High-nickel large-particle precursor as well as preparation method and application thereof

Abstract

The invention discloses a high-nickel large-particle precursor as well as a preparation method and application thereof, and belongs to the technical field of battery materials. The preparation method of the precursor comprises the following steps: adding a metal salt solution, a precipitator solution and a complexing agent solution into a first reaction container with a base solution in a parallel flow manner, and carrying out a first co-precipitation reaction under a stirring condition until a preset particle size is reached, so as to obtain first slurry; transferring the first slurry into a second reaction container, simultaneously adding a metal salt solution, a precipitator solution, an additive solution and a complexing agent solution in a parallel flow manner, and carrying out a second coprecipitation reaction under a stirring condition to obtain second slurry; and concentrating the second slurry until the material grows to the target particle size, and aging. The preparation method is simple, can produce the high-nickel ternary large-particle precursor with high secondary particle sphericity degree, relatively wide distribution and mixed large and small particles, and is beneficial to solving the hidden dangers of the high-nickel ternary lithium battery in the aspects of performance and safety caused by secondary particle cracking of the high-nickel ternary precursor.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and in particular to a high-nickel large-particle precursor and a preparation method and application thereof. Background Art

[0002] As the application of lithium-ion batteries in the field of new energy is gradually expanding, terminals such as automobiles, ships, airplanes, and mobile electronic devices have put forward higher requirements for lithium batteries, such as long battery life, long life, and high safety. For ternary lithium batteries, high-nickel ternary lithium batteries are currently the power batteries that the new energy industry is focusing on due to their large capacity, high power, and high energy density. Nickel 8 series and 9 series are very popular in the market. Ternary lithium batteries are sintered from ternary precursors. 80% of the characteristics of ternary positive electrode materials come from the influence of the inherent characteristics of the ternary precursors themselves, so the performance of ternary precursors seriously affects the performance of lithium batteries. However, while further improving the capacity, nickel 8 series and 9 series ultra-high nickel precursors face a technical difficulty in the preparation of large-particle precursors. When the particle size of the precursor grows to more than 10μm, the secondary particle ball cracks due to uneven stress in the precursor, which ultimately leads to poor cycle performance and low safety of lithium batteries.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a high-nickel large-particle precursor and a preparation method and application thereof, so as to solve or improve the above-mentioned technical problems.

[0005] The present invention can be implemented like this:

[0006] In the first aspect, the present invention provides a method for preparing a high-nickel large-particle precursor, wherein the chemical formula of the high-nickel large-particle precursor is Ni x Co y Mn z (OH)2, where x+y+z=1, 0.8≤x<1, 0 <y<0.2,0<z<0.2;

[0007] The preparation of high nickel large particle precursor includes the following steps:

[0008] A metal salt solution, a precipitant solution and a complexing agent solution are added to a first reaction container having a base solution in parallel, and a first coprecipitation reaction is carried out under stirring until an inner core is generated and grows to D 50 The first slurry containing nickel, cobalt and manganese hydroxide is 5 μm to 8 μm, wherein the reaction temperature of the first coprecipitation reaction is 50° C. to 65° C., the ammonia value is controlled to be 6 g / L to 9 g / L, the pH value is adjusted to 11.7 to 11.9 after 2 hours of reaction, and the pH value is adjusted to 11.3 to 11.6 after 10 hours of reaction;

[0009] The first slurry is transferred to a second reaction container, and a metal salt solution, a precipitant solution, an additive solution and a complexing agent solution are added simultaneously in a parallel flow manner, and a second coprecipitation reaction is carried out under stirring conditions to obtain a second slurry; wherein the reaction temperature of the second coprecipitation reaction is 50° C. to 65° C., the ammonia value is controlled to be 4 g / L to 12 g / L, and the reaction pH value is controlled to be 11.3 to 11.6;

[0010] The second slurry is concentrated until the material reaches D 50 10μm~15μm;

[0011] Will grow to D 50 The material with a size of 10 μm to 15 μm is aged, wherein the aging is carried out at 55° C. to 70° C. and a pH of 11.9 to 12.2 for 4 h to 10 h.

[0012] In an optional embodiment, the metal salt solution is a mixed solution containing nickel salt, cobalt salt and manganese salt; the total concentration of metal ions in the metal salt solution is 1 mol / L to 3 mol / L, and the molar ratio of Ni, Co and Mn is x:y:z.

