A nickel-cobalt-manganese hydroxide precursor of a radial porous structure and a preparation method thereof

Abstract

The application discloses a nickel-cobalt-manganese hydroxide precursor with a radial porous structure and a preparation method thereof, and belongs to the technical field of lithium ion battery materials. x Co y Mn 1‑x‑y (OH)2, wherein 0.5≤x≤1 and 0≤y≤0.4; the nickel-cobalt-manganese hydroxide precursor has thin primary grains, the primary particles are interlaced with each other, form secondary particles with a radial loose porous internal structure, and bring a relatively high specific surface area to the secondary spherical particles; in the sintering process with a lithium source, the nickel-cobalt-manganese hydroxide precursor can provide more transmission channels for lithium ions, reduces the resistance of lithium ion embedding and extraction in the charging and discharging process, shortens the transmission distance of lithium ions, and improves the transmission rate.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery materials technology, specifically a radially porous nickel-cobalt-manganese hydroxide precursor and its preparation method. Background Technology

[0002] Lithium-ion batteries are widely used in portable electronic devices, energy storage, electric vehicles, and aerospace due to their numerous advantages, including high operating voltage, high energy density, low self-discharge rate, long cycle life, good safety performance, and no memory effect. Their excellent electrochemical performance largely depends on the performance of the cathode material, with ternary cathode materials being the most outstanding among various types.

[0003] Currently, the preparation of ternary cathode materials mainly involves the synthesis of ternary precursors and the synthesis of ternary oxides. First, the ternary precursor is synthesized, then it is mixed with a lithium source and sintered to obtain the ternary oxide cathode material. In this process, the physicochemical properties of the prepared ternary precursor directly affect the core electrochemical performance of the ternary cathode material. Currently, the main method for preparing the ternary precursor (nickel-cobalt-manganese hydroxide) is the co-precipitation method. This involves a nickel-cobalt-manganese metal salt solution reacting with a complexing agent and a precipitant under certain conditions to undergo a co-precipitation reaction, preparing spherical secondary particles. After aging, washing, drying, and sieving, the nickel-cobalt-manganese hydroxide precursor is finally obtained. The size, morphology, and internal structure of the precursor directly affect the performance of the lithium-ion battery ternary cathode material. Using a fine-grained whisker precursor with a loose and porous interior can significantly improve the specific capacity and rate performance of the material's electrochemical properties.

[0004] Invention patents CN111717941A and CN114105222A disclose a nickel-cobalt-manganese hydroxide with needle-like whiskers and its preparation method, and a nickel-cobalt-manganese hydroxide with a porous structure and its preparation method, respectively. Both methods control the whisker thickness of the particles by continuously adjusting the oxygen content in the reactor, resulting in a needle-like product with a loose, porous internal structure and a high specific surface area. However, the methods described in these two patents increase oxygen consumption and the complexity of process control, making it difficult to control the degree of oxidation of the materials.

[0005] The invention patent with announcement number CN115012036A discloses a fine-whiskered nickel-cobalt-manganese hydroxide with small particle size and its preparation method. The invention mainly obtains fine-whiskered nickel-cobalt-manganese hydroxide with small particle size by controlling the ammonia concentration, feed rate and rotation speed in the reactor. However, the ammonia concentration is controlled at 1 to 6 mol / L, which requires a high ammonia concentration and will increase the ammonia consumption to a certain extent. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a radially porous nickel-cobalt-manganese hydroxide precursor and its preparation method. The nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radially porous secondary particles, which ensures ion transport channels, increases the contact area of ​​the electrolyte, and solves the problem of material cracking during charging and discharging, thereby improving electrochemical performance.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a nickel-cobalt-manganese hydroxide precursor with a radially porous structure, the chemical formula of which is Ni x Co y Mn 1-x-y (OH)2, where 0.5≤x≤1, 0≤y≤0.4;

[0008] The nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlocking primary particles that form radial, loosely porous secondary particles.

