Positive electrode material precursor, preparation method thereof, positive electrode material and lithium ion battery

Abstract

The present invention provides a cathode material precursor, a preparation method thereof, a cathode material, and a lithium-ion battery. The primary particles of the cathode material precursor comprise multi-layered sheets, with an average number of sheets of 5 to 30, each with a thickness of 5 to 15 nm. The structure design facilitates the insertion, desorption, and diffusion of lithium ions into the cathode material, significantly improving the conductivity of lithium ions and further enhancing the capacity and cycle performance of the cathode material.

Description

[Technical Field]

[0001] The present disclosure belongs to the technical field of lithium ion batteries, and in particular relates to a positive electrode material precursor, a preparation method thereof, a positive electrode material, and a lithium ion battery.

[0002] (CROSS-REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to a Chinese application filed with the State Intellectual Property Office of the People's Republic of China on December 30, 2022, bearing application number 202211735640.8 and entitled "Positive electrode material precursor, preparation method thereof, positive electrode material and lithium ion battery," the entire contents of which are incorporated herein by reference. [Background technology]

[0003] With the development of new energy industry, lithium battery technology is becoming more and more mature. Among various lithium batteries, ternary lithium batteries have significant advantages such as high energy density, excellent cycle performance, and better low temperature resistance, and are therefore widely used in the field of new energy automobiles.

[0004] The positive electrode material of a ternary lithium battery is a factor that affects its performance. The preparation process for the positive electrode material typically involves coprecipitation to prepare a positive electrode precursor, which is then further processed to obtain the positive electrode material. Current positive electrode materials have the following main problems: Due to factors such as the crystalline structure and the irregular arrangement of Li / Ni within the battery, lithium ions are difficult to desorb. As a result, the initial discharge specific capacity and initial coulombic efficiency of the positive electrode material are relatively low. Furthermore, the relatively long lithium ion migration path and low lithium ion conductivity make lithium ion insertion and desorption difficult, resulting in poor cycle performance. Summary of the Invention

[0005] In view of the above, the present disclosure provides a cathode material precursor, a preparation method thereof, a cathode material, and a lithium-ion battery, which can solve the problem in the prior art of cathode materials in lithium-ion batteries, in which the specific capacity and cycle performance decrease due to low conductivity caused by an excessively long lithium ion migration path.

[0006] The present disclosure first provides a positive electrode material precursor. The primary particles of the positive electrode material precursor include multiple layers of sheets, with the average number of sheets being 5 to 30 and each sheet having a thickness of 5 to 15 nm. For example, the average number of sheets may be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or any value within the range of 5 to 30. Preferably, the average number of sheets is 8 to 25. The thickness of each sheet may be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or any value within the range of 5 to 15 nm. Preferably, the thickness of each sheet is 5 to 12 nm, more preferably 7 to 12 nm, and even more preferably 7 to 11.5 nm. The present disclosure provides a cathode material precursor. The primary particles of the cathode material precursor include multiple layers of sheets, each with a thickness of 5 to 15 nm, and an average number of sheets in the primary particles of 5 to 30. If the average number of sheets is too small and the sheet thickness is too thin, the overall thickness of the primary particles of the resulting cathode material precursor is too thin, making side reactions between the material and the electrolyte more likely to occur and reducing the safety performance of the resulting battery. Furthermore, if the sheets are too thin, the lithium ion transport pathways become too narrow, resulting in reduced lithium ion conductivity. If the average number of sheets is too large and the sheet thickness is too thick, the resulting primary particles of the cathode material precursor are too thick, reducing the reaction area between the material and the electrolyte. If the thickness of each sheet is too thick, each sheet will directly form a primary particle. In this case, the resulting primary particles will have relatively low strength and will not maintain their integrity under high temperature and high voltage conditions after being prepared into a battery positive electrode, which will be detrimental to the battery's cycle performance.

[0007] In the present disclosure, by setting the thickness and average number of the sheets within the above ranges, the strength of the primary particles of the cathode material precursor is stabilized, and after preparation into a battery cathode, the integrity of the primary particles can be maintained even under high temperature and high voltage conditions, thereby ensuring the cycle performance of the battery.In addition, a relatively wide and relatively short path can be provided for the transport of lithium ions, which contributes to the transport of lithium ions, prevents a decrease in lithium ion conductivity, and maximizes the excellent capacity performance and long cycle performance of the battery. Preferably, the average number of sheets is 5 to 30, and the thickness of each sheet is 5 to 12 nm. Preferably, the average number of said sheets is 8 to 25, and the thickness of each of said sheets is 7 to 12 nm. Preferably, the average number of sheets is 8 to 25, and the thickness of each sheet is 7 to 11.5 nm. When the thickness and average number of sheets are within this range, the battery prepared with the corresponding positive electrode material has a higher capacity and better cycle performance. Preferably, the primary particles of the positive electrode material precursor are formed by laminating a plurality of sheets. Preferably, the stacked primary particles are elongated, and the particle width of the primary particles is 30 to 150 nm, preferably 30 to 110 nm, the particle length of the primary particles is 400 to 800 nm, and the aspect ratio of the primary particles is 2.0 to 13.0, preferably 4.0 to 13.0. For example, the particle width of the primary particles is 30 nm, 31 nm, 32 nm, 33 nm, 35 nm, 37 nm, 39 nm, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm, 60 nm, 62 nm, 64 nm, 64.5 nm, 68 nm, 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, 82 nm, 84 nm, 86 nm, 88 nm, 90 nm, 92 nm, 94 nm, 96 nm, 100 nm, 102 nm, 104 nm, 106 nm, 108 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, or any value in the range of 30 to 150 nm. The length of the primary particles is 400 nm, 430 nm, 450 nm, 470 nm, 475 nm, 480 nm, 490 nm, 500 nm, 530 nm, 550 nm, 600 nm, 650 nm, 700 nm, 720 nm, 730 nm, 750 nm, 770 nm, 790 nm, 800 nm, or any value in the range of 400 to 800 nm. The aspect ratio of the primary particles is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or any value in the range of 2 to 13. In the present disclosure, the primary particles having an appropriate aspect ratio can contribute to improving the capacity performance and cycle performance of the positive electrode material prepared from the positive electrode material precursor. In the present disclosure, the particle length of a primary particle is obtained by measuring the longest distance between any two points on the primary particle in an SEM photograph, and the particle width of a primary particle is obtained by measuring the longest distance in a direction perpendicular to the length direction of the primary particle.

[0008] In an alternative embodiment of the present disclosure, the cathode material precursor has the formula Ni x Co y M zIt is (OH)₂, provided that x + y + z = 1, 0.7 ≤ x < 1, 0 ≤ y ≤ 0.3, and 0 < z ≤ 0.3, and M is at least one selected from Mg, Sr, Ba, B, Al, Si, Mn, Ti, Zr, and W. Since the nickel content of the components in the cathode material precursor is 70% or more, it can contribute to the improvement of the capacity of the cathode material.

