High-nickel polycrystalline precursor and preparation method thereof

Abstract

The invention provides a high-nickel polycrystalline precursor and a preparation method thereof, and relates to the technical field of lithium battery materials. The chemical formula of the high-nickel polycrystalline precursor is Ni < x > Co < y > Mn < z > M < w > (OH) < 2 >, m comprises at least one of Zr, Ti, V, Mo, Zn, W and Al; 0.80 < = x < = 0.98, 0.02 < = y < = 0.06, 0 < = z < = 0.04, 0 < = w < = 0.01, and x + y + z + w = 1. According to the high-nickel polycrystalline precursor, the capacity, the stability and the conductivity are improved by regulating and controlling the ratio of nickel, cobalt and manganese and introducing trace doping elements, and meanwhile, the crystallinity and the thermal stability are improved. A composite structure with a loose and porous inner core and a compact outer shell enhances a lithium ion transmission channel, activity, capacity performance and high-temperature cycling stability. The inner core layer of the particles is rapidly agglomerated in the nucleating period, the triangular sheet-shaped primary particles of the shell layer are flatly laid and stacked, the outer sheet layer is perpendicular to the pressure direction in the compaction process, the mechanical strength is obviously enhanced, and the density is improved after sintering.

Description

Technical Field

[0001] This invention relates to the field of lithium battery materials technology, and more specifically, to a high-nickel polycrystalline precursor and its preparation method. Background Technology

[0002] Lithium-ion batteries have become the mainstream choice for new energy vehicles, portable electronic devices, and energy storage systems due to their high energy density, long cycle life, and excellent rate performance. In lithium-ion batteries, the cathode material is a key component determining the overall battery performance; its specific capacity, compaction density, and structural stability directly affect the battery's energy density, safety, and cycle life. To meet the demands of high-energy-density batteries, high-nickel ternary cathode materials (such as Ni-Co-Mn oxides with a Ni content ≥80%) have become a research and application hotspot. The performance of high-nickel cathode materials largely depends on the composition, structure, and morphology of their precursors; therefore, developing high-performance high-nickel ternary precursor materials is a fundamental step in achieving high-performance batteries.

[0003] In existing technologies, high-nickel precursors are generally prepared using a co-precipitation method, forming a secondary particle structure composed of primary particles. To improve the structural uniformity and compaction characteristics of the material, some technical solutions employ methods such as adjusting precipitation parameters, adding complexing agents, and segmented alkali control to make the precursor exhibit a spherical morphology or a lamellar particle stacked structure. Some studies have proposed oriented stacking of primary particles on the outer layer, with the inner layer exhibiting a radial or porous structure, aiming to inherit this composite structure after the cathode material is sintered, thereby achieving higher compaction density and mechanical strength. Simultaneously, other methods combine the advantages of continuous and discontinuous methods to obtain precursor materials with high specific capacity and superior cycle stability. These solutions, to some extent, improve the crystallinity and structural stability of the material, providing a foundation for improving battery performance.

[0004] Although some technologies have attempted to optimize the precursor structure design, several technical bottlenecks still exist in high-nickel precursors at present. First, the tap density of precursor materials is generally low, typically not exceeding 2.0 g / cm³, resulting in insufficient compaction density of the cathode material after sintering, thus limiting the electrode's stacking capacity and the overall energy density of the battery. Second, conventional secondary particle structures often employ radial or irregular stacking methods, resulting in loose interparticle bonding. This makes them prone to uneven structural shrinkage during sintering, potentially inducing microcracks or even particle breakage. Third, if the outer layer composed of sheet-like particles lacks directional control during arrangement, slippage or delamination can easily occur, affecting the electrode's mechanical properties and long-term cycle stability.

[0005] In summary, existing high-nickel ternary precursor materials have significant shortcomings in terms of tap density, structural stability, and particle morphology control. On the one hand, low tap density limits the compaction performance of subsequent cathode materials, hindering the achievement of high energy density targets. On the other hand, loose particle structure and disordered arrangement easily lead to mechanical degradation during high-temperature sintering and charge-discharge processes, resulting in material degradation and capacity decay. These technical problems, to some extent, restrict the further promotion and large-scale application of high-nickel cathode materials in high-performance lithium-ion batteries.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this application is to provide a high-nickel polycrystalline precursor and its preparation method. The high-nickel polycrystalline precursor enhances the structural stability and conductivity of the cathode material by adjusting the ratio of Ni, Co and Mn. The introduction of various trace doping elements helps to improve the crystallinity and thermal stability of the precursor.

[0008] In order to achieve the above-mentioned objectives of this application, the following technical solution is adopted: In a first aspect, this application provides a high-nickel polycrystalline precursor, the chemical formula of which is: Ni x Co y Mn z M w (OH)2; Wherein, M includes at least one of Zr, Ti, V, Mo, Zn, W and Al; 0.80≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.04, 0≤w≤0.01; and x+y+z+w=1.

[0009] In a preferred embodiment, the high-nickel polycrystalline precursor is a secondary particle assembled from primary particles and has a composite structure; and / or, the high-nickel polycrystalline precursor is a secondary particle comprising: an inner layer and an outer layer; or, an inner layer, a transition layer, and an outer layer. The inner layer is a porous inner layer, and the density of the inner layer is less than that of the outer layer.

[0010] In a preferred embodiment, the outer layer of the high-nickel polycrystalline precursor is composed of triangular sheet-like primary particles; The triangular pieces are arranged in a flat manner during the sintering and compaction process, and the direction of the pieces is perpendicular to the direction of applied pressure.

[0011] In a preferred embodiment, the triangular sheet has at least one of the following features: A. The side length of the triangle is 500nm~3000nm; B. The thickness of the triangle is 200nm~500nm; C. The number of triangular lamellar layers in the direction of crystal plane (101) is 120~150.

[0012] In a preferred embodiment, the secondary particles have at least one of the following structural features: A. The thickness of the outer layer is greater than the particle size of the inner layer; B. The secondary particles of the high-nickel polycrystalline precursor have a particle size of 10μm~17μm; C. The particle size of the inner layer is 1μm~3μm; D. The thickness of the transition layer is 2μm~7μm; E. The thickness of the outer layer is 7μm~11μm.

[0013] In a preferred embodiment, the crystal form of the high-nickel polycrystalline precursor satisfies at least one of the following crystallinity characteristics: A. The full width at half maximum (FWHM) of the (001) crystal plane is not greater than 0.300°; B. The full width at half maximum (FWHM) of the (101) crystal plane is not greater than 0.300°; C. The crystal deformation stacking fault rate (FD) is 0% to 2%.

[0014] Secondly, this application provides a method for preparing a high-nickel polycrystalline precursor as described in any of the foregoing embodiments, comprising: Prepare a metal salt solution based on the molar ratio of the metal elements in the chemical formula of the high-nickel polycrystalline precursor. The metal salt solution, precipitant solution, and complexing agent solution are mixed to carry out a co-precipitation reaction. After solid-liquid separation and drying, a high-nickel polycrystalline precursor is obtained.

