Cathode material precursor and preparation method thereof

Abstract

The application relates to the technical field of battery positive electrode materials, in particular to a positive electrode material precursor and a preparation method thereof. The positive electrode material precursor comprises primary particles and secondary particles; the primary particles are a combination of transition metal oxide particles and a chelating agent, and the secondary particles are an agglomerate of at least two primary particles; and the chelating agent is a chelating agent with at least one carboxyl group. The positive electrode material precursor has high compactness, uniform element distribution and expected particle size, and the slurry viscosity cannot be increased during the preparation process, so that the subsequent drying process can be smoothly carried out.

Description

Technical Field

[0001] This application relates to the field of battery cathode material technology, specifically to cathode material precursors and their preparation methods. Background Technology

[0002] In recent years, due to the rapid development of clean energy, society has placed higher demands on rechargeable batteries. As a core component of rechargeable batteries, the cost and performance of cathode materials directly constrain the research and application of rechargeable batteries.

[0003] Among cathode materials, a common type is various transition metal oxides. The traditional processes for producing these cathode materials mainly include liquid-phase and solid-phase methods. The traditional liquid-phase method involves dissolving a soluble salt of the target element in a liquid solvent, mixing it thoroughly, and then precipitating it from the solution to form granules. However, this method is more expensive than the solid-phase method and easily generates a large amount of waste liquid, causing environmental pressure.

[0004] Compared to traditional liquid-phase methods, traditional solid-phase methods have advantages such as lower cost and less environmental impact. However, this method suffers from problems such as uneven particle size, difficulty in controlling particle size, and loose, brittle particles. To address these issues, additives such as stabilizers are typically used to increase the viscosity of the solid-liquid mixture. However, increasing the viscosity of the slurry increases the difficulty of subsequent processing and carries the risk of introducing impurities. Furthermore, this method struggles to address the problem of uneven distribution of secondary particle elements. Summary of the Invention

[0005] In view of this, the present invention provides a cathode material precursor and a method for preparing the same. This cathode material precursor has high density, uniform element distribution, and particle size as expected. Furthermore, it does not increase the viscosity of the slurry during preparation, which is beneficial for the smooth implementation of subsequent drying processes.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a cathode material precursor, which includes primary particles and secondary particles; the primary particles are a complex formed by transition metal oxide particles combining with carboxyl groups in a chelating agent, and the secondary particles are an agglomeration of at least two primary particles.

[0008] The chelating agent is a chelating agent having at least two carboxyl groups.

[0009] Preferably, the median particle size D of the transition metal oxide particles is... 50 The wavelength range is 20~60nm.

[0010] In this embodiment of the invention, the median particle size D of the transition metal oxide particles is... 50 The wavelength is 30~50nm.

[0011] As a preferred option, the median particle size D of the cathode material precursor is... 50 The range is 200~800nm.

[0012] In this embodiment of the invention, the median particle size D of the cathode material precursor is... 50 The wavelength range is 250~750nm.

[0013] In embodiments of the present invention, the chelating agent includes a first chelating agent and / or a second chelating agent;

[0014] The first chelating agent is an aminocarboxylic acid chelating agent;

[0015] The second chelating agent is a chelating agent having the general formula shown in Formula I:

[0016]

[0017] Formula I

[0018] Among them, R1 is selected from C 1-10 Alkyl or phenyl groups. Preferably C 1-4 Straight-chain alkyl or phenyl groups.

[0019] In specific embodiments of the present invention, the first chelating agent includes, but is not limited to, at least one of iminodiacetic acid (IDA), nitrotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA).

[0020] In specific embodiments of the present invention, the second chelating agent includes, but is not limited to, at least one of phosphorylated acetic acid (PAA), 3-phosphorylated propionic acid (CEPA), 4-phosphorylated butyric acid (APPA), 5-phosphorylated valerate (APA), and p-carboxyphenylphosphonic acid (CPPA).

[0021] In this embodiment of the invention, in a primary particle, the number of carboxyl groups of the chelating agent is n, and the number of transition metal oxide particles bound to the chelating agent is ≤ n.

