Hydroxyl cobalt oxide doped and method for preparing the same

Abstract

The application provides a doped cobalt oxyhydroxide and a preparation method thereof. The preparation method comprises the following steps: obtaining a mixed metal salt complex solution; mixing the first mixed metal salt complex solution with an alkali solution in an alkaline environment, introducing first oxygen gas, and performing a precipitation reaction under first stirring treatment and first alkaline conditions to obtain a seed solution; adding the remaining mixed metal salt complex solution and the alkali solution to the seed solution, introducing second oxygen gas, and performing crystal growth under second stirring treatment and second alkaline conditions to obtain a doped cobalt oxyhydroxide slurry; the flow rate of the second oxygen gas is lower than that of the first oxygen gas, the stirring speed of the second stirring treatment is lower than that of the first stirring treatment, and the pH value of the second alkaline conditions is lower than that of the first alkaline conditions. The doped cobalt oxyhydroxide with good sphericity, uniform particle size and high tap density can be prepared.

Description

Technical Field

[0001] This application belongs to the field of battery materials technology, and more specifically, relates to a doped cobalt hydroxyoxide and its preparation method. Background Technology

[0002] Lithium cobalt oxide (LCO) is a cathode material for lithium-ion batteries, used in high-capacity mobile phones, laptops, digital cameras, and other 3C electronic products. 3C batteries require high energy density, placing high demands on LCO cathode materials. Improving battery energy density by increasing the charging cut-off voltage and compaction density of LCO has two development trends: ① One is particle size variation, moving towards both large and small particle sizes, with large and small particles mixed in a certain proportion to increase compaction density; ② The other is doping, used to prepare high-voltage lithium cobalt oxide.

[0003] Cobalt tetroxide (Co3O4) is a precursor of lithium cobalt oxide. Its composition, morphology, and particle size significantly influence the physicochemical properties of lithium cobalt oxide, making it a key raw material for the development of high-voltage LCOs. Cathode material manufacturers, in collaboration with precursor producers, have jointly developed a wet doping technology: first, a wet co-precipitation process is performed to obtain a doped intermediate, which is then calcined to obtain doped cobalt tetroxide. Currently, there are two process systems for synthesizing wet doped intermediates: a carbonate system co-precipitation process and a hydroxide system (non-oxidizing and oxidizing) process. The carbonate system is used to prepare large-particle-size doped cobalt tetroxide; the small-particle-size precursor product is prepared using a carbonate and hydroxide oxidation (cobalt hydroxyl) system.

[0004] The wet co-precipitation synthesis of cobalt-doped intermediates using a carbonate system has two drawbacks: firstly, Al... 3+ With Co 2 + The significant differences in ionic radii and valences prevent the formation of solid solutions, causing aluminum to precipitate compounds independently, resulting in uneven Al distribution in cobalt carbonate. Secondly, in the carbonate system, some elements (such as Ni and Mg) precipitate incompletely, making precise control of doping levels difficult. Doping with other elements (such as Ni, Mn, and La) leads to significant internal stratification within the particles, resulting in lower tap density. While replacing the carbonate system with a cobalt hydroxyl system significantly improves doping uniformity, morphology and particle size are difficult to control. Cobalt hydroxyl particles growing above 10 μm are prone to fragmentation into smaller particles, hindering particle size growth. Summary of the Invention

[0005] Based on this, one objective of this application is to provide a method for preparing doped cobalt hydroxyl oxide, in order to solve the technical problems in the prior art where the morphology and particle size are difficult to control, and small particles are prone to break off when the cobalt hydroxyl oxide particle size grows to more than 10 μm, making it difficult to increase the particle size.

[0006] Another object of this application is to provide a doped cobalt hydroxyl oxide.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0008] A method for preparing doped cobalt hydroxyl oxide includes the following steps:

[0009] A mixed metal salt complex solution is obtained, and the mixed metal salt complex solution is divided into several portions. The mixed metal salt complex solution includes a first metal ion, a second metal ion, and a cobalt ion.

[0010] In an alkaline environment, the first mixed metal salt complex solution is mixed with an alkaline solution, and a first oxygen gas is introduced. Under the first stirring treatment and the first alkaline conditions, a precipitation reaction is carried out to obtain a seed crystal solution.

[0011] The remaining mixed metal salt complex solution and alkaline solution are added to the seed crystal solution, a second oxygen gas is introduced, and crystal growth is carried out under a second stirring treatment and a second alkaline condition to obtain a doped cobalt hydroxyl oxide slurry; wherein, the flow rate of the second oxygen gas is lower than that of the first oxygen gas, the stirring speed of the second stirring treatment is lower than that of the first stirring treatment, and the pH value of the second alkaline condition is lower than that of the first alkaline condition.

[0012] Cobalt hydroxy oxide slurry was subjected to solid-liquid separation, washing, and drying to obtain cobalt hydroxy oxide.

[0013] Optionally, the mixed metal salt complexing solution is prepared by mixing a first metal salt, a second metal salt, a cobalt salt, and a complexing agent, wherein the cobalt salt includes at least one of cobalt chloride, cobalt sulfate, and cobalt nitrate.

[0014] Optionally, the first metal salt is any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt; the second metal salt is any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt; and / or,

[0015] The first metal salt, the second metal salt, and the cobalt salt have the same anion.

