Positive electrode material precursor with complex morphological structure, preparation method thereof, lithium ion battery, positive electrode material and electrical equipment

Abstract

The application provides a positive electrode material precursor with a complex morphological structure, a preparation method of the positive electrode material precursor, a lithium ion battery, a positive electrode material and an electrical device, and relates to the field of lithium ion batteries. The precursor comprises a core layer, an intermediate layer and a shell layer; wherein the shell layer comprises relatively wide primary particle clusters A and relatively narrow primary particle clusters B; the primary particle clusters A are in a strip shape; a plurality of primary particle clusters A are arranged in a radiating manner; and the primary particle clusters B are located in the gaps between the plurality of strip-shaped primary particle clusters A. The primary particle clusters A of the secondary particle shell layer of the precursor are in a radiating manner; the positive electrode material prepared by inheriting the structure is more conducive to the entry of lithium salt into the interior of the secondary particle, and the capacity performance is improved; the relatively wide primary particle clusters A act as a framework, and the relatively narrow primary particle clusters B are filled in the gaps between the primary particle clusters A, so that the structural stability of the material can be improved, and the cycle performance can be considered under high battery capacity.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and more particularly to a cathode material precursor with a composite morphological structure and its preparation method, lithium-ion batteries, cathode materials, and electrical equipment. Background Technology

[0002] In recent years, new energy vehicles have experienced rapid development. With the increasing prevalence of new energy vehicles, people are paying more attention to the range of their batteries. As the market develops, end-users are constantly raising new demands for batteries with longer range and higher energy density. Therefore, high-capacity, high-nickel materials have become a breakthrough point for the industry.

[0003] Developing a new cathode material precursor is fundamental to obtaining batteries with higher capacity. Therefore, improving the performance of cathode material precursors has become one of the key research focuses. Summary of the Invention

[0004] The purpose of this invention is to provide a cathode material precursor with a composite morphological structure and its preparation method, a lithium-ion battery, a cathode material, and electrical equipment, so as to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A cathode material precursor with a composite morphological structure, wherein the secondary particles of the precursor include: a core layer, an intermediate layer, and a shell layer;

[0007] The shell layer includes a wider primary particle cluster A and a narrower primary particle cluster B. The primary particle cluster A is strip-shaped, and multiple primary particle clusters A are arranged radially. The primary particle cluster B is located in the gap between multiple primary particle clusters A. The average width b1 of the primary particle cluster A is greater than the average width b2 of the primary particle cluster B.

[0008] Furthermore, cathode material precursors with composite morphological structures:

[0009] The intermediate layer includes a wider primary particle cluster C and a narrower primary particle cluster D. The primary particle cluster C is strip-shaped, and multiple primary particle clusters C are arranged in a radial pattern. The primary particle cluster D is located in the gap between multiple primary particle clusters C. The average width b3 of the primary particle cluster C is greater than the average width b4 of the primary particle cluster D.

[0010] Optionally, the precursor satisfies one or more of the following conditions:

[0011] A. The primary particle cluster B is strip-shaped, and / or the primary particle cluster D is strip-shaped;

[0012] B. The primary particle cluster B is arranged in a non-radiative pattern, and / or the primary particle cluster D is arranged in a non-radiative pattern;

[0013] C. The primary particle cluster B is strip-shaped, and the primary particle cluster A and the primary particle cluster B of the shell form a tree structure. The tree structure includes a trunk substructure composed of multiple primary particle clusters A and a branch structure composed of multiple primary particle clusters B.

[0014] D. The average length a1 of the primary particle cluster A is greater than the average length a2 of the primary particle cluster B;

[0015] E. The average length a1 of the primary particle cluster A is greater than the average length a3 of the primary particle cluster C;

[0016] F. The ratio of the average length a1 of the primary particle cluster A to the average length a3 of the primary particle cluster C is a1:a3 = (1~5):1, optionally, a1:a3 = (2~4):1;

[0017] G. The ratio of the average width b1 of the primary particle cluster A to the average width b3 of the primary particle cluster C is b1:b3 = (0.2~2.5):1;

[0018] H. The ratio of the shell thickness to the radius of the precursor secondary particles is 1:(1.2~2.5);

[0019] I. The ratio of the thickness of the intermediate layer to the radius of the secondary particles of the precursor is 1:(2.3~7.5);

[0020] J. The ratio of the core layer diameter to the secondary particle diameter of the precursor is 1:(3.5~9.7);

[0021] K. The shell is composed of a wider primary particle cluster A and a narrower primary particle cluster B;

[0022] L. The intermediate layer consists of wider primary particle clusters C and narrower primary particle clusters D.

[0023] Furthermore, the cathode material precursor with a composite morphological structure satisfies one or more of the following conditions:

[0024] (1) The average length a1 of the primary particle cluster A is 2000-5000 nm; preferably, a1 is 2800-3700 nm;

[0025] (2) The average width b1 of the primary particle cluster A is 50-500 nm;

[0026] (3) The average length a2 of the primary particle cluster B is 100-600 nm; preferably, a2 is 150-550 nm;

[0027] (4) The average width b2 of the primary particle cluster B is 8-60 nm;

[0028] (5) The average length a3 of the primary particle cluster C is 500-2300 nm; preferably, a3 is 1000-1300 nm;

[0029] (6) The average width b3 of the primary particle cluster C is 50-500 nm;

[0030] (7) The average length a4 of the primary particle cluster D is 100-500 nm; preferably, a4 is 140-500 nm.

[0031] (8) The average width b4 of the primary particle cluster D is 5-55 nm;

[0032] (9) The diameter of the core layer is 0.5-3.6 μm;

[0033] (10) The thickness of the intermediate layer is 0.5-2.7 μm;

[0034] (11) The thickness of the shell is 2.0-4.5 μm;

[0035] (12) The porosity of the core layer is 15-35%;

[0036] (13) The porosity of the intermediate layer is 2-10%;

[0037] (14) The porosity of the shell is 11-20%;

[0038] (15) The secondary particle porosity of the precursor is 8-25%.

[0039] Furthermore, the cathode material precursor with a composite morphological structure satisfies one or more of the following conditions:

[0040] (1) The secondary particle surface of the precursor includes two types of primary particles, namely primary particles ① and primary particles ②, wherein the primary particles ① are located in the gap between multiple primary particles ②;

[0041] (2) The width of the primary particle ① is greater than the width of the primary particle ②;

[0042] (3) There is an acute angle between the two intersecting primary particles ①, and the average angle of the acute angle is >30°;

[0043] (4) The core layer is arranged in a mesh pattern;

[0044] (5) The intermediate layer covers the core layer and is arranged in a radial pattern;

[0045] (6) The shell layer covers the intermediate layer and is arranged in a radial pattern;

[0046] (7) The cathode material precursor with a composite morphological structure contains at least one metallic element selected from nickel, cobalt, and manganese; optionally, the chemical formula of the cathode material precursor with a composite morphological structure is Ni. x Co y Mn 1-x-y M a (OH)₂, wherein 0.3 < x < 0.9, 0 ≤ y ≤ 0.4, 0 ≤ a ≤ 0.1; M is one or more of Co, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb, or Sr; optionally, the chemical formula of the cathode material precursor with the composite morphology is Ni x Mn 1-x (OH)2, where 0.40 < x < 0.85.

[0047] Furthermore, the cathode material precursor with a composite morphological structure satisfies one or more of the following conditions:

[0048] (1) The average particle size D50 of the cathode material precursor with the composite morphology structure is 5.5-18.0 μm; optionally, D50 is 8.0-15.0 μm;

[0049] (2) The BET of the cathode material precursor with the composite morphology is 11-20m. 2 / g;

[0050] (3) The TD of the cathode material precursor with the composite morphology is 1.7-2.2 g / cm³. 3 ;

[0051] (4) The cathode material precursor with the composite morphology has a compaction density of 2.65-2.90 g / cm³ at 147.7 MPa. 3 .

[0052] The present invention also provides a method for preparing the cathode material precursor with the composite morphological structure described above, comprising:

[0053] Raw materials, including a metal salt solution, a precipitant, and a complexing agent, are added to a first base solution to carry out a first reaction until seed crystals are obtained. During the first reaction, the flow rates of the metal salt solution, the precipitant, and the complexing agent are controlled so that the pH value of the system continuously decreases and is then maintained within a first pH range.

[0054] Materials including the metal salt solution, the precipitant, and the complexing agent are added to a second base liquid to carry out a second reaction until the cathode material precursor with the composite morphology is obtained; during the second reaction, the flow rate of the precipitant is controlled so that the pH value of the system continuously decreases and is then maintained within a second pH value range.

[0055] The first base liquid comprises water, the precipitant, and the complexing agent, and the second base liquid comprises water, the precipitant, the complexing agent, and the seed crystals.

