A ternary cathode material precursor, its preparation method and application

Abstract

This invention provides a ternary cathode material precursor, its preparation method, and its application. The preparation method includes: (1) wet milling a metal salt, a binder, a defoamer, and a solvent to obtain a slurry; (2) spray granulating the slurry under a pure oxygen atmosphere to obtain the ternary cathode material precursor. This invention uses solid-phase spray granulation technology to replace the traditional co-precipitation process for preparing ternary cathode material precursors, resulting in high production efficiency, short cycle time, no need for the addition of complexing agents with irritating odors, and simple process and equipment, making it highly feasible for industrialization.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and relates to a ternary cathode material precursor, its preparation method, and its application. Background Technology

[0002] Ternary cathode materials typically employ a co-precipitation process to prepare precursors, which are then blended with lithium salts and sintered at high temperatures. However, the co-precipitation method for precursor preparation is time-consuming, usually taking 3-7 days or even longer, resulting in relatively low production efficiency. Furthermore, the co-precipitation process is relatively lengthy, requiring significant investment in equipment and facilities. In addition, the solubility product constants of various metal elements (such as nickel, cobalt, and manganese) differ considerably during co-precipitation, leading to varying precipitation rates. Industrially, ammonia is commonly used as a complexing agent to regulate the precipitation rate and ensure product uniformity. However, ammonia has a pungent odor, resulting in a poor production environment and potential harm to workers.

[0003] Therefore, there is an urgent need to provide a preparation process for ternary cathode material precursors that can solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a ternary cathode material precursor, its preparation method, and its applications. This invention employs solid-phase spray granulation technology to replace the traditional co-precipitation process for preparing ternary cathode material precursors, resulting in high production efficiency, short cycle time, no need for the addition of odorous complexing agents, and simple process and equipment, making it highly feasible for industrialization.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a ternary cathode material precursor, the method comprising:

[0007] (1) The metal salt, binder, defoamer and solvent are wet-milled to obtain a slurry;

[0008] (2) The slurry is spray-granulated under a pure oxygen atmosphere to obtain the ternary cathode material precursor.

[0009] This invention provides a method for preparing a ternary cathode material precursor, employing solid-phase spray granulation technology to replace the traditional co-precipitation process. This method offers high production efficiency, a short cycle time, eliminates the need for odorous complexing agents, and simplifies the process and equipment, making it highly feasible for industrialization. The raw materials for this invention, in addition to metal salts and solvents, include binders and defoamers. The binder facilitates inter-particle adhesion during primary processing, while the defoamer eliminates bubbles generated during spray granulation. Furthermore, the spray granulation process is conducted under a pure oxygen atmosphere, enabling pre-oxidation that increases the overall valence state of the metal elements in the ternary cathode material precursor and removes OH groups. - (Volatilization in the form of water vapor) is beneficial for improving the compactness of the ternary cathode material precursor, thereby increasing its tap density and loose packing density. This, in turn, allows for a larger packing size in subsequent sintering, increasing production capacity. The corresponding compaction density of the ternary cathode material also increases, resulting in tighter particle contact and smaller internal micropores, effectively improving the volumetric energy density of the cathode. Furthermore, pre-oxidation ensures that the ternary cathode material precursor exists entirely in oxide form, exhibiting good uniformity and increasing its crystallinity. This is beneficial for improving the discharge capacity of the corresponding cathode material and enhancing its initial efficiency.

[0010] Preferably, the metal salt includes at least three of the following: divalent nickel salt, divalent cobalt salt, divalent manganese salt, and trivalent aluminum salt.

[0011] In this invention, the metal salt can be a combination of divalent nickel salt, divalent cobalt salt and divalent manganese salt, and the corresponding precursor is a nickel-cobalt-manganese ternary precursor; or it can be a combination of divalent nickel salt, divalent cobalt salt and trivalent aluminum salt, and the corresponding precursor is a nickel-cobalt-aluminum ternary precursor.

[0012] In this invention, the metal salt is preferably a combination of divalent nickel salt, divalent cobalt salt, and divalent manganese salt. The divalent nickel salt includes Ni. 2+ Divalent cobalt salts include Co 2+ Divalent manganese salts include Mn 2+ The three elements Ni, Co and Mn in the metal salt are transition metal elements and all have a +2 valence. After wet milling and spray granulation, the combined valence of Ni, Co and Mn in the ternary cathode material precursor increases to +3.