[0009] In a preferred embodiment of the present invention, the nickel-cobalt-manganese hydroxide precursor has a microstructure of spherical particles with a specific surface area of ​​8.0–35 m². 2 / g, tap density is 1.5~2.5g / cm³ 3 Particle size distribution diameter ≤ 1.0.

[0010] In a preferred embodiment of the present invention, the nickel-cobalt-manganese hydroxide precursor has a microstructure of spherical particles with a specific surface area of ​​20–30 m². 2 / g, tap density is 1.6~2g / cm³ 3 The particle size distribution has a diameter of ≤0.7.

[0011] In a second aspect, the present invention provides a method for preparing the above-described radially porous nickel-cobalt-manganese hydroxide precursor, comprising the following steps:

[0012] (1) Prepare metal salt solutions by mixing nickel salt, cobalt salt and manganese salt with water according to the molar ratio of nickel, cobalt and manganese elements in the nickel cobalt manganese hydroxide precursor.

[0013] (2) Under a protective atmosphere, sodium hydroxide solution, ammonia solution and water are added to the reaction vessel to prepare a reaction base solution with a pH of 9.5 to 11.9 and an ammonia concentration of 0.5 to 10.0 g / L. Metal salt solution, sodium hydroxide solution and ammonia solution are introduced into the reaction vessel to carry out a co-precipitation reaction. When the particle size grows to 2.5 to 4.0 μm, the pH is adjusted to 10.7 to 11.6 and the reaction continues until the particle size is stable at 3.5 to 5.0 μm. The material is collected, centrifuged and dehydrated to obtain a seed filter cake.

[0014] (3) Under a protective atmosphere, sodium hydroxide solution, ammonia solution, and water are added to a reaction vessel to prepare a reaction base solution with a pH of 9.5–11.9 and an ammonia concentration of 0.5–10.0 g / L. Seed filter cake is added to the reaction vessel, and then metal salt solution, sodium hydroxide solution, and ammonia solution are introduced. The overflow valve is opened to allow the reaction to proceed. When the particle size grows to 5.0–7.0 μm, the overflow valve is closed, and the concentrator is started. The reaction continues until the particle size grows to 7.5–9 μm. The flow rate of the metal salt solution is adjusted, and the reaction continues until the particle size grows to 9.2–15.0 μm. The material is collected, aged, washed, dried, and sieved to obtain a radially porous nickel-cobalt-manganese hydroxide precursor. As a preferred embodiment of the present invention, the nickel salt includes at least one of nickel sulfate, nickel nitrate, and nickel chloride; and / or

[0015] The cobalt salt includes at least one of cobalt sulfate, cobalt nitrate, and cobalt chloride; and / or

[0016] The manganese salt includes at least one of manganese sulfate, manganese nitrate, and manganese chloride.

[0017] In a preferred embodiment of the present invention, the total metal ion concentration of the metal salt solution is 0.5 to 4 mol / L.

[0018] In a preferred embodiment of the present invention, the molar concentration of the sodium hydroxide solution is 0.5–14 mol / L, and the molar concentration of the ammonia solution is 0.5–14 mol / L.

[0019] In a preferred embodiment of the present invention, the flow rate of the metal salt solution in step (2) is 20-60 L / h, the flow rate of the sodium hydroxide solution is 8-25 L / h, and the flow rate of the ammonia solution is 0.5-4 L / h.

[0020] In a preferred embodiment of the present invention, the flow rate of the metal salt solution in step (3) is 20-60 L / h, the flow rate of the sodium hydroxide solution is 4-15 L / h, and the flow rate of the ammonia solution is 0-0.8 L / h.

[0021] As a preferred embodiment of the present invention, the flow rate of the metal salt solution in step (3) is adjusted to 40-50 L / h.

