Positive electrode material precursor and preparation method and application thereof

Abstract

The invention discloses a positive electrode material precursor and a preparation method and application thereof, and belongs to the technical field of battery materials. The precursor has an inner core layer and an outer surface layer; the structural formula of the inner core layer is Ni < x > < 1 > Co < y > < 1 > M < 11-x-y > 1 (OH) 2, 0 lt; x1lt; 1, 0lt; y < 1lt >; 1, x1 + y1lt; 1; the structural formula of the outer surface layer is Ni < x > < 2 > Co < y > < 2 > M < 21-x-y > 2 (OH) 2, 0 lt; x2lt; x2lt; 1, 0lt; y2lt; y2lt; 1, x2 + y2lt; 1; m1 and M2 independently comprise elements such as Mn and / or Al; the Dv50 of the precursor is 8 [mu] m-18 [mu] m, the Dv0 is greater than 3.0 [mu] m, and the Dv99lt is greater than 99 [mu] m; the particle size is 30 microns, and the Span is 0.8-1.2. The particle size distribution of the precursor is relatively concentrated, and the uniformity and consistency of the product are relatively good, so that a downstream battery product has relatively good cycle performance and relatively long service life. The preparation method of the precursor is relatively simple and relatively low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and in particular, to a cathode material precursor, a preparation method thereof, and an application thereof. Background Art

[0002] At present, the production methods of ternary cathode material precursors are mainly divided into two types. One is batch production, which has a high cost and the produced products have a low tap density. The other is continuous production, and the products produced by this production method have a wide particle size distribution and the particle sizes are normally distributed, which easily leads to poor cycle performance and short life of downstream battery products.

[0003] Therefore, how to prepare a cathode material precursor that is conducive to improving the life of downstream battery products under the condition of low cost has become an urgent problem to be solved in this field.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a cathode material precursor, a preparation method thereof, and an application thereof to solve or improve the above technical problems.

[0006] The present invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a cathode material precursor, which has a core layer and an outer surface layer; the structural formula of the core layer is Ni x1 Co y1 M1 1-x1-y1 (OH)2, where 0 < x1 < 1, 0 < y1 < 1, and x1 + y1 < 1; M1 includes at least one of Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb elements; the structural formula of the outer surface layer is Ni x2 Co y2 M2 1-x2-y2 (OH)2, where 0 < x2 < 1, 0 < y2 < 1, and x2 + y2 < 1; M2 includes at least one of Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb elements;

[0008] The cathode material precursor is a spherical-like particle, the Dv50 of the cathode material precursor is 8 μm to 18 μm, Dv0 > 3.0 μm, Dv99 < 30 μm, and the Span of the cathode material precursor is 0.8 to 1.2, where Span = (Dv90 - Dv10) / Dv50.

[0009] In an optional embodiment, the cathode material precursor further has at least one of the following characteristics:

[0010] Feature 1: The cathode material precursor has a radial structure; preferably, the outer layer is radial;

[0011] Feature 2: In the XRD pattern of the cathode material precursor, the intensity ratio of the (001) diffraction peak to the (101) diffraction peak is 0.80 to 1.10, preferably 0.90 to 1.00;

[0012] Feature 3: The elements contained in the inner core layer and the outer surface layer are independently non-uniformly distributed; preferably, the non-uniform distribution is a gradient distribution;

[0013] Feature 4: Both the inner core layer and the outer surface layer contain Ni and Co, the concentration of Ni contained in the inner core layer is higher than the concentration of Ni contained in the outer surface layer, and the concentration of Co contained in the inner core layer is lower than the concentration of Co contained in the outer surface layer.

[0014] In a second aspect, the present invention provides a method for preparing a cathode material precursor according to the aforementioned embodiment, comprising the following steps:

[0015] A soluble metal salt solution a1, a first alkaline solution, and a first complexing agent are introduced into a first reaction device and subjected to a first precipitation reaction under stirring to obtain a seed slurry; wherein the soluble metal salt solution a1 is obtained by dissolving a Ni source, a Co source, and an M1 source in water at a molar ratio of Ni, Co, and M1 of x1:y1:(1-x1-y1);

[0016] A soluble metal salt solution a2, a second alkaline solution, a second complexing agent, and at least a portion of the seed slurry overflowing from the first reaction device are introduced into a second reaction device, and a second precipitation reaction is carried out under stirring to obtain a reaction slurry; wherein the soluble metal salt solution a2 is obtained by dissolving a Ni source, a Co source, and an M2 source in water at a molar ratio of Ni, Co, and M2 of x2:y2:(1-x2-y2);

[0017] The reaction slurry is continuously overflowed into the particle size classification device for powder separation, and large particles reaching the preset particle size and small particle powders that do not reach the preset particle size are separated. The slurry containing large particles is continuously passed into the aging device for aging, and the small particle powder is returned to the first reaction device for continued growth.

[0018] In an optional embodiment, the first precipitation reaction comprises at least one of the following conditions:

[0019] Condition 1: The total concentration of metal elements in the soluble metal salt solution a1 is 1.2 mol / L to 2.5 mol / L;

[0020] Condition 2: The concentration of the alkali in the first alkali solution is 30 wt% to 50 wt%, and the first alkali solution is used to control the pH value of the first precipitation reaction to be 11 to 13; preferably, the first alkali solution includes at least one of a NaOH solution and a KOH solution;

[0021] Condition 3: The first complexing agent is aqueous ammonia with a concentration not exceeding 30 wt %, and the concentration of ammonia in the first reaction device is 0.5 g / L to 10 g / L, preferably 2.5 g / L to 6 g / L;

[0022] Condition 4: In the first reaction device, the soluble metal salt solution a1 is fed at an hourly rate of 3% to 10% of the total volume of the first reaction device;

[0023] Condition 5: The temperature of the first precipitation reaction is 40°C to 80°C, preferably 60°C to 75°C;

[0024] Condition 6: The stirring speed of the first precipitation reaction is 100 rpm to 700 rpm, preferably 300 rpm to 600 rpm;

[0025] Condition 7: The Dv50 of the seed crystals in the seed crystal slurry is 2 μm to 8 μm.

[0026] In an optional embodiment, the seed slurry continuously overflowing from the first reaction device is first passed into the seed storage device, and then passed from the seed storage device into the second reaction device as needed.

