Manganese-rich-based positive electrode material precursor and preparation method and application thereof

Abstract

The invention discloses a manganese-rich-based positive electrode material precursor and a preparation method and application thereof, and belongs to the technical field of battery materials. The chemical general formula of the precursor is MnxNiy (OH) 2, x is more than or equal to 0.6 and less than or equal to 0.7, and y is equal to 1-x; the precursor is spherical or sphere-like, the average sphericity degree of particles of the precursor under the multiple of 1K is larger than or equal to 0.96, K90 of the precursor is 0.55-0.65, and K90 is equal to (D90-D10) / D50. The precursor has relatively high sphericity, uniform and full particle distribution and no obvious adhesion trace, is beneficial to improving the sintering consistency and the compaction density of the positive electrode material, and is further beneficial to improving the cycle performance and the energy density of a battery prepared from the positive electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and in particular to a manganese-rich based positive electrode material precursor and a preparation method and application thereof. Background Art

[0002] The rapid development of new energy vehicles has placed higher demands on the energy density and cycle life of lithium-ion batteries, and cathode materials are the core factor determining the performance of lithium-ion batteries. Lithium-rich manganese-based layered oxides (LMLOs) are considered to be the most promising cathode materials for next-generation power batteries due to their advantages such as high specific capacity, high operating voltage, low cost, and high safety. However, high-manganese hydroxides, which serve as precursors for lithium-rich manganese-based cathodes, are prone to agglomeration during the wet precipitation preparation process, resulting in poor sphericity. In the prior art, there are two main approaches to improving the sphericity of precursor particles. One is to add complexing agents and dispersants to the reaction system to reduce the reaction rate and weaken particle agglomeration, thereby inhibiting the disordered agglomeration of manganese-rich precursor particles. However, this method increases the cost of raw materials and the cost of separating and processing organic reagents in the mother liquor and washing liquid. In addition, the prepared precursor particles have coarse whiskers and low tap density, which in turn affects the sintering activity and compaction density of the cathode material. Another approach is to use co-precipitation in a carbonate system combined with the preparation of medium and large particle sizes to improve sphericity. However, the particles prepared by this method have a large particle size and cannot solve the difficult problem of poor sphericity existing in the current mainstream field of small-particle manganese-rich precursors.

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

[0004] The object of the present invention is to provide a manganese-rich based positive electrode material precursor and its preparation method and application, so as to solve or improve the above technical problems.

[0005] The present invention can be achieved like this: In the first aspect, the present invention provides a manganese-rich positive electrode material precursor, the chemical formula of the manganese-rich positive electrode material precursor is Mn x Ni y (OH)2, where 0.6≤x≤0.7, y=1-x; The manganese-rich positive electrode material precursor is spherical or quasi-spherical, and the average sphericity of the particles of the manganese-rich positive electrode material precursor at 1K multiple is ≥0.96; The D of the manganese-rich based cathode material precursor 50 =3μm~4μm, K 90 =0.55~0.65, where K 90 =(D 90 -D 10 ) / D 50 .

[0006] In an optional embodiment, the tap density of the manganese-rich positive electrode material precursor is 1.50 g / cm 3 ~1.71g / cm 3 ; And / or, the specific surface area of ​​the manganese-rich positive electrode material precursor is 20m 2 / g~40m 2 / g.

[0007] In a second aspect, the present invention provides a method for preparing a manganese-rich-based cathode material precursor as described in the aforementioned embodiment, comprising a nucleation stage, a crystal nucleus growth stage, and a crystal seed growth stage; Among them, the average growth rate of the particles in the control nucleus growth stage is 10nm / h~30nm / h; The average growth rate of the seed crystal in the seed crystal growth stage is controlled not to exceed 18 nm / h.

[0008] In an optional embodiment, the nucleation stage includes: adding a mixed salt solution and a sodium hydroxide solution in parallel to a reaction vessel containing a base liquid under a protective gas environment, controlling the reaction temperature to be 40° C. to 50° C., and the reaction time to be 240 min to 360 min; The base liquid includes water, sodium hydroxide solution and ammonia water, the concentration of the sodium hydroxide solution is 310g / L~330g / L, the pH value of the base liquid is 11.95~12.05, and the ammonia value is 2g / L~3g / L; the mixed salt solution is an aqueous solution of soluble nickel salt and soluble manganese salt, and the total concentration of nickel and manganese ions in the mixed salt solution is 120g / L~140g / L; the feeding rate of the mixed salt solution is 0.042mol / h~0.045mol / h, calculated based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel.

[0009] In an optional embodiment, the volume of the base liquid is 40% to 60% of the volume of the reaction container.

[0010] In an optional embodiment, during the nucleation stage, the feed coefficient, i.e., the flow ratio of the sodium hydroxide solution to the mixed salt solution, is 0.61:1 to 0.63:1.

[0011] In an optional embodiment, the crystal nucleus growth stage includes: after the nucleation is completed, the pH value of the solution in the reaction vessel is reduced to 8.0-9.0 by reducing the feeding coefficient; in the crystal nucleus growth stage, the mixed salt solution and the sodium hydroxide solution are continued to be added in parallel at the same flow rate as the nucleation stage for the first 2-3 hours, and the protective gas is kept at the same flow rate as the nucleation stage; after the reaction for 2-3 hours, the flow rate of the mixed salt solution and the sodium hydroxide solution is increased by a gradient upflow method, and the stirring speed in the crystal nucleus growth stage is controlled so that the particle size reaches D 50The reaction time is 30h~36h until the particle size D is 1.5μm~1.7μm. 50 The precursor seed crystal size is 1.9μm~2.1μm; The flow rate was increased by a gradient upflow method based on the total molar number of nickel and manganese ions in the metal salt solution per liter of the reaction vessel. The upflow time was 6h~8h, and the feed flow rate of the mixed salt solution was increased to 0.126mol / h~0.135mol / h. The stirring speed in the crystal nucleus growth stage was controlled so that the particle size reached D 50 The reaction time for particles of 1.9μm~2.1μm is 70h~80h.

[0012] In an optional embodiment, during the crystal nucleus growth stage, the flow ratio of the sodium hydroxide solution to the mixed salt solution is 0.55:1 to 0.57:1.