[0016] Optionally, the first metal salt is a nickel salt, the second metal salt is a manganese salt, the complexing agent is disodium EDTA, and the mass ratio of nickel ions in the nickel salt, manganese ions in the manganese salt, disodium EDTA, and cobalt ions in the cobalt salt is (0.001-0.029):(0.001-0.029):(0.01-0.03):1.

[0017] Optionally, the total metal ion concentration of the mixed metal salt complex solution is 90 g / L-120 g / L.

[0018] Optionally, in an alkaline environment, the first mixed metal salt complex solution is mixed with an alkaline solution, oxygen gas is introduced, and a precipitation reaction is carried out under stirring to obtain a seed crystal solution. At least one of the following conditions must be met in this step:

[0019] The flow rate of the first oxygen gas is 120L / h-160L / h;

[0020] The mixing speed for the first mixing process is 600 rpm-650 rpm;

[0021] The pH of the first alkaline condition is 11.0-12.0;

[0022] The reaction temperature is 50℃-65℃.

[0023] Optionally, the seed particle size in the seed solution is 6μm-8μm.

[0024] Optionally, the method of adding the remaining mixed metal salt complex solution and alkaline solution to the seed crystal solution, and carrying out crystal growth under a second oxygen gas, a second stirring treatment, and a second alkaline condition includes the following steps:

[0025] The second mixed metal salt complex solution and alkaline solution were mixed with the seed solution to grow cobalt hydroxy oxide crystals in the first stage. Oxygen gas was introduced at a rate of 100 L / h-120 L / h, the stirring speed was 500 rpm-520 rpm, and the pH of the reaction system was 10.5-11.0 until the particle size of the cobalt hydroxy oxide crystals in the first stage reached 9 μm-11 μm, thus obtaining the cobalt hydroxy oxide slurry in the first stage.

[0026] The third mixed metal salt complex solution and alkaline solution were mixed with the first-stage doped cobalt hydroxy oxide slurry to grow second-stage doped cobalt hydroxy oxide crystals. Oxygen gas was introduced at a rate of 80 L / h-100 L / h, the stirring speed was 400 rpm-430 rpm, and the pH of the reaction system was 10.0-10.5 until the particle size of the second-stage doped cobalt hydroxy oxide crystals reached 12 μm-14 μm, thus obtaining the second-stage doped cobalt hydroxy oxide slurry.

[0027] The fourth mixed metal salt complex solution and alkaline solution were mixed with the second-stage doped cobalt hydroxyoxide slurry to grow third-stage doped cobalt hydroxyoxide crystals. Oxygen gas was introduced at a rate of 40 L / h-80 L / h, the stirring speed was 200 rpm-220 rpm, and the pH of the reaction system was 9.5-10.0 until the particle size of the third-stage doped cobalt hydroxyoxide crystals reached 15 μm-18 μm, thus obtaining the third-stage doped cobalt hydroxyoxide slurry.

[0028] Optionally, the first metal ion is nickel ion, and the second metal ion is manganese ion. The mass content of nickel in the doped cobalt hydroxyoxide is 0.07%-2%, and the mass content of manganese is 0.07%-2%. The nickel and manganese elements are basically uniformly distributed from the core to the outer layer in the doped cobalt hydroxyoxide, with a particle size D50 of 15μm-18μm, a spherical morphology, and a tap density of 2.2g / cm³. 3 -3.0g / cm 3 .

[0029] And, a doped cobalt hydroxyoxide, prepared using any of the methods described above for preparing doped cobalt hydroxyoxide.

[0030] 1. The beneficial effects of the preparation method of doped cobalt hydroxide provided in this application are as follows: The seed crystal synthesis stage is designed in an alkaline environment with oxygen gas introduction to fully oxidize the divalent cobalt to trivalent cobalt, that is, changing the original divalent plate-like cobalt hydroxide into trivalent coarse lath cobalt hydroxide, thus altering the particle packing mode. Combined with the stirring speed, the following objectives are achieved: firstly, to regulate the liquid flow, increase fluid shear force to prevent particle adhesion and growth; secondly, to accelerate the diffusion rate of reacting ions, allowing precipitated particles to quickly diffuse to the vacant parts of the particles. The high surface energy in the vacant parts promotes preferential packing and growth, resulting in densely packed, well-dispersed seed crystal particles. The seed crystal is mixed with a mixed metal salt complex solution and an alkaline solution for crystal growth. During the growth process, by lowering the pH value of the reaction system and reducing the stirring speed, a new vertical plate-like framework grows on the outer layer of the seed crystal, obtaining a rough and porous morphology. This ensures that the growing particles maintain a high surface energy, allowing for continuous adsorption and growth. Reducing the airflow reduces the oxygen content of the main element, cobalt. The degree of oxidation alters the composition of the precipitate, changing the original core trivalent cobalt hydroxide phase to trivalent cobalt hydroxide and cobalt tetroxide. This refines the primary particles, and newly generated small precipitate particles fill the pores of the particles, promoting crystal repair and growth. This results in large-particle-size doped cobalt hydroxide with good sphericity, uniform particle size, and high tap density. Compared with existing technologies, the preparation method of doped cobalt hydroxide in this application can prepare large-particle-size doped cobalt hydroxide with good sphericity, uniform particle size, and high tap density by adjusting the flow rate of oxygen gas, stirring speed, and pH during the seed crystal generation and crystal growth stages. Moreover, the preparation method is simple and easy to control, which is conducive to industrial promotion.