[0013] In an optional embodiment, the form of the metal salt in the metal salt solution includes at least one of sulfate, nitrate and halogen salt.

[0014] In an alternative embodiment, the additive in the additive solution is an organic compound surfactant.

[0015] In an alternative embodiment, the additive includes sodium lauryl sulfate.

[0016] In an optional embodiment, the concentration of the additive solution is 0.8 mol / L to 1.5 mol / L.

[0017] In an alternative embodiment, the molar ratio of the additive in the additive solution to the metal salt in the metal salt solution is 0.06:1 to 0.13:1.

[0018] In an optional embodiment, the precipitant solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 4 mol / L to 12 mol / L.

[0019] In an optional embodiment, the complexing agent solution is aqueous ammonia or an ammonium salt solution with a concentration of 4 g / L to 12 g / L.

[0020] In an alternative embodiment, the ammonium salt solution comprises ammonium sulfate solution.

[0021] In an optional embodiment, the mass fraction of aqueous ammonia is 18% to 23%.

[0022] In an optional embodiment, the flow rate of the metal salt solution is 40 mL / min to 80 mL / min.

[0023] In an optional embodiment, the stirring speed is 300 rpm to 900 rpm.

[0024] In a second aspect, the present invention provides a high-nickel large-particle precursor, which is prepared by the preparation method of any one of the aforementioned embodiments.

[0025] In a third aspect, the present invention provides a positive electrode material, the precursor of which is the high-nickel large-particle precursor of the aforementioned embodiment.

[0026] In a fourth aspect, the present invention provides a battery, wherein raw materials for preparing the battery include the positive electrode material of the aforementioned embodiment.

[0027] The beneficial effects of the present invention include:

[0028] The preparation method of the high-nickel large-particle precursor provided by the present invention not only solves the problem of easy cracking of the high-nickel large-particle precursor product by combining step-by-step co-precipitation, the use of additives and aging under specific conditions, but also realizes the mixing of large and small particles at the precursor reaction end, reducing the mixing of large and small particles of the rear-end precursor or the mixing of large and small particles at the positive electrode material end. The preparation method is simple to operate, has strong economies of scale, and is conducive to industrial production. The secondary particles of the prepared high-nickel ternary large-particle precursor have good sphericity, relatively wide distribution, and contain large particles and small particles at the same time, which is conducive to improving the cycle performance and safety performance of downstream battery products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is a SEM image of the high-nickel large particle precursor prepared in Example 1;

[0031] Figure 2 This is a SEM image of the high-nickel large particle precursor prepared in Example 2;

[0032] Figure 3 This is a SEM image of the high-nickel large particle precursor prepared in Example 3;

[0033] Figure 4 This is a SEM image of the high-nickel large particle precursor prepared in Example 4;

[0034] Figure 5 This is a SEM image of the high-nickel large particle precursor prepared in Comparative Example 1;

[0035] Figure 6 This is a SEM image of the high-nickel large particle precursor prepared in Comparative Example 2;

[0036] Figure 7 This is a SEM image of the high-nickel large particle precursor prepared in Comparative Example 3;

[0037] Figure 8 This is a SEM image of the high-nickel large particle precursor prepared in Comparative Example 4;

[0038] Fig. 9 This is the SEM image of the high-nickel large-particle precursor prepared in Comparative Example 5. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0040] The high-nickel large-particle precursor provided by the present invention and its preparation method and application are specifically described below.

[0041] The present invention provides a method for preparing a high-nickel large-particle precursor. The chemical formula of the high-nickel large-particle precursor is Ni x Co y Mn z (OH)2, where x+y+z=1, 0.8≤x<1, 0 <y<0.2,0<z<0.2。

[0042] The solutions involved in the preparation process of the high nickel large particle precursor are as follows:

[0043] Metal salt solution: The metal salt solution is a mixed solution containing nickel salt, cobalt salt and manganese salt. The total concentration of metal ions in the metal salt solution is 1 mol / L to 3 mol / L, such as 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, etc., and can also be other values ​​within the range of 1 mol / L to 3 mol / L. The molar ratio of Ni, Co and Mn in the metal salt solution is x:y:z, which is consistent with the general chemical formula. The form of the metal salt in the metal salt solution can illustratively include at least one of sulfate, nitrate and halogen salt.