[0009] In an alternative embodiment of the present disclosure, in the XRD pattern of the cathode material precursor, the peak intensity ratio of I(101) to I(001) is 1.05 to 1.5. The sheets of the primary particles in the cathode material precursor according to the present disclosure have appropriate thicknesses and numbers, and the peak intensity ratio of the cathode material precursor in the XRD pattern of the cathode material precursor is 1.05 to 1.5. In this case, the growth on the (101) plane affects the thickness of the sheet. In the present disclosure, since the peak intensity ratio of I(101) to I(001) is high, the sheet tends to grow along the (101) plane rather than the (001) plane. Each thickness of the sheet is maintained within the range of 5 to 12 nm under the influence of the growth on the (101) plane of the cathode material precursor. According to the preferential growth of the sheet on the (101) plane, the lithium ion transport path on the (001) plane can be shortened, and the lithium ion transport path in the cathode material precursor can be widened, so that the lithium ion conductivity can be increased, and the electrical performance such as the capacity performance and cycle performance of the cathode material can be improved.

[0010] Since the cathode material precursor preferentially grows along the (101) plane, it can contribute to widening the lithium ion transport path, reducing the dimension of the (001) plane, shortening the lithium ion conduction path on the (001) plane, and increasing the lithium ion conductivity.

[0011] In an alternative embodiment of the present disclosure, in the XRD pattern of the positive electrode material precursor, the half width of the (001) plane is 0.40° to 0.65°, and the half width of the (101) plane is 0.45° to 0.60°. For example, in the XRD pattern of the positive electrode material precursor, the (001) plane half-width is 0.40°, 0.41°, 0.42°, 0.43°, 0.44°, 0.45°, 0.46°, 0.47°, 0.48°, 0.49°, 0.50°, 0.51°, 0.52°, 0.53°, 0.54°, 0.55°, 0.56°, 0.57°, 0.58°, 0.59°, 0.60°, 0.61°, 0.62°, 0.63°, 0.64°, 0.65°, or any value in the range of 0.40° to 0.65°. For example, the (101) plane FWHM is 0.45°, 0.46°, 0.47°, 0.48°, 0.49°, 0.50°, 0.51°, 0.52°, 0.53°, 0.54°, 0.55°, 0.56°, 0.57°, 0.58°, 0.59°, 0.60°, or any value in the range of 0.45° to 0.60°. The positive electrode material precursor has a relatively narrow FWHM and high crystallinity, which can contribute to improving the cycle performance of the positive electrode material.

[0012] In an alternative embodiment of the present disclosure, the porosity of the positive electrode material precursor is 2% to 14%. For example, the porosity of the positive electrode material precursor is 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or any value in the range of 2% to 14%. Preferably, the porosity of the positive electrode material precursor is 3% to 12%, and more preferably, the porosity of the positive electrode material precursor is 3 to 10%. Having an appropriate porosity promotes electrolyte penetration without sacrificing cycle performance, allows the secondary particles to better fulfill their role as internal sheets, and further improves capacity.

[0013] In an alternative embodiment of the present disclosure, the positive electrode material precursor has a D50 of 2 to 18 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, or any value in the range of 2 to 18 μm. A second aspect of the present disclosure further provides a method for preparing the above-mentioned cathode material precursor, the method including the steps of preparing a metal salt solution, a precipitating agent, and a complexing agent, and mixing the metal salt solution, the precipitating agent, and the complexing agent to perform a co-precipitation reaction to obtain the cathode material precursor.

[0014] Furthermore, the step of mixing a metal salt solution, a precipitating agent, and a complexing agent to perform a co-precipitation reaction to obtain a positive electrode material precursor specifically includes the steps of mixing a precipitating agent, a complexing agent, and pure water to obtain a first base solution, and adding the metal salt solution, the complexing agent, and the precipitating agent to the first base solution to perform a first co-precipitation reaction to obtain a positive electrode material precursor.

[0015] Furthermore, the step of mixing the metal salt solution, the precipitating agent, and the complexing agent to perform a co-precipitation reaction to obtain a positive electrode material precursor specifically includes the steps of mixing the precipitating agent, the complexing agent, and pure water to obtain a first base solution, adding the metal salt solution, the complexing agent, and the precipitating agent to the first base solution to perform a first co-precipitation reaction to obtain a first metal hydroxide, and mixing the first metal hydroxide, pure water, the precipitating agent, and the complexing agent to obtain a second base solution, adding the metal salt solution, the complexing agent, and the precipitating agent to the second base solution to perform a second co-precipitation reaction to obtain a positive electrode material precursor.

[0016] Furthermore, in the step of preparing the metal salt solution, precipitant, and complexing agent, the metal salt solution has a concentration of 1.0 to 2.0 mol / L, the precipitant contains an aqueous sodium hydroxide solution with a concentration of 5 to 12 mol / L, the complexing agent contains an aqueous ammonia solution with a concentration of 1 to 10 mol / L, the flow rate of the metal salt solution added to the first or second base solution is 4.0% to 7.5% / h of the total volume of the reaction vessel, the pH value of the first base solution is 11 to 12, and the ammonia concentration in the reaction system is 2 to 5 g / L. Preferably, the metal salt solution is prepared using soluble salt solutions of nickel, cobalt, and manganese, respectively, and the soluble salts include at least one of nitrate, chloride, and sulfate.

[0017] Furthermore, the pH value of the second base solution is 10 to 11, and the ammonia concentration in the reaction system is 2 to 6 g / L, and preferably the ammonia concentration in the reaction system is 3 to 6 g / L.

[0018] A third aspect of the present disclosure further provides a positive electrode material, which is prepared from the above-described positive electrode material precursor.

[0019] A fourth aspect of the present disclosure further provides a lithium-ion battery, the lithium-ion battery including the positive electrode material described above.

[0020] The primary particles of the cathode material precursor according to the present disclosure include multiple layers of sheets, each having a thickness of 5 to 15 nm, and an average number of sheets in the primary particles of 5 to 30. In the present disclosure, by setting the thickness and average number of sheets within the above ranges, the strength of the primary particles of the cathode material precursor is stable, and after preparation into a battery cathode, the integrity of the primary particles is maintained even under high temperature and high voltage conditions, thereby ensuring the cycle performance of the battery. Sheets with an appropriate number and thickness ranges ensure the appropriate width of the primary particles, thereby reducing side reactions between the cathode material and the electrolyte and improving the safety of the prepared battery. Furthermore, sheets with an appropriate number and thickness ranges ensure the strength of the material and prevent the lithium ion transport pathway from becoming too narrow. This contributes to lithium ion transport and prevents a decrease in lithium ion conductivity. Therefore, the electric capacity of the cathode material prepared from the cathode material precursor is higher and the cycle performance is superior.