[0031] 2. The doped cobalt oxide provided in this application has a uniform distribution of dopant elements in cobalt oxide without segregation, and the morphology consists of spherical particles of uniform size with high tap density. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0033] Figure 1Scanning electron microscopy of cobalt hydroxyoxide doped with silica prepared in Example 1 of this application Figure 1 ;

[0034] Figure 2 Scanning electron microscopy of cobalt hydroxyoxide doped with silica prepared in Example 1 of this application Figure 2 ;

[0035] Figure 3 This is a distribution diagram of nickel in the doped cobalt hydroxyl oxide prepared in Example 1 of this application;

[0036] Figure 4 This is a distribution diagram of manganese in the doped cobalt hydroxyoxide prepared in Example 1 of this application;

[0037] Figure 5 The image shows a scanning electron microscope (SEM) image of cobalt hydroxyoxide prepared in Comparative Example 1. Detailed Implementation

[0038] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0039] An embodiment of this application provides a method for preparing doped cobalt hydroxyl oxide, comprising the following steps:

[0040] S10: Obtain a mixed metal salt complex solution, divide the mixed metal salt complex solution into several portions, the mixed metal salt complex solution includes a first metal ion, a second metal ion and a cobalt ion.

[0041] Understandably, the metal element in the first metal ion and the second metal ion is the metal element to be doped. The preparation method of doped cobalt hydroxyoxide in this application embodiment can include at least one of nickel, manganese, magnesium, zirconium, yttrium, and lanthanum, all of which can produce large-particle-size doped cobalt hydroxyoxide with good sphericity, uniform particle size, and high tap density. When only one metal is used for doping, the first metal ion and the second metal ion are the same; when multiple metals are used for doping, the first metal ion and the second metal ion are different.

[0042] In some embodiments, the mixed metal salt complex solution is prepared by mixing a first metal salt, a second metal salt, a cobalt salt, and a complexing agent. The first metal salt can be any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt, and the second metal salt can be any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt.

[0043] In some embodiments, the metal elements doped with cobalt hydroxyoxide are nickel and manganese. When the doping metals are nickel and manganese, cobalt hydroxyoxide can be used to prepare lithium cobalt oxide, a battery cathode material, and the electrical properties of the prepared lithium cobalt oxide can be significantly improved. In this case, the first metal ion is nickel ion and the second metal ion is manganese ion. The method for obtaining a mixed metal salt complex solution includes the following steps:

[0044] Nickel salt, manganese salt, complexing agent and cobalt salt are mixed to obtain a mixed metal salt complex solution.

[0045] Optionally, the complexing agent is disodium EDTA, and the mass ratio of nickel ions in the nickel salt, manganese ions in the manganese salt, disodium EDTA, and cobalt ions in the cobalt salt is (0.001-0.029):(0.001-0.029):(0.01-0.03):1. Disodium EDTA can provide sufficient coordination complexation of nickel ions, manganese ions, and cobalt ions to initially introduce nickel and manganese doping.

[0046] Optionally, the total metal ion concentration of the mixed metal salt complex solution is 90 g / L-120 g / L. This ion concentration allows for rapid diffusion during the reaction, which helps to regulate the reaction rate with sodium hydroxide and avoids the problem of excessively high concentrations leading to rapid nucleation.

[0047] Optionally, the cobalt salt is one of cobalt chloride, cobalt sulfate, or cobalt nitrate. These cobalt salts are soluble in water and can react with disodium EDTA in aqueous solution. Understandably, to avoid introducing other impurities, the first metal salt, the second metal salt, and the cobalt salt have the same anion. Therefore, when the first metal is nickel and the second metal is manganese, the corresponding nickel salts are nickel chloride, nickel sulfate, or nickel nitrate, and the manganese salts are manganese chloride, manganese sulfate, or manganese nitrate. These nickel and manganese salts are all soluble in water, and in aqueous solution, nickel and manganese ions can complex with disodium EDTA.

[0048] S20: In an alkaline environment, the first mixed metal salt complex solution is mixed with an alkaline solution, and a first oxygen gas is introduced. Under the first stirring treatment and the first alkaline conditions, a precipitation reaction is carried out to obtain a seed crystal solution.

[0049] The seed crystal synthesis stage is designed to be carried out in an alkaline environment with oxygen gas to fully oxidize the divalent cobalt into trivalent cobalt, that is, to change the original divalent plate-like cobalt hydroxide into trivalent coarse plate-like cobalt hydroxide, thereby changing the particle packing mode. Combined with the stirring speed, the following objectives are achieved: first, to regulate the flow of the liquid and increase the fluid shear force to prevent particle adhesion and growth; second, to accelerate the diffusion rate of reaction ions, so that the precipitated particles can quickly diffuse to the vacant parts of the particles. The surface energy of the vacant parts is high, so they preferentially accumulate and grow, thereby obtaining dense and well-dispersed seed crystal particles.

[0050] In this embodiment, the alkaline environment refers to an alkaline solution environment. The first mixed metal salt complex solution reacts with the alkaline solution in an alkaline solution environment. The pH of the reaction system is 11.0-12.0, that is, the pH of the first alkaline condition is 11.0-12.0.