[0027] In an optional embodiment, the second precipitation reaction comprises at least one of the following conditions:

[0028] Condition 8: The total concentration of metal elements in the soluble metal salt solution a2 is 1.2 mol / L to 2.5 mol / L;

[0029] Condition 9: The concentration of the alkali in the second alkaline solution is 30 wt% to 50 wt%, and the second alkaline solution is used to control the pH value of the second precipitation reaction to be 9.5 to 12, and the pH value of the second precipitation reaction is lower than the pH value of the first precipitation reaction; preferably, the pH value of the second precipitation reaction is 10 to 11; preferably, the second alkaline solution comprises at least one of a NaOH solution and a KOH solution;

[0030] Condition 10: The second complexing agent is aqueous ammonia with a concentration not exceeding 30 wt %, and the concentration of ammonia in the second reaction device is 0.5 g / L to 10 g / L, preferably 2.5 g / L to 6 g / L;

[0031] Condition 11: In the second reaction device, the soluble metal salt solution a2 is fed at an hourly rate of 3% to 10% of the total volume of the second reaction device;

[0032] Condition 12: In the second reaction apparatus, the flow rate of the seed slurry is 10 L / h to 30 L / h;

[0033] Condition 13: The temperature of the second precipitation reaction is 40°C to 80°C, preferably 60°C to 75°C;

[0034] Condition 14: The stirring speed of the second precipitation reaction is 100 rpm to 700 rpm, preferably 300 rpm to 600 rpm.

[0035] In an optional embodiment, the particle size classification device is selected from a tubular centrifuge, a butterfly centrifuge or a horizontal screw centrifuge.

[0036] In an optional embodiment, the method further includes washing, dehydrating and drying the aged slurry.

[0037] In a third aspect, the present invention provides a positive electrode material, which is prepared from the positive electrode material precursor of the aforementioned embodiment.

[0038] In a fourth aspect, the present invention provides a battery comprising the positive electrode material according to the aforementioned embodiment.

[0039] The beneficial effects of the present invention include:

[0040] The cathode material precursor provided by the present invention has a relatively concentrated particle size distribution, good product uniformity and consistency, which is conducive to the good cycle performance and service life of downstream battery products. The preparation method of this cathode material precursor is relatively simple and low-cost. By adopting a continuous production method combined with seed slurry preparation and particle size classification processes, it fully utilizes the production capacity advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 is a process flow chart of the preparation method of the positive electrode material precursor in Example 1;

[0043] Figure 2 This is a SEM image of the cathode material precursor prepared in Example 1;

[0044] Figure 3 CP diagram of the cross section of the cathode material precursor prepared in Example 1;

[0045] Figure 4SEM image of the cathode material precursor obtained in Comparative Example 1;

[0046] Figure 5 Cross-sectional CP image of the cathode material precursor obtained in Comparative Example 1;

[0047] Figure 6 SEM image of the cathode material precursor obtained in Comparative Example 2. Detailed implementation manners

[0048] 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. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchases.

[0049] The cathode material precursor provided by the present invention, its preparation method, and application will be specifically described below.

[0050] The present invention provides a cathode material precursor, which has a core layer and an outer surface layer.

[0051] The structural formula of the core layer is Ni x1 Co y1 M1 1-x1-y1 (OH)2, where 0 < x1 < 1, 0 < y1 < 1, x1 + y1 < 1; M1 includes at least one of the elements Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb.

[0052] The structural formula of the outer surface layer is Ni x2 Co y2 M2 1-x2-y2 (OH)2, where 0 < x2 < 1, 0 < y2 < 1, x2 + y2 < 1; M2 includes at least one of the elements Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb.

[0053] In the present invention, M1 and M2 can be the same element or different elements; the values of x1 and x2 can be equal or unequal; the values of y1 and y2 can be equal or unequal, and specific settings are made according to actual needs.

[0054] The cathode material precursor provided by the present invention is spherical-like particles, with a Dv50 of 8 μm to 18 μm, Dv0 > 3.0 μm, Dv99 < 30 μm, and the Span of the cathode material precursor is 0.8 to 1.2, Span = (Dv90 - Dv10) / Dv50.

[0055] In some optional embodiments, Dv50 may be 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm or 18 μm, or other values ​​within the range of 8 μm to 18 μm.

[0056] The value of Span may be 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15 or 1.2, or other values ​​within the range of 0.8 to 1.2.

[0057] The above-mentioned Dv50, Dv0, Dv99, Dv90, and Dv10 are all obtained through laser particle size analysis. For example, Dv50 represents the particle size corresponding to the 50% cumulative value of the volume distribution. The meanings of Dv99, Dv90, and Dv10 can be understood in the same way as Dv50. Dv0 represents the minimum particle diameter detected by the laser particle size analyzer.

[0058] The particle size distribution of the positive electrode material precursor that meets the above-mentioned Dv50, Dv0, Dv99 and Span ranges is more concentrated, and the product uniformity and consistency are better, which is conducive to making the downstream battery products have better cycle performance and service life.

[0059] In some optional embodiments, the cathode material precursor provided by the present invention has a radial structure, and the location of the radial structure is not limited. In some more typical embodiments, the outer layer of the cathode material precursor is radial. In some more typical embodiments, the inner core layer of the cathode material precursor is disordered and the outer layer is radial. This structure is conducive to providing a uniform and shorter transmission path for lithium ions in the prepared cathode material during the battery charging and discharging process, thereby improving the capacity and cycle performance of the lithium-ion battery.

[0060] In some optional embodiments, in the XRD pattern of the cathode material precursor provided by the present invention, the intensity ratio of the (001) diffraction peak to the (101) diffraction peak is 0.80 to 1.10, such as 0.8, 0.85, 0.9, 0.95, 1, 1.05, or 1.1, or other values ​​within the range of 0.80 to 1.10. In some more typical embodiments, the intensity ratio of the (001) diffraction peak to the (101) diffraction peak is 0.90 to 1.00. Within this range, downstream battery products have better cycle performance.

[0061] In some optional embodiments, the elements contained in the inner core layer and outer shell layer of the cathode material precursor are independently uniformly distributed or non-uniformly distributed. The terms "uniform" and "non-uniform" specifically refer to the concentrations of the elements. For example, all elements in the inner core layer and outer shell layer are uniformly distributed; for example, all elements in the inner core layer and outer shell layer are non-uniformly distributed; for example, some elements in the inner core layer and outer shell layer are uniformly distributed, while others are non-uniformly distributed. In some embodiments, the non-uniform distribution is a gradient distribution.