[0056] Both the first reaction and the second reaction are carried out under isothermal conditions, with the temperature of the first reaction being 45-65℃ and the temperature of the second reaction being 40-70℃.

[0057] The mother liquor was continuously discharged during both the first and second reactions.

[0058] Furthermore, the preparation method of the cathode material precursor with a composite morphological structure satisfies one or more of the following conditions:

[0059] a. The molar concentration of the metal in the metal salt solution is 1.5-3.5 mol / L;

[0060] b. The pH value of the first base solution is 10-12, and the ammonia concentration of the first base solution is 2-5 g / L;

[0061] c. The pH value of the second substrate is 9-11, and the ammonia concentration of the second substrate is 1.0-5.0 g / L;

[0062] d. The first pH range and the second pH range are each independently 9-11;

[0063] e. The average grain size D50 of the seed crystals is 1-5 μm;

[0064] f. In the first reaction, the flow rate of the metal salt solution is 1-6% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-2.22% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-0.50% / h of the reaction vessel volume.

[0065] g. In the second reaction, the flow rate of the metal salt solution is 1.0-10.0% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-3.70% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-1.00% / h of the reaction vessel volume;

[0066] h. Both the first and second reactions are carried out under stirring conditions, and the stirring speeds for the first and second reactions are independently 100-400 r / min.

[0067] The present invention also provides a lithium-ion battery cathode material, wherein the raw materials of the lithium-ion battery cathode material include the cathode material precursor with the composite morphological structure.

[0068] The present invention also provides a lithium-ion battery, including the aforementioned lithium-ion battery positive electrode material.

[0069] The present invention also provides an electrical device, including the aforementioned lithium-ion battery.

[0070] Compared with the prior art, the beneficial effects of the present invention include:

[0071] The present invention provides a cathode material precursor with a composite morphological structure, comprising a core layer, an intermediate layer, and a shell layer. The shell layer includes wider primary particle clusters A and narrower primary particle clusters B. Multiple primary particle clusters A are arranged radially, and primary particle clusters B are located within the gaps between the multiple strip-shaped primary particle clusters A. The radial arrangement of the primary particle clusters A in the shell layer of this precursor allows lithium salts to penetrate the secondary particles through the pores of the shell layer, improving capacity performance. Simultaneously, the three-layer structure of the secondary particles makes it difficult for shell cracks to extend into the secondary particles, inhibiting crack growth and improving cycle performance. Multiple wider primary particle clusters A serve as a framework, while narrower primary particle clusters B fill the gaps between them, enhancing the material's structural stability, compressive strength, and compaction density. Cathode materials with this structure, when fabricated into batteries, can maintain high battery capacity while ensuring good cycle performance.

[0072] The present invention provides a method for preparing a cathode material precursor with a composite morphology, which obtains the above-mentioned cathode material precursor with a composite morphology through an intermittent solution co-precipitation method.

[0073] The lithium-ion battery cathode material, lithium-ion battery, and electrical equipment provided by this invention have excellent cycle performance and electrochemical performance under large capacity conditions. Attached Figure Description

[0074] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope of the present invention.

[0075] Figure 1A theoretical structural schematic diagram of a secondary particle cross-section of a cathode material precursor with a composite morphology provided by the present invention;

[0076] Figure 2 Here is a cross-sectional SEM image of the precursor obtained in Example 1;

[0077] Figure 3 Here is a surface SEM image of the precursor obtained in Example 1;

[0078] Figure 4 This is a magnified SEM image of a portion of the surface of the precursor obtained in Example 1;

[0079] Figure 5 Here is a cross-sectional SEM image of the precursor obtained in Example 2;

[0080] Figure 6 Here is a surface SEM image of the precursor obtained in Example 2;

[0081] Figure 7 This is a magnified SEM image of a portion of the surface of the precursor obtained in Example 2;

[0082] Figure 8 Here is a cross-sectional SEM image of the precursor obtained in Example 3;

[0083] Figure 9 Here is a surface SEM image of the precursor obtained in Example 3;

[0084] Figure 10 This is a magnified SEM image of a portion of the surface of the precursor obtained in Example 3;

[0085] Figure 11 Here is a cross-sectional SEM image of the precursor obtained in Example 4;

[0086] Figure 12 Here is a surface SEM image of the precursor obtained in Example 4;

[0087] Figure 13 This is a magnified SEM image of a portion of the surface of the precursor obtained in Example 4;

[0088] Figure 14 Here is a cross-sectional SEM image of the precursor obtained in Comparative Example 1;

[0089] Figure 15 Here is a surface SEM image of the precursor obtained in Comparative Example 1;

[0090] Figure 16 Here is a magnified SEM image of the surface of the precursor obtained in Comparative Example 1;

[0091] Figure 17Here is a cross-sectional SEM image of the precursor obtained in Comparative Example 2;

[0092] Figure 18 Here is a surface SEM image of the precursor obtained in Comparative Example 2;

[0093] Figure 19 Here is a magnified SEM image of the surface of the precursor obtained in Comparative Example 2;

[0094] Figure 20 Here is a cross-sectional SEM image of the precursor obtained in Comparative Example 3;

[0095] Figure 21 Here is a surface SEM image of the precursor obtained in Comparative Example 3;

[0096] Figure 22 This is a magnified SEM image of the surface of the precursor obtained in Comparative Example 3. Detailed Implementation

[0097] First, the technical solution provided by this invention will be described in its entirety:

[0098] A cathode material precursor with a composite morphological structure, wherein the secondary particles of the precursor include: a core layer, an intermediate layer, and a shell layer;

[0099] The shell consists of a wider primary particle cluster A and a narrower primary particle cluster B. The primary particle cluster A is strip-shaped and multiple primary particle clusters A are arranged radially. The primary particle cluster B is located in the gap between multiple primary particle clusters A. The average width b1 of the primary particle cluster A is greater than the average width b2 of the primary particle cluster B.

[0100] A primary particle cluster refers to an indivisible aggregate of primary particles arranged in the same direction;

[0101] The method for obtaining the secondary particle cross-section of the precursor in this invention is as follows: the cross-section is obtained by cutting the powder particle sample of this invention with an ion beam, and then photographed with an electron microscope to obtain a SEM image of the cross-section.

[0102] The criteria for dividing the core, intermediate, and shell layers of a cathode material precursor cross-section are based on the morphology of each region within the cross-section. The morphology primarily includes the arrangement of primary particle clusters in the radial direction of the secondary particles. Specifically, the same primary particle cluster is classified into the same layer, and there is a gap between the shell and the intermediate layer.

[0103] Figure 1 This is a cross-sectional structural diagram of one embodiment of this application. Figure 1The criteria for dividing each layer are as follows: the central annular region with radial arrangement near the center of the secondary particles is divided into the intermediate layer; the region within the annular region is divided into the core layer; and the radially arranged region outside the annular region is divided into the shell layer.

[0104] The shell layer clearly shows two different morphologies of primary particle clusters: a wider primary particle cluster A arranged radially and a narrower primary particle cluster B. Primary particle cluster B is located within the gaps between multiple primary particle clusters A. The average width b1 of primary particle cluster A is greater than the average width b2 of primary particle cluster B. The radial arrangement of the primary particle clusters A in the precursor secondary particle shell layer facilitates the entry of lithium salts into the secondary particles through the pores of the material shell, improving capacity performance. Simultaneously, the three-layer structure of the secondary particles makes it difficult for shell cracks to extend into the particle interior, inhibiting crack growth and improving cycle performance. Multiple wider primary particle clusters A serve as a framework, while narrower primary particle clusters B fill the gaps between them, enhancing the material's structural stability, compressive strength, and compaction density. Cathode materials inheriting this structure can achieve high battery capacity while maintaining good cycle performance when fabricated into batteries.

[0105] When quantitatively measuring parameters related to primary particle clusters, the standard for selecting primary particle clusters in the cross-sectional SEM image is as follows: remove primary particle clusters with blurred edges or multiple obscurations, and select complete primary particle clusters with clear edges in the SEM image for measurement. For example, the SEM image magnification can be 3K, 5K, 9K, 10K, 15K, 20K, 25K, 30K, 40K, or 50K. The specific magnification should ideally be such that only one complete or nearly complete single secondary particle sphere cross-section is visible in the SEM field of view.

[0106] The standard for measuring the average length and average width of a primary particle cluster is as follows: the longest straight-line distance between the two ends of the selected primary particle cluster is taken as the length, and the longest straight-line distance between the two ends perpendicular to the line connecting the lengths is taken as the width. The length and width are measured using the electronic ruler software Ruler, and then the average length and average width of multiple primary particles are calculated separately. In the above measurement, if a primary particle cluster is obscured, the unobscured portion is assumed to be a complete primary particle cluster for measurement.

