Preparation method of regenerated high-nickel ternary material

Abstract

The invention relates to the technical field of lithium batteries, in particular to a preparation method of a regenerated high-nickel ternary material, and the preparation method comprises the following steps: classifying, discharging, disassembling and sorting a waste ternary lithium battery to obtain a ternary waste material; the ternary waste is subjected to pyrolysis treatment, ultrasonic treatment, sieving, smashing and sieving, and ternary waste fine powder is obtained; performing element determination on the ternary waste fine powder, then adding a nickel source, a cobalt source, a manganese source and a lithium source, adjusting the molar ratio of metal elements, and fully stirring and mixing to obtain a mixture; and sintering the mixture twice, crushing, screening and demagnetizing to obtain the regenerated high-nickel ternary material. The preparation method is simple to operate, acid-base leaching and extraction recovery are not involved in the whole process, harmful substances are not generated, and secondary pollution to the environment is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to a method for preparing a recycled high-nickel ternary material. Background Art

[0002] At present, the power batteries used in my country's new energy vehicles are mainly divided into two categories: ternary material lithium-ion batteries and lithium iron phosphate batteries. Among them, ternary materials have the advantages of high capacity and high energy density. They are considered to be the most promising lithium-ion battery positive electrode materials and have occupied the mainstream of the market.

[0003] The service life of ternary material lithium batteries is limited, so a large number of ternary material lithium batteries are scrapped every year. Waste ternary material lithium-ion batteries contain a large amount of rare and precious metals, such as Li, Ni, Co, Mn, Cu, Al and other valuable metals. If they are directly scrapped, the heavy metals and electrolytes in them will not only cause great damage to the natural environment, but also cause great waste of resources. Therefore, the recycling and regeneration of ternary materials has high economic and environmental value.

[0004] The current mainstream ternary material recycling method mainly adopts wet recycling, which involves acid, alkali dissolution, chemical precipitation and other steps; the alkali used mainly includes sodium hydroxide and potassium hydroxide, and the acid is divided into inorganic acid and organic acid, such as common inorganic acids include hydrochloric acid, sulfuric acid, nitric acid and even phosphoric acid, and organic acids include citric acid, malic acid, etc. Patent CN109750163A discloses a comprehensive recycling treatment method for ternary positive electrode materials and iron-lithium positive electrode materials, which recovers metals such as nickel, cobalt, manganese, and lithium through slurry adjustment, reduction, leaching and other steps; although the recovery rate of this method is high and the product purity is high, the recycling process involves the use of a large amount of acid, alkali and other solvents, which puts great pressure on environmental protection and operators, and easily causes secondary pollution, which restricts the recycling of waste lithium batteries.

[0005] Therefore, there is an urgent need for a method for recycling the ternary positive electrode material of waste batteries. Summary of the invention

[0006] The purpose of this application is to overcome the defect that the recycling of waste battery ternary positive electrode materials involves the use of a large amount of acid, alkali and other solvents, which easily causes secondary pollution. This application provides a preparation method for regenerated high-nickel ternary materials that does not involve acid, alkali and other solvents and is environmentally friendly.

[0007] In the first aspect, the present application provides a method for preparing a regenerated high-nickel ternary material using the following technical solution: A method for preparing a regenerated high-nickel ternary material comprises the following steps: S1. Classifying, discharging, disassembling and sorting the waste ternary lithium batteries to obtain ternary waste, pyrolyzing the ternary waste in an air atmosphere, ultrasonically treating the ternary waste after the pyrolysis treatment, and sieving to obtain coarse particles of the ternary waste; S2. crushing and sieving the coarse particles of the ternary waste in step S1 to obtain fine powder of the ternary waste; S3. Performing element determination on the ternary waste fine powder in step S2 to obtain the actual content ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder, and then adding a nickel source, a cobalt source, a manganese source and a lithium source to the ternary waste fine powder, adjusting the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder to 8:1:1:0.95-1.15, and fully stirring and mixing for 3-5 hours to obtain a mixture; S4. The mixed material in step 3 is sintered twice, the temperature of the first sintering is 450-550°C, and the holding time is 4-6 hours; after the first sintering, the temperature is then raised to 750-900°C for the second sintering, and the holding time is 10-15 hours to obtain a sintered material; S5. Crush, screen and demagnetize the sintered material in step S4 to obtain a regenerated high-nickel ternary material.