[0062] In some optional embodiments, the inner core layer and outer layer of the positive electrode material precursor both contain Ni and Co, the inner core layer has a higher Ni concentration than the outer layer, and the inner core layer has a lower Co concentration than the outer layer. In other words, the inner core layer has high Ni and low Co, while the outer layer has low Ni and high Co. This specific Ni and Co concentration setting is beneficial for reducing the nickel-lithium mixing phenomenon on the surface of the high-nickel material, thereby improving the capacity of the positive electrode material. In addition, the high Co distribution on the surface is beneficial for stabilizing the outer layer structure and improving the cycle performance of the positive electrode material.

[0063] Accordingly, the present invention also provides a method for preparing the above-mentioned cathode material precursor, comprising the following steps:

[0064] S1: A soluble metal salt solution a1, a first alkaline solution, and a first complexing agent are flowed into a first reaction device, and a first precipitation reaction is carried out under stirring conditions to obtain a seed slurry; wherein the soluble metal salt solution a1 is obtained by dissolving a Ni source, a Co source, and an M1 source in water at a molar ratio of Ni, Co, and M1 of x1:y1:(1-x1-y1).

[0065] In some optional embodiments, the total concentration of metal elements in the soluble metal salt solution a1 can be 1.2 mol / L to 2.5 mol / L, such as 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L or 2.5 mol / L, or other values ​​within the range of 1.2 mol / L to 2.5 mol / L.

[0066] The Ni source in the soluble metal salt solution a1 may exemplarily include at least one of nickel sulfate, nickel nitrate and nickel chloride; the Co source in the soluble metal salt solution a1 may exemplarily include at least one of cobalt sulfate, cobalt nitrate and cobalt chloride; the M1 source in the soluble metal salt solution a1 may exemplarily include at least one of sulfate, nitrate, chloride, acetate and acetate of the M1 element.

[0067] In some optional embodiments, the concentration of the alkali in the first alkaline solution can be 30 wt% to 50 wt%, such as 30 wt%, 35 wt%, 40 wt%, 45 wt% or 50 wt%, or other values ​​within the range of 30 wt% to 50 wt%.

[0068] The amount of the first alkaline solution introduced is based on controlling the pH value of the first precipitation reaction to be 11 to 13. For example, the pH value of the first precipitation reaction can be 11, 11.5, 12, 12.5, or 13, or other values ​​within the range of 11 to 13.

[0069] Illustratively, the first alkaline solution may include at least one of a NaOH solution and a KOH solution.

[0070] In some optional embodiments, the first complexing agent may include at least one of aqueous ammonia, EDTA, sodium citrate, and sodium oxalate.

[0071] Exemplarily, the first complexing agent is an ammoniacal liquor having a concentration no more than 30wt%, such as 30wt%, 25wt%, 20wt%, 15wt%, 10wt% or the like, or other values ​​within the range of no more than 30wt%. The amount of ammoniacal liquor introduced is such that the concentration of ammonia in the first reaction unit is 0.5g / L to 10g / L. For example, the concentration of ammonia in the first reaction unit can be 0.5g / L, 1g / L, 2g / L, 3g / L, 4g / L, 5g / L, 6g / L, 7g / L, 8g / L, 9g / L or 10g / L or the like, or other values ​​within the range of 0.5g / L to 10g / L. In some preferred embodiments, the concentration of ammonia in the first reaction unit can be 2.5g / L to 6g / L.

[0072] In some optional embodiments, in the first reaction device (such as a reactor), the hourly liquid inflow rate of the soluble metal salt solution a1 can be 3% to 10% of the total volume of the first reaction device, such as 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., or other values ​​within the range of 3% to 10%.

[0073] In some optional embodiments, the temperature of the first precipitation reaction can be 40° C. to 80° C., such as 40° C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., or 80° C., or other values ​​within the range of 40° C. to 80° C. In some preferred embodiments, the temperature of the first precipitation reaction is 60° C. to 75° C.

[0074] In some optional embodiments, the stirring speed of the first precipitation reaction can be 100 r / min to 700 r / min, such as 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min or 700 r / min, or other values ​​within the range of 100 r / min to 700 r / min. In some preferred embodiments, the stirring speed is 300 rpm to 600 rpm.

[0075] In some optional embodiments, the Dv50 of the seed crystals in the seed crystal slurry is 2 μm to 8 μm.

[0076] In some optional embodiments, the seed slurry continuously overflowing from the first reaction device is first passed into a seed storage device (such as a seed tank) for transit storage, and then passed from the seed storage device into the second reaction device (such as a reactor) as needed.

[0077] S2: The soluble metal salt solution a2, the second alkaline solution, the second complexing agent and at least part of the seed slurry overflowing from the first reaction device are flowed into the second reaction device, and a second precipitation reaction is carried out under stirring conditions to obtain a reaction slurry; wherein the soluble metal salt solution a2 is obtained by dissolving a Ni source, a Co source and an M2 source in water at a molar ratio of Ni, Co and M2 of x2:y2:(1-x2-y2).

[0078] In some optional embodiments, the total concentration of metal elements in the soluble metal salt solution a2 can be 1.2 mol / L to 2.5 mol / L, such as 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L or 2.5 mol / L, etc., or it can be other values ​​within the range of 1.2 mol / L to 2.5 mol / L.

[0079] Similarly, the Ni source in the soluble metal salt solution a2 can exemplarily include at least one of nickel sulfate, nickel nitrate and nickel chloride; the Co source in the soluble metal salt solution a2 can exemplarily include at least one of cobalt sulfate, cobalt nitrate and cobalt chloride; the M2 source in the soluble metal salt solution a2 can exemplarily include at least one of sulfate, nitrate, chloride, acetate and acetate of the M2 element.

[0080] In some optional embodiments, the concentration of the alkali in the second alkaline solution can be 30wt% to 50wt%, such as 30wt%, 35wt%, 40wt%, 45wt% or 50wt%, or other values ​​within the range of 30wt% to 50wt%.