[0013] In an optional embodiment, the seed crystal growth stage includes: feeding the material in a gradient rising flow manner and ultimately maintaining a stable flow rate; while feeding the material, introducing a protective gas at the same flow rate as in the crystal nucleus growth stage and maintaining the total gas flow rate stable until the precursor seed crystal grows to a preset particle size, thereby obtaining a manganese-rich positive electrode material precursor; The initial feed flow rate is 0.042 mol / L~0.045 mol / L based on the total molar number of nickel and manganese ions in the mixed salt solution per liter of reaction vessel. After 1h~2h of reaction, the flow rate is increased by gradient rising method. The rising time is 6h~8h, and the feed flow rate of the mixed salt solution is increased to 0.126 mol / h~0.135 mol / h. The stirring speed in the seed crystal growth stage is controlled so that the seed crystal grows to D 50 The reaction time for particles of 3.0μm~4.0μm is not less than 60h.

[0014] In an optional embodiment, the seed growth stage has at least one of the following characteristics: Feature 1: Before the seed crystal growth reaction, adjust the solid content in the reaction vessel to 200g / L~250g / L; Feature 2: The flow ratio of the sodium hydroxide solution to the mixed salt solution is 0.55:1 to 0.57:1; Feature 3: The pH value corresponding to the seed crystal growth stage is 8.0~9.0; Feature 4: The reaction temperature during the seed crystal growth stage is 30°C~40°C.

[0015] In an optional embodiment, during the entire process of preparing the manganese-rich-based positive electrode material precursor, the ratio of the total volume of the protective gas and air introduced per hour to the volume of the reaction container is 1.0-1.2.

[0016] In a third aspect, the present invention provides a manganese-rich-based positive electrode material, wherein the raw materials for preparing the manganese-rich-based positive electrode material include the manganese-rich-based positive electrode material precursor of the aforementioned embodiment.

[0017] In a fourth aspect, the present invention provides a battery, wherein the raw materials for preparing the battery include the manganese-rich-based positive electrode material of the aforementioned embodiment.

[0018] The beneficial effects of the present invention include: The present invention adopts a two-step method to prepare small particle size (D 50 =3μm-4μm) manganese-rich precursor. A manganese-rich precursor with high sphericity, uniform and full particle distribution, and no obvious cracks was prepared through a process design that adds ammonia to the base liquid. Furthermore, the low temperature and low pH process conditions used during the preparation process alleviated the problems of coarse whiskers and loose particle structure caused by ammonia. The manganese-rich precursor prepared by this invention improves the sintering consistency and compaction density of the positive electrode material, promotes lithium ion diffusion, and further enhances the cycling performance and energy density of batteries prepared from this positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 This is an SEM image of the manganese-rich positive electrode material precursor prepared in Example 1 of the present invention, wherein (b) is a partial enlarged view of (a); Figure 2 This is an SEM image of the manganese-rich positive electrode material precursor prepared in Example 2 of the present invention, wherein (b) is a partial enlarged view of (a); Figure 3 This is an SEM image of the manganese-rich positive electrode material precursor prepared in Comparative Example 1 of the present invention, wherein (b) is a partial enlarged view of (a); Figure 4 This is an SEM image of the manganese-rich positive electrode material precursor prepared in Comparative Example 2 of the present invention, wherein (b) is a partial enlarged view of (a); Figure 5 This is an SEM image of the manganese-rich positive electrode material precursor prepared in Comparative Example 3 of the present invention, wherein (b) is a partial enlarged view of (a); Figure 6 This is a graph showing the average sphericity test results of the manganese-rich based positive electrode material precursor prepared in Example 2 of the present invention; Figure 7 This is a graph showing the average sphericity of the manganese-rich positive electrode material precursor prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0022] The following describes in detail the manganese-rich-based cathode material precursor provided by the present invention, its preparation method, and its application.

[0023] The present invention provides a manganese-rich positive electrode material precursor, the chemical formula of which is Mn x Ni y (OH)2, 0.6≤x≤0.7, y=1-x.

[0024] The manganese-rich-based positive electrode material precursor is spherical or quasi-spherical, and the average sphericity of the particles is ≥0.96 at a 1K multiple.

[0025] The K of the manganese-rich cathode material precursor 90 =0.55~0.65, K 90 =(D 90 -D 10 ) / D 50 In some optional embodiments, the D of the manganese-rich positive electrode material precursor 50 3.0μm~4.0μm, further D 50 In some optional embodiments, the D of the manganese-rich positive electrode material precursor is 90 4.9μm~5.8μm, further D 90 It can be 4.82μm~5.12μm.

[0026] The manganese-rich precursor of the positive electrode material with the above characteristics has high sphericity, uniform and full particle distribution, and no obvious adhesion marks. The low temperature and low pH process conditions used during the preparation process also optimize the problems of coarse whiskers and loose particle structure caused by ammonia. The manganese-rich precursor prepared by the present invention is beneficial for improving the sintering consistency and compaction density of the positive electrode material, promoting lithium ion diffusion, and further contributing to the improvement of the cycle performance and energy density of the battery prepared from the above positive electrode material.

[0027] Furthermore, the tap density of the manganese-rich positive electrode material precursor provided by the invention is 1.50 g / cm 3~1.71g / cm 3 , with a specific surface area of ​​20m 2 / g~40m 2 / g.

[0028] Accordingly, the present invention also provides a method for preparing the above-mentioned manganese-rich-based positive electrode material precursor, comprising a nucleation stage, a crystal nucleus growth stage, and a crystal seed growth stage; The average growth rate of the crystal nucleus growth stage is controlled to be 10 nm / h to 30 nm / h, and the average growth rate of the crystal seeds in the crystal seed growth stage is controlled to be no more than 18 nm / h.

[0029] In some embodiments, the stirring speed during the crystal nucleus growth stage can be controlled so that the average growth rate of the particles is 10 nm / h to 30 nm / h; similarly, the stirring speed during the seed crystal growth stage can be controlled so that the average growth rate of the seed crystal does not exceed 18 nm / h.

[0030] The following is a detailed introduction to each stage: S1: Nucleation stage.

[0031] Under a protective gas environment, a mixed salt solution and a sodium hydroxide solution are added in parallel to a reaction vessel containing a bottom liquid, the reaction temperature is controlled at 40° C. to 50° C., and the reaction time is controlled at 240 min to 360 min.

[0032] The base liquid includes water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution can be 310 g / L to 330 g / L, such as 310 g / L, 315 g / L, 320 g / L, 325 g / L, or 330 g / L, or other values ​​within the range of 310 g / L to 330 g / L.

[0033] The pH value of the base solution may be 11.95-12.05, such as 11.95, 11.98, 12.00, 12.02 or 12.05, or other values ​​within the range of 11.95-12.05.

[0034] The volume of the base liquid may be 40% to 60% of the volume of the reaction container, such as 40%, 45%, 50%, 55% or 60%, etc., or may be other values ​​within the range of 40% to 60%.