[0008] By adopting the above technical scheme, the ternary waste can be further crushed and separated by ultrasonic treatment after pyrolysis treatment, thereby improving the purity of the material. Adding nickel source, cobalt source, manganese source and lithium source to the ternary waste is to supplement the metal elements lost in the ternary waste, and to adjust the ratio of nickel, cobalt, manganese and lithium in the ternary waste to make a ternary material with a high nickel content; compared with the low-nickel ternary material, the high-nickel ternary material has a higher monomer energy density, which can improve the battery capacity and the first efficiency of the battery. Through secondary sintering, the particle structure of the ternary material can be made more stable, the shedding and damage of the particles can be reduced, the cycle life of the battery can be extended, the pores and defects generated during the primary sintering process can be eliminated, the internal resistance of the ternary material can be reduced, and the charge and discharge efficiency of the battery can be improved. The present invention can regenerate and repair the defects of waste ternary materials, and obtain high-performance regenerated high-nickel ternary materials, thereby reducing the cost of ternary lithium batteries and being conducive to the sustainable development of lithium-ion batteries; on the other hand, the preparation method is simple to operate, does not involve acid and alkali leaching and extraction recovery throughout the process, does not produce harmful substances, and avoids secondary pollution to the environment.

[0009] Optionally, in step S1, the temperature of the pyrolysis treatment is 400-600° C., and the insulation time is 3-6 hours.

[0010] By adopting the above technical scheme, pyrolysis treatment can decompose the organic binder in the waste ternary lithium battery, separate the metal part inside the battery from other components, and decompose or convert harmful substances in the battery into relatively safe products, thereby reducing harm to the environment and human body. The present invention achieves the separation and conversion of internal battery materials and avoids oxidation or burning of metal elements by strictly controlling the parameters of pyrolysis treatment.

[0011] Optionally, in step S1, a sieve with a mesh size of 150 to 400 is used for screening.

[0012] By adopting the above technical solution, a sieve with a mesh size of 150 to 400 is used to conduct a preliminary screening of waste ternary lithium batteries, separate ternary waste, and control the particle size of coarse particles of ternary waste, which is more conducive to subsequent crushing and screening.

[0013] Optionally, the nickel source is selected from one of nickel acetate, nickel carbonate and nickel hydroxide; And / or, the cobalt source is selected from one of cobalt acetate, cobalt carbonate and cobalt hydroxide; And / or, the manganese source is selected from one of manganese carbonate and manganese acetate; And / or, the lithium source is selected from one of lithium carbonate, lithium hydroxide, lithium oxalate and lithium acetate.

[0014] By adopting the above technical solution and selecting appropriate nickel source, cobalt source, manganese source and lithium source, it is more conducive to adjusting the proportion of metal element content in the ternary waste without introducing impurities.

[0015] Optionally, in step S4, sintering is performed in an oxygen-rich atmosphere.

[0016] By adopting the above-mentioned technical scheme, since some impurities may still remain in the lithium nickel cobalt manganese oxide waste after heat treatment, the present application adopts calcination in an oxygen atmosphere, which can remove some impurities remaining in the ternary waste through redox reaction; secondly, the oxygen-rich atmosphere can promote chemical reactions between ternary waste substances, such as solid-phase reactions, liquid-phase reactions, etc., so that the elements in the ternary waste can be better combined, thereby improving the purity and performance of the recycled high-nickel ternary material.

