Positive electrode material precursor and preparation method therefor, positive electrode material, battery, and electric device

Abstract

The present disclosure relates to the field of batteries, and provides a positive electrode material precursor and a preparation method therefor, a positive electrode material, a battery, and an electric device. The positive electrode material precursor comprises first-class secondary particles and second-class secondary particles, wherein the section of the first-class secondary particle has a radial structure, and the section has a porosity of 2-7%; and the section of the second-class secondary particle has a non-radial structure, and the section has a porosity of 5-12%. The positive electrode material precursor provided in the present disclosure has high rate performance, relatively strong cycling stability, and relatively high discharge capacity.

Description

Positive electrode material precursor and preparation method thereof, positive electrode material, battery and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to application number 2024101360116 filed with the Patent Office of China on January 30, 2024, entitled “Positive electrode material precursor and preparation method thereof, positive electrode material, battery and electrical-related equipment,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of lithium-ion batteries, and in particular to a cathode material precursor and a preparation method thereof, a cathode material, a battery, and electrical equipment. Background Art

[0004] As a front-end product of ternary lithium-ion battery positive electrode materials, the ternary precursor is highly customized and standardized, reflecting the inseparable relationship between its physical and chemical indicators and the physical and chemical properties and electrochemical properties of the positive electrode materials.

[0005] At present, in the field of new energy vehicles, some terminal applications pay more attention to characteristics such as high energy density, high capacity and safety performance. Since the positive electrode material has a certain inheritance of the characteristics of the precursor, it is necessary to design from the perspective of the precursor to provide a precursor that can meet both high specific capacity and high safety and high rate performance, while also having high energy density.

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

[0007] The purpose of the present disclosure is to provide a positive electrode material precursor and a preparation method thereof, a positive electrode material, a battery and electrical equipment to solve the above problems.

[0008] To achieve the above objectives, the present disclosure adopts the following technical solutions:

[0009] A positive electrode material precursor includes a first type of secondary particles and a second type of secondary particles. The cross-section of the first type of secondary particles is a radial structure with a porosity of 2%-7%. The cross-section of the second type of secondary particles is a non-radial structure with a porosity of 5%-12%.

[0010] Optionally, the average particle size of the first type of secondary particles is greater than the average particle size of the second type of secondary particles.

[0011] Optionally, the primary particles of the first type of secondary particles are spindle-shaped.

[0012] Optionally, the average length of the primary particles of the first type of secondary particles is 200-800 nm.

[0013] Optionally, the average width of the primary particles of the first type of secondary particles is 80-200 nm.

[0014] Optionally, the average aspect ratio of the primary particles of the first type of secondary particles is (2-10):1.

[0015] Optionally, the average length of the primary particles of the first type of secondary particles is 400-650 nm.

[0016] Optionally, the average width of the primary particles of the first type of secondary particles is 100-150 nm.

[0017] Optionally, the average aspect ratio of the primary particles of the first type of secondary particles is (3-6):1.

[0018] Optionally, the primary particles of the second type of secondary particles are in block shape.

[0019] Optionally, the average length of the primary particles of the second type of secondary particles is 500-1000 nm.

[0020] Optionally, the average width of the primary particles of the second type of secondary particles is 50-300 nm.

[0021] Optionally, the average aspect ratio of the primary particles of the second type of secondary particles is (2-8):1.

[0022] Optionally, the average length of the primary particles of the second type of secondary particles is 700-1000 nm.

[0023] Optionally, the average width of the primary particles of the second type of secondary particles is 150-300 nm.

[0024] Optionally, the average aspect ratio of the primary particles of the second type of secondary particles is (3-5):1.

[0025] Optionally, the cathode material precursor meets one or more of the following conditions:

[0026] a. The particle size D50 of the cathode material precursor is 7.5-20 μm, optionally 10-20 μm;

[0027] b. The specific surface area of ​​the cathode material precursor is 5-15m 2 / g, optional 8-12m 2 / g;

[0028] c. The tap density TD of the positive electrode material precursor is not less than 2.2 g / cm 3 .

[0029] Optionally, the mass ratio of the first type of secondary particles to the second type of secondary particles is (1-6):1, optionally (2-6):1.

[0030] Optionally, the cathode material precursor is a hydroxide containing a transition metal.

[0031] Optionally, the transition metal-containing hydroxide contains Ni, and optionally contains Co and / or Mn.

[0032] Optionally, the chemical formula of the positive electrode material precursor is Ni x Co y Mn z M a (OH)2, wherein 0.50≤x<1.0, 0≤y≤0.50, 0≤z≤0.50, x+y+z=1, M includes one or more of Al, Ti, Mg, Zr, W and Zn, and 0≤a≤0.20.

