A method for reconstructing a positive electrode precursor from waste ternary positive electrode materials, and a positive electrode precursor
By combining in-situ co-precipitation with specific surfactants, the problems of complex traditional processes and irregular shapes of cathode precursors have been solved, enabling the preparation of cathode precursors with high tap density and sphericity, thus enhancing the application value of battery materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GEM CO LTD
- Filing Date
- 2026-04-21
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional wet recycling of ternary lithium-ion battery cathode materials is a complex process, resulting in cathode precursors with irregular shapes, low tap density, and limited application value.
An in-situ co-precipitation method was adopted to form a stable dispersion by mixing nonionic and cationic surfactants, control the reaction pH value, and then perform solid-liquid separation and washing after precipitation to prepare a spherical positive electrode precursor.
The process was simplified, resulting in a positive electrode precursor with high tap density and excellent sphericity, reducing surfactant residue and improving electrochemical performance.
Smart Images
Figure CN122380459A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery recycling technology, and in particular to a method for regenerating cathode precursors from waste ternary cathode materials, and cathode precursors. Background Technology
[0002] Ternary lithium-ion batteries are widely used in new energy vehicles and consumer electronics due to their high energy density and long cycle life. In recent years, with the rapid increase in the number of retired batteries, the recovery of high-value metals from spent ternary nickel-cobalt-manganese lithium batteries has significant economic and environmental implications.
[0003] Currently, traditional wet recycling and remanufacturing processes typically include steps such as acid leaching, purification, stepwise extraction, back-extraction, mixing, and co-precipitation, with the back-extraction process being quite complex. To simplify the process, researchers have attempted to co-precipitate the supported organic phase to directly obtain the cathode precursor, but the resulting cathode precursor has an irregular shape, low tap density, and limited application value. Summary of the Invention
[0004] To address the aforementioned issues, this application provides a method for regenerating cathode precursors from waste ternary cathode materials, as well as the cathode precursor itself. This method prepares the cathode precursor through in-situ co-precipitation, which is not only simple in process but also yields cathode precursors with excellent sphericity and tap density.
[0005] In a first aspect, this application provides a method for regenerating a cathode precursor from waste ternary cathode materials.
[0006] A method for regenerating cathode precursors from waste ternary cathode materials includes the following steps:
[0007] Acid leaching was performed on waste ternary cathode materials to prepare leachate;
[0008] The leachate was co-extracted using an extractant to prepare an organic-supported liquid;
[0009] The organic supported liquid and the stabilizer are mixed to prepare a dispersion, wherein the stabilizer includes a surfactant and water, and the surfactant includes a nonionic surfactant and a cationic surfactant.
[0010] The precipitant, complexing agent, and dispersion are passed into the reaction substrate, and the pH of the reaction system is controlled at 10.5-12. After co-precipitation treatment, a co-precipitation system is obtained.
[0011] The coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor, which is then washed to prepare the cathode precursor.
[0012] In some embodiments, the surfactant in the dispersion accounts for 0.5% to 3% by mass, and the mass ratio of the nonionic surfactant to the cationic surfactant is (2 to 5):1.
[0013] In some embodiments, the stabilizer comprises, by mass percentage:
[0014] The composition includes 0.5% to 3.5% nonionic surfactant, 0.2% to 1.5% cationic surfactant, and 95% to 99.3% water; wherein the nonionic surfactant includes Tween 80, and the cationic surfactant includes hexadecyltrimethylammonium bromide.
[0015] In some embodiments, the coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor;
[0016] The solid phase was countercurrently washed using an ethanol aqueous solution with a volume fraction of 40%~60% at 40℃~60℃, and then dried to obtain the positive electrode precursor.
[0017] In some embodiments, the total ion concentration of nickel ions, cobalt ions, and manganese ions in the dispersion is 2.2 mol / L to 2.8 mol / L.
[0018] In some embodiments, the precipitant comprises 4.8 mol / L to 5.2 mol / L NaOH, and the complexing agent comprises 4 mol / L to 6 mol / L NH3·H2O and 0.5 mol / L to 1 mol / L (NH4)2SO4;
[0019] During the coprecipitation treatment, the flow rate ratio of the dispersion, the complexing agent, and the precipitant is 1:(0.3~0.5):(0.75~0.85), and the flow rate ratio of the dispersion to the sum of the flow rates of the complexing agent and the precipitant is 1:(1.05~1.35).