[0081] The amount of the second alkaline solution introduced is based on controlling the pH value of the second precipitation reaction to be between 9.5 and 12. For example, the pH value of the second precipitation reaction can be 9.5, 10, 10.5, 11, 11.5, or 12, or other values ​​within the range of 9.5 to 12. In some preferred embodiments, the pH value of the second precipitation reaction is between 10 and 11. It should be noted that the pH value of the second precipitation reaction is lower than that of the first precipitation reaction.

[0082] Illustratively, the second alkaline solution may also include at least one of a NaOH solution and a KOH solution.

[0083] In some optional embodiments, the second complexing agent may include at least one of aqueous ammonia, EDTA, sodium citrate, and sodium oxalate.

[0084] Exemplarily, the second complexing agent is an ammoniacal liquor having a concentration no more than 30wt%, such as 30wt%, 25wt%, 20wt%, 15wt%, 10wt% or the like, or other values ​​no more than 30wt%. The amount of ammoniacal liquor introduced is such that the concentration of ammonia in the second reaction unit is 0.5g / L to 10g / L. For example, the concentration of ammonia in the second reaction unit can be 0.5g / L, 1g / L, 2g / L, 3g / L, 4g / L, 5g / L, 6g / L, 7g / L, 8g / L, 9g / L or 10g / L or the like, or other values ​​within the range of 0.5g / L to 10g / L. In some preferred embodiments, the concentration of ammonia in the second reaction unit can be 2.5g / L to 6g / L.

[0085] In some optional embodiments, in the second reaction device, the hourly liquid inflow rate of the soluble metal salt solution a2 can be 3% to 10% of the total volume of the second reaction device, such as 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., or other values ​​within the range of 3% to 10%.

[0086] In some optional embodiments, in the second reaction device, the flow rate of the seed slurry can be 10L / h to 30L / h (such as 10L / h, 15L / h, 20L / h, 25L / h or 30L / h, etc.), and the particle size in the second reactor is maintained by controlling the flow rate of the seed slurry.

[0087] In some optional embodiments, the temperature of the second precipitation reaction is 40° C. to 80° C., such as 40° C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., or 80° C., or other values ​​within the range of 40° C. to 80° C. In some preferred embodiments, the temperature of the second precipitation reaction is 60° C. to 75° C.

[0088] In some optional embodiments, the stirring speed of the second precipitation reaction can be 100 r / min to 700 r / min, such as 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min or 700 r / min, or other values ​​within the range of 100 r / min to 700 r / min. In some preferred embodiments, the stirring speed is 300 rpm to 600 rpm.

[0089] In the above process, the size of the generated particles is adjusted by adjusting the flow rate of the seed slurry introduced into the second reaction device, so that the particle size obtained by the second precipitation reaction meets the range of Dv50 of 8μm to 18μm, Dv0>3.0μm, Dv99<30μm, and Span of 0.8 to 1.2.

[0090] S3: The reaction slurry is continuously overflowed into the particle size classification device for fine powder separation, and large particles reaching the preset particle size and small particles that do not reach the preset particle size are separated. The slurry containing large particles is continuously passed into the aging device (such as an aging tank) for aging, and the small particles are returned to the first reaction device for continued growth.

[0091] The above-mentioned fine powder separation is carried out by wet classification.

[0092] It should be noted that the present invention does not return the small-particle micropowder to the second reaction device for continued growth but returns it to the first reaction device for continued growth. The reason is that the second reaction device is close to the particle size classification device, and it is possible that some small-particle micropowder will repeatedly circulate on the circulation path from the second reaction device to the particle size classification device and cannot grow, which will affect the product particle size distribution and growth efficiency.

[0093] In some optional embodiments, the particle size classification device is selected from a tubular centrifuge, a butterfly centrifuge, or a decanter centrifuge. In some preferred embodiments, the particle size classification device is a decanter centrifuge. Compared to traditional hydrocyclones, such particle size classification devices can more efficiently and specifically separate large and small particles, and the process control is simple and stable.

[0094] Furthermore, the method for preparing the cathode material precursor provided by the present invention further comprises:

[0095] S4: washing, dehydrating and drying the aged slurry, and further screening the dried product in mixed batches.

[0096] It should be noted that by adjusting the elemental composition of the soluble metal salt solution a1, the total concentration of metal elements in the soluble metal salt solution a1, the elemental composition of the soluble metal salt solution a2, the total concentration of metal elements in the soluble metal salt solution a2, the pH value of the first precipitation reaction, the pH value of the second precipitation reaction, the first complexing agent concentration of the first precipitation reaction, the second complexing agent concentration of the second precipitation reaction, etc., a positive electrode material precursor with different elemental composition or different element distribution can be obtained. Therefore, the preparation method provided by the present invention can design different positive electrode material precursor schemes according to needs, thereby optimizing the physical and chemical properties of the positive electrode material precursor. Among them, the different element types or element concentrations in the inner core layer and the outer surface layer of the positive electrode material precursor are beneficial to making the ion transport of the positive electrode material smoother during the charge and discharge process, and effectively improving the capacity retention rate of downstream battery products.

[0097] Continuing from the above, the present invention utilizes a continuous production method, combined with a unique seed slurry preparation and particle size classification process, to fully leverage its production capacity advantages. In a one-month large-scale production experiment, compared to traditional batch production, the present invention increased capacity utilization by 20% to 40%, and reduced manufacturing costs by approximately 20%. Furthermore, the product produced by the method provided by the present invention has high quality stability and batch consistency.

[0098] In addition, the present invention also provides a positive electrode material, which is prepared from the positive electrode material precursor.

[0099] In some optional embodiments, the positive electrode material is obtained by mixing the above-mentioned positive electrode material precursor with a lithium source and then calcining it.

[0100] The lithium source may include lithium hydroxide. The molar ratio of the cathode material precursor to the lithium source is 1:1 to 1:1.1 (e.g., 1:1, 1:1.05, or 1:1.1). The calcination temperature may be 6 hours to 12 hours (e.g., 6 hours, 8 hours, 10 hours, or 12 hours), and the calcination time may be 600°C to 1000°C (e.g., 600°C, 700°C, 800°C, 900°C, or 1000°C). The calcination atmosphere may be air or oxygen.

[0101] In addition, the present invention also provides a battery cell, the positive electrode material of the battery cell includes the above positive electrode material.

[0102] For example, the battery cells can be used in, but are not limited to, electrical devices such as vehicles, ships, or aircraft.