[0015] In a preferred embodiment, the coprecipitation reaction conditions include at least one of the following conditions: A. Reaction temperature: 50℃~70℃; B. pH value 11~12; C. Alkalinity: 15g / L~35g / L; D. Rotation speed 300 r / min ~ 400 r / min; E. The reaction time is 100 to 200 hours; F. The precipitant solution includes NaOH solution; G. The complexing agent solution includes ammonia.

[0016] In a preferred embodiment, the coprecipitation reaction includes: The first stage reaction is carried out under the condition of alkalinity below 5 g / L to obtain the first reaction precipitate slurry. The nucleation of primary particles in the first reaction precipitate slurry is controlled to form a porous inner layer. The second stage reaction is carried out under the condition of alkalinity of 5 g / L to 15 g / L to obtain the second reaction precipitate slurry, so that the primary particles in the second reaction precipitate slurry are transformed from radial to flat stacking, forming a transition layer outside the inner layer; The third stage reaction is carried out under the condition of alkalinity of 15 g / L to 35 g / L to obtain the third reaction precipitation slurry. The primary particles in the third reaction precipitation slurry are induced to form triangular plate-like morphology and be arranged in a flat stack to construct the outer layer outside the transition layer.

[0017] In a preferred embodiment, the first stage reaction includes: using the precipitant solution, the complexing agent solution, and water as the reaction substrate, performing a first mixing treatment with the metal salt solution to obtain a mixed reaction solution; during the first mixing treatment, adjusting the pH of the mixed reaction solution to 11-12 and the alkalinity to 3g / L-5g / L using the precipitant solution and the complexing agent solution, and adjusting the particle size D in the slurry. 50 The reaction is stopped when the particle size of the inner layer reaches 1μm~3μm, yielding the first reaction precipitate slurry; and / or, The second stage reaction includes: during the second mixing process, adjusting the pH of the second reaction precipitate slurry to 11-12 and the alkalinity to 5 g / L-15 g / L using the precipitant solution and the complexing agent solution, and adjusting the particle size D in the slurry. 50 The reaction is stopped when the thickness of the transition layer reaches 2μm~7μm, resulting in the second reaction precipitate slurry; and / or, The third stage reaction includes: during the third mixing treatment, adjusting the pH of the third reaction precipitate slurry to 11-12 and the alkalinity to 15g / L-35g / L using the precipitant solution and the complexing agent solution, and adjusting the particle size D in the slurry. 50 The reaction is stopped when the thickness of the outer layer reaches 7μm~11μm, and the third reaction precipitate slurry is obtained.

[0018] In a preferred embodiment, the reaction conditions for the first stage reaction include: a reaction temperature of 60°C to 65°C; and / or, the first mixing treatment is stirring mixing at a rotation speed of 50 r / min to 400 r / min; and / or The reaction conditions for the second stage reaction include: a reaction temperature of 60℃~65℃; and / or, the second mixing treatment is stirring at a speed of 50r / min~400r / min; and / or, The reaction conditions for the third stage reaction include: a reaction temperature of 60℃~65℃; and / or, the second mixing treatment is stirring mixing at a speed of 50r / min~400r / min.

[0019] Thirdly, this application provides a cathode material, which is prepared from the high-nickel polycrystalline precursor as described in the foregoing embodiments, or from the high-nickel polycrystalline precursor obtained by the preparation method of the high-nickel polycrystalline precursor as described in the foregoing embodiments.

[0020] Fourthly, this application provides an electrode sheet comprising the positive electrode material as described in the foregoing embodiments.

[0021] Fifthly, this application provides a battery including the electrode as described in the foregoing embodiments.

[0022] Sixthly, this application provides an electrical device including a battery as described in the foregoing embodiments.

[0023] This application provides a high-nickel polycrystalline precursor and its preparation method. The high-nickel polycrystalline precursor is prepared by setting the chemical formula to Ni. x Co y Mn z M w (OH)2; the Ni content is 0.80-0.98%, ensuring a high nickel ratio in the material, which is beneficial to improving the specific capacity and energy density of the cathode material after lithiation. At the same time, the appropriate introduction of Co (0.02≤y≤0.06) and Mn (0≤z≤0.04) can improve the structural stability and electronic conductivity of the material while maintaining high capacity, and suppress capacity decay during cycling. Furthermore, by introducing at least one metal element from Zr, Ti, V, Mo, Zn, W and Al as a trace dopant (0≤w≤0.01), the crystallinity and thermal stability of the precursor are improved without destroying the crystal structure, and the phase stability during high-temperature sintering is enhanced. In addition, limiting x+y+z+w=1 helps to achieve balanced control of the metal molar ratio, improve the uniformity of the precursor composition distribution and the repeatability of the preparation process, thereby improving the overall performance stability and industrial adaptability of the precursor material. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a cross-sectional view of the high-nickel polycrystalline precursor prepared in Example 1 of this application; Figure 2 This is a SEM image of the high-nickel polycrystalline precursor prepared in Example 1 of this application; Figure 3 The image shows the XRD pattern of the high-nickel polycrystalline precursor prepared in Example 1 of this application. Figure 4 This is a SEM image of the high-nickel polycrystalline precursor prepared in Comparative Example 1 of this application; Figure 5 This is a SEM image of the high-nickel polycrystalline precursor prepared in Comparative Example 2 of this application; Figure 6 This is a SEM image of the high-nickel polycrystalline precursor prepared in Comparative Example 3 of this application. Detailed Implementation

[0026] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0027] In this embodiment of the application, a high-nickel polycrystalline precursor is provided, the chemical formula of which is: Ni x Co y Mn z M w (OH)2; wherein M includes at least one of Zr, Ti, V, Mo, Zn, W and Al; 0.80≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.04, 0≤w≤0.01; and x+y+z+w=1.

[0028] The chemical formula of the above-mentioned high-nickel polycrystalline precursor is: Ni x Co y Mn z M w (OH)2, in which Ni(x) is the main element, and its mole fraction is between 0.80 and 0.98, for example, it can be 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.94, 0.96, 0.98, etc. It belongs to the high-nickel ternary precursor design, which is conducive to the formation of high-capacity cathode materials in the subsequent lithiation process, and meets the capacity requirements of high-energy-density batteries.

[0029] Co (y) and Mn (z) are used as auxiliary components, controlled within the ranges of 0.02–0.06 (e.g., 0.02, 0.03, 0.04, 0.05, 0.06, etc.) and 0–0.04 (e.g., 0, 0.01, 0.02, 0.03, 0.04, etc.), respectively. Co helps improve the electronic conductivity of the material, while Mn mainly enhances the stability of the crystal structure. The two work synergistically to balance cycle performance and safety performance.

[0030] The M element (w) is a trace dopant element, which can be selected from at least one of Zr, Ti, V, Mo, Zn, W, and Al. For example, it can be Ti+Zn+Al, or Ti or Al, etc. The doping amount is controlled between 0 and 0.01, for example, it can be 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, etc. Doping with multiple different M elements helps to improve the crystallinity of the precursor, the thermal stability during sintering, and the structural integrity of the final cathode material without destroying the main crystal structure.

[0031] Meanwhile, by limiting x+y+z+w=1 in the chemical formula, the total sum of the molar ratios of the metal components is kept constant, thereby improving the accuracy of component control and the consistency of the final product during the co-precipitation process, which is conducive to industrial scale-up and quality stability.