[0044] Precipitant solution: The precipitant solution can be a sodium hydroxide solution or a potassium hydroxide solution. The concentration of the precipitant solution can be 4mol / L to 12mol / L, such as 4mol / L, 6mol / L, 8mol / L, 10mol / L or 12mol / L, etc., or other values ​​within the range of 4mol / L to 12mol / L.

[0045] Complexing agent solution: The complexing agent solution can be ammonia water or an ammonium salt solution. The concentration of the complexing agent solution can be 4g / L to 12g / L, such as 4g / L, 6g / L, 8g / L, 10g / L or 12g / L, etc., or other values ​​within the range of 4g / L to 12g / L. The ammonium salt solution can exemplarily include ammonium sulfate solution, etc. The mass fraction of ammonia water can be 18% to 23%, such as 18%, 19%, 20%, 21%, 22% or 23%, etc., or other values ​​within the range of 18% to 23%.

[0046] Additive solution: The additive in the additive solution is an organic compound surfactant, for example, sodium dodecyl sulfate, etc. The concentration of the additive solution can be 0.8 mol / L to 1.5 mol / L, such as 0.8 mol / L, 1.0 mol / L, 1.2 mol / L or 1.5 mol / L, etc., and can also be other values ​​within the range of 0.8 mol / L to 1.5 mol / L.

[0047] Base solution: obtained by mixing pure water, the above-mentioned precipitant solution and the above-mentioned complexing agent solution, wherein the amount of the precipitant solution is used to adjust the pH value of the base solution to 11.8-11.9, and the amount of the complexing agent solution is used to adjust the ammonia value of the base solution to 4g / L-12g / L.

[0048] Specifically, under the protection of inert gas, pure water, precipitant solution, and complexing agent solution are added into the reaction kettle, and the mixture is stirred (stirring speed is 300 rpm to 900 rpm) and kept at a constant temperature (50° C. to 65° C.) to prepare the reaction kettle bottom liquid.

[0049] The preparation of the high nickel large particle precursor comprises the following steps:

[0050] S1: Add metal salt solution, precipitant solution and complexing agent solution in parallel to the first reaction container with the base solution, and perform the first coprecipitation reaction under stirring until the inner core is generated and grows to D 50 The diameter of the nickel-cobalt-manganese hydroxide is 5 μm to 8 μm (such as 5 μm, 6 μm, 7 μm or 8 μm, etc.), and a first slurry containing nickel, cobalt and manganese hydroxide is obtained.

[0051] The stirring speed of the first coprecipitation reaction is 300 rpm to 900 rpm, such as 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm, and may also be other values ​​within the range of 300 rpm to 900 rpm.

[0052] The reaction temperature of the first coprecipitation reaction is 50°C to 65°C, such as 50°C, 52°C, 55°C, 58°C, 60°C, 62°C or 65°C, etc., and can also be other values ​​within the range of 50°C to 65°C.

[0053] The flow rate of the metal salt solution can be 40 mL / min to 80 mL / min, such as 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min or 80 mL / min, or other values ​​within the range of 40 mL / min to 80 mL / min.

[0054] The ammonia value is controlled by the flow rate of the complexing agent solution to be 6g / L to 9g / L, such as 6g / L, 7g / L, 8g / L or 9g / L, etc. It can also be other values ​​within the range of 6g / L to 9g / L.

[0055] After 2 hours of reaction, the reaction pH value is adjusted to 11.7-11.9 (such as 11.7, 11.8 or 11.9, etc.) by adjusting the flow rate of the precipitant. After 10 hours of reaction, the reaction pH value is adjusted to 11.3-11.6 (such as 11.3, 11.4, 11.5 or 11.6, etc.) by adjusting the flow rate of the precipitant.

[0056] The above processes are all carried out under the protection of inert gas, with material being fed and discharged at the same time.

[0057] S2: Transfer the first slurry to a second reaction container, add a metal salt solution, a precipitant solution, an additive solution and a complexing agent solution simultaneously in a parallel flow manner, and carry out a second co-precipitation reaction under stirring conditions to obtain a second slurry; wherein, the reaction temperature of the second co-precipitation reaction is 50°C to 65°C, the ammonia value is controlled to be 4g / L to 12g / L, and the reaction pH value is controlled to be 11.3 to 11.6.

[0058] The above processes are all carried out under the protection of inert gas, with material being fed and discharged at the same time.

[0059] After the first slurry is transferred to the second reaction container, the liquid level is controlled at about 2 / 3 of the effective volume of the second reaction container.