[0017] Optionally, in step S3, ICP detection is used to perform element determination on the ternary waste fine powder.

[0018] By adopting the above technical solution, ICP detection can realize the simultaneous determination of multiple elements with high measurement accuracy and low detection limit, and can accurately determine the content ratio of elements such as nickel, cobalt, manganese, lithium, etc. in the fine powder of ternary waste.

[0019] Optionally, the heating rate of the first sintering is 3-8°C / min; and / or the heating rate of the second sintering is 1-5°C / min.

[0020] By adopting the above technical solution, during the first sintering, the heating rate is controlled at 3-8°C / min to ensure that the various components in the ternary waste can be melted and diffused evenly, avoiding local overheating or uneven composition due to rapid temperature changes; at the same time, this heating rate can also effectively reduce the thermal stress that may be generated during the sintering process and reduce the risk of material cracking or deformation. During the second sintering, the heating rate is controlled at 1-5°C / min to further promote the chemical reaction and solid phase diffusion between the components in the ternary material, making the material more dense and uniform; at the same time, a slower heating rate can also reduce the tendency of grain growth, thereby obtaining a recycled high-nickel ternary material with better performance.

[0021] Optionally, the type of the waste ternary lithium battery is selected from 333, 433, 523 and 622.

[0022] By adopting the above technical scheme, 333, 433, 523 and 622 types of waste ternary lithium batteries are the main types of waste lithium batteries. The present invention recycles and reuses these waste low-nickel lithium batteries to obtain recycled high-nickel ternary materials with excellent performance, saving resources and reducing the cost of ternary lithium batteries.

[0023] In the second aspect, the present application provides a recycled high-nickel ternary material using the following technical solution: A regenerated high-nickel ternary positive electrode material is prepared by the preparation method of the invention.

[0024] By adopting the above technical scheme, after the waste lithium batteries are processed, a ternary material with a high nickel content is obtained. Since nickel can improve the activity of the material in the lithium battery, the increase in nickel content can increase the energy density of the battery, thereby increasing the battery capacity and the first efficiency. The recycled high-nickel ternary material is made into a ternary lithium battery, and its first discharge capacity can reach 211.7mAh / g, and the first efficiency can reach 89.0%, both reaching the level of standard ternary lithium batteries.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present invention can regenerate and repair the defects of ternary waste materials and obtain high-performance regenerated high-nickel ternary materials, thereby reducing the cost of ternary lithium batteries and facilitating the sustainable development of lithium-ion batteries; on the other hand, the preparation method is simple to operate, does not involve acid and alkali leaching and extraction recovery throughout the process, does not produce harmful substances, and avoids secondary pollution to the environment; 2.333, 433 and 523 types of waste ternary lithium batteries are the main types of waste lithium batteries. The present invention recycles and reuses these waste low-nickel lithium batteries to obtain recycled high-nickel ternary materials with excellent performance, saving resources and reducing the cost of ternary lithium batteries; 3. After processing, waste lithium batteries can obtain ternary materials with high nickel content. Since nickel can improve the activity of materials in lithium batteries, the increase in nickel content can increase the energy density of the battery, thereby increasing the battery capacity and initial efficiency. The recycled high-nickel ternary materials are made into ternary lithium batteries, and their initial discharge capacity can reach 211.7mAh / g, and the initial efficiency can reach 89.0%, both of which have reached the level of standard ternary lithium batteries. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to embodiments and comparative examples.

[0027] The types of waste ternary lithium batteries are selected from 333, 433, 523 and 622 types, and the waste lithium batteries in the following embodiments are selected from 523 type waste lithium batteries.