[0022] In embodiments of the present invention, transition metal oxides include, but are not limited to, at least one of iron oxides, manganese oxides, nickel oxides, titanium oxides, vanadium oxides, chromium oxides, cobalt oxides, copper oxides, and zinc oxides. For example, iron oxides include at least one of ferrous oxide (FeO), iron oxide (Fe2O3), and magnetite (Fe3O4); manganese oxides include at least one of manganese oxide (MnO), manganese dioxide (MnO2), manganese trioxide (Mn2O3), and manganese trioxide (Mn3O4); and nickel oxides include at least one of nickel oxide (NiO), nickel trioxide (Ni2O3), and nickel trioxide (Ni3O4).

[0023] Secondly, the present invention provides a solid-state preparation method for the above-mentioned cathode material precursor, comprising the following steps:

[0024] Transition metal oxide raw materials are milled to obtain a median particle size D. 50 The transition metal oxide particles are 20~60nm in size. The transition metal oxide particles are mixed with water to obtain a suspension.

[0025] The chelating agent is mixed with water to obtain a chelating agent solution;

[0026] The suspension was mixed with a chelating agent solution and stirred at high speed. The solid was then separated and dried to obtain a powder with a median particle size D. 50 It is a precursor for cathode materials with a wavelength of 200~800nm.

[0027] In this embodiment of the invention, the median particle size D of the transition metal oxide particles obtained after sand milling is... 50 The wavelength is 30~50nm.

[0028] Preferably, the mass ratio of transition metal oxide particles to chelating agent is (1 to 10):1. For example, the mass ratio of transition metal oxide particles to chelating agent is any one of 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any one of the ranges formed by any pairwise ratios mentioned above.

[0029] Preferably, the mass ratio of transition metal oxide particles to chelating agent is (5-7):1.

[0030] Preferably, the solid content of the suspension is 50% to 90%.

[0031] Preferably, the solid content of the suspension is 60% to 80%.

[0032] Preferably, the chelating agent solution has a mass percentage concentration of 1% to 20%.

[0033] Preferably, the high-speed stirring speed is 500–1000 r / min and the time is 20–60 min.

[0034] In a specific embodiment of the present invention, the equipment used for high-speed mixing can be a planetary mixer, a high-speed disperser, etc.

[0035] Thirdly, the present invention provides the application of the above-mentioned cathode material precursor in the preparation of cathode materials or secondary batteries.

[0036] Fourthly, the present invention provides a cathode material, wherein the raw materials for preparing the cathode material include the above-mentioned cathode material precursor, or the cathode material precursor obtained by the above-mentioned solid-phase preparation method.

[0037] Fifthly, the present invention provides a secondary battery comprising the aforementioned positive electrode material.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] This invention adds a chelating agent, which allows the carboxyl groups in the chelating agent to combine with the metal oxide nanoparticles, effectively agglomerating the metal oxide nanoparticles into clusters with high density, preventing them from becoming loose and brittle.

[0040] When the chelating agent of this invention has two or more carboxyl groups, it can bind with multiple metal oxides at the same time, which helps to achieve uniform distribution of elements in nanoparticles.

[0041] The solid-phase preparation method of the present invention, through an appropriate granulation process, enables the chelating agent to play an appropriate role, thereby obtaining metal oxide nanoparticles with the expected particle size;

[0042] The solid-phase preparation method of the present invention is added directly after the traditional solid-phase sand milling process, without significantly increasing the viscosity of the mixed slurry after sand milling, which is conducive to the smooth implementation of the subsequent drying process;

[0043] The solid-phase preparation method of this invention has simple process steps and is easy to operate. Attached Figure Description

[0044] Figure 1 This is an EDS layered image of secondary particles after treatment with a chelating agent.

[0045] Figure 2 This is an electronic image of Fe elements in secondary particles after treatment with a chelating agent.

[0046] Figure 3 This is an electronic image of Mn elements in secondary particles after treatment with a chelating agent.

[0047] Figure 4 This is an electronic image of Ni elements in secondary particles after treatment with a chelating agent.

[0048] Figure 5 This is an EDS layered image of secondary particles without chelating agent treatment.

[0049] Figure 6 This is an electronic image of Fe elements in secondary particles without chelating agent treatment.

[0050] Figure 7 This is an electronic image of Mn elements in secondary particles without chelating agent treatment.

[0051] Figure 8 This is an electronic image of the secondary Ni particles without chelating agent treatment. Detailed Implementation

[0052] This invention discloses a cathode material precursor and its preparation method. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0053] The reagents, instruments, and materials used in this invention can all be obtained through commercial channels.

