An ultrahigh-nickel ternary precursor, a preparation method thereof, a positive electrode material, a lithium ion battery, and an electric device

Abstract

The application provides an ultrahigh-nickel ternary precursor, a preparation method of the ultrahigh-nickel ternary precursor, a positive electrode material, a lithium ion battery and an electric device, and relates to the field of lithium ion batteries. x Co y Mn 1‑x‑y (OH)2, 0.90≤x≤0.96, 0 The average length and the average width of the primary particles satisfy: average length: average width = 2-4: 1. The secondary particle surface of the ultrahigh-nickel ternary precursor is free of cracks, and the primary particles of the ultrahigh-nickel ternary precursor have the feature of preferential growth along the [001] direction in crystallography, so that the precursor has optimal crystallographic orientation, the ion migration path is short after sintering to form the positive electrode material, the stability is good, and the comprehensive electrical performance is excellent.

Description

Technical Field

[0001] The present application relates to the field of lithium-ion batteries, and in particular to an ultra-high nickel ternary precursor and a preparation method thereof, a positive electrode material, a lithium-ion battery and electrical equipment. Background Art

[0002] Ternary precursor materials hold a crucial position in the lithium-ion battery field and are key raw materials for the preparation of ternary cathode materials. The new energy vehicle industry is currently experiencing rapid growth, and ternary precursor materials are widely used to power electric vehicles, helping to achieve long driving range and high performance. With the further development of the lithium-ion battery industry, demand for high-performance ternary precursor materials is on the rise. Emerging markets, such as the low-altitude economy, are demanding even higher energy density ternary battery materials to enhance battery energy density, while also providing excellent cycle stability and safety.

[0003] Existing ultra-high nickel ternary precursor materials have certain shortcomings. In terms of performance, the energy density of some materials has limited improvement, making it difficult to meet the growing demand for high capacity; the cycle stability is poor, and after multiple charge and discharge cycles, the battery capacity decays significantly, affecting the service life. In terms of preparation technology, some methods make it difficult to accurately control the particle size and morphology of the precursor, resulting in poor product consistency and affecting the overall performance of the battery. In addition, the preparation process may be more complicated and costly, which limits large-scale application; and the existing technology has not optimized the primary particle size ratio and primary particle orientation of the ultra-high nickel ternary precursor, which can easily lead to problems such as long ion migration path and insufficient structural stability of the positive electrode material formed by its sintering. Summary of the Invention

[0004] The purpose of this application is to provide an ultra-high nickel ternary precursor and its preparation method, positive electrode material, lithium-ion battery and electrical equipment to solve the above problems.

[0005] To achieve the above objectives, the present application provides a first aspect of an ultra-high nickel ternary precursor, the chemical formula of which is Ni x Co y Mn 1-x-y (OH)2, 0.90≤x≤0.96, 0<y≤0.03;

[0006] The average length and average width of the primary particles satisfy:

[0007] Average length: average width = 2-4:1.

[0008] Optionally, the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0009] (1) The average length of the primary particles is 0.5 μm-1.0 μm, and the average width of the primary particles is 0.2 μm-0.4 μm;

[0010] (2) The D50 of the ultra-high nickel ternary precursor is 10 μm-20 μm.

[0011] The second aspect of the present application provides a method for preparing the ultra-high nickel ternary precursor, comprising:

[0012] Under a protective atmosphere, a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution, and ammonia water are introduced into a base liquid containing a sodium hydroxide solution and ammonia water to perform a first coprecipitation reaction to obtain seed crystals;

[0013] Mixing the seed crystals, water, and aqueous ammonia to obtain a mixture, and introducing a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution, and aqueous ammonia into the mixture to perform a second coprecipitation reaction to obtain an ultra-high nickel ternary precursor;

[0014] The second coprecipitation reaction includes a first stage and a second stage performed sequentially, and the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is greater than the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage.

[0015] Optionally, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0016] (1) The flow rate ratio of the nickel-cobalt-manganese mixed metal salt solution in the first stage to the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 2-4:1;

[0017] (2) the ratio of the alkalinity in the first stage to the alkalinity in the second stage is 1:1.5-2;

[0018] (3) The D50 of the particles prepared in the first stage is 0.5 to 0.7 times the target D50 of the ultra-high nickel ternary precursor.

[0019] Optionally, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0020] (1) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is 0.003%V 反应釜 / min-0.008%V 反应釜 / min;

[0021] (2) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 0.001%V 反应釜 / min-0.002%V 反应釜 / min;

[0022] (3) The growth rate of the particles in the first stage is 0.4 μm / h-0.6 μm / h;

[0023] (4) The duration of the first stage is 5h-15h;

[0024] (5) The alkalinity in the first stage is 10 g / L-12 g / L;

[0025] (6) The growth rate of the particles in the second stage is 0.1 μm / h-0.4 μm / h;

[0026] (7) The duration of the second stage is 20h-40h;

[0027] (8) The alkalinity in the second stage is 15 g / L-20 g / L.