[0032] In summary, this embodiment achieves a balance between capacity enhancement, structural stability, and compositional uniformity by precisely defining the range and proportion of metal components, providing an excellent precursor basis for the preparation of high-performance ternary cathode materials.

[0033] In a further embodiment, in the chemical formula of the high-nickel polycrystalline precursor, 0.9 ≤ x ≤ 0.96; and / or, 0.03 ≤ y ≤ 0.05; and / or, 0.01 ≤ y ≤ 0.03.

[0034] In some embodiments, the high-nickel polycrystalline precursor is a secondary particle assembled from primary particles, and has a composite structure.

[0035] The above further defines the structural characteristics of the high-nickel polycrystalline precursor. This precursor is composed of secondary particles assembled from primary particles and has a composite structure.

[0036] The primary particles serve as the basic building blocks, forming primary particles with regular morphology and controllable particle size through a controlled co-precipitation reaction. These primary particles are further assembled to form larger secondary particles, enabling the material to possess both good microscopic reactivity and macroscopic compaction properties. This structural design helps to improve the material's bulk density and mechanical strength while maintaining a high specific surface area.

[0037] In some embodiments, the high-nickel polycrystalline precursor is a secondary particle, including the following two types: (1) Inner layer and outer layer; (2) Inner layer, transition layer and outer layer; The inner layer is a porous inner layer, and the density of the inner layer is less than that of the outer layer.

[0038] The aforementioned secondary particles can possess a layered composite structure, including at least an inner layer and an outer layer, or further including an intermediate transition layer. The inner layer can be a dense porous structure with high porosity, which is beneficial for the diffusion and reaction of lithium ions during subsequent lithiation. The outer layer is formed by the accumulation of relatively dense primary particles, providing structural support and compaction advantages. By adjusting the particle growth conditions in different regions (such as changes in alkalinity and precipitation time), directional layered growth of the secondary particles can be achieved.

[0039] In addition, the inner layer has a lower density than the outer layer. That is, the relatively loose and porous inner layer (core) is conducive to the capacity performance of the material, while the relatively dense outer layer is conducive to improving the cycle performance of the material. The structure of the loose core and the dense outer layer is conducive to ensuring the capacity performance of the cathode material while also taking into account the cycle performance of the material.

[0040] On the one hand, the relatively low-density, porous core (inner layer) is beneficial for increasing the lithium-ion transport channels in the ternary cathode material, thereby improving its activity and capacity performance. On the other hand, the relatively high-density, dense outer layer is beneficial for improving structural stability and enhancing the high-temperature cycling performance of the cathode material. This helps to achieve a stress regulation mechanism of inner flexibility and outer rigidity in the overall structure, thereby reducing the risk of structural collapse and crack propagation during subsequent sintering or cycling, and improving the cycling stability and mechanical integrity of the final cathode material.

[0041] This structural design, combined with the chemical composition of the precursor, lays the foundation for the formation of high-density, high-stability, and high-performance lithium-ion battery cathode materials.

[0042] In some embodiments, the outer layer of the high-nickel polycrystalline precursor is composed of triangular sheet-like primary particles; the triangular sheets are arranged in a flat manner during sintering and compaction, and the sheet direction is perpendicular to the direction of applied pressure.

[0043] The aforementioned primary particles are stacked flat on the outer layer, with the outer layer of primary particle sheets perpendicular to the pressure direction during compaction. This arrangement significantly enhances the mechanical strength of the precursor secondary particles, resulting in a cathode material with a significantly higher compaction density than common secondary particle products.

[0044] When the outer triangular sheet-like primary particles are arranged in a flat pattern with the sheet direction perpendicular to the applied pressure direction, the contact area between the particles increases and the interaction force between the particles is enhanced during compaction, thereby improving the overall mechanical strength and stability of the material. Simultaneously, this arrangement also facilitates lithium-ion transport within the material, as lithium ions encounter less resistance during transport, thus improving the material's electrochemical performance.

[0045] In addition, the outer primary particles of the precursor particles have a triangular shape, which can ensure a high tap density of the precursor, thus ensuring a high compaction density of the cathode material, while also increasing the energy density of the material and taking into account the cycle performance of the material.

[0046] In some embodiments, the triangular sheet has at least one of the following features: A. The side length of the triangle is 500nm~3000nm; for example, it can be 500nm, 1000nm, 1500nm, 2000nm, 2500nm, 3000nm, etc.

[0047] In the preparation of high-nickel polycrystalline precursors, the morphology and size of primary particles have a significant impact on the properties of the final material. The selection of the side length range of 500 nm to 3000 nm for triangular plate-shaped primary particles is based on a comprehensive consideration of material properties.

[0048] Choosing triangular, plate-shaped primary particles with this range of side lengths ensures sufficient surface area and active sites, facilitating subsequent chemical reactions and lithium-ion transport. Furthermore, it allows the particles to form a more compact structure during stacking and sintering, improving the material's compaction density and energy density. If the side length is too small, insufficient contact area between particles may affect the material's compaction density and mechanical strength; conversely, if the side length is too large, the transport channels between particles may narrow, impacting lithium-ion transport efficiency and consequently affecting the material's electrochemical performance.

[0049] B. The thickness of the triangle is 200nm~500nm; for example, it can be 200nm, 300nm, 400nm, 500nm, etc.

[0050] The thickness of the primary particles also has a significant impact on their performance. A thickness range of 200 nm to 500 nm is chosen to ensure sufficient particle strength while maintaining good electrochemical activity.

[0051] Choosing triangular, sheet-like primary particles within this thickness range ensures sufficient mechanical strength during sintering, preventing breakage or deformation. Simultaneously, an appropriate thickness facilitates lithium-ion transport within the particles, avoiding excessively long transport paths due to excessive particle thickness, thus improving the material's electrochemical performance. If the thickness is too small, the particles may break during sintering, affecting the material's structural integrity; if the thickness is too large, it increases lithium-ion transport resistance, reducing material performance.

[0052] C. The number of triangular lamellar layers in the direction of crystal plane (101) is 120 to 150. For example, it can be 120, 130, 140, 150, etc.

[0053] The number of triangular lamellae along the (101) crystal plane is an important indicator of a material's crystallinity and structural stability. By controlling the number of lamellae, the crystal structure of the material can be optimized, thereby improving its electrochemical performance.

[0054] Choosing a triangular lamellar number of 120-150 layers ensures high crystallinity and structural stability in the material. Highly crystallinity materials have fewer crystal defects (such as dislocations and vacancies), thus improving structural stability and cycling performance. Simultaneously, an appropriate number of lamellar layers also facilitates lithium-ion transport within the material, as lithium ions encounter fewer obstacles during transport.

[0055] If the number of layers is too small, the material may lack sufficient crystallinity, affecting its structural stability and electrochemical performance; if the number of layers is too large, the material may have an overly complex structure, increasing the resistance to lithium-ion transport.

[0056] In some embodiments, the secondary particles have at least one of the following structural features: A. The thickness of the outer layer is greater than the particle size of the inner layer.

[0057] In the structural design of high-nickel polycrystalline precursors, the relationship between the thickness of the outer layer and the grain size of the inner layer has a significant impact on the overall properties of the material. This structure allows the outer layer to provide additional mechanical strength and structural stability on top of the inner layer.