[0035] The ammonia value of the base solution can be 2g / L~3g / L, such as 2g / L, 2.5g / L or 3g / L, or other values ​​within the range of 2g / L~3g / L.

[0036] The mixed salt solution is an aqueous solution of a soluble nickel salt and a soluble manganese salt. The total concentration of nickel and manganese ions in the mixed salt solution is 120 g / L to 140 g / L. The molar ratio of Mn to Ni in the mixed salt solution is x:y (matching the general chemical formula). The soluble nickel salt and soluble manganese salt may be in the form of, for example but not limitation, sulfates, nitrates, and acetates.

[0037] The mixed salt solution is fed at a rate of 0.042 mol / h to 0.045 mol / h, calculated based on the total moles of nickel and manganese ions in the mixed salt solution per liter of the reaction vessel. In other words, for a reaction vessel with a total volume of 10 L, the total amount of nickel and manganese ions fed into the reaction vessel per hour is 10 x 0.042 mol to 10 x 0.045 mol.

[0038] In the above stage, the feed coefficient, i.e., the flow ratio of the sodium hydroxide solution to the mixed salt solution, can be 0.61:1 to 0.63:1, such as 0.61:1, 0.62:1 or 0.63:1, etc., or other values ​​within the range of 0.61:1 to 0.63:1.

[0039] In some optional embodiments, the reaction temperature in the nucleation stage may be 40°C, 43°C, 45°C, 48°C or 50°C, etc., or other values ​​within the range of 40°C to 50°C.

[0040] In some optional embodiments, the reaction time of the nucleation stage can be 240 min, 260 min, 280 min, 300 min, 320 min, 340 min or 360 min, etc., or other values ​​within the range of 240 min to 360 min.

[0041] In some optional embodiments, the stirring speed in the nucleation stage can be 420 rpm to 480 rpm.

[0042] In actual operation, protective gas can be introduced into the reaction vessel in advance to evacuate the air inside the reaction vessel, and protective gas can be continuously introduced during the subsequent reaction to maintain a slightly positive pressure in the reaction vessel. Water, sodium hydroxide solution, and aqueous ammonia are added to the reaction vessel as a base solution, and the pH of the base solution is adjusted. The mixed salt solution and sodium hydroxide solution are added in a co-current manner under stirring to form nuclei.

[0043] It should be noted that the sodium hydroxide solution and the mixed salt solution used in the entire preparation process of the manganese-rich positive electrode material precursor remain consistent and do not change due to different stages. In addition, during the entire preparation process of the manganese-rich positive electrode material precursor, the protective gas flow rate is 1L / h to 1.2L / h, based on the volume of protective gas introduced per liter of reaction vessel. The protective gas can be nitrogen, for example.

[0044] S2: Crystal nucleus growth stage.

[0045] Compared to the nucleation stage, the pH value of the solution in the reaction vessel is lowered to 8.0-9.0 (e.g., 8.0, 8.4, 8.6, 8.8, or 9.0) by reducing the feed coefficient. During the crystal nucleation growth stage, the mixed salt solution and the sodium hydroxide solution are added in parallel at the same flow rate as in the nucleation stage for the first 2-3 hours, and the protective gas is kept flowing at the same flow rate as in the nucleation stage. After 2-3 hours of reaction, the flow rates of the mixed salt solution and the sodium hydroxide solution are increased by a gradient upflow method. The stirring speed during the crystal nucleation growth stage is controlled so that the average growth rate of the particles is 20 nm / h-30 nm / h. Preferably, the stirring speed during the crystal nucleation growth stage is controlled so that the particle size reaches D 50 The reaction time is 30h~36h until the particle size D is 1.5μm~1.7μm. 50 The average growth rate of the above particles refers to the growth rate to the preset radius of the particles (i.e. the preset particle D 50 / 2) the time required, where the particle size is preset D 50 It is 1.5μm~1.7μm.

[0046] In some optional embodiments, the stirring speed during the crystal nucleus growth stage may be 420 rpm to 480 rpm.

[0047] In some embodiments, a gradient upflow method is used to increase the flow rate, based on the total moles of nickel and manganese ions in the mixed salt solution per liter of the reaction vessel, and the feed rate of the mixed salt solution is increased to 0.126 mol / h to 0.135 mol / h, and the upflow time is 6 hours to 8 hours. In this case, the flow ratio of the sodium hydroxide solution to the mixed salt solution can be 0.55:1 to 0.57:1, such as 0.55:1, 0.56:1, or 0.57:1, or other values ​​within the range of 0.55:1 to 0.57:1.

[0048] In the present invention, the stirring speed during the crystal nucleus growth stage is controlled so that the particle size reaches D 50 The reaction time for particles with a particle size of 1.5 μm to 1.7 μm is 30 h to 36 h (e.g., 30 h, 31 h, 32 h, 33 h, 34 h, 35 h, or 36 h). Control the stirring speed during the crystal nucleus growth stage to ensure that the particle size reaches D 50 The reaction time for particles of 1.9 μm to 2.1 μm is 70 h to 80 h, such as 70 h, 72 h, 74 h, 76 h, 78 h or 80 h.

[0049] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0050] S3: Seed crystal growth stage.

[0051] At a lower temperature, a gradient rising flow method is used for feeding and finally a stable large flow rate is maintained. At the same time as the feeding, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0052] In some embodiments, prior to the seed growth reaction, the solids content in the reaction vessel is adjusted to 200 g / L to 250 g / L, such as 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, or 250 g / L, or other values ​​within the range of 200 g / L to 250 g / L. Specifically, this can be accomplished by removing a portion of the precursor seed crystals and diluting the remaining precursor seed crystals with water, for example, until the slurry accounts for 40% to 60% of the reaction vessel by volume.

[0053] In some embodiments, the initial feed rate of the mixed salt solution is 0.042 mol / h to 0.045 mol / h, based on the total moles of nickel and manganese ions in the mixed salt solution per liter of the reaction vessel. After a reaction time of 1 to 2 hours (e.g., 1 hour, 1.5 hours, or 2 hours), the flow rate is increased using a gradient upflow method. After a flow upflow time of 6 to 8 hours (e.g., 6 hours, 7 hours, or 8 hours), the flow rate is increased to 0.126 mol / h to 0.135 mol / h. The flow ratio of the sodium hydroxide solution to the mixed salt solution can also be 0.55:1 to 0.57:1, such as 0.55:1, 0.56:1, 0.57:1, etc., or other values ​​within the range of 0.55:1 to 0.57:1.