[0028] Optionally, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0029] (1) the total metal molar concentration in the nickel-cobalt-manganese mixed metal salt solution is 1.0 mol / L-2.5 mol / L;

[0030] (2) the molar concentration of the sodium hydroxide solution is 5 mol / L-10 mol / L;

[0031] (3) the molar concentration of ammonium ions in the ammonia water is 6 mol / L-12 mol / L;

[0032] (4) The pH value of the base solution is 12-13;

[0033] (5) The alkalinity of the base solution is 2 g / L-10 g / L;

[0034] (6) The pH value of the first coprecipitation reaction is 11-12;

[0035] (7) The temperature of the first coprecipitation reaction is 60° C.-80° C.;

[0036] (8) The stirring speed of the first coprecipitation reaction is 600 rpm-700 rpm;

[0037] (9) The D50 of the seed crystal is 0.2 to 0.4 times the target D50 of the ultra-high nickel ternary precursor;

[0038] (10) The pH value of the second coprecipitation reaction is 10-11;

[0039] (11) The temperature of the second coprecipitation reaction is 40°C-60°C;

[0040] (12) The stirring speed of the second coprecipitation reaction is 400 rpm-500 rpm.

[0041] Optionally, after the second coprecipitation reaction, aging, washing, and drying are further performed, and at least one of the following conditions is met:

[0042] (1) the solid content of the material after the second coprecipitation reaction is 400 g / L-600 g / L;

[0043] (2) using alkali for aging, wherein the mass concentration of the alkali is 10%-20%;

[0044] (3) The aging temperature is 60°C-80°C and the time is 30min-70min;

[0045] (4) the end point pH value of the washing is 8.0-9.0;

[0046] (5) The drying temperature is 100°C-140°C.

[0047] The ultra-high nickel ternary precursor provided in the first aspect of the present application can be prepared by the preparation method of the ultra-high nickel ternary precursor provided in the second aspect of the present application.

[0048] The third aspect of the present application provides a positive electrode material, including the ultra-high nickel ternary precursor or prepared by the ultra-high nickel ternary precursor preparation method.

[0049] A fourth aspect of the present application provides a lithium-ion battery comprising the aforementioned positive electrode material.

[0050] A fifth aspect of the present application provides an electrical device comprising the lithium-ion battery.

[0051] Compared with the prior art, the advantages of this application include:

[0052] The ultra-high nickel ternary precursor provided in this application has no cracks on the surface of the secondary particles, and its primary particles have the characteristic of preferential growth along the

[001] direction in crystallography, so that the precursor has the optimal crystallographic orientation. After sintering to form the positive electrode material, the ion migration path is short, the stability is good, and the overall electrical performance is excellent.

[0053] The preparation method of the ultra-high nickel ternary precursor provided in the present application uses an intermittent process and a seed template method to adjust the flow rate of the nickel-cobalt-manganese mixed metal salt solution in stages in the second co-precipitation reaction to regulate the D50 growth rate; at a high growth rate, the primary particles are mainly deposited and grown along the length direction, and at a low growth rate, the primary particles are mainly deposited and grown along the width (thickness) direction, thereby achieving control of the dimensional characteristics of the ultra-high nickel ternary precursor; the preparation method of the ultra-high nickel ternary precursor does not introduce complex technologies such as element doping, does not require equipment modification, and has low production costs; the production process is stable, has good operability, and is easy to mass produce.

[0054] The positive electrode material, lithium-ion battery and electrical equipment provided in this application have excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0056] Figure 1 This is a width-marked SEM image of primary particles of the ultra-high nickel ternary precursor provided in Example 1;

[0057] Figure 2 Length-marked SEM image of primary particles of the ultra-high nickel ternary precursor provided in Example 1;

[0058] Figure 3 This is a width-marked SEM image of the primary particles of the ultra-high nickel ternary precursor provided in Example 2;

[0059] Figure 4 Length-marked SEM image of primary particles of the ultra-high nickel ternary precursor provided in Example 2;

[0060] Figure 5 A width-marked SEM image of primary particles of the ultra-high nickel ternary precursor provided in Comparative Example 1;

[0061] Figure 6 Length-marked SEM image of primary particles of the ultra-high nickel ternary precursor provided in Comparative Example 1. DETAILED DESCRIPTION

[0062] First, the solution provided in this application is explained in more detail as follows:

[0063] The first aspect of the present application provides an ultra-high nickel ternary precursor, the chemical formula of which is Ni x Co y Mn 1-x-y(OH)2, 0.90≤x≤0.96, 0<y≤0.03;

[0064] Optionally, in the chemical formula of the ultra-high nickel ternary precursor, x may be 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, or any value between 0.90 and 0.96, and y may be 0.001, 0.01, 0.02, 0.03, or any value greater than 0 and less than or equal to 0.03;

[0065] The average length and average width of the primary particles satisfy:

[0066] Average length: average width = 2-4:1.

[0067] Optionally, the ratio of the average length of the primary particles to the average width of the primary particles may be 2:1, 2.4:1, 2.5:1, 2.6:1, 2.9:1, 3:1, 3.5:1, 3.7:1, 4:1, or any value between 2 and 4:1, preferably 2.4-3.7:1.

