the low eutectic solvent in step S3, and then stirring to react (stirring speed of 160 r / min, reaction temperature of 85° C., reaction time of 2 h), filtering after the reaction is completed to obtain a metal ion leachate;

[0071] Preparation of fluorine-containing nickel-cobalt-manganese salt: In parts by weight, 2.4 parts of nickel sulfate, 0.3 parts of cobalt sulfate and 0.2 parts of manganese sulfate are added to 90 parts of deionized water, stirred for 16 minutes, and then 0.5 parts of urea and 0.6 parts of the modified quaternary ammonium salt described in step S2 are added, and stirred for 25 minutes; then 11 parts of tetrahydrofuran are added for hydrothermal reaction (reaction temperature is 115°C, reaction time is 11 hours), and after the hydrothermal reaction is completed, centrifugation is performed, the lower solid phase is removed, washed with deionized water, and vacuum dried to obtain fluorine-containing nickel-cobalt-manganese salt.

[0072] Step S5: In parts by weight, 12 parts of fluorine-containing nickel, cobalt and manganese salt are added to 210 parts of the metal ion leaching solution in step S4, and stirred for 26 minutes to obtain a precursor solution. The precursor solution is heated to react (the reaction temperature is 122°C and the reaction time is 19 hours). After the reaction is completed, it is filtered, washed and dried in sequence to obtain a positive electrode recycled material recovered from a waste ternary lithium battery.

[0073] Comparative Example 1

[0074] This comparative example provides a method for recycling waste ternary lithium batteries, comprising the following steps:

[0075] Step S1: discharging and disassembling the waste ternary lithium battery to obtain the positive electrode active material of the ternary lithium battery; by weight, 20 parts of the positive electrode active material are placed in 220 parts of N,N-dimethylacetamide for ultrasonic treatment (temperature of 70°C, power of 220W, time of 1h), and then dried and ball-milled to obtain the pre-treated ternary lithium battery positive electrode material powder;

[0076] Step S2: by weight, add 25 parts of tetrabutylammonium chloride from the step to 100 parts of propylene glycol, stir at 300 r / min for 2 hours, then add 30 parts of oxalic acid, react at 60° C. for 30 minutes to obtain a low eutectic solvent;

[0077] Step S3: adding 12 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 220 parts of the low eutectic solvent in step S2, and then stirring the mixture for reaction (stirring speed of 1200 r / min, reaction temperature of 90° C., reaction time of 1 h), filtering the mixture after the reaction is completed to obtain a metal ion leachate;

[0078] Step S4: In parts by weight, 15 parts of nickel sulfate are added to 220 parts of the metal ion leaching solution in step S3, and stirred for 30 minutes to obtain a precursor solution. The precursor solution is heated to react (the reaction temperature is 125°C and the reaction time is 20 hours). After the reaction is completed, it is filtered, washed and dried in sequence to obtain a positive electrode recycled material recovered from a waste ternary lithium battery.

[0079] Comparative Example 2

[0080] This comparative example provides a method for recycling waste ternary lithium batteries. The difference between this comparative example and Example 1 is that tetrabutylammonium chloride is used to replace the modified quaternary ammonium salt, and nickel sulfate is used to replace the fluorine-containing nickel cobalt manganese salt. The rest is the same as Example 1.

[0081] Comparative Example 3

[0082] This comparative example provides a method for recycling waste ternary lithium batteries. The difference between this comparative example and Example 1 is that N,N-dimethylacetamide is used to replace the blending solvent, and tetrabutylammonium chloride is used to replace the modified quaternary ammonium salt. The rest is the same as Example 1.

[0083] Comparative Example 4

[0084] This comparative example provides a method for recycling waste ternary lithium batteries. The difference between this comparative example and Example 1 is that nickel sulfate is used to replace the fluorine-containing nickel cobalt manganese salt, and the rest is the same as Example 1.

