A regenerated ternary material and its preparation method

Abstract

The present disclosure provides a regenerated ternary material and a preparation method thereof, relating to the technical field of lithium batteries. The preparation method includes: S1, performing a separation operation on the positive electrode sheet of a waste lithium battery to obtain a recycled ternary material; S2, preparing a corresponding lithium source solution according to the recycled ternary material; S3, mixing the lithium source solution with a promoter to obtain a mixed solution; S4, adding the recycled ternary material to the mixed solution and performing a mixing treatment to obtain a suspension; subjecting the suspension to microwave hydrothermal treatment to obtain a hydrothermal product; S5, performing a sintering treatment on the hydrothermal product to obtain a regenerated ternary material. By recycling the ternary material, adding a promoter and supplementing the lithium source for sintering, multiple repairs of the structure and performance of the ternary positive electrode material are achieved. And by means of microwave hydrothermal treatment, the infiltration degree of the promoter in the recycled material is increased, promoting the crystal phase transformation of the material, and the obtained regenerated ternary material has good chemical stability.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lithium batteries, and in particular to a recycled ternary material and a preparation method thereof. Background Art

[0002] As energy and environmental issues become increasingly prominent, lithium-ion batteries are widely used in portable electronic products, electric vehicles, energy storage and other fields due to their excellent performance and environmentally friendly characteristics such as high voltage, high power density and long life. Generally, lithium-ion batteries will inevitably experience capacity decay and voltage decay after 5 to 10 years of use, resulting in a large number of waste lithium-ion batteries. It is estimated that by 2030, more than 11 million tons of waste lithium-ion batteries will be disposed of. On the one hand, the large-scale disposal of lithium-ion batteries will lead to resource shortages and continued price increases of precious metals (such as Li, Ni, Co, Mn, etc.). On the other hand, flammable and toxic wastes from lithium-ion batteries, such as organic solvents, electrolytes and heavy metals, will also cause serious environmental problems. The recycling of waste lithium-ion batteries is of great significance for economic value and environmental protection.

[0003] To recycle waste lithium-ion batteries, it is necessary to first disassemble the batteries to obtain waste positive electrode materials, and then repair and regenerate the waste positive electrode materials. At present, there are two methods for single crystal repair and regeneration of waste positive electrode materials. One is to add heterogeneous seed crystals (such as lithium manganese oxide with a spinel structure) to the waste positive electrode materials and calcine them at high temperature to achieve the morphological transformation and regeneration of waste polycrystalline materials into single crystal materials. Another method is to crush the waste positive electrode materials and then calcine them in molten salt to obtain regenerated flaky single crystal materials. However, the former method requires additional addition of seed crystal materials, and the performance of the regenerated materials obtained is poor. The latter method will cause secondary attenuation of the performance of the positive electrode material during the crushing process, making the repair more difficult, and usually requires acid or alkali treatment, which causes great environmental pollution and complicated procedures.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In order to solve the above technical problems, the present disclosure provides a recycled ternary material and a preparation method thereof.

[0006] The first aspect of the present disclosure provides a method for preparing a recycled ternary material, comprising:

[0007] S1, separating the positive electrode sheets of waste lithium batteries to obtain recycled ternary materials;

[0008] S2. Prepare a corresponding lithium source solution according to the recycled ternary material.

[0009] S3. Mix the lithium source solution with a promoter to obtain a mixed solution.

[0010] S4. Add the recycled ternary material to the mixed solution, and perform a mixing process to obtain a suspension; perform microwave hydrothermal treatment on the suspension to obtain a hydrothermal product.

[0011] S5. Perform a sintering process on the hydrothermal product to obtain the recycled ternary material.

[0012] In an exemplary embodiment of the present disclosure, in step S3, the promoter is selected from one or more of strontium oxide, strontium hydroxide, strontium nitrate, barium hydroxide, barium nitrate, and aluminum trifluoride.

[0013] In an exemplary embodiment of the present disclosure, in step S3, the dosage of the promoter is 0.05% - 1% of the dosage of the recycled ternary material.

[0014] In an exemplary embodiment of the present disclosure, in step S4, the parameters of the microwave hydrothermal treatment are: microwave power is 500 - 2000W, temperature is 40 - 100°C, and treatment time is 0.5 - 5h.