[0033] The present disclosure also provides a method for preparing the positive electrode material precursor, comprising:

[0034] obtaining the first type of secondary particles and the second type of secondary particles respectively;

[0035] The first type of secondary particles and the second type of secondary particles are mixed to obtain the positive electrode material precursor.

[0036] The present disclosure also provides a positive electrode material, the raw materials of which include the positive electrode material precursor.

[0037] The present disclosure also provides a battery comprising the positive electrode material.

[0038] The present disclosure also provides an electrical device, comprising the battery.

[0039] Compared with the prior art, the advantages of the present invention include:

[0040] The positive electrode material precursor provided by the present invention includes a first type of secondary particles and a second type of secondary particles, and the average particle size of the first type of secondary particles is larger than the average particle size of the second type of secondary particles; the internal structure of the first type of secondary particles (large particles) is a radial structure with a suitable porosity. After mixed lithium sintering, some pores remain on the surface, and there are stable lithium ion transmission channels inside, so that lithium ion transmission is smooth, and good rate performance and cycle stability can be obtained; the internal structure of the second type of secondary particles (small particles) is relatively dense, which can ensure a high level of compaction density to the greatest extent, so that a larger mass of positive electrode material can be contained in a unit volume. Two types of precursors with different physical and chemical properties are selected and mixed to obtain a precursor material with high rate performance, strong cycle stability, high specific capacity and energy density.

[0041] The preparation method of the positive electrode material precursor provided by the present disclosure can be obtained by simply mixing two types of precursors; the process is simple.

[0042] The positive electrode material, battery and electrical equipment provided by the present disclosure have high energy density, high cycle stability, large specific capacity and excellent electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0044] FIG1 is a scanning electron microscope image of the first type of secondary particles obtained in Example 1;

[0045] FIG2 is an argon ion cross-sectional polishing diagram of the first type of secondary particles obtained in Example 1;

[0046] FIG3 is a scanning electron microscope image of the second type of secondary particles obtained in Example 1;

[0047] FIG4 is an argon ion cross-sectional polishing image of the second type of secondary particles obtained in Example 1;

[0048] FIG5 is a scanning electron microscope image of the cathode material precursor obtained in Example 1;

[0049] FIG6 is a scanning electron microscope image of the second type of secondary particles obtained in Example 2;

[0050] FIG7 is a scanning electron microscope image of the first type of secondary particles obtained in Example 3;

[0051] FIG8 is a scanning electron microscope image of the first type of secondary particles obtained in Example 4;

[0052] FIG9 is a scanning electron microscope image of the first type of secondary particles obtained in Comparative Example 1;

[0053] FIG10 is an argon ion cross-sectional polishing image of the first type of secondary particles obtained in Comparative Example 1;

[0054] FIG11 is a scanning electron microscope image of the second type of secondary particles obtained in Comparative Example 1;

[0055] FIG12 is an argon ion cross-sectional polishing diagram of the second type of secondary particles obtained in Comparative Example 1;

[0056] FIG13 is a scanning electron microscope image of the first type of secondary particles obtained in Comparative Example 2;

[0057] FIG14 is an argon ion cross-sectional polishing diagram of the first type of secondary particles obtained in Comparative Example 2. DETAILED DESCRIPTION

[0058] The embodiments of the present disclosure will be described in detail below with reference to the examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0059] The endpoints of the ranges and any values ​​disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0060] The present disclosure provides a positive electrode material precursor, including a first type of secondary particles and a second type of secondary particles, wherein the cross-section of the first type of secondary particles is a radial structure, and the porosity of the cross-section is 2%-7%, and optionally 3%-5%; the cross-section of the second type of secondary particles is a non-radial structure, and the porosity of the cross-section is 5%-12%, and optionally 6%-10%.

[0061] Optionally, the porosity of the first type of secondary particles can be 2%, 3%, 4%, 5%, 6%, 7% or any value between 2% and 7%, and the porosity of the second type of secondary particles can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% or any value between 5% and 12%.

[0062] According to the particle size characteristics, precursors can be divided into large-particle precursors (D50 ≥ 7 μm) and small-particle precursors (D50 < 7 μm). The shortcomings of large-particle precursors include the following: ① Although large-particle precursors can provide more active sites, they usually have a lower specific surface area and fewer grain boundaries, so the ion transport speed will be relatively slow; ② Because large-particle precursors have fewer grain boundaries, they are prone to structural defects and instability, which leads to a decrease in the cycle life and safety of the battery; ③ Large-particle precursors have a higher specific capacity than small-particle precursors, but a relatively lower specific energy density. The main defects of small-particle precursors include: ① Small-particle precursors have a larger specific surface area, so they are more prone to surface oxidation and structural changes, resulting in increased loss of active materials; ② There are more grain boundaries in small-particle precursors, which can easily cause safety issues such as hot spots inside the battery and the formation of metal lithium dendrites; ③ Because the specific capacity of small-particle precursors is relatively low, more frequent charge and discharge operations are required, and the cycle life is reduced accordingly. The main application scenario of ternary large and small particle precursors is the field of power batteries, and the material properties required in the field of power batteries are difficult to be fully provided by single large or small particles.