[0020] In some embodiments, the extractant comprises, by volume fraction:
[0021] P507 15%~30%, tributyl phosphate 5%~10%, and sulfonated kerosene 60%~80%.
[0022] In some embodiments, the step of acid leaching the waste ternary cathode material includes:
[0023] Waste ternary cathode materials are roasted and pulverized to prepare cathode powder.
[0024] The positive electrode powder is subjected to acid leaching to prepare a first acid leaching solution;
[0025] The first acid leaching solution is subjected to precipitation to remove impurities and then filtered to obtain a leachate.
[0026] In some embodiments, the precipitation and impurity removal step includes:
[0027] The pH of the first acid leaching solution was adjusted to 4.4-4.8 using sodium hydroxide solution, and the solid and liquid were separated to obtain the second acid leaching solution.
[0028] The second acid leaching solution is mixed with calcium salt, and the solid and liquid are separated to obtain the leachate.
[0029] In a second aspect, this application provides a positive electrode precursor obtained by the method described above.
[0030] Compared with traditional solutions, this application has the following advantages:
[0031] The method for regenerating cathode precursors from waste ternary cathode materials provided in this application involves mixing a co-extracted organic loading liquid with a specific stabilizer to form a dispersion. After co-precipitation, a cathode precursor with high tap density can be obtained in situ. The stabilizer, by incorporating both nonionic and cationic surfactants, effectively reduces the oil-water interfacial tension in the dispersion, thereby dispersing the organic loading liquid into stable microdroplets. This provides a more stable reaction interface for metal ion precipitation, resulting in uniform growth of the cathode precursor and increased tap density. Specifically, the nonionic surfactant provides good steric stabilization, while the cationic surfactant enhances the interfacial film strength through electrostatic interactions. The combination of these two surfactants forms a semi-permeable interfacial film, allowing OH-... - It can easily penetrate the interface and react with metal ions to generate crystal nuclei, and can also quickly dissociate and desorb during the washing stage to avoid residues. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a flowchart illustrating a method for preparing a cathode precursor from recycled ternary cathode materials according to one embodiment of this application. Detailed Implementation
[0034] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0035] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this application, "at least one" means one or more, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0037] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.
[0038] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0039] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.
[0040] Unless otherwise specified, the viscosity parameters used in this application refer to the viscosity measured at 25°C.
[0041] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.
[0042] In a first aspect, this application provides a method for regenerating cathode precursors from waste ternary cathode materials. This method prepares cathode precursors through in-situ co-precipitation, which is not only simple in process, but also produces cathode precursors with excellent elemental distribution uniformity and tap density.
[0043] For example, please see Figure 1 , Figure 1 This is a flowchart of a method for regenerating a cathode precursor from waste ternary cathode materials according to one embodiment of this application.
[0044] A method for regenerating cathode precursors from waste ternary cathode materials includes the following steps:
[0045] S1. Acid leaching of waste ternary cathode materials to prepare leachate;
[0046] S2. Co-extract the leachate using an extractant to prepare an organic loading solution.
[0047] S3. Mix the organic supported liquid and the stabilizer to prepare a dispersion. The stabilizer includes a surfactant and water. The surfactant includes nonionic surfactants and cationic surfactants.
[0048] S4. The precipitant, complexing agent and the dispersion are introduced into the reaction substrate, and the pH of the reaction system is controlled to be 10.5~12. The coprecipitation system is obtained by coprecipitation treatment. It can be understood that the pH of the reaction system refers to the pH of the aqueous phase.
[0049] S5. Perform solid-liquid separation on the coprecipitation system to obtain a solid precursor, wash the solid precursor, and prepare the cathode precursor.
[0050] The above method involves mixing the co-extracted organic loading solution with a specific stabilizer to form a dispersion. After co-precipitation, a cathode precursor with high tap density can be obtained in situ. The stabilizer, by combining nonionic and cationic surfactants, effectively reduces the oil-water interfacial tension in the dispersion, thereby dispersing the organic loading solution into stable microdroplets. This provides a more stable reaction interface for metal ion precipitation, resulting in uniform growth of the cathode precursor and increased tap density. Specifically, the nonionic surfactant provides good steric stabilization, while the cationic surfactant enhances the interfacial film strength through electrostatic interactions. The combination of these two surfactants forms a semi-permeable interfacial film, allowing OH-... - It can easily penetrate the interface and react with metal ions to generate crystal nuclei, and can also quickly dissociate and desorb during the washing stage to avoid residues.