[0015] In an exemplary embodiment of the present disclosure, in step S5, before sintering, the hydrothermal product is first subjected to drying and sieving treatments. The drying temperature is 80 - 150°C, and the drying time is 6 - 24h; the sieve mesh for the sieving treatment is 40 - 200 meshes.

[0016] In an exemplary embodiment of the present disclosure, in step S5, the temperature of the sintering process is 800 - 1000°C, and the sintering time is 6 - 20h.

[0017] In an exemplary embodiment of the present disclosure, in step S5, during the sintering process, the heating rate is 3 - 8°C / min, and the sintering process is carried out in an oxygen atmosphere.

[0018] In an exemplary embodiment of the present disclosure, in step S2, the preparing a corresponding lithium source solution according to the recycled ternary material includes:

[0019] Perform elemental analysis on the recycled ternary material to obtain the contents of lithium element and the main element; wherein, the main element is nickel - cobalt - manganese element or nickel - cobalt - aluminum element.

[0020] According to the elemental analysis results, prepare a corresponding lithium source solution according to the molar ratio of lithium element to the main element being 1:1.02 - 1.10; the molar concentration of the lithium source solution is 1 - 8mol / L.

[0021] In an exemplary embodiment of the present disclosure, in step S3, the mixing step includes mechanical stirring and / or heat treatment.

[0022] In an exemplary embodiment of the present disclosure, in step S4, the mass concentration of the recycled ternary material in the suspension is 50 - 2000 g / L.

[0023] A second aspect of the present disclosure provides a recycled ternary material prepared by the preparation method described in any one of the above.

[0024] The beneficial effects of the recycled ternary material and its preparation method according to the embodiments of the present disclosure are as follows:

[0025] The preparation method of the recycled ternary material of the present disclosure configures a corresponding lithium source solution according to the metal content in the obtained recycled ternary material. After reacting the recycled ternary material, the lithium source solution and the promoter under microwave hydrothermal conditions, sintering treatment is carried out to obtain the recycled ternary material. By adding the promoter and performing microwave hydrothermal treatment, it helps the promoter to efficiently and uniformly infiltrate the waste materials, enabling the interface fusion of the primary particles of the waste polycrystalline materials at a lower temperature, and the internal microparticles of the waste polycrystalline materials are transformed into a reconstructed single crystal material with regular and periodic arrangement. In addition, when the promoter is sintered at high temperature, the atoms in the promoter can replace the transition metal atoms in the material, achieving multiple repairs of the structure and performance of the ternary cathode material, increasing the structural stability of the material, and providing favorable conditions for the deintercalation and intercalation of lithium ions. The recycled material obtained by this preparation method has higher electrochemical stability.

[0026] In addition, the preparation process of the above-mentioned recycled ternary material is simple, and various parameters are easy to control. There is no need to carry out acid leaching or alkali leaching steps, which saves energy, is environmentally friendly, and is easy to carry out large-scale production.

[0027] It should be understood that the above general description and subsequent detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a flowchart of the preparation method of the recycled ternary material according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not indicated with the manufacturer are all conventional products that can be obtained through commercial purchase.

[0031] The following specifically describes the recycled ternary material and its preparation method according to the embodiments of the present disclosure.

[0032] A preparation method of a recycled ternary material provided by an embodiment of the present disclosure includes:

[0033] Step S1: Perform a separation operation on the positive electrode sheet of a waste lithium battery to obtain a recycled ternary material;

[0034] Step S2: Prepare a corresponding lithium source solution according to the recycled ternary material;

[0035] Step S3: Mix the lithium source solution with a promoter to obtain a mixed solution;

[0036] Step S4: Add the recycled ternary material to the mixed solution, perform a mixing treatment to obtain a suspension; subject the suspension to microwave hydrothermal treatment to obtain a hydrothermal product;

[0037] Step S5: Perform a sintering treatment on the hydrothermal product to obtain the recycled ternary material.