[0022] The beneficial effects of the present invention are as follows: (1) The nickel cobalt manganese hydroxide precursor of the present invention has thin primary grains and interlaced primary particles to form radially porous secondary particles, which bring a relatively high specific surface area to the secondary spherical particles. During the sintering process with the lithium source, it can provide more transport channels for lithium ions. At the same time, it reduces the resistance to lithium ion insertion and extraction during charging and discharging, shortens the lithium ion transport distance, and improves the transport rate. In addition, the nickel cobalt manganese hydroxide precursor also has abundant pores. On the one hand, the abundant pores can promote the penetration of electrolyte into the material to a certain extent. On the other hand, the abundant pores can also alleviate the volume strain generated in the material during charging and discharging to a certain extent, improve the structural stability of the material, so as to improve the specific capacity and rate performance of the material. (2) In the preparation process of this invention, a loose and porous radial fine whisker nickel cobalt manganese hydroxide precursor can be prepared by using ammonia-free or low ammonia process conditions, which can effectively reduce the consumption of ammonia water, which is conducive to achieving green, environmentally friendly, safe production and reducing production costs; at the same time, reducing the amount of ammonia water used can reduce the wastewater treatment process and reduce wastewater treatment costs; (3) This invention adopts the seeding method, and the ammonia concentration gradually decreases to 0-0.8 g / L during the overflow growth-concentration growth process. This seeding and gradual decrease in ammonia concentration control helps to prepare a radial ternary precursor material with a compact core and a loose and porous outer ring, which ensures the ion transport channel, increases the contact area of ​​the electrolyte, and solves the problem of material cracking during charging and discharging, thereby improving the electrochemical performance. Attached Figure Description

[0023] Figure 1 SEM image of the precursor prepared in Example 1;

[0024] Figure 2 This is a cross-sectional view of the precursor prepared in Example 1;

[0025] Figure 3 Here is a SEM image of the precursor prepared in Comparative Example 1;

[0026] Figure 4 This is a cross-sectional view of the precursor prepared in Comparative Example 1. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0029] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0030] In this invention, there are no particular limitations on the specific dispersion and stirring methods.

[0031] Unless otherwise specified, all reagents or instruments used in this invention are commercially available products.

[0032] This invention provides a radially porous nickel-cobalt-manganese hydroxide precursor, the chemical formula of which is Ni. x Co y Mn 1-x-y (OH)2, where 0.5≤x≤1, 0≤y≤0.4;

[0033] The nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlocking primary particles that form radial, loosely porous secondary particles.

[0034] The nickel-cobalt-manganese hydroxide precursor of this invention has thin primary grains with interwoven primary particles forming radially porous secondary particles. This results in a relatively high specific surface area for the secondary spherical particles, providing more transport channels for lithium ions during sintering with the lithium source. Simultaneously, it reduces the resistance to lithium ion insertion and extraction during charging and discharging, shortening the lithium ion transport distance and increasing the transport rate. Furthermore, the nickel-cobalt-manganese hydroxide precursor also possesses abundant pores. These pores promote electrolyte penetration into the material and alleviate volumetric strain during charging and discharging, improving the material's structural stability and ultimately enhancing its specific capacity and rate performance.

[0035] The nickel-cobalt-manganese hydroxide precursor has a compact core and a loose, porous outer ring, arranged radially. This ensures ion transport channels, increases the contact area with the electrolyte, and solves the problem of material cracking during charging and discharging, thus contributing to improved electrochemical performance.

[0036] In one embodiment, the nickel-cobalt-manganese hydroxide precursor has a microstructure of near-spherical particles with a specific surface area of ​​8.0–35 m². 2 / g, tap density is 1.5~2.5g / cm³ 3 Particle size distribution diameter ≤ 1.0.

[0037] Among them, the particle size distribution distance K90 = (D90-D10) / D50, and D90, D50 and D10 were all measured by laser particle size analysis diffraction method; the tap density was measured by tap density meter; and the specific surface area was measured by gas adsorption BET method.