[0051] In some embodiments, the surfactant in the dispersion accounts for 0.5% to 3% by mass, and the mass ratio of nonionic surfactant to cationic surfactant is (2 to 5): 1.
[0052] Optionally, the mass ratio of the nonionic surfactant to the cationic surfactant can be, but is not limited to, 2:1, 3:1, 4:1, 5:1, or other values within the range of (2~5):1. Maintaining the addition amounts of both within the above range is more conducive to the formation of a high-performance interfacial film. This not only disperses the organic supported liquid into fine, uniform, and stable droplets, but also enhances the reactivity between metal ions and the precipitant, and enables rapid dissociation and desorption during the washing stage to avoid residue.
[0053] Optionally, the mass percentage of the surfactant in the dispersion can be, but is not limited to, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or other values within the range of 0.5% to 3%. In this embodiment, through the compounding effect of different surfactants in specific proportions, the resulting interfacial film can provide a high-quality reaction interface for the precipitation reaction, allowing the total amount of surfactant to be maintained at a low level. This helps to effectively reduce surfactant residue in the cathode precursor, thereby reducing the residual carbon content of the obtained cathode precursor and improving the electrochemical performance of the cathode precursor.
[0054] In some embodiments, the content of cationic surfactant in the stabilized solution is 0.2% to 1.5% by mass percentage. Optionally, the content of cationic surfactant in the stabilized solution can be, but is not limited to, 0.2%, 0.5%, 0.7%, 1%, 1.1%, 1.3%, 1.5%, or other values within the range of 0.2% to 1.5%.
[0055] In some embodiments, the stabilizer comprises, by mass percentage:
[0056] The composition includes 0.5% to 3.5% nonionic surfactants, 0.2% to 1.5% cationic surfactants, and 95% to 99.3% water; among which, nonionic surfactants include Tween 80, and cationic surfactants include hexadecyltrimethylammonium bromide.
[0057] In this embodiment, Tween 80 and hexadecyltrimethylammonium bromide are used synergistically to form a composite surfactant system that can effectively reduce surface tension. Tween 80, with its long-chain fatty acid structure, has good steric stabilizing properties, primarily used to reduce oil-water interfacial tension. Simultaneously, hexadecyltrimethylammonium bromide can adsorb onto the surface of organic-supported liquid droplets, imparting surface charge to the droplets, thereby maintaining the stability of the dispersion system and preventing element aggregation.
[0058] In some embodiments, the mixing mass ratio of the organic supported liquid to the stabilized liquid is 1:(3~8) when preparing the dispersion. Optionally, the mixing mass ratio of the organic supported liquid to the stabilized liquid can be, but is not limited to, other values within the range of 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:(3~8).
[0059] In some embodiments, the total ion concentration of nickel, cobalt, and manganese ions in the dispersion is 2.2 mol / L to 2.8 mol / L. Optionally, the total ion concentration of nickel, cobalt, and manganese ions in the dispersion can be, but is not limited to, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.7 mol / L, 2.8 mol / L, or other values within the range of 2.2 mol / L to 2.8 mol / L. Controlling the total ion concentration within the above range and dispersing it together with the stabilizer in the above proportions can achieve good dispersion results.
[0060] In some embodiments, the precipitant includes 4.8 mol / L to 5.2 mol / L NaOH, and the complexing agent includes 4 mol / L to 6 mol / L NH3·H2O and 0.5 mol / L to 1 mol / L (NH4)2SO4. During co-precipitation, the flow rate ratio of the dispersion, complexing agent, and precipitant is 1:(0.3~0.5):(0.75~0.85), and the flow rate ratio of the dispersion to the sum of the flow rates of the complexing agent and the precipitant is 1:(1.05~1.35). By using the above-mentioned mixed flow rate ratio of dispersion, complexing agent, and precipitant during co-precipitation, and maintaining the pH within a certain range, the solubility product differences of metal hydroxides can be effectively balanced, thereby obtaining a hydroxide-type cathode precursor with good sphericity and uniform particle size distribution.