[0038] Implementing the preparation method of the present disclosure, after reacting the recycled ternary material, the lithium source solution, and the promoter under microwave hydrothermal conditions, and then performing a sintering treatment, a recycled ternary material is obtained. There is no need for a crushing treatment, avoiding the adverse effects of the mechanical crushing process on the material properties. A promoter is added during the preparation process and microwave hydrothermal treatment is performed, which helps the promoter to efficiently and uniformly infiltrate the waste materials, facilitating the fusion of the primary particle interfaces of the waste polycrystalline materials in the subsequent sintering stage, and the internal microparticles of the waste polycrystalline materials are transformed into a reconstructed single crystal material with regular and periodic arrangements. In addition, when the added promoter is sintered at a high temperature, the atoms in the promoter can replace the transition metal atoms in the material, achieving multiple repairs of the structure and performance of the ternary positive electrode material, increasing the structural stability of the material, and the obtained recycled material has higher electrochemical stability.

[0039] The following specifically describes each step of the preparation method in combination with embodiments.

[0040] In step S1, a separation operation is performed on the positive electrode sheet of the waste lithium battery to obtain the recycled ternary material, which specifically includes: scraping the positive electrode sheet to obtain a powder material, and then performing a sieving treatment on the powder material to remove foreign matters such as aluminum chips to obtain the recycled ternary material. Specifically, the powder material is sieved through a 300-500 mesh sieve to remove foreign matters.

[0041] It can be understood that the waste lithium battery can be various types of ternary lithium batteries, and its positive electrode material can be lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminate ternary positive electrode material. For example, in the lithium nickel cobalt manganese oxide positive electrode material, the ratio of nickel, cobalt, and manganese can be 424, 333, 525, etc.

[0042] In step S2, a corresponding lithium source solution is prepared according to the recycled ternary material, which specifically includes:

[0043] Step S21, perform an elemental analysis on the recycled ternary material to obtain the contents of lithium element and the main elements. Among them, the main elements are nickel cobalt manganese elements or nickel cobalt aluminum elements. Specifically, in this step, for example, ICP-MS (Inductively coupled plasma mass spectrometry) can be used to determine the contents of various metal elements in the recycled ternary material.

[0044] It should be noted that in step S21, when the recycled ternary material is lithium nickel cobalt manganese oxide, the main elements are nickel element, cobalt element, and manganese element; when the recycled ternary material is lithium nickel cobalt aluminate, the main elements are nickel element, cobalt element, and aluminum element.

[0045] Step S22, according to the elemental analysis results, prepare a corresponding lithium source solution according to the molar ratio of lithium element to the main elements of 1:1.02-1.10. That is, when the recycled ternary material is lithium nickel cobalt manganese oxide, the molar ratio of the total amount of lithium element in the lithium source solution and the recycled ternary material to the total amount of nickel cobalt manganese elements is 1:1.02-1.10. According to this ratio, after deducting the content of lithium element in the recycled ternary material, the content of lithium element required for the lithium source solution is obtained.

[0046] Furthermore, the lithium source solution is selected from one or more of lithium carbonate solution, lithium hydroxide solution, lithium chloride solution, lithium nitrate solution, and lithium acetate solution.

[0047] Furthermore, the molar concentration of the lithium source solution is 1-8 mol / L. More preferably, the molar concentration of the lithium source solution is 4-8 mol / L, and at this molar concentration, the subsequent lithium supplementation efficiency is higher.

[0048] In step S3, the lithium source solution is mixed with a promoter to obtain a mixed solution.

[0049] In one embodiment of the present disclosure, in step S3, the promoter is selected from one or more of strontium oxide, strontium hydroxide, strontium nitrate, barium hydroxide, barium nitrate, and aluminum trifluoride. The above-mentioned promoters all have good water solubility, can effectively promote the efficient and uniform infiltration of the recycled ternary material, so as to realize the transformation of the internal waste polycrystalline material into a regularly and periodically arranged reconstructed single crystal material during the sintering process. In addition, the above-mentioned promoter can improve the performance of the ternary material, and there is no need for secondary sintering of molten salt separation, reducing energy consumption.