[0060] The stirring speed of the second coprecipitation reaction is 300 rpm to 900 rpm, such as 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm, etc., and can also be other values ​​within the range of 300 rpm to 900 rpm.

[0061] The reaction temperature of the second coprecipitation reaction is 50°C to 65°C, such as 50°C, 52°C, 55°C, 58°C, 60°C, 62°C or 65°C, etc., and can also be other values ​​within the range of 50°C to 65°C.

[0062] The flow rate of the metal salt solution can be 40 mL / min to 80 mL / min, such as 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min or 80 mL / min, or other values ​​within the range of 40 mL / min to 80 mL / min.

[0063] The ammonia value is controlled by the flow rate of the complexing agent solution to be 4g / L to 12g / L, such as 4g / L, 6g / L, 8g / L, 10g / L or 12g / L, etc. It can also be other values ​​within the range of 4g / L to 12g / L.

[0064] The reaction pH is adjusted to 11.3-11.6 (such as 11.3, 11.4, 11.5 or 11.6, etc.) by adjusting the flow rate of the precipitant.

[0065] The molar ratio of the additive in the additive solution to the metal salt in the metal salt solution is 0.06:1 to 0.13:1, such as 0.06:1, 0.08:1, 0.1:1 or 0.13:1, etc., and can also be other values ​​within the range of 0.06:1 to 0.13:1.

[0066] By adding surfactants in the above proportion, it is beneficial to selective precipitation of crystals, reducing the occupancy and structural changes caused by crystal defects, and at the same time, it can also improve the crystallinity, thereby reducing the risk of ball cracking.

[0067] If the amount of additives used is too little, it is difficult to achieve the effect of reducing ball cracking; if the amount of additives used is too much, it is easy to cause the secondary ball particles to fail to agglomerate into balls, and the physical and chemical indicators of the product such as specific surface area and tap density are out of control.

[0068] S3: Concentrate the second slurry until the material reaches D 50 It is 10μm to 15μm (such as 10μm, 11μm, 12μm, 13μm, 14μm or 15μm, etc.).

[0069] When the liquid level in the reactor reaches the overflow port, it enters the thickener for concentration and the clear liquid is discharged.

[0070] S4: will grow to D 50 The aging is carried out at 55°C to 70°C and pH 11.9 to 12.2 for 4 hours to 10 hours.

[0071] Specifically, it will grow to D 50 The material with a size of 10 μm to 15 μm is pumped into the aging tank for aging.

[0072] The aging temperature may be 55°C, 60°C, 65°C or 70°C, etc., or other values ​​within the range of 55°C to 70°C.

[0073] The pH value of aging can be 11.9, 12.0, 12.1 or 12.2, etc., or other values ​​within the range of 11.9 to 12.2.

[0074] If the pH value of aging is lower than 11.9, it is not conducive to the re-precipitation of free metal ions to repair the surface of secondary particles; if the pH value of aging is higher than 12.2, it is not conducive to the washing of product impurity sulfur.

[0075] The aging time can be 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc., or other values ​​within the range of 4h to 10h.

[0076] It should be noted that under certain temperature, pH and stirring conditions, the unreacted metal ions in the mother liquor gradually reach equilibrium through the solute and solvent in the aging slurry, making the components of the precursor more uniform, reducing the stress inside the particles, and thus improving the density and uniformity of the material. In addition, aging can also improve the crystal structure of the precursor and make it more perfect.

[0077] S5: The aged material is pumped into a solid-liquid separation device for washing. After the sodium sulfur is qualified, the filter cake is sent to a drying device for drying to a moisture content of ≤0.3%. After iron removal and screening, the precursor product is obtained.

[0078] In line with the above, the preparation method of the high-nickel large-particle precursor provided by the present invention can not only solve the problem of easy cracking of the high-nickel large-particle precursor product, but also realize the mixing of large and small particles at the precursor reaction end, thereby reducing the mixing of large and small particles of the rear-end precursor or the mixing of large and small particles at the positive electrode material end. The preparation method is simple to operate, has strong economies of scale, and is conducive to industrial production.

[0079] Correspondingly, the present invention also provides a high-nickel large-particle precursor, which is prepared by the above preparation method.

[0080] The particle size of the high-nickel large-particle precursor is 10 μm to 15 μm, the secondary particles have good sphericity, are relatively widely distributed, and are mixed with large particles and small particles.