[0063] The positive electrode material precursor provided by the present invention includes a first type of secondary particles and a second type of secondary particles, and the average particle size of the first type of secondary particles is larger than the average particle size of the second type of secondary particles; in some embodiments, the first type of secondary particles are large particles, D50 can be 10-30μm, the internal structure is a radial structure (radial structure), and has a suitable porosity. After mixed lithium sintering, some pores remain on the surface, and there are stable lithium ion transmission channels inside, so that lithium ion transmission is smooth, and good rate performance and cycle stability can be obtained; the second type of secondary particles are small particles, D50 can be 1-6μm, and the internal structure is relatively dense, which can maximize the high level of compaction density, so that a larger mass of positive electrode material can be contained in a unit volume. By selecting two types of precursors with different physical and chemical properties and mixing them, a precursor material with high rate performance, strong cycle stability, high specific capacity and energy density is obtained.

[0064] It should be noted that the radial structure described in the present disclosure means that, from the perspective of the argon ion cross-sectional polishing diagram, the primary particles are arranged in the direction from the center of the secondary particles toward their surface, and the proportion of radial morphology is relatively large (≥50%). The non-radial structure described in the present disclosure means that, from the perspective of the argon ion cross-sectional polishing diagram, only a part (<50%) of the cross-sectional structure of the secondary particles presents a radial structure, and obviously also includes other arrangements (such as perpendicular to the radial direction). Among them, the proportion of the cross-sectional radial structure is the value obtained by fitting the cross-sectional surface of the secondary particles into a circle, and the area of ​​the cross-sectional radial structure / the area of ​​the entire circle.

[0065] It should be noted that the precursor secondary particles disclosed herein are categorized based on cross-sectional morphology and porosity. In certain embodiments of the present disclosure, particles with radial cross-sectional structures and a porosity of 2%-7% are classified as Class I secondary particles, while particles with non-radial cross-sectional structures and a porosity of 5%-12% are classified as Class II secondary particles.

[0066] In an optional embodiment, the average particle size of the first type of secondary particles is greater than the average particle size of the second type of secondary particles.

[0067] Although the average particle size of the first type of secondary particles in the present disclosure is greater than the average particle size of the second type of secondary particles, in some embodiments, there will be a small amount of secondary particles with smaller particle sizes in the first type of secondary particles, and a small amount of secondary particles with larger particle sizes in the second type of secondary particles, and the particle size ranges of the two may overlap. For a precursor sample after the first type of secondary particles and the second type of secondary particles have been mixed, in order to characterize the size relationship between the average particle sizes of the first type of secondary particles and the second type of secondary particles, more than 10 (for example, 20, 30, 40, 50 or more than 50) secondary particles of different particle sizes can be randomly taken for testing, and their cross-sections can be observed. If the cross-section has a radial structure and a porosity of 2%-7%, it belongs to the first type of secondary particles; if the cross-section has a non-radial structure and a porosity of 5%-12%, it belongs to the second type of secondary particles; according to the classification, the particle size of each type of secondary particles is tested, and then the arithmetic mean is calculated to obtain the average particle size of each type of secondary particles, thereby verifying that the average particle size of the first type of secondary particles is greater than the average particle size of the second type of secondary particles.

[0068] In an optional embodiment, the primary particles of the first type of secondary particles are spindle-shaped.

[0069] In an optional embodiment, the average length of the primary particles of the first type of secondary particles is 200-800 nm.

[0070] In an optional embodiment, the average width of the primary particles of the first type of secondary particles is 80-200 nm.

[0071] In an optional embodiment, the average aspect ratio of the primary particles of the first type of secondary particles is (2-10):1.

[0072] In an optional embodiment, the average length of the primary particles of the first type of secondary particles is 400-650 nm.

[0073] In an optional embodiment, the average width of the primary particles of the first type of secondary particles is 100-150 nm.

[0074] In an optional embodiment, the average aspect ratio of the primary particles of the first type of secondary particles is (3-6):1.

[0075] Optionally, the average length of the primary particles of the first type of secondary particles may be 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm or any value between 200-800 nm.

[0076] Optionally, the average width of the primary particles of the first type of secondary particles can be 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm or any value between 80-200nm.

[0077] Optionally, the average aspect ratio of the primary particles of the first type of secondary particles can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any value between (2-10):1.