[0068] It should be noted that when the primary particles are too slender and the average length: average width is greater than 4:1, it is easy to cause particle breakage during the cycle, aggravated interface side reactions, and poor cycle performance; when the average length: average width of the primary particles is less than 2:1, the primary particles are too thick and short, with fewer surface active sites, the lithium ion diffusion path is blocked, and the capacity is hindered.

[0069] It should also be noted that the length of a primary particle refers to the extended dimension along the main growth direction of the primary particle, and the width (thickness) of a primary particle refers to the dimension perpendicular to the growth direction of the particle; and the average length and average width of a primary particle refer to randomly selecting ≥30 primary particles with clear outlines, measuring their lengths and widths respectively, and calculating their average length and average width respectively.

[0070] In some embodiments, the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0071] (1) The average length of the primary particles is 0.5 μm-1.0 μm, and the average width of the primary particles is 0.2 μm-0.4 μm;

[0072] Optionally, the average length of the primary particles may be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm or any value between 0.5 μm and 1.0 μm, and the average width of the primary particles may be 0.2 μm, 0.25 μm, 0.3 μm, 0.4 μm or any value between 0.2 μm and 0.4 μm; preferably, 0.2 μm to 0.3 μm;

[0073] (2) The D50 of the ultra-high nickel ternary precursor is 10 μm-20 μm.

[0074] Optionally, the D50 of the ultra-high nickel ternary precursor may be 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 10 μm and 20 μm, preferably between 13 μm and 16 μm.

[0075] The second aspect of the present application provides a method for preparing the ultra-high nickel ternary precursor, comprising:

[0076] Under a protective atmosphere, a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution, and ammonia water are introduced into a base liquid containing a sodium hydroxide solution and ammonia water to perform a first coprecipitation reaction to obtain seed crystals;

[0077] Mixing the seed crystals, water, and aqueous ammonia to obtain a mixture, and introducing a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution, and aqueous ammonia into the mixture to perform a second coprecipitation reaction to obtain an ultra-high nickel ternary precursor;

[0078] The second coprecipitation reaction includes a first stage and a second stage performed sequentially, and the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is greater than the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage.

[0079] It should be noted that high salt flow conditions will increase local supersaturation, promote rapid nucleation and axial growth in a short period of time, and form slender particles; while low flow conditions will reduce the feed rate and be conducive to the radial thickening of the particles.

[0080] In some embodiments, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0081] (1) The flow rate ratio of the nickel-cobalt-manganese mixed metal salt solution in the first stage to the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 2-4:1;

[0082] Optionally, the flow rate ratio of the nickel-cobalt-manganese mixed metal salt solution in the first stage to the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage can be 2:1, 3:1, 4:1 or any value between 2 and 4:1;

[0083] (2) the ratio of the alkalinity in the first stage to the alkalinity in the second stage is 1:1.5-2;

[0084] Optionally, the ratio of the alkalinity in the first stage to the alkalinity in the second stage may be 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, or any value between 1:1.5 and 2;

[0085] It should be noted that when the ratio of the alkalinity in the first stage to the alkalinity in the second stage is greater than 1:1.5, there is no difference in the complexation effect, but the growth orientation of the primary particles in different stages cannot be adjusted; when the ratio of the alkalinity in the first stage to the alkalinity in the second stage is less than 1:2, the alkalinity ratio is high, the difference in the complexation effect is too large, and the primary particle size cannot be reasonably adjusted;

[0086] (3) The D50 of the particles prepared in the first stage is 0.5 to 0.7 times the target D50 of the ultra-high nickel ternary precursor.

[0087] Optionally, the D50 of the particles prepared in the first stage is 0.5 times, 0.6 times, 0.7 times or any value between 0.5 times and 0.7 times the target D50 of the ultra-high nickel ternary precursor.

[0088] It should be noted that when the D50 of the particles prepared in the first stage is 0.5 times to 0.7 times the target D50 of the ultra-high nickel ternary precursor, it can ensure that there is sufficient time and space for the axial elongation growth and radial width growth of the primary particles within the set particle size range. If the parameters are not within the set range, customized adjustment of the primary particle size cannot be achieved, and the average length of the primary particles: the average width of the primary particles = 2-4:1 cannot be achieved.

[0089] In some embodiments, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0090] (1) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is 0.003%V 反应釜 / min-0.008%V 反应釜 / min;

[0091] Optionally, the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage can be 0.003%V 反应釜 / min、0.004%V 反应釜 / min、0.005%V 反应釜 / min、0.006%V 反应釜 / min、0.007%V 反应釜 / min、0.008%V 反应釜 / min or 0.003%V 反应釜 / min-0.008%V 反应釜 Any value between / min;

[0092] (2) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 0.001%V 反应釜 / min-0.002%V 反应釜 / min;

[0093] Optionally, the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage can be 0.001%V 反应釜 / min、0.0015%V 反应釜 / min、0.002%V 反应釜 / min or 0.001%V 反应釜 / min-0.002%V 反应釜 Any value between / min;

[0094] (3) The growth rate of the particles in the first stage is 0.4 μm / h-0.6 μm / h;

[0095] Optionally, the growth rate of the particles in the first stage may be 0.4µm / h, 0.5µm / h, 0.6µm / h, or any value between 0.4µm / h and 0.6µm / h;

[0096] It should be noted that high salinity solution flow and high growth rate conditions will increase local supersaturation, promote rapid nucleation and axial growth in a short period of time, and form slender particles; while low salinity solution flow and low growth rate conditions will reduce local supersaturation and facilitate radial thickening (widening) of particles.