[0054] The present invention will be further illustrated below with reference to the embodiments:

[0055] Example 1

[0056] I. Solid-phase preparation method of cathode material precursor

[0057] (1) The iron oxide particles were sand-milled to obtain D 50 Iron oxide particles approximately 30 nm in size.

[0058] (2) Take 350g of D 50 Iron oxide particles of approximately 30 nm are thoroughly mixed with water to form a suspension with a solid content of approximately 70%. This suspension is then fed into a high-speed disperser in one go.

[0059] (3) Dissolve 70g of chelating agent iminodiacetic acid (IDA) in 3kg of water to form a chelating agent solution.

[0060] (4) Add 50g of chelating agent solution into a high-speed disperser and mix at a speed of 500 rpm for 5 minutes.

[0061] (5) Repeat the previous step until 150g of chelating agent solution is added to the iron oxide suspension.

[0062] (6) The iron oxide suspension after mixing with chelating agent is mixed at a high speed of 500 rpm for 30 minutes in a high-speed disperser to obtain a nano iron oxide particle suspension.

[0063] (7) Separate the solid from the suspension of nano-iron oxide particles, spray dry it, and obtain nano-iron oxide particles in powder form (cathode material precursor).

[0064] II. Performance Testing of Cathode Material Precursor

[0065] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 22 cp and 86 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0066] The nano-iron oxide particle suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 470nm.

[0067] The morphology of the nano-iron oxide particles prepared in step (7) was tested by SEM, which showed that the iron oxide nanoparticles were mainly spherical.

[0068] Example 2

[0069] I. Solid-phase preparation method of cathode material precursor

[0070] (1) The iron oxide particles were sand-milled to obtain D 50 Iron oxide particles approximately 30 nm in size.

[0071] (2) Take 350g of D 50 Iron oxide particles of approximately 30 nm are thoroughly mixed with water to form a suspension with a solid content of approximately 70%. This suspension is then fed into a high-speed disperser in one go.

[0072] (3) Dissolve 50g of chelating agent phosphoroacetic acid (PAA) in 300g of water to form a chelating agent solution.

[0073] (4) Add 350g of the chelating agent solution into the high-speed disperser at once.

[0074] (5) The iron oxide suspension after mixing with chelating agent is mixed at a high speed of 1000 rpm for 30 minutes in a high-speed disperser to obtain a nano iron oxide particle suspension.

[0075] (6) Separate the solid from the suspension of nano-iron oxide particles, spray dry it, and obtain nano-iron oxide particles in powder form (cathode material precursor).

[0076] II. Performance Testing of Cathode Material Precursor

[0077] The suspensions from steps (2) and (5) were subjected to viscosity tests, which yielded 15 cp and 64 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial for the smooth implementation of the subsequent drying process.

[0078] The nano-iron oxide suspension prepared in step (5) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 260nm.

[0079] The morphology of the nano-iron oxide particles prepared in step (6) was tested by SEM, which showed that the iron oxide nanoparticles were mainly spherical.

[0080] Example 3

[0081] I. Solid-phase preparation method of cathode material precursor

[0082] (1) Iron oxide particles, manganese oxide particles, and nickel oxide particles were respectively ground to obtain D 50 Metal oxide particles approximately 50 nm in size.

[0083] (2) Mix 350g of iron oxide particles, manganese oxide particles, and nickel oxide particles in a molar ratio of 4:3:3 (where D) 50 (Approximately 50 nm) is added to a certain amount of water and mixed thoroughly to form a suspension with a solid content of approximately 70%. This suspension is then fed into a high-speed disperser in one go.

[0084] (3) Dissolve 70g of chelating agent nitrotriacetic acid (NTA) in 3kg of water to form a chelating agent solution.

[0085] (4) Put 50g of the chelating agent solution into a high-speed disperser and mix at a speed of 500 rpm for 5 minutes.

[0086] (5) Repeat the previous step until 150g of chelating agent solution is added to the suspension.

[0087] (6) The metal oxide suspension after mixing with chelating agent is mixed at a high speed of 500 rpm for 30 minutes in a high-speed disperser to obtain a nano metal oxide particle suspension.

[0088] (7) Separate the solid from the suspension of nano-metal oxide particles, spray dry it, and obtain nano-metal oxide particles in powder form (cathode material precursor).

[0089] II. Performance Testing of Cathode Material Precursor

[0090] The suspensions from steps (2) and (6) were subjected to viscosity tests, which yielded 34 cp and 101 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial for the smooth implementation of the subsequent drying process.