[0038] In one embodiment, the nickel-cobalt-manganese hydroxide precursor has a microstructure of near-spherical particles with a specific surface area of ​​20–30 m². 2 / g, tap density is 1.6~2g / cm³ 3 The particle size distribution has a diameter of ≤0.7.

[0039] An embodiment of the present invention provides a method for preparing the above-described radially porous nickel-cobalt-manganese hydroxide precursor, comprising the following steps:

[0040] (1) Prepare metal salt solutions by mixing nickel salt, cobalt salt and manganese salt with water according to the molar ratio of nickel, cobalt and manganese elements in the nickel cobalt manganese hydroxide precursor.

[0041] (2) Under a protective atmosphere, sodium hydroxide solution, ammonia solution and water are added to the reaction vessel to prepare a reaction base solution with a pH of 9.5 to 11.9 and an ammonia concentration of 0.5 to 10.0 g / L. Metal salt solution, sodium hydroxide solution and ammonia solution are introduced into the reaction vessel to carry out a co-precipitation reaction. When the particle size grows to 2.5 to 4.0 μm, the pH is adjusted to 10.7 to 11.6 and the reaction continues until the particle size is stable at 3.5 to 5.0 μm. The material is collected, centrifuged and dehydrated to obtain a seed filter cake.

[0042] (3) Under a protective atmosphere, sodium hydroxide solution, ammonia solution and water are added to the reactor to prepare a reaction base solution with a pH of 9.5-11.9 and an ammonia concentration of 0.5-10.0 g / L. Seed filter cake is added to the reactor, and then metal salt solution, sodium hydroxide solution and ammonia solution are introduced. The overflow valve is opened to carry out the reaction. When the particle size grows to 5.0-7.0 μm, the overflow valve is closed and the thickener is started. The reaction continues until the particle size grows to 7.5-9 μm. The flow rate of the metal salt solution is adjusted. When the particle size grows to 9.2-15.0 μm, the material is collected, aged, washed, dried and sieved to obtain a radially porous nickel cobalt manganese hydroxide precursor.

[0043] In the preparation of the precursor, the present invention first co-precipitates a metal salt solution, a sodium hydroxide solution, and an ammonia solution until the particle size grows to 2.5–4.0 μm. Then, the pH is adjusted to 10.7–11.6, and the reaction continues until the particle size stabilizes at 3.5–5.0 μm, resulting in a seed filter cake. The seed filter cake is then added to a reaction vessel and allowed to grow through overflow until the particle size reaches 5.0–7.0 μm. Subsequently, it is concentrated and grown to a particle size of 8.0–15.0 μm, thus preparing the aforementioned primary grains that are thin, interwoven, and radially porous.

[0044] In the preparation process, the present invention can prepare a loose and porous radial fine whisker nickel cobalt manganese hydroxide precursor by using ammonia-free or low-ammonia process conditions, which can effectively reduce the consumption of ammonia water, which is conducive to achieving green, environmentally friendly and safe production and reducing production costs. At the same time, reducing the amount of ammonia water used can reduce wastewater treatment steps and reduce wastewater treatment costs.

[0045] This invention employs a seeding method, in which the ammonia concentration is gradually reduced to 0–0.8 g / L during the overflow growth-concentration growth process. This control of seeding and the gradual decrease in ammonia concentration helps to prepare a radial ternary precursor material with a compact core and a loose and porous outer ring, ensuring ion transport channels, increasing the contact area of ​​the electrolyte, and solving the problem of material cracking during charging and discharging, thereby improving electrochemical performance.

[0046] For example, nickel salts include at least one of nickel sulfate, nickel nitrate, and nickel chloride.

[0047] For example, cobalt salts include at least one of cobalt sulfate, cobalt nitrate, and cobalt chloride.

[0048] For example, manganese salts include at least one of manganese sulfate, manganese nitrate, and manganese chloride.