[0021] The method for preparing a cathode material precursor according to the present disclosure controls the growth of the cathode material precursor during the co-precipitation reaction by adjusting reaction conditions such as the flow rate of the solution, the pH value of the reaction system, and the ammonia concentration, etc. Therefore, batteries prepared using the corresponding cathode material precursor have high capacity and excellent cycle performance.

[0022] Other features and advantages of the present disclosure are further described in the specific embodiments that follow. In order to more clearly describe the specific embodiments of the present disclosure or the technical solutions in the prior art, the following will briefly describe the drawings used in the specific embodiments or the prior art. The drawings described are for illustrating some examples of the present disclosure. Those skilled in the art can obtain other drawings based on these drawings without using inventive ability. [Brief explanation of the drawings]

[0023] [Figure 1a] 1 is an SEM photograph of an exemplary cathode material precursor sample 1 according to the present disclosure. [Figure 1a-1] 1 is an SEM photograph of an exemplary cathode material precursor sample 1 according to the present disclosure. [Figure 1a-2] 1 is a CP photograph (cross-section polisher photograph) of an exemplary positive electrode material precursor sample 1 according to the present disclosure. [Figure 1b] 1a is a partially enlarged SEM photograph of the positive electrode material precursor sample 1 shown in FIG. [Figure 1b-1] 1a is a partially enlarged SEM photograph of the positive electrode material precursor sample 1 shown in FIG. [Figure 1c] 1 is an XRD pattern of an exemplary cathode material precursor Sample 1 according to the present disclosure. [Figure 2a] 1 is an SEM photograph of an exemplary cathode material precursor sample 2 according to the present disclosure. [Figure 2b] 2a is a partially enlarged SEM photograph of the positive electrode material precursor sample 2 shown in FIG. 2a. [Figure 2c] 1 is an XRD pattern of an exemplary cathode material precursor Sample 2 according to the present disclosure. [Figure 3a] 1 is an SEM photograph of an exemplary cathode material precursor sample 3 according to the present disclosure. [Figure 3b] 3a is a partially enlarged SEM photograph of the positive electrode material precursor sample 3 shown in FIG. 3a. [Figure 4a] 1 is an SEM photograph of an exemplary cathode material precursor sample 4 according to the present disclosure. [Figure 4b]4a is a partially enlarged SEM photograph of the positive electrode material precursor sample 4 shown in FIG. 4a. [Figure 4c] 1 is an XRD pattern of an exemplary cathode material precursor Sample 4 according to the present disclosure. [Figure 5a] 1 is an SEM photograph of an exemplary cathode material precursor sample 5 according to the present disclosure. [Figure 5b] FIG. 5a is a partially enlarged SEM photograph of the positive electrode material precursor sample 5 shown in FIG. [Figure 5c] 1 is an XRD pattern of an exemplary cathode material precursor Sample 5 according to the present disclosure. [Figure 6a] 1 is an SEM photograph of an exemplary cathode material precursor Sample 9 according to the present disclosure. [Figure 6b] 6a is a partially enlarged SEM photograph of the positive electrode material precursor sample 9 shown in FIG. 6a. [Figure 6c] 1 is an XRD pattern of an exemplary cathode material precursor Sample 9 according to the present disclosure. [Figure 7] 1 is an SEM photograph of an exemplary cathode material precursor Sample 11 according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] To make the above and other features and advantages of the present disclosure more apparent, the present disclosure will be further described below with reference to the drawings. The specific examples described herein are for the purpose of explanation to those skilled in the art and are intended to be illustrative only and not limiting.

[0025] In the positive electrode material precursor according to the present disclosure, the primary particles of the positive electrode material precursor include sheets of multiple layers, the average number of sheets is 5 to 30, and the thickness of each sheet is 5 to 15 nm.

[0026] The cathode material precursor according to the present disclosure can increase the capacity of a lithium battery prepared with the corresponding cathode material by controlling the thickness and number of primary particle sheets within an appropriate range. The appropriate thickness and number of sheets can shorten the lithium ion conduction path and widen the transport path, making lithium ion insertion and desorption easier and significantly improving lithium ion conductivity. Furthermore, sheets within the appropriate number and thickness ranges can ensure the strength of the material, thereby improving the cycle performance of a lithium battery prepared with the corresponding cathode material. The cathode material precursor according to the present disclosure includes a plurality of secondary particles, each of which is composed of a plurality of primary particles, and each of which is composed of a plurality of the sheets stacked together.

[0027] Based on the above inventive concept, the present disclosure further provides a method for preparing a cathode material precursor, which mainly includes the steps of preparing a metal salt solution, a precipitating agent, and a complexing agent, mixing the precipitating agent, complexing agent, and pure water to obtain a first base solution, adding the metal salt solution, complexing agent, and precipitating agent to the first base solution to perform a first co-precipitation reaction to obtain a first metal hydroxide, and mixing the first metal hydroxide, pure water, precipitating agent, and complexing agent to obtain a second base solution, adding the metal salt solution, complexing agent, and precipitating agent to the second base solution to perform a second co-precipitation reaction to obtain a cathode material precursor.

[0028] In an alternative embodiment of the present disclosure, a precipitating agent, a complexing agent, and pure water are mixed to obtain a first base solution, and a metal salt solution, a complexing agent, and a precipitating agent are added to the first base solution to perform a first co-precipitation reaction, after which a positive electrode material precursor can be directly obtained.

[0029] In the above preparation method, when the coprecipitation reaction is carried out, the flow rate of each solution, the ammonia concentration, and the pH value of the reaction system are controlled to control the growth of the positive electrode material precursor during the reaction process, thereby controlling the morphology of the positive electrode material precursor, and the primary particles of the obtained positive electrode material precursor mainly comprise the above multi-layer sheets.

[0030] The following specific examples further illustrate the cathode material precursor and its preparation method according to the present disclosure.

[0031] [Example 1] The cathode material precursor sample 1 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 (OH)2 and was prepared by the following method: Using sulfate solutions of nickel, cobalt, and manganese, a nickel-cobalt-manganese solution with a concentration of 2.0 mol / L was prepared in a molar ratio of Ni:Co:Mn = 94:5:1. A sodium hydroxide solution with a concentration of 5.5 mol / L was prepared as a precipitant, and an aqueous ammonia solution with a concentration of 5 mol / L was prepared as a complexing agent.