[0091] The nano-metal oxide suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 530nm.

[0092] The nano-metal oxide particles prepared in step (7) were analyzed using SEM, which showed that the nano-metal oxide particles were mainly spherical. EDS analysis of the elemental distribution uniformity within the particles showed that iron, manganese, and nickel were uniformly distributed, with no obvious segregation. Figures 1-4 ).

[0093] Example 4

[0094] I. Solid-phase preparation method of cathode material precursor

[0095] Similar to Example 1, the only difference is that the chelating agent used is ethylenediaminetetraacetic acid (EDTA).

[0096] II. Performance Testing of Cathode Material Precursor

[0097] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 27 cp and 92 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0098] The nano-iron oxide particle suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 550nm.

[0099] The morphology of the nano-iron oxide particles prepared in step (7) was tested by SEM, which showed that the iron oxide nanoparticles were mainly spherical.

[0100] Example 5

[0101] I. Solid-phase preparation method of cathode material precursor

[0102] Similar to Example 1, the only difference is that the chelating agent used is diethylenetriaminepentaacetic acid (DTPA).

[0103] II. Performance Testing of Cathode Material Precursor

[0104] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 27 cp and 110 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0105] The nano-iron oxide particle suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 620nm.

[0106] The morphology of the nano-iron oxide particles prepared in step (7) was tested by SEM, which showed that the iron oxide nanoparticles were mainly spherical.

[0107] Example 6

[0108] I. Solid-phase preparation method of cathode material precursor

[0109] Similar to Example 2, the only difference is that the chelating agents used are 3-phosphorylpropionic acid (CEPA) and 4-phosphorylbutyric acid (APPA), with a mass ratio of 1:1.

[0110] II. Performance Testing of Cathode Material Precursor

[0111] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 13 cp and 77 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0112] The nano-iron oxide suspension prepared in step (5) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 290nm.

[0113] The morphology of the nano-iron oxide particles prepared in step (6) was tested by SEM, which showed that the iron oxide nanoparticles were mainly spherical.

[0114] Example 7

[0115] I. Solid-phase preparation method of cathode material precursor

[0116] Similar to Example 3, the only difference is that the chelating agents used are 5-phosphatidylvaleric acid (APA) and p-carboxyphenylphosphonic acid (CPPA), with a mass ratio of 1:1.

[0117] II. Performance Testing of Cathode Material Precursor

[0118] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 31 cp and 89 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0119] The nano-metal oxide suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 340nm.

[0120] The nano-metal oxide particles prepared in step (7) were examined using SEM, which showed that the nano-metal oxide particles were mainly spherical. The uniformity of elemental distribution within the particles was tested using EDS, which showed that iron, manganese, and nickel were evenly distributed without obvious segregation.

[0121] Example 8

[0122] I. Solid-phase preparation method of cathode material precursor

[0123] Similar to Example 3, the only difference is that the metal oxide particles used are titanium dioxide (Ti2O3), vanadium trioxide (V2O3), and chromium trioxide (Cr2O3).

[0124] II. Performance Testing of Cathode Material Precursor

[0125] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 29 cp and 123 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0126] The nano-metal oxide suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 680nm.

[0127] The nano-metal oxide particles prepared in step (7) were examined using SEM, which showed that the nano-metal oxide particles were mainly spherical. The uniformity of elemental distribution within the particles was tested using EDS, which showed that titanium, vanadium, and chromium were uniformly distributed without obvious segregation.

[0128] Example 9

[0129] I. Solid-phase preparation method of cathode material precursor

[0130] Similar to Example 3, the only difference is that the metal oxide particles used are cobalt oxide (CoO), copper oxide (CuO), and zinc oxide (ZnO).

[0131] II. Performance Testing of Cathode Material Precursor

[0132] The suspensions from steps (2) and (6) were tested for viscosity, and the results were 28 cp and 131 cp, respectively. The addition of the chelating agent solution did not significantly increase the viscosity of the mixed slurry after sand milling, which is beneficial to the smooth progress of the subsequent drying process.

[0133] The nano-metal oxide suspension prepared in step (6) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 740nm.

[0134] The nano-metal oxide particles prepared in step (7) were examined using SEM, which showed that the nano-metal oxide particles were mainly spherical. The uniformity of elemental distribution within the particles was tested using EDS, which showed that cobalt, copper, and zinc were evenly distributed without obvious segregation.