[0085] Performance Testing

[0086] The positive electrode regeneration materials obtained by the above-mentioned embodiment and comparative recovery method were subjected to performance tests, and the sources of some components used in the tests are as follows:

[0087] Polyvinylidene fluoride, product number P302014, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0088] N-Methylpyrrolidone, CAS No. 872-50-4, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0089] Conductive carbon black, product number Super P, was purchased from Grafit Materials Co., Ltd.;

[0090] Aluminum foil, item number H18-1100, purchased from Shenzhen Honglei Metal Materials Co., Ltd.;

[0091] Electrode shell, CR2025 type, purchased from Shanxi Lizhiyuan Battery Materials Co., Ltd.;

[0092] Electrolyte, product number TC-E201, purchased from Guangzhou Tianci High-tech Materials Co., Ltd.;

[0093] Diaphragm, polypropylene PP, Celgard 2400 type, purchased from Suzhou Shengernuo Technology Co., Ltd.;

[0094] Metal lithium negative electrode sheet, item number xk-li28, was purchased from Changsha Xinkang New Materials Co., Ltd.

[0095] 1. Battery Assembly

[0096] (1) Slurry preparation: In parts by weight, 4 parts of polyvinylidene fluoride are added to 100 parts of N-methylpyrrolidone, and the mixture is stirred evenly to obtain a binder; 8 parts of the positive electrode regeneration materials of the embodiment and the comparative example, 1 part of conductive carbon black and 1 part of the binder are stirred evenly, and then 10 parts of N-methylpyrrolidone are added and stirred for 1 hour to completely mix the components to obtain a positive electrode slurry.

[0097] (2) Preparation of electrode sheets: The positive electrode slurry is evenly coated on the aluminum foil with a coating thickness of 100 μm, and then placed in a forced air drying oven for drying at 80°C for 3 h. After drying, a manual cutter is used to cut out positive electrode discs with a diameter of 14 mm, and then placed in a vacuum drying oven for drying at 120°C for 12 h to obtain positive electrode sheets.

[0098] (3) Assembling the battery: In an argon-filled glove box, first place the prepared positive electrode in the middle of the electrode shell and drip electrolyte to moisten the electrode. Then place it in the diaphragm and drip electrolyte until the diaphragm is moistened. Finally, add the metal lithium negative electrode and other accessories, and seal it with a button battery sealing machine to form a button battery.

[0099] 2. First charge and discharge specific capacity test

[0100] Use a current density of 0.1C for the first charge and discharge capacity test, define 1C as 140mA / g, charge at constant current to 4.95V, discharge at constant current to 3.0V, and record the test data.

[0101] Table 1 Performance test results

[0102]

[0103] It can be seen from the above performance test results that Examples 1-3 have good effects, and the battery prepared from the positive electrode regeneration material has a first charge specific capacity of 229.14~235.55mAh / g, a first discharge specific capacity of 181.06~183.12mAh / g, and a coulombic efficiency of 77.74~79.02%; this is because the PVDF binder is dissolved in a mixed solvent composed of N,N-dimethylacetamide and triethylamine, and then a modified quaternary ammonium salt is prepared based on the mixed solvent, and the modified quaternary ammonium salt is applied to a low eutectic solvent, and the quaternary ammonium salt is used to obtain a fluorine-containing nickel cobalt manganese salt, so that the positive electrode regeneration material recovered from waste ternary lithium batteries exhibits excellent electrochemical properties.

[0104] However, since the comparative example did not adopt the necessary technical scheme, it was significantly worse than the embodiment in the corresponding performance test. Compared with Example 1, Comparative Example 1 used N, N-dimethylacetamide to replace the blended solvent, tetrabutylammonium chloride to replace the modified quaternary ammonium salt, and nickel sulfate to replace the fluorine-containing nickel cobalt manganese salt, and the first charge specific capacity, first discharge specific capacity and coulombic efficiency decreased; compared with Example 1, Comparative Example 2 used tetrabutylammonium chloride to replace the modified quaternary ammonium salt, and nickel sulfate to replace the fluorine-containing nickel cobalt manganese salt, and the first charge specific capacity, first discharge specific capacity and coulombic efficiency decreased; compared with Example 1, Comparative Example 3 used N, N-dimethylacetamide to replace the blended solvent, and tetrabutylammonium chloride to replace the modified quaternary ammonium salt, and the first charge specific capacity, first discharge specific capacity and coulombic efficiency decreased; compared with Example 1, Comparative Example 4 used nickel sulfate to replace the fluorine-containing nickel cobalt manganese salt, and the first charge specific capacity, first discharge specific capacity and coulombic efficiency decreased.