[0097] (4) The duration of the first stage is 5h-15h;

[0098] Optionally, the duration of the first stage can be 5h, 10h, 15h, or any value between 5h and 15h;

[0099] (5) The alkalinity in the first stage is 10 g / L-12 g / L;

[0100] Optionally, the alkalinity in the first stage may be 10 g / L, 11 g / L, 12 g / L, or any value between 10 g / L and 12 g / L;

[0101] (6) The growth rate of the particles in the second stage is 0.1 μm / h-0.4 μm / h;

[0102] Optionally, the growth rate of the particles in the second stage may be 0.1µm / h, 0.2µm / h, 0.3µm / h, 0.4µm / h, or any value between 0.1µm / h and 0.4µm / h;

[0103] (7) The duration of the second stage is 20h-40h;

[0104] Optionally, the duration of the second stage can be 20h, 25h, 30h, 35h, 40h or any value between 20h and 40h;

[0105] (8) The alkalinity in the second stage is 15 g / L-20 g / L.

[0106] Optionally, the alkalinity in the second stage can be 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, 20 g / L or any value between 15 g / L and 20 g / L.

[0107] In some embodiments, the method for preparing the ultra-high nickel ternary precursor satisfies at least one of the following conditions:

[0108] (1) the total metal molar concentration in the nickel-cobalt-manganese mixed metal salt solution is 1.0 mol / L-2.5 mol / L;

[0109] Optionally, the total metal molar concentration in the nickel-cobalt-manganese mixed metal salt solution may be 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, or any value between 1.0 mol / L and 2.5 mol / L;

[0110] (2) the molar concentration of the sodium hydroxide solution is 5 mol / L-10 mol / L;

[0111] Optionally, the molar concentration of the sodium hydroxide solution can be 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L or any value between 5 mol / L and 10 mol / L;

[0112] (3) the molar concentration of ammonium ions in the ammonia water is 6 mol / L-12 mol / L;

[0113] Optionally, the molar concentration of ammonium ions in the ammonia water may be 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L or any value between 6 mol / L and 12 mol / L;

[0114] (4) The pH value of the base solution is 12-13;

[0115] Optionally, the pH value of the base solution may be 12, 12.5, 13, or any value between 12 and 13;

[0116] (5) The alkalinity of the base solution is 2 g / L-10 g / L;

[0117] Optionally, the alkalinity of the base solution may be 2 g / L, 4 g / L, 6 g / L, 8 g / L, 10 g / L, or any value between 2 g / L and 10 g / L;

[0118] (6) The pH value of the first coprecipitation reaction is 11-12;

[0119] Optionally, the pH value of the first coprecipitation reaction can be 11, 11.5, 12, or any value between 11 and 12;

[0120] (7) The temperature of the first coprecipitation reaction is 60° C.-80° C.;

[0121] Optionally, the temperature of the first coprecipitation reaction can be 60°C, 70°C, 80°C or any value between 60°C and 80°C;

[0122] (8) The stirring speed of the first coprecipitation reaction is 600 rpm-700 rpm;

[0123] Optionally, the stirring speed of the first coprecipitation reaction can be 600 rpm, 650 rpm, 700 rpm, or any value between 600 rpm and 700 rpm;

[0124] (9) The D50 of the seed crystal is 0.2 to 0.4 times the target D50 of the ultra-high nickel ternary precursor;

[0125] Optionally, the D50 of the seed crystal is 0.2 times, 0.3 times, 0.4 times, or any value between 0.2 times and 0.4 times the target D50 of the ultra-high nickel ternary precursor;

[0126] (10) The pH value of the second coprecipitation reaction is 10-11;

[0127] Optionally, the pH value of the second coprecipitation reaction can be 10, 10.5, 11 or any value between 10 and 11;

[0128] (11) The temperature of the second coprecipitation reaction is 40°C-60°C;

[0129] Optionally, the temperature of the second coprecipitation reaction can be 40°C, 50°C, 60°C, or any value between 40°C and 60°C;

[0130] (12) The stirring speed of the second coprecipitation reaction is 400 rpm-500 rpm.

[0131] Optionally, the stirring speed of the second coprecipitation reaction can be 400 rpm, 450 rpm, 500 rpm, or any value between 400 rpm and 500 rpm;

[0132] In some embodiments, after the second coprecipitation reaction, aging, washing, and drying are further performed, and at least one of the following conditions is met:

[0133] (1) the solid content of the material after the second coprecipitation reaction is 400 g / L-600 g / L;

[0134] Optionally, the solid content of the material after the second coprecipitation reaction can be 400 g / L, 500 g / L, 600 g / L, or any value between 400 g / L and 600 g / L;

[0135] (2) using alkali for aging, wherein the mass concentration of the alkali is 10%-20%;

[0136] Optionally, the mass concentration of the base can be 10%, 15%, 20% or any value between 10% and 20%;

[0137] (3) The aging temperature is 60°C-80°C and the time is 30min-70min;

[0138] Optionally, the aging temperature may be 60°C, 70°C, 80°C, or any value between 60°C and 80°C, and the aging time may be 30 min, 40 min, 50 min, 60 min, 70 min, or any value between 30 min and 70 min;

[0139] (4) the end point pH value of the washing is 8.0-9.0;

[0140] Optionally, the endpoint pH value of the washing may be 8.0, 8.5, 9.0, or any value between 8.0 and 9.0;

[0141] (5) The drying temperature is 100°C-140°C.