[0103] The present invention also provides a battery comprising the above battery cell.

[0104] The present invention also provides an electrical device comprising the aforementioned battery cell and / or battery. For example, the electrical device may include, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, and the like. The electric toy may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. The spacecraft may include airplanes, rockets, space shuttles, and spacecraft.

[0105] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0106] Example 1

[0107] This embodiment provides a positive electrode material precursor, such as Figure 1 As shown, the preparation method includes:

[0108] S1: Soluble metal salt solution a1, a first alkaline solution, and a first complexing agent are introduced into a first reaction apparatus (a first reactor with a total volume of 500 L) for a first precipitation reaction under stirring to produce a seed slurry. The overflowing seed slurry is continuously transferred to a seed storage apparatus (seed tank) for intermediate storage.

[0109] The soluble metal salt solution a1 is prepared by adding deionized water to nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of Ni, Co, and Mn of x1:y1:(1-x1-y1)=0.97:0.02:0.01. The total concentration of metal elements in the soluble metal salt solution a1 is 2.0 mol / L.

[0110] The first alkaline solution is a NaOH aqueous solution, the concentration of NaOH in the NaOH aqueous solution is 32 wt %, and the first alkaline solution is added to control the pH value of the first precipitation reaction to be 11.60±0.1.

[0111] The first complexing agent is ammonia water with a concentration of 10 wt %. The addition of the first complexing agent is used to control the concentration of ammonia in the first reaction kettle to be 3 g / L.

[0112] The soluble metal salt solution a1 was fed at a flow rate of 25 L / h (i.e., the hourly flow rate of the soluble metal salt solution a1 into the first reactor was 5% of the total volume of the first reactor). Sodium hydroxide solution and aqueous ammonia were simultaneously fed into the first reactor, with their flow rates adjusted based on the set pH value and ammonia concentration. The temperature of the first precipitation reaction was 65°C; the stirring speed during the first precipitation reaction was 400 rpm; and the Dv50 of the seed crystals was controlled to 6.5 ± 0.5 μm by adjusting the pH fluctuation.

[0113] S2: The soluble metal salt solution a2, the second alkaline solution, the second complexing agent and the seed slurry in the seed tank are flowed into a second reaction device (a second reactor with a total volume of 500 L), and a second precipitation reaction is carried out under stirring conditions to obtain a reaction slurry.

[0114] Among them, the soluble metal salt solution a2 is prepared by adding deionized water to nickel sulfate, cobalt sulfate and manganese sulfate according to the molar ratio of Ni, Co and Mn of x2:y2:(1-x2-y2)=0.83:0.10:0.07, and the total concentration of metal elements in the soluble metal salt solution a2 is 2.0 mol / L.

[0115] The second alkaline solution is a NaOH aqueous solution, the concentration of NaOH in the NaOH aqueous solution is 32 wt %, and the addition of the second alkaline solution is used to control the pH value of the second precipitation reaction to be 10.60±0.1.

[0116] The second complexing agent is ammonia water with a concentration of 20 wt %. The addition of the second complexing agent is used to control the concentration of ammonia in the second reaction kettle to be 3.5 g / L.

[0117] The soluble metal salt solution a2 was fed at a flow rate of 30 L / h (i.e., the hourly flow rate of the soluble metal salt solution a2 into the second reactor was 6% of the total volume of the second reactor). Aqueous sodium hydroxide solution and aqueous ammonia were simultaneously fed into the second reactor, with their flow rates adjusted according to the set pH value and ammonia concentration. The temperature of the second precipitation reaction was 65°C; the stirring speed of the second precipitation reaction was 450 rpm; and the flow rate of the seed slurry was 10 L / h to 30 L / h. The seed slurry flow rate was controlled to maintain the particle size Dv50 in the second reactor at 12.5 ± 0.5 μm.

[0118] S3: The reaction slurry in the second reactor continuously overflows into a particle size classification device (butterfly centrifuge) for fine powder separation. The centrifuge speed is adjusted to separate large particles that reach the preset particle size (≥ Dv50 in S2) and small particles that do not reach the preset particle size. The slurry containing large particles is continuously passed into an aging device (aging tank) for aging, and the small particles are returned to the first reactor for further growth.

[0119] S4: The finished slurry in the aging tank is washed multiple times by continuous washing equipment to remove impurity ions, and then dehydrated and finally dried in an oven at 120°C to obtain a positive electrode material precursor in the form of spherical particles.

[0120] The SEM image of the cathode material precursor prepared in this example is as follows: Figure 2 As shown, the cross-sectional CP diagram is as follows Figure 3 As shown. Combined Figure 2 and Figure 3It can be seen that the cathode material precursor prepared in this embodiment has an inner core layer and an outer layer. The structural formula of the inner core layer is Ni 0.97 Co 0.02 Mn 0.01 (OH)2, the structural formula of the outer layer is Ni 0.83 Co 0.10 Mn 0.07 (OH)2. The inner core layer of the cathode material precursor has a disordered structure, and the outer layer has a radial structure.

[0121] Example 2

[0122] The difference between this embodiment and embodiment 1 is that:

[0123] The soluble metal salt solution a1 is prepared by adding deionized water to nickel nitrate, cobalt nitrate, and manganese nitrate in a molar ratio of Ni, Co, and Mn of x1:y1:(1-x1-y1)=0.90:0.06:0.04. The total concentration of metal elements in the soluble metal salt solution a1 is 2.0 mol / L.

[0124] Soluble metal salt solution a2 is prepared by adding nickel nitrate, cobalt nitrate, and a nitrate of the M2 element to deionized water in a molar ratio of Ni, Co, and M2 of x2:y2:(1-x2-y2)=0.90:0.06:0.04. The total concentration of the metal elements in the soluble metal salt solution a2 is 2.0 mol / L. The M2 elements include Mn and Zr, and the molar ratio of Mn to Zr is 3:1.

[0125] The temperature of the first precipitation reaction is 68° C., the stirring speed is 450 rpm, the hourly liquid inflow rate of the soluble metal salt solution a1 in the first reactor is 6% of the total volume of the first reactor, and the addition of the first alkaline solution is used to control the pH value of the first precipitation reaction to 11.40±0.1.