[0013] Preferably, the anion of the metal salt includes at least one selected from carbonate, oxalate, acetate, nitrate, and sulfate.

[0014] Optionally, the metal salt is a hydrated metal salt, meaning it contains bound water.

[0015] Preferably, the binder comprises at least one of hydroxypropyl cellulose, methylcellulose, hydroxypropyl methylcellulose, ethylcellulose, povidone, copovidone, and polyvinyl alcohol.

[0016] Preferably, the mass fraction of the binder is 0.5% to 2.5% based on the mass of the metal salt, for example, it can be 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, or 2.5%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, the defoamer includes at least one of polyether-modified silicone oil, polyurethane, organosilicon, alcohol, fatty acid, fatty acid ester, phosphate ester, mineral oil, and amide.

[0018] Preferably, the defoamer contains organosilicones, including polysiloxanes.

[0019] Preferably, the mass fraction of the defoamer is 0.1‰ to 3‰, based on the mass of the metal salt. For example, it can be 0.1‰, 0.2‰, 0.5‰, 0.8‰, 1‰, 1.5‰, 1.8‰, 2‰, 2.5‰, 2.8‰, or 3‰, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the raw material for wet milling further includes a lubricant, which includes at least one of silicone oil, glycerin, fatty acid amide, oleic acid, polyester, synthetic ester and carboxylic acid.

[0021] In this invention, the lubricant can improve the fluidity of the slurry, which helps the spherical particles formed by spray granulation to be more rounded, smooth, and have better sphericity.

[0022] Preferably, the mass fraction of the lubricant is 0.1‰ to 5‰, based on the mass of the metal salt. For example, it can be 0.1‰, 0.2‰, 0.5‰, 0.8‰, 1‰, 1.5‰, 1.8‰, 2‰, 2.5‰, 2.8‰, 3‰, 3.5‰, 4‰, 4.5‰, 4.8‰, or 5‰, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] In this invention, if the mass fraction of lubricant is too small, the improvement on slurry fluidity is not obvious, the sphericity of spray-granulated particles is poor, the surface of secondary spheres is uneven, the finished cathode material inherits the morphology of the precursor, resulting in an increase in the specific surface area of ​​the material and an increase in battery side reactions; if the mass fraction of lubricant is too large, it can lead to an increase in the internal resistance of the material, an increase in the proportion of inertness in the cathode material, and a decrease in electrochemical performance such as specific capacity.

[0024] Preferably, the raw material for wet milling further includes a dopant, which includes metal oxides and / or ammonium salts.

[0025] In this invention, introducing a dopant for bulk doping during the precursor preparation stage can ensure the uniformity of doping, achieve the ordered arrangement of dopant elements in the transition metal layer within the crystal lattice, and help form a homogeneous solid solution.

[0026] Preferably, the metal oxide includes at least one of ZrO2, Al2O3, TiO2, MgO, and WO3.

[0027] In this invention, the addition of metal oxides can dope the precursor with metal elements, including at least one of Zr, Al, Ti, Mg and W.

[0028] Preferably, based on the theoretical mass of the ternary cathode material precursor as 100%, the mass content of the metal element in the dopant is 500-8000 ppm.

[0029] Preferably, the ammonium salt comprises NH4F and / or NH4H2PO4.

[0030] In this invention, the addition of ammonium salts allows for non-metallic element doping of the precursor. When NH4F is added, the dopant ion is NH4. + and F - When doped with NH4H2PO4, the dopant ion is NH4. + and PO4 3- .

[0031] Preferably, the solvent includes water.

[0032] Preferably, the solid content in the mixture of metal salt, binder, defoamer, lubricant, dopant and solvent is 10% to 25%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22% or 25%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] Preferably, the wet milling method includes ball milling and / or sand milling.

[0034] Preferably, the particle size D50 of the slurry is 0.5μm to 2.5μm, for example, it can be 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm or 2.5μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] It should be noted that the particles in the slurry are wet-milled raw material particles that did not dissolve in the solvent after wet milling. No chemical reaction occurs during the wet milling process; only physical dispersion and mixing take place.