[0107] In one optional implementation, the cathode material precursor has a composite morphological structure:

[0108] The intermediate layer includes a wider primary particle cluster C and a narrower primary particle cluster D. The primary particle cluster C is strip-shaped and multiple primary particle clusters C are arranged radially. The primary particle cluster D is located in the gap between multiple primary particle clusters C. The average width b3 of the primary particle cluster C is greater than the average width b4 of the primary particle cluster D.

[0109] Combination Figure 1 As shown: Similar to the shell layer, the intermediate layer of the precursor secondary particles provided by this invention clearly includes two different morphologies of primary particle clusters: wider primary particle clusters C and narrower primary particle clusters D. Multiple primary particle clusters C are arranged radially, and primary particle clusters D fill the gaps between the multiple primary particle clusters C. The average width b3 of the primary particle clusters C is greater than the average width b4 of the primary particle clusters D. The radial arrangement of the primary particle clusters C in this precursor secondary particle shell layer, when used to fabricate a battery with a cathode material inheriting this structure, facilitates the entry of lithium salts through the pores of the intermediate layer into the core layer of the secondary particles, thus improving capacity performance. Meanwhile, the three-layer structure of the secondary particles makes it difficult for cracks in the middle layer to extend to the shell and core layers of the secondary particles, which can inhibit crack growth in the secondary particles and improve cycle performance. Multiple wider primary particle clusters C serve as a framework, and narrower primary particle clusters D fill the gaps between the multiple wider primary particle clusters C, which can improve the structural stability of the material, increase its compressive strength, and increase its compaction density. The cathode material that inherits this structure can maintain good cycle performance at high battery capacity after being made into a battery.

[0110] Optionally, the precursor satisfies one or more of the following conditions:

[0111] A. Primary particle clusters B are strip-shaped, and / or primary particle clusters D are strip-shaped;

[0112] Compared to spherical primary particles, strip-shaped primary particles have a larger contact area with each other, making them less prone to displacement and loosening under pressure. This inhibits the generation of secondary particle cracks, maintains the structural stability of secondary particles, and thus improves cycle performance.

[0113] B. Primary particle cluster B is arranged in a non-radiative pattern, and / or primary particle cluster D is arranged in a non-radiative pattern;

[0114] That is, the arrangement of primary particle cluster B is different from that of primary particle cluster A. If primary particle cluster A and primary particle cluster B are arranged in the same radial pattern, then primary particle cluster B cannot fill the gaps between primary particle clusters A well, and cannot provide non-radial support for primary particle clusters A. The structure is prone to deformation, which affects the stability of the secondary particle structure and ultimately cannot improve the cycle performance.

[0115] Similarly, the non-emissive form of a primary particle cluster D also has the same effect;

[0116] C. The primary particle cluster B is strip-shaped. The primary particle clusters A and B in the shell form a tree-like structure. The tree-like structure includes a trunk substructure composed of multiple primary particle clusters A and a branch substructure composed of multiple primary particle clusters B. The tree-like structure is arranged in a radial pattern.

[0117] Compared to disordered or radially distributed precursor secondary particles, when the precursor secondary particles of this invention are subjected to force, the primary particles closest to the surface of the secondary particles with the shell-like dendritic structure that are first subjected to force can quickly disperse the force to multiple adjacent primary particles in the dendritic structure, avoiding crushing themselves. This dendritic structure has high load-bearing capacity, a more reasonable force transmission path, a larger support space, and better support effect. It is not easy to break after being subjected to pressure, and the resulting cathode material has a higher compaction density, balancing battery capacity and cycle performance.

[0118] D. The average length a1 of primary particle cluster A is greater than the average length a2 of primary particle cluster B;

[0119] When primary particle cluster A serves as the skeleton, its average length is relatively long, resulting in fewer primary particle clusters A in the radial direction of the secondary particle shell. This reduces the displacement / misalignment between primary particle clusters A under pressure, improves pressure resistance, and enhances circulation. Primary particle cluster B has a shorter average length, which is beneficial for filling the gaps between multiple primary particle clusters A, resulting in better pressure resistance and improved circulation.

[0120] E. The average length a1 of primary particle cluster A is greater than the average length a3 of primary particle cluster C;

[0121] According to the principle of dividing the same primary particle cluster into the same layer, assuming that the number of primary particle clusters A in the radial direction of the secondary particle shell and the number of primary particle clusters C in the radial direction of the intermediate layer are at the same level, and the average length of primary particle cluster A is longer, then the minimum thickness of primary particle cluster A located in the shell is also correspondingly larger; the shell accounts for a large proportion of the entire secondary particle, plays a strong supporting role for the intermediate layer and the core layer, and exhibits excellent electrochemical performance.

[0122] F. The ratio of the average length a1 of primary particle cluster A to the average length a3 of primary particle cluster C is a1:a3 = (1~5):1, optionally a1:a3 = (2~4):1;

[0123] The ratio a1:a3 of the average length a1 of primary particle cluster A to the average length a3 of primary particle cluster C is calculated as follows: first calculate the average length a1 and the average length a3 of primary particle cluster C respectively, and then calculate the value of a1:a3; the calculation method of b1:b3 below can be deduced by analogy.

[0124] Optionally, the ratio a1:a3 of the average length of primary particle cluster A to the average length of primary particle cluster C can be any value between 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:4.0, 4.5:1, 5.0:1, or 1-5:1.

[0125] G. The ratio of the average width b1 of primary particle cluster A to the average width b3 of primary particle cluster C is b1:b3 = (0.2~5.0):1;

[0126] Optionally, the ratio b1:b3 of the average width b1 of primary particle cluster A to the average width b3 of primary particle cluster C can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1.4, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, or any value between 0.2 and 2.5:1;

[0127] H. The ratio of shell thickness to precursor secondary particle radius is 1:(1.2~2.5);

[0128] The Metis software developed by Beijing Oubotong Optical Technology Co., Ltd. was used to measure the core diameter, intermediate layer thickness, shell thickness, and porosity of each layer in the cross-sectional SEM image.

[0129] The measurement methods for secondary particle diameter and radius, core diameter, intermediate layer thickness, and shell thickness are as follows: In the SEM cross-sectional image of the secondary particle, the longest straight-line distance between any two endpoints on the edge of the secondary particle is considered as the secondary particle diameter; half of the secondary particle diameter is considered as the secondary particle radius; the longest straight-line distance between any two endpoints on the outer edge of the core layer is considered as the core layer diameter; the shortest straight-line distance between any point on the outer edge of the shell and any point on the inner edge of the shell is considered as the shell thickness; the intermediate layer thickness = (secondary particle diameter - core diameter - 2 × shell thickness) ÷ 2.

[0130] The method for calculating the ratio of shell thickness to precursor secondary particle radius is as follows: first calculate the ratio of shell thickness to precursor secondary particle radius in each secondary particle cross-section, and then take the range value; the calculation methods for the ratio of intermediate layer thickness to precursor secondary particle radius and the ratio of core layer diameter to precursor secondary particle diameter can be deduced by analogy.

[0131] The porosity calculation formula is as follows: Secondary particle porosity = [(sum of the areas of all visible pores inside the secondary particle in the cross section / cross section area of ​​the secondary particle) × 100] (%); Layer porosity = [(sum of the areas of all visible pores in the layer corresponding to the secondary particle in the cross section / cross section area of ​​the secondary particle) × 100] (%).

[0132] Optionally, the ratio of shell thickness to precursor secondary particle radius can be any value between 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, or 1:(1.2 to 2.5).

[0133] The radius of the precursor secondary particle is half of the maximum straight-line distance between the two endpoints of the precursor secondary particle's edge;

[0134] The shell layer accounts for a large proportion of the entire precursor secondary particles, providing strong support for the intermediate and core layers and exhibiting excellent electrochemical performance.

[0135] I. The ratio of the intermediate layer thickness to the secondary particle radius of the precursor is 1:(2.3~7.5);

[0136] Optionally, it can be any value between 1:2.3, 1:2.5, 1:3.0, 1:3.5, 1:4.0, 1:4.5, 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5 or 1:(2.3 to 7.5);

[0137] J. The ratio of the core diameter to the secondary particle diameter of the precursor is 1:(3.5~9.7);

[0138] Optionally, it can be any value between 1:3.5, 1:4.0, 1:4.5, 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5, 1:8.0, 1:8.5, 1:9.0, 1:9.5, 1:9.7, or 1:(3.5 to 9.7).

[0139] K. The shell consists of a wider primary particle cluster A and a narrower primary particle cluster B;

[0140] L. The intermediate layer consists of wider primary particle clusters C and narrower primary particle clusters D.

[0141] In one optional implementation, the cathode material precursor having a composite morphological structure satisfies one or more of the following conditions:

[0142] (1) The average length a1 of the primary particle cluster A is 2000-5000 nm; preferably, a1 is 2800-3700 nm;

[0143] Optionally, the average length a1 of the primary particle cluster A can be any value between 2000nm, 2100nm, 2200nm, 2300nm, 2400nm, 2500nm, 2600nm, 2700nm, 2800nm, 2900nm, 3000nm, 3100nm, 3200nm, 3300nm, 3400nm, 3500nm, 3600nm, 3700nm, 3800nm, 3900nm, 4000nm, 4100nm, 4200nm, 4300nm, 4400nm, 4500nm, 4600nm, 4700nm, 4800nm, 4900nm, 5000nm, or 2000-5000nm.