[0058] The outer layer's greater thickness effectively protects the porous structure of the inner layer, preventing its collapse during sintering. Simultaneously, the dense structure of the outer layer contributes to increased compaction density and energy density. If the outer layer's thickness is smaller than the inner layer's particle size, the porous structure of the inner layer may be exposed, making it susceptible to damage during sintering and thus affecting the material's overall performance.

[0059] B. The secondary particles of the high-nickel polycrystalline precursor have a particle size of 10μm to 17μm; for example, they can be 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, etc.

[0060] A particle size range of 10μm to 17μm ensures high compaction density and energy density in the material. Larger particle sizes improve the material's mechanical strength and structural stability, while also contributing to higher compaction density. If the particle size is too small, insufficient compaction density may occur, affecting energy density; if the particle size is too large, insufficient mechanical strength may result in the material being prone to breakage or deformation during sintering.

[0061] C. The particle size of the inner layer is 1μm to 3μm; for example, it can be 1μm, 2μm, 3μm, etc.

[0062] A particle size range of 1μm to 3μm ensures that the inner layer has a sufficiently porous structure, thereby increasing the lithium-ion transport channels and improving the material's capacity performance. If the particle size is too small, the porous structure of the inner layer may become too dense, affecting the lithium-ion transport efficiency; if the particle size is too large, it may cause the inner layer structure to collapse, affecting the overall performance of the material.

[0063] D. The thickness of the transition layer is 2μm to 7μm; for example, it can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, etc.

[0064] A thickness range of 2μm to 7μm ensures that the transition layer effectively connects the inner and outer layers, acting as a buffer and transition layer. The presence of the transition layer allows for a smooth transition between the porous structure of the inner layer and the dense structure of the outer layer, avoiding abrupt structural changes. If the thickness of the transition layer is too small, the connection between the inner and outer layers may be weak, affecting the structural stability of the material; if the thickness of the transition layer is too large, it may increase the internal stress of the material, affecting its performance.

[0065] E. The thickness of the outer layer is 7μm to 11μm. For example, it can be 7μm, 8μm, 9μm, 10μm, 11μm, etc.

[0066] A thickness range of 7μm to 11μm ensures that the outer layer has sufficient mechanical strength to protect the porous structure of the inner layer and prevent its collapse during sintering. Simultaneously, the dense structure of the outer layer helps to improve the material's compaction density and energy density. If the outer layer is too thin, the material may lack sufficient mechanical strength and be prone to breakage or deformation during sintering; if the outer layer is too thick, it may increase the internal stress of the material, affecting its performance.

[0067] In some embodiments, the crystal form of the high-nickel polycrystalline precursor satisfies at least one of the following crystallinity characteristics: A. The full width at half maximum (FWHM) of the (001) crystal plane is not greater than 0.300°.

[0068] The full width at half maximum (FWHM) in X-ray diffraction (XRD) is an important indicator of the crystallinity of a material. The smaller the FWHM, the larger the grain size and the higher the crystallinity.

[0069] When the FWHM of the (001) crystal plane is not greater than 0.300°, it indicates that the grain size in this direction is large, the crystal structure is complete, and there are no obvious defects, indicating that the material has high crystallinity in this direction. Materials with high crystallinity have fewer crystal defects (such as dislocations, vacancies, etc.), thereby improving the structural stability and cycle performance of the material.

[0070] If FWHM is greater than 0.300°, it may result in low crystallinity of the material, with more defects in the crystal structure, which will affect the electrochemical performance of the material.

[0071] B. The full width at half maximum (FWHM) of the (101) crystal plane is not greater than 0.300°.

[0072] When the FWHM of the (101) crystal plane is not greater than 0.300°, it indicates that the grain size in this direction is relatively large, the crystal structure is complete, and there are no obvious defects, indicating that the material has high crystallinity in this direction. Materials with high crystallinity have fewer crystal defects, thereby improving the structural stability and cycle performance of the material. At the same time, the high crystallinity of the (101) crystal plane also helps to improve the mechanical strength and compaction density of the material.

[0073] If FWHM is greater than 0.300°, it may result in low crystallinity of the material, with more defects in the crystal structure, which will affect the electrochemical performance of the material.

[0074] C. The crystal deformation stacking fault rate (FD) is 0% to 2%. For example, it can be 0%, 1%, 2%, etc. Deformation stacking fault rate (FD) is an indicator that measures the number of stacking faults in the crystal structure of a material. The lower the stacking fault rate, the more complete the crystal structure and the fewer defects.

[0075] The crystal deformation layer fault rate is calculated using the following formula: FD=0.1552×FWHM(101)-0.03233×FWHM(102)-0.4399 / D(001).

[0076] Wherein, FWHM(101) represents the half-width at half maximum (WHM) of the (101) diffraction peak; FWHM(102) represents the half-width at half maximum (WHM) of the (102) diffraction peak, in degrees; and D(001) is the grain size corresponding to the (001) crystal plane, in nm.

[0077] When the stacking fault rate (FD) of a crystal is between 0% and 2%, it indicates that the material has a low number of stacking faults, a complete crystal structure, and few defects. Such highly crystallized materials exhibit good structural stability and cycling performance. Materials with low stacking fault rates can better maintain their structural integrity during sintering, thereby improving the material's mechanical strength and electrochemical performance. If the stacking fault rate exceeds 2%, it may lead to more defects in the crystal structure, affecting the material's structural stability and electrochemical performance.

[0078] This application provides a method for preparing a high-nickel polycrystalline precursor as described in any of the foregoing embodiments, comprising: Step S1: Prepare a metal salt solution according to the molar ratio of metal elements in the chemical formula of the high-nickel polycrystalline precursor.

[0079] The chemical formula of the high-nickel polycrystalline precursor is: Ni x Co y Mn z M w (OH)2; Wherein, M includes at least one of Zr, Ti, V, Mo, Zn, W and Al; 0.80≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.04, 0≤w≤0.01; and x+y+z+w=1.

[0080] To ensure that the chemical composition of the precursor meets the design requirements, a metal salt solution needs to be precisely prepared according to these molar ratios. First, the corresponding metal salts (such as nickel sulfate, cobalt sulfate, manganese sulfate, etc.) are calculated and weighed according to the molar ratio of each metal element in the high-nickel polycrystalline precursor. Then, these metal salts are dissolved in water to prepare the metal salt solution.

[0081] In some embodiments, the metal ion concentration of the metal salt solution is approximately 1.5 mol / L to 3.0 mol / L. For example, it can be 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, etc.

[0082] Precise preparation of metal salt solutions is a crucial step in ensuring the accurate chemical composition of the precursor. By controlling the molar ratio of the metal salts, the final precursor can be guaranteed to have the expected chemical composition and properties. Inaccurate metal salt ratios may cause the precursor's chemical composition to deviate from the design values, thereby affecting the material's electrochemical performance.

[0083] In step S2, the metal salt solution, precipitant solution, and complexing agent solution are mixed to carry out a co-precipitation reaction, so that the particles grow to 12μm~14μm. After solid-liquid separation and drying, a high-nickel polycrystalline precursor is obtained.