[0028] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified. Example

[0029] Example 1 The preparation method of the regenerated high-nickel ternary material provided in this embodiment comprises the following steps: S1. Sorting, discharging, disassembling and sorting the waste lithium batteries to obtain ternary waste, placing the ternary waste in an air atmosphere, pyrolyzing it at 500°C for 4 hours, and then subjecting the ternary waste after pyrolysis to ultrasonic treatment for 30 minutes, and sieving it with a 250-mesh sieve to obtain coarse particles of ternary waste; S2. crushing and sieving the coarse particles of the ternary waste in step S1 to obtain fine powder of the ternary waste; S3. Performing ICP detection on the step S2 to obtain the actual content ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder, and then adding nickel nitrate, cobalt hydroxide, manganese carbonate and lithium hydroxide to the ternary waste fine powder to adjust the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder to 8:1:1:0.95, and stirring and mixing for 4 hours to obtain a mixture; S4. In an oxygen-rich atmosphere, the mixture in step 3 was sintered twice, the temperature of the first sintering was 500 ° C, the heating rate was 7 ° C / min, and the holding time was 5 hours; after the first sintering, the temperature was then raised to 850 ° C for the second sintering, the heating rate was 3 ° C / min, and the holding time was 12 hours to obtain a sintered material; S5. Crush, screen and demagnetize the sintered material in step S4 to obtain a regenerated high-nickel ternary material.

[0030] Example 2 The difference between this embodiment and embodiment 1 is that the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder is adjusted to 8:1:1:1.00, and the remaining steps and components are the same as those in embodiment 1.

[0031] Example 3 The difference between this embodiment and embodiment 1 is that the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder is adjusted to 8:1:1:1.05, and the remaining steps and components are the same as those in embodiment 1.

[0032] Example 4 The difference between this embodiment and embodiment 1 is that the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder is adjusted to 8:1:1:1.10, and the remaining steps and components are the same as those in embodiment 1.

[0033] Example 5 The difference between this embodiment and embodiment 1 is that the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder is adjusted to 8:1:1:1.15, and the remaining steps and components are the same as those in embodiment 1.

[0034] Example 6 The difference between this embodiment and embodiment 4 is that nickel nitrate is replaced by nickel carbonate, cobalt hydroxide is replaced by cobalt carbonate, manganese carbonate is replaced by manganese acetate, and lithium hydroxide is replaced by lithium carbonate. The remaining steps and components are the same as those in embodiment 4.

[0035] Example 7 The difference between this embodiment and embodiment 4 is that nickel nitrate is replaced by nickel hydroxide, cobalt hydroxide is replaced by cobalt carbonate, manganese carbonate is replaced by manganese acetate, and lithium hydroxide is replaced by lithium acetate. The remaining steps and components are the same as those in embodiment 4.

[0036] Example 8 The difference between this embodiment and embodiment 4 is that nickel nitrate is replaced by nickel acetate, cobalt hydroxide is replaced by cobalt acetate, manganese carbonate is replaced by manganese acetate, lithium hydroxide is replaced by lithium oxalate, and the remaining steps and components are the same as those in embodiment 4.

[0037] Example 9 The difference between this embodiment and embodiment 4 is that nickel nitrate is replaced by nickel carbonate, cobalt hydroxide is replaced by cobalt acetate, manganese carbonate is replaced by manganese carbonate, and lithium hydroxide is replaced by lithium acetate. The remaining steps and components are the same as those in embodiment 4.

[0038] Example 10 The difference between this embodiment and embodiment 4 is that nickel nitrate is replaced by nickel acetate, cobalt hydroxide is replaced by cobalt acetate, manganese carbonate is replaced by manganese acetate, lithium hydroxide is replaced by lithium oxalate, and the remaining steps and components are the same as those in embodiment 4.

[0039] Comparative Example Comparative Example 1 The difference between this comparative example and Example 4 is that the ratio of nickel, cobalt, manganese and lithium in the ternary waste is not adjusted, that is, the operations of step 3 and step 4 are not performed, and the remaining steps and components are the same as Example 4.

[0040] Comparative Example 2 The difference between this comparative example and Example 4 is that the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder is adjusted to 5:2:3:1, and the remaining steps and components are the same as those in Example 4.