[0081] In addition, the present invention also provides a positive electrode material, the precursor of which is the above-mentioned high-nickel large-particle precursor.

[0082] Furthermore, the present invention also provides a battery, the raw materials for preparing the battery include the above-mentioned positive electrode material.

[0083] The battery can have better cycle performance and safety performance.

[0084] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0085] Example 1

[0086] This embodiment provides a high-nickel large-particle precursor, and the preparation method thereof includes:

[0087] (1) Preparation of raw and auxiliary materials: Add nickel sulfate, cobalt sulfate and manganese sulfate crystals in a molar ratio of Ni, Co and Mn of 80:10:10, stir and dissolve in pure water to prepare a mixed metal salt solution with a total metal concentration of 1.8 mol / L; at the same time, prepare a sodium hydroxide solution with a concentration of 11 mol / L as a precipitant solution; an ammonia solution with a concentration of 8 g / L as a complexing agent solution; and a sodium dodecyl sulfate solution with a concentration of 1 mol / L as an additive solution.

[0088] (2) First coprecipitation reaction: pure water was added to the reactor to the overflow port, the reactor was heated to 60°C to maintain a constant temperature, and then the precipitant solution was added to adjust the pH value to 11.8-11.9, and then the complexing agent solution was added to adjust the ammonia value to 8 g / L. The mixed metal salt solution was pumped into the reactor together with the precipitant solution and the complexing agent solution at a flow rate of 60 mL / min, and the flow rate of the complexing agent solution was adjusted to control the ammonia value to 8 g / L. After two hours of reaction, the precipitant flow rate was adjusted to control the pH value to 11.7-11.8. After 10 hours of reaction, the precipitant flow rate was adjusted to control the pH value to 11.3-11.4. The stirring speed was maintained at 700 rpm, and the material was stirred under the protection of inert gas until the particle size D 50 The particle size D of the reactor material is stably controlled. 50 8μm.

[0089] (3) Second coprecipitation reaction: Pump the slurry obtained from the first coprecipitation reaction into another reactor, control the liquid level at 2 / 3 of the effective volume, keep the reactor temperature at 60°C, and stir at 400rpm. Under the protection of inert gas, introduce the precipitant solution, complexing agent solution, and additive solution at the same time, wherein the molar ratio of the additive solution is 1:0.06, and the flow rate of the precipitant solution is adjusted to control the reaction pH value to 11.3-1.4, and the flow rate of the complexing agent solution is adjusted to control the ammonia value to 10g / L. Until the reactor liquid level reaches the overflow port, enters the thickener, and discharges the clear liquid. Maintain the above reaction conditions until the particle size grows to the target particle size D 50 is 12μm.

[0090] (4) Grow the particle size to D 50 The material with a particle size of 12 μm is pumped into the aging tank and aged for 8 hours at 55°C and pH 11.9. After the aging is completed, the material is pumped into the solid-liquid separation equipment for washing. After the sodium sulfur is qualified, the filter cake is sent to the drying equipment and dried to a moisture content of ≤0.3%. After iron removal, screening and packaging, a high-nickel large-particle precursor Ni 0.9 Co 0.02 Mn 0.08 (OH)2.

[0091] Example 2

[0092] This embodiment provides a high-nickel large-particle precursor, and the preparation method thereof includes:

[0093] (1) Preparation of raw and auxiliary materials: Add nickel sulfate, cobalt sulfate and manganese sulfate crystals in a molar ratio of Ni, Co and Mn of 90:2:8, stir and dissolve in pure water to prepare a mixed metal salt solution with a total metal concentration of 1.8 mol / L; at the same time, prepare a sodium hydroxide solution with a concentration of 11 mol / L as a precipitant solution; an ammonia solution with a concentration of 8 g / L as a complexing agent solution; and a sodium dodecyl sulfate solution with a concentration of 1 mol / L as an additive solution.

[0094] (2) First coprecipitation reaction: Add pure water to the reactor to the overflow port, heat the reactor to 60°C and keep the temperature constant, then add the precipitant solution to adjust the pH value to 12-12.1, and then add the complexing agent solution to adjust the ammonia value to 8g / L. Pump the mixed metal salt solution into the reactor together with the precipitant solution and the complexing agent solution at a flow rate of 60mL / min, adjust the flow rate of the complexing agent solution to control the ammonia value to 8g / L, and after two hours of reaction, adjust the precipitant flow rate to control the pH value to 11.8-11.9. After 10 hours of reaction, adjust the precipitant flow rate to control the pH value to 11.5-11.6. Maintain the stirring speed at 700rpm, and stir under the protection of inert gas until the material grows to a particle size D 50The particle size D of the reactor material is stably controlled. 50 is 6μm.