[0084] Coprecipitation is a core step in the preparation of high-nickel polycrystalline precursors. By controlling the reaction conditions, metal ions can be uniformly precipitated in solution, forming a precursor with specific structure and properties. During the coprecipitation reaction, the growth process of primary particles can be controlled to achieve specific morphologies and structures. Improper control of reaction conditions may result in particle morphology and structure that do not meet design requirements, thus affecting the material's performance.

[0085] It should be noted that the co-precipitation reaction of high-nickel polycrystalline precursors can be carried out under a protective atmosphere. Using a protective gas can effectively prevent the oxidation of metal ions, ensuring the smooth progress of the reaction and the purity of the product. For example, it can include, but is not limited to, nitrogen, argon, carbon dioxide, hydrogen, helium, etc.

[0086] After the coprecipitation reaction is complete, the reaction product needs to be separated from the reaction solution and dried to obtain a dry high-nickel polycrystalline precursor. For example, the reaction precipitate slurry can be aged, washed, and centrifuged to remove impurities and unreacted reagents from the reaction solution. The resulting precipitate is then dried. Specifically, the drying temperature can be controlled between 60℃ and 100℃ (e.g., 60℃, 70℃, 80℃, 90℃, 100℃, etc.), and the drying time can be between 12 hours and 24 hours (e.g., 12 hours, 13 hours, 14 hours, 15 hours, 17 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, etc.).

[0087] In addition, the dried precursor can be sieved and demagnetized to ensure the purity and quality of the product.

[0088] The above solid-liquid separation and drying processes are steps to ensure the quality of the precursor.

[0089] Aging and washing remove impurities from the reaction solution, improving the purity of the precursor. Drying removes moisture from the precursor, giving it good storage and processing properties. Sieving and demagnetization further improve product quality, ensuring its performance in subsequent applications. Inadequate processing steps may result in impurities or moisture in the precursor, affecting material performance and lifespan.

[0090] In some embodiments, the coprecipitation reaction conditions include at least one of the following conditions: A. Reaction temperature: 50℃~70℃; for example, it can be 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, etc.

[0091] Reaction temperature is one of the key parameters in coprecipitation reactions, directly affecting the precipitation rate of metal ions, particle growth, and the final crystal structure.

[0092] Within a temperature range of 50℃ to 70℃, the precipitation rate of metal ions is moderate, which is conducive to the formation of uniform particles. In some embodiments, the reaction temperature can be 60℃ to 65℃.

[0093] Too low a temperature (e.g., reaction temperature < 50℃) will result in a slow precipitation rate, incomplete particle growth, and affect crystallinity and particle uniformity. The morphology, size, and crystallinity of the primary particles will not meet the requirements of this technology. Too high a temperature (e.g., reaction temperature > 70℃) may cause the particles to grow too fast and agglomerate. This will prevent the primary particles in the outer shell layer from being laid out and stacked on the outside of the inner layer, affecting the particle size distribution and structural stability of the final product.

[0094] B. pH value 11~12; for example, it can be 11, 11.1, 11.2, 11.3, 11.5, 11.7, 11.8, 11.9, 12, etc.

[0095] pH is another key parameter controlling the precipitation process of metal ions, directly affecting the morphology and particle structure of the precipitate.

[0096] Under conditions of pH 11-12, metal ions can be uniformly precipitated as hydroxides. In some embodiments, the pH can be 11.30-11.60.

[0097] If the pH value is below 11, precipitation may be incomplete, resulting in irregular particle morphology. If the pH value is above 12, precipitation may be too rapid, leading to agglomeration and affecting particle uniformity and crystallinity.

[0098] C. Alkalinity: 15g / L~35g / L; for example, it can be 15g / L, 16g / L, 17g / L, 18g / L, 19g / L, 20g / L, 25g / L, 30g / L, 35g / L, etc.

[0099] Alkalinity (which can refer to the concentration of ammonia in the solution) plays an important role in coprecipitation reactions, especially in controlling the growth direction and morphology of particles.

[0100] Under alkalinity conditions of 15 g / L to 35 g / L, the presence of ammonia can adjust the pH of the solution and also buffer the precipitation of metal ions.

[0101] In some implementations, the alkalinity can be 25 g / L to 30 g / L.

[0102] Proper alkalinity helps form uniform particles, preventing them from being too dense or too loose. If the alkalinity is too low, it may lead to uneven particle growth; if the alkalinity is too high, it may cause the particles to grow too quickly and agglomerate.

[0103] D. Rotation speed 300r / min~400r / min; for example, it can be 300r / min, 310r / min, 320r / min, 330r / min, 340r / min, 350r / min, 360r / min, 370r / min, 380r / min, 390r / min, 400r / min, etc.

[0104] Stirring speed plays an important role in coprecipitation reactions, as it affects the uniformity of solution mixing and the growth environment of particles.

[0105] Within a rotation speed range of 300 rpm to 400 rpm, the solution can be thoroughly mixed, ensuring a uniform distribution of metal ions. An appropriate rotation speed can prevent particle sedimentation and avoid excessive local supersaturation. If the rotation speed is below 300 rpm, the solution may not mix uniformly, leading to particle sedimentation; if the rotation speed is above 400 rpm, it may cause particle breakage, affecting the particle morphology and structure.

[0106] E. The reaction time is 100 to 200 hours; for example, it can be 100 hours, 110 hours, 120 hours, 130 hours, 140 hours, 150 hours, 160 hours, 170 hours, 180 hours, 190 hours, 200 hours, etc.

[0107] Reaction time is an important parameter in coprecipitation reactions, as it directly affects particle growth and the final particle size distribution.

[0108] Within a reaction time of 100 to 200 hours, the particles have sufficient time to grow uniformly and form precursors with specific structures. If the reaction time is less than 100 hours, the particles may not grow completely, affecting the performance of the final product; if the reaction time exceeds 200 hours, it may lead to overgrowth of the particles and agglomeration.

[0109] F. The precipitant solution includes NaOH solution.

[0110] The choice of precipitant has a significant impact on the outcome of the coprecipitation reaction. NaOH, as a precipitant, can effectively promote the precipitation of metal ions.

[0111] NaOH solution, as a precipitating agent, can provide sufficient OH-. - Ions promote the precipitation of metal ions to form hydroxides. The concentration and method of addition of NaOH directly affect the precipitation rate and particle morphology. If the NaOH concentration is too low, precipitation may be incomplete; if the concentration is too high, precipitation may be too rapid, leading to agglomeration.

[0112] In addition, the precipitant can also be potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium hydroxide, etc. In this embodiment, the precipitant can be any one or a combination of the above-mentioned precipitant substances, provided that the final product performance of the high-nickel polycrystalline precursor is acceptable. For example, a mixed precipitant composed of potassium hydroxide and calcium hydroxide.

[0113] G. The complexing agent solution includes ammonia.

[0114] Complexing agents play an important role in coprecipitation reactions, especially in controlling the precipitation rate of metal ions and the morphology of particles.

[0115] Ammonia, acting as a complexing agent, can form complexes with metal ions, thus regulating the precipitation rate of metal ions. An appropriate ammonia concentration can prevent metal ions from precipitating too quickly and avoid particle agglomeration. If the ammonia concentration is too low, metal ions may precipitate too quickly, affecting particle uniformity; if the concentration is too high, the complex may become too stable, hindering precipitate formation.