[0126] The temperature of the second precipitation reaction was 68° C., the stirring speed was 350 rpm, and the hourly rate of the soluble metal salt solution a2 in the second reactor was 6% of the total volume of the second reactor. The particle size Dv50 in the second reactor was 10.0±0.5 μm.

[0127] The particle size classification device is a horizontal screw centrifuge.

[0128] Example 3

[0129] The difference between this embodiment and embodiment 1 is that:

[0130] The soluble metal salt solution a1 is prepared by adding deionized water to nickel sulfate, cobalt sulfate, and aluminum sulfate in a molar ratio of Ni, Co, and Al of x1:y1:(1-x1-y1)=0.82:0.15:0.03. The total concentration of metal elements in the soluble metal salt solution a1 is 2.0 mol / L.

[0131] The soluble metal salt solution a2 is prepared by adding deionized water to nickel nitrate, cobalt nitrate, and manganese nitrate in a molar ratio of Ni, Co, and Mn of x2:y2:(1-x2-y2)=0.82:0.15:0.03. The total concentration of metal elements in the soluble metal salt solution a2 is 2.0 mol / L.

[0132] The temperature of the first precipitation reaction is 68° C., the stirring speed is 450 rpm, the hourly liquid inflow rate of the soluble metal salt solution a1 in the first reactor is 6% of the total volume of the first reactor, and the addition of the first alkaline solution is used to control the pH value of the first precipitation reaction to 11.20±0.2.

[0133] The temperature of the second precipitation reaction was 68° C., the stirring speed was 350 rpm, and the hourly rate of the soluble metal salt solution a2 in the second reactor was 6% of the total volume of the second reactor. The particle size Dv50 in the second reactor was 10.0±0.5 μm.

[0134] The particle size classification device is a tubular centrifuge.

[0135] Comparative Example 1

[0136] This comparative example provides a positive electrode material precursor prepared by a continuous production method, and the preparation method thereof includes:

[0137] S1: A soluble metal salt solution, a NaOH aqueous solution and an ammonia solution are flowed into a first reaction device (a first reactor with a total volume of 500 L), and a first precipitation reaction is carried out under stirring to obtain a seed crystal slurry.

[0138] The soluble metal salt solution is prepared by adding deionized water to nickel sulfate, cobalt sulfate and manganese sulfate in a molar ratio of Ni, Co and Mn of x:y:(1-xy)=0.90:0.06:0.04, and the total concentration of metal elements in the soluble metal salt solution is 2.0 mol / L.

[0139] The concentration of NaOH in the NaOH aqueous solution is 30 wt %. The addition of the NaOH aqueous solution is used to control the pH value of the first precipitation reaction to be 11.5±0.1.

[0140] The concentration of the ammonia water is 15 wt %, and the addition of the ammonia water is used to control the ammonia concentration in the first reaction kettle to be 3 g / L.

[0141] The soluble metal salt solution was fed into the first reactor at a rate of 25 L / h (i.e., the hourly flow rate of the soluble metal salt solution into the first reactor was 5% of the total volume of the first reactor). The NaOH aqueous solution and ammonia solution were simultaneously fed into the first reactor, with their flow rates adjusted based on the desired pH and ammonia concentration. The temperature of the first precipitation reaction was 65°C; the stirring speed during the first precipitation reaction was 400 rpm; and the Dv50 of the seed crystals in the seed slurry was 3.0 ± 0.5 μm.

[0142] S2: Another portion of the soluble metal salt solution, NaOH aqueous solution, ammonia water and seed crystal slurry was taken and flowed into a second reaction device (a second reactor with a total volume of 500 L), and a second precipitation reaction was carried out under stirring to obtain a reaction slurry.

[0143] The soluble metal salt solution, NaOH aqueous solution, and ammonia water used in this step are the same as those in S1. The soluble metal salt solution is fed into the second reactor at a flow rate of 30 L / h (i.e., the hourly flow rate of the soluble metal salt solution into the second reactor is 6% of the total volume of the second reactor). The addition of the NaOH aqueous solution is used to control the pH value of the second precipitation reaction to 10.3±0.1, and the addition of ammonia water is used to control the ammonia concentration in the second reactor to 4 g / L. The temperature of the second precipitation reaction is 68°C; the stirring speed of the second precipitation reaction is 500 rpm; the seed slurry flow rate is 10 L / h to 20 L / h, and the particle size Dv50 in the second reactor is maintained at 10±0.5 μm by controlling the flow rate of the seed slurry.

[0144] S3: The prepared precursor finished slurry is washed multiple times by continuous washing equipment to remove impurity ions, then dehydrated, and finally dried in an oven at 120° C. to obtain a continuous precursor.

[0145] The SEM image of the cathode material precursor prepared in this comparative example is as follows: Figure 4 As shown, the cross-sectional CP diagram is as follows Figure 5 As shown. Combined Figure 4 and Figure 5 It can be seen that the positive electrode material precursor prepared in this comparative example has a wide particle size distribution, with more small particles and oversized spheres, and a disordered internal structure.

[0146] Comparative Example 2

[0147] This comparison provides a cathode material precursor prepared by a batch production method, the preparation method of which includes:

[0148] S1: Soluble metal salt solution, NaOH aqueous solution and ammonia water are flowed into a reactor with a total volume of 500L, and precipitation reaction is carried out under stirring conditions. The clear liquid in the reactor is continuously filtered using a concentrator. Finally, when the particle size Dv50 in the slurry is 13μm, the liquid addition is stopped to obtain a qualified intermittent precursor slurry.

[0149] The soluble metal salt solution is prepared by adding deionized water to nickel sulfate, cobalt sulfate and manganese sulfate in a molar ratio of Ni, Co and Mn of x:y:(1-xy)=0.90:0.06:0.04, and the total concentration of metal elements in the soluble metal salt solution is 2.0 mol / L.

[0150] The concentration of NaOH in the NaOH aqueous solution is 30 wt %, and the addition of the NaOH aqueous solution is used to control the pH value of the precipitation reaction to be 10.5±0.5.

[0151] The concentration of ammonia water is 10 wt %, and the addition of ammonia water is used to control the concentration of ammonia in the reactor to be 3 g / L.

[0152] The soluble metal salt solution was fed at a rate of 20 L / h (i.e., 4% of the total reactor volume per hour). The NaOH aqueous solution and ammonia solution were simultaneously flowed into the reactor, with their flow rates adjusted based on the desired pH and ammonia concentration. The precipitation reaction temperature was 65°C, and the stirring speed was 400 rpm.