[0051] One method to create an alkaline environment is to use pure water as the base solution, add a small amount of sodium hydroxide to adjust the pH of the solution to 11.0-12.0, use pure water as the base solution, add a mixed metal salt complex solution and an alkaline solution and mix them. The base solution can increase the dispersibility of the mixed metal salt complex solution and the alkaline solution and adjust the concentration of the mixed metal salt complex solution and the alkaline solution.

[0052] Optionally, the alkaline solution is a sodium hydroxide solution of 200 g / L-400 g / L. The sodium hydroxide solution of this concentration is combined with the total metal ion concentration of the mixed metal salt complex solution of 90 g / L-120 g / L. By adjusting the oxygen gas flow rate, stirring speed, pH and reaction temperature, better doped cobalt hydroxyl oxide seed crystals can be obtained.

[0053] Optionally, the conditions in step S20 must satisfy at least one of the following:

[0054] The flow rate of the first oxygen gas is 120L / h-160L / h;

[0055] The mixing speed for the first mixing process is 600 rpm-650 rpm;

[0056] The pH of the first alkaline condition is 11.0-12.0;

[0057] The reaction temperature is 50℃-65℃.

[0058] By utilizing a high pH value of 11.0-12.0 and a large flow rate of oxygen gas, a large flow rate of oxygen gas is introduced during the wet synthesis process to further ensure that divalent cobalt is fully oxidized to trivalent cobalt. Combined with a high stirring speed to regulate the flow of the liquid and accelerate the diffusion rate of reaction ions, dense core and well-dispersed doped cobalt hydroxyl oxide seed particles are obtained.

[0059] In a preferred embodiment, the conditions in step S20 simultaneously satisfy the following: the flow rate of the first oxygen gas is 120 L / h-160 L / h; the stirring speed of the first stirring treatment is 600 rpm-650 rpm; the pH of the first alkaline condition is 11.0-12.0; and the reaction temperature is 50℃-65℃.

[0060] Optionally, the seed crystals in the seed solution have a particle size of 6μm-8μm. The doped cobalt hydroxyoxide seed crystals of this size have a dense core and moderate particle size, providing a good structural basis for the subsequent growth of crystal particles.

[0061] Understandably, the oxygen gas can be a mixture of inert gas and oxygen or air, etc. Considering convenience and economic benefits, air can be used as the oxygen gas.

[0062] S30: Add the remaining mixed metal salt complex solution and alkaline solution to the seed crystal solution, introduce a second oxygen gas, and carry out crystal growth under a second stirring treatment and a second alkaline condition to obtain a doped cobalt hydroxyl oxide slurry; wherein, the flow rate of the second oxygen gas is lower than that of the first oxygen gas, the stirring speed of the second stirring treatment is lower than that of the first stirring treatment, and the pH value of the second alkaline condition is lower than that of the first alkaline condition.

[0063] Crystal growth is achieved by mixing seed crystals with a mixed metal salt complex solution and an alkaline solution. During growth, the pH of the reaction system is lowered and the stirring speed is reduced, causing a new vertical lamellar framework to grow on the outer layer of the seed crystal, resulting in a rough and porous morphology. This ensures that the growing particles maintain a high surface energy, allowing for continuous adsorption and growth. Reducing the airflow rate decreases the oxidation degree of the main element, cobalt, altering the composition of the precipitate product. The original core trivalent cobalt hydroxyl phase transforms into trivalent cobalt hydroxyl and cobalt tetroxide, refining the primary particles. Newly generated small precipitate particles fill the pores, promoting crystal repair and growth. This results in large-particle-size doped cobalt hydroxyl oxide with good sphericity, uniform particle size, and high tap density.

[0064] Optionally, step S30 includes the following steps:

[0065] S31: The second mixed metal salt complex solution and alkaline solution are mixed with the seed solution to grow cobalt hydroxy oxide crystals in the first stage. Oxygen gas is introduced at a rate of 100 L / h-120 L / h, the stirring speed is 500 rpm-520 rpm, and the pH of the reaction system is 10.5-11.0 until the particle size of the cobalt hydroxy oxide crystals in the first stage reaches 9 μm-11 μm, and a cobalt hydroxy oxide slurry in the first stage is obtained.

[0066] S32: The third mixed metal salt complex solution and alkaline solution are mixed with the first-stage doped cobalt hydroxy oxide slurry to grow second-stage doped cobalt hydroxy oxide crystals. Oxygen gas is introduced at a rate of 80 L / h-100 L / h, the stirring speed is 400 rpm-430 rpm, and the pH of the reaction system is 10.0-10.5 until the particle size of the second-stage doped cobalt hydroxy oxide crystals reaches 12 μm-14 μm, thus obtaining the second-stage doped cobalt hydroxy oxide slurry.

[0067] S33: The fourth part of the mixed metal salt complex solution and alkaline solution is mixed with the second-stage doped cobalt hydroxy oxide slurry to grow third-stage doped cobalt hydroxy oxide crystals. Oxygen gas is introduced at a rate of 40 L / h-80 L / h, the stirring speed is 200 rpm-220 rpm, and the pH of the reaction system is 9.5-10.0 until the particle size of the third-stage doped cobalt hydroxy oxide crystals reaches 15 μm-18 μm, thus obtaining the third-stage doped cobalt hydroxy oxide slurry.