[0032] Sodium hydroxide solution, aqueous ammonia, and water were mixed and placed in a reactor and stirred uniformly under constant temperature conditions to obtain a first base solution with a pH of 11-11.60. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the added aqueous ammonia was 21 wt%. For protection, an inert gas was introduced into the first base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese solution, aqueous ammonia, and sodium hydroxide solution into the reactor containing the first base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese solution were 4% / h, the aqueous ammonia solution was 0.15% / h, and the sodium hydroxide solution was 1.48% / h. Under stirring conditions of a constant temperature of 65°C and a rotation speed of 150 r / min, a first coprecipitation reaction was carried out to produce the first nickel-cobalt-manganese hydroxide. During the first coprecipitation reaction, the nickel-cobalt-manganese solution, aqueous ammonia solution, and sodium hydroxide solution were continuously supplied and discharged. The amount of material discharged was the same as the total amount of material supplied. During the reaction, the flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH of the first coprecipitation reaction system within the range of 11.50 to 11.70, and the ammonia concentration was controlled to fluctuate within the range of 4 to 4.5 g / L, thereby stabilizing the particle size. After the first coprecipitation reaction stabilized, the first nickel-cobalt-manganese hydroxide was obtained.

[0033] The first nickel-cobalt-manganese hydroxide was used as a seed crystal and placed in a reactor together with pure water, sodium hydroxide solution, and aqueous ammonia solution. The mixture was stirred uniformly at a constant temperature to obtain a second base solution with a pH of 10.50-10.80. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the aqueous ammonia solution was 21 wt%. For protection, an inert gas was introduced into the second base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution into the reactor containing the second base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 6% / h, the aqueous ammonia solution 0.2% / h, and the sodium hydroxide solution 2.22% / h. The first nickel-cobalt-manganese hydroxide was grown via a second coprecipitation reaction under stirring conditions of a constant temperature of 65°C and a rotation speed of 150 r / min. During the second coprecipitation reaction, the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution were continuously supplied and discharged. The discharged and total supplied amounts of materials were the same. During the second coprecipitation reaction, the flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH value of the second coprecipitation reaction system within the range of 10.40-10.60, and the ammonia concentration was controlled to fluctuate within the range of 4-4.5 g / L. The particle size was maintained stable by continuously adding the first nickel-cobalt-manganese hydroxide. After the second coprecipitation reaction stabilized, the second nickel-cobalt-manganese hydroxide was obtained.

[0034] The second nickel cobalt manganese hydroxide was centrifuged, washed, dried and sieved to obtain a positive electrode material precursor sample 1.

[0035] [Example 2] The cathode material precursor sample 2 has the chemical formula Ni 0.92 Co 0.07 Mn 0.01 (OH)2 and was prepared by the following method:

[0036] Using sulfate solutions of nickel, cobalt, and manganese, a nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared in a molar ratio of Ni:Co:Mn=92:7:1. A sodium hydroxide solution with a concentration of 5.5 mol / L was prepared as a precipitant, and an ammonia aqueous solution with a concentration of 5 mol / L was prepared as a complexing agent.

[0037] Sodium hydroxide solution, aqueous ammonia, and water were mixed and placed in a reactor and stirred uniformly under constant temperature conditions to obtain a first base solution with a pH of 11 to 11.60. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the added aqueous ammonia was 21 wt%. For protection, an inert gas was introduced into the first base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, aqueous ammonia, and sodium hydroxide solution into the reactor containing the first base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 4% / h, the aqueous ammonia solution 0.20% / h, and the sodium hydroxide solution 1.48% / h. Under stirring conditions of a constant temperature of 65°C and a rotation speed of 150 r / min, a first coprecipitation reaction was carried out to produce the first nickel-cobalt-manganese hydroxide. During the first coprecipitation reaction, the nickel-cobalt-manganese mixed solution, aqueous ammonia solution, and sodium hydroxide solution were continuously supplied and discharged. During the reaction, the flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH of the first coprecipitation reaction system within the range of 11.50 to 11.70, and the ammonia concentration was controlled to fluctuate within the range of 4 to 4.5 g / L, thereby stabilizing the particle size. After the first coprecipitation reaction stabilized, the first nickel-cobalt-manganese hydroxide was obtained.

[0038] The first nickel-cobalt-manganese hydroxide was used as a seed crystal and placed in a reactor together with pure water, sodium hydroxide solution, and aqueous ammonia solution. The mixture was stirred uniformly at a constant temperature to obtain a second base solution with a pH of 10.50-10.80. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the aqueous ammonia solution was 21 wt%. For protection, an inert gas was introduced into the second base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution into the reactor containing the second base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 7% / h, the aqueous ammonia solution 0.20% / h, and the sodium hydroxide solution 2.59% / h. The first nickel-cobalt-manganese hydroxide was grown via a second coprecipitation reaction under stirring conditions of a constant temperature of 65°C and a rotational speed of 150 r / min. During the second coprecipitation reaction, the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution were continuously supplied and discharged. The flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH of the second coprecipitation reaction system within the range of 10.40-10.60, and the ammonia concentration was controlled to fluctuate within the range of 4-4.5 g / L. The particle size was maintained stable by continuously adding the first nickel-cobalt-manganese hydroxide. After the second coprecipitation reaction stabilized, the second nickel-cobalt-manganese hydroxide was obtained.

[0039] The second nickel cobalt manganese hydroxide was centrifuged, washed, dried and sieved to obtain a positive electrode material precursor sample 2.

[0040] [Example 3] The cathode material precursor sample 3 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 (OH)2 and was prepared by the following method:

[0041] Using sulfate solutions of nickel, cobalt, and manganese, a nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared in a molar ratio of Ni:Co:Mn = 94:5:1. A sodium hydroxide solution with a concentration of 5.5 mol / L was prepared as a precipitant, and an ammonia aqueous solution with a concentration of 5 mol / L was prepared as a complexing agent.

[0042] Sodium hydroxide solution, aqueous ammonia, and water were mixed and placed in a reactor, followed by uniform stirring under constant temperature conditions to obtain a first base solution with a pH of 11-11.60. The mass percent concentration of the sodium hydroxide solution was 32 wt%, and the mass percent concentration of the aqueous ammonia was 21 wt%. For protection, an inert gas was introduced into the first base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, aqueous ammonia, and sodium hydroxide solution into the reactor containing the first base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 4% / h, the aqueous ammonia solution 0.20% / h, and the sodium hydroxide solution 1.48% / h. The mother liquor was discharged through a concentrator during the reaction, under stirring conditions of a constant temperature of 65°C and a rotational speed of 150 r / min. The mother liquor discharge rate was the same as the total material supply rate. The first nickel cobalt manganese hydroxide was obtained through the first coprecipitation reaction.

[0043] The first nickel cobalt manganese hydroxide was centrifuged, washed, dried and sieved to obtain a positive electrode material precursor sample 3.