[0049] It should be noted that those skilled in the art can select specific nickel salts, cobalt salts, and manganese salts according to actual needs, as long as the corresponding nickel, cobalt, and manganese supply effects are achieved.

[0050] In one embodiment, the total metal ion concentration of the metal salt solution is 0.5 to 4 mol / L, preferably 1 to 2.5 mol / L, and more preferably 2 mol / L.

[0051] In one embodiment, the molar concentration of the sodium hydroxide solution is 0.5–14 mol / L, preferably 8–12 mol / L, and more preferably 10 mol / L.

[0052] In one embodiment, the molar concentration of the ammonia solution is 0.5–14 mol / L, preferably 10–14 mol / L, and more preferably 12 mol / L.

[0053] In one embodiment, the flow rate of the metal salt solution in step (2) is 20-60 L / h, the flow rate of the sodium hydroxide solution is 8-25 L / h, and the flow rate of the ammonia solution is 0.5-4 L / h.

[0054] In one embodiment, the flow rate of the metal salt solution in step (3) is 20-60 L / h, the flow rate of the sodium hydroxide solution is 4-15 L / h, and the flow rate of the ammonia solution is 0-0.8 L / h.

[0055] In one embodiment, the flow rate of the metal salt solution in step (3) is adjusted to 40-50 L / h.

[0056] The following embodiments are provided to facilitate understanding of the invention. These embodiments are not intended to limit the scope of the claims.

[0057] Example 1

[0058] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (ammonia-free process) includes the following steps:

[0059] (1) Solution preparation:

[0060] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.93:0.06:0.01 and a total metal concentration of 2 mol / L.

[0061] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0062] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0063] (2) Seed preparation:

[0064] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0065] (3) Precursor growth:

[0066] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a stirring frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the metal salt solution pump and the sodium hydroxide solution pump were turned on at the same time to ensure that the two solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0067] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the agitator is controlled at 28Hz, there is no replenishment of ammonia water, the ammonia concentration gradually becomes 0g / L, the flow rate of the metal salt solution is controlled at 40L / h, the pH value is controlled at 9.6, the metal ions continuously undergo co-precipitation reaction on the seed crystal particles, and the crystals continuously grow. When the seed crystal grows to D50=6.5μm, it enters the concentration growth stage.

[0068] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 9.6, ammonia concentration = 0 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0069] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0070] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0071] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.96 Co 0.06 Mn 0.01 The SEM images and cross-sectional views of the nickel-cobalt-manganese hydroxide precursor powder prepared by (OH)2 are shown below. Figure 1 , Figure 2 As shown, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles that form radially porous secondary particles.

[0072] Example 2

[0073] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (low-ammonia process) includes the following steps:

[0074] (1) Solution preparation:

[0075] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.93:0.06:0.01 and a total metal concentration of 2 mol / L.

[0076] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0077] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0078] (2) Seed preparation:

[0079] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0080] (3) Precursor growth:

[0081] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0082] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 0.5g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 9.9. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0083] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 9.9, ammonia concentration = 0.5 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0084] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0085] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0086] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.96 Co 0.06 Mn 0.01 (OH)2, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radial, loosely porous secondary particles.

[0087] Example 3

[0088] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (low-ammonia process) includes the following steps:

[0089] (1) Solution preparation:

[0090] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.93:0.06:0.01 and a total metal concentration of 2 mol / L.

[0091] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0092] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0093] (2) Seed preparation:

[0094] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0095] (3) Precursor growth:

[0096] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0097] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 0.9g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 10.2. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0098] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 10.2, ammonia concentration = 0.9 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0099] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0100] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0101] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.96 Co 0.06 Mn 0.01 (OH)2, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radial, loosely porous secondary particles.

[0102] Example 4

[0103] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (ammonia-free process) includes the following steps:

[0104] (1) Solution preparation:

[0105] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.94:0.05:0.01 and a total metal concentration of 2 mol / L.