[0054] During the seed crystal growth stage, the pH corresponding to the reaction is also 8.0~9.0.

[0055] In the present invention, the stirring speed during the seed crystal growth stage is controlled so that the average growth rate of the seed crystal does not exceed 18 nm / h. Preferably, the stirring speed during the seed crystal growth stage is controlled so that the seed crystal grows to D 50 The reaction time for the seed crystal to be 3.0 μm to 4.0 μm is not less than 60 hours, such as 62 hours, 66 hours, 70 hours or 74 hours. The average growth rate of the seed crystal refers to the growth rate to the preset radius of the seed crystal (i.e., the preset D 50 / 2) the time required, where the seed crystal is preset D 50 3.0μm~4.0μm.

[0056] In some optional embodiments, the reaction temperature during the seed crystal growth stage may be 30° C. to 40° C. In some optional embodiments, the stirring speed during the seed crystal growth stage may be 420 rpm to 500 rpm.

[0057] The remaining conditions not described in this stage of the reaction are the same as those in the crystal nucleus growth stage.

[0058] Continuing from the above, the present invention innovatively introduces a low-ammonia seeding process in the preparation of a manganese-rich precursor in a hydrogen-oxygen system, using step-by-step synthesis to control sphericity, morphology, and particle size uniformity. For example, ammonia is added to the nucleation base solution to control the nucleation and growth rates through complexation, preventing excessive nucleation and severe agglomeration. High stirring speeds are also maintained for a certain period to enhance nucleation dispersion. After nucleation, pH and other process parameters are adjusted. When the nuclei reach the target particle size, feeding is stopped to prepare the seed crystals for future use. The seed crystals are then grown further in the reaction vessel at an appropriate solids content. A low-temperature, low-pH process design mitigates the problem of coarse whiskers caused by ammonia. High stirring speeds are used to mitigate particle agglomeration and loose whisker structure. Feeding is stopped when the seed crystals reach the target particle size. High-speed stirring is employed at all stages of the preparation process, effectively increasing the proportion of high speed during the entire growth process, which improves particle dispersion. Furthermore, the step-by-step synthesis extends the total growth time compared to conventional methods (e.g., by a factor of 2), effectively repairing any adhesion cracks in the particles.

[0059] The present invention utilizes a two-step synthesis process to produce seed particles with excellent sphericity using low-ammonia, high-speed conditions. Low temperature and low pH conditions are used during the seed growth phase to mitigate the problem of coarse whiskers. This process also extends the total growth time of small-sized particles and repairs surface adhesion grooves, resulting in a manganese-rich precursor with excellent sphericity, plump particles, no obvious adhesion marks, uniform particle size distribution, and fine, short whiskers.

[0060] In addition, the present invention also provides a lithium-rich manganese-based positive electrode material, and the raw materials for preparing the lithium-rich manganese-based positive electrode material include the above-mentioned manganese-rich positive electrode material precursor.

[0061] Furthermore, the present invention also provides a battery, the raw materials for preparing the battery include the above-mentioned lithium-rich manganese-based positive electrode material to obtain better electrochemical performance.

[0062] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0063] Example 1 This embodiment provides a manganese-rich positive electrode material precursor, the general chemical formula of which is Mn 0.66 Ni 0.34 (OH)2, the preparation method thereof comprises: S1: Nucleation stage.

[0064] S11: Nitrogen was introduced into the reactor (500 L volume) in advance to evacuate the air from the reactor. This was continued throughout the reaction to maintain a slightly positive pressure within the reactor. The ratio of nitrogen introduced per hour to the volume of the reactor vessel was 1.0, and the nitrogen flow rate was 500 L / h.

[0065] S12: Add a bottom liquid to the reactor. The bottom liquid consists of water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution is 320 g / L, the pH value of the bottom liquid is 12, the ammonia content of the bottom liquid is 2.4 g / L, and the volume of the bottom liquid is 55% of the volume of the reaction vessel.

[0066] S13: A mixed salt solution and a sodium hydroxide solution were added concurrently under stirring (at a stirring speed of 480 rpm). The reaction temperature was controlled at 40°C and the reaction time was 240 min. The mixed salt solution was an aqueous solution of nickel sulfate and manganese sulfate. The total concentration of nickel and manganese ions in the mixed salt solution was 133.3 g / L, and the molar ratio of Mn to Ni was 66:34 (matching the general chemical formula). The mixed salt solution was fed at a rate of 0.043 mol / h, calculated as the total moles of nickel and manganese ions per liter of reaction vessel. The flow ratio of sodium hydroxide solution to the mixed salt solution was 0.62:1. The pH was maintained at 12 ± 0.05 during nucleation.

[0067] S2: Crystal nucleus growth stage.

[0068] Compared with the nucleation stage, the pH value was quickly reduced to 8.9±0.05 by adjusting the feed coefficient, and the mixed salt solution and sodium hydroxide solution were added in parallel at the same flow rate as in the nucleation stage, and the protective gas was kept at the same flow rate as in the nucleation stage; after 2 hours of reaction, the flow rates of the mixed salt solution and sodium hydroxide solution were increased by gradient upflow, and the upflow time was 6 hours. The feed rate of the mixed salt solution was increased to 0.129 mol / h and basically maintained stable until the particle size D 50 The precursor seed crystal is 2.0 μm.

[0069] The flow rate ratio of sodium hydroxide solution to mixed salt solution is 0.56:1. In this stage, the stirring speed is 480 rpm. In this stage, the stirring speed makes the particle size D 50 The reaction time to reach 1.5 μm is 34 h, and the particle size D 50 The reaction time to reach 2.0 μm is 76 h.

[0070] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0071] S3: Seed crystal growth stage.

[0072] S31: Transfer out part of the precursor seed crystals and dilute the remaining precursor seed crystals with water until the volume of the slurry accounts for 50% of the reaction container, so that the solid content in the reactor is 220 g / L.

[0073] S32: A gradient rising flow method is used to feed the material and eventually a stable large flow rate is maintained. A lower temperature is used for feeding the material. While feeding the material, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0074] Among them, the temperature of the seed crystal growth stage is 31℃±0.5℃. Based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel, the initial feed flow rate is 0.043mol / h. After 1h of reaction, the flow rate is increased by gradient upflow. The upflow time is 6h, and the feed flow rate of the mixed salt solution is increased to 0.129mol / h. The flow ratio of sodium hydroxide solution to mixed salt solution is also 0.56:1. In this stage, the reaction pH value is 8.9±0.05, the stirring speed is 460rpm, and the precursor seed crystal grows to D 50 The reaction time corresponding to 3.51 μm is 74 h.