[0050] In one embodiment of the present disclosure, in step S3, the dosage of the promoter is 0.05-1% of the dosage of the recycled ternary material. That is, the weight of the promoter is 0.05-1% of the weight of the recycled ternary material. Further preferably, the dosage of the promoter is 0.1-0.8% of the dosage of the recycled ternary material. Under this condition, a good repair effect can be obtained.

[0051] In one embodiment of the present disclosure, in step S3, the mixing step includes mechanical stirring and / or heat treatment. Through mechanical stirring or heat treatment, the sufficient mixing of the lithium source solution and the promoter is ensured, and the smooth progress of the subsequent reaction is guaranteed.

[0052] Specifically, the mechanical stirring treatment is carried out by stirring and mixing with a stirrer, preferably, the rotation speed of the mechanical stirring is 100-500 r / min.

[0053] Specifically, the heat treatment can be carried out by heating with a heating rod or by water bath heating, and the temperature of the heat treatment is 30-100 °C. For example, it can be 30 °C, 50 °C, 80 °C, 100 °C, etc.

[0054] In step S4, the recycled ternary material is added to the mixed solution, and after mixing treatment, a suspension is obtained; the suspension is subjected to microwave hydrothermal treatment to obtain a hydrothermal product.

[0055] In one embodiment of the present disclosure, in step S4, the mass concentration of the recycled ternary material in the suspension is 50-2000 g / L. Further preferably, the mass concentration of the recycled ternary material in the suspension is 500-1600 g / L.

[0056] In one embodiment of the present disclosure, in step S4, the parameters of the microwave hydrothermal treatment are: the microwave power is 500-2000 W, the temperature is 40-100 °C, and the treatment time is 0.5-5 h. Further preferably, the microwave power is 800-1000 W, the temperature is 80-100 °C, and the treatment time is 2-4 h.

[0057] Through hydrothermal treatment with microwave, it is ensured that the promoter is fully infiltrated with the recycled ternary material. In the subsequent sintering stage, the grain boundary fusion of the primary particles of the polycrystalline material is ensured, promoting the transformation process of the polycrystalline material into a single-crystalline material. There is no need to add foreign seeds, shortening the preparation process, reducing energy consumption, and saving costs.

[0058] In step S5, the hydrothermal product is sintered to obtain the recycled ternary material.

[0059] In one embodiment of the present disclosure, in step S5, before sintering, the hydrothermal product is first subjected to drying and sieving treatments. The drying temperature is 80 - 150 °C, and the drying time is 6 - 24 h; the sieve mesh for the sieving treatment is 40 - 200 meshes.

[0060] In one embodiment of the present disclosure, in step S5, the sintering temperature is 800 - 1000 °C, and the sintering time is 6 - 20 h. Further preferably, the sintering temperature is 900 - 950 °C, and the sintering time is 10 - 16 h.

[0061] In one embodiment of the present disclosure, in step S5, during the sintering process, the heating rate is 3 - 8 °C / min, and the sintering process is carried out in an oxygen atmosphere. Specifically, industrial oxygen is introduced for sintering.

[0062] During sintering, through the coupling effect of the promoter and the sintering process, multiple repairs of the structure and function of the ternary cathode material are achieved, and the obtained recycled ternary material has better electrochemical stability.

[0063] The embodiment of the present disclosure also provides a recycled ternary material prepared according to the above-mentioned preparation method. Under the voltage condition of 4.35 V, the discharge specific capacity at 0.33 C is higher than 178.7 mAh / g, and the capacity retention rate is higher than 88% after 100 cycles at 45 °C and a rate of 1 C.

[0064] The embodiment of the present disclosure also provides a lithium-ion battery, including a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode includes the recycled ternary material as described above.

[0065] Further, in one embodiment, the preparation method of the positive electrode includes: mixing the above-mentioned recycled ternary material, carbon black, and binder in a certain mass ratio, adding an appropriate amount of water for grinding to obtain an electrode material; then coating the electrode material on a copper foil by a doctor blade method, and then performing vacuum drying to obtain the positive electrode.

[0066] Further, the binder can be selected, for example, as polyvinylidene fluoride PVDF, polyacrylic acid PAA, etc. The mass ratio of the recycled ternary material, carbon black, and binder can be, for example, 8:1:1.

[0067] The features and performance of the present disclosure will be further described in detail below in conjunction with the embodiments.