[0044] [Comparative Example 1] The cathode material precursor sample 4 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 (OH)2 and was prepared by the following method:

[0045] Using sulfate solutions of nickel, cobalt, and manganese, a nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared in a molar ratio of Ni:Co:Mn = 94:5:1. A sodium hydroxide solution with a concentration of 5.5 mol / L was prepared as a precipitant, and an ammonia aqueous solution with a concentration of 5 mol / L was prepared as a complexing agent.

[0046] Sodium hydroxide solution, aqueous ammonia, and water were mixed and placed in a reactor, followed by uniform stirring under constant temperature conditions to obtain a first base solution with a pH of 11.6-11.70. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the added aqueous ammonia was 21 wt%. For protection, an inert gas was introduced into the first base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, aqueous ammonia, and sodium hydroxide solution into the reactor containing the first base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 4% / h, the aqueous ammonia solution 0.15% / h, and the sodium hydroxide solution 1.48% / h. While stirring at a constant temperature of 65°C, a first coprecipitation reaction was carried out to produce the first nickel-cobalt-manganese hydroxide. During the first coprecipitation reaction, the nickel-cobalt-manganese mixed solution, aqueous ammonia solution, and sodium hydroxide solution were continuously supplied and discharged. The flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted during the reaction to maintain the pH of the first coprecipitation reaction system within the range of 11.70 to 11.80, and the ammonia concentration was varied within the range of 3 to 3.5 g / L, thereby stabilizing the particle size. After the first coprecipitation reaction, the first nickel-cobalt-manganese hydroxide was obtained.

[0047] First nickel-cobalt-manganese hydroxide was used as seed crystals and placed in a reactor together with water, sodium hydroxide solution, and aqueous ammonia solution. The mixture was stirred uniformly at a constant temperature to obtain a second base solution with a pH of 10.50-10.80. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the aqueous ammonia solution was 21 wt%. For protection, an inert gas was introduced into the second base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution into the reactor containing the second base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution, the aqueous ammonia solution, and the sodium hydroxide solution were 6% / h, 0.15% / h, and 2.22% / h, respectively. First nickel-cobalt-manganese hydroxide was grown via a second coprecipitation reaction under stirring conditions of a constant temperature of 65°C and a rotational speed of 150 r / min. During the second coprecipitation reaction, the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution were continuously supplied and discharged. The flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH of the second coprecipitation reaction system within the range of 10.20-10.40, and the ammonia concentration was controlled to fluctuate within the range of 2-2.5 g / L. The particle size was maintained stable by continuously adding the first nickel-cobalt-manganese hydroxide. After the second coprecipitation reaction stabilized, the second nickel-cobalt-manganese hydroxide was obtained. The second nickel cobalt manganese hydroxide was centrifuged, washed, dried and sieved to obtain a positive electrode material precursor sample 4.

[0048] Comparative Example 2 The cathode material precursor sample 5 has the chemical formula Ni 0.92 Co 0.07 Mn 0.01 (OH)2 and was prepared by the following method: Using sulfate solutions of nickel, cobalt, and manganese, a nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared in a molar ratio of Ni:Co:Mn=92:7:1. A sodium hydroxide solution with a concentration of 5.5 mol / L was prepared as a precipitant, and an ammonia aqueous solution with a concentration of 5 mol / L was prepared as a complexing agent. Sodium hydroxide solution, aqueous ammonia, and water were mixed and placed in a reactor. The mixture was stirred uniformly under constant temperature conditions to obtain a first base solution with a pH of 11.6-11.70. The mass percent concentration of the added sodium hydroxide solution was 32 wt%, and the mass percent concentration of the added aqueous ammonia was 21 wt%. For protection, an inert gas was introduced into the first base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, aqueous ammonia, and sodium hydroxide solution into the reactor containing the first base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 4% / h, the aqueous ammonia solution was 0.15% / h, and the sodium hydroxide solution was 1.48% / h. The mixture was stirred at a constant temperature of 65°C, and a first coprecipitation reaction was carried out to produce the first nickel-cobalt-manganese hydroxide. During the first coprecipitation reaction, the nickel-cobalt-manganese mixed solution, aqueous ammonia solution, and sodium hydroxide solution were continuously supplied and discharged. The flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted during the reaction to maintain the pH of the first coprecipitation reaction system within the range of 10.70-10.80, and the ammonia concentration was controlled to fluctuate within the range of 3-3.5 g / L, thereby stabilizing the particle size. After the first coprecipitation reaction stabilized, the first nickel-cobalt-manganese hydroxide was obtained.

[0049] First nickel-cobalt-manganese hydroxide was used as seed crystals and placed in a reactor together with water, sodium hydroxide solution, and aqueous ammonia solution. The mixture was stirred uniformly at a constant temperature to obtain a second base solution with a pH of 10.50-10.80. The mass percentage of the sodium hydroxide solution was 32 wt%, and the mass percentage of the aqueous ammonia solution was 21 wt%. For protection, an inert gas was introduced into the second base solution, and a magnetic circulation pump was used to introduce the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution into the reactor containing the second base solution at equal rates. In terms of the total volume of the reactor, the flow rates of the nickel-cobalt-manganese mixed solution were 8% / h, the aqueous ammonia solution 0.28% / h, and the sodium hydroxide solution 2.96% / h. First nickel-cobalt-manganese hydroxide was grown via a second coprecipitation reaction under stirring conditions of a constant temperature of 65°C and a rotation speed of 150 r / min. During the second coprecipitation reaction, the nickel-cobalt-manganese mixed solution, sodium hydroxide solution, and aqueous ammonia solution were continuously supplied and discharged. The flow rates of the sodium hydroxide solution and aqueous ammonia solution were finely adjusted to maintain the pH of the second coprecipitation reaction system within the range of 10.20-10.40, and the ammonia concentration was controlled to fluctuate within the range of 2-2.5 g / L. The particle size was maintained stable by continuously adding the first nickel-cobalt-manganese hydroxide. After the second coprecipitation reaction stabilized, the second nickel-cobalt-manganese hydroxide was obtained.

[0050] The second nickel cobalt manganese hydroxide was centrifuged, washed, dried and sieved to obtain a positive electrode material precursor sample 5.

[0051] [Example 4] The reaction conditions for the positive electrode material precursor sample 6 prepared in Example 4 were the same as those in Example 1, except that the flow rate of the nickel-cobalt-manganese mixed solution added to the second base solution was 9% / h and the flow rate of the ammonia aqueous solution was 0.15% / h.

[0052] [Example 5] The reaction conditions for the positive electrode material precursor sample 7 prepared in Example 5 were the same as those in Example 2, except that the flow rate of the nickel-cobalt-manganese mixed solution added to the second base solution was 5% / h and the flow rate of the ammonia aqueous solution was 0.25% / h.