[0075] Example 2 This embodiment provides a manganese-rich positive electrode material precursor, the general chemical formula of which is Mn 0.66 Ni 0.34 (OH)2, the preparation method thereof comprises: S1: Nucleation stage.

[0076] S11: Nitrogen was introduced into the reactor (500 L volume) in advance to evacuate the air from the reactor. This was continued throughout the reaction to maintain a slightly positive pressure within the reactor. The ratio of nitrogen introduced per hour to the volume of the reactor vessel was 1.0, and the nitrogen flow rate was 500 L / h.

[0077] S12: Add a bottom liquid to the reactor. The bottom liquid consists of water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution is 320 g / L, the pH value of the bottom liquid is 12, the ammonia content of the bottom liquid is 2.4 g / L, and the volume of the bottom liquid is 55% of the volume of the reaction vessel.

[0078] S13: A mixed salt solution and a sodium hydroxide solution were added concurrently with stirring (at a stirring speed of 480 rpm). The reaction temperature was controlled at 50°C and the reaction time was 360 min. The mixed salt solution was an aqueous solution of nickel sulfate and manganese sulfate. The total concentration of nickel and manganese ions in the mixed salt solution was 133.3 g / L, and the molar ratio of Mn to Ni was 66:34 (matching the general chemical formula). The mixed salt solution was fed at a rate of 0.043 mol / h, calculated as the total moles of nickel and manganese ions per liter of reaction vessel. The flow ratio of sodium hydroxide solution to the mixed salt solution was 0.62:1. The pH was maintained at 12 ± 0.05 during nucleation.

[0079] S2: Crystal nucleus growth stage.

[0080] Compared with the nucleation stage, the pH value was quickly reduced to 8.1±0.05 by adjusting the feed coefficient, and the mixed salt solution and sodium hydroxide solution were added in parallel at the same flow rate as in the nucleation stage, and the protective gas was kept at the same flow rate as in the nucleation stage; after 2 hours of reaction, the flow rates of the mixed salt solution and sodium hydroxide solution were increased by gradient upflow, and the upflow time was 6 hours. The feed rate of the mixed salt solution was increased to 0.129 mol / h and basically maintained stable until the particle size D 50 The precursor seed crystal is 2.0 μm.

[0081] The flow rate ratio of sodium hydroxide solution to mixed salt solution is 0.56:1. In this stage, the stirring speed is 480 rpm. In this stage, the stirring speed makes the particle size D 50 The reaction time to reach 1.7 μm is 34 h, and the particle size D 50 The reaction time to reach 2.0 μm is 76 h.

[0082] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0083] S3: Seed crystal growth stage.

[0084] S31: Transfer out part of the precursor seed crystals and dilute the remaining precursor seed crystals with water until the volume of the slurry accounts for 50% of the reaction container, so that the solid content in the reactor is 220 g / L.

[0085] S32: A gradient rising flow method is used to feed the material and eventually a stable large flow rate is maintained. A lower temperature is used for feeding the material. While feeding the material, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0086] Among them, the temperature of the seed crystal growth stage is 39℃±0.5℃. Based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel, the initial feed flow rate is 0.043mol / h. After 1h of reaction, the flow rate is increased by gradient upflow. The upflow time is 6h, and the feed flow rate of the mixed salt solution is increased to 0.129mol / h. The flow ratio of sodium hydroxide solution to mixed salt solution is also 0.56:1. In this stage, the reaction pH value is 8.1±0.05, the stirring speed is 460rpm, and the precursor seed crystal grows to D 50 The reaction time corresponding to 3.83 μm is 76 h.

[0087] Example 3 This embodiment provides a manganese-rich positive electrode material precursor, the general chemical formula of which is Mn 0.66 Ni 0.34 (OH)2, the preparation method thereof comprises: S1: Nucleation stage.

[0088] S11: Nitrogen was introduced into the reactor (500 L volume) in advance to evacuate the air from the reactor. This was continued throughout the reaction to maintain a slightly positive pressure within the reactor. The ratio of nitrogen introduced per hour to the volume of the reactor vessel was 1.0, and the nitrogen flow rate was 500 L / h.

[0089] S12: Add a bottom liquid to the reactor. The bottom liquid consists of water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution is 320 g / L, the pH value of the bottom liquid is 12, the ammonia content of the bottom liquid is 2.4 g / L, and the volume of the bottom liquid is 55% of the volume of the reaction vessel.

[0090] S13: A mixed salt solution and a sodium hydroxide solution were added concurrently under stirring (at a stirring speed of 480 rpm). The reaction temperature was controlled at 60°C and the reaction time was 360 min. The mixed salt solution was an aqueous solution of nickel sulfate and manganese sulfate. The total concentration of nickel and manganese ions in the mixed salt solution was 133.3 g / L, and the molar ratio of Mn to Ni was 66:34 (matching the general chemical formula). The mixed salt solution was fed at a rate of 0.043 mol / h, calculated as the total moles of nickel and manganese ions per liter of reaction vessel. The flow ratio of sodium hydroxide solution to the mixed salt solution was 0.62:1. The pH was maintained at 12 ± 0.05 during nucleation.

[0091] S2: Crystal nucleus growth stage.

[0092] Compared with the nucleation stage, the pH value was quickly reduced to 8.1±0.05 by adjusting the feed coefficient, and the mixed salt solution and sodium hydroxide solution were added in parallel at the same flow rate as in the nucleation stage, and the protective gas was kept at the same flow rate as in the nucleation stage; after 2 hours of reaction, the flow rates of the mixed salt solution and sodium hydroxide solution were increased by gradient upflow, and the upflow time was 6 hours. The feed rate of the mixed salt solution was increased to 0.129 mol / h and basically maintained stable until the particle size D 50 The precursor seed crystal is 2.0 μm.

[0093] The flow rate ratio of sodium hydroxide solution to mixed salt solution is 0.56:1. In this stage, the stirring speed is 480 rpm. In this stage, the stirring speed makes the particle size D 50 The reaction time to reach 1.7 μm is 34 h, and the particle size D 50 The reaction time to reach 2.0 μm is 76 h.

[0094] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0095] S3: Seed crystal growth stage.

[0096] S31: Transfer out part of the precursor seed crystals and dilute the remaining precursor seed crystals with water until the volume of the slurry accounts for 50% of the reaction container, so that the solid content in the reactor is 220 g / L.