[0116] In addition, the complexing agent can also be ammonium bicarbonate, ammonium carbonate, EDTA, urea, etc. In this embodiment, the complexing agent can be any one or a combination of the above substances, provided that the final product performance of the high-nickel polycrystalline precursor is acceptable.

[0117] In some embodiments, the coprecipitation reaction includes the following three stages: First stage reaction: Step S21, the first stage reaction is carried out under the condition of alkalinity below 5 g / L to obtain the first reaction precipitate slurry, and the nucleation of primary particles in the first reaction precipitate slurry is controlled to form a porous inner layer.

[0118] In the initial stage of the coprecipitation reaction, it is necessary to control the nucleation process of metal ions to form an inner layer with a specific structure.

[0119] In some implementations, the alkalinity of the first-stage reaction can be further increased to 3 g / L to 5 g / L.

[0120] At lower alkalinity, metal ions precipitate more slowly, which is conducive to the formation of uniform nucleation sites. Lower alkalinity prevents metal ions from precipitating too quickly, thus forming a loose and porous inner structure. If the alkalinity is too high, metal ions may precipitate too quickly, forming a dense structure, which is detrimental to lithium ion transport and the material's capacity performance.

[0121] Second stage reaction: Step S22, the second stage reaction is carried out under the condition of alkalinity of 5g / L to 15g / L (for example, it can be 5g / L, 6g / L, 7g / L, 8g / L, 9g / L, 10g / L, 11g / L, 12g / L, 13g / L, 14g / L, 15g / L, etc.) to obtain the second reaction precipitate slurry, so that the primary particles in the second reaction precipitate slurry are transformed from radial to flat stacking, forming a transition layer outside the inner layer.

[0122] After the first-stage reaction forms the inner layer, it is necessary to further control the growth direction of the primary particles, transforming them from a radial pattern to a planar stacking pattern, thus forming a transition layer. The formation of the transition layer helps to create a smooth transition from the inner to the outer layer, improving the structural stability of the material.

[0123] Under moderate alkalinity, the precipitation rate of metal ions is moderate, which is conducive to the transformation of the primary particle growth direction from radial to planar stacking. Appropriate alkalinity can regulate the precipitation rate of metal ions, preventing excessively rapid particle growth and agglomeration. If the alkalinity is too low, the change in growth direction may not be achieved; if the alkalinity is too high, it may cause excessively rapid particle growth, affecting the uniformity of the transition layer.

[0124] The third stage reaction: Step S23, the third stage reaction is carried out under the condition of alkalinity of 15g / L to 35g / L (for example, it can be 15g / L, 16g / L, 17g / L, 18g / L, 19g / L, 20g / L, 21g / L, 22g / L, 23g / L, 24g / L, 25g / L, 26g / L, 27g / L, 28g / L, 29g / L, 30g / L, 31g / L, 32g / L, 33g / L, 34g / L, 35g / L, etc.) to obtain the third reaction precipitate slurry. The primary particles in the third reaction precipitate slurry are induced to form triangular plate-like morphology and be arranged in a flat stack to construct the outer layer outside the transition layer.

[0125] In some embodiments, the alkalinity of the second-stage reaction can be further set at 24 g / L to 30 g / L.

[0126] After the inner and transition layers are formed in the first two stages, the growth of the primary particles needs to be further controlled to form a triangular morphology and be arranged in a flat, stacked pattern to construct the outer layer. The triangular morphology of the outer layer helps to improve the mechanical strength and compaction density of the material.

[0127] Under higher alkalinity conditions, the precipitation rate of metal ions is faster, which is conducive to the formation of triangular plate-like morphologies and their flat, stacked arrangement of primary particles. Higher alkalinity provides sufficient ammonium ions to regulate the precipitation rate of metal ions and promote the flat growth of primary particles. If the alkalinity is too low, triangular plate-like morphologies may not form; if the alkalinity is too high, it may cause particles to grow too quickly, affecting the structural stability of the outer layer.

[0128] Treatment schemes for different stages of the coprecipitation reaction can specifically include: (1) First stage reaction: Using the precipitant solution, the complexing agent solution and water as the reaction base liquid, a first mixing treatment is performed with the metal salt solution to obtain a mixed reaction solution. During the first mixing treatment, the pH of the mixed reaction solution is adjusted to 11~12 and the alkalinity is adjusted to 3g / L~5g / L by the precipitant solution and the complexing agent solution. The particle size D in the slurry is... 50 The reaction is stopped when the particle size of the inner layer reaches 1μm~3μm, and the first reaction precipitate slurry is obtained.

[0129] In the above steps, in the initial stage of the coprecipitation reaction, it is necessary to control the nucleation process of metal ions to form an inner layer with a specific structure.

[0130] At lower alkalinity, metal ions precipitate more slowly, which is conducive to the formation of uniform nucleation sites. Lower alkalinity prevents metal ions from precipitating too quickly, thus forming a loose and porous inner structure. If the alkalinity is too high, metal ions may precipitate too quickly, forming a dense structure, which is detrimental to lithium ion transport and the material's capacity performance.

[0131] (2) Second stage reaction: During the second mixing process, the pH of the second reaction precipitate slurry is adjusted to 11~12 and the alkalinity is 5g / L~15g / L by the precipitant solution and the complexing agent solution, and the particle size D in the slurry is adjusted. 50 The reaction is stopped when the thickness of the transition layer reaches 2μm~7μm, and the second reaction precipitate slurry is obtained.

[0132] After the first-stage reaction forms the inner layer, it is necessary to further control the growth direction of the primary particles, transforming them from a radial pattern to a planar stacking pattern, thus forming a transition layer. The formation of the transition layer helps to create a smooth transition from the inner to the outer layer, improving the structural stability of the material.

[0133] Under moderate alkalinity, the precipitation rate of metal ions is moderate, which is conducive to the transformation of the primary particle growth direction from radial to planar stacking. Appropriate alkalinity can regulate the precipitation rate of metal ions, preventing excessively rapid particle growth and agglomeration. If the alkalinity is too low, the change in growth direction may not be achieved; if the alkalinity is too high, it may cause excessively rapid particle growth, affecting the uniformity of the transition layer.

[0134] (3) Third stage reaction: During the third mixing process, the pH of the third reaction precipitate slurry is adjusted to 11~12 and the alkalinity is adjusted to 15g / L~35g / L by the precipitant solution and the complexing agent solution, and the particle size D in the slurry is adjusted. 50 The reaction is stopped when the thickness of the outer layer reaches 7μm~11μm, and the third reaction precipitate slurry is obtained.

[0135] After the inner and transition layers are formed in the first two stages, the growth of the primary particles needs to be further controlled to form a triangular morphology and be arranged in a flat, stacked pattern to construct the outer layer. The triangular morphology of the outer layer helps to improve the mechanical strength and compaction density of the material.

[0136] Under higher alkalinity conditions, the precipitation rate of metal ions is faster, which is conducive to the formation of triangular plate-like morphologies and their flat, stacked arrangement of primary particles. Higher alkalinity provides sufficient ammonium ions to regulate the precipitation rate of metal ions and promote the flat growth of primary particles. If the alkalinity is too low, triangular plate-like morphologies may not form; if the alkalinity is too high, it may cause particles to grow too quickly, affecting the structural stability of the outer layer.