[0053] [Example 6] The cathode material precursor sample 8 prepared in Example 6 has the chemical formula Ni 0.88 Co 0.04 Mn 0.08 (OH)2. A nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared using sulfate solutions of nickel, cobalt, and manganese, with a molar ratio of Ni:Co:Mn=88:4:8. The other reaction conditions were the same as in Example 1.

[0054] [Example 7] The cathode material precursor sample 9 prepared in Example 7 has the chemical formula Ni 0.92 Co 0.05 Mn 0.03 The base solution was (OH)2. A nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared using sulfate solutions of nickel, cobalt, and manganese, with a molar ratio of Ni:Co:Mn=92:5:3. The reaction conditions were the same as in Example 3, except that the pH of the first base solution was 11.3 to 11.90, the flow rate of the nickel-cobalt-manganese mixed solution added to the first base solution was 5% / h, the flow rate of the sodium hydroxide solution was 1.9% / h, and the reaction temperature was a constant 60°C.

[0055] [Example 8] The reaction conditions for the positive electrode material precursor sample 10 prepared in Example 8 were the same as those in Example 7, except that the pH of the first base solution was 11.4 to 11.90 and the flow rate of the nickel-cobalt-manganese mixed solution added to the first base solution was 4.5% / h.

[0056] [Example 9] The reaction conditions for the positive electrode material precursor sample 11 prepared in Example 9 were the same as those in Example 7, except that the pH of the first base solution was 11.0 to 11.50 and the flow rate of the nickel-cobalt-manganese mixed solution added to the first base solution was 5% / h.

[0057] [Example 10] The cathode material precursor sample 12 prepared in Example 10 has the chemical formula Ni 0.88 Co 0.04 Mn 0.08 (OH)2. A nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared using sulfate solutions of nickel, cobalt, and manganese, with a molar ratio of Ni:Co:Mn=88:4:8. The other reaction conditions were the same as in Comparative Example 1.

[0058] Comparative Example 3 The cathode material precursor sample 13 prepared in Comparative Example 3 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 The base solution was (OH)2. A nickel-cobalt-manganese mixed solution with a concentration of 2.0 mol / L was prepared using sulfate solutions of nickel, cobalt, and manganese, with a molar ratio of Ni:Co:Mn = 94:5:1. The reaction conditions were the same as in Example 3, except that the pH of the first base solution was 11.0 to 11.40, the flow rate of the nickel-cobalt-manganese mixed solution added to the first base solution was 3.9% / h, and the flow rate of the sodium hydroxide solution was 1.46% / h. Measurements and evaluations were carried out on the positive electrode material precursor samples 1 to 13 prepared in the above Examples 1 to 10 and Comparative Examples 1 to 3, and the data were summarized in Tables 1 and 2.

[0059] [Table 1]

[0060] Here, "span" in Table 1 represents the particle size distribution, where span = (D90-D10) / D50, "101 / 001" is the peak intensity ratio between I(101) and I(001) in the XRD pattern, "number of sheets" is the average number of sheets in the primary particles, and "sheet thickness" is the thickness of each sheet. To evaluate the porosity characteristics, in this disclosure, image analysis software (avizo) was used to analyze the CP photograph to measure the void area and total area of ​​the test region, and the porosity of the test region was calculated using the formula: void area / total area × 100%. The cross section of the entire secondary particle was selected as the test region to obtain the porosity of the entire secondary particle. Several (e.g., 3 to 5) secondary particles were randomly selected as test subjects and measured using the above method to obtain the porosity of each secondary particle. The arithmetic mean value of the porosities was then calculated to obtain the porosity of the precursor material.

[0061] [Table 2]

[0062] The cathode material precursor sample 1 prepared in Example 1 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 The sample was (OH)2 with a particle size distribution span of 1.361. The SEM images and XRD patterns are shown in Figures 1a-1c, respectively. As shown in the CP image, the secondary particles of the cathode material precursor sample 1 were spherical, consisting of multiple primary particles, which were radially distributed. The primary particles had a width of 94 nm and a length of 754 nm, with an aspect ratio (ratio of length to width) of 8.0. The width and length of the primary particles represent the average width and average length of the primary particles, respectively. The specific measurement method is shown in Figure 1a-1. Four primary particles shown in the SEM image were randomly selected, and the length and width of primary particles A1, A2, A3, and A4 were measured. That is, L A1 = 529 nm, L A2 = 994 nm, L A3 = 763 nm, L A4 = 730 nm, and the calculated average length of the primary particles is (LA1 +L A2 +L A3 +L A4 ) / 4=754 nm, and W A1 = 82 nm, W A2 = 100 nm, W A3 = 103 nm, W A4 = 91 nm, and the calculated average width of the primary particles is (W A1 +W A2 +W A3 +W A4 ) / 4 = 94 nm. XRD measurement revealed that I(101) / I(001) = 1.20, the thickness of each sheet was 7.4 nm, and the average number of sheets in the primary particles was 24. The thickness of each sheet was specifically measured using the following measurement method. Ten different primary particles were randomly selected from at least three SEM photographs, and the thicknesses T1, T2...T9, and T10 of the primary particles and the numbers N1, N2...N9, and N10 were measured, respectively. The thickness of the sheets was (T1 + T2 + ... + T9 + T10) / (N1 + N2 + ... + N9 + N10), and the average number of sheets was (N1 + N2 + ... + N9 + N10) / 10 (the thickness and sheet of one of the primary particles are shown in Figure 1b-1). As a result, the thickness of the sheets was 7.4 nm and the average number was 24.

[0063] The cathode material precursor sample 2 prepared in Example 2 has the chemical formula Ni 0.92 Co 0.07 Mn 0.01 The primary particles of the cathode material precursor sample 2 were 64.5 nm wide and 478 nm long, with an aspect ratio of 7.41. XRD measurements revealed that the I(101) / I(001) ratio was 1.21, the thickness of each sheet was 7.17 nm, and the average number of sheets per primary particle was 8. The cathode material precursor sample 3 prepared in Example 3 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01The primary particles of the cathode material precursor sample 3 were (OH)2 with a particle size distribution span of 0.621. The SEM image and XRD pattern are shown in Figures 3a and 3b, respectively. The primary particles of the cathode material precursor sample 3 had a width of 76.8 nm, a length of 437 nm, and an aspect ratio of 5.69. XRD measurements revealed that the I(101) / I(001) ratio was 1.30, the thickness of each sheet was 11.56 nm, and the average number of sheets in the primary particles was 6.64.

[0064] The cathode material precursor sample 4 prepared in Comparative Example 1 has the chemical formula Ni 0.94 Co 0.05 Mn 0.01 The particle size distribution was 1.311 (span = 1.311). SEM images and XRD patterns are shown in Figures 4a-4c. The primary particles had a width of 117 nm, a length of 870 nm, and an aspect ratio of 7.44. XRD measurements revealed that the I(101) / I(001) ratio was 1.25, the thickness of each sheet was 1.98 nm, and the average number of sheets per primary particle was 51.

