Preparation method of electrode material
By mixing lithium iron phosphate precursors of different particle sizes, the microstructure of the electrode material was optimized, solving the problem of improving the energy density and electrical performance stability of lithium iron phosphate batteries, and realizing the preparation of electrode materials with high density and low energy consumption.
Patent Information
- Application Number
- CN202410634355.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies increase the compaction density of lithium iron phosphate electrode materials by raising the sintering temperature, which leads to a decline in electrical performance and makes it difficult to maintain stable electrical performance while increasing energy density.
A method for preparing lithium iron phosphate precursors with different particle sizes was adopted. By mixing a first precursor with a particle size D50 of 0.8-1.3 μm and a second precursor with a particle size D50 of 0.3-0.4 μm, the microstructure was optimized, a wider particle size distribution was achieved, and the compaction density of the electrode material was increased.
It improves the compaction density of electrode materials and the energy density of batteries, while also improving electrochemical performance and charge/discharge efficiency, and reducing sintering temperature and production energy consumption.
Smart Images
Figure CN120987286A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery materials, and specifically to a method for preparing an electrode material. Background Technology
[0002] In lithium-ion batteries, lithium iron phosphate (LiFePO4) has attracted much attention as a cathode material due to its excellent safety performance, low cost, stable chemical structure, and long cycle life. With increasing market demands for battery performance, especially the pursuit of higher energy density, improving the energy density of lithium iron phosphate batteries has become a pressing technical problem.
[0003] Currently, increasing the compaction density of lithium iron phosphate electrode materials is considered an effective way to increase battery energy density. Traditionally, increasing the sintering temperature promotes particle growth, thereby increasing the material's compaction density. However, this method leads to a decrease in electrical performance. Summary of the Invention
[0004] In view of this, this application provides a method for preparing an electrode material.
[0005] A method for preparing an electrode material, comprising the following steps:
[0006] The preparation of a first precursor, which is formed by sintering a first raw material with a particle size D50 between 0.8 and 1.3 μm, and the preparation of a second precursor, which is formed by sintering a second raw material with a particle size D50 between 0.3 and 0.4 μm.
[0007] The first precursor and the second precursor are mixed at a mass ratio of 1:1 to 3:7 to obtain a preliminary mixture.
[0008] The initial mixture is sintered to obtain the electrode material.
[0009] In some possible implementations, the first precursor includes a first lithium iron phosphate precursor, and the step "preparing the first precursor" includes:
[0010] The first raw material and the first solvent are mixed to obtain a first slurry. The first raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The first solvent includes water.
[0011] The first slurry is milled to make the particle size D50 of the first slurry 0.8-1.3μm.
[0012] The first slurry is sintered to obtain the first lithium iron phosphate precursor.
[0013] In some possible implementations, the step "milling the first slurry" includes:
[0014] The first slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6 to 1.0 mm, so that the particle size D50 of the first slurry is 1.5 to 3.0 μm.
[0015] The first slurry is finely ground with zirconium beads of 0.2-0.3 mm in diameter, so that the particle size D50 of the first slurry is 0.8-1.3 μm.
[0016] In some possible implementations, the step "sintering the first slurry" includes:
[0017] The first slurry is spray-dried to obtain the first sintering body.
[0018] Under an inert gas atmosphere, the first sintering body is heated to 500-800°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then pulverized and sieved to obtain the first lithium iron phosphate precursor.
[0019] In some possible implementations, the second precursor comprises a second lithium iron phosphate precursor, and the step "preparing the second precursor" includes:
[0020] A second raw material and a second solvent are mixed to obtain a second slurry. The second raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The second solvent includes water.
[0021] The second slurry is milled to achieve a particle size D50 of 0.3-0.4 μm.
[0022] The second slurry is sintered to obtain the second lithium iron phosphate precursor.
[0023] In some possible implementations, the step "milling the second slurry" includes:
[0024] The second slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6–1.0 mm, so that the particle size D50 of the second raw material is 1.5–3.0 μm.
[0025] The second slurry is finely ground, with the diameter of the milled zircon beads being 0.2-0.3 mm, so that the particle size D50 of the second raw material is 0.3-0.4 μm.