[0144] (2) The average width b1 of the primary particle cluster A is 50-500 nm;

[0145] Optionally, the average width b1 of the primary particle cluster A can be any value between 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, or 50-500nm.

[0146] (3) The average length a2 of the primary particle cluster B is 100-600 nm; preferably, a2 is 150-550 nm.

[0147] Optionally, the average length a2 of the primary particle cluster B is any value between 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm or 100-600nm.

[0148] (4) The average width b2 of the primary particle cluster B is 8-60 nm;

[0149] Optionally, the average width b2 of the primary particle cluster B can be any value between 8nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm or 8-60nm.

[0150] (5) The average length a3 of the primary particle cluster C is 500-2300 nm; preferably, a3 is 1000-1300 nm;

[0151] Optionally, the average length a3 of the primary particle C is any value between 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 1100nm, 1200nm, 13000nm, 1400nm, 1500nm, 1600nm, 1700nm, 1800nm, 1900nm, 2000nm, 2100nm, 2200nm, 2300nm or 500-2300nm;

[0152] (6) The average width b3 of the primary particle cluster C is 50-500 nm;

[0153] Optionally, the average width b3 of the primary particle cluster C can be any value between 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm or 100-500nm.

[0154] (7) The average length a4 of the primary particle cluster D is 100-500 nm; preferably, a4 is 140-500 nm.

[0155] Optionally, the average length a4 of the primary particle cluster D is any value between 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm or 100-500nm.

[0156] (8) The average width b4 of the primary particle cluster D is 5-55 nm;

[0157] Optionally, the average width b4 of the primary particle cluster D can be any value between 10 nm, 20 nm, 30 nm, 40 nm, 50 nm or 10-50 nm.

[0158] (9) The diameter of the core layer is 0.5-3.6 μm;

[0159] Optionally, the diameter of the core layer can be 0.5μm, 1.0μm, 1.5μm, 2.0μm, 2.5μm, 3.0μm, 3.6μm or any value between 0.5 and 3.6μm;

[0160] (10) The thickness of the intermediate layer is 0.5-2.7 μm;

[0161] Optionally, the thickness of the intermediate layer can be 0.5μm, 1.0μm, 1.5μm, 2.0μm, 2.5μm, 2.7μm or any value between 0.5 and 2.7μm;

[0162] (11) The thickness of the shell is 2.0-4.5 μm;

[0163] Optionally, the thickness of the shell can be any value between 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, or 2.0-4.5 μm;

[0164] (12) The porosity of the core layer is 15-35%;

[0165] Optionally, the porosity of the core layer can be any value between 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or 8-25%.

[0166] The core layer has high porosity and a loose structure, which is beneficial to Li + Embedding and de-embedding improve capacity performance;

[0167] (13) The porosity of the intermediate layer is 2-10%;

[0168] Optionally, the porosity of the intermediate layer can be any value between 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or 2-10%.

[0169] The intermediate layer, serving as the connecting layer between the core and shell layers, has the lowest porosity, a denser structure, better pressure resistance, and improved cycle performance.

[0170] (14) The porosity of the shell is 11-20%;

[0171] The shell has a relatively higher porosity than the middle layer. While ensuring compressive strength, the increased porosity is beneficial for Li... + It penetrates into the interior of secondary particles, maintaining high capacity performance while also ensuring good circulation performance;

[0172] Optionally, the porosity of the shell can be any value between 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or 11-20%.

[0173] (15) The secondary particle porosity of the precursor is 8-25%;

[0174] A suitable overall porosity allows secondary particles to possess a certain degree of structural strength while maintaining a certain level of porosity, thus ensuring both high capacity performance and good circulation performance.

[0175] Optionally, the secondary particle porosity of the cathode material precursor with a composite morphology can be any value between 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or between 8% and 25%.

[0176] In one optional implementation, the cathode material precursor having a composite morphological structure satisfies one or more of the following conditions:

[0177] (1) The secondary particle surface of the precursor includes two types of primary particles, namely primary particles ① and primary particles ②. Primary particles ① are located in the gaps between multiple primary particles ②.

[0178] (2) The width of primary particle ① is greater than the width of primary particle ②;

[0179] like Figure 4 and Figure 7 As shown in the SEM image of the secondary particle surface, the primary particle ① is significantly wider than the primary particle ②. The method for measuring the included angle between two intersecting primary particles ① is as follows: draw arrows along the inner edges of the two intersecting primary particle ① surfaces, use the electronic ruler software ruler to measure the acute angle, and then calculate the average angle.

[0180] (3) There is an acute angle between two intersecting primary particles ①, and the average angle of the acute angle is >30°;

[0181] Optionally, the average acute angle between two intersecting primary particles ① can be any value of >30°, >40°, >50°, >60°, >70°, >80° or >30°.

[0182] The two intersecting primary particles ① form a relatively large acute angle, and the interior is filled with primary particles ②, resulting in abundant irregular pores on the surface of the precursor secondary particles. Inheriting this structure in the cathode material facilitates the entry of lithium salts into the material's interior, improving battery capacity. Simultaneously, the primary particles ① act as a framework, with primary particles ② filling the gaps between multiple primary particles ①, making the material's surface morphology less prone to deformation and improving its structural stability. Cathode materials inheriting this structure, when fabricated into batteries, can maintain high battery capacity while also ensuring good cycle performance.

[0183] (4) The core layer is arranged in a mesh pattern;

[0184] (5) The intermediate layer covers the core layer and is arranged in a radial pattern;

[0185] (6) The shell layer covers the intermediate layer and is arranged in a radial pattern;

[0186] (7) The cathode material precursor with a composite morphological structure contains at least one metallic element selected from nickel, cobalt, and manganese; optionally, the chemical formula of the cathode material precursor with a composite morphological structure is Ni. x Co y Mn 1-x-y M a (OH)₂, wherein 0.3 < x < 0.9, 0 ≤ y ≤ 0.4, 0 ≤ a ≤ 0.1; M is one or more of Co, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb, or Sr; optionally, the chemical formula of the cathode material precursor with a composite morphology is Ni x Mn 1-x (OH)2, where 0.40 < x < 0.85.

[0187] Optionally, x can be 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, The y-values ​​are 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, or any value greater than 0.3 and less than 0.9. The y-values ​​can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0. 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40 or between 0 and 0.4 For any value, 'a' can be 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, 0.09, 0.95, 0.1, or any value between 0 and 0.1.

[0188] In one optional implementation, the cathode material precursor having a composite morphological structure satisfies one or more of the following conditions:

[0189] (1) The average particle size D50 of the cathode material precursor with composite morphology is 5.5-18.0 μm; optionally, D50 is 8.0-15.0 μm;

[0190] Optionally, the D50 of the cathode material precursor with a composite morphology can be any value between 5.5 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm, 10.0 μm, 11.0 μm, 12.0 μm, 13.0 μm, 14.0 μm, 15.0 μm, 16.0 μm, 17.0 μm, 18.0 μm, or 5.5-18.0 μm.

[0191] (2) The BET of the cathode material precursor with a composite morphological structure is 11-20m. 2 / g;

[0192] Optionally, the BET of the cathode material precursor with a composite morphological structure can be 11m. 2 / g、12m 2 / g、13m 2 / g、14m 2 / g, 15m 2 / g, 16m 2 / g、17m 2 / g、18m 2 / g、19m 2 / g、20m 2 / g or 11-20m 2 Any value between / g;

[0193] (3) The TD of the cathode material precursor with a composite morphology is 1.7-2.2 g / cm³. 3 ;

[0194] Optionally, the TD of the cathode material precursor with a composite morphology can be 1.7 g / cm³. 3 1.8g / cm 3 1.9g / cm 3 2.0g / cm 3 2.1g / cm 3 2.2g / cm 3 Or 1.7-2.2 g / cm³ 3 Any value between.

[0195] (4) The compaction density of the cathode material precursor with a composite morphology is 2.65-2.90 g / cm³ at 147.7 MPa. 3 ;

[0196] Compacted density test method: Weigh about 2g of precursor sample and place it in a cylindrical groove mold with a diameter of 13mm in a microcomputer electronic pressure testing machine for testing. Set the applied pressure to 2T. When the pressure rises from 0 to the set value of 2T (equivalent to 147.7Mpa) in 15-20 seconds, read the compacted density value on the panel and record it.