[0068] Unless otherwise specified, various raw materials, reagents, instruments, and equipment in the following embodiments of the present disclosure can be obtained through commercial means or prepared by existing methods. Among them, the recycled ternary material is LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM523).

[0069] Example 1

[0070] A recycled ternary material provided in this example is prepared according to the following steps:

[0071] (1) Sieving the cathode material scraped from the cathode plate through 325 meshes to remove foreign matters such as aluminum chips, and obtaining the recycled ternary material.

[0072] (2) Conducting ICP-MS elemental analysis on the sieved recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0073] (3) Preparing a lithium salt solution. According to the main element content tested by ICP-MS in the waste cathode material, lithium hydroxide is selected as the lithium salt. Weigh the corresponding amount of lithium hydroxide according to the molar ratio of lithium to the total molar number of nickel, cobalt, and manganese being 1.06 as the target ratio, add the lithium hydroxide to deionized water, and use a mechanical stirrer to accelerate the dissolution of lithium hydroxide. The concentration of the prepared lithium salt solution is 4 mol / L.

[0074] (4) Preparing a mixed solution. Add strontium oxide to the lithium salt solution, and the dosage of strontium oxide is 0.4 wt% of the total amount of the recycled ternary material to be treated. Take the corresponding strontium oxide and add it to the lithium salt solution, and continue to stir with a mechanical stirrer to obtain a mixed solution of lithium salt and strontium oxide.

[0075] (5) Add the separated and sieved recycled ternary material to the prepared mixed solution, and make the material-liquid ratio between the waste cathode material and the solution be 1500 g / L. After fully stirring evenly, form a uniform suspension.

[0076] (6) Conduct microwave hydrothermal treatment on the suspension, with a microwave power of 800 W, a microwave hydrothermal temperature of 100 °C, and a microwave hydrothermal treatment time of 3 h.

[0077] (7) Constantly drying the cathode material after microwave hydrothermal treatment to a constant weight, with the oven temperature set at 100 °C and the drying time being 20 h.

[0078] (8) Screen the dried cathode material through a 40-mesh sieve, load it into a crucible and put it into the furnace for high-temperature sintering. The sintering temperature is 940 °C, the time is 12 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and screening, the regenerated ternary single-crystal material is obtained.

[0079] Example 2

[0080] A regenerated ternary material provided in this example is prepared according to the following steps:

[0081] (1) Screen the cathode material scraped from the cathode plate through a 400-mesh sieve to remove foreign matters such as aluminum chips, and obtain the recycled ternary material.

[0082] (2) Perform ICP-MS elemental analysis on the screened recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0083] (3) Prepare a lithium salt solution. According to the main element content tested by ICP-MS in the waste cathode material, select lithium nitrate as the lithium salt, weigh the corresponding amount of lithium nitrate according to the molar ratio of lithium to the total molar amount of nickel, cobalt, and manganese being 1.08 as the target ratio, add the lithium nitrate to deionized water, and use a mechanical stirrer to accelerate the dissolution of lithium nitrate. The concentration of the prepared lithium salt solution is 6 mol / L.

[0084] (4) Prepare a mixed solution. Add barium hydroxide to the lithium salt solution, and the amount of barium hydroxide used is 0.2 wt% of the total amount of the recycled ternary material to be treated. Take the corresponding barium hydroxide and add it to the lithium salt solution, and continue to stir with a mechanical stirrer to obtain a mixed solution of lithium salt and barium hydroxide.

[0085] (5) Add the separated and screened recycled ternary material to the prepared mixed solution, and make the material-liquid ratio between the waste cathode material and the solution be 600 g / L. After fully stirring evenly, form a uniform suspension.

[0086] (6) Perform microwave hydrothermal treatment on the suspension. The microwave power is 900 W, the microwave hydrothermal temperature is 80 °C, and the microwave hydrothermal treatment time is 2 h.

[0087] (7) Constantly dry the cathode material after microwave hydrothermal treatment to a constant weight. The oven temperature is set at 120 °C, and the drying time is 14 h.