[0078] The primary particles of the first type of secondary particles have suitable size and morphology, which is beneficial to shortening the transmission path of lithium ions and improving rate performance.

[0079] In an optional embodiment, the primary particles of the second type of secondary particles are in block shape.

[0080] In an optional embodiment, the average length of the primary particles of the second type of secondary particles is 500-1000 nm.

[0081] In an optional embodiment, the average width of the primary particles of the second type of secondary particles is 50-300 nm.

[0082] In an optional embodiment, the average aspect ratio of the primary particles of the second type of secondary particles is (2-8):1.

[0083] In an optional embodiment, the average length of the primary particles of the second type of secondary particles is 700-1000 nm.

[0084] In an optional embodiment, the average width of the primary particles of the second type of secondary particles is 150-300 nm.

[0085] In an optional embodiment, the average aspect ratio of the primary particles of the second type of secondary particles is (3-5):1.

[0086] Optionally, the average length of the primary particles of the second type of secondary particles may be 500, 600, 700, 800, 900, 1000 or any value between 500-1000 nm.

[0087] Optionally, the average width of the primary particles of the second type of secondary particles can be 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm or any value between 90-300nm.

[0088] Optionally, the average aspect ratio of the primary particles of the second type of secondary particles can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any value between (2-8):1.

[0089] The primary particles of the first type of secondary particles are block-shaped and relatively thick, which is conducive to forming a dense internal structure and improving the overall compaction density.

[0090] The average length and average width of primary particles are measured using Nano Measurer software. The average length and average width of the primary particles on the surface of the secondary particles are measured in a scanning electron microscope image at a magnification of N times (e.g., 5000 times). The longest axis of a single primary particle is considered its length, and the short axis measured perpendicular to the midpoint of the longest axis is considered its average width. Data for at least 10 primary particles are averaged to obtain the average width and average length of the primary particles, and the average aspect ratio (average length / average width) is calculated. The average length, average width, and average aspect ratio of the primary particles disclosed herein are all obtained using this method.

[0091] Porosity measurement / calculation method: Use image analysis software (ImageJ) to directly determine the pore area and cross-sectional area of ​​argon ion polished cross-section images at a magnification of 5000x-30000x. The porosity of each region is calculated using the formula "porosity = pore area per region / cross-sectional area per region × 100%." ​​The porosity can be calculated from several (e.g., five) argon ion polished cross-sectional images and then averaged. All porosities reported in this article were obtained using this method.

[0092] In an optional embodiment, the cathode material precursor satisfies one or more of the following conditions:

[0093] a. The particle size D50 of the cathode material precursor is 7.5-20 μm, optionally 10-20 μm;

[0094] b. The specific surface area of ​​the cathode material precursor is 5-15m 2 / g, optional 8-12m 2 / g;

[0095] c. The tap density TD of the positive electrode material precursor is not less than 2.2 g / cm 3 .

[0096] Optionally, the D50 of the positive electrode material precursor may be 7.5 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or any value between 8 and 20 μm.

[0097] The D50 of the cathode material precursor is relatively large, which can ensure the energy density to a certain extent.

[0098] Optionally, the BET of the cathode material precursor may be 5m 2 / g、6m 2 / g、7m 2 / g、8m 2 / g、9m 2 / g、10m 2 / g、11m 2 / g、12m 2 / g、13m 2 / g、14m 2 / g、15m 2 / g or 5-15m 2 Any value between / g.

[0099] Optionally, the TD of the cathode material precursor may be 2.2 g / cm 3 , 2.3g / cm 3 , 2.4g / cm 3 , 2.5g / cm 3 , 2.6g / cm 3 , 2.7g / cm 3 , 2.8g / cm 3 , 2.9g / cm 3 , 3.0g / cm 3 , 3.1g / cm 3 、3.2g / cm 3 , 3.3g / cm 3 or not less than 2.2g / cm 3 Any value of .

[0100] A suitable specific surface area and / or tap density is beneficial to taking into account the capacity, cycle performance and safety performance of the material.

[0101] In an optional embodiment, the mass ratio of the first type of secondary particles to the second type of secondary particles is (1-6):1, optionally (2-6):1.

[0102] Optionally, the mass ratio of the first type of secondary particles to the second type of secondary particles can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1 or any value between (1.5-6):1.

[0103] An appropriate mass ratio of large and small particles can not only ensure that large particles contribute to providing energy density and cycle stability, but also ensure that small particles fill the pores between large particles to the greatest extent, thereby improving specific capacity.

[0104] In an optional embodiment, the positive electrode material precursor is a hydroxide containing a transition metal.

[0105] In an optional embodiment, the transition metal-containing hydroxide contains Ni, and optionally contains Co and / or Mn.