[0197] Optionally, the cathode material precursor with a composite morphology can have a compaction density of 2.65 g / cm³ at 147.7 MPa. 3 2.66 g / cm 3 2.67 g / cm 3 2.68g / cm 3 2.69 g / cm 3 2.70 g / cm 3 2.71 g / cm 3 2.72 g / cm 3 2.73 g / cm 3 2.74 g / cm 3 2.75g / cm 3 2.76 g / cm 3 2.77 g / cm 3 2.78g / cm 3 2.79 g / cm 3 2.80g / cm 3 2.81 g / cm 3 2.82 g / cm 3 2.83 g / cm 3 2.84 g / cm 3 2.85g / cm 3 2.86 g / cm 3 2.87 g / cm 3 2.88g / cm 3 2.89 g / cm 3 2.90g / cm 3 Or 2.65-2.90 g / cm³ 3 Any value between.

[0198] This invention also provides a method for preparing a cathode material precursor with a composite morphological structure, comprising:

[0199] Raw materials, including metal salt solution, precipitant, and complexing agent, are added to the first base solution to carry out the first reaction until seed crystals are obtained. During the first reaction, the flow rates of metal salt solution, precipitant, and complexing agent are controlled so that the pH value of the system continuously decreases and is then maintained within the first pH value range.

[0200] Materials including metal salt solution, precipitant, and complexing agent are added to the second base liquid to carry out the second reaction until a cathode material precursor with a composite morphology is obtained; during the second reaction, the flow rate of the precipitant is controlled so that the pH value of the system continuously decreases and is then maintained within the second pH value range.

[0201] The first base liquid includes water, a precipitant, and a complexing agent, while the second base liquid includes water, a precipitant, a complexing agent, and seed crystals.

[0202] Both the first and second reactions were carried out under isothermal conditions, with the temperature of the first reaction being 45-65℃ and the temperature of the second reaction being 40-70℃.

[0203] The mother liquor is continuously discharged during both the first and second reactions.

[0204] Optionally, the temperature of the first reaction can be any value between 45℃, 50℃, 55℃, 60℃, 65℃ or 45-65℃, and the temperature of the second reaction can be any value between 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃ or 40-70℃.

[0205] The cathode material precursor with a composite morphology provided by the present invention is obtained by using an intermittent solution coprecipitation method and adjusting various parameters.

[0206] In one optional embodiment, the method for preparing the cathode material precursor with a composite morphological structure satisfies one or more of the following conditions:

[0207] a. The molar concentration of the metal in the metal salt solution is 1.5-3.5 mol / L;

[0208] Optionally, the molar concentration of the metal in the metal salt solution can be any value between 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, or 1.5-3.5 mol / L.

[0209] b. The pH value of the first base solution is 10-12, and the ammonia concentration of the first base solution is 2-5 g / L;

[0210] ammonia concentration is NH4 + Mass fraction in solution, the same below;

[0211] Optionally, the pH value of the first base solution can be any value between 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, or 10-12. The ammonia concentration of the base solution can be any value between 2.0 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L, 3.0 g / L, 3.2 g / L, 3.4 g / L, 3.6 g / L, 3.8 g / L, 4.0 g / L, 4.2 g / L, 4.4 g / L, 4.6 g / L, 4.8 g / L, 5.0 g / L, or 2-5 g / L.

[0212] c. The pH of the second base solution is 9-11, and the ammonia concentration of the second base solution is 1.0-5.0 g / L;

[0213] Optionally, the pH value of the second substrate can be any value between 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, or 9-11, and the ammonia concentration of the second substrate can be any value between 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, or 1.0-5.0 g / L.

[0214] d. The first pH range and the second pH range are each independently 9-11;

[0215] Optionally, the first pH range and the second pH range can each be independently any value between 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, or 9-11.

[0216] e. The average seed crystal diameter D50 is 1-5 μm;

[0217] Optionally, the average seed size D50 can be any value between 1 μm, 2 μm, 3 μm, 4 μm, 5 μm or 1-5 μm;

[0218] f. In the first reaction, the flow rate of the metal salt solution is 1-6% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-2.22% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-0.50% / h of the reaction vessel volume.

[0219] Optionally, the flow rate of the metal salt solution can be any value between 1% / h, 2% / h, 3% / h, 4% / h, 5% / h, 6% / h, or 1-6% / h of the reaction vessel volume, and the flow rate of the precipitant can be any value between 0.35% / h, 0.57% / h, 0.77% / h, 0.97% / h, 1.07% / h, 1.17% / h, 1.27% / h, 1.37% / h, 1.47% / h, 1.57% / h, 1.67% / h, 1.77% / h, and 1.87% / h of the reaction vessel volume. The concentrations of the complexing agent are 1.97%, 2.07%, 2.17%, 2.22%, or any value between 0.35% and 2.22% / h, and the flow rate of the complexing agent is any value between 0.01%, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, or any value between 0.01% and 0.50% / h of the reaction vessel volume.

[0220] g. In the second reaction, the flow rate of the metal salt solution is 1.0-10.0% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-3.7% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-1.00% / h of the reaction vessel volume.

[0221] Optionally, in the second reaction, the flow rate of the metal salt solution is any value between 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% of the reaction vessel volume, or 1.0-10.0% of the reaction vessel volume, and the flow rate of the precipitant is 0.35%, 0.57%, 0.77%, or 0.8% of the reaction vessel volume. 0.97% / h, 1.07% / h, 1.17% / h, 1.27% / h, 1.37% / h, 1.47% / h, 1.57% / h, 1.67% / h, 1.7 7% / h, 1.87% / h, 1.97% / h, 2.07% / h, 2.17% / h, 2.27% / h, 2.37% / h, 2.47% / h, 2.57% / h The concentrations of the complexing agent can be any value between 2.67% / h, 2.77% / h, 2.87% / h, 2.97% / h, 3.07% / h, 3.17% / h, 3.27% / h, 3.37% / h, 3.47% / h, 3.57% / h, 3.70% / h, or 0.35-3.7% / h, with the flow rate of the complexing agent being 0.01% / h or 0.05% of the reaction vessel volume. / h, 0.10% / h, 0.15% / h, 0.20% / h, 0.25% / h, 0.30% / h, 0.35% / h, 0.40% / h, 0.45% / h, 0.50% / h, 0.60% / h, 0.70% / h, 0.80% / h, 0.90% / h, 1.00% / h, or any value between 0.01% and 1.00% / h;

[0222] h. Both the first and second reactions are carried out under stirring conditions, with stirring speeds of 100-400 r / min for each reaction independently.

[0223] Optionally, the stirring speeds for the first and second reactions can be independently set to 100 r / min, 200 r / min, 300 r / min, 400 r / min, or any value between 100 and 400 r / min.

[0224] The present invention also provides a lithium-ion battery cathode material, wherein the raw materials of the lithium-ion battery cathode material include a cathode material precursor having a composite morphological structure.

[0225] The present invention also provides a lithium-ion battery, including a lithium-ion battery positive electrode material.

[0226] The present invention also provides an electrical device, including a lithium-ion battery.

[0227] The electrical equipment referred to in this invention refers to equipment that directly or indirectly uses the lithium-ion battery provided by this invention, such as electric vehicles, electric bicycles, etc.

[0228] The lithium-ion battery cathode material, lithium-ion battery, and electrical equipment provided by this invention have excellent electrical performance while maintaining high capacity and cycle performance.

[0229] The embodiments of the present invention will be described in detail below with reference to specific 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 products.

[0230] Example 1

[0231] This embodiment provides a cathode material precursor with a composite morphological structure, and its preparation method is as follows:

[0232] Step 1: Weigh and calculate nickel sulfate, cobalt sulfate, and manganese sulfate, and prepare a metal salt solution with a total metal molar weight of 2 mol / L according to the metal molar ratio of nickel:cobalt:manganese = 75:1:24; prepare a 32.5% sodium hydroxide solution; and prepare a 20.5% ammonia solution.

[0233] Step 2: Add pure water, sodium hydroxide solution, and ammonia water to reactor #1 and stir at 220 rpm until homogeneous. Maintain a constant temperature of 55°C to obtain a first base solution with a pH of 11.4 and an ammonia concentration of 4.0 g / L. Simultaneously introduce the metal salt solution, sodium hydroxide solution, and ammonia water into reactor #1 at flow rates of 1%, 0.35%, and 0.03% of the reactor volume, respectively, while stirring at 220 rpm and maintaining a constant temperature of 60°C. After the reaction and precipitation begin, adjust the flow rate of the sodium hydroxide solution to lower the pH value, ultimately maintaining the first pH range at 10.6-10.8. During the reaction, discharge the mother liquor through a concentration device at a rate consistent with the total feed rate until a seed slurry with a medium particle size D50 of 5 μm is obtained. After dehydration, obtain the seed crystals.