[0036] In this invention, when the particle size D50 of the slurry is between 0.5 μm and 2.5 μm, it is suitable for subsequent spray granulation. If the particle size D50 of the slurry is too small, it means that the wet grinding cycle is long, the efficiency is low, and the effect on improving product performance is small; if the particle size D50 of the slurry is too large, it will lead to uneven material dispersion, with local large particles causing some elements to be concentrated, and at the same time, it will result in larger primary particles on the surface of the secondary spheres after spraying, which is not conducive to the subsequent full mixing and wetting with lithium salt.

[0037] Preferably, the inlet air temperature of the spray granulation is 450℃~650℃, for example, it can be 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃ or 650℃, etc., and the outlet air temperature is 100℃~150℃, for example, it can be 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, etc., but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0038] In this invention, when the inlet air temperature for spray granulation is between 450℃ and 650℃, sufficient pre-oxidation can be carried out under a pure oxygen atmosphere, resulting in better uniformity and increased density of the precursor. Simultaneously, solvents (such as water) can be removed within this temperature range, and when the metal salt contains bound water, this bound water can be removed, making the ternary cathode material precursor more dense. If the inlet air temperature for spray granulation is too low, the pre-oxidation reaction of the precursor will be insufficient, and moisture removal will be incomplete; if the inlet air temperature for spray granulation is too high, oxygen corrosion of the equipment will be significant, affecting the equipment's service life.

[0039] Preferably, the spray granulation is carried out using a spray dryer.

[0040] Preferably, the chemical formula of the ternary cathode material precursor is (Ni x Co y Y zThe expression is: 2O3, where 0 < x < 1, 0 ≤ y < 1, 0 < z < 1, x + y + z = 1, and Y includes Mn and / or Al. The x value can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9; the y value can be, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9; and the z value can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0041] As a preferred technical solution of the present invention, the preparation method specifically includes:

[0042] (I) The metal salt, binder, defoamer, lubricant, dopant and solvent are wet-milled to obtain a slurry;

[0043] The metal salt comprises at least three of the following: divalent nickel salt, divalent cobalt salt, divalent manganese salt, and trivalent aluminum salt; the binder comprises at least one of the following: hydroxypropyl cellulose, methylcellulose, hydroxypropyl methylcellulose, ethylcellulose, povidone, copovidone, and polyvinyl alcohol; the defoamer comprises at least one of the following: polyether-modified silicone oil, polyurethane, organosilicon, alcohol, fatty acid, fatty acid ester, phosphate ester, mineral oil, and amide; the lubricant comprises at least one of the following: silicone oil, glycerin, fatty acid amide, oleic acid, polyester, synthetic ester, and carboxylic acid; the solvent comprises water; and the particle size D50 of the slurry is 0.5 μm to 2.5 μm.

[0044] (II) The slurry is stirred at a rate of 150 r / min to 500 r / min (e.g., 150 r / min, 180 r / min, 200 r / min, 300 r / min, 400 r / min or 500 r / min, etc.), and spray granulation is performed on the slurry as raw material under a pure oxygen atmosphere to obtain the ternary cathode material precursor;

[0045] The inlet air temperature for the spray granulation is 450℃~650℃, and the outlet air temperature is 100℃~150℃; the chemical formula of the ternary cathode material precursor is (Ni x Co y Y z )2O3, where 0 < x < 1, 0 ≤ y < 1, 0 < z < 1, x + y + z = 1, and Y includes Mn and / or Al.

[0046] In this invention, the slurry is stirred at a rate of 150 r / min to 500 r / min in order to prevent slurry segregation.

[0047] In a second aspect, the present invention provides a ternary cathode material precursor, which is prepared by the preparation method described in the first aspect.

[0048] Preferably, the particle size D50 of the ternary cathode material precursor is 5μm to 15μm, for example, it can be 5μm, 6μm, 7μm, 10μm, 12μm, 14μm or 15μm, etc.

[0049] Thirdly, the present invention provides a ternary cathode material, which is obtained by mixing and sintering the ternary cathode material precursor described in the second aspect with a lithium source.

[0050] Preferably, the lithium source includes at least one of lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate, and lithium acetate.

[0051] Preferably, the molar ratio of lithium element in the lithium source to transition metal element in the ternary cathode material precursor is 1.00 to 1.08, for example, it can be 1.00, 1.02, 1.05, 1.06 or 1.08, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] Preferably, the sintering temperature is 800℃~950℃, for example, it can be 800℃, 820℃, 850℃, 880℃, 900℃, 920℃ or 950℃, etc., and the sintering holding time is 10h~24h, for example, it can be 10h, 12h, 15h, 18h, 20h, 22h or 24h, etc., but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] Preferably, when the lithium source is lithium hydroxide, the sintering atmosphere is a pure oxygen atmosphere or an atmosphere with an oxygen volume content ≥90%; when the lithium source is lithium carbonate, lithium nitrate, lithium oxalate or lithium acetate, the sintering atmosphere is dry compressed air with a dew point ≤-40℃.