[0106] In an optional embodiment, the chemical formula of the positive electrode material precursor is Ni x Co y Mn z M a (OH)2, wherein 0.50≤x<1.0, 0≤y≤0.50, 0≤z≤0.50, x+y+z=1, M includes one or more of Al, Ti, Mg, Zr, W and Zn, and 0≤a≤0.20.

[0107] Alternatively, x may be 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, 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, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95 0.95, 0.96, 0.97, 0.98, 0.99 or any value greater than or equal to 0.50 and less than 1.0; y can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 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, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50 or any value between 0 and 0.50; z can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 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, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50 or any value between 0 and 0.50; a can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 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 or any value between 0 and 0.20.

[0108] The present disclosure also provides a method for preparing the positive electrode material precursor, comprising:

[0109] obtaining the first type of secondary particles and the second type of secondary particles respectively;

[0110] The first type of secondary particles and the second type of secondary particles are mixed to obtain the positive electrode material precursor.

[0111] The present disclosure also provides a positive electrode material, the raw materials of which include the positive electrode material precursor.

[0112] The present disclosure also provides a battery comprising the positive electrode material.

[0113] The present disclosure also provides an electrical device, comprising the battery.

[0114] The embodiments of the present disclosure will be described in detail below with reference to specific examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0115] Example 1

[0116] This embodiment provides a positive electrode material precursor, the chemical formula of which is Ni 0.92 Co 0.04 Mn 0.04 (OH)2, the specific preparation method is as follows:

[0117] 1. The chemical formula is Ni 0.92 Co 0.04 Mn 0.04 The preparation method of the first type of secondary particles of (OH)2: according to the molar ratio of nickel, cobalt and manganese elements, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water, and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116g / L, and then the mixed solution A and a 32wt% ammonia water complexing agent and a 21wt% sodium hydroxide solution precipitant are added to a reactor, and under nitrogen protective gas, the flow rate of the sodium hydroxide solution is adjusted to 2.92L / h and the flow rate of the ammonia water is adjusted to 0.18L / h, so that the pH in the reactor is maintained at 11.1-11.5 and the temperature is between 55-65°C. After stirring the reaction for 8 hours, the mixture is aged for 10 hours, and the first type of secondary particles are obtained after solid-liquid separation, washing and drying.

[0118] Test results: The scanning electron microscope image of the obtained first type of secondary particles is shown in Figure 1, and the argon ion cross-sectional polishing image is shown in Figure 2. The D50 is 13.9 μm.

[0119] 2. The chemical formula is Ni 0.92Co 0.04 Mn 0.04 The preparation method of the second type of secondary particles of (OH)2: according to the molar ratio of nickel, cobalt and manganese elements, soluble nickel salt, cobalt salt and manganese salt are mixed with water, and stirred until completely dissolved to obtain a mixed solution D with a total metal ion concentration of 116g / L, and then the mixed solution D and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to a reactor. Under nitrogen protective gas, the flow rate of the sodium hydroxide solution is adjusted to 1.83L / h and the flow rate of the ammonia water is adjusted to 0.35L / h, so that the pH in the reactor is maintained between 10.9 and 11.1, and the temperature is between 55-65°C. After stirring and reacting for 28 hours, the second type of secondary particles are obtained after solid-liquid separation, washing and drying.

[0120] Test results: The scanning electron microscope image of the obtained second type of secondary particles is shown in Figure 3, and the argon ion cross-sectional polishing image is shown in Figure 4. The D50 is 3.8μm.

[0121] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain a target positive electrode material precursor.

[0122] FIG5 is a scanning electron microscope image of the target cathode material precursor.

[0123] Example 2

[0124] This embodiment provides a positive electrode material precursor, the chemical formula of which is Ni 0.92 Co 0.04 Mn 0.04 (OH)2, the specific preparation method is as follows:

[0125] 1. The first type of secondary particles and their preparation method are the same as those in Example 1;

[0126] 2. The second type of secondary particles Ni 0.92 Co 0.04 Mn 0.04 Preparation method of (OH)2: Different from Example 1, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water according to the molar ratio of nickel, cobalt and manganese elements = 92:4:4, and stirred until completely dissolved to obtain a mixed solution D with a total metal ion concentration of 116 g / L, and then the mixed solution D and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to a reactor, and under a double-tube nitrogen protective gas, the flow rate of the sodium hydroxide solution is adjusted to 1.44L / h and the flow rate of the ammonia water is adjusted to 0.18L / h, so that the pH in the reactor is maintained at 10.1-10.5 and the temperature is between 55-65°C. After stirring and reacting for 20 hours, the second type of secondary particulate nickel-cobalt-manganese precursor is obtained after solid-liquid separation, washing and drying.