[0234] Step 3: The seed crystals obtained in Step 2 are added to Reactor #2, along with water, sodium hydroxide solution, and ammonia. The mixture is stirred at 220 rpm until homogeneous, yielding a second base solution with a pH of 10.7 and an ammonia concentration of 3.2 g / L. The metal salt solution, sodium hydroxide solution, and ammonia are simultaneously introduced into Reactor #2 at flow rates of 1%, 0.35%, and 0.03% of the reactor volume, respectively. The temperature is maintained at 65°C. After precipitation begins, the pH is lowered by adjusting the flow rate of the sodium hydroxide solution, ultimately maintaining the second pH range between 10.4 and 10.6. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0235] Step 4: After washing, centrifuging, drying, and demagnetizing the product slurry, the ternary high-nickel product Ni with the composite structure is obtained. 0.75 Co 0.01 Mn 0.24 (OH)2; SEM image of cross section as follows Figure 2 As shown, it has a three-layer structure, with both the shell and middle layers being composites of two types of primary particle clusters. The surface SEM image is shown below. Figure 3 As shown. A magnified partial SEM image of the surface is shown below. Figure 4 As shown, the average acute angle between intersecting particles ① is >30°.

[0236] Example 2

[0237] This embodiment provides a cathode material precursor with a composite morphological structure, and its preparation method is as follows:

[0238] Step 1: Weigh and calculate nickel sulfate and manganese sulfate, and prepare a metal salt solution with a total metal molar amount of 2 mol / L according to the metal molar ratio of nickel:manganese = 50:50; prepare a 32.5% sodium hydroxide solution; prepare a 20.5% ammonia solution.

[0239] Step 2: Add pure water, sodium hydroxide solution, and ammonia water to reactor #1 and stir at 220 rpm until homogeneous. Maintain a constant temperature of 55°C to obtain a first base solution with a pH of 11.0 and an ammonia concentration of 2.5 g / L. Simultaneously introduce the metal salt solution, sodium hydroxide solution, and ammonia water into reactor #1 at flow rates of 4%, 1.48%, and 0.06% of the reactor volume, respectively, while maintaining a constant temperature of 55°C. After the reaction and precipitation begin, adjust the flow rate of the sodium hydroxide solution to lower the pH value, ultimately maintaining the first pH value range at 9.7-9.9. During the reaction, discharge the mother liquor through a concentration device at a rate consistent with the total feed rate until a seed slurry with a medium particle size D50 of 3 μm is obtained. After dehydration, the seed crystals are obtained.

[0240] Step 3: Add the seed crystals obtained in Step 2 to Reactor #2, along with water, sodium hydroxide solution, and ammonia. Stir at 220 rpm until homogeneous, obtaining a second base solution with a pH of 10.1 and an ammonia concentration of 3.5 g / L. Continue to simultaneously introduce the metal salt solution, sodium hydroxide solution, and ammonia into Reactor #2 at flow rates of 1%, 0.32%, and 0.03% of the reactor volume, respectively. Maintain a constant temperature of 50°C. After precipitation begins, adjust the flow rate of the sodium hydroxide solution to lower the pH value, ultimately maintaining the second pH range between 9.6 and 9.8. During the reaction, discharge the mother liquor through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0241] Step 4: After washing, centrifuging, drying, and demagnetizing the product slurry, the cobalt-free nickel-containing product Ni with this composite structure is obtained. 0.50 Mn 0.50 (OH)2. SEM image of the cross section as shown. Figure 5 As shown, it has a three-layer structure. The middle layer and the shell are both composites of two types of primary particle clusters. The shell has a dendritic morphology, with primary particle clusters A and B forming the dendritic structure. The dendritic structure includes a trunk substructure composed of multiple primary particle clusters A and a branch substructure composed of multiple primary particle clusters B. The dendritic structure is arranged in a radial pattern. Surface SEM image is shown below. Figure 6 As shown, a magnified partial SEM image of the surface is as follows. Figure 7 As shown, the average acute angle between intersecting particles ① is >30°.

[0242] Example 3

[0243] Compared with Example 1, the difference in this embodiment is that in step 1: nickel sulfate, cobalt sulfate, manganese sulfate, and aluminum sulfate are calculated and weighed, and a metal salt solution with a total metal molar amount of 2 mol / L is prepared according to the metal molar ratio of nickel:cobalt:manganese:aluminum = 50:20:29:1.

[0244] Ni, a composite structure doped aluminum quaternary nickel product, was obtained. 0.50 Co 0.20 Mn 0.29 Al 0.01 (OH)2; SEM image of cross section as follows Figure 8 As shown, it has a three-layer structure, with the shell and middle layers being composites of two primary particle clusters; compared to Examples 1-2, primary particle clusters A and C are thinner. Surface SEM images are shown below. Figure 9 As shown. A magnified partial SEM image of the surface is shown below. Figure 10 As shown, the average angle of the acute angle between intersecting particles ① is >30°.

[0245] Example 4

[0246] Compared with Example 1, the difference in this embodiment lies in step 2: pure water, sodium hydroxide solution, and ammonia water are added to reactor #1 and stirred at 220 r / min until homogeneous, while maintaining a constant temperature of 55°C, resulting in a first base solution with a pH of 11.4 and an ammonia concentration of 4.0 g / L. Metal salt solution, sodium hydroxide solution, and ammonia water are simultaneously introduced into reactor #1 at flow rates of 1%, 0.35%, and 0.03% of the reactor volume, respectively, while stirring at 220 r / min and maintaining a constant temperature of 60°C. After the reaction and precipitation begin, the pH value is lowered by adjusting the flow rate of the sodium hydroxide solution, ultimately maintaining the first pH value range at 10.6-10.8. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate, until a seed slurry with a medium particle size D50 of 3 μm is obtained. After dehydration, seed crystals are obtained.

[0247] Step 3: The seed crystals obtained in Step 2 are added to Reactor #2, along with water, sodium hydroxide solution, and ammonia, to obtain a second base solution with a pH of 10.1 and an ammonia concentration of 3.5 g / L. The metal salt solution, sodium hydroxide solution, and ammonia are simultaneously introduced into the reactor at flow rates of 1%, 0.35%, and 0.03% of the reactor volume, respectively, at a constant temperature of 50°C. After precipitation begins, the pH is lowered by adjusting the flow rate of the sodium hydroxide solution, maintaining the final second pH value within the range of 9.7-9.9. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0248] Ni, a cobalt-free nickel product with this composite structure, was obtained. 0.50 Mn 0.50 (OH)2; SEM image of cross section as follows Figure 11 As shown, it has a three-layer structure, with the shell and middle layers being composites of two types of primary particle clusters. Compared to Examples 1-3, primary particle clusters A and C are coarser. Surface SEM images are shown below. Figure 12 As shown. A magnified partial SEM image of the surface is shown below. Figure 13 As shown, the average angle of the acute angle between intersecting particles ① is >30°.

[0249] Comparative Example 1

[0250] The difference between this comparative example and Example 1 lies in step 3: the seed crystals obtained in step 2 are added to reactor #2, along with water, sodium hydroxide solution, and ammonia, to obtain a second base solution with a pH of 10.1 and an ammonia concentration of 3.5 g / L. The metal salt solution, sodium hydroxide solution, and ammonia are then simultaneously introduced into the reactor at flow rates of 1% / h, 0.35% / h, and 0.03% / h of the reactor volume, respectively. The temperature is maintained at 60°C. After precipitation begins, the pH is lowered by adjusting the flow rate of the sodium hydroxide solution, ultimately maintaining the pH between 9.1 and 9.4. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0251] Ni, a cobalt-free nickel product with this composite structure, was obtained. 0.50 Mn 0.50 (OH)2; SEM image of cross section as follows Figure 14 As shown, it has a two-layer structure. The primary particles in both the shell and core layers are short, needle-like. The primary particles in the core layer are randomly arranged, while those in the shell layer are radially arranged. The surface SEM image is shown below. Figure 15 As shown. A magnified partial SEM image of the surface is shown below. Figure 16 As shown.

[0252] Comparative Example 2

[0253] The difference between this comparative example and Example 1 lies in step 3: the seed crystals obtained in step 2 are added to reactor #2, along with water, sodium hydroxide solution, and ammonia, to obtain a second base solution with a pH of 10.5 and an ammonia concentration of 3.5 g / L. The metal salt solution, sodium hydroxide solution, and ammonia are then simultaneously introduced into the reactor at flow rates of 1% / h, 0.35% / h, and 0.03% / h of the reactor volume, respectively. The temperature is maintained at 50°C. After precipitation begins, the pH is maintained between 10.0 and 10.2 by adjusting the flow rate of the sodium hydroxide solution. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0254] Ni, a cobalt-free nickel product with this composite structure, was obtained. 0.50 Mn 0.50 (OH)2; SEM image of cross section as follows Figure 17 As shown, it has a two-layer structure. The shell is a composite of two types of primary particle clusters, with only a small number of thin primary particle clusters filling the spaces between the coarse, elongated primary particle clusters. The surface SEM image is shown below. Figure 18 As shown. A magnified partial SEM image of the surface is shown below. Figure 19 As shown, the average angle of the acute angle between intersecting particles ① is <30°.