[0068] The seed crystals are grown in three stages. During each stage of growth, the pH value and stirring speed of the reaction system are adjusted to ensure that a new vertical plate-like framework grows on the outer layer of the crystal in each stage. This ensures that the growing crystal particles maintain a high surface energy, allowing the crystal particles to continue to adsorb and grow.

[0069] During the three-stage growth process, the oxygen gas flow rate is gradually reduced in each stage, and the oxidation degree of the main element cobalt is gradually reduced in each stage, so that the composition of the precipitated product changes in each stage, promoting the repair and growth of the crystal in each stage, and further ensuring the acquisition of large-particle-size doped cobalt oxide with good sphericity, uniform particle size and high tap density.

[0070] Understandably, the number of growth stages can be selected based on the required cobalt hydroxyoxide particle size, either by performing only one stage or only two stages of growth to obtain cobalt hydroxyoxide of the corresponding particle size.

[0071] S40: The doped cobalt hydroxy oxide slurry is subjected to solid-liquid separation, washing and drying to obtain doped cobalt hydroxy oxide.

[0072] Optionally, the drying temperature is 700℃-800℃.

[0073] In some embodiments, when the first metal ion is nickel ion and the second metal ion is manganese ion, the mass content of nickel in the doped cobalt hydroxyoxide is 0.07%-2%, and the mass content of manganese is 0.07%-2%. The nickel and manganese elements are basically uniformly distributed from the core to the outer layer in the doped cobalt hydroxyoxide, with a particle size D50 of 15μm-18μm, a spherical morphology, and a tap density of 2.2 g / cm³. 3 -3.0g / cm 3 .

[0074] Compared with the prior art, the preparation method of doped cobalt hydroxyl oxide provided in this application can prepare large-particle-size doped cobalt hydroxyl oxide with good sphericity, uniform particle size and high tap density by adjusting the flow rate of oxygen gas, stirring speed and pH in the seed generation stage and the crystal growth stage. Moreover, the preparation method is simple and easy to control, which is conducive to industrial promotion.

[0075] This application also provides a doped cobalt hydroxyl oxide, prepared using the above-described method for preparing doped cobalt hydroxyl oxide. The doped cobalt hydroxyl oxide provided in this application has a uniform distribution of the dopant element within the cobalt oxide, without segregation, and exhibits a uniform spherical particle morphology with high tap density.

[0076] The following examples illustrate the doped cobalt hydroxyl oxide, its preparation method, its products, and the properties of the products.

[0077] Example 1

[0078] The preparation method of doped cobalt hydroxyl oxide in this embodiment includes the following steps:

[0079] S01: Mix cobalt sulfate, nickel sulfate, manganese sulfate, disodium EDTA and pure water, with the mass ratio of nickel ions in nickel sulfate, manganese ions in manganese sulfate, disodium EDTA and cobalt ions in cobalt sulfate being 0.001:0.001:0.01:1, to prepare a mixed metal salt complex solution with a metal ion concentration of 90 g / L.

[0080] SO2: Mix sodium hydroxide with pure water to prepare a sodium hydroxide solution with a concentration of 200 g / L.

[0081] S03: Inject pure water into the reactor as the base liquid, start stirring at 600 rpm, heat to 60℃, introduce air at a flow rate of 120 L / h, and add a small amount of sodium hydroxide solution with a concentration of 200 g / L to adjust the pH to 11.0; add the first mixed metal salt complex solution and sodium hydroxide solution to the reactor at the same time to carry out the precipitation reaction until the particle size of the precipitate reaches 6.1 μm, and obtain the seed crystal solution.

[0082] S04: Transfer the seed solution to the growth vessel, and add the second part of the mixed metal salt complex solution and sodium hydroxide solution to carry out the first stage of growth. Adjust the stirring speed to 500 rpm, the air flow rate to 100 L / h, and the pH value of the reaction system to 10.5. When the particle size reaches 9.2 μm, the first stage of growth is completed, and the first stage doped cobalt hydroxyl oxide is obtained.

[0083] S05: Divide the first-stage doped cobalt hydroxyl oxide into two parts and transfer them into two growth reactors. Add the third part of the mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the second-stage growth. Adjust the stirring speed to 400 rpm, the air flow rate to 80 L / h, and the pH value of the reaction system to 10.0. When the particle size reaches 12.1 μm, the second-stage growth is completed, and the second-stage doped cobalt hydroxyl oxide is obtained.

[0084] S06: Divide the second-stage doped cobalt hydroxyl oxide into two parts and transfer them into four growth reactors. Add the fourth part of the mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the third-stage growth. Adjust the stirring speed to 200 rpm, the air flow rate to 40 L / h, and the pH value of the reaction system to 9.6. When the particle size reaches 15.1 μm, the third-stage growth is completed, and the third-stage doped cobalt hydroxyl oxide is obtained.

[0085] S07: The third-stage doped cobalt hydroxyl oxide is subjected to solid-liquid separation and washing, and then dried in a rotary kiln at 700°C to finally obtain large-particle-size doped cobalt hydroxyl oxide.