[0137] In some embodiments, the reaction conditions for the first stage reaction include: a reaction temperature of 60°C to 65°C; and / or, the first mixing treatment is stirring mixing at a speed of 50 r / min to 400 r / min. For example, the speed can be 50 r / min, 60 r / min, 80 r / min, 100 r / min, 200 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, etc.

[0138] In some embodiments, the rotational speed can preferably be 300 r / min to 400 r / min; In some embodiments, the reaction conditions for the second stage reaction include: a reaction temperature of 60°C to 65°C; and / or, the second mixing treatment is stirring mixing at a speed of 50 r / min to 400 r / min; and / or, for example, the speed can be 50 r / min, 60 r / min, 80 r / min, 100 r / min, 200 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, etc.

[0139] In some embodiments, the reaction conditions for the third stage reaction include: a reaction temperature of 60°C to 65°C; and / or, the second mixing treatment is stirring mixing at a speed of 50 r / min to 400 r / min. For example, the speed can be 50 r / min, 60 r / min, 80 r / min, 100 r / min, 200 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, etc.

[0140] In some embodiments, the rotational speed can preferably be 100 r / min to 300 r / min; This application provides a cathode material, which is prepared from the high-nickel polycrystalline precursor as described in the foregoing embodiments, or from the high-nickel polycrystalline precursor obtained by the preparation method of the high-nickel polycrystalline precursor as described in the foregoing embodiments.

[0141] The aforementioned cathode material is prepared from a high-nickel polycrystalline precursor with specific chemical composition, structural characteristics, and crystallinity. This cathode material can be a high-nickel polycrystalline precursor, or it can be a material obtained by doping, synthesizing, structurally modifying, physically encapsulating, or coating the high-nickel polycrystalline precursor.

[0142] This application provides an electrode comprising the positive electrode material described in the foregoing embodiments. In addition to the aforementioned positive electrode material, it may also include, but is not limited to, current collectors (such as aluminum foil), conductive agents (such as carbon black, graphene), binders (such as PVDF, CMC), additives (such as ceramic particles, electrolyte additives), solvents (such as water, NMP), separators (such as polyolefins), and electrolytes (such as LiPF6, carbonates). These components together constitute a complete electrode system. By rationally selecting and optimizing the proportions and properties of each component, the performance of the electrode can be further improved to meet the needs of different application scenarios.

[0143] This application provides a battery comprising the electrode sheet described in the foregoing embodiments. In addition to the positive electrode sheet, the battery may also include key components such as a negative electrode material (e.g., graphite, silicon-carbon composite material, lithium metal, etc.), a separator (e.g., polyolefin), an electrolyte (e.g., an organic solvent containing lithium salt), a casing (e.g., steel casing, aluminum casing, soft pack, etc.), and a negative electrode current collector (e.g., copper foil). These components together constitute a complete battery system. By rationally designing and optimizing the performance of each part, the battery's energy density, cycle stability, safety, and lifespan can be further improved to meet the needs of different application scenarios.

[0144] This application provides an electrical device, including a battery as described in the foregoing embodiments.

[0145] The aforementioned electrical equipment can cover multiple application categories, including but not limited to electric vehicles, portable electronic devices, energy storage systems, power tools, medical devices, and smart wearable devices. By employing high-performance batteries, these devices can significantly improve their operating efficiency, battery life, and lifespan, meeting diverse needs in different application scenarios.

[0146] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0147] Table 1. Comparison of key parameters in different embodiments

[0148] Table 2. Comparison of key parameters in different comparative examples

[0149] In the left columns of Tables 1 and 2 above, "Stage 1," "Stage 2," and "Stage 3" represent the first-stage reaction, the second-stage reaction, and the third-stage reaction, respectively. Temperature refers to the reaction temperature, in °C. "Example" indicates an example, such as "Example 1" representing Example 1.

[0150] Example 1 In this embodiment, a high-nickel polycrystalline precursor was prepared.

[0151] Experimental methods: Specific process parameters can be found in Table 1.

[0152] 1. Raw material preparation: Weigh nickel sulfate, cobalt sulfate crystals, and manganese sulfate crystals according to the molar ratio of nickel, cobalt, and manganese, and prepare a 2 mol / L homogeneous ternary metal salt solution.

[0153] A certain amount of pure water, NaOH solution (concentration 32wt%), and ammonia water (concentration 21wt%) were added to the reaction vessel and stirred evenly at a constant temperature of 60℃ to obtain the target base solution with a pH of 11.00-12.00. 2. Coprecipitation reaction: (1) First stage reaction: Under nitrogen protection, a metal salt solution (flow rate: 250 L / h), NaOH (flow rate: 100 L / h), and ammonia (flow rate: 15 L / h) are introduced into the reactor containing the bottom liquid to carry out a co-precipitation reaction. The reaction temperature, pH, alkalinity, and rotation speed are controlled; the slurry particle size D 50 When the average thickness requirement of the loose and porous inner layer is met, the first reaction precipitate slurry is obtained; (2) Second stage reaction: Adjust the reaction temperature, pH, alkalinity and rotation speed of the first reaction sedimentation slurry, and equalize the slurry particle size D. 50 When the average thickness requirement of the transition layer is met, the second reaction precipitate slurry is obtained; (3) Third stage reaction: Adjust the reaction temperature, pH, alkalinity and rotation speed of the second reaction precipitate slurry. During the reaction, the mother liquor is discharged through the thickening equipment. The discharge rate is consistent with the total feed rate. The slurry particle size D is equal to that of the mother liquor. 50 When the average thickness requirement of the outer layer is met, a metal hydroxide reaction precipitate slurry with an average diameter of 13.5 μm is obtained.

[0154] 3. Post-reaction treatment: After aging, washing, centrifuging, drying, sieving, and demagnetizing the reaction precipitate slurry, highly crystalline Ni was obtained. 0.92 Co 0.05 Mn 0.03 (OH)2 material.

[0155] Examples 2 to 9 In each embodiment, high-nickel polycrystalline precursors were prepared. The experimental methods were basically the same as in Example 1, except that the parameters can be found in Table 1.

[0156] Comparative Examples 1 to 3 In each embodiment, high-nickel polycrystalline precursors were prepared. The experimental methods were basically the same as in Example 1, except that the parameters can be found in Table 2.

[0157] Test experiment: Experimental methods: (1) Particle size distribution test: Malvern laser particle size analyzer MS3000; test conditions: add a certain amount of sample (about 0.07g) into pure water (800-850mL), do not sonicate, pump speed 2500 rpm, light shading degree reaches 10-13%, test results.

[0158] (2) TD test: Refer to GB / T5162-2006, Determination of tap density of metal powder.

[0159] Experimental results: Table 3. Test results of the examples and comparative examples (1)

[0160] Table 4. Test results of the examples and comparative examples (2)

[0161] Analysis: The performance parameters of the precursors in Examples 1 to 9, and Comparative Examples 1 to 3, are shown in Table 3-4. According to Table 3-4, the precursor in Comparative Example 1, due to the excessively high pH during preparation, resulted in a mixed morphology of triangular flakes and dots, and the outer primary particles did not fully develop into a planar stacked structure. The precursor in Comparative Example 2, due to the excessively high synthesis temperature and excessively low alkalinity during preparation, was difficult to obtain a planar stacked structure. The precursor in Comparative Example 3, due to the excessively low synthesis temperature and low alkalinity during preparation, did not obtain a planar stacked structure.