[0026] In some possible implementations, the step "sintering the second slurry" includes:
[0027] The second slurry is spray-dried to obtain the second sintering body.
[0028] Under an inert gas atmosphere, the second sintering body is heated to 300-700°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then pulverized and sieved to obtain the second lithium iron phosphate precursor.
[0029] In some possible embodiments, the molar ratio of the phosphorus source, the iron source, and the lithium source is (1.0-1.04):1:(1.015-1.036), and the additive includes at least one of titanium dioxide, tetrabutyl titanate, magnesium oxide, magnesium acetate, magnesium hydroxide, magnesium nitrate, zirconium nitrate, zirconium hydroxide, zirconium oxide, or niobium pentoxide.
[0030] In some possible implementations, the following steps are also included:
[0031] The primary mixture, carbon source, and water are mixed to obtain a secondary slurry, wherein the carbon source includes at least one of glucose, sucrose, starch, and polyethylene glycol.
[0032] The secondary slurry is milled to achieve a particle size D50 of 0.4–0.6 μm.
[0033] The secondary slurry is spray-dried to obtain the third sintering body.
[0034] In an inert gas atmosphere, the third sintering body is heated to 650-850°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then crushed, iron removed, and sieved to obtain the electrode material.
[0035] In some possible implementations, the step "sand milling the secondary slurry" includes:
[0036] The secondary slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6–1.0 mm, so that the particle size D50 of the secondary slurry is 1.0–2.0 μm.
[0037] The secondary slurry is subjected to fine grinding, with the diameter of the milled zircon beads being 0.2–0.3 mm, so that the particle size D50 of the secondary slurry is 0.4–0.6 μm.
[0038] In this application, mixing first and second precursors with different particle sizes can optimize the microstructure of the final electrode material, achieving a wider particle size distribution and facilitating particle size gradation. This effectively fills the voids between electrode materials, increasing the compaction density of the electrode material. Higher compaction density electrode materials help improve the energy density of the battery, enabling it to store more energy in the same volume. Attached Figure Description
[0039] Figure 1 This is a flowchart of an electrode material preparation method provided in an embodiment of this application.
[0040] Figure 2 SEM image of the large-particle lithium iron phosphate precursor prepared in Example 1.
[0041] Figure 3 SEM image of the small-particle lithium iron phosphate precursor prepared in Example 1.
[0042] Figure 4 This is a comparison diagram of the particle size distribution of the secondary mixed slurry in Example 1 and the secondary mixed slurry in the comparative example after sand milling.
[0043] Figure 5 The image shows a SEM image of the lithium iron phosphate electrode material prepared in Example 1.
[0044] Figure 6 SEM image of the lithium iron phosphate electrode material prepared for comparison. Detailed Implementation
[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0046] 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.
[0047] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0048] Please see Figure 1 , Figure 1 This is a schematic flowchart of one embodiment of the electrode material preparation method of this application, which includes the following steps S1-S4.
[0049] Step S1: Prepare a first precursor, which is sintered from a first raw material with a particle size D50 between 0.8 and 1.3 μm. Here, D50 refers to the particle size value that 50% of the particles in a particle group have a volume smaller than or equal to this value.
[0050] In this embodiment, the first precursor includes a first lithium iron phosphate precursor, and step S1 includes:
[0051] Step S11: Mix the first raw material with the first solvent to obtain a first slurry. The first raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The first solvent includes water. The molar ratio of the phosphorus source, the iron source, and the lithium source is (1.0-1.04):1:(1.015-1.036). The additives include at least one of titanium dioxide, tetrabutyl titanate, magnesium oxide, magnesium acetate, magnesium hydroxide, magnesium nitrate, zirconium nitrate, zirconium hydroxide, zirconium oxide, or niobium pentoxide. Controlling the proportions and mixing uniformity of the raw materials ensures the consistency of the chemical composition and the stability of the final product.
[0052] Step S12: Grind the first slurry to make the particle size D50 of the first slurry 0.8-1.3μm.
[0053] In this embodiment, step S12 includes:
[0054] Step S121: The first slurry is coarsely ground, and the diameter of the milled zirconium beads is 0.6 to 1.0 mm, so that the particle size D50 of the first slurry is 1.5 to 3.0 μm.