[0086] The obtained large-particle-size doped cobalt oxyhydroxide was tested and found to contain 72.8% cobalt by mass, 0.071% nickel, and 0.072% manganese by mass, with a median particle size D50 of 15.1 μm and a tap density of 2.43 g / cm³. 3 Scanning electron microscope image as follows Figure 1 and Figure 2 As shown, the cobalt hydroxyoxide-doped particles exhibit good sphericity and uniform particle size. For the distribution of doping elements, please refer to [link to relevant documentation]. Figure 3 and Figure 4 The nickel and manganese elements are evenly distributed.

[0087] Example 2

[0088] The preparation method of doped cobalt hydroxyl oxide in this embodiment includes the following steps:

[0089] S01: Cobalt sulfate, nickel sulfate, manganese sulfate, disodium EDTA and pure water are mixed, and the mass ratio of nickel ions in nickel sulfate, manganese ions in manganese sulfate, disodium EDTA and cobalt ions in cobalt sulfate is 0.0084:0.0168:0.02:1, to prepare a mixed metal salt complex solution with a metal ion concentration of 105 g / L.

[0090] SO2: Mix sodium hydroxide with pure water to prepare a sodium hydroxide solution with a concentration of 300 g / L.

[0091] S03: Inject pure water into the reactor as the base liquid, start stirring at 600 rpm, heat to 65℃, introduce air at a flow rate of 140 L / h, and add a small amount of sodium hydroxide solution with a concentration of 300 g / L to adjust the pH to 11.5; add the first mixed metal salt complex solution and sodium hydroxide solution to the reactor at the same time to carry out the precipitation reaction until the particle size of the precipitate reaches 7.0 μm, and obtain the seed crystal solution.

[0092] S04: Transfer the seed solution to the growth vessel, and add the second part of the mixed metal salt complex solution and sodium hydroxide solution to carry out the first stage of growth. Adjust the stirring speed to 500 rpm, the air flow rate to 120 L / h, and the pH value of the reaction system to 10.8. When the particle size reaches 10.3 μm, the first stage of growth is completed, and the first stage doped cobalt hydroxyl oxide is obtained.

[0093] S05: Divide the first-stage doped cobalt hydroxyl oxide into two parts and transfer them into two growth reactors. Add a third part of the mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the second-stage growth. Adjust the stirring speed to 400 rpm, the air flow rate to 100 L / h, and the pH value of the reaction system to 10.2. When the particle size reaches 13.2 μm, the second-stage growth is completed, and the second-stage doped cobalt hydroxyl oxide is obtained.

[0094] S06: Divide the second-stage doped cobalt hydroxyl oxide into two parts and transfer them into four growth reactors. Add the fourth part of the mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the third-stage growth. Adjust the stirring speed to 200 rpm, the air flow rate to 60 L / h, and the pH value of the reaction system to 9.8. When the particle size reaches 16.7 μm, the third-stage growth is completed, and the third-stage doped cobalt hydroxyl oxide is obtained.

[0095] S07: The third-stage doped cobalt hydroxyl oxide is subjected to solid-liquid separation and washing, and then dried in a rotary kiln at 150°C to finally obtain large-particle-size doped cobalt hydroxyl oxide.

[0096] The obtained large-particle-size doped cobalt oxyhydroxide was tested and found to contain 71.4% cobalt by mass, 0.6% nickel, and 1.2% manganese by mass, with a median particle size D50 of 16.6 μm and a tap density of 2.73 g / cm³. 3 .

[0097] Example 3

[0098] The preparation method of doped cobalt hydroxyl oxide in this embodiment includes the following steps:

[0099] S01: Mix cobalt sulfate, nickel sulfate, manganese sulfate, disodium EDTA and pure water, with the mass ratio of nickel ions in nickel sulfate, manganese ions in manganese sulfate, disodium EDTA and cobalt ions in cobalt sulfate being 0.018:0.06:0.06:1, to prepare a mixed metal salt complex solution with a metal ion concentration of 120 g / L.

[0100] SO2: Mix sodium hydroxide with pure water to prepare a sodium hydroxide solution with a concentration of 400 g / L.

[0101] S03: Inject pure water into the reactor as the base liquid, start stirring at 600 rpm, heat to 70℃, introduce air at a flow rate of 160 L / h, and add a small amount of sodium hydroxide solution with a concentration of 400 g / L to adjust the pH to 12.0; add the first mixed metal salt complex solution and sodium hydroxide solution to the reactor at the same time to carry out the precipitation reaction until the particle size of the precipitate reaches 7.9 μm, and obtain the seed crystal solution.

[0102] S04: Transfer the seed solution to the growth vessel, and add the second part of the mixed metal salt complex solution and sodium hydroxide solution to carry out the first stage of growth. Adjust the stirring speed to 500 rpm, the air flow rate to 120 L / h, and the pH value of the reaction system to 10.9. When the particle size reaches 10.9 μm, the first stage of growth is completed, and the first stage doped cobalt hydroxyl oxide is obtained.

[0103] S05: Divide the first-stage doped cobalt hydroxyl oxide into two parts and transfer them into two growth reactors. Add a third part of the mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the second-stage growth. Adjust the stirring speed to 400 rpm, the air flow rate to 100 L / h, and the pH value of the reaction system to 10.5. When the particle size reaches 13.9 μm, the second-stage growth is completed, and the second-stage doped cobalt hydroxyl oxide is obtained.