[0162] As can be seen from the comparison in Table 3-4, when the element ratio is the same, the overall battery performance of Example 1 of the present invention is the best. This is due to its loose porous inner layer structure and the outer triangular sheet stacked composite structure. The reasonable average thickness ratio of the inner and outer layers and the high crystallinity give it the highest compaction density, high capacity and excellent cycle performance.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high nickel polycrystalline precursor, characterized in that, The high-nickel polycrystal precursor has a chemical formula of: Ni x Co y Mn z M w (OH)2; M includes at least one of Zr, Ti, V, Mo, Zn, W and Al; 0.80≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.04, 0≤w≤0.01; and x+y+z+w=1.

2. The high nickel polycrystalline precursor of claim 1, wherein, The high-nickel polycrystal precursor is a secondary particle assembled by primary particles, and has a composite structure; and / or, The high-nickel polycrystal precursor is a secondary particle, which includes: an inner layer and an outer layer; or, an inner layer, a transition layer and an outer layer; The inner layer is a porous inner layer, and the density of the inner layer is less than that of the outer layer.

3. The high nickel polycrystalline precursor of claim 2, wherein, The outer layer of the high-nickel polycrystal precursor is composed of triangular flaky primary particles; The triangular flake is arranged in a flat manner during sintering and compaction, and the flake layer direction is perpendicular to the pressure application direction.

4. The high nickel polycrystalline precursor of claim 3, wherein, The triangular flake layer has at least one of the following characteristics: A. The side length of the triangle is 500nm-3000nm; B. The thickness of the triangle is 200nm-500nm; C. The number of the triangular flake layers in the (101) crystal plane direction is 120-150.

5. The high nickel polycrystalline precursor of claim 4, wherein, The secondary particle has at least one of the following structural characteristics: A. The thickness of the outer layer is greater than the particle size of the inner layer; B. The particle size of the secondary particle of the high-nickel polycrystal precursor is 10μm-17μm; C. The particle size of the inner layer is 1μm-3μm; D. The thickness of the transition layer is 2μm-7μm; E. The thickness of the outer layer is 7μm-11μm.

6. The high nickel polycrystalline precursor of claim 1, wherein, The crystal form of the high-nickel polycrystal precursor satisfies at least one of the following crystallinity characteristics: A. The half-peak width FWHM of the (001) crystal plane is not greater than 0.300°; B. The half-peak width FWHM of the (101) crystal plane is not greater than 0.300°; C. The crystal deformation layer dislocation rate FD is 0%-2%.

7. A method of producing a high nickel polycrystalline precursor according to any one of claims 1 to 6, characterized by, The method comprises: According to the molar ratio of metal elements in the chemical formula of the high-nickel polycrystal precursor, a metal salt solution is prepared; The metal salt solution, a precipitant solution and a complexing agent solution are mixed to perform a co-precipitation reaction, and after solid-liquid separation and drying, a high-nickel polycrystal precursor is obtained.

8. The method of claim 7, wherein the high nickel polycrystalline precursor is prepared by the steps of: mixing a nickel powder and a binder to form a mixture; and compressing the mixture to form the high nickel polycrystalline precursor. The co-precipitation reaction conditions include at least one of the following conditions: A. The reaction temperature is 50℃-70℃; B. The pH value is 11-12; C. The alkalinity is 15g / L-35g / L; D. The rotation speed is 300r / min-400r / min; E. The reaction time is 100 hours-200 hours; F. The precipitant solution includes a NaOH solution; G. The complexing agent solution includes ammonia water.

9. The method for preparing the high-nickel polycrystalline precursor as described in claim 7, characterized in that, The co-precipitation reaction comprises: A first-stage reaction is performed under the condition that the alkalinity is 5g / L or less to obtain a first reaction precipitate slurry, and the nucleation of primary particles in the first reaction precipitate slurry is controlled to form a porous inner layer; A second-stage reaction is performed under the condition that the alkalinity is 5g / L-15g / L to obtain a second reaction precipitate slurry, and the primary particles in the second reaction precipitate slurry are converted from a radial to a flat stacking, thereby forming a transition layer outside the inner layer; The third stage reaction is carried out under the condition that the alkalinity is 15 g / L-35 g / L to obtain a third reaction precipitate slurry, the primary particles in the third reaction precipitate slurry are induced to form a triangular flake shape and are arranged in a flat stack, and an outer layer outside the transition layer is constructed. 10.The preparation method of the high-nickel polycrystal precursor according to claim 9, characterized in that, The first stage reaction comprises: taking the precipitant solution, the complexing agent solution and water as a reaction bottom solution, carrying out a first mixing treatment with the metal salt solution to obtain a mixed reaction liquid, and in the first mixing treatment, the pH of the mixed reaction liquid is adjusted to 11-12 and the alkalinity is adjusted to 3 g / L-5 g / L by the precipitant solution and the complexing agent solution, the particle size D 50 The reaction is stopped when the particle size of the inner layer reaches 1 μm-3 μm, and the first reaction precipitate slurry is obtained; and / or, The second stage reaction comprises: in the process of the second mixing treatment, adjusting the pH of the second reaction precipitation slurry to 11-12 and the alkalinity to 5 g / L-15 g / L by the precipitant solution and the complexing agent solution, adjusting the particle size D 50 satisfying the condition that the thickness of the transition layer reaches 2 μm-7 μm to stop the reaction, and obtaining the second reaction precipitation slurry; and / or, The third stage reaction comprises: in the third mixing process, adjusting the pH of the third reaction precipitation slurry to 11-12 and the alkalinity to 15 g / L-35 g / L by the precipitant solution and the complexing agent solution, and adjusting the particle size D 50 The third reaction precipitation slurry is obtained by stopping the reaction when the thickness of the outer layer reaches 7 μm-11 μm.

11. The method of claim 10, wherein the high nickel polycrystalline precursor is prepared by the steps of: the reaction condition of the first stage reaction comprises: a reaction temperature of 60 ℃-65 ℃; and / or, the first mixing treatment is stirring mixing, and the rotating speed is 50 r / min-400 r / min; and / or, ​ the reaction condition of the second stage reaction comprises: a reaction temperature of 60 ℃-65 ℃; and / or, the second mixing treatment is stirring mixing, and the rotating speed is 50 r / min-400 r / min; and / or, the reaction condition of the third stage reaction comprises: a reaction temperature of 60 ℃-65 ℃; and / or, the second mixing treatment is stirring mixing, and the rotating speed is 50 r / min-400 r / min.

12. A positive electrode material, characterized in that, The positive electrode material is prepared from the high-nickel polycrystal precursor according to any one of claims 1-6, or the high-nickel polycrystal precursor obtained by the preparation method of the high-nickel polycrystal precursor according to claims 7-11.

13. A pole piece characterized by, The positive electrode material according to claim 12 is included.

14. A battery, characterized by The electrode piece according to claim 13 is included.

15. An electrical device, comprising: The battery according to claim 14 is included.

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