[0088] (8) Screen the dried cathode material through a 60-mesh sieve, load it into a crucible and put it into the furnace for high-temperature sintering. The sintering temperature is 940 °C, the time is 16 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and screening, the regenerated ternary single-crystal material is obtained.

[0089] Example 3

[0090] A regenerated ternary material provided by this embodiment is prepared according to the following steps:

[0091] (1) Sieving the cathode material scraped from the cathode plate through 400 meshes to remove foreign matters such as aluminum chips, and obtaining the recycled ternary material.

[0092] (2) Conducting ICP-MS elemental analysis on the sieved recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0093] (3) Preparing a lithium salt solution. According to the main element content tested by ICP-MS in the waste cathode material, lithium chloride is selected as the lithium salt. Weigh the corresponding amount of lithium chloride according to the molar ratio of lithium to the total molar amount of nickel, cobalt, and manganese being 1.08 as the target ratio. Add the lithium chloride into deionized water and use a mechanical stirrer to accelerate the dissolution of lithium chloride. The concentration of the prepared lithium salt solution is 4 mol / L.

[0094] (4) Preparing a mixed solution. Add aluminum fluoride into the lithium salt solution, and the dosage of aluminum fluoride is 0.8 wt% of the total amount of the recycled ternary material to be treated. Take the corresponding aluminum fluoride and add it into the lithium salt solution, and continue to stir with a mechanical stirrer to obtain a mixed solution of lithium salt and aluminum fluoride.

[0095] (5) Add the separated and sieved recycled ternary material into the prepared mixed solution, and make the material-liquid ratio between the waste cathode material and the solution be 1200 g / L. After fully stirring evenly, form a uniform suspension.

[0096] (6) Conduct microwave hydrothermal treatment on the suspension, with a microwave power of 900 W, a microwave hydrothermal temperature of 100 °C, and a microwave hydrothermal treatment time of 4 h.

[0097] (7) Constantly drying the cathode material after microwave hydrothermal treatment to a constant weight. Set the oven temperature at 100 °C, and the drying time is 16 h.

[0098] (8) Sieving the dried cathode material through 100 meshes, loading it into a crucible and putting it into the furnace for high-temperature sintering. The sintering temperature is 920 °C, the time is 10 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and sieving, the regenerated ternary single crystal material is obtained.

[0099] Example 4

[0100] A regenerated ternary material provided by this embodiment is prepared according to the following steps:

[0101] (1) Sieving the cathode material scraped from the cathode plate through 500 meshes to remove foreign matters such as aluminum chips, and obtaining the recycled ternary material.

[0102] (2) Perform ICP-MS elemental analysis on the sieved recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0103] (3) Prepare a lithium salt solution. According to the main element contents tested by ICP-MS in the waste cathode material, lithium carbonate is selected as the lithium salt. Weigh the corresponding amount of lithium carbonate according to the molar ratio of lithium to the total molar amount of nickel, cobalt, and manganese being 1.10 as the target ratio, add the lithium carbonate to deionized water, and use a mechanical stirrer to accelerate the dissolution of lithium carbonate. The concentration of the prepared lithium salt solution is 8 mol / L.

[0104] (4) Prepare a mixed solution. Add strontium nitrate to the lithium salt solution, and the dosage of strontium nitrate is 0.1 wt% of the total amount of the recycled ternary material to be treated. Take the corresponding strontium nitrate and add it to the lithium salt solution, and continue to stir with a mechanical stirrer to obtain a mixed solution of lithium salt and strontium nitrate.

[0105] (5) Add the separated and sieved recycled ternary material to the prepared mixed solution, and make the material-liquid ratio between the waste cathode material and the solution be 500 g / L. After fully stirring evenly, form a uniform suspension.

[0106] (6) Perform microwave hydrothermal treatment on the suspension. The microwave power is 900 W, the microwave hydrothermal temperature is 80 °C, and the microwave hydrothermal treatment time is 3 h.

[0107] (7) Constantly dry the cathode material after microwave hydrothermal treatment until it reaches a constant weight. The oven temperature is set at 100 °C, and the drying time is 16 h.

[0108] (8) Sieve the dried cathode material through 100 meshes, put it into a crucible and put it into the furnace for high-temperature sintering. The sintering temperature is 950 °C, the time is 12 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and screening, the regenerated ternary single crystal material is obtained.