[0097] S32: A gradient rising flow method is used to feed the material and eventually a stable large flow rate is maintained. A lower temperature is used for feeding the material. While feeding the material, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0098] Among them, the temperature of the seed crystal growth stage is 50℃±0.5℃. Based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel, the initial feed flow rate is 0.043mol / h. After 1h of reaction, the flow rate is increased by gradient upflow. The upflow time is 6h, and the feed flow rate of the mixed salt solution is increased to 0.129mol / h. The flow ratio of sodium hydroxide solution to mixed salt solution is also 0.56:1. In this stage, the reaction pH value is 8.1±0.05, the stirring speed is 460rpm, and the precursor seed crystal grows to D 50 The reaction time corresponding to 3.76 μm is 78 h.

[0099] Example 4 This embodiment provides a manganese-rich positive electrode material precursor, the general chemical formula of which is Mn 0.66 Ni 0.34(OH)2, the preparation method thereof comprises: S1: Nucleation stage.

[0100] S11: Nitrogen was introduced into the reactor (500 L volume) in advance to evacuate the air from the reactor. This was continued throughout the reaction to maintain a slightly positive pressure within the reactor. The ratio of nitrogen introduced per hour to the volume of the reactor vessel was 1.0, and the nitrogen flow rate was 500 L / h.

[0101] S12: Add a bottom liquid to the reactor. The bottom liquid consists of water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution is 320 g / L, the pH value of the bottom liquid is 12, the ammonia content of the bottom liquid is 2.4 g / L, and the volume of the bottom liquid is 55% of the volume of the reaction vessel.

[0102] S13: A mixed salt solution and a sodium hydroxide solution were added concurrently with stirring (at a stirring speed of 420 rpm). The reaction temperature was controlled at 50°C and the reaction time was 360 min. The mixed salt solution was an aqueous solution of nickel sulfate and manganese sulfate. The total concentration of nickel and manganese ions in the mixed salt solution was 133.3 g / L, and the molar ratio of Mn to Ni was 66:34 (matching the general chemical formula). The mixed salt solution was fed at a rate of 0.043 mol / h, calculated as the total moles of nickel and manganese ions per liter of reaction vessel. The flow ratio of sodium hydroxide solution to the mixed salt solution was 0.62:1. The pH was maintained at 12 ± 0.05 during nucleation.

[0103] S2: Crystal nucleus growth stage.

[0104] Compared with the nucleation stage, the pH value was quickly reduced to 8.1±0.05 by adjusting the feed coefficient, and the mixed salt solution and sodium hydroxide solution were added in parallel at the same flow rate as in the nucleation stage, and the protective gas was kept at the same flow rate as in the nucleation stage; after 2 hours of reaction, the flow rates of the mixed salt solution and sodium hydroxide solution were increased by gradient upflow, and the upflow time was 6 hours. The feed rate of the mixed salt solution was increased to 0.129 mol / h and basically maintained stable until the particle size D 50 The precursor seed crystal is 2.0 μm.

[0105] The flow rate ratio of sodium hydroxide solution to mixed salt solution is 0.56:1. In this stage, the stirring speed is 480 rpm. In this stage, the stirring speed makes the particle size D 50 The reaction time to reach 1.7 μm is 34 h, and the particle size D 50 The reaction time to reach 2.0 μm is 76 h.

[0106] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0107] S3: Seed crystal growth stage.

[0108] S31: Transfer out part of the precursor seed crystals and dilute the remaining precursor seed crystals with water until the volume of the slurry accounts for 50% of the reaction container, so that the solid content in the reactor is 220 g / L.

[0109] S32: A gradient rising flow method is used to feed the material and eventually a stable large flow rate is maintained. A lower temperature is used for feeding the material. While feeding the material, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0110] Among them, the temperature of the seed crystal growth stage is 39℃±0.5℃. Based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel, the initial feed flow rate is 0.043mol / h. After 1h of reaction, the flow rate is increased by gradient upflow. The upflow time is 6h, and the feed flow rate of the mixed salt solution is increased to 0.129mol / h. The flow ratio of sodium hydroxide solution to mixed salt solution is also 0.56:1. In this stage, the reaction pH value is 8.1±0.05, the stirring speed is 460rpm, and the precursor seed crystal grows to D 50 The reaction time corresponding to 3.84 μm is 70 h.

[0111] Example 5 This embodiment provides a manganese-rich positive electrode material precursor, the general chemical formula of which is Mn 0.66 Ni 0.34 (OH)2, the preparation method thereof comprises: S1: Nucleation stage.

[0112] S11: Nitrogen was introduced into the reactor (500 L volume) in advance to evacuate the air from the reactor. This was continued throughout the reaction to maintain a slightly positive pressure within the reactor. The ratio of nitrogen introduced per hour to the volume of the reactor vessel was 1.0, and the nitrogen flow rate was 500 L / h.

[0113] S12: Add a bottom liquid to the reactor. The bottom liquid consists of water, sodium hydroxide solution, and aqueous ammonia. The concentration of the sodium hydroxide solution is 320 g / L, the pH value of the bottom liquid is 12, the ammonia content of the bottom liquid is 2.4 g / L, and the volume of the bottom liquid is 55% of the volume of the reaction vessel.

[0114] S13: A mixed salt solution and a sodium hydroxide solution were added concurrently with stirring (at a stirring speed of 480 rpm). The reaction temperature was controlled at 50°C and the reaction time was 360 min. The mixed salt solution was an aqueous solution of nickel sulfate and manganese sulfate. The total concentration of nickel and manganese ions in the mixed salt solution was 133.3 g / L, and the molar ratio of Mn to Ni was 66:34 (matching the general chemical formula). The mixed salt solution was fed at a rate of 0.043 mol / h, calculated as the total moles of nickel and manganese ions per liter of reaction vessel. The flow ratio of sodium hydroxide solution to the mixed salt solution was 0.62:1. The pH was maintained at 12 ± 0.05 during nucleation.

[0115] S2: Crystal nucleus growth stage.

[0116] Compared with the nucleation stage, the pH value was quickly reduced to 10±0.05 by adjusting the feed coefficient, and the mixed salt solution and sodium hydroxide solution were added in parallel at the same flow rate as in the nucleation stage, and the protective gas was kept at the same flow rate as in the nucleation stage; after 2 hours of reaction, the flow rates of the mixed salt solution and sodium hydroxide solution were increased by gradient upflow, and the upflow time was 6 hours. The feed rate of the mixed salt solution was increased to 0.129 mol / h and basically maintained stable until the particle size D 50 The precursor seed crystal is 2.0 μm.