[0061] In some embodiments, a co-precipitation treatment is performed at 50°C to 85°C under an inert gas atmosphere. Optionally, the inert gas includes nitrogen. Performing the above precipitation reaction under an inert gas atmosphere helps to prevent the oxidation of manganese.
[0062] In some embodiments, the coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor;
[0063] The solid phase was countercurrently washed using an ethanol aqueous solution with a volume fraction of 40%~60% at 40℃~60℃, and then dried to obtain the positive electrode precursor.
[0064] Studies have shown that using ethanol to reduce the surface tension of water and dissolve the organic phase, while simultaneously disrupting surfactant micelles, can efficiently desorb surfactants from solid surfaces. Maintaining an ethanol volume fraction of 40% to 60% further enhances the desorption effect.
[0065] In some embodiments, the solid-liquid mass ratio of countercurrent washing is 1:(3~5).
[0066] In some embodiments, the temperature of the countercurrent washing is 40°C to 60°C.
[0067] In some embodiments, the drying method is vacuum drying. Optionally, the vacuum drying temperature is 90℃~120℃, and the vacuum degree of vacuum drying is ≤-0.08MPa.
[0068] In some embodiments, the extractant includes P507 and tributyl phosphate. Studies have shown that the composite extraction system using P507 and tributyl phosphate can effectively enhance the extraction capacity for manganese by utilizing tributyl phosphate, and effectively reduce the differences in extraction rates of nickel, cobalt, and manganese by different extractants.
[0069] In some embodiments, the extractant comprises, by volume fraction:
[0070] P507 15%~30%, tributyl phosphate 5%~10%, and sulfonated kerosene 60%~80%.
[0071] Optionally, the content of P507, by volume fraction, can be, but is not limited to, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, or other values within the range of 15% to 30%.
[0072] Optionally, the content of tributyl phosphate, by volume fraction, can be, but is not limited to, 5%, 6%, 7%, 8%, 9%, 10%, or other values within the range of 5% to 10%.
[0073] In some embodiments, the pH of the leachate is adjusted to 4.4-4.8 using sodium hydroxide solution. Studies have shown that, based on the co-extraction system of P507 and tributyl phosphate described above, the Mn extraction rate is too low at excessively low pH, while excessively high pH results in serious impurity co-extraction problems. Maintaining the pH of the leachate within the aforementioned range minimizes the difference in co-extraction rates of nickel, cobalt, and manganese, achieving good simultaneous extraction of nickel, cobalt, and manganese, and preserving the original elemental proportions of the organic loading solution as much as possible.
[0074] In some embodiments, the co-extraction process includes:
[0075] A three-stage countercurrent mixing and clarification tank is used, in which the extractant and leachate are continuously stirred at 300 rpm to 500 rpm at a volume flow ratio of (0.8~1.5):1, at 40℃~50℃, and the residence time of each stage is controlled to be 7 min / stage to 10 min / stage.
[0076] In some embodiments, the step of acid leaching the waste ternary cathode material includes:
[0077] Waste ternary cathode materials are roasted and pulverized to prepare cathode powder.
[0078] The cathode powder is acid-leached to prepare the first acid leaching solution;
[0079] The first acid leaching solution is subjected to precipitation to remove impurities and then filtered to obtain the leachate.
[0080] In this embodiment, the waste ternary cathode material is calcined to remove excess binder and carbon material. Optionally, the calcination temperature is 500℃~600℃, and the calcination time is 1.5h~3h.
[0081] In this embodiment, pulverization is used to improve the efficiency of subsequent acid leaching of the cathode powder. Optionally, the D50 of the pulverized cathode powder is less than 75 μm.
[0082] In some embodiments, the acid leaching step includes:
[0083] The positive electrode powder is mixed with the acid leaching solution and stirred at 60℃~90℃ for 2h~5h. Solid-liquid separation is then performed to obtain the first acid leaching solution.
[0084] In some embodiments, the acid leaching solution comprises 1 mol / L to 2 mol / L of H2SO4 and 5 wt% to 10 wt% of Na2SO3.