[0065] The cathode material precursor sample 5 prepared in Comparative Example 2 has the chemical formula Ni 0.92 Co 0.07 Mn 0.01 The particle size distribution was 1.391 (span = 1.391). SEM and XRD images are shown in Figures 5a-5c. The primary particles had a width of 75.2 nm and a length of 671.5 nm, giving an aspect ratio of 8.93. XRD measurements revealed that the I(101) / I(001) ratio was 1.10, the thickness of each sheet was 3.27 nm, and the average number of sheets per primary particle was 23.

[0066] Comparing Comparative Example 1 with Example 1, the primary particles in cathode material precursor Sample 4 according to Comparative Example 1 were relatively small, with each sheet having a thickness of less than 5 nm, and the average number of sheets was relatively large, exceeding 30. The primary particles were larger than those in Example 1, with widths exceeding 110 nm and lengths exceeding 800 nm. Comparing Comparative Example 2 with Example 2, the primary particles in Sample 5 of the positive electrode material precursor according to Comparative Example 2 were relatively small, with each sheet having a thickness of less than 5 nm, which was much smaller than those in Example 2.

[0067] Comparing Comparative Example 1 with Example 3, the primary particles in cathode material precursor Sample 4 according to Comparative Example 1 were relatively small, with each sheet having a thickness of less than 5 nm, and the average number of sheets was relatively large, exceeding 30. The primary particles were larger than those in Example 3, with widths exceeding 110 nm and lengths exceeding 800 nm.

[0068] Each of the cathode material precursor samples 1 to 13 according to Examples 1 to 10 and Comparative Examples 1 to 3 was uniformly mixed with lithium hydroxide in a molar ratio of 1.05:1. The mixture was sintered in an air atmosphere using a box furnace at a sintering temperature of 730°C for a holding time of 10 hours. After cooling to room temperature, the mixture was crushed and sieved to obtain the corresponding cathode materials 1 to 13.

[0069] Electrochemical performance evaluation was performed using coin-type half cells. Each of the above positive electrode materials 1 to 13, conductive carbon black, and the binder PVDF (polyvinylidene fluoride) were made into a slurry in a mass ratio of 8:1:1, and this was applied to aluminum foil to produce a positive electrode plate. A metallic lithium plate was used as the negative electrode plate, and 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1) was used as the electrolyte. The battery case, positive electrode plate, negative electrode plate, separator, elastic piece, and gasket were assembled in a vacuum glove box to form a coin cell. Electrochemical performance evaluation was performed using the LAND evaluation system.

[0070] A charge / discharge test was carried out at room temperature under conditions of 3.0 to 4.3 V at 0.1 C (1 C = 210 mAh / g), and a test of 100 cycles at 1 C. The test results are shown in Tables 3 and 4 below.

[0071] [Table 3]

[0072] [Table 4]

[0073] As can be seen from the electrical performance data in Table 3, the batteries prepared using the positive electrode material precursors of Examples 1 to 5 and Examples 7 to 9 each had a higher initial charge capacity and a higher initial discharge capacity at 0.1 C than those of Comparative Examples 1 and 2, and all had an initial discharge capacity higher than 227 mAh / g. The cycle performance of each of Examples 1 to 10 was superior to that of Comparative Examples 1 and 2, reaching 88% or more.

[0074] Since the thickness of the sheets of Samples 4 and 5 according to Comparative Examples 1 and 2 was not within the range of 5 to 15 nm, the initial charge performance, initial discharge performance, and cycle performance of the samples according to Comparative Examples 1 and 2 were all inferior to those of Examples 1 to 3.

[0075] As can be seen from Tables 1-4 and Figures 1-7 above, the thickness of each primary particle sheet in the cathode material precursor samples 1-3 and 6-11 of Examples 1-9 was within the range of 5-15 nm, and the average number of sheets was within the range of 5-30. This resulted in stable primary particle strength, allowing the primary particles to maintain their integrity even under high temperature and high voltage conditions after preparation into battery cathodes. Consequently, the battery cycle performance was relatively excellent. The peak intensity ratios (101 / 001) of the samples in Examples 1-3 all exceeded 1.2, indicating that the sheets in the cathode material precursor samples 1-3 all grew preferentially along the (101) plane, providing relatively wide and short paths for lithium ion transport, contributing to lithium ion transport and improving battery capacity after preparation into battery cathodes. The relatively narrow (001) and (101) half-widths indicate good crystallinity of the samples, which can further contribute to the cycling performance of batteries prepared with the corresponding cathode materials.

[0076] Comparison between Comparative Example 1 and Example 1 shows that the cathode material precursor sample 4 prepared in Comparative Example 1 had a thickness of 1.98 nm (less than 5 nm), a number of 51 sheets, and a primary particle thickness of more than 110 nm. Both the thickness of each individual sheet and the average number of sheets were outside the appropriate range. As can be seen from the electrical performance test data shown in Table 2, the battery prepared using the cathode material corresponding to Sample 4 had a relatively low initial charge capacity and a relatively low initial discharge capacity at 0.1 C, and exhibited poor capacity performance after 100 cycles. Similarly, comparison between Comparative Example 2 and Example 2 shows that the thickness of each sheet in Sample 5 was 3.27 nm (outside the appropriate sheet thickness range), and the peak intensity ratio (101) / (001) was relatively small. As can be seen from the electrical performance test data shown in Table 2, the battery prepared using the cathode material corresponding to Sample 5 had a lower initial charge capacity and a relatively low initial discharge capacity at 0.1 C, and exhibited poor capacity performance after 100 cycles.

[0077] As described above, the cathode material precursors according to Examples 1 to 9 of the present disclosure had primary particle sheets with thicknesses ranging from 5 to 15 nm and an average number of sheets ranging from 5 to 30. Because the thickness and average number of primary particles were within appropriate ranges, they contributed to lithium ion transport and improved the capacity of batteries prepared using the corresponding cathode materials. By controlling the thickness of the primary particles to within the range of 30 to 110 nm, appropriate strength of the cathode material was ensured, and sufficient contact between the cathode material and the electrolyte was ensured, further contributing to improved capacity. The peak intensity ratios (101 / 001) were all greater than 1.2, indicating that the sheets grew preferentially along the (101) plane, shortening and widening the lithium ion transport path, increasing the lithium ion conductivity, and improving the capacity and cycle performance of the cathode material.