[0055] Step S122: The first slurry is finely ground, and the diameter of the milled zircon beads is 0.2-0.3 mm, so that the particle size D50 of the first slurry is 0.8-1.3 μm.
[0056] Step S13: Sinter the first slurry to obtain the first lithium iron phosphate precursor.
[0057] In this embodiment, step S13 includes:
[0058] Step S131: Spray dry the first slurry to obtain the first sintering body.
[0059] Step S132: Under an inert gas atmosphere, the first sintering body is heated to 500-800°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, pulverized and sieved to obtain the first lithium iron phosphate precursor. That is, high-temperature treatment promotes the solid-phase reaction of the raw material powder, forming the first lithium iron phosphate precursor with a crystalline structure.
[0060] Step S2: Prepare a second precursor, which is formed by sintering a second raw material with a particle size D50 between 0.3 and 0.4 μm.
[0061] In this embodiment, the second precursor includes a second lithium iron phosphate precursor. Similar to step S1, the difference is that step S2 prepares a second lithium iron phosphate precursor with a finer particle size. Smaller particle size is beneficial for improving the conductivity of the electrode material and the diffusion rate of lithium ions, thereby improving the charge-discharge performance of the battery. Step S2 includes:
[0062] Step S21: Mix the second raw material with the second solvent to obtain a second slurry. The second raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The second solvent includes water. The molar ratio of the phosphorus source, the iron source, and the lithium source is (1.0-1.04):1:(1.015-1.036). The additives include at least one of titanium dioxide, tetrabutyl titanate, magnesium oxide, magnesium acetate, magnesium hydroxide, magnesium nitrate, zirconium nitrate, zirconium hydroxide, zirconium oxide, or niobium pentoxide.
[0063] Step S22: Grind the second slurry to make the particle size D50 of the second slurry 0.3-0.4μm.
[0064] In this embodiment, step S22 includes:
[0065] Step S221: The second slurry is coarsely ground with zirconium beads of 0.6 to 1.0 mm in diameter, so that the particle size D50 of the second slurry is 1.5 to 3.0 μm.
[0066] Step S222: The second slurry is finely ground, and the diameter of the milled zircon beads is 0.2-0.3 mm, so that the particle size D50 of the second slurry is 0.3-0.4 μm.
[0067] Step S23: Sinter the second slurry to obtain the second lithium iron phosphate precursor.
[0068] In this embodiment, step S23 includes:
[0069] Step S231: Spray dry the second slurry to obtain the second sintering body.
[0070] Step S232: Under an inert gas atmosphere, the second body to be sintered is heated to 300-700°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, pulverized and sieved to obtain the second lithium iron phosphate precursor.
[0071] S3: Mix the first precursor and the second precursor at a mass ratio of 1:1 to 3:7 to obtain a preliminary mixture.
[0072] In this embodiment, step S3 further includes the following step:
[0073] Step S31: Mix the initial mixture, carbon source, and water to obtain a secondary slurry. The carbon source includes at least one of glucose, sucrose, starch, and polyethylene glycol. The introduction of the carbon source is to achieve carbon coating and improve the conductivity of the material.
[0074] Step S32: Grind the secondary slurry to make the particle size of the secondary slurry 0.4 to 0.6 μm.
[0075] In this embodiment, step S32 includes:
[0076] Step S321: The secondary slurry is coarsely ground with zirconium beads of 0.6-1.0 mm in diameter, so that the particle size D50 of the secondary slurry is 1.0-2.0 μm.
[0077] Step S322: The secondary slurry is finely ground, and the diameter of the milled zircon beads is 0.2-0.3 mm, so that the particle size D50 of the secondary slurry is 0.4-0.6 μm.
[0078] Step S4: Sinter the initial mixed slurry to obtain the electrode material.
[0079] In this embodiment, step S4 includes the following steps:
[0080] Step S41: Spray dry the secondary slurry to obtain the third sintering body.
[0081] Step S42: Under an inert gas atmosphere, the third body to be sintered is heated to 650-850°C at a rate of 2-5°C / min and held for 3-15 hours to obtain the electrode material.
[0082] In this embodiment, the preparation method of the electrode material further includes the step of: pulverizing, removing iron, and sieving the electrode material. This post-processing involves pulverizing, removing iron, and sieving the electrode material to obtain a product within a specific particle size range. This step helps improve the processing performance of the material and ensures its uniform coating and compaction during battery manufacturing.