[0085] In some embodiments, the solid-liquid ratio of the positive electrode powder to the acid leaching solution is 1:(5~10).
[0086] In some embodiments, the precipitation and impurity removal step includes:
[0087] The pH of the first acid leaching solution was adjusted to 4.4-4.8 using sodium hydroxide solution, and the solid and liquid were separated to obtain the second acid leaching solution.
[0088] The second acid leaching solution is mixed with calcium salt, and the solid and liquid are separated to obtain the leachate.
[0089] In this embodiment, the pH is adjusted by sodium hydroxide solution to precipitate iron and aluminum ion impurities in the first acid leaching solution; and calcium salt is added to precipitate fluoride ion impurities in the first acid leaching solution.
[0090] Optionally, the mass concentration of the sodium hydroxide solution is 5% to 15%.
[0091] Optionally, the calcium salt includes calcium chloride, and the amount added can be from 0.5 g / L to 2 g / L.
[0092] In some embodiments, the liquid phase obtained from the solid-liquid separation of the coprecipitation system is centrifuged to obtain a composite organic phase;
[0093] Add 0.05%~0.2% of polyether-modified siloxane by volume to the composite organic phase, allow it to stand at 60℃~80℃ to separate into layers, retain the upper layer, and obtain the purified organic phase.
[0094] In this embodiment, the liquid phase product after solid-liquid separation is subjected to secondary separation and demulsification purification. The resulting purified organic phase can be used as a raw material for the extractant, thus achieving recycling.
[0095] In a second aspect, this application provides a positive electrode precursor obtained by the method described above.
[0096] In some embodiments, the residual carbon content of the cathode precursor is 0.03% to 0.15%.
[0097] In some embodiments, the tap density of the positive electrode precursor is 2.1 g / cm³. 3 ~2.2g / cm 3 .
[0098] The present application will be further described in detail below with reference to specific embodiments.
[0099] Unless otherwise specified, the raw materials used in the following specific embodiments and comparative examples are all commercially available products; the instruments used are all commercially available products; and the processes used are all conventionally selected by those skilled in the art unless otherwise specified.
[0100] Example 1
[0101] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0102] The preparation method of the positive electrode precursor is as follows:
[0103] S1. Using the cathode powder from retired NCM622 electric vehicle batteries as waste ternary cathode material, the waste ternary cathode material is roasted and crushed to obtain cathode powder. The cathode powder is mixed with acid leaching solution at a ratio of 1kg:3L and stirred at 75℃ for 3h. Solid-liquid separation is performed, and the pH is adjusted to 4.8 with sodium hydroxide solution. The supernatant is then separated by centrifugation to obtain leachate. The acid leaching solution contains 2mol / L H2SO4, 8wt% Na2SO3 and the remainder water.
[0104] S2. Using a three-stage countercurrent mixing and clarification tank, the extractant and leachate are mixed at a volume flow ratio of 1.5:1 at 48℃, and the residence time of each stage is controlled to be 8 min to obtain an organic loading solution. The total ion concentration of nickel, cobalt, and manganese ions in the organic loading solution is adjusted to 2.5 mol / L using the extractant. The extractant contains 16 vol% P507, 6 vol% tributyl phosphate, and the balance sulfonated kerosene.
[0105] S3. Mix and disperse the organic supporting liquid and the stabilizing liquid to obtain a dispersion; wherein the stabilizing liquid contains 1.35% Tween 80, 0.65% hexadecyltrimethylammonium bromide and the balance water, and the mixing ratio of the organic supporting liquid and the stabilizing liquid is 1:6.
[0106] S4. Prepare the reaction base solution. Stir the reaction base solution continuously at 300 rpm. Under nitrogen protection and at 60°C, introduce the precipitant, complexing agent and dispersion into the reaction base solution. Control the pH of the reaction system to be about 8.5. Continue stirring for 30 min and then continue stirring for 20 min to obtain the coprecipitation system.
[0107] The flow rate ratio of the dispersion, complexing agent, and precipitant is 1:0.4:0.8. The precipitant contains 5.0 mol / L NaOH, and the complexing agent contains 5.0 mol / L NH3·H2O and 0.8 mol / L (NH4)2SO4.