[0109] Comparative Example 1

[0110] This comparative example provides a regenerated ternary material, which is prepared according to the following steps:

[0111] (1) Sieve the cathode material scraped from the cathode plate through 325 meshes to remove foreign matters such as aluminum chips to obtain the recycled ternary material.

[0112] (2) Perform ICP-MS elemental analysis on the sieved recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0113] (3) Prepare a lithium salt solution. According to the main element content analyzed by ICP-MS in the waste cathode material, lithium hydroxide is selected as the lithium salt. Weigh the corresponding amount of lithium hydroxide according to the molar ratio of lithium to the total molar amount of nickel, cobalt, and manganese being 1.06 as the target ratio. Add the lithium hydroxide to deionized water and use a mechanical stirrer to accelerate the dissolution of lithium hydroxide. The concentration of the prepared lithium salt solution is 4 mol / L.

[0114] (4) Add the separated and sieved recycled ternary material to the prepared lithium salt solution, and make the material-liquid ratio between the waste cathode material and the solution 1500 g / L. After fully stirring evenly, form a homogeneous suspension.

[0115] (5) Conduct microwave hydrothermal treatment on the suspension. The microwave power is 800 W, the microwave hydrothermal temperature is 100 °C, and the microwave hydrothermal treatment time is 3 h.

[0116] (6) Constantly dry the cathode material after microwave hydrothermal treatment until it reaches a constant weight. The oven temperature is set at 100 °C, and the drying time is 20 h.

[0117] (8) Sieve the dried cathode material through a 40-mesh sieve, put it into a crucible, and put it into the furnace for high-temperature sintering. The sintering temperature is 940 °C, the time is 12 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and screening, the recycled ternary single crystal material is obtained.

[0118] Comparative Example 2

[0119] This comparative example provides a recycled ternary material, which is prepared according to the following steps:

[0120] (1) Sieve the cathode material scraped from the cathode plate through a 325-mesh sieve to remove foreign matters such as aluminum chips, and obtain the recycled ternary material.

[0121] (2) Conduct ICP-MS elemental analysis on the sieved recycled ternary material to test the contents of nickel, cobalt, manganese, and lithium elements in the recycled ternary material.

[0122] (3) Prepare a lithium salt solution. According to the main element content analyzed by ICP-MS in the waste cathode material, lithium hydroxide is selected as the lithium salt. Weigh the corresponding amount of lithium hydroxide according to the molar ratio of lithium to the total molar amount of nickel, cobalt, and manganese being 1.06 as the target ratio. Add the lithium hydroxide to deionized water and use a mechanical stirrer to accelerate the dissolution of lithium hydroxide. The concentration of the prepared lithium salt solution is 4 mol / L.

[0123] (4) Add the separated and sieved recycled ternary material to the prepared lithium salt solution, and make the material-liquid ratio between the waste cathode material and the solution 1500 g / L. After fully stirring evenly, form a homogeneous suspension.

[0124] (5) Stir the suspension, and the stirring time is 3 h.

[0125] (6) Keep the positive electrode material after stirring at a constant temperature and dry it to a constant weight. The oven temperature is set at 100 °C, and the drying time is 20 h.

[0126] (8) Screen the dried positive electrode material through a 40-mesh sieve, put it into a crucible and put it into the furnace for high-temperature sintering. The sintering temperature is 940 °C, the time is 12 h, and the heat treatment atmosphere is high-purity oxygen. Then, through cooling, crushing, and screening, the regenerated ternary single-crystal material is obtained.

[0127] Test example

[0128] Coat and roll the regenerated ternary materials obtained in Examples 1-4 and Comparative Examples 1-2, and then assemble the electrode sheets to obtain button cells. The button cells are tested for the discharge specific capacity under the conditions of a voltage of 4.35 V and a current rate of 0.33 C. The results are shown in Table 1. And the capacity retention rate is tested after 100 cycles under the conditions of a high temperature of 45 °C and a current rate of 1 C. The results are shown in Table 1.