[0106] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0107] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0108] (2) Seed preparation:

[0109] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0110] (3) Precursor growth:

[0111] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a stirring frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the metal salt solution pump and the sodium hydroxide solution pump were turned on at the same time to ensure that the two solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0112] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the agitator is controlled at 28Hz, there is no replenishment of ammonia water, the ammonia concentration gradually becomes 0g / L, the flow rate of the metal salt solution is controlled at 40L / h, the pH value is controlled at 9.6, the metal ions continuously undergo co-precipitation reaction on the seed crystal particles, and the crystals continuously grow. When the seed crystal grows to D50=6.5μm, it enters the concentration growth stage.

[0113] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 9.6, ammonia concentration = 0 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0114] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0115] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0116] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.95 Co 0.04 Mn 0.01 (OH)2, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radial, loosely porous secondary particles.

[0117] Example 5

[0118] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (low-ammonia process) includes the following steps:

[0119] (1) Solution preparation:

[0120] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.94:0.05:0.01 and a total metal concentration of 2 mol / L.

[0121] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0122] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0123] (2) Seed preparation:

[0124] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0125] (3) Precursor growth:

[0126] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0127] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 0.5g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 9.9. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0128] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 9.9, ammonia concentration = 0.5 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0129] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0130] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0131] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.95 Co 0.04 Mn 0.01 (OH)2, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radial, loosely porous secondary particles.

[0132] Example 6

[0133] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (low-ammonia process) includes the following steps:

[0134] (1) Solution preparation:

[0135] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.94:0.05:0.01 and a total metal concentration of 2 mol / L.

[0136] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0137] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0138] (2) Seed preparation:

[0139] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0140] (3) Precursor growth:

[0141] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0142] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 0.9g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 10.2. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0143] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 10.2, ammonia concentration = 0.9 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0144] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0145] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0146] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.95 Co 0.04 Mn 0.01 (OH)2, the nickel-cobalt-manganese hydroxide precursor has thin primary grains with interlaced primary particles forming radial, loosely porous secondary particles.

[0147] Comparative Example 1

[0148] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (high-ammonia process, only the ammonia concentration differs from Example 1) includes the following steps:

[0149] (1) Solution preparation:

[0150] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.93:0.06:0.01 and a total metal concentration of 2 mol / L.

[0151] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0152] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0153] (2) Seed preparation:

[0154] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0155] (3) Precursor growth:

[0156] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0157] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 5.0g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 11.0. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0158] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 11.0, ammonia concentration = 5.0 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0159] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0160] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0161] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.96 Co 0.06 Mn 0.01 The SEM images and cross-sectional views of the nickel-cobalt-manganese hydroxide precursor powder prepared by (OH)2 are shown below. Figure 3 , Figure 4 As shown, the interior of Comparative Example 1 is dense with few or no pores, which ultimately results in a small specific surface area for the comparative example product.

[0162] Comparative Example 2

[0163] A method for preparing a radially porous nickel-cobalt-manganese hydroxide precursor (high-ammonia process) includes the following steps:

[0164] (1) Solution preparation:

[0165] Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water and mixed evenly to prepare a ternary metal salt solution with a molar ratio of nickel, cobalt, and manganese of 0.94:0.05:0.01 and a total metal concentration of 2 mol / L.

[0166] Prepare a sodium hydroxide solution with a molar concentration of 10 mol / L;

[0167] Prepare an ammonia solution with a molar concentration of 12 mol / L;

[0168] (2) Seed preparation:

[0169] Open the nitrogen valve of the reactor and simultaneously introduce nitrogen and pure water into the reactor until the liquid level reaches the pH meter probe inside the reactor. Turn on the heating equipment to raise the temperature inside the reactor to 65℃. Adjust the stirring frequency of the agitator to 30Hz. Add appropriate amounts of sodium hydroxide solution and ammonia solution to the reactor to maintain the pH value of the bottom liquid at 11.4 and the ammonia concentration at 2.0g / L, thus obtaining the reaction bottom liquid. Turn on the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump to allow the metal... Salt solution, sodium hydroxide solution, and ammonia solution are continuously fed into the reactor at flow rates of 30 L / h, 12 L / h, and 0.5 L / h, respectively, to carry out a co-precipitation reaction. When the particle size grows to 4.0 μm, the pH is adjusted to 11.6 to generate new spherical particles, thereby ensuring that the particle size of the secondary spherical particles in the reactor is maintained at about 4.0 to 4.5 μm. After the particle size is stabilized, seed crystals are collected. The collected material is centrifuged, washed, and dehydrated to obtain a seed crystal filter cake.

[0170] (3) Precursor growth:

[0171] The reaction was carried out in an intermittent manner with nitrogen protection throughout. Pure water was injected into the reactor up to the pH probe level, and the stirring was started and kept at a frequency of 28 Hz. The heating equipment was turned on to maintain the temperature inside the reactor at 65 ℃. Then, 130 kg of seed filter cake was added to the reactor. Immediately afterwards, a certain amount of sodium hydroxide solution and ammonia solution were added to the reactor to make the initial pH value reach 10.6 and the ammonia concentration reach 0.9 g / L. After all the start-up conditions were prepared, the switches of the metal salt solution pump, sodium hydroxide solution pump, and ammonia solution pump were turned on at the same time to ensure that the three solutions were mixed evenly under continuous stirring and to generate a uniform hydroxide precipitate.

[0172] Overflow growth: The overflow switch of the reactor is always open, the temperature inside the reactor is controlled at 65℃, the frequency of the stirring paddle is controlled at 28Hz, the ammonia concentration is controlled at 5.0g / L, the flow rate of the metal salt solution is controlled at 40L / h, and the pH value is controlled at 11.0. Metal ions continuously undergo co-precipitation reactions on the seed crystals, and the crystals continue to grow. When the seed crystals grow to D50 = 6.5μm, they enter the concentration growth stage.

[0173] Concentration and growth: First, turn off the overflow switch and reduce the stirring frequency to 26 Hz. Keep the temperature, ammonia concentration, pH value, and metal salt solution flow rate in the reactor unchanged in the early stage (i.e., temperature = 65℃, pH = 11.0, ammonia concentration = 5 g / L). When the median particle size D50 of the crystals reaches 9.0 μm, adjust the stirring frequency to 23 Hz and the metal salt solution flow rate to 45 L / h. Keep the temperature, ammonia concentration, and pH value unchanged to ensure that the crystals grow according to the design requirements. When the median particle size D50 of the quasi-spherical secondary particles grows to 9.8-10.0 μm, remeasure the particle size. If the design requirements are met, stop the liquid feeding and end the experiment.

[0174] (4) Aging: Transfer the material after the reaction is completed to the aging tank, turn on the stirring at 23 Hz, and age for 12 hours.

[0175] (5) Washing, drying and sieving stage: After the material has finished aging, it is washed with alkali and water and then spun dry in a centrifuge to obtain filter cake. The filter cake is then dried in an oven at 100-150℃ and finally sieved to obtain nickel cobalt manganese hydroxide precursor powder.

[0176] The chemical formula of the prepared nickel-cobalt-manganese hydroxide precursor powder is Ni 0.95 Co 0.04 Mn 0.01 (OH)2, the interior of Comparative Example 2 is dense with few or no pores, which ultimately results in a small specific surface area of ​​the comparative example product.

[0177] Test case

[0178] The properties of the nickel-cobalt-manganese hydroxide precursors described in Examples 1-6 and Comparative Examples 1-2 are shown in Table 1.