[0104] S06: Divide the second-stage doped cobalt hydroxyl oxide into two parts and transfer them into four growth vessels. Add the fourth part of the mixed metal salt complex solution and sodium hydroxide solution to each vessel to carry out the third-stage growth. Adjust the stirring speed to 200 rpm, the air flow rate to 80 L / h, and the pH value of the reaction system to 9.9. When the particle size reaches 17.8 μm, the third-stage growth is completed, and the third-stage doped cobalt hydroxyl oxide is obtained.

[0105] S07: The 3-stage doped cobalt hydroxyl oxide is subjected to solid-liquid separation and washing, and then dried in a rotary kiln at 200°C to finally obtain large-particle-size doped cobalt hydroxyl oxide.

[0106] The obtained large-particle-size doped cobalt oxyhydroxide was tested and found to contain 69.1% cobalt by mass, 1.96% nickel, and 2.0% manganese by mass, with a median particle size D50 of 17.9 μm and a tap density of 2.85 g / cm³. 3 .

[0107] Comparative Example 1

[0108] The preparation method of doped cobalt hydroxyl oxide in this embodiment includes the following steps:

[0109] S01: Mix cobalt sulfate, nickel sulfate, manganese sulfate, disodium EDTA and pure water, with the mass ratio of nickel ions in nickel sulfate, manganese ions in manganese sulfate, disodium EDTA and cobalt ions in cobalt sulfate being 0.001:0.001:0.01:1, to prepare a mixed metal salt complex solution with a metal ion concentration of 90 g / L.

[0110] SO2: Mix sodium hydroxide with pure water to prepare a sodium hydroxide solution with a concentration of 200 g / L.

[0111] S03: Inject pure water into the reactor as the base liquid, start stirring at 600 rpm, heat to 60℃, introduce air at a flow rate of 120 L / h, and add a small amount of sodium hydroxide solution with a concentration of 200 g / L to adjust the pH to 11.0; add the first mixed metal salt complex solution and sodium hydroxide solution to the reactor at the same time to carry out the precipitation reaction until the particle size of the precipitate reaches 6.1 μm, and obtain the seed crystal solution.

[0112] S04: Transfer the seed solution to the growth vessel, and add the second part of the mixed metal salt complex solution and sodium hydroxide solution to carry out the first stage growth. The stirring speed is 600 rpm, the air flow rate is 120 L / h, and the pH value of the reaction system is adjusted to 10.5. When the particle size reaches 9.2 μm, the first stage growth is completed, and the first stage doped cobalt hydroxyl oxide is obtained.

[0113] S05: Divide the first-stage doped cobalt hydroxyl oxide into two parts and transfer them into two growth reactors. Add a third part of mixed metal salt complex solution and sodium hydroxide solution to each reactor to carry out the second-stage growth. The stirring speed is 600 rpm, the air flow rate is adjusted to 120 L / h, and the pH value of the reaction system is adjusted to 10.0. When the particle size reaches 12.1 μm, the second-stage growth is completed, and the second-stage doped cobalt hydroxyl oxide is obtained.

[0114] S06: Divide the second-stage doped cobalt hydroxyl oxide into two parts and transfer them into four growth vessels. Add the fourth part of the mixed metal salt complex solution and sodium hydroxide solution to each vessel to carry out the third-stage growth. Adjust the stirring speed to 600 rpm, the air flow rate to 120 L / h, and the pH value of the reaction system to 9.6. When the particle size reaches 13.1 μm, the third-stage growth is completed, and the third-stage doped cobalt hydroxyl oxide is obtained.

[0115] S07: The third-stage doped cobalt hydroxyl oxide is subjected to solid-liquid separation and washing, and then dried in a rotary kiln at 700°C to finally obtain large-particle-size doped cobalt hydroxyl oxide.

[0116] The obtained large-particle-size doped cobalt oxyhydroxide was tested and found to contain 72.79% cobalt by mass, 0.070% nickel, and 0.072% manganese by mass, with a median particle size D50 of 12.9 μm and a tap density of 2.57 g / cm³.3 Scanning electron microscope image as follows Figure 5 As shown, the particle size of cobalt hydroxyoxide doped with it is not uniform.

[0117] The preparation methods of Comparative Example 1 and Example 1 are mostly the same. The difference is that the stirring speed and air flow rate in steps S03-S06 of Comparative Example 1 are the same, while the stirring speed and air flow rate in steps S03-S06 of Example 1 are gradually reduced. Compared with the doped cobalt oxide prepared in Comparative Example 1, the doped cobalt oxide prepared in Example 1 has better sphericity and more uniform particle size.

[0118] The doped cobalt oxide prepared in Examples 1 to 3 has a large particle size, good sphericity, uniform particle size, and high tap density.

[0119] Therefore, the preparation method of doped cobalt hydroxyoxide in this application controls the growth morphology of doped cobalt hydroxyoxide particles by controlling the pH value, stirring speed, and oxygen gas flow rate of the reaction system in the three stages of seed growth and crystal growth, and gradually reducing the pH value, stirring speed, and oxygen gas flow rate, thus obtaining large-particle-size doped cobalt hydroxyoxide with good sphericity, uniform particle size, and high tap density.