[0041] Comparative Example 3 The ternary material provided in this comparative example is selected from commercial NCM811, which is provided by Ningbo Rongbai New Energy Technology Co., Ltd.

[0042] The components and their proportions in Examples 1 to 10 and Comparative Examples 1 to 3 are shown in Table 1.

[0043] Table 1: Components and their proportions in Examples 1 to 10 and Comparative Examples 1 to 3 Performance Testing 1. The regenerated nickel cobalt manganese oxide positive electrode materials prepared in Examples 1 to 10 and Comparative Examples 1 to 3 were tested for particle size, tap density and specific surface area.

[0044] The name and model of the instrument used in the test are: Particle size, laser particle size distribution analyzer Mastersizer3000; Tap density, Better tap density tester; Specific surface area, fine and high JW~DX type; pH value: pH meter; Ni, Co, Mn, Li content: ICP test.

[0045] 2. The button cell test method was used to test the first discharge capacity and first efficiency of the regenerated nickel cobalt manganese oxide positive electrode materials in Examples 1 to 10 and Comparative Examples 1 to 3.

[0046] Button cell test method: Recycled high nickel ternary material, super P, and polyvinylidene fluoride are mixed and ground in a ratio of 8:1:1 and evenly coated on aluminum foil as the positive electrode, metal lithium sheet is the positive electrode, polypropylene porous membrane (celgard 2400) is the diaphragm, 1 mol / L LiPF6 is used as the electrolyte, and the solvent is composed of dimethyl carbonate, ethylene carbonate, and methyl carbonate in a volume ratio of 1:1:1. CR2032 button cells are assembled in a dry glove box filled with argon gas and tested using the Xinwei battery test system. The voltage range is 3.0-4.3V, and the charge and discharge rate is 0.2C. Test the first discharge capacity and first efficiency of the battery.

[0047] The test results are shown in Tables 2-3.

[0048] Table 2: Test data of Examples 1 to 10 and Comparative Examples 1 to 3 Table 3: Test data of Examples 1 to 10 and Comparative Examples 1 to 3 Referring to Tables 1 to 3, combined with the test results of Examples 1 to 10 and Comparative Example 3, it can be seen that the performance of the particles and the contents of nickel, cobalt, manganese and lithium elements of the recycled high-nickel ternary material prepared in the embodiments of the present invention have reached the level of commercial high-nickel ternary materials, that is, compared with the commercial 811 of Comparative Example 2; it can be seen that the preparation method of the present application can effectively repair the defects of low-nickel ternary waste and make recycled ternary materials with high nickel content, and the battery performance is also improved, with the first discharge capacity reaching more than 208.0 mAh / g and the first discharge efficiency reaching more than 87.5%, both reaching the level of standard high-nickel ternary lithium batteries.

[0049] By comparing Example 4 and Comparative Example 1, Comparative Example 1 did not add a metal source to the ternary waste to adjust the ratio of nickel, cobalt, manganese and lithium. It can be seen from the test data that its first discharge capacity and first charge and discharge efficiency are significantly reduced; it shows that adding a metal source to the ternary waste can replenish the metal elements lost in the waste, and adjust the ratio of nickel, cobalt, manganese and lithium in the ternary waste to meet the composition requirements for regenerating high-nickel ternary materials, thereby obtaining a high-nickel ternary lithium battery with better performance.

[0050] By comparing the test data of Examples 1 to 5, it can be seen that adjusting different lithium element ratios will affect the performance of the recycled high-nickel ternary material; when the ratio of nickel, cobalt, manganese and lithium in the recycled high-nickel ternary material is adjusted to 8:1:1:1.05, the performance of the battery is optimal; by adjusting the element ratio of the recycled high-nickel ternary material, high-quality and high-performance recycled high-nickel ternary material can be obtained to improve the performance of the battery.