[0255] Comparative Example 3

[0256] Compared with Example 1, this comparative example differs in step 2, where pure water, sodium hydroxide solution, and ammonia are added to reactor #1 and stirred at 220 rpm until homogeneous, maintaining a constant temperature of 55°C, resulting in a first base solution with a pH of 11.4 and an ammonia concentration of 4.0 g / L. Metal salt solution, sodium hydroxide solution, and ammonia are simultaneously introduced into reactor #1 at flow rates of 1%, 0.35%, and 0.03% of the reactor volume, respectively, while stirring at 220 rpm and maintaining a constant temperature of 60°C. After precipitation begins, the pH is lowered by adjusting the flow rate of the sodium hydroxide solution, ultimately maintaining the first pH range between 10.6 and 10.8. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate, until a seed slurry with a medium particle size D50 of 4 μm is obtained. After dehydration, seed crystals are obtained.

[0257] Step 3: The seed crystals obtained in Step 2 are added to Reactor #2, along with water, sodium hydroxide solution, and ammonia, to obtain a second base solution with a pH of 10.1 and an ammonia concentration of 3.5 g / L. The metal salt solution, sodium hydroxide solution, and ammonia are simultaneously introduced into Reactor #2 at flow rates of 1% / h, 0.35% / h, and 0.03% / h of the reactor volume, respectively. The temperature is maintained at 50°C. After the reaction and precipitation begin, the pH is maintained at 10.1 for the first 10 hours by adjusting the sodium hydroxide solution flow rate. After 10 hours, the sodium hydroxide solution flow rate is adjusted to decrease the pH by 0.1, ultimately maintaining the pH between 9.9 and 10.1. During the reaction, the mother liquor is discharged through a concentration device at a rate consistent with the total feed rate until a product slurry is obtained.

[0258] Ni, a cobalt-free nickel product with this composite structure, was obtained. 0.50 Mn 0.50 (OH)2; SEM image of cross section as follows Figure 20 As shown, it has a three-layer structure. Both the shell and the middle layer are composite structures of two types of primary particle clusters. In the shell, only a very small number of fine, strip-shaped primary particle clusters fill the gaps between the coarse, elongated primary particle clusters. The surface SEM image is shown below. Figure 21 As shown, a magnified partial SEM image of the surface is as follows. Figure 22 As shown, the average acute angle between intersecting particles ① is <30°.

[0259] Cathode material preparation:

[0260] 2000g of the precursors prepared in Examples 1-4 and Comparative Examples 1-3 and LiOH were mixed uniformly in a molar ratio of 1:1.05 using a high-speed mixer. The mixture was then sintered in an air atmosphere using a box furnace at a sintering temperature of 950℃ for 12 hours. After cooling to room temperature, the cathode material was obtained.

[0261] Battery fabrication:

[0262] Electrochemical performance testing was conducted using a button cell battery: The above-mentioned positive electrode material, conductive carbon black, and binder PVDF (polyvinylidene fluoride) were mixed into a slurry according to a certain ratio, and coated onto aluminum foil to form the positive electrode sheet. A lithium metal sheet was used as the negative electrode sheet, and a 1 mol / L LiPF6:EC:DMC electrolyte (volume ratio 1:1:1) was used. The battery casing, positive and negative electrodes, separator, spring contacts, and gaskets were assembled into a button cell battery in a vacuum glove box. Electrochemical performance testing was conducted using a blue electrode testing system at 25℃ and 3.0-4.3V, with 1C = 200 mAh / g.

[0263] The obtained data is shown in Table 1-6 below:

[0264] Table 1. Physicochemical data of precursor products obtained from each embodiment and comparative example.

[0265]

[0266] Table 2. Morphology of secondary particle cross-sections of precursor products obtained in each embodiment and comparative example.

[0267]

[0268] Table 3. Secondary particle cross-sectional area data of precursor products prepared in each embodiment and comparative example.

[0269]

[0270] Table 4. Cross-sectional data of precursor products obtained in each embodiment and comparative example.

[0271]

[0272] Table 5. Cross-sectional data of precursor products obtained from each embodiment and comparative example.

[0273]

[0274] Table 6 Electrochemical data for each example and comparative example

[0275] Serial Number Molecular formula 0.1C discharge capacity (mAh / g) 0.5C 50-week cycle retention rate (%) Example 1 <![CDATA[Ni 0.75 What 0.01 Mn 0.24 (OH)2]]> 216 96.4 Example 2 <![CDATA[Ni 0.50 Mn 0.50 (OH)2]]> 218 97.3 Example 3 <![CDATA[Ni 0.50 What 0.20 Mn 0.29 Al 0.01 (OH)2]]> 215 96.9 Example 4 <![CDATA[Ni0.50Mn 0.50 (OH)2]]> 211 97.8 Comparative Example 1 <![CDATA[Ni 0.50 Mn 0.50 (OH)2]]> 223 91.1 Comparative Example 2 <![CDATA[Ni 0.50 Mn 0.50 (OH)2]]> 208 96.7 Comparative Example 3 <![CDATA[Ni0.50Mn0.50(OH)2]]> 206 95.6

[0276] Comparing the above Examples 1-4 and Comparative Examples 1-3, the following conclusions can be drawn:

[0277] Example 1 is a low-cobalt, medium-high nickel nickel-cobalt-manganese hydroxide Ni 0.75 Co 0.01 Mn 0.24(OH)2 has a three-layer structure: a core layer, an intermediate layer, and a shell layer. The shell layer has a composite morphology of two primary particles. The primary particle clusters A in the shell layer are radial. When cathode materials with this structure are used to make batteries, it is more conducive for lithium salts to enter the interior of the secondary particles through the pores of the material shell layer, thus improving capacity performance. At the same time, the three-layer structure of the secondary particles makes it difficult for shell cracks to extend into the interior of the secondary particles, which can inhibit crack growth in the secondary particles and improve cycle performance. Multiple wider primary particle clusters A serve as a framework, while narrower primary particle clusters B fill the gaps between the multiple wider primary particle clusters A, which can improve the structural stability of the material, strengthen its compressive strength, and increase its compaction density. Cathode materials with this structure can maintain good cycle performance while achieving high battery capacity when used to make batteries.

[0278] Compared to Example 1, Example 2 is a cobalt-free, medium-nickel nickel-manganese hydroxide Ni 0.50 Mn 0.50 (OH)2 has a three-layer internal structure, with a dendritic shell and high porosity. Cathode materials inheriting this structure, when fabricated into batteries, facilitate the entry of lithium salts into the core layer, resulting in a higher 0.1C discharge capacity compared to Example 1. Furthermore, the product prepared in Example 2, despite having a higher shell porosity than Example 1, still exhibits a higher compaction density. Cathode materials inheriting this structure, when fabricated into batteries, demonstrate a higher 0.5C 50-cycle cycle retention rate, indicating that the dendritic structure exhibits greater compressive strength.

[0279] Compared to Example 1, Example 3 is a nickel-cobalt-manganese-aluminum hydroxide (Ni) doped with aluminum and containing medium nickel. 0.50 Co 0.20 Mn 0.29 Al 0.01 (OH)2; the internal structure is three-layered. From the morphology, the two forms of primary particles in Example 3 are basically similar to those in Example 1. Aluminum doping can improve the cycle performance; however, aluminum does not contribute to the capacity, so the capacity is slightly reduced.

[0280] Compared to Example 1, Example 4 is a cobalt-free, medium-nickel nickel-manganese hydroxide Ni 0.50 Mn 0.50 (OH)2, wherein the primary particle clusters A and B in the shell are wider than those in Example 1, have higher structural strength, higher compaction density, and higher retention rate in 0.5C50 cycles compared to Example 1; however, the shell porosity is lower than that in Example 1, indicating slightly poorer capacity performance.

[0281] The product obtained in Comparative Example 1 consists of short, needle-shaped primary particles, which are more porous than those in Example 1. The secondary particles have high porosity, and the cathode material inheriting this structure exhibits a higher 0.1C discharge capacity after being fabricated into a battery. However, the primary particles are easily broken, and there is no wider primary particle cluster A as a skeleton structure to support the secondary particles as in Example 1. The compaction density is low, and the structural stability is poor. The cathode material inheriting this structure exhibits poor cycle performance after being fabricated into a battery, which has a significant impact on the product's range and lifespan.

[0282] The product obtained in Comparative Example 2 has a two-layer internal structure with a dense internal structure, very low secondary particle porosity, and good structural stability. The cathode material inheriting this structure, after being made into a battery, has a cycle performance that is not much different from that in Example 1. However, this relatively dense precursor material makes it difficult for lithium salt to enter the precursor for a full reaction. The cathode material inheriting this structure exhibits poor capacity performance after being made into a battery.