[0078] The primary particles of the cathode material precursor according to the present disclosure include multiple layers of sheets, each having a thickness of 5 to 15 nm and an average number of sheets in the primary particles of 5 to 30. Preferably, the average number of sheets is 5 to 30, and the thickness of each sheet is 5 to 12 nm. In the present disclosure, by setting the thickness and average number of sheets within the above ranges, the strength of the primary particles of the cathode material precursor is stabilized. After preparation into a battery cathode, the integrity of the primary particles is maintained even under high temperature and high voltage conditions, thereby ensuring the cycle performance of the battery. Sheets with an appropriate number and thickness range ensure an appropriate width of the primary particles, thereby reducing side reactions between the cathode material and the electrolyte and improving the safety of the prepared battery. Furthermore, sheets with an appropriate number and thickness range ensure the strength of the material and prevent the lithium ion transport pathway from becoming too narrow. This contributes to lithium ion transport and prevents a decrease in lithium ion conductivity. Therefore, the electric capacity and cycle performance of the cathode material prepared from the cathode material precursor are higher.

[0079] Although the above has shown and described embodiments of the present disclosure, the above embodiments are merely illustrative and are not intended to limit the present disclosure. Those skilled in the art may make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present disclosure.

[0080] Industrial Applicability The present disclosure provides a cathode material precursor, a preparation method thereof, a cathode material, and a lithium-ion battery. In the cathode material precursor, preparation method thereof, cathode material, and lithium-ion battery according to the present disclosure, the primary particles of the cathode material precursor comprise multilayered sheets, with an average number of sheets ranging from 5 to 30, and each sheet having a thickness ranging from 5 to 15 nm. The cathode material precursor and preparation method according to the present disclosure can solve the problem of reduced capacity and cycle performance in ternary lithium battery cathode materials, which is caused by difficulty in intercalating and deintercalating lithium ions and low lithium ion conductivity. By designing the structure of the cathode material precursor according to the present disclosure, the intercalation, intercalation, and diffusion of lithium ions into the cathode material are facilitated, significantly improving lithium ion conductivity and further improving the capacity and cycle performance of the cathode material. Furthermore, the cathode material precursor, the preparation method thereof, the cathode material, and the lithium ion battery according to the present disclosure are operable and can be used in various industrial applications, for example, the cathode material precursor, the preparation method thereof, the cathode material, and the lithium ion battery according to the present disclosure can be used in the technical field of lithium ion batteries.

Claims

1. A positive electrode material precursor, the primary particles of the positive electrode material precursor include a plurality of layers of sheets; The average number of the sheets is 5 to 30, and the thickness of each of the sheets is 5 to 15 nm. Positive electrode material precursor.

2. The average number of the sheets is 5 to 30, and each of the sheets has a thickness of 5 to 12 nm, preferably the average number of the sheets is 8 to 25, and each of the sheets has a thickness of 7 to 12 nm, preferably the average number of the sheets is 8 to 25, and each of the sheets has a thickness of 7 to 11.5 nm. The positive electrode material precursor of claim 1 .

3. the primary particles of the positive electrode material precursor are formed by stacking a plurality of the sheets, Preferably, the primary particles formed by laminating a plurality of the sheets have an elongated shape, Preferably, the particle width of the primary particles is 30 to 150 nm, the particle length of the primary particles is 400 to 800 nm, and the aspect ratio of the primary particles is 2.0 to 13.0, preferably 4.0 to 13.

0. The positive electrode material precursor of claim 1 .

4. The positive electrode material precursor has the chemical formula Ni ｘ Co ｙ M ｚ (OH) ２ where x+y+z=1, 0.7≦x<1, 0≦y≦0.3, 0<z≦0.3 are satisfied, and M is at least one selected from Mg, Sr, Ba, B, Al, Si, Mn, Ti, Zr, and W. The positive electrode material precursor of claim 1 .

5. In an XRD pattern of the positive electrode material precursor, the peak intensity ratio of I(101) to I(001) is 1.05 to 1.5, and / or the porosity of the positive electrode material precursor is 2% to 14%, preferably the porosity of the positive electrode material precursor is 3% to 12%, and / or the positive electrode material precursor has a D50 of 2 to 18 μm. The positive electrode material precursor of claim 1 .

6. In the XRD pattern of the positive electrode material precursor, the half width of the (001) plane is 0.40° to 0.65°, and the half width of the (101) plane is 0.45° to 0.60°. The positive electrode material precursor according to any one of claims 1 to 5.

7. 1. A method for preparing a cathode material precursor, comprising: The preparation method comprises: Preparing a metal salt solution, a precipitating agent, and a complexing agent; and mixing the metal salt solution, a precipitating agent, and a complexing agent to perform a co-precipitation reaction to obtain the positive electrode material precursor. Method for preparing a cathode material precursor.

8. The step of mixing the metal salt solution, the precipitant, and the complexing agent to perform a co-precipitation reaction to obtain the positive electrode material precursor specifically includes the steps of: mixing the precipitant, the complexing agent, and pure water to obtain a first base solution; and adding the metal salt solution, the complexing agent, and the precipitant to the first base solution to carry out a first co-precipitation reaction to obtain the positive electrode material precursor. The preparation method according to claim 7.

9. The step of mixing the metal salt solution, the precipitant, and the complexing agent to perform a co-precipitation reaction to obtain the positive electrode material precursor specifically includes the steps of: mixing the precipitating agent, the complexing agent, and pure water to obtain a first base solution, and adding the metal salt solution, the complexing agent, and the precipitating agent to the first base solution to perform a first co-precipitation reaction to obtain the first metal hydroxide; mixing the first metal hydroxide, pure water, the precipitating agent, and the complexing agent to obtain a second base solution, and adding the metal salt solution, the complexing agent, and the precipitating agent to the second base solution to perform a second co-precipitation reaction to obtain the positive electrode material precursor. The preparation method according to claim 7.

10. In the step of preparing a metal salt solution, a precipitating agent, and a complexing agent, the metal salt solution has a concentration of 1.0 to 2.0 mol / L, the precipitating agent includes a sodium hydroxide aqueous solution having a concentration of 5 to 12 mol / L, and the complexing agent includes an ammonia aqueous solution having a concentration of 1 to 10 mol / L; The flow rate of the metal salt solution added to the first base solution or the second base solution is 4.0% to 7.5% / h of the total volume of the reaction vessel, the pH value of the first base solution is 11 to 12, and the ammonia concentration of the reaction system is 2 to 5 g / L.

10. The preparation method according to claim 8 or 9.

11. The pH value of the second base solution is 10 to 11, and the ammonia concentration of the reaction system is 2 to 6 g / L, preferably 3 to 6 g / L.

10. The preparation method according to claim 9.

12. A positive electrode material, The positive electrode material is prepared from the positive electrode material precursor according to any one of claims 1 to 6. Positive electrode material.

13. A lithium-ion battery, The raw material of the lithium ion battery comprises the positive electrode material according to claim 12. Lithium-ion battery.

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