[0153] S2: The prepared precursor slurry is washed multiple times by a washing device to remove impurity ions, then dehydrated, and finally dried in an oven at 120° C. to obtain an intermittent precursor.

[0154] The SEM image of the cathode material precursor prepared in this comparative example is as follows: Figure 6 As shown. Figure 6 It can be seen that the positive electrode material precursor prepared in this comparative example has a uniform particle size distribution.

[0155] Comparative Example 3

[0156] This comparative example provides a positive electrode material precursor prepared by a continuous production method, and the preparation method thereof includes:

[0157] S1: Soluble metal salt solution, NaOH aqueous solution and ammonia water are flowed into a reaction device (reactor with a total volume of 500L) and a precipitation reaction is carried out under stirring conditions. The particle size is controlled by controlling the pH level in the reactor to obtain a precursor finished slurry with a Dv50 of 10.0±1.0μm.

[0158] The soluble metal salt solution is prepared by adding deionized water to nickel sulfate, cobalt sulfate and manganese sulfate in a molar ratio of Ni, Co and Mn of x:y:(1-xy)=0.82:0.15:0.03, and the total concentration of metal elements in the soluble metal salt solution is 2.0 mol / L.

[0159] The concentration of NaOH in the NaOH aqueous solution is 30 wt %, and the addition of the NaOH aqueous solution is used to control the pH value of the precipitation reaction to be 11.5±0.3.

[0160] The concentration of ammonia water is 15 wt %, and the addition of ammonia water is used to control the concentration of ammonia in the reactor to be 3 g / L.

[0161] The soluble metal salt solution was fed into the reactor at a rate of 25 L / h (i.e., 5% of the total volume of the reactor per hour). The NaOH aqueous solution and ammonia solution were also fed into the reactor. The precipitation reaction temperature was 65°C, and the stirring speed was 400 rpm.

[0162] S2: The obtained precursor finished slurry is washed multiple times by continuous washing equipment to remove impurity ions, then dehydrated, and finally dried in an oven at 120° C. to obtain a continuous precursor.

[0163] Test Example 1

[0164] The particle size of the positive electrode material precursors obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was tested using a laser particle size analyzer. The results are shown in Table 1.

[0165] The cathode material precursors obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were tested using an X-ray diffractometer. In the XRD patterns, the intensity ratio of the (001) diffraction peak to the (101) diffraction peak is shown in Table 1.

[0166] Table 1 Test results

[0167] As can be seen from Table 1, the cathode material precursors prepared in Examples 1 to 3 of the present invention have narrower and more concentrated particle size distributions and higher particle consistency than those in Comparative Examples 1 and 3. The cathode material precursor prepared in Comparative Example 2 using a batch process has a uniform particle size distribution.

[0168] Test Example 2

[0169] The positive electrode material precursors obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were respectively prepared into positive electrode materials in the following manner, and further prepared into CR2430 button batteries. The initial discharge specific capacity of each battery at 1C and 2C charge rates was tested, and the capacity retention rate of the battery after 1C, 300 cycles and 2C, 100 cycles was tested. The results are shown in Table 2.

[0170] Preparation method of positive electrode material: a positive electrode material precursor is mixed with lithium hydroxide in a molar ratio of 1:1.05, and then calcined at a high temperature of 720°C in an oxygen atmosphere for 10 hours to obtain a positive electrode material.

[0171] The battery preparation method involves weighing the active material, conductive agent, and binder in a 90:5:5 mass ratio using acetylene black as the conductive material, and PVDF as the binder. A certain amount of the organic solvent, NMP, is added, stirred, and coated onto aluminum foil to form the positive electrode sheet. A metallic lithium sheet is used as the negative electrode. CR2430 button cells are fabricated in an argon-filled glove box. The electrical performance of these CR2430 button cells is tested using a CT2001A blue-electricity test system under the following test conditions: a voltage range of 3.0V to 4.25V, and a test temperature of 25±1°C.

[0172] Table 2 Test results

[0173] It can be seen from Table 2 that the downstream battery products further prepared from the positive electrode material precursors provided by Examples 1 to 3 are better than those of Comparative Examples 1 to 3 in terms of initial discharge capacity and capacity retention rate.

[0174] For example, in a test of 300 charge-discharge cycles, the capacity retention rate of the downstream battery product further prepared using the cathode material precursor provided in Example 2 of the present invention reached 95.3%. In contrast, the capacity retention rate of the downstream battery product of the cathode material precursor produced using the traditional continuous production method in Comparative Example 1 was only 87.6%. In comparison, the battery cycle life corresponding to Example 2 was improved by approximately 8.7% compared with Comparative Example 1, greatly satisfying the long battery life requirements of new energy vehicles. Although the cathode material precursor prepared using the batch method provided in Comparative Example 2 had a higher capacity retention rate after cycling, its initial discharge capacity was lower than that of Examples 1 and 2.

[0175] Taking Example 2 as an example, in a high-rate (2C) charge-discharge test, the corresponding battery achieved an initial discharge capacity of 208 mAh / g, and after 100 cycles, the capacity retention rate was still 93.2%. Under the same conditions, the corresponding battery of Comparative Example 1 achieved an initial discharge capacity of only 192 mAh / g, and the capacity retention rate after 100 cycles was only 83.7%. This shows that under high-rate charge-discharge conditions, the capacity retention rate of the battery corresponding to Example 2 was approximately 11.3% higher than that of the battery corresponding to Comparative Example 2, significantly enhancing the battery's rate and cycle performance.

[0176] The metal elements contained in the positive electrode material precursor of Comparative Example 3 are only Ni, Co, and Mn and no double-layer structure is formed, while Example 3 has an inner core layer and an outer layer, wherein the metal elements of the inner core layer are Ni, Co, and Al, and the metal elements of the outer layer are Ni, Co, and Mn. The Al in the inner core layer makes the inner core part looser, which is beneficial to improving the sintering activity of the material, thereby improving the capacity and cycle performance of the battery.

[0177] In summary, the cathode material precursor provided by the present invention has a relatively concentrated particle size distribution, good product uniformity and consistency, which is conducive to improving the cycle performance and service life of downstream battery products. The preparation method of the cathode material precursor is relatively simple and low-cost.