[0083] The performance improvement brought about by the technical solution provided in this application is illustrated below with specific embodiments and comparative examples.
[0084] Example 1
[0085] (1) Mix 6 kg of glucose, 525.5 g of titanium dioxide, 25 kg of lithium carbonate, 100 kg of iron phosphate and 142 kg of water evenly, wherein the molar ratio of lithium:iron:phosphorus is 1.039:1:1.032, to obtain the first slurry.
[0086] (2) The first slurry was coarsely ground in a sand mill (zirconium bead diameter 0.6 mm), resulting in a particle size D50 of 1.93 μm after one sand milling. It was then finely ground in a sand mill (zirconium bead diameter 0.3 mm), resulting in a particle size D50 of 1.2 μm after sand milling. It was then spray-dried at an inlet air temperature of 220°C and an outlet air temperature of 90°C to obtain the first sintering body. The first sintering body was then sintered under an inert atmosphere, with the temperature increased to 700°C at a rate of 2.5°C / min, held at that temperature for 7.5 hours, and finally cooled to obtain a large-particle first lithium iron phosphate precursor. Please refer to [link to relevant documentation]. Figure 2 , Figure 2 The image shows a SEM image of the large-particle lithium iron phosphate precursor prepared in Example 1. Based on the scale bar, the approximate particle size can be estimated to be about 1 μm, indicating uniform particle size. Furthermore, the images show that the particles exhibit irregular shapes and are interconnected, forming a porous structure. This porous structure facilitates electrolyte penetration and may help improve lithium-ion diffusion efficiency.
[0087] (3) Preparation of the second lithium iron phosphate precursor is similar to that of the first lithium iron phosphate precursor, except that: after fine grinding, the particle size D50 of the second slurry is 0.37 μm. Under an inert atmosphere, the temperature is raised to 450℃ at a rate of 2.5℃ / min, held for 7.5 hours, and finally cooled to obtain small-particle second lithium iron phosphate precursor. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 The image shows a SEM image of the small-particle second lithium iron phosphate precursor prepared in Example 1. According to the scale bar, the size of the second lithium iron phosphate precursor is approximately 0.2 μm, significantly smaller than that of the first lithium iron phosphate precursor. Meanwhile, its appearance morphology is roughly similar to that of the first lithium iron phosphate precursor.
[0088] (4) The first lithium iron phosphate precursor and the second lithium iron phosphate precursor were mixed evenly at a mass ratio of 50:50 to obtain a primary mixture. 100 kg of the primary mixture, 3.3 kg of glucose, 6.0 kg of polyethylene glycol (molecular weight 6000), and 136 kg of water were mixed and stirred evenly to obtain a secondary slurry. The secondary slurry was coarsely ground in a sand mill (zirconium bead diameter 0.6 mm) until the particle size D50 = 1.68 μm. Then, it was finely ground in a sand mill (zirconium bead diameter 0.3 mm) until the particle size D50 = 0.5 μm. Particle size distribution analysis was performed on the finely ground secondary slurry; the results are shown in [reference needed]. Figure 4The material is then spray-dried at an inlet air temperature of 240°C and an outlet air temperature of 95°C to obtain the third sintering body. This third sintering body is then sintered under an inert atmosphere, with the temperature increased to 740°C at a rate of 2.5°C / min and held for 7.5 hours. Finally, it is cooled, and then subjected to airflow pulverization, sieving, and iron removal to obtain the lithium iron phosphate electrode material of Example 1. Please refer to... Figure 5 , Figure 5 The image shows a SEM image of the lithium iron phosphate electrode material prepared in Example 1. It can be seen that the particle size of the lithium iron phosphate electrode material is approximately 0.1–2 μm, compared to… Figure 2 and Figure 3 In contrast, lithium iron phosphate electrode materials have a wider particle size distribution, which is beneficial for achieving particle size distribution.
[0089] Example 2 differs from Example 1 in that the first lithium iron phosphate precursor and the second lithium iron phosphate precursor are mixed evenly at a mass ratio of 40:60 to obtain a preliminary mixture. The other steps are the same, and finally, the lithium iron phosphate electrode material of Example 2 is obtained.