[0054] Preferably, after sintering, the sintered product is subjected to jaw crusher, roller crusher, pulverizer and 200-350 mesh sieve to obtain the ternary cathode material.

[0055] Preferably, the pulverization includes mechanical pulverization and / or air jet pulverization.

[0056] Fourthly, the present invention provides a lithium-ion battery, wherein the positive electrode of the lithium-ion battery includes the ternary positive electrode material described in the second aspect.

[0057] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] This invention provides a method for preparing a ternary cathode material precursor, employing solid-phase spray granulation technology to replace the traditional co-precipitation process. This method offers high production efficiency, a short cycle time, eliminates the need for odorous complexing agents, and simplifies the process and equipment, making it highly feasible for industrialization. The raw materials for this invention, in addition to metal salts and solvents, include binders and defoamers. The binder facilitates inter-particle adhesion during primary processing, while the defoamer eliminates bubbles generated during spray granulation. Furthermore, the spray granulation process is conducted under a pure oxygen atmosphere, enabling pre-oxidation that increases the overall valence state of the metal elements in the ternary cathode material precursor and removes OH groups. - (Volatilization in the form of water vapor) is beneficial for improving the compactness of the ternary cathode material precursor, thereby increasing its tap density and loose packing density. This, in turn, allows for a larger packing size in subsequent sintering, increasing production capacity. The corresponding compaction density of the ternary cathode material also increases, resulting in tighter particle contact and smaller internal micropores, effectively improving the volumetric energy density of the cathode. Furthermore, pre-oxidation ensures that the ternary cathode material precursor exists entirely in oxide form, exhibiting good uniformity and increasing its crystallinity. This is beneficial for improving the discharge capacity of the corresponding cathode material and enhancing its initial efficiency. Detailed Implementation

[0060] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0061] Example 1

[0062] This embodiment provides a method for preparing a ternary cathode material precursor, the method comprising:

[0063] (1) A slurry is obtained by wet milling a metal salt, binder, defoamer, lubricant, dopant, and solvent. The metal salt is a mixture of NiSO4·6H2O, CoSO4·7H2O, and MnSO4·H2O. The binder is polyvinyl alcohol, the defoamer is polyether-modified silicone oil, the lubricant is silicone oil, the dopant is ZrO2, and the solvent is deionized water. Based on the mass of the metal salt, the mass fraction of the binder is 1%, the mass fraction of the defoamer is 1‰, the mass fraction of the lubricant is 2‰, and the mass fraction of the dopant is 0.2%. The solid content of the mixture of the metal salt, binder, defoamer, lubricant, dopant, and solvent is 18%. The particle size D50 of the slurry is 1 μm.

[0064] (2) The slurry is discharged, and stirred with an electric stirrer at a rate of 400 r / min. The slurry is then introduced into a spray dryer for spray granulation under a pure oxygen atmosphere. The inlet air temperature for spray granulation is 450°C, and the outlet air temperature is 110°C, to obtain the ternary cathode material precursor. The chemical formula of the ternary cathode material precursor is (Ni... 0.83 Co 0.12 Mn 0.05 )2O3, with a particle size D50 of 15μm.

[0065] This embodiment also provides a method for preparing ternary cathode materials using the above-mentioned ternary cathode material precursor, the method comprising:

[0066] The ternary cathode material precursor and lithium carbonate are mixed, with the molar ratio of lithium element in lithium carbonate to transition metal element in ternary cathode material precursor being 1.04. Then, under a dry compressed air atmosphere, the mixture is sintered at 910℃ for 20 hours. After sintering, the temperature is allowed to drop below 100℃ before the furnace is opened, the material is collected, and then subjected to jaw crusher, roller crusher, mechanical crushing, and 200-mesh sieve to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0067] Example 2

[0068] This embodiment provides a method for preparing a ternary cathode material precursor, the method comprising:

[0069] (1) A slurry is obtained by wet milling a metal salt, binder, defoamer, lubricant, dopant, and solvent. The metal salt is a mixture of Ni(NO3)2·6H2O, Co(NO3)2·7H2O, and Mn(NO3)2·H2O. The binder is polyvinyl alcohol, the defoamer is polyether-modified silicone oil, the lubricant is silicone oil, the dopant is ZrO2, and the solvent is deionized water. Based on the mass of the metal salt, the mass fraction of the binder is 2.5%, the mass fraction of the defoamer is 2‰, the mass fraction of the lubricant is 3‰, and the mass fraction of the dopant is 0.3%. The solid content of the mixture of the metal salt, binder, defoamer, lubricant, dopant, and solvent is 21%. The particle size D50 of the slurry is 0.6 μm.

[0070] (2) The slurry is discharged, and stirred with an electric stirrer at a rate of 500 r / min. The slurry is then introduced into a spray dryer for spray granulation under a pure oxygen atmosphere. The inlet air temperature for spray granulation is 600℃, and the outlet air temperature is 120℃, to obtain the ternary cathode material precursor. The chemical formula of the ternary cathode material precursor is (Ni... 0.6 Co 0.2 Mn 0.2 )2O3, with a particle size D50 of 10μm.

[0071] This embodiment also provides a method for preparing ternary cathode materials using the above-mentioned ternary cathode material precursor, the method comprising:

[0072] The ternary cathode material precursor and lithium carbonate are mixed, with the molar ratio of lithium element in lithium carbonate to transition metal element in ternary cathode material precursor being 1.06. Then, the mixture is sintered at 880℃ for 24 hours in a dry compressed air atmosphere. After sintering, the furnace is opened after the temperature drops below 100℃, the material is collected, and then subjected to jaw crusher, roller crusher, mechanical crushing and 200-mesh sieve to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0073] Example 3

[0074] The difference between this embodiment and Embodiment 1 is that the mass fraction of the lubricant in step (1) is adjusted to 0.05‰.

[0075] The remaining parameters are the same as in Example 1.

[0076] Example 4

[0077] The difference between this embodiment and Embodiment 1 is that the mass fraction of the lubricant in step (1) is adjusted to 5.2‰.

[0078] The remaining parameters are the same as in Example 1.

[0079] Example 5

[0080] The difference between this embodiment and embodiment 1 is that in step (1), the particle size D50 of the slurry is 0.3 μm.

[0081] The remaining parameters are the same as in Example 1.

[0082] Example 6

[0083] The difference between this embodiment and embodiment 1 is that in step (1), the particle size D50 of the slurry is 2.8 μm.

[0084] The remaining parameters are the same as in Example 1.

[0085] Example 7

[0086] The difference between this embodiment and embodiment 1 is that the air inlet temperature for spray granulation in step (2) is adjusted to 420°C.

[0087] The remaining parameters are the same as in Example 1.

[0088] Example 8

[0089] The difference between this embodiment and embodiment 1 is that the air inlet temperature for spray granulation in step (2) is adjusted to 680°C.

[0090] The remaining parameters are the same as in Example 1.

[0091] Example 9

[0092] This embodiment provides a method for preparing a ternary cathode material precursor, the method comprising:

[0093] (1) A slurry is obtained by wet milling a metal salt, binder, defoamer, lubricant, dopant, and solvent. The metal salt is a mixture of Ni(NO3)2·6H2O, Co(NO3)2·7H2O, and Al(NO3)3·9H2O. The binder is polyvinyl alcohol, the defoamer is polyether-modified silicone oil, the lubricant is silicone oil, the dopant is ZrO2, and the solvent is deionized water. Based on the mass of the metal salt, the mass fraction of the binder is 2.5%, the mass fraction of the defoamer is 2‰, the mass fraction of the lubricant is 3‰, and the mass fraction of the dopant is 0.3%. The solid content of the mixture of the metal salt, binder, defoamer, lubricant, dopant, and solvent is 21%. The particle size D50 of the slurry is 0.6 μm.

[0094] (2) The slurry is discharged, and stirred with an electric stirrer at a rate of 500 r / min. The slurry is then introduced into a spray dryer for spray granulation under a pure oxygen atmosphere. The inlet air temperature for spray granulation is 600℃, and the outlet air temperature is 120℃, to obtain the ternary cathode material precursor. The chemical formula of the ternary cathode material precursor is (Ni... 0.8 Co 0.15 Al 0.05 )2O3, with a particle size D50 of 10μm.