[0117] The flow rate ratio of sodium hydroxide solution to mixed salt solution is 0.56:1. In this stage, the stirring speed is 480 rpm. In this stage, the stirring speed makes the particle size D 50 The reaction time to reach 1.7 μm is 34 h, and the particle size D 50 The reaction time to reach 2.0 μm is 76 h.

[0118] The other conditions not specified, such as the reaction temperature in this stage, are the same as those in the nucleation stage.

[0119] S3: Seed crystal growth stage.

[0120] S31: Transfer out part of the precursor seed crystals and dilute the remaining precursor seed crystals with water until the volume of the slurry accounts for 50% of the reaction container, so that the solid content in the reactor is 220 g / L.

[0121] S32: A gradient rising flow method is used to feed the material and eventually a stable large flow rate is maintained. A lower temperature is used for feeding the material. While feeding the material, a protective gas with the same flow rate as that in the crystal nucleus growth stage is introduced and basically kept stable until the precursor seed crystal grows to a preset particle size to obtain a manganese-rich based positive electrode material precursor.

[0122] Among them, the temperature of the seed crystal growth stage is 39℃±0.5℃. Based on the total molar number of nickel and manganese ions in the mixed salt solution corresponding to each liter of reaction vessel, the initial feed flow rate is 0.043mol / h. After 1h of reaction, the flow rate is increased by gradient upflow. The upflow time is 6h, and the feed flow rate of the mixed salt solution is increased to 0.129mol / h. The flow ratio of sodium hydroxide solution to mixed salt solution is also 0.56:1. In this stage, the reaction pH value is 10±0.05, the stirring speed is 460rpm, and the precursor seed crystal grows to D 50 The reaction time corresponding to 3.85 μm is 86 h.

[0123] Comparative Example 1 This comparative example is basically the same as Example 2, the main difference being that in this comparative example, no ammonia water is added to the base liquid.

[0124] Comparative Example 2 This comparative example is basically the same as Example 2, the main difference being that in this comparative example, the stirring speed in both the nucleation stage and the crystal nucleus growth stage is 400 rpm.

[0125] Comparative Example 3 This comparative example is basically the same as Example 2, with the main difference being that in this comparative example, ammonia water is continuously added during the crystal nucleus growth and seed crystal growth stages, and the ammonia value is regulated to be 2.5 g / L±0.5 g / L.

[0126] Test Example 1 ① Taking the manganese-rich positive electrode material precursors obtained in Examples 1-2 and Comparative Examples 1-3 as examples, the surfaces were observed by SEM, and the results were as follows: Figures 1 to 5 shown.

[0127] Among them, Figure 2 and Figure 3 It can be seen that the manganese-rich positive electrode material precursor particles prepared in Example 2 have better sphericity and are fuller, and the adhesion marks are repaired more completely.

[0128] Depend on Figure 2 and Figure 5 It can be seen that the manganese-rich positive electrode material precursor particle whiskers prepared in Example 2 are thinner, shorter and denser, while the particle whiskers of Comparative Example 3 are coarse and have a loose structure because ammonia water is added during the entire synthesis process.

[0129] ② Taking the manganese-rich positive electrode material precursors obtained in Example 2 and Comparative Example 1 as examples, the average sphericity (1K multiple) thereof was compared. The results are as follows: Figure 6 and Figure 7 shown.

[0130] Depend on Figure 6 and Figure 7It can be seen that the average sphericity of the manganese-rich based positive electrode material precursor particles prepared in Example 2 is about 0.98, while the average sphericity of the manganese-rich based positive electrode material precursor particles prepared in Comparative Example 1 is about 0.91. In other words, the manganese-rich based positive electrode material precursor particles prepared in Example 2 have a better average sphericity and better particle dispersibility.

[0131] ③ The performance of the manganese-rich positive electrode material precursors prepared in Examples 1 to 5, Comparative Examples 1 to 3, and the control group was tested.

[0132] Among them, the sphericity of the particles was tested using AVIZO software. 50 、D 10 and D 90 The test was performed using a Malvern 3000 laser particle size analyzer, the tap density was tested using a tap density analyzer, and the specific surface area was tested using a nitrogen adsorption specific surface area analyzer. The results are shown in Table 1.

[0133] Table 1 Test results

[0134] It can be seen from Table 1 that the manganese-rich based positive electrode material precursor prepared by the method provided in this application has a small particle size and is evenly distributed, and has a high average sphericity.

[0135] Test Example 2 The manganese-rich positive electrode material precursors prepared in Examples 1 to 5, Comparative Examples 1 to 3, and the control group were all prepared into positive electrode materials and further prepared into batteries according to the following method: Preparation method of positive electrode material: The manganese-rich precursor material and lithium carbonate are evenly mixed in a ratio of n(Li) / [n(Ni)+n(Mn)]=1.3 and placed in a sintering furnace. The temperature is gradually increased to 600°C in an air atmosphere and kept warm for 2 hours, then continued to be increased to 800°C and kept warm for 8 hours. After cooling naturally, the mixture is taken out, crushed and sieved to obtain a lithium-rich manganese-based positive electrode material.

[0136] Battery preparation method: The lithium-rich manganese-based positive electrode material is mixed with acetylene black, a binder (PVDF), and an organic solvent (NMP) in a ratio of 90:5:5 to prepare a positive electrode slurry. After coating, drying, and cutting, the slurry is assembled into button cells in a glove box. The battery test voltage range is 2.5V~4.6V.

[0137] The test results are shown in Table 2.

[0138] Table 2 Test results

[0139] It can be seen from Table 2 that the manganese-rich based positive electrode material precursor prepared by the method provided in this application can be further prepared into a battery with better electrochemical performance.

[0140] In summary, the solution provided by the present invention has at least the following advantages: (1) The present invention adopts a seed crystal process and a step-by-step synthesis to indirectly prolong the total growth time of the particles, thereby prolonging the repair time of the particle adhesion cracks, so that the particle adhesion cracks can be fully repaired and the obtained particles have a full morphology; (2) Under the step-by-step synthesis scheme, in order to ensure that the seed crystal preparation can be maintained for a long time, the number of crystal nuclei is increased by prolonging the nucleation time. At the same time, ammonia water is added to the bottom liquid and the stirring rate is increased to reduce the rapid agglomeration of the crystal nuclei. This ensures that there are enough seed crystals in the reaction vessel and maintains good dispersion, providing seeds with good sphericity for the subsequent inherited growth of particles. (3) In the early stage of the crystal nucleus growth, an upward flow method is used to avoid excessive particle growth and increased adhesion caused by large flow rates; and a lower temperature is used for growth to reduce the adverse effects of whisker coarsening caused by the addition of ammonia water; (4) During the seed growth stage, part of the seed crystals are transferred for growth to ensure that high-speed stirring can be maintained in the early stage of growth. Compared with the non-seed process, the stirring intensity is increased at the same particle size, the adhesion between the particles is weakened, and the particles can maintain a monodisperse growth state to a greater extent. The obtained particles have better sphericity and narrower particle size distribution; (5) The preparation process mainly strengthens particle dispersion by speed control and flow control, and controls particle whiskers by low temperature and low pH process conditions to make them finer; (6) The prepared precursor has a small particle size and high sphericity, the particles are evenly distributed and full, there is no obvious adhesion mark, and the whiskers are short and dense, which is beneficial to improving the sintering consistency and compaction density of the positive electrode material, and further beneficial to improving the cycle performance and energy density of the battery prepared from the above positive electrode material.