[0095] (3) Second coprecipitation reaction: Pump the slurry obtained from the first coprecipitation reaction into another reactor, control the liquid level at 2 / 3 of the effective volume, keep the reactor temperature at 60°C, and stir at 400rpm. Under the protection of inert gas, introduce the precipitant solution, complexing agent solution, and additive solution at the same time, wherein the molar ratio of the additive solution is 1:0.08, and adjust the flow rate of the precipitant solution to control the reaction pH value to 11.3-1.4, and adjust the flow rate of the complexing agent solution to control the ammonia value to 10g / L. Until the reactor liquid level reaches the overflow port, enters the thickener, and discharges the clear liquid. Maintain the above reaction conditions until the particle size grows to the target particle size D 50 is 12μm.

[0096] (4) Grow the particle size to D 50 The material with a particle size of 12 μm is pumped into the aging tank and aged for 8 hours at 60°C and pH 12.0. After the aging is completed, the material is pumped into the solid-liquid separation equipment for washing. After the sodium sulfur is qualified, the filter cake is sent to the drying equipment and dried to a moisture content of ≤0.3%. After iron removal, screening and packaging, a high-nickel large-particle precursor Ni 0.8 Co 0.1 Mn 0.1 (OH)2.

[0097] Example 3

[0098] This embodiment provides a high-nickel large-particle precursor, and the preparation method thereof includes:

[0099] (1) Preparation of raw and auxiliary materials: Add nickel sulfate, cobalt sulfate and manganese sulfate crystals in a molar ratio of Ni, Co and Mn of 80:10:10, stir and dissolve in pure water to prepare a mixed metal salt solution with a total metal concentration of 1 mol / L; at the same time, prepare a potassium hydroxide solution with a concentration of 4 mol / L as a precipitant solution; an ammonium sulfate solution with a concentration of 4 g / L as a complexing agent solution; and a sodium dodecyl sulfate solution with a concentration of 0.8 mol / L as an additive solution.

[0100] (2) First coprecipitation reaction: Add pure water to the reactor to the overflow port, heat the reactor to 50°C and keep the temperature constant, then add the precipitant solution to adjust the pH value to 11.8-11.9, then add the complexing agent solution to adjust the ammonia value to 6 g / L. Pump the mixed metal salt solution into the reactor together with the precipitant solution and the complexing agent solution at a flow rate of 40 mL / min, adjust the flow rate of the complexing agent solution to control the ammonia value to 6 g / L, and after two hours of reaction, adjust the precipitant flow rate to control the pH value to 11.7-11.8. After 10 hours of reaction, adjust the precipitant flow rate to control the pH value to 11.3-11.4. Maintain the stirring speed at 300 rpm, and stir under the protection of inert gas until the material grows to a particle size D 50 The particle size D of the reactor material is stably controlled. 50 5μm.

[0101] (3) Second coprecipitation reaction: Pump the slurry obtained from the first coprecipitation reaction into another reactor, control the liquid level at 2 / 3 of the effective volume, keep the reactor temperature at 50°C, and stir at 300rpm. Under the protection of inert gas, introduce the precipitant solution, complexing agent solution, and additive solution at the same time, wherein the molar ratio of the additive solution is 1:0.1, and the flow rate of the precipitant solution is adjusted to control the reaction pH value to 11.3-1.4, and the flow rate of the complexing agent solution is adjusted to control the ammonia value to 9g / L. Until the reactor liquid level reaches the overflow port, enters the thickener, and discharges the clear liquid. Maintain the above reaction conditions until the particle size grows to the target particle size D 50 is 10μm.

[0102] (4) Grow the particle size to D 50 The material with a particle size of 10 μm is pumped into the aging tank and aged for 4 hours at 65°C and pH 12.1. After the aging is completed, the material is pumped into the solid-liquid separation equipment for washing. After the sodium sulfur is qualified, the filter cake is sent to the drying equipment and dried to a moisture content of ≤0.3%. After iron removal, screening and packaging, a high-nickel large-particle precursor Ni 0.9 Co 0.02 Mn 0.08 (OH)2.