[0142] Optionally, the drying temperature may be 100°C, 110°C, 120°C, 130°C, 140°C or any value between 100°C and 140°C.

[0143] The third aspect of the present application provides a positive electrode material, including the ultra-high nickel ternary precursor or prepared by the ultra-high nickel ternary precursor preparation method.

[0144] A fourth aspect of the present application provides a lithium-ion battery comprising the aforementioned positive electrode material.

[0145] A fifth aspect of the present application provides an electrical device comprising the lithium-ion battery.

[0146] It should be noted that electrical equipment may include but is not limited to mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc.; among them, mobile devices may include but are not limited to at least one of mobile phones and laptops; electric vehicles may include but are not limited to at least one of pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.

[0147] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0148] Example 1

[0149] This embodiment provides an ultra-high nickel ternary precursor and a preparation method thereof, and the specific preparation steps include:

[0150] S1: Prepare 2 mol / L nickel, cobalt and manganese mixed metal salt solution, 10 mol / L sodium hydroxide solution and 11 mol / L ammonia water;

[0151] S2: Add 200L of pure water to a 300L reactor, introduce sodium hydroxide solution to adjust the pH value to 12.80±0.05, and introduce ammonia water to adjust the alkalinity to 5g / L to prepare a bottom liquid; then continuously introduce nitrogen into the reactor, maintain the temperature at 70°C, control the stirring speed to 700rpm, and introduce the nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water in step 1 into the reactor bottom liquid in parallel to carry out a first coprecipitation reaction, wherein the flow rate of the nickel-cobalt-manganese mixed metal salt solution is 120mL / min, and after the reaction starts, adjust the flow rate of the sodium hydroxide solution to stabilize the pH value in the reactor to 11.50±0.05, and control the ammonium ion concentration in the reactor to about 5g / L by adjusting the flow rate of the ammonia water. The reaction is terminated when the D50 of the product in the reactor reaches 4.0±0.5µm, and the product is washed and filtered to obtain a ternary precursor crystal nucleus;

[0152] S3: Add pure water to the reactor, add the crystal nuclei in step 2, and introduce ammonia solution to adjust the alkalinity in the reactor, then heat to 50°C, control the stirring speed to 500 rpm, and introduce nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia solution into the bottom liquid of the reactor in parallel to carry out the first stage reaction. The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage reaction is controlled to be 0.006%V 反应釜 / min, the particle growth rate was 0.5µm / h, the reaction time was 10h, the alkalinity was controlled at 10g / L, and the particle D50 was 9µm after the first stage reaction; then nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water were continued to be introduced for the second stage reaction, and the flow rate of nickel-cobalt-manganese mixed metal salt solution was controlled at 0.002%V 反应釜 / min, the particle growth rate was 0.3µm / h, the reaction time was 16h, the alkalinity was controlled at 20g / L, and the reaction was stopped after the D50 of the reaction product reached 13.8±0.5µm; the pH value during the first and second stage reactions was controlled at 10.50±0.05;

[0153] S4: After step 3, the solid content in the reactor is 600 g / L. The reaction product obtained in step 3 is aged, washed, filtered, and dried. A 10 wt% sodium hydroxide solution is used for aging. The aging temperature is 75 ° C. The aging reaction time is 60 min. After aging, washing is performed until the end pH value is 8.2. Then, drying is performed at 120 ° C to obtain an ultra-high nickel ternary precursor with a molecular formula of Ni 0.94 Co 0.03 Mn 0.03 (OH)2.

[0154] The tap density of the obtained ultra-high nickel ternary precursor is 2.04 g / cm 3 , with a specific surface area of ​​8.5m 2 / g.

[0155] The width of the primary particles of the ultra-high nickel ternary precursor is marked by SEM. Figure 1 As shown, the length of the primary particles is marked with SEM as Figure 2 shown.