[0135] Comparative Example 1

[0136] I. Solid-phase preparation method of cathode material precursor

[0137] Unlike Example 3, no chelating agent was added.

[0138] (1) Iron oxide particles, manganese oxide particles, and nickel oxide particles were respectively ground to obtain D 50 Metal oxide particles approximately 50 nm in size.

[0139] (2) Mix 350g of iron oxide particles, manganese oxide particles, and nickel oxide particles in a molar ratio of 4:3:3 (where D) 50 (Approximately 50 nm) is added to a certain amount of water and mixed thoroughly to form a suspension with a solid content of approximately 70%. This suspension is then fed into a high-speed disperser in one go.

[0140] (3) The suspension was mixed at a high speed of 500 rpm for 30 minutes in a high-speed disperser to obtain a metal oxide particle suspension.

[0141] (4) Separate the solid from the metal oxide particle suspension, spray dry it to obtain powdered metal oxide particles (cathode material precursor).

[0142] II. Performance Testing of Cathode Material Precursor

[0143] The metal oxide suspension prepared in step (3) was tested using a laser particle size analyzer, and the particle size D of the product was determined. 50 It is 240nm.

[0144] The metal oxide particles prepared in step (4) were examined using SEM. The results showed that only a small number of the particles were spherical, while a large number were plate-like. EDS analysis revealed uneven distribution of elements within the particles, indicating that iron, manganese, and nickel were not uniformly distributed. Figures 5-8 ).

[0145] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cathode material precursor, characterized in that, The cathode material precursor includes primary particles and secondary particles; the primary particles are complexes formed by transition metal oxide particles combining with carboxyl groups in a chelating agent, and the secondary particles are aggregates of at least two primary particles. The chelating agent is a chelating agent having at least two carboxyl groups.

2. The cathode material precursor according to claim 1, characterized in that, The median particle size D of the transition metal oxide particles 50 The median particle size D of the cathode material precursor is 20~60nm. 50 The range is 200~800nm.

3. The cathode material precursor according to claim 1, characterized in that, The chelating agent includes a first chelating agent, or a first chelating agent and a second chelating agent; The first chelating agent is an aminocarboxylic acid chelating agent; The second chelating agent is a chelating agent having the general formula shown in Formula I: Formula I Among them, R1 is selected from C 1-10 Alkyl or phenyl groups.

4. The cathode material precursor according to claim 3, characterized in that, The first chelating agent includes at least one of iminodiacetic acid (IDA), nitrotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA); The second chelating agent includes at least one of phosphorylacetic acid (PAA), 3-phosphorylated propionic acid (CEPA), 4-phosphorylated butyric acid (APPA), 5-phosphorylated valerate (APA), and p-carboxyphenylphosphonic acid (CPPA).

5. The cathode material precursor according to any one of claims 1-4, characterized in that, The transition metal oxides include at least one of the following: iron oxide, manganese oxide, nickel oxide, titanium oxide, vanadium oxide, chromium oxide, cobalt oxide, copper oxide, and zinc oxide.

6. A solid-phase preparation method of the cathode material precursor according to any one of claims 1-5, characterized in that, Includes the following steps: Transition metal oxide raw materials are milled to obtain a median particle size D. 50 The transition metal oxide particles are 20~60nm in size. The transition metal oxide particles are mixed with water to obtain a suspension. The chelating agent is mixed with water to obtain a chelating agent solution; The suspension was mixed with a chelating agent solution and stirred at high speed. The solid was then separated and dried to obtain the median particle size D. 50 It is a precursor for cathode materials with a wavelength of 200~800nm.

7. The solid-phase preparation method according to claim 6, characterized in that, The mass ratio of the transition metal oxide particles to the chelating agent is 1 to 10:1; The solid content of the suspension is 50% to 90%; The chelating agent solution has a mass percentage concentration of 1% to 20%.

8. The solid-phase preparation method according to claim 6 or 7, characterized in that, The high-speed stirring speed is 500-1000 r / min, and the time is 20-60 min.

9. A positive electrode material, characterized in that, The raw materials for preparing the cathode material include the cathode material precursor according to any one of claims 1-5, or the cathode material precursor prepared by any one of claims 6-8.

10. A secondary battery, characterized in that, The secondary battery includes the positive electrode material as described in claim 9.

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