[0129] Table 1

[0130] Item Discharge specific capacity, mAh / g Capacity retention rate after 100 cycles, % Example 1 178.7 89.1 Example 2 179.2 88.9 Example 3 178.4 89.8 Example 4 179.0 88.5 Comparative Example 1 169.3 79.9 Comparative Example 2 158.4 68.7

[0131] As can be seen from Table 1, the discharge specific capacities of the regenerated ternary materials obtained in Examples 1-4 are 178.7 mAh / g, 179.2 mAh / g, 178.4 mAh / g, and 179.0 mAh / g respectively under the conditions of a voltage of 4.35 V and a current rate of 0.33 C, and the capacity retention rates after 100 cycles under the conditions of a high temperature of 45 °C and a current rate of 1 C are 89.1%, 88.9%, 89.8%, and 88.5% respectively. It can be seen that the regenerated ternary materials of the present disclosure have excellent electrochemical performance and good capacity retention rate. For the regenerated ternary material obtained in Comparative Example 1, due to the absence of a promoter, the capacity retention rate is relatively low. For the regenerated ternary material obtained in Comparative Example 2, due to the absence of a promoter and the lack of microwave hydrothermal treatment of the suspension, it is difficult to promote material repair, and the obtained material has poor electrochemical performance.

[0132] The embodiments described above are some embodiments of the present disclosure, rather than all embodiments. The detailed description of the embodiments of the present disclosure is not intended to limit the scope of the present disclosure claimed, but merely represents selected embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

Claims

1. A preparation method of a regenerated ternary material, characterized in that Including: S1. Separating the positive electrode sheet of the waste lithium battery to obtain recycled ternary material; S2. Preparing a corresponding lithium source solution according to the recycled ternary material; S3. Mixing the lithium source solution with a promoter to obtain a mixed solution; S4. Adding the recycled ternary material to the mixed solution, performing mixing treatment to obtain a suspension; subjecting the suspension to microwave hydrothermal treatment to obtain a hydrothermal product; S5. Performing sintering treatment on the hydrothermal product to obtain the recycled ternary material; In step S3, the promoter is selected from one or more of strontium oxide, strontium hydroxide, strontium nitrate, barium hydroxide, barium nitrate and aluminum trifluoride; In step S2, the preparation of the corresponding lithium source solution according to the recycled ternary material includes: performing elemental analysis on the recycled ternary material to obtain the contents of lithium element and main element, wherein the main element is nickel cobalt manganese element or nickel cobalt aluminum element; According to the elemental analysis result, a corresponding lithium source solution is prepared according to the molar ratio of lithium element to main element being 1:1.02 - 1.10; the molar concentration of the lithium source solution is 1 - 8 mol / L.

2. The preparation method of the regenerated ternary material according to claim 1, wherein In step S3, the dosage of the promoter is 0.05% - 1% of the dosage of the recycled ternary material.

3. The preparation method of the regenerated ternary material according to claim 1, wherein In step S4, the parameters of the microwave hydrothermal treatment are: microwave power is 500 - 2000 W, temperature is 40 - 100 °C, and treatment time is 0.5 - 5 h.

4. The preparation method of the regenerated ternary material according to claim 1, wherein, In step S5, before sintering the hydrothermal product, drying and sieving treatments are first performed. The drying temperature is 80 - 150 °C, and the drying time is 6 - 24 h; the sieve for the sieving treatment is 40 - 200 mesh.

5. The preparation method of the regenerated ternary material according to claim 1, wherein, In step S5, the sintering treatment temperature is 800 - 1000 °C, and the sintering time is 6 - 20 h.

6. The preparation method of the recycled ternary material according to claim 5, wherein, In step S5, during the sintering treatment, the heating rate is 3 - 8 °C / min, and the sintering treatment is carried out in an oxygen atmosphere.

7. The preparation method of the regenerated ternary material according to claim 1, characterized in that, In step S3, the mixing step includes mechanical stirring and / or heat treatment.

8. The preparation method of the regenerated ternary material according to claim 1, wherein In step S4, the mass concentration of the recycled ternary material in the suspension is 50 - 2000 g / L.

9. A regenerated ternary material, characterized in that, Prepared by the preparation method according to any one of claims 1 - 8.

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