[0156] Example 2

[0157] This embodiment provides an ultra-high nickel ternary precursor and a preparation method thereof, and the specific preparation steps include:

[0158] S1: Prepare 2 mol / L nickel, cobalt and manganese mixed metal salt solution, 10 mol / L sodium hydroxide solution and 11 mol / L ammonia water;

[0159] S2: Add 200 L of pure water to a 300 L reactor, introduce sodium hydroxide solution to adjust the pH value to 12.05 ± 0.05, and introduce ammonia water to adjust the alkalinity to 2 g / L to prepare a bottom liquid; then continuously introduce nitrogen into the reactor, maintain the temperature at 60 ° C, control the stirring speed to 600 rpm, and introduce the nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water in step 1 into the reactor bottom liquid in parallel to carry out a first coprecipitation reaction, wherein the nickel-cobalt-manganese mixed metal salt solution flow rate is 120 mL / min, and after the reaction starts, adjust the sodium hydroxide solution flow rate to stabilize the pH value in the reactor to 11.20 ± 0.05, and control the ammonium ion concentration in the reactor to about 10 g / L by adjusting the flow rate of ammonia water. The reaction is terminated when the D50 of the product in the reactor reaches 4.0 ± 0.5 μm, and the product is washed and filtered to obtain a ternary precursor crystal nucleus;

[0160] S3: Add pure water to the reactor, add the crystal nuclei in step 2, and introduce ammonia solution to adjust the alkalinity in the reactor, then heat to 45°C, control the stirring speed to 500 rpm, and introduce nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia solution into the bottom liquid of the reactor in parallel to carry out the first stage reaction. The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage reaction is controlled to be 0.004%V 反应釜 / min, the particle growth rate was 0.4µm / h, the reaction time was 12.5h, the alkalinity was controlled at 10g / L, and the particle D50 was 9µm after the first stage reaction. Then, nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water were continued to be introduced for the second stage reaction, and the flow rate of nickel-cobalt-manganese mixed metal salt solution was controlled at 0.002%V 反应釜 / min, the particle growth rate was 0.15µm / h, the reaction time was 33h, the alkalinity was controlled at 15g / L, and the reaction was stopped after the D50 of the reaction product reached 13.8±0.5µm; the pH value during the first and second stage reactions was controlled at 10.8±0.5;

[0161] S4: After step 3, the solid content in the reactor is 400 g / L. The reaction product obtained in step 3 is aged, washed, filtered, and dried. A 10 wt% sodium hydroxide solution is used for aging. The aging temperature is 75 ° C. The aging reaction time is 60 min. After aging, washing is performed until the end pH value is 8.0. Then, drying is performed at 120 ° C to obtain an ultra-high nickel ternary precursor with a molecular formula of Ni 0.90 Co 0.03 Mn 0.07 (OH)2.

[0162] The tap density of the obtained ultra-high nickel ternary precursor is 1.95 g / cm 3 .

[0163] The specific surface area of ​​the obtained ultra-high nickel ternary precursor is 10.2m 2 / g.

[0164] The width of the primary particles of the ultra-high nickel ternary precursor is marked by SEM. Figure 3 shown.

[0165] The length of the primary particles of the ultra-high nickel ternary precursor is marked by SEM. Figure 4 shown.

[0166] Example 3

[0167] This embodiment provides an ultra-high nickel ternary precursor and a preparation method thereof, and the specific preparation steps include:

[0168] S1: Prepare 2 mol / L nickel, cobalt and manganese mixed metal salt solution, 10 mol / L sodium hydroxide solution and 11 mol / L ammonia water;

[0169] S2: Add 200 L of pure water to a 300 L reactor, introduce sodium hydroxide solution to adjust the pH value to 12.95 ± 0.05, and introduce ammonia water to adjust the alkalinity to 8 g / L to prepare a bottom liquid; then continuously introduce nitrogen into the reactor, maintain the temperature at 80 ° C, control the stirring speed to 600 rpm, and introduce the nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water in step 1 into the reactor bottom liquid in parallel to carry out a first coprecipitation reaction, wherein the flow rate of the nickel-cobalt-manganese mixed metal salt solution is 120 mL / min, and after the reaction starts, adjust the flow rate of the sodium hydroxide solution to stabilize the pH value in the reactor to 11.10 ± 0.05, and control the ammonium ion concentration in the reactor to about 8 g / L by adjusting the flow rate of ammonia water. The reaction is terminated when the D50 of the product in the reactor reaches 4.0 ± 0.5 µm, and the product is washed and filtered to obtain a ternary precursor crystal nucleus;

[0170] S3: Add pure water to the reactor, add the crystal nuclei in step 2, and introduce ammonia solution to adjust the alkalinity in the reactor, then heat to 60°C, control the stirring speed to 400 rpm, and introduce nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia solution into the bottom liquid of the reactor in parallel to carry out the first stage reaction. The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage reaction is controlled to be 0.004%V 反应釜 / min, the particle growth rate was 0.6µm / h, the reaction time was 8.3h, the alkalinity was controlled at 12g / L, and the particle D50 was 9µm after the first stage reaction; then nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water were continued to be introduced for the second stage reaction, and the flow rate of nickel-cobalt-manganese mixed metal salt solution was controlled at 0.002%V 反应釜 / min, the particle growth rate was 0.25µm / h, the reaction time was 20h, the alkalinity was controlled at 18g / L, and the reaction was stopped after the D50 of the reaction product reached 14.0±0.5µm. The pH value during the first and second stage reactions was controlled at 10.20±0.5.

[0171] S4: After step 3, the solid content in the reactor is 600 g / L. The reaction product obtained in step 3 is aged, washed, filtered, and dried. A 10 wt% sodium hydroxide solution is used for aging. The aging temperature is 75 ° C. The aging reaction time is 60 min. After aging, washing is performed until the end pH value is 8.2. Then, drying is performed at 120 ° C to obtain an ultra-high nickel ternary precursor with a molecular formula of Ni 0.96 Co 0.02 Mn 0.02 (OH)2.