[0283] The product obtained in Comparative Example 3 has a three-layer structure. The shell layer is composed of composite primary particles, with only a very small number of fine strip-shaped primary particles filling the gaps between coarse strip-shaped primary particles. The coarse strip-shaped primary particles are relatively wide, and the included angle between two intersecting coarse strip-shaped primary particles is less than 30°. The porosity of the secondary particles is low. The cathode material inheriting this structure exhibits poor capacity performance after being made into a battery.

[0284] 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; and these 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 cathode material precursor with a composite morphological structure, characterized in that, The secondary particles of the precursor include: a core layer, an intermediate layer, and a shell layer; The shell includes a wider primary particle cluster A and a narrower primary particle cluster B, wherein the average length a1 of the primary particle cluster A is greater than the average length a2 of the primary particle cluster B; the primary particle cluster A is strip-shaped, and multiple primary particle clusters A are arranged in a radial pattern, and the primary particle cluster B is located in the gap between the multiple primary particle clusters A. The chemical formula of the cathode material precursor with a composite morphological structure is Ni. x Co y Mn 1-x-y M a (OH)2, wherein 0.3 < x < 0.9, 0 ≤ y ≤ 0.4, 0 ≤ a ≤ 0.1; and M is one or more of Co, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb or Sr.

2. The cathode material precursor with a composite morphological structure according to claim 1, characterized in that, The intermediate layer includes a wider primary particle cluster C and a narrower primary particle cluster D. The primary particle cluster C is strip-shaped, and multiple primary particle clusters C are arranged in a radial pattern. The primary particle cluster D is located in the gap between the multiple primary particle clusters C.

3. The cathode material precursor with a composite morphological structure according to claim 2, characterized in that, The precursor satisfies one or more of the following conditions: A. The primary particle cluster B is strip-shaped, and / or the primary particle cluster D is strip-shaped; B. The primary particle cluster B is arranged in a non-radiative pattern, and / or the primary particle cluster D is arranged in a non-radiative pattern; C. The primary particle cluster B is strip-shaped, and the primary particle clusters A and B of the shell form a tree-like structure, which includes a trunk substructure composed of multiple primary particle clusters A and a branch structure composed of multiple primary particle clusters B; E. The average length a1 of the primary particle cluster A is greater than the average length a3 of the primary particle cluster C. F. The ratio of the average length a1 of the primary particle cluster A to the average length a3 of the primary particle cluster C is a1:a3 = (1~5):1; G. The ratio of the average width b1 of the primary particle cluster A to the average width b3 of the primary particle cluster C is b1:b3 = (0.2~2.5):1; H. The ratio of the shell thickness to the radius of the precursor secondary particles is 1:(1.2~2.5); I. The ratio of the thickness of the intermediate layer to the radius of the secondary particles of the precursor is 1:(2.3~7.5); J. The ratio of the core layer diameter to the secondary particle diameter of the precursor is 1:(3.5~9.7). K. The shell is composed of a wider primary particle cluster A and a narrower primary particle cluster B; L. The intermediate layer consists of wider primary particle clusters C and narrower primary particle clusters D.

4. The cathode material precursor with a composite morphological structure according to claim 3, characterized in that, The ratio of the average length a1 of the primary particle cluster A to the average length a3 of the primary particle cluster C is a1:a3 = (2~4):

1.

5. The cathode material precursor with a composite morphological structure according to claim 2, characterized in that, One or more of the following conditions must be met: (1) The average length a1 of the primary particle cluster A is 2000-5000 nm; (2) The average width b1 of the primary particle cluster A is 50-500 nm; (3) The average length a2 of the primary particle cluster B is 100-600 nm; (4) The average width b2 of the primary particle cluster B is 8-60 nm; (5) The average length a3 of the primary particle cluster C is 500-2300 nm; (6) The average width b3 of the primary particle cluster C is 50-500 nm; (7) The average length a4 of the primary particle cluster D is 100-500 nm; (8) The average width b4 of the primary particle cluster D is 5-55 nm; (9) The diameter of the core layer is 0.5-3.6 μm; (10) The thickness of the intermediate layer is 0.5-2.7 μm; (11) The thickness of the shell is 2.0-4.5 μm; (12) The porosity of the core layer is 15-35%; (13) The porosity of the intermediate layer is 2-10%; (14) The porosity of the shell is 11-20%; (15) The secondary particle porosity of the precursor is 8-25%.

6. The cathode material precursor with a composite morphological structure according to claim 5, characterized in that, One or more of the following conditions must be met: (1) The average length a1 of the primary particle cluster A is 2800-3700 nm; (2) The average length a2 of the primary particle cluster B is 150-550 nm; (3) The average length a3 of the primary particle cluster C is 1000-1300 nm; (4) The average length a4 of the primary particle cluster D is 140-500 nm.

7. The cathode material precursor with a composite morphological structure according to claim 1, characterized in that, One or more of the following conditions must be met: (1) The secondary particle surface of the precursor includes two types of primary particles, namely primary particles ① and primary particles ②, wherein the primary particles ① are located in the gap between multiple primary particles ②; (2) The width of the primary particle ① is greater than the width of the primary particle ②; (3) There is an acute angle between the two intersecting primary particles ①, and the average angle of the acute angle is >30°; (4) The core layer is arranged in a mesh pattern; (5) The intermediate layer covers the core layer and is arranged in a radial pattern; (6) The shell layer covers the intermediate layer and is arranged in a radial pattern; (7) The chemical formula of the cathode material precursor with the composite morphology is Ni x Mn 1-x (OH)2, where 0.40 < x < 0.

85.

8. The cathode material precursor with a composite morphological structure according to any one of claims 1-7, characterized in that, One or more of the following conditions must be met: (1) The average particle size D50 of the cathode material precursor with the composite morphology structure is 5.5-18.0 μm; (2) The BET of the cathode material precursor with the composite morphology is 11-20m. 2 / g; (3) The TD of the cathode material precursor with the composite morphology is 1.7-2.2 g / cm³. 3 ; (4) The cathode material precursor with the composite morphology has a compaction density of 2.65-2.90 g / cm³ at 147.7 MPa. 3 .

9. The cathode material precursor with a composite morphological structure according to any one of claims 1-7, characterized in that, The average particle size D50 of the cathode material precursor with the composite morphology is 8.0-15.0 μm.

10. A method for preparing a cathode material precursor with a composite morphological structure as described in any one of claims 1-9, characterized in that, include: Raw materials, including metal salt solution, precipitant, and complexing agent, are added to the first base solution to carry out the first reaction until seed crystals are obtained. During the first reaction process, the flow rates of the metal salt solution, the precipitant, and the complexing agent are controlled so that the pH value of the system continuously decreases and is then maintained within the first pH value range. Materials including the metal salt solution, the precipitant, and the complexing agent are added to a second base liquid to carry out a second reaction until the cathode material precursor with the composite morphology is obtained; during the second reaction, the flow rate of the precipitant is controlled so that the pH value of the system continuously decreases and is then maintained within a second pH value range. The first base liquid comprises water, the precipitant, and the complexing agent, and the second base liquid comprises water, the precipitant, the complexing agent, and the seed crystals. Both the first reaction and the second reaction are carried out under isothermal conditions, with the first reaction temperature being 45-65℃ and the second reaction temperature being 40-70℃. The mother liquor was continuously discharged during both the first and second reactions.

11. The method for preparing a cathode material precursor with a composite morphological structure according to claim 10, characterized in that, One or more of the following conditions must be met: a. The molar concentration of the metal in the metal salt solution is 1.5-3.5 mol / L; b. The pH value of the first base solution is 10-12, and the ammonia concentration of the first base solution is 2-5 g / L; c. The pH value of the second substrate is 9-11, and the ammonia concentration of the second substrate is 1.0-5.0 g / L; d. The first pH range and the second pH range are each independently 9-11; e. The average grain size D50 of the seed crystals is 1-5 μm; f. In the first reaction, the flow rate of the metal salt solution is 1-6% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-2.22% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-0.50% / h of the reaction vessel volume; g. In the second reaction, the flow rate of the metal salt solution is 1.0-10.0% / h of the reaction vessel volume, the flow rate of the precipitant is 0.35-3.7% / h of the reaction vessel volume, and the flow rate of the complexing agent is 0.01-1.0% / h of the reaction vessel volume; h. Both the first and second reactions are carried out under stirring conditions, and the stirring speeds for the first and second reactions are independently 100-400 r / min.

12. A lithium-ion battery cathode material, characterized in that, The raw materials for the lithium-ion battery cathode material include the cathode material precursor with a composite morphological structure as described in any one of claims 1-9.

13. A lithium-ion battery, characterized in that, Including the lithium-ion battery cathode material as described in claim 12.

14. An electrical-related device, characterized in that, Including the lithium-ion battery as described in claim 13.

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