[0108] S5. The coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor. The solid precursor is then washed countercurrently with a 50 vol% ethanol aqueous solution at 50 °C, followed by countercurrent washing with pure water. After vacuum drying, the positive electrode precursor is obtained.
[0109] Example 2
[0110] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0111] The preparation method of the positive electrode precursor is as follows:
[0112] S1. Using the cathode powder from retired NCM622 electric vehicle batteries as waste ternary cathode material, the waste ternary cathode material is roasted and crushed to obtain cathode powder. The cathode powder is mixed with acid leaching solution at a ratio of 1kg:3L and stirred at 75℃ for 3h. Solid-liquid separation is performed, and the pH is adjusted to 4.6 with sodium hydroxide solution. The supernatant is then separated by centrifugation to obtain leachate. The acid leaching solution contains 2mol / L H2SO4, 8wt% Na2SO3 and the remainder is water.
[0113] S2. Using a three-stage countercurrent mixing and clarification tank, the extractant and leachate are mixed at a volume flow ratio of 1.5:1 at 48℃, and the residence time of each stage is controlled to be 8 min to obtain an organic loading solution. The total ion concentration of nickel, cobalt, and manganese ions in the organic loading solution is adjusted to 2.2 mol / L using the extractant. The extractant contains 24 vol% P507, 10 vol% tributyl phosphate, and the balance sulfonated kerosene.
[0114] S3. Mix and disperse the organic supporting liquid and the stabilizing liquid to obtain a dispersion; wherein the stabilizing liquid contains 1.35% Tween 80, 0.65% hexadecyltrimethylammonium bromide and the balance water, and the mixing ratio of the organic supporting liquid and the stabilizing liquid is 1:6.
[0115] S4. Prepare the reaction base solution. Stir the reaction base solution continuously at 300 rpm. Under nitrogen protection and at 60°C, introduce the precipitant, complexing agent and dispersion into the reaction base solution. Control the pH of the reaction system to be about 8.5. Continue stirring for 30 min and then continue stirring for 20 min to obtain the coprecipitation system.
[0116] The flow rate ratio of the dispersion, complexing agent, and precipitant is 1:0.3:0.85. The precipitant contains 5.2 mol / L NaOH, and the complexing agent contains 6 mol / L NH3·H2O and 0.5 mol / L (NH4)2SO4.
[0117] S5. The coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor. The solid precursor is countercurrently washed with a 60 vol% ethanol aqueous solution at 40 °C, followed by countercurrent washing with pure water, and then vacuum dried to obtain the positive electrode precursor.
[0118] Example 3
[0119] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0120] The preparation method of the positive electrode precursor is as follows:
[0121] S1. Using the cathode powder from retired NCM622 electric vehicle batteries as waste ternary cathode material, the waste ternary cathode material is roasted and crushed to obtain cathode powder. The cathode powder is mixed with acid leaching solution at a ratio of 1kg:3L and stirred at 75℃ for 3h. Solid-liquid separation is performed, and the pH is adjusted to 4.4 with sodium hydroxide solution. The supernatant is then separated by centrifugation to obtain leachate. The acid leaching solution contains 2mol / L H2SO4, 8wt% Na2SO3 and the remainder water.
[0122] S2. Using a three-stage countercurrent mixing and clarification tank, the extractant and leachate are mixed at a volume flow ratio of 1.5:1 at 48℃, and the residence time of each stage is controlled to be 8 min to obtain an organic loading solution. The total ion concentration of nickel, cobalt, and manganese ions in the organic loading solution is adjusted to 2.8 mol / L using the extractant. The extractant contains 30 vol% P507, 5 vol% tributyl phosphate, and the balance sulfonated kerosene.
[0123] S3. Mix and disperse the organic supporting liquid and the stabilizing liquid to obtain a dispersion; wherein the stabilizing liquid contains 1.35% Tween 80, 0.65% hexadecyltrimethylammonium bromide and the balance water, and the mixing ratio of the organic supporting liquid and the stabilizing liquid is 1:7.
[0124] S4. Prepare the reaction base solution. Stir the reaction base solution continuously at 300 rpm. Under nitrogen protection and at 60°C, introduce the precipitant, complexing agent and dispersion into the reaction base solution. Control the pH of the reaction system to be about 8.5. Continue stirring for 30 min and then continue stirring for 20 min to obtain the coprecipitation system.