[0179] Table 1

[0180]

[0181] This invention uses a low-ammonia or ammonia-free process to prepare secondary particles with fine and thin primary grains that are interwoven and interconnected, forming a radial, loose, and porous internal structure. In contrast, comparative examples 1 and 2, due to a high-ammonia process, have dense, low-pore, or even non-pore internal structures, resulting in a smaller specific surface area for the comparative product.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A nickel-cobalt-manganese hydroxide precursor with a radially porous structure, characterized in that, The chemical formula of the nickel-cobalt-manganese hydroxide precursor is Ni x Co y Mn 1-x-y (OH)2, where 0.5≤x≤1, 0≤y≤0.4; The nickel-cobalt-manganese hydroxide precursor has thin primary grains that are interwoven to form radially porous secondary particles with a specific surface area of ​​20–30 m². 2 / g, The method for preparing the radially porous nickel-cobalt-manganese hydroxide precursor includes the following steps: (1) Prepare metal salt solutions by mixing nickel salt, cobalt salt and manganese salt with water according to the molar ratio of nickel, cobalt and manganese elements in the nickel cobalt manganese hydroxide precursor. (2) Under a protective atmosphere, sodium hydroxide solution, ammonia solution and water are added to the reaction vessel to prepare a reaction base solution with a pH of 9.5 to 11.9 and an ammonia concentration of 0.5 to 10.0 g / L. Metal salt solution, sodium hydroxide solution and ammonia solution are introduced into the reaction vessel to carry out a co-precipitation reaction. When the particle size grows to 2.5 to 4.0 μm, the pH is adjusted to 10.7 to 11.6 and the reaction continues until the particle size is stable at 3.5 to 5.0 μm. The material is collected, centrifuged and dehydrated to obtain a seed filter cake. (3) Under a protective atmosphere, sodium hydroxide solution, ammonia solution and water are added to the reactor to prepare a reaction base solution with a pH of 9.5 to 11.9 and an ammonia concentration of 0.5 to 10.0 g / L. Seed filter cake is added to the reactor, and then metal salt solution, sodium hydroxide solution and ammonia solution are introduced. The overflow valve is opened to carry out the reaction. When the particle size grows to 5.0 to 7.0 μm, the overflow valve is closed and the thickener is started. The reaction continues until the particle size grows to 7.5 to 9 μm. The flow rate of the metal salt solution is adjusted. When the particle size grows to 9.2 to 15.0 μm, the material is collected. After aging, washing, drying and sieving, a radially porous nickel cobalt manganese hydroxide precursor is obtained.

2. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, The nickel-cobalt-manganese hydroxide precursor has a microstructure of spherical particles and a tap density of 1.5–2.5 g / cm³. 3 Particle size distribution diameter ≤ 1.

0.

3. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 2, characterized in that, The nickel-cobalt-manganese hydroxide precursor has a microstructure of spherical particles and a tap density of 1.6–2 g / cm³. 3 The particle size distribution has a diameter of ≤0.

7.

4. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, The nickel salt includes at least one of nickel sulfate, nickel nitrate, and nickel chloride; and / or The cobalt salt includes at least one of cobalt sulfate, cobalt nitrate, and cobalt chloride; and / or The manganese salt includes at least one of manganese sulfate, manganese nitrate, and manganese chloride.

5. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, The total metal ion concentration of the metal salt solution is 0.5–4 mol / L.

6. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, The molar concentration of the sodium hydroxide solution is 0.5–14 mol / L, and the molar concentration of the ammonia solution is 0.5–14 mol / L.

7. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, In step (2), the flow rate of the metal salt solution is 20-60 L / h, the flow rate of the sodium hydroxide solution is 8-25 L / h, and the flow rate of the ammonia solution is 0.5-4 L / h.

8. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, In step (3), the flow rate of the metal salt solution is 20-60 L / h, the flow rate of the sodium hydroxide solution is 4-15 L / h, and the flow rate of the ammonia solution is 0-0.8 L / h.

9. The radially porous nickel-cobalt-manganese hydroxide precursor according to claim 1, characterized in that, In step (3), the flow rate of the metal salt solution is adjusted to 40-50 L / h.

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