[0127] Test results: The scanning electron microscope image of the obtained second type of secondary particles is shown in Figure 6, and D50 is 3.5 μm.

[0128] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain a target positive electrode material precursor.

[0129] Example 3

[0130] This embodiment provides a positive electrode material precursor, and the specific preparation method is as follows:

[0131] 1. The first type of secondary particle precursor and its preparation method: Different from Example 1, according to the molar ratio of nickel, cobalt and manganese elements = 80:14:6, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116 g / L, and then the mixed solution A and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to the reactor. Under nitrogen protective gas, the flow rate of sodium hydroxide solution is adjusted to 1.74L / h and the flow rate of ammonia is adjusted to 0.11L / h, so that the pH in the reactor is maintained at 10.6-11.0 and the temperature is between 60-70°C. The reaction is stirred continuously, and the reaction is controlled to be stable before the material is added. After solid-liquid separation, washing and drying, the nickel-cobalt-manganese precursor Ni is obtained. 0.80 Co 0.14 Mn 0.06 (OH)2.

[0132] Test results: The scanning electron microscope image of the obtained first type of secondary particles is shown in Figure 7, and D50 is 9.5 μm.

[0133] 2. The second type of secondary particles and their preparation method are the same as those in Example 1.

[0134] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.836 Co 0.110 Mn 0.054 (OH)2, the estimated process is, Ni = (80*7 + 92*3) / 1000 = 0.836, Co = (14*7 + 4*3) / 1000 = 0.11, Mn = (6*7 + 4*3) / 1000 = 0.054, so the chemical formula after embodiment 3 is estimated to be Ni 0.836 Co 0.110 Mn 0.054 (OH) 2. The chemical formulas of the mixed precursors obtained in all examples and comparative examples were estimated by this method.

[0135] Example 4

[0136] This embodiment provides a positive electrode material precursor, and the specific preparation method is as follows:

[0137] 1. The first type of secondary particles and preparation method thereof: Different from Example 1, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water according to the molar ratio of nickel, cobalt and manganese elements = 96:3:1, and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116 g / L, and then the mixed solution A is added to a reactor with a concentration of 32wt% ammonia complexing agent and a concentration of 21wt% sodium hydroxide solution precipitant. Under nitrogen protective gas, the flow rate of sodium hydroxide solution is adjusted to 2.2L / h and the flow rate of ammonia water is adjusted to 0.55L / h, so that the pH in the reactor is maintained at 12.1-12.3 and the temperature is between 55-65°C. After stirring and reacting for 40 hours, solid-liquid separation, washing, and drying are performed to obtain the first type of secondary particles Ni 0.96 Co 0.03 Mn 0.01 (OH)2.

[0138] Test results: The scanning electron microscope image of the obtained first type of secondary particles is shown in Figure 8, and D50 is 12.4 μm.

[0139] 2. The second type of secondary particles and their preparation method are the same as those in Example 1.

[0140] The first type of secondary particles and the second type of secondary particles obtained above were mixed uniformly in a mass ratio of 1:1 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.94 Co 0.035 Mn 0.025 (OH)2.

[0141] Comparative Example 1

[0142] This comparative example provides a positive electrode material precursor, and the specific preparation method is as follows:

[0143] 1. The first type of secondary particles and preparation method thereof: Different from Example 1, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water according to the molar ratio of nickel, cobalt and manganese elements = 88:10:2, and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116 g / L, and then the mixed solution A and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to a reactor. Under nitrogen protective gas, the flow rate of the sodium hydroxide solution is adjusted to 1.3 L / h and the flow rate of the ammonia solution is adjusted to 0.5 L / h, so that the pH in the reactor is maintained at 11.8-12.1 and the temperature is between 55-65°C. After stirring and reacting for 20 hours, the first type of secondary particles Ni are obtained after solid-liquid separation, washing and drying.0.88 Co 0.10 Mn 0.02 (OH)2.

[0144] Test results: The surface scanning electron microscope image of the obtained first type of secondary particles is shown in Figure 9, and the argon ion cross-sectional polishing image is shown in Figure 10. The D50 is 14.3 μm.

[0145] 2. The second type of secondary particles and their preparation method: Different from Example 1, according to the molar ratio of nickel, cobalt and manganese elements = 67.5:5:27.5, an intermittent preparation method is adopted, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water, and stirred until completely dissolved to obtain a mixed solution D with a total metal ion concentration of 116 g / L, and then the mixed solution D is added to a reactor with a concentration of 32wt% ammonia complexing agent and a concentration of 21wt% sodium hydroxide solution precipitant. Under nitrogen protective gas, the flow rate of sodium hydroxide solution is adjusted to 1.55 / h and the flow rate of ammonia water is adjusted to 0.15L / h, so that the pH in the reactor is maintained at 11.2-11.4 and the temperature is between 55-65°C. After stirring and reacting for 20 hours, solid-liquid separation, washing, and drying are performed to obtain nickel-cobalt-manganese precursor Ni 0.675 Co 0.05 Mn 0.275 (OH)2.