[0125] The flow rate ratio of the dispersion, complexing agent, and precipitant is 1:0.5:0.75. The precipitant contains 4.8 mol / L NaOH, and the complexing agent contains 4 mol / L NH3·H2O and 1 mol / L (NH4)2SO4.
[0126] S5. The coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor. The solid precursor is countercurrently washed with a 40 vol% ethanol aqueous solution at 60 °C, followed by countercurrent washing with pure water, and then vacuum dried to obtain the positive electrode precursor.
[0127] Example 4
[0128] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0129] The difference from Example 1 is that the stabilized solution contains 1.6% Tween 80, 0.4% cetyltrimethylammonium bromide, and the balance water.
[0130] Example 5
[0131] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0132] The difference from Example 1 is that the stabilizer contains 2.5% Tween 80, 1% cetyltrimethylammonium bromide, and the balance is water.
[0133] Example 6
[0134] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0135] The difference compared to Example 1 is as follows:
[0136] The stabilizer contains 4.5% Tween 80, 1.8% cetyltrimethylammonium bromide, and the balance water.
[0137] Example 7
[0138] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0139] The difference from Example 1 is that the stabilizer contains 1% Tween 80, 1% cetyltrimethylammonium bromide, and the balance is water.
[0140] Example 8
[0141] This embodiment provides a cathode precursor obtained by remanufacturing waste ternary cathode materials.
[0142] The difference from Example 1 is that the stabilized solution contains 0.67% Tween 80, 1.33% cetyltrimethylammonium bromide, and the balance water.
[0143] Example 9
[0144] This comparative example provides a cathode precursor obtained by remanufacturing waste ternary cathode material.
[0145] The difference from Example 1 is that the solid precursor was washed countercurrently with a 10% ethanol solution.
[0146] Comparative Example 1
[0147] This comparative example provides a cathode precursor obtained by remanufacturing waste ternary cathode material.
[0148] The difference compared to Example 1 is as follows:
[0149] The stabilizing solution contains 2% Tween 80 and the remainder is water.
[0150] Comparative Example 2
[0151] This comparative example provides a cathode precursor obtained by remanufacturing waste ternary cathode material.
[0152] The difference compared to Example 1 is as follows:
[0153] The stabilizing solution contains 2% cetyltrimethylammonium bromide and the remainder is water.
[0154] Comparative Example 3
[0155] This comparative example provides a cathode precursor obtained by remanufacturing waste ternary cathode material.
[0156] The difference compared to Example 1 is as follows:
[0157] The stabilizing solution contains 5% Tween 80 and the remainder is water.
[0158] Test case
[0159] The tap density, D50, and sphericity of the cathode precursors of the examples and comparative examples were tested, and the residual carbon content was tested according to the following method. The specific test results are shown in Table 1.
[0160] Residual carbon content: Using standard samples with carbon contents of 0.05%, 0.10%, and 0.20% to calibrate the curve, 0.2g of the positive electrode precursor was placed in a ceramic crucible and burned in a high-frequency induction furnace at 1300℃ with oxygen for 120s. The concentration of CO2 generated was detected by infrared spectroscopy and the residual carbon content was calculated.
[0161] Table 1. Test results of the examples and comparative examples.
[0162]
[0163] As can be seen from Table 1, by comparing Examples 1-9 and Comparative Examples 1-3, it can be seen that by using a combination of specific nonionic and cationic surfactants to prepare dispersions, a stable reaction interface with excellent reactivity can be formed, thereby enabling the in-situ preparation of hydroxide-type cathode precursors with excellent sphericity and tap density.
[0164] As can be seen from the comparison of Examples 1 to 8, by controlling the mass ratio of nonionic surfactant and cationic surfactant within a specific range, it is more conducive to forming an interface film with good semi-permeability. While maintaining the uniformity of the interface precipitation reaction, it further reduces the residual carbon content in the obtained positive electrode precursor and improves the sphericity, so that the positive electrode precursor has better electrical performance.
[0165] As can be seen from the comparison of Examples 1 to 6, within a certain range, keeping the amount of surfactant added relatively low is more conducive to obtaining a positive electrode precursor with high tap density, low residual carbon content, and high sphericity. This is because too much surfactant will lead to an overly strong interfacial film, which is not conducive to the reaction and elution.