[0120] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing cobalt oxide doped with hydroxyl groups, characterized in that: Includes the following steps: A mixed metal salt complex solution is obtained, and the mixed metal salt complex solution is divided into several portions, wherein the mixed metal salt complex solution includes a first metal ion, a second metal ion, and a cobalt ion; In an alkaline environment, the first portion of the mixed metal salt complex solution is mixed with an alkaline solution, a first oxygen gas is introduced, and a precipitation reaction is carried out under a first stirring treatment and a first alkaline condition to obtain a seed crystal solution. The remaining mixed metal salt complex solution and alkaline solution are added to the seed crystal solution, a second oxygen gas is introduced, and crystal growth is carried out under a second stirring treatment and a second alkaline condition to obtain a cobalt hydroxyl oxide slurry; wherein, the flow rate of the second oxygen gas is lower than that of the first oxygen gas, the stirring speed of the second stirring treatment is lower than that of the first stirring treatment, and the pH value of the second alkaline condition is lower than that of the first alkaline condition. The cobalt hydroxyl oxide doped slurry was subjected to solid-liquid separation, washing, and drying to obtain spherical particles with a particle size D50 of 15 μm-18 μm and uniform morphology, and a tap density of 2.2 g / cm³. 3 -3.0g / cm 3 Cobalt oxide doped with hydroxyl groups; The conditions in the step of obtaining the seed solution are satisfied as follows: The flow rate of the first oxygen gas is 120 L / h - 160 L / h; The stirring speed for the first stirring process is 600 rpm-650 rpm; The pH of the first alkaline condition is 11.0-12.0; The reaction temperature is 50℃-65℃; The method of adding the remaining mixed metal salt complex solution and alkaline solution to the seed crystal solution, introducing a second oxygen gas, and carrying out crystal growth under a second stirring treatment and a second alkaline condition includes the following steps: The second portion of the mixed metal salt complex solution and alkaline solution was mixed with the seed solution to grow cobalt hydroxy oxide crystals in the first stage. Oxygen gas was introduced at a rate of 100 L / h-120 L / h, the stirring speed was 500 rpm-520 rpm, and the pH of the reaction system was 10.5-11.0 until the particle size of the cobalt hydroxy oxide crystals in the first stage reached 9 μm-11 μm, thus obtaining a cobalt hydroxy oxide slurry in the first stage. The third portion of the mixed metal salt complex solution and alkaline solution was mixed with the first-stage doped cobalt hydroxy oxide slurry to grow second-stage doped cobalt hydroxy oxide crystals. Oxygen gas was introduced at a rate of 80 L / h-100 L / h, the stirring speed was 400 rpm-430 rpm, and the pH of the reaction system was 10.0-10.5 until the particle size of the second-stage doped cobalt hydroxy oxide crystals reached 12 μm-14 μm, thus obtaining the second-stage doped cobalt hydroxy oxide slurry. The fourth portion of the mixed metal salt complex solution and alkaline solution was mixed with the second-stage doped cobalt hydroxyoxide slurry to grow third-stage doped cobalt hydroxyoxide crystals. Oxygen gas was introduced at a rate of 40 L / h-80 L / h, the stirring speed was 200 rpm-220 rpm, and the pH of the reaction system was 9.5-10.0 until the particle size of the third-stage doped cobalt hydroxyoxide crystals reached 15 μm-18 μm, thus obtaining the third-stage doped cobalt hydroxyoxide slurry.

2. The method for preparing doped cobalt hydroxyl oxide as described in claim 1, characterized in that: The mixed metal salt complexing solution is prepared by mixing a first metal salt, a second metal salt, a cobalt salt, and a complexing agent, wherein the cobalt salt includes at least one of cobalt chloride, cobalt sulfate, and cobalt nitrate.

3. The method for preparing doped cobalt hydroxyl oxide as described in claim 2, characterized in that: The first metal salt is any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt; the second metal salt is any one of nickel salt, manganese salt, magnesium salt, zirconium salt, yttrium salt, and lanthanum salt; and / or, The first metal salt, the second metal salt, and the cobalt salt have the same anion.

4. The method for preparing doped cobalt hydroxyl oxide as described in claim 2 or 3, characterized in that: The first metal salt is a nickel salt, the second metal salt is a manganese salt, the complexing agent is disodium EDTA, and the mass ratio of nickel ions in the nickel salt, manganese ions in the manganese salt, disodium EDTA, and cobalt ions in the cobalt salt is (0.001-0.029):(0.001-0.029):(0.01-0.03):

1.

5. The method for preparing doped cobalt hydroxyl oxide according to any one of claims 1-3, characterized in that: The total metal ion concentration of the mixed metal salt complex solution is 90 g / L-120 g / L.

6. The method for preparing doped cobalt hydroxyl oxide according to any one of claims 1-3, characterized in that: The seed crystals in the seed solution have a particle size of 6μm-8μm.

7. The method for preparing doped cobalt hydroxyl oxide according to any one of claims 1-3, characterized in that: The first metal ion is a nickel ion, and the second metal ion is a manganese ion; the mass content of nickel in the doped cobalt hydroxyoxide is 0.07%-2%, and the mass content of manganese is 0.07%-2%, and the nickel and manganese elements are basically uniformly distributed from the core to the outer layer in the doped cobalt hydroxyoxide.

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