[0103] Example 4

[0104] This embodiment provides a high-nickel large-particle precursor, and the preparation method thereof includes:

[0105] (1) Preparation of raw and auxiliary materials: Add nickel sulfate, cobalt sulfate and manganese sulfate crystals in a molar ratio of Ni, Co and Mn of 80:10:10, stir and dissolve in pure water to prepare a mixed metal salt solution with a total metal concentration of 3 mol / L; at the same time, prepare a sodium hydroxide solution with a concentration of 8 mol / L as a precipitant solution; ammonia water with a concentration of 12 g / L as a complexing agent solution; and a sodium dodecyl sulfate solution with a concentration of 1.5 mol / L as an additive solution.

[0106] (2) First coprecipitation reaction: Add pure water to the reactor to the overflow port, heat the reactor to 65°C and keep the temperature constant, then add the precipitant solution to adjust the pH value to 11.8-11.9, then add the complexing agent solution to adjust the ammonia value to 9g / L. Pump the mixed metal salt solution into the reactor together with the precipitant solution and the complexing agent solution at a flow rate of 80mL / min, adjust the flow rate of the complexing agent solution to control the ammonia value to 9g / L, and after two hours of reaction, adjust the precipitant flow rate to control the pH value to 11.7-11.8. After 10 hours of reaction, adjust the precipitant flow rate to control the pH value to 11.3-11.4. Maintain the stirring speed at 900rpm, and stir under the protection of inert gas until the material grows to a particle size D 50 The particle size D of the reactor material is stably controlled. 50 8μm.

[0107] (3) Second coprecipitation reaction: Pump the slurry obtained from the first coprecipitation reaction into another reactor, control the liquid level at 2 / 3 of the effective volume, keep the reactor temperature at 65°C, and stir at 900rpm. Under the protection of inert gas, introduce the precipitant solution, complexing agent solution, and additive solution at the same time, wherein the molar ratio of the additive solution is 1:0.13, and adjust the flow rate of the precipitant solution to control the reaction pH value to 11.3-1.4, and adjust the flow rate of the complexing agent solution to control the ammonia value to 12g / L. Until the reactor liquid level reaches the overflow port, enters the thickener, and discharges the clear liquid. Maintain the above reaction conditions until the particle size grows to the target particle size D 50 is 15μm.

[0108] (4) Grow the particle size to D 50 The material with a particle size of 15 μm is pumped into the aging tank and aged for 10 hours at 70°C and pH 12.2. After the aging is completed, the material is pumped into the solid-liquid separation equipment for washing. After the sodium sulfur is qualified, the filter cake is sent to the drying equipment and dried to a moisture content of ≤0.3%. After iron removal, screening and packaging, a high-nickel large-particle precursor Ni 0.9 Co 0.02 Mn 0.08 (OH)2.

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 1 is that no additive solution is added during the second precipitation reaction.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 1 is that: no aging is performed, and the material obtained by the second precipitation reaction is directly pumped into a solid-liquid separation device for washing. After the sodium sulfur is qualified, the filter cake is sent to a drying device and dried to a moisture content of ≤0.3%, and then iron removal, screening, and packaging are performed.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is that the molar ratio of the additive in the additive solution to the metal salt in the metal salt solution is 0.02:1.

[0115] Comparative Example 4

[0116] The difference between this comparative example and Example 1 is that the molar ratio of the additive in the additive solution to the metal salt in the metal salt solution is 0.5:1.

[0117] Comparative Example 5

[0118] The difference between this comparative example and Example 1 is that the aging pH value is 11.0.

[0119] Comparative Example 6

[0120] The difference between this comparative example and Example 1 is that the aging pH value is 12.5.

[0121] Test example

[0122] The precursors obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were observed by scanning electron microscope, and the results are as follows: Figures 1 to 9 shown.

[0123] Depend on Figures 1 to 4 It can be seen that in nickel 8 series and 9 series products, the particle size D 50 There is no cracking when the particle size is 12μm, and the particles of different sizes have good sphericity and are evenly distributed.

[0124] Depend on Figure 5 It can be seen that in the precursor obtained without adding additives, some secondary spherical particles are broken and have microcracks.

[0125] Depend on Figure 6 It can be seen that in the unaged precursor, a few secondary spherical particles have microcracks on the surface.