[0172] The tap density of the obtained ultra-high nickel ternary precursor is 1.91 g / cm 3 , with a specific surface area of ​​11.1m 2 / g.

[0173] Example 4

[0174] The difference from Example 1 is that the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage of step S3 is controlled to be 0.008%V 反应釜 / min, the particle growth rate is 0.6µm / h, and the reaction time is 8.3h; the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is controlled to be 0.002%V 反应釜 / min, the particle growth rate is 0.3µm / h, and the reaction time is 16h.

[0175] Example 5

[0176] The difference from Example 1 is that the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage of step S3 is controlled to be 0.003%V 反应釜 / min, the particle growth rate is 0.25µm / h, and the reaction time is 20h; the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is controlled to be 0.001%V 反应釜 / min, the particle growth rate was 0.15µm / h, and the reaction time was 32h.

[0177] Comparative Example 1

[0178] This comparative example provides an ultra-high nickel ternary precursor and a preparation method thereof, and the specific preparation steps include:

[0179] S1: Prepare 2 mol / L nickel, cobalt and manganese mixed metal salt solution, 10 mol / L sodium hydroxide solution and 11 mol / L ammonia water;

[0180] S2: Add 200L of pure water to a 300L reactor, introduce sodium hydroxide solution to adjust the pH value to 12.80±0.05, and introduce ammonia water to adjust the alkalinity to 5g / L to prepare a bottom liquid; then continuously introduce nitrogen into the reactor, maintain the temperature at 70°C, control the stirring speed to 700rpm, and introduce the nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia water in step 1 into the reactor bottom liquid in parallel to carry out a first coprecipitation reaction, wherein the flow rate of the nickel-cobalt-manganese mixed metal salt solution is 120mL / min, and after the reaction starts, adjust the flow rate of the sodium hydroxide solution to stabilize the pH value in the reactor to 11.50±0.05, and control the ammonium ion concentration in the reactor to about 5g / L by adjusting the flow rate of the ammonia water. The reaction is terminated when the D50 of the product in the reactor reaches 4.0±0.5µm, and the product is washed and filtered to obtain a ternary precursor crystal nucleus;

[0181] S3: Add pure water to the reactor, add the crystal nuclei in step 2, and introduce ammonia solution to adjust the alkalinity in the reactor, then heat to 50°C, control the stirring speed to 500 rpm, and introduce nickel-cobalt-manganese mixed metal salt solution, sodium hydroxide solution and ammonia solution into the bottom liquid of the reactor in parallel to carry out the second coprecipitation reaction, and control the flow rate of nickel-cobalt-manganese mixed metal salt solution to 0.006%V 反应釜 / min, the particle growth rate was 0.6µm / h, the reaction time was 17h, the alkalinity was controlled at 15g / L, the pH value was controlled at 10.50±0.05, and the reaction was stopped after the D50 of the reaction product reached 14.2±0.5µm;

[0182] S4: After step 3, the solid content in the reactor is 510 g / L. The reaction product obtained in step 3 is aged, washed, filtered, and dried. A 10 wt% sodium hydroxide solution is used for aging. The aging temperature is 75 ° C. The aging reaction time is 60 min. After aging, washing is performed until the end pH value is 8.2. Then, drying is performed at 120 ° C to obtain an ultra-high nickel ternary precursor with a molecular formula of Ni 0.94 Co 0.03 Mn 0.03 (OH)2.

[0183] The tap density of the obtained ultra-high nickel ternary precursor is 1.88 g / cm 3 , with a specific surface area of ​​15.1m 2 / g.

[0184] The width of the primary particles of the ultra-high nickel ternary precursor is marked by SEM. Figure 5 The length of the primary particles shown is marked with SEM. Figure 6 shown.

[0185] Comparative Example 2

[0186] The difference from Example 1 is that the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage of step S3 is controlled to be 0.008%V 反应釜 / min, the particle growth rate is 0.6µm / h, and the reaction time is 8.3h; the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is controlled to be 0.001%V 反应釜 / min, the particle growth rate was 0.15µm / h, and the reaction time was 32h.

[0187] Comparative Example 3

[0188] The difference from Example 1 is that the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage of step S3 is controlled to be 0.002%V 反应釜 / min, the particle growth rate is 0.2µm / h, and the reaction time is 25h; the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is controlled to be 0.002%V 反应釜 / min, the particle growth rate is 0.2µm / h, and the reaction time is 25h.

[0189] Comparative Example 4

[0190] The difference from Example 1 is that the alkalinity in the first stage of step S3 is controlled to be 12 g / L; the alkalinity in the second stage is controlled to be 15 g / L.

[0191] The relevant parameters of the ultra-high nickel ternary precursors prepared in the above examples and comparative examples are shown in Table 1.