[0166] As can be seen from the comparison of Examples 1-3 and Example 9, washing the separated solid phase with an ethanol aqueous solution within a specific volume fraction range is more helpful in removing organic impurities from the cathode precursor, thereby obtaining a cathode precursor with low residual carbon content.
[0167] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0168] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.
Claims
1. A method for regenerating cathode precursors from waste ternary cathode materials, characterized in that, Includes the following steps: Acid leaching was performed on waste ternary cathode materials to prepare leachate; The leachate was co-extracted using an extractant to prepare an organic-supported liquid; The organic supported liquid and the stabilizer are mixed to prepare a dispersion, wherein the stabilizer includes a surfactant and water, and the surfactant includes a nonionic surfactant and a cationic surfactant. The precipitant, complexing agent, and dispersion are passed into the reaction substrate, and the pH of the reaction system is controlled at 10.5-12. After co-precipitation treatment, a co-precipitation system is obtained. The coprecipitation system is subjected to solid-liquid separation to obtain a solid precursor, which is then washed to prepare the cathode precursor.
2. The method for regenerating cathode precursors from waste ternary cathode materials according to claim 1, characterized in that, The surfactant in the dispersion accounts for 0.5% to 3% of the total mass, and the mass ratio of the nonionic surfactant to the cationic surfactant is (2 to 5):
1.
3. The method for regenerating cathode precursors from waste ternary cathode materials according to claim 2, characterized in that, The stabilizer comprises, by mass percentage: The composition includes 0.5% to 3.5% nonionic surfactant, 0.2% to 1.5% cationic surfactant, and 95% to 99.3% water; wherein the nonionic surfactant includes Tween 80, and the cationic surfactant includes hexadecyltrimethylammonium bromide.
4. The method for regenerating a cathode precursor from waste ternary cathode material according to claim 1, characterized in that, The coprecipitation system was subjected to solid-liquid separation to obtain a solid precursor; The solid phase was countercurrently washed using an ethanol aqueous solution with a volume fraction of 40%~60% at 40℃~60℃, and then dried to obtain the positive electrode precursor.
5. The method for regenerating a cathode precursor from waste ternary cathode material according to claim 1, characterized in that, The total ion concentration of nickel, cobalt, and manganese ions in the dispersion is 2.2 mol / L to 2.8 mol / L.
6. The method for regenerating a cathode precursor from waste ternary cathode material according to claim 5, characterized in that, The precipitant comprises 4.8 mol / L to 5.2 mol / L NaOH, and the complexing agent comprises 4 mol / L to 6 mol / L NH3·H2O and 0.5 mol / L to 1 mol / L (NH4)2SO4; During the coprecipitation treatment, the flow rate ratio of the dispersion, the complexing agent, and the precipitant is 1:(0.3~0.5):(0.75~0.85), and the flow rate ratio of the dispersion to the sum of the flow rates of the complexing agent and the precipitant is 1:(1.05~1.35).
7. The method for regenerating a cathode precursor from waste ternary cathode material according to any one of claims 1 to 6, characterized in that, The extractant comprises, by volume fraction: P507 15%~30%, tributyl phosphate 5%~10%, and sulfonated kerosene 60%~80%.
8. The method for regenerating a cathode precursor from waste ternary cathode material according to any one of claims 1 to 6, characterized in that, The steps for acid leaching waste ternary cathode materials include: Waste ternary cathode materials are roasted and pulverized to prepare cathode powder. The positive electrode powder is subjected to acid leaching to prepare a first acid leaching solution; The first acid leaching solution is subjected to precipitation to remove impurities and then filtered to obtain a leachate.
9. The method for regenerating a cathode precursor from waste ternary cathode material according to claim 8, characterized in that, The steps for precipitation and impurity removal include: The pH of the first acid leaching solution was adjusted to 4.4-4.8 using sodium hydroxide solution, and the solid and liquid were separated to obtain the second acid leaching solution. The second acid leaching solution is mixed with calcium salt, and the solid and liquid are separated to obtain the leachate.
10. A positive electrode precursor, characterized in that, Obtained by the method described in any one of claims 1 to 9.