[0095] This embodiment also provides a method for preparing ternary cathode materials using the above-mentioned ternary cathode material precursor, the method comprising:

[0096] The ternary cathode material precursor and lithium carbonate are mixed, with the molar ratio of lithium element in lithium carbonate to transition metal element in ternary cathode material precursor being 1.06. Then, the mixture is sintered at 880℃ for 24 hours in a dry compressed air atmosphere. After sintering, the furnace is opened after the temperature drops below 100℃, the material is collected, and then subjected to jaw crusher, roller crusher, mechanical crushing and 200-mesh sieve to obtain lithium nickel cobalt aluminum oxide ternary cathode material.

[0097] Comparative Example 1

[0098] The difference between this comparative example and Example 1 is that the atmosphere for spray granulation is adjusted to an air atmosphere.

[0099] The remaining parameters are the same as in Example 1.

[0100] Performance testing

[0101] The tap density and loose pack density of the ternary cathode material precursors provided in the above embodiments and comparative examples were tested; the first-efficiency test of the provided ternary cathode material was also performed.

[0102] Tap density: Refer to GB / T 31057.2 Physical properties test of particulate materials, Part 2: Measurement of tap density.

[0103] Loose packing density: Refer to GB / T 31057.1 Physical properties test of particulate materials - Part 1: Measurement of loose packing density.

[0104] First-time performance: Refer to GB / T 23365-2023 Test method for first-time discharge specific capacity and first-time charge-discharge efficiency of lithium cobalt oxide electrochemical performance test.

[0105] The test results are shown in Table 1.

[0106] Table 1

[0107] <![CDATA[Tap density (g / cm 3 )]]> <![CDATA[Apparent density (g / cm 3 )]]> First-efficacy (%) Example 1 2.31 1.18 88 Example 2 2.29 1.15 87 Example 3 2.28 1.13 85 Example 4 2.24 1.10 81 Example 5 2.26 1.09 84 Example 6 2.29 1.14 81 Example 7 2.29 1.15 82 Example 8 2.31 1.18 84 Example 9 2.28 1.14 88 Comparative Example 1 2.26 1.12 80

[0108] analyze:

[0109] As can be seen from Examples 1-2 and Example 9, the ternary precursor material prepared by the method of the present invention is dense with small particle gaps, and has a high loading capacity in subsequent sintering, which can improve production capacity and production efficiency; the corresponding ternary cathode material has a high initial efficiency.

[0110] As can be seen from Examples 1 and 3-4, if the mass fraction of lubricant in the wet-milled raw material is too small, the precursor material particles will have a rough surface, a large specific surface area, and a reduced density; if the mass fraction of lubricant is too large, the particle size will be small, the tap density will be reduced, and the first-time efficiency of the cathode material will decrease.

[0111] As can be seen from Examples 1 and 5-6, after wet milling, if the particle size D50 in the slurry is too small, the secondary ball particles will be smaller, resulting in lower compaction and loose packing density; if the particle size D50 in the slurry is too large, the primary particles on the surface of the secondary ball particles will be larger, the gaps between the primary particles will be larger, the specific surface area will increase, and the electrochemical performance of the material will decrease (initial efficiency decreases).

[0112] As can be seen from Examples 1 and 7-8, if the inlet air temperature of spray granulation is too low, the precursor pre-oxidation will be insufficient, the material uniformity will be poor, and the overall performance will be reduced. If the inlet air temperature of spray granulation is too high, the precursor will be over-oxidized, resulting in larger primary particles on the surface of the secondary spheres, reduced first-stage efficiency, and significant oxygen corrosion to the spraying equipment.

[0113] As can be seen from Example 1 and Comparative Example 1, when the atmosphere of spray granulation is adjusted to an air atmosphere, the precursor pre-oxidation is insufficient, the material uniformity is poor, and the overall performance decreases.

[0114] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a ternary cathode material precursor, characterized in that, The preparation method includes: (1) The metal salt, binder, defoamer and solvent are wet-milled to obtain a slurry; (2) The slurry is spray-granulated under a pure oxygen atmosphere to obtain the ternary cathode material precursor; The inlet air temperature of the spray granulation is 450℃~650℃, and the outlet air temperature is 100℃~150℃. The chemical formula of the ternary cathode material precursor is (Ni x Co y Y z )2O3, where 0 < x < 1, 0 ≤ y < 1, 0 < z < 1, x + y + z = 1, and Y includes Mn and / or Al.