[0146] Test results: The surface scanning electron microscope image of the obtained second type of secondary particles is shown in Figure 11, and the argon ion cross-sectional polishing image is shown in Figure 12. The D50 is 3.6 μm.

[0147] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.82 Co 0.085 Mn 0.095 (OH)2.

[0148] Comparative Example 2

[0149] This comparative example provides a positive electrode material precursor, and the specific preparation method is as follows:

[0150] 1. The first type of secondary particles and preparation method thereof: Different from Example 1, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water according to the molar ratio of nickel, cobalt and manganese elements = 87.5:7:5.5, and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116 g / L, and then the mixed solution A and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to a reactor. Under nitrogen protective gas, the flow rate of the sodium hydroxide solution is adjusted to 1.62 L / h and the flow rate of the ammonia solution is adjusted to 0.22 L / h, so that the pH in the reactor is maintained at 10.3-10.5 and the temperature is between 60-70°C. The reaction is stirred continuously, and the materials are added when the reaction is stable. After solid-liquid separation, washing and drying, the first type of secondary particles Ni are obtained. 0.875 Co 0.07 Mn 0.055 (OH)2.

[0151] Test results: The surface scanning electron microscope image of the obtained first type of secondary particles is shown in Figure 13, and the argon ion cross-sectional polishing image is shown in Figure 14. The D50 is 11.5 μm.

[0152] 2. The second type of secondary particles and their preparation method are the same as those in Comparative Example 1.

[0153] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.815 Co 0.064 Mn 0.121 (OH)2.

[0154] Comparative Example 3

[0155] This comparative example provides a positive electrode material precursor, and the specific preparation method is as follows:

[0156] The first type of secondary particles are the same as those in Example 1, and the second type of secondary particles are the same as those in Comparative Example 2.

[0157] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.847 Co 0.043 Mn 0.110 (OH)2.

[0158] Comparative Example 4

[0159] This comparative example provides a positive electrode material precursor, and the specific preparation method is as follows:

[0160] The first type of secondary particles are the same as those in Comparative Example 2, and the second type of secondary particles are the same as those in Example 1.

[0161] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.888 Co 0.062 Mn 0.05 (OH)2.

[0162] Comparative Example 5

[0163] The first type of secondary particles are the same as in Example 1, and the second type of secondary particles are prepared as follows:

[0164] The difference from Example 1 is that, according to the molar ratio of nickel, cobalt and manganese elements = 92:4:4, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water and stirred until completely dissolved to obtain a mixed solution D with a total metal ion concentration of 116 g / L, and then the mixed solution D and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to the reactor, and under the double-tube nitrogen protective gas, the sodium hydroxide solution flow rate is adjusted to 1.52 L / h and the ammonia flow rate is 0.12 L / h, so that the pH in the reactor is maintained at 10.5-11.0 and the temperature is between 55-65°C. After stirring and reacting for 35 hours, the second type of secondary particle nickel-cobalt-manganese precursor Ni is obtained after solid-liquid separation, washing and drying. 0.92 Co 0.04 Mn 0.04 (OH)2, particle size D50 is 3.3μm.

[0165] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.92 Co 0.04 Mn 0.04 (OH)2.

[0166] Comparative Example 6

[0167] The second type of secondary particles are the same as in Example 1. The preparation method of the first type of secondary particles is as follows:

[0168] The difference from Example 1 is that, according to the molar ratio of nickel, cobalt and manganese elements = 92:4:4, soluble nickel sulfate, cobalt sulfate and manganese sulfate are mixed with water and stirred until completely dissolved to obtain a mixed solution A with a total metal ion concentration of 116 g / L, and then the mixed solution A and a 32wt% ammonia complexing agent and a 21wt% sodium hydroxide solution precipitant are added to the reactor, and under the double-tube nitrogen protective gas, the sodium hydroxide solution flow rate is adjusted to 2.76 L / h and the ammonia flow rate is 0.38 L / h, so that the pH in the reactor is maintained at 10.8-11.3 and the temperature is between 55-65°C. After stirring and reacting for 44 hours, the second type of secondary particle nickel-cobalt-manganese precursor Ni is obtained after solid-liquid separation, washing and drying. 0.92 Co 0.04 Mn 0.04 (OH)2, particle size D50 is 14.1μm.