[0090] Example 3 differs from Example 1 in that the first lithium iron phosphate precursor and the second lithium iron phosphate precursor are mixed evenly at a mass ratio of 30:70 to obtain a preliminary mixture. The other steps are the same, and finally, the lithium iron phosphate electrode material of Example 3 is obtained.
[0091] The comparative example differs from Example 1 in that the first lithium iron phosphate precursor and the second lithium iron phosphate precursor are mixed uniformly at a mass ratio of 0:100, meaning that only the smaller-particle-size second lithium iron phosphate precursor is used for subsequent processing. Other steps are the same, ultimately yielding the comparative lithium iron phosphate electrode material. The particle size distribution of the second lithium iron phosphate precursor after fine grinding is shown in [reference needed]. Figure 4 ,from Figure 4 As can be seen, Example 1 has two peaks (approximately 0.55 μm and 5.5 μm), while the comparative example has only one peak (approximately 0.55 μm). Figure 6 SEM images of the lithium iron phosphate electrode materials prepared for comparison were obtained from... Figure 6 It can be seen that the particle size of the lithium iron phosphate electrode material prepared in the comparative example is between 0.1 and 1 μm, and the particle size distribution is narrower than that of the lithium iron phosphate electrode material prepared in Example 1.
[0092] The carbon content, powder compaction, and resistivity of the cathode materials from Examples 1, 2, 3, and the comparative examples were measured, and coin cells were fabricated using the same method. Then, parameters characterizing electrical performance (0.1C specific capacity, initial efficiency, and 1.0C specific capacity) were measured using methods disclosed in the prior art. The test results are shown in Table 1.
[0093] Table 1:
[0094]
[0095] As shown in Table 1, with the increase of the mass ratio of small-particle lithium iron phosphate precursors (50:50 to 40:60 and 30:70), the powder compaction of the electrode material gradually decreased from 2.60 to 2.55 and 2.52, while the 1.0C coin cell capacity increased from 140.8 mAh / g to 141.5 and 142.6 mAh / g. This is because an excessive number of small-particle lithium iron phosphate precursors leads to poor particle size distribution. The gaps between large-particle lithium iron phosphate precursors are filled with small-particle lithium iron phosphate precursors, leaving no additional gaps for too many small-particle lithium iron phosphate precursors to enter, thus reducing powder compaction. However, a large number of lithium iron phosphate precursors can increase the migration speed of lithium ions in the electrode material, reduce the migration distance, and improve coin cell performance. Compared with the comparative example, the compaction density of the lithium iron phosphate electrode material prepared in the example is significantly improved.
[0096] Compared with existing technologies, the electrode preparation method provided in this application has the following advantages:
[0097] (i) Improving the structural uniformity of electrode materials: Mixing first and second lithium iron phosphate precursors with different particle sizes at a mass ratio of 1:1 to 3:7 can optimize the microstructure of the final lithium iron phosphate electrode material, achieving a wider particle size distribution. This structural uniformity is beneficial to improving the electrochemical performance of the electrode material, especially its stability and lifespan under high-rate charge-discharge conditions.
[0098] (II) Enhancing the compaction density of electrode materials: By designing a mixing ratio of large to small particles of 1:1 to 3:7, the voids between materials can be effectively filled, thereby increasing the compaction density of the electrode material. High compaction density lithium iron phosphate electrode materials help improve the energy density of the battery, enabling the battery to store higher energy within the same volume.
[0099] (III) Optimizing battery charge and discharge performance: Large-particle lithium iron phosphate precursors provide a stable framework structure, while small-particle lithium iron phosphate precursors fill the spaces between these frameworks, reducing the internal resistance of the electrode materials and simultaneously increasing the migration rate of lithium ions within the electrode materials. This structural optimization can significantly improve the battery's charge and discharge efficiency and cycle performance.
[0100] (iv) Reduce sintering temperature and reduce energy consumption: Mixing first lithium iron phosphate precursors and second lithium iron phosphate precursors with different particle sizes can achieve the preparation of high-quality electrode materials at a lower sintering temperature. This not only reduces energy consumption in the production process, but also reduces the preparation cost of electrode materials, while mitigating the environmental impact of the production process.