[0141] 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 manganese-rich positive electrode material precursor, characterized in that: The chemical formula of the manganese-rich positive electrode material precursor is Mn x Ni y (OH)2, where 0.6≤x≤0.7, y=1-x; The manganese-rich positive electrode material precursor is spherical or quasi-spherical, and the average sphericity of the particles of the manganese-rich positive electrode material precursor at 1K multiple is ≥0.96; The D of the manganese-rich positive electrode material precursor 50 =3μm~4μm, K 90 =0.55~0.65, where K 90 =(D 90 -D 10 ) / D 50 .

2. The manganese-rich-based cathode material precursor according to claim 1, characterized in that The tap density of the manganese-rich positive electrode material precursor is 1.50 g / cm 3 ~1.71g / cm 3 ; And / or, the specific surface area of ​​the manganese-rich positive electrode material precursor is 20m 2 / g~40m 2 / g.

3. A method for preparing a manganese-rich positive electrode material precursor according to claim 1 or 2, characterized in that: It includes the nucleation stage, the crystal nucleus growth stage and the crystal seed growth stage; Among them, the average growth rate of the particles in the control nucleus growth stage is 10nm / h~30nm / h; The average growth rate of the seed crystal in the seed crystal growth stage is controlled not to exceed 18 nm / h.

4. The preparation method according to claim 3, characterized in that The nucleation stage includes: adding a mixed salt solution and a sodium hydroxide solution in parallel to a reaction vessel containing a bottom liquid under a protective gas environment, controlling the reaction temperature to be 40° C. to 50° C., and the reaction time to be 240 min to 360 min; The base liquid comprises water, sodium hydroxide solution, and ammonia water. The concentration of the sodium hydroxide solution is 310 g / L to 330 g / L, the pH value of the base liquid is 11.95 to 12.05, and the ammonia value is 2 g / L to 3 g / L. The mixed salt solution is an aqueous solution of a soluble nickel salt and a soluble manganese salt. The total concentration of nickel and manganese ions in the mixed salt solution is 120 g / L to 140 g / L. The feeding flow rate of the mixed salt solution is 0.042 mol / h to 0.045 mol / h, calculated based on the total molar number of nickel and manganese ions in the mixed salt solution per liter of reaction vessel. Optionally, the volume of the base liquid is 40% to 60% of the volume of the reaction container; Optionally, in the nucleation stage, the feed coefficient, i.e., the flow ratio of the sodium hydroxide solution to the mixed salt solution, is 0.61:1 to 0.63:

1.

5. The preparation method according to claim 4, characterized in that The crystal nucleus growth stage includes: after the nucleation is completed, the pH value of the solution in the reaction vessel is reduced to 8.0-9.0 by reducing the feeding coefficient; in the crystal nucleus growth stage, the mixed salt solution and the sodium hydroxide solution are continued to be added in parallel at the same flow rate as in the nucleation stage for the first 2-3 hours, and the protective gas is kept at the same flow rate as in the nucleation stage; after the reaction for 2-3 hours, the flow rate of the mixed salt solution and the sodium hydroxide solution is increased by a gradient upflow method, and the stirring speed in the crystal nucleus growth stage is controlled to make the particle size reach D 50 The reaction time is 30h~36h until the particle size D is 1.5μm~1.7μm. 50 The precursor seed crystal size is 1.9μm~2.1μm; The flow rate was increased by a gradient upflow method based on the total molar number of nickel and manganese ions in the metal salt solution per liter of reaction vessel. The upflow time was 6h~8h, and the feed flow rate of the mixed salt solution was increased to 0.126mol / h~0.135mol / h. The stirring speed in the crystal nucleus growth stage was controlled to make the particle size reach D 50 The reaction time for 1.9μm~2.1μm is 70h~80h; Optionally, during the crystal nucleus growth stage, the flow ratio of the sodium hydroxide solution to the mixed salt solution is 0.55:1 to 0.57:

1.

6. The preparation method according to claim 5, characterized in that The seed crystal growth stage includes: feeding the material in a gradient rising flow manner and ultimately maintaining a stable flow rate, while feeding the material and simultaneously introducing the protective gas at the same flow rate as in the crystal nucleus growth stage and maintaining it basically stable until the precursor seed crystal grows to a preset particle size, thereby obtaining a manganese-rich positive electrode material precursor; The total molar number of nickel and manganese ions in the mixed salt solution per liter of reaction vessel is calculated. The initial feed flow rate is 0.042 mol / h~0.045 mol / h. After 1h~2h of reaction, the flow rate is increased by a gradient upflow method. The upflow time is 6h~8h, and the feed flow rate of the mixed salt solution is increased to 0.126 mol / h~0.135 mol / h. The stirring speed in the seed crystal growth stage is controlled so that the seed crystal grows to D 50 The reaction time for particles of 3.0μm~4.0μm is not less than 60h.

7. The preparation method according to claim 6, characterized in that The seed growth stage has at least one of the following characteristics: Feature 1: Before the seed crystal growth reaction, adjust the solid content in the reaction vessel to 200g / L~250g / L; Feature 2: The flow ratio of the sodium hydroxide solution to the mixed salt solution is 0.55:1 to 0.57:1; Feature 3: The pH value corresponding to the seed crystal growth stage is 8.0~9.0; Feature 4: The reaction temperature during the seed crystal growth stage is 30°C~40°C.

8. The preparation method according to any one of claims 3 to 7, characterized in that During the entire preparation process of the manganese-rich based cathode material precursor, the volume ratio of the protective gas introduced per hour to the reaction vessel is 1.0-1.

2.

9. A manganese-rich positive electrode material, characterized in that The raw materials for preparing the manganese-rich based positive electrode material include the manganese-rich based positive electrode material precursor according to claim 1 or 2.

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

Images