2. The preparation method according to claim 1, characterized in that, The metal salt includes at least three of the following: divalent nickel salt, divalent cobalt salt, divalent manganese salt, and trivalent aluminum salt.

3. The preparation method according to claim 1, characterized in that, The binder includes at least one of hydroxypropyl cellulose, methylcellulose, hydroxypropyl methylcellulose, ethylcellulose, povidone, copovidone, and polyvinyl alcohol.

4. The preparation method according to claim 1, characterized in that, Based on the mass of the metal salt, the mass fraction of the binder is 0.5% to 2.5%.

5. The preparation method according to claim 1, characterized in that, The defoamer includes at least one of polyether-modified silicone oil, polyurethane, organosilicon, alcohol, fatty acid, fatty acid ester, phosphate ester, mineral oil, and amide.

6. The preparation method according to claim 1, characterized in that, Based on the mass of the metal salt, the mass fraction of the defoamer is 0.1‰ to 3‰.

7. The preparation method according to claim 1, characterized in that, The raw materials for wet milling also include lubricants, which include at least one of silicone oil, glycerin, fatty acid amide, oleic acid, polyester, synthetic ester and carboxylic acid.

8. The preparation method according to claim 7, characterized in that, Based on the mass of the metal salt, the mass fraction of the lubricant is 0.1‰ to 5‰.

9. The preparation method according to claim 1, characterized in that, The raw materials for wet milling also include dopants, which include metal oxides and / or ammonium salts.

10. The preparation method according to claim 9, characterized in that, The metal oxide includes at least one of ZrO2, Al2O3, TiO2, MgO, and WO3.

11. The preparation method according to claim 9, characterized in that, The ammonium salt includes NH4F and / or NH4H2PO4.

12. The preparation method according to claim 1, characterized in that, The solvent includes water.

13. The preparation method according to claim 1, characterized in that, The mixture of metal salt, binder, defoamer, lubricant, dopant and solvent has a solid content of 10% to 25%.

14. The preparation method according to claim 1, characterized in that, The wet milling methods include ball milling and / or sand milling.

15. The preparation method according to claim 1, characterized in that, The particle size D50 of the slurry is 0.5μm~2.5μm.

16. The preparation method according to claim 1, characterized in that, The preparation method specifically includes: (I) The metal salt, binder, defoamer, lubricant, dopant and solvent are wet-milled to obtain a slurry; The metal salt comprises at least three of the following: divalent nickel salt, divalent cobalt salt, divalent manganese salt, and trivalent aluminum salt; the binder comprises at least one of the following: hydroxypropyl cellulose, methylcellulose, hydroxypropyl methylcellulose, ethylcellulose, povidone, copovidone, and polyvinyl alcohol; the defoamer comprises at least one of the following: polyether-modified silicone oil, polyurethane, organosilicon, alcohol, fatty acid, fatty acid ester, phosphate ester, mineral oil, and amide; the lubricant comprises at least one of the following: silicone oil, glycerin, fatty acid amide, oleic acid, polyester, synthetic ester, and carboxylic acid; the solvent comprises water; and the particle size D50 of the slurry is 0.5 μm to 2.5 μm. (II) The slurry is stirred at a rate of 150 r / min to 500 r / min, and spray granulation is performed on the slurry as raw material under a pure oxygen atmosphere to obtain the ternary cathode material precursor; The inlet air temperature for the spray granulation process is 450℃~650℃, and the outlet air temperature is 100℃~150℃; the chemical formula of the ternary cathode material precursor is (Ni x Co y Y z )2O3, where 0 < x < 1, 0 ≤ y < 1, 0 < z < 1, x + y + z = 1, and Y includes Mn and / or Al.

17. A ternary cathode material precursor, characterized in that, The ternary cathode material precursor is prepared by the preparation method according to any one of claims 1-16.

18. The ternary cathode material precursor according to claim 17, characterized in that, The particle size D50 of the ternary cathode material precursor is 5μm~15μm.

19. A ternary cathode material, characterized in that, The ternary cathode material is obtained by mixing and sintering the ternary cathode material precursor as described in claim 17 or 18 with a lithium source.

20. A lithium-ion battery, characterized in that, The positive electrode of the lithium-ion battery includes the ternary positive electrode material as described in claim 19.