[0101] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.
Claims
1. A method for preparing an electrode material, characterized in that, Including the following steps: The preparation of a first precursor, wherein the first precursor is formed by sintering a first slurry with a particle size D50 between 0.8 and 1.3 μm, and the preparation of a second precursor, wherein the second precursor is formed by sintering a second slurry with a particle size D50 between 0.3 and 0.4 μm; The first precursor and the second precursor are mixed at a mass ratio of 1:1 to 3:7 to obtain a preliminary mixture. The initial mixture is sintered to obtain the electrode material.
2. The preparation method according to claim 1, characterized in that, The first precursor includes a first lithium iron phosphate precursor, and the step "preparing the first precursor" includes: The first raw material and the first solvent are mixed to obtain the first slurry. The first raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The first solvent includes water. The first slurry is milled to make the particle size D50 of the first slurry 0.8-1.3μm; The first slurry is sintered to obtain the first lithium iron phosphate precursor.
3. The preparation method according to claim 2, characterized in that, The step "milling the first slurry" includes: The first slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6–1.0 mm, so that the particle size D50 of the first slurry is 1.5–3.0 μm; The first slurry is finely ground with zirconium beads of 0.2-0.3 mm in diameter, so that the particle size D50 of the first slurry is 0.8-1.3 μm.
4. The preparation method according to claim 2, characterized in that, The step "sintering the first slurry" includes: The first slurry is spray-dried to obtain the first sintering body; Under an inert gas atmosphere, the first sintering body is heated to 500-800°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then pulverized and sieved to obtain the first lithium iron phosphate precursor.
5. The preparation method according to claim 1, characterized in that, The second precursor includes a second lithium iron phosphate precursor, and the step "preparing the second precursor" includes: The second raw material and the second solvent are mixed to obtain the second slurry. The second raw material includes a phosphorus source, an iron source, a lithium source, a carbon source, and additives. The second solvent includes water. The second slurry is milled to achieve a particle size D50 of 0.3-0.4 μm; The second slurry is sintered to obtain the second lithium iron phosphate precursor.
6. The preparation method according to claim 5, characterized in that, The step "sand milling the second slurry" includes: The second slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6–1.0 mm, so that the particle size D50 of the second slurry is 1.5–3.0 μm; The second slurry is finely ground with zirconium beads of 0.2-0.3 mm in diameter, so that the particle size D50 of the second slurry is 0.3-0.4 μm.
7. The preparation method according to claim 5, characterized in that, The step "sintering the second slurry" includes: The second slurry is spray-dried to obtain the second sintering body; Under an inert gas atmosphere, the second sintering body is heated to 300-700°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then pulverized and sieved to obtain the second lithium iron phosphate precursor.
8. The preparation method according to any one of claims 2-7, characterized in that, The molar ratio of the phosphorus source, the iron source, and the lithium source is (1.0-1.04):1:(1.015-1.036), and the additives include at least one of titanium dioxide, tetrabutyl titanate, magnesium oxide, magnesium acetate, magnesium hydroxide, magnesium nitrate, zirconium nitrate, zirconium hydroxide, zirconium oxide, or niobium pentoxide.
9. The preparation method according to claim 1, characterized in that, It also includes the following steps: The primary mixture, carbon source, and water are mixed to obtain a secondary slurry, wherein the carbon source includes at least one of glucose, sucrose, starch, and polyethylene glycol. The secondary slurry is milled to achieve a particle size D50 of 0.4–0.6 μm. The secondary slurry is spray-dried to obtain the third body to be sintered. In an inert gas atmosphere, the third sintering body is heated to 650-850°C at a rate of 2-5°C / min, held at that temperature for 3-15 hours, and then crushed, iron removed, and sieved to obtain the electrode material.
10. The preparation method according to claim 9, characterized in that, The step "sand milling the secondary slurry" includes: The secondary slurry is subjected to coarse grinding, with the diameter of the milled zircon beads being 0.6–1.0 mm, so that the particle size D50 of the secondary slurry is 1.0–2.0 μm; The secondary slurry is subjected to fine grinding, with the diameter of the milled zircon beads being 0.2–0.3 mm, so that the particle size D50 of the secondary slurry is 0.4–0.6 μm.