[0192] Table 1 Related parameters

[0193]

[0194] For all of the above examples and comparative samples, lithium hydroxide and a high-nickel precursor were solid-phase mixed in a high-pressure mixer at a molar ratio of 1.06:1 and sintered at 670°C for 6 hours to produce a high-nickel positive electrode material. This high-nickel positive electrode material was electrochemically tested using a coin-cell battery: the above-mentioned positive electrode material, conductive carbon black, and binder PVDF (polyvinylidene fluoride) were mixed into a slurry at a ratio of 8.5:1.5:1.5 and coated onto aluminum foil to form a positive electrode sheet. A metallic lithium sheet was used as the negative electrode sheet, and the electrolyte used was 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1). In a vacuum glove box, the battery case, positive and negative electrode sheets, separator, spring, and gasket were assembled into a button cell. Electrochemical performance testing was conducted using a blue electric test system. 1C / 1C charge / discharge capacity and initial coulombic efficiency were measured at 2.8-4.25V and 25°C. Specific test results are shown in Table 2.

[0195] Table 2 Electrochemical performance test

[0196]

[0197] Analysis: From the above tests, it can be seen that the battery processed by the precursor produced by the technical solution of this application has better performance in charging capacity, charge and discharge capacity, and first coulombic efficiency.

[0198] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0199] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and to form distinct embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of this application and should not be construed as an admission or any implication that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing an ultra-high nickel ternary precursor, characterized in that: The chemical formula of the ultra-high nickel ternary precursor is Ni x Co y Mn 1-x-y (OH)2, 0.90≤x≤0.96, 0<y≤0.03; The average length and average width of the primary particles satisfy: Average length: average width = 2-4:1; The method for preparing the ultra-high nickel ternary precursor comprises: introducing a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution and ammonia water into a base liquid containing a sodium hydroxide solution and ammonia water under a protective atmosphere, and performing a first coprecipitation reaction to obtain a seed crystal; Mixing the seed crystals, water, and aqueous ammonia to obtain a mixture, and introducing a nickel-cobalt-manganese mixed metal salt solution, a sodium hydroxide solution, and aqueous ammonia into the mixture to perform a second coprecipitation reaction to obtain an ultra-high nickel ternary precursor; The second coprecipitation reaction includes a first stage and a second stage performed sequentially, wherein the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is greater than the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage; The ratio of the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage to the flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 2-4:1; The ratio of the alkalinity in the first stage to the alkalinity in the second stage is 1:1.5-2; The D50 of the particles prepared in the first stage is 0.5 to 0.7 times the target D50 of the ultra-high nickel ternary precursor.

2. The method for preparing the ultra-high nickel ternary precursor according to claim 1, characterized in that: At least one of the following conditions is met: (1) The average length of the primary particles is 0.5 μm-1.0 μm, and the average width of the primary particles is 0.2 μm-0.4 μm; (2) The D50 of the ultra-high nickel ternary precursor is 10 μm-20 μm.

3. The method for preparing the ultra-high nickel ternary precursor according to claim 1, characterized in that: At least one of the following conditions is met: (1) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the first stage is 0.003%V 反应釜 / min-0.008%V 反应釜 / min; (2) The flow rate of the nickel-cobalt-manganese mixed metal salt solution in the second stage is 0.001%V 反应釜 / min-0.002%V 反应釜 / min; (3) The growth rate of the particles in the first stage is 0.4 μm / h-0.6 μm / h; (4) The duration of the first stage is 5h-15h; (5) The alkalinity in the first stage is 10 g / L-12 g / L; (6) The growth rate of the particles in the second stage is 0.1 μm / h-0.4 μm / h; (7) The duration of the second stage is 20h-40h; (8) The alkalinity in the second stage is 15 g / L-20 g / L.

4. The method for preparing the ultra-high nickel ternary precursor according to claim 1, characterized in that: At least one of the following conditions is met: (1) the total metal molar concentration in the nickel-cobalt-manganese mixed metal salt solution is 1.0 mol / L-2.5 mol / L; (2) the molar concentration of the sodium hydroxide solution is 5 mol / L-10 mol / L; (3) the molar concentration of ammonium ions in the ammonia water is 6 mol / L-12 mol / L; (4) The pH value of the base solution is 12-13; (5) The alkalinity of the base solution is 2 g / L-10 g / L; (6) The pH value of the first coprecipitation reaction is 11-12; (7) The temperature of the first coprecipitation reaction is 60° C.-80° C.; (8) The stirring speed of the first coprecipitation reaction is 600 rpm-700 rpm; (9) The D50 of the seed crystal is 0.2 to 0.4 times the target D50 of the ultra-high nickel ternary precursor; (10) The pH value of the second coprecipitation reaction is 10-11; (11) The temperature of the second coprecipitation reaction is 40°C-60°C; (12) The stirring speed of the second coprecipitation reaction is 400 rpm-500 rpm.

5. The method for preparing the ultra-high nickel ternary precursor according to any one of claims 1 to 4, characterized in that: After the second coprecipitation reaction, aging, washing, and drying are further performed, and at least one of the following conditions is met: (1) the solid content of the material after the second coprecipitation reaction is 400 g / L-600 g / L; (2) using alkali for aging, wherein the mass concentration of the alkali is 10%-20%; (3) The aging temperature is 60°C-80°C and the time is 30min-70min; (4) the end point pH value of the washing is 8.0-9.0; (5) The drying temperature is 100°C-140°C.

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