[0105] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recycling waste ternary lithium batteries, characterized in that: The following steps are involved: Step S1: pre-treating the waste ternary lithium battery to obtain the ternary lithium battery positive electrode active material; In parts by weight, 10 to 20 parts of the positive electrode active material are placed in 200 to 220 parts of a mixed solvent for ultrasonic treatment, and then dried and ball-milled to obtain a pretreated ternary lithium battery positive electrode material powder, while retaining the mixed solvent that has been ultrasonically treated; The mixed solvent is N,N-dimethylacetamide and triethylamine; wherein the mass ratio of N,N-dimethylacetamide to triethylamine is (9-10):1; Step S2: by weight, 12 to 14 parts of 1,6-hexanediamine are added to 30 to 40 parts of chloroform, stirred for 10 to 20 minutes, and then 16 to 18 parts of glycidol are added dropwise, reacted at 60 to 70° C. for 4 to 6 hours, and the solvent is evaporated at room temperature using a rotary evaporator to obtain a first intermediate; 40 to 50 parts of the first intermediate are added to 200 to 220 parts of the mixed solvent treated with ultrasound in step S1, stirred for 10 to 20 minutes, and then stirred for 10 to 20 minutes. min, then add 16 to 20 parts of hexafluoropropylene oxide trimer to react for 8 to 10 hours, extract and wash with hydrochloric acid with a molar concentration of 0.1 mol / L, take the lower layer, and then wash it with deionized water for 3 times to obtain a second intermediate; add 7 to 9 parts of the second intermediate and 2 to 4 parts of potassium carbonate to 15 to 20 parts of anhydrous ethanol, stir for 10 to 20 minutes, then add 2 to 4 parts of iodomethane, react at room temperature for 6 to 8 hours, filter, and rotary evaporate to obtain a modified quaternary ammonium salt; Step S3: adding 20 to 25 parts of the modified quaternary ammonium salt described in step S2 to 80 to 100 parts of propylene glycol by weight, stirring at 200 to 300 r / min for 1 to 2 hours, then adding 20 to 30 parts of an acid compound, reacting at 50 to 60° C. for 30 to 40 minutes to obtain a low eutectic solvent; Step S4: adding 10 to 12 parts by weight of the ternary lithium battery positive electrode material powder pretreated in step S1 to 200 to 220 parts of the low eutectic solvent in step S3, and then stirring to react, and filtering after the reaction is completed to obtain a metal ion leachate; Step S5: adding 10 to 15 parts by weight of fluorine-containing nickel-cobalt-manganese salt to 200 to 220 parts of the metal ion leaching solution of step S4, stirring for 20 to 30 minutes to obtain a precursor solution, heating the precursor solution for reaction, and filtering, washing and drying the precursor solution in sequence after the reaction is completed to obtain a positive electrode recycled material recovered from a waste ternary lithium battery; The reaction temperature of the heating reaction is 120-125°C, and the reaction time is 18-20 hours. The preparation method of the fluorine-containing nickel-cobalt-manganese salt comprises: adding 2.2-2.5 parts of nickel sulfate, 0.2-0.4 parts of cobalt sulfate and 0.1-0.3 parts of manganese sulfate to 80-100 parts of deionized water by weight, stirring for 10-20 minutes, then adding 0.4-0.6 parts of urea and 0.5-0.8 parts of the modified quaternary ammonium salt described in step S2, and stirring for 20-30 minutes; then adding 10-12 parts of tetrahydrofuran for hydrothermal reaction, centrifuging after the hydrothermal reaction is completed, taking the solid phase, washing with deionized water, and vacuum drying to obtain the fluorine-containing nickel-cobalt-manganese salt; the reaction temperature of the hydrothermal reaction is 110-120°C, and the reaction time is 10-12 hours.

2. The method for recycling waste ternary lithium batteries according to claim 1, characterized in that: The pre-treatment in step S1 includes a discharge treatment and a disassembly treatment.

3. The method for recycling waste ternary lithium batteries according to claim 1, characterized in that: The ultrasonic temperature of the ultrasonic treatment in step S1 is 60-70° C., the ultrasonic power is 200-220 W, and the ultrasonic time is 1-2 h.

4. The method for recycling waste ternary lithium batteries according to claim 1, characterized in that: The acid compound in step S3 is selected from any one of oxalic acid, citric acid and malic acid, or a combination of at least two thereof.

5. The method for recycling waste ternary lithium batteries according to claim 1, characterized in that: The stirring speed of the stirring reaction in step S4 is 100-200 r / min, the reaction temperature is 80-90° C., and the reaction time is 1-2 h.

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