[0178] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A cathode material precursor, characterized in that: The cathode material precursor has a core layer and an outer surface layer; the structural formula of the core layer is Ni x1 Co y1 M1 1-x1-y1 (OH)2, where 0 < x1 < 1, 0 < y1 < 1, and x1 + y1 < 1; M1 includes at least one of the elements Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb; the structural formula of the outer surface layer is Ni x2 Co y2 M2 1-x2-y2 (OH)2, where 0 < x2 < 1, 0 < y2 < 1, and x2 + y2 < 1; M2 includes at least one of the elements Mn, Al, Mg, Zr, W, Mo, Ti, Nb, Te, and Sb; The positive electrode material precursor is a spherical particle, Dv50 of the positive electrode material precursor is 8 μm to 18 μm, Dv0>3.0 μm, Dv99<30 μm, and Span of the positive electrode material precursor is 0.8 to 1.2, Span=(Dv90-Dv10) / Dv50.

2. The cathode material precursor according to claim 1, characterized in that The positive electrode material precursor also has at least one of the following characteristics: Feature 1: The cathode material precursor has a radial structure; preferably, the outer layer is radial; Feature 2: In the XRD spectrum of the cathode material precursor, the intensity ratio of the (001) diffraction peak to the (101) diffraction peak is 0.80 to 1.10, preferably 0.90 to 1.00; Feature 3: The elements contained in the inner core layer and the outer surface layer are independently non-uniformly distributed; preferably, the non-uniform distribution is a gradient distribution; Feature 4: The inner core layer and the outer surface layer both contain Ni and Co, the concentration of Ni contained in the inner core layer is higher than the concentration of Ni contained in the outer surface layer, and the concentration of Co contained in the inner core layer is lower than the concentration of Co contained in the outer surface layer.

3. A method for preparing a cathode material precursor according to claim 1 or 2, characterized in that: The following steps are involved: A soluble metal salt solution a1, a first alkaline solution, and a first complexing agent are introduced into a first reaction device and subjected to a first precipitation reaction under stirring to obtain a seed slurry; wherein the soluble metal salt solution a1 is obtained by dissolving a Ni source, a Co source, and an M1 source in water at a molar ratio of Ni, Co, and M1 of x1:y1:(1-x1-y1); A soluble metal salt solution a2, a second alkaline solution, a second complexing agent, and at least a portion of the seed slurry overflowing from the first reaction unit are introduced into a second reaction unit, and a second precipitation reaction is performed under stirring to obtain a reaction slurry; wherein the soluble metal salt solution a2 is obtained by dissolving a Ni source, a Co source, and an M2 source in water at a molar ratio of Ni, Co, and M2 of x2:y2:(1-x2-y2); The reaction slurry is continuously overflowed into the particle size classification device for fine powder separation, and large particles reaching the preset particle size and small particle fine powders that do not reach the preset particle size are separated. The slurry containing the large particles is continuously passed into the aging device for aging, and the small particle fine powder is returned to the first reaction device for continued growth.

4. The preparation method according to claim 3, characterized in that The first precipitation reaction comprises at least one of the following conditions: Condition 1: The total concentration of metal elements in the soluble metal salt solution a1 is 1.2 mol / L to 2.5 mol / L; Condition 2: The concentration of the alkali in the first alkaline solution is 30 wt% to 50 wt%, and the first alkaline solution is used to control the pH value of the first precipitation reaction to be 11 to 13; preferably, the first alkaline solution comprises at least one of a NaOH solution and a KOH solution; Condition 3: The first complexing agent is aqueous ammonia with a concentration not exceeding 30 wt %, and the concentration of ammonia in the first reaction device is 0.5 g / L to 10 g / L, preferably 2.5 g / L to 6 g / L; Condition 4: In the first reaction device, the hourly inflow rate of the soluble metal salt solution a1 is 3% to 10% of the total volume of the first reaction device; Condition 5: The temperature of the first precipitation reaction is 40°C to 80°C, preferably 60°C to 75°C; Condition 6: The stirring speed of the first precipitation reaction is 100 rpm to 700 rpm, preferably 300 rpm to 600 rpm; Condition 7: The Dv50 of the seed crystals in the seed crystal slurry is 2 μm to 8 μm.

5. The preparation method according to claim 3, characterized in that The seed slurry continuously overflowing from the first reaction device is first passed into the seed storage device, and then passed from the seed storage device into the second reaction device as needed.

6. The preparation method according to claim 3, characterized in that The second precipitation reaction comprises at least one of the following conditions: Condition 8: The total concentration of metal elements in the soluble metal salt solution a2 is 1.2 mol / L to 2.5 mol / L; Condition 9: The concentration of the alkali in the second alkaline solution is 30 wt% to 50 wt%, and the second alkaline solution is used to control the pH value of the second precipitation reaction to be 9.5 to 12, and the pH value of the second precipitation reaction is lower than the pH value of the first precipitation reaction; preferably, the pH value of the second precipitation reaction is 10 to 11; preferably, the second alkaline solution comprises at least one of a NaOH solution and a KOH solution; Condition 10: The second complexing agent is aqueous ammonia with a concentration not exceeding 30 wt %, and the concentration of ammonia in the second reaction device is 0.5 g / L to 10 g / L, preferably 2.5 g / L to 6 g / L; Condition 11: In the second reaction device, the hourly inflow rate of the soluble metal salt solution a2 is 3% to 10% of the total volume of the second reaction device; Condition 12: In the second reaction device, the flow rate of the seed slurry is 10 L / h to 30 L / h; Condition 13: The temperature of the second precipitation reaction is 40°C to 80°C, preferably 60°C to 75°C; Condition 14: The stirring speed of the second precipitation reaction is 100 rpm to 700 rpm, preferably 300 rpm to 600 rpm.

7. The preparation method according to claim 3, characterized in that The particle size classification device is selected from a tubular centrifuge, a butterfly centrifuge or a horizontal screw centrifuge.

8. The preparation method according to claim 3, characterized in that Also includes: The aged slurry is washed, dehydrated and dried.

9. A positive electrode material, characterized in that The positive electrode material is prepared from the positive electrode material precursor according to claim 1 or 2.

10. A battery, characterized in that: The battery comprises the positive electrode material according to claim 9.

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