[0051] In Examples 6 to 10, different nickel sources, cobalt sources, manganese sources and lithium sources are used to adjust the corresponding metal ratios in the ternary material. It can be seen from the test data that the battery performance of Examples 6 to 9 has reached the standard of commercial ternary lithium batteries; it further illustrates that selecting suitable nickel sources, cobalt sources, manganese sources and lithium sources is beneficial to adjusting the ratio of nickel, cobalt, manganese and lithium in the ternary waste, and impurities will not be introduced after addition, thereby affecting the performance of the regenerated high-nickel ternary material.

[0052] By comparing the test data of Example 4 and Comparative Example 2, it can be seen that Comparative Example 2 is a ternary material made by adopting different proportions of nickel, cobalt, manganese and lithium, and the ternary lithium battery prepared by the ternary material is type 523, while Example 4 prepares a high-nickel ternary material, which is significantly better than Comparative Example 2 in battery performance; this is because nickel can improve the activity of the material, so a higher content of nickel can significantly increase the energy density of the battery, thereby improving the battery's first discharge capacity and first charge and discharge efficiency, so as to meet the demand of new energy vehicles for high energy density batteries.

[0053] The present invention regenerates and repairs low-nickel ternary materials into high-nickel ternary materials. The repaired materials can further improve the performance of the battery, have great application prospects, and increase the recycling value of waste lithium batteries. In addition, the preparation method is simple to operate, does not involve acid-base leaching and extraction recovery throughout the process, does not produce harmful substances, and avoids secondary pollution to the environment.

[0054] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a regenerated high-nickel ternary material, characterized in that: The following steps are involved: S1. Classifying, discharging, disassembling and sorting the waste ternary lithium batteries to obtain ternary waste, pyrolyzing the ternary waste in an air atmosphere, ultrasonically treating the ternary waste after the pyrolysis treatment, and sieving to obtain coarse particles of the ternary waste; S2. crushing and sieving the coarse particles of the ternary waste in step S1 to obtain fine powder of the ternary waste; S3. Performing element determination on the ternary waste fine powder in step S2 to obtain the actual content ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder, and then adding a nickel source, a cobalt source, a manganese source and a lithium source to the ternary waste fine powder, adjusting the molar ratio of nickel, cobalt, manganese and lithium in the ternary waste fine powder to 8:1:1:0.95-1.15, and fully stirring and mixing for 3-5 hours to obtain a mixture; S4. The mixed material in step 3 is sintered twice, the temperature of the first sintering is 450-550°C, and the holding time is 4-6 hours; after the first sintering, the temperature is then raised to 750-900°C for the second sintering, and the holding time is 10-15 hours to obtain a sintered material; S5. Crush, screen and demagnetize the sintered material in step S4 to obtain a regenerated high-nickel ternary material.

2. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: In the step S1, the temperature of the pyrolysis treatment is 400-600° C., and the insulation time is 3-6 hours.

3. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: In the step S1, a sieve with a mesh size of 150 to 400 is used for screening.

4. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: The nickel source is selected from one of nickel acetate, nickel carbonate and nickel hydroxide; And / or, the cobalt source is selected from one of cobalt acetate, cobalt carbonate and cobalt hydroxide; And / or, the manganese source is selected from one of manganese carbonate and manganese acetate; And / or, the lithium source is selected from one of lithium carbonate, lithium hydroxide, lithium oxalate and lithium acetate.

5. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: In the step S4, sintering is performed in an oxygen-rich atmosphere.

6. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: In the step S3, ICP detection is used to perform element determination on the ternary waste fine powder.

7. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: The heating rate of the first sintering is 3-8°C / min; and / or the heating rate of the second sintering is 1-5°C / min.

8. The method for preparing a regenerated high-nickel ternary material according to claim 1, characterized in that: The type of the waste ternary lithium battery is selected from 333, 433, 523 and 622.

9. A recycled high-nickel ternary material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.

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