[0169] The first type of secondary particles and the second type of secondary particles obtained above were mixed evenly in a mass ratio of 7:3 to obtain the target cathode material precursor. It was estimated that the chemical formula of the target cathode material precursor was Ni 0.92 Co 0.04 Mn 0.04 (OH)2.

[0170] The test results of various embodiments and comparative examples are shown in Table 1 and Table 2.

[0171] Table 1 Electrochemical properties of cathode materials made from precursors of various embodiments and comparative examples

[0172] Table 2 Physicochemical parameters of precursors of Examples 1-4 and Comparative Examples 1-4

[0173] It can be seen from Examples 1 to 4 that the positive electrode active material synthesized by the large and small mixed precursors with a specific proportion of the special structure disclosed in the present invention has an initial discharge capacity of more than 225mAh / g at 1C (200mA / g) in the voltage range of 3.0 to 4.3V, and a capacity retention rate of more than 85% after 100 cycles at 8C, and a rate performance of more than 87.2% at 8C / 1C. It has high discharge capacity, rate performance and capacity retention, and it can also be seen that the positive electrode material has good safety performance. The electrochemical test of the positive electrode material made of the first type of secondary particles alone and the second type of secondary particles alone in Example 1 shows that the electrical performance is not as good as the positive electrode material of the embodiment after mixing. Comparing the embodiment with Comparative Examples 1-4, it can be seen that the morphology and structure of the first type of secondary particles and the second type of secondary particles (the arrangement and porosity of the primary particles) have an impact on the overall effect. In the embodiment, the first type of secondary particles and the second type of precursors with suitable morphology and structure are cleverly selected to make the two cooperate better, and the overall electrochemical performance is more excellent.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 disclosure. Industrial Applicability

[0175] The present disclosure provides a cathode material precursor and a preparation method thereof, a cathode material, a battery and electrical equipment, which are suitable for industrial production in the battery field.

Claims

1. A cathode material precursor, characterized in that: The invention comprises first-type secondary particles and second-type secondary particles. The cross section of the first-type secondary particles is radial and has a porosity of 2%-7%. The cross section of the second-type secondary particles is non-radial and has a porosity of 5%-12%.

2. The cathode material precursor according to claim 1, characterized in that The average particle size of the first type of secondary particles is greater than the average particle size of the second type of secondary particles; Optionally, the primary particles of the first type of secondary particles are spindle-shaped; Optionally, the average length of the primary particles of the first type of secondary particles is 200-800 nm, optionally 400-650 nm; Optionally, the average width of the primary particles of the first type of secondary particles is 80-200 nm, optionally 100-150 nm; Optionally, the average aspect ratio of the primary particles of the first type of secondary particles is (2-10):1, optionally (3-6):

1.

3. The cathode material precursor according to claim 1, characterized in that The primary particles of the second type of secondary particles are in block shape; Optionally, the average length of the primary particles of the second type of secondary particles is 500-1000 nm, optionally 700-1000 nm; Optionally, the average width of the primary particles of the second type of secondary particles is 50-300 nm, optionally 150-300 nm; Optionally, the average aspect ratio of the primary particles of the second type of secondary particles is (2-8):1, optionally (3-5):

1.

4. The cathode material precursor according to claim 1, characterized in that One or more of the following conditions are met: a. The particle size D50 of the cathode material precursor is 7.5-20 μm, optionally 10-20 μm; b. The specific surface area of the cathode material precursor is 5-15m 2 / g, optional 8-12m 2 / g; c. The tap density TD of the positive electrode material precursor is not less than 2.2 g / cm 3 .

5. The cathode material precursor according to claim 1, characterized in that The mass ratio of the first type of secondary particles to the second type of secondary particles is (1-6):1, and can be optionally (2-6):

1.

6. The cathode material precursor according to any one of claims 1 to 5, characterized in that: The positive electrode material precursor is a hydroxide containing a transition metal; Optionally, the transition metal-containing hydroxide contains Ni, and optionally further contains Co and / or Mn; Optionally, the chemical formula of the positive electrode material precursor is Ni x Co y Mn z M a (OH)2, wherein 0.50≤x<1.0, 0≤y≤0.50, 0≤z≤0.50, x+y+z=1, M includes one or more of Al, Ti, Mg, Zr, W and Zn, and 0≤a≤0.

20.

7. A method for preparing a cathode material precursor according to any one of claims 1 to 6, characterized in that: include: obtaining the first type of secondary particles and the second type of secondary particles respectively; The first type of secondary particles and the second type of secondary particles are mixed to obtain the positive electrode material precursor.

8. A positive electrode material, characterized in that The raw materials include the positive electrode material precursor according to any one of claims 1 to 6.

9. A battery, characterized in that: Comprising the positive electrode material according to claim 8.

10. An electrical equipment, characterized in that: A battery comprising the battery of claim 9.

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