[0126] Depend on Figure 7 It can be seen that when too little additive is used, some secondary ball particles are broken and have microcracks.

[0127] Depend on Figure 8 It can be seen that when too much additive is used, the secondary balls will agglomerate seriously in the early stage of the reaction.

[0128] Depend on Fig. 9 It can be seen that when the aging pH is too low, there are microcracks on the surface of the secondary ball particles.

[0129] In summary, the preparation method of the high-nickel large-particle precursor provided by the present invention not only solves the problem of easy cracking of the high-nickel large-particle precursor product by combining step-by-step co-precipitation, the use of additives and aging under specific conditions, but also realizes the mixing of large and small particles at the precursor reaction end, reducing the mixing of large and small particles of the rear-end precursor or the mixing of large and small particles at the positive electrode material end. The preparation method is simple to operate, has strong economies of scale, and is conducive to industrial production. The prepared high-nickel ternary large-particle precursor secondary particles have good sphericity, relatively wide distribution, and contain large and small particles at the same time, which is beneficial to improving the cycle performance and safety performance of downstream battery products.

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-nickel large-particle precursor, characterized in that: The general chemical formula of the high nickel large particle precursor is Ni x Co y Mn z (OH)2, where x+y+z=1, 0.8≤x<1, 0 <y<0.2,0<z<0.2; The preparation of the high-nickel large particle precursor comprises the following steps: A metal salt solution, a precipitant solution and a complexing agent solution are added to a first reaction container having a base solution in parallel, and a first coprecipitation reaction is carried out under stirring until a core is generated and grows to D 50 The first slurry containing nickel, cobalt and manganese hydroxide is 5 μm to 8 μm, wherein the reaction temperature of the first coprecipitation reaction is 50° C. to 65° C., the ammonia value is controlled to be 6 g / L to 9 g / L, the pH value is adjusted to 11.7 to 11.9 after 2 hours of reaction, and the pH value is adjusted to 11.3 to 11.6 after 10 hours of reaction; The first slurry is transferred to a second reaction container, and a metal salt solution, a precipitant solution, an additive solution and a complexing agent solution are added simultaneously in a parallel flow manner, and a second coprecipitation reaction is carried out under stirring conditions to obtain a second slurry; wherein the reaction temperature of the second coprecipitation reaction is 50° C. to 65° C., the ammonia value is controlled to be 4 g / L to 12 g / L, and the reaction pH value is controlled to be 11.3 to 11.6; The second slurry is concentrated until the material reaches D 50 10μm~15μm; Will grow to D 50 The material with a size of 10 μm to 15 μm is aged, wherein the aging is carried out at 55° C. to 70° C. and a pH of 11.9 to 12.2 for 4 h to 10 h.

2. The preparation method according to claim 1, characterized in that: The metal salt solution is a mixed solution containing nickel salt, cobalt salt and manganese salt; the total concentration of metal ions in the metal salt solution is 1 mol / L to 3 mol / L, and the molar ratio of Ni, Co and Mn is x:y:z; Preferably, the form of the metal salt in the metal salt solution includes at least one of sulfate, nitrate and halogen salt.

3. The preparation method according to claim 1, characterized in that: The additive in the additive solution is an organic compound surfactant; Preferably, the additive comprises sodium lauryl sulfate; Preferably, the concentration of the additive solution is 0.8 mol / L to 1.5 mol / L; Preferably, the molar ratio of the additive in the additive solution to the metal salt in the metal salt solution is 0.06:1 to 0.13:

1.

4. The preparation method according to claim 1, characterized in that: The precipitant solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 4 mol / L to 12 mol / L.

5. The preparation method according to claim 1, characterized in that: The complexing agent solution is ammonia water or ammonium salt solution with a concentration of 4g / L to 12g / L; Preferably, the ammonium salt solution comprises ammonium sulfate solution; Preferably, the mass fraction of aqueous ammonia is 18% to 23%.

6. The preparation method according to claim 1, characterized in that: The flow rate of the metal salt solution is 40 mL / min to 80 mL / min.

7. The preparation method according to claim 1, characterized in that: The stirring speed is 300 rpm to 900 rpm.

8. A high-nickel large particle precursor, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 7.

9. A positive electrode material, characterized in that: The precursor of the positive electrode material is the high-nickel large-particle precursor described in claim 8.

10. A battery, characterized in that: The raw materials for preparing the battery include the positive electrode material according to claim 9.

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