Preparation method of high-nickel ternary positive electrode material and lithium ion battery

Abstract

The invention relates to the technical field of battery materials, in particular to a preparation method of a high-nickel ternary positive electrode material and a lithium ion battery, and the preparation method comprises the following steps: under the protection of protective gas, mixing nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to prepare turbid liquid; carrying out ultrasonic precipitation treatment on the turbid liquid and drying to prepare a precursor; performing first calcining treatment on the precursor to prepare a first calcined material; mixing the first calcined material with a lithium source, and performing second calcining treatment to prepare the high-nickel ternary positive electrode material, the sum of the atomic mole numbers of nickel, cobalt and manganese in the turbid liquid is 100%, and the atomic mole percentage of nickel is 80% or above. According to the preparation method disclosed by the invention, by performing ultrasonic precipitation treatment on a high-concentration acetate system, atomic-scale uniform mixing of nickel, cobalt and manganese is promoted, and the structural stability of a precursor material is improved; grains are refined, precursor agglomeration is inhibited, the size uniformity of the precursor is improved, and the cycling stability and the capacity retention ratio of the battery are improved.

Description

Technical Field

[0001] This application relates to the field of battery materials technology, and in particular to the preparation method of high-nickel ternary cathode materials and lithium-ion batteries. Background Technology

[0002] In high-nickel ternary materials, the atomic-level uniform mixing of nickel, cobalt, and manganese is crucial. However, when using traditional co-precipitation processes with a high nickel and low cobalt-manganese ratio, component segregation is easily caused by differences in the precipitation rates of nickel, cobalt, and manganese ions, forming local nickel-rich or manganese-rich regions. This non-uniformity will deteriorate the structural stability of the material, exacerbate lattice stress and phase transitions during charge and discharge, and lead to accelerated capacity decay and decreased cycle performance.

[0003] Meanwhile, the preparation of high-nickel ternary precursors in a high-concentration acetate system also faces the problem of difficulty in controlling the precursor morphology. High-nickel precursors are prone to forming hard agglomerates or irregular growth, which reduces their sintering activity and the cycle stability, rate performance and capacity retention of the battery. Summary of the Invention

[0004] Based on this, this application provides a method for preparing high-nickel ternary cathode materials and a lithium-ion battery. By performing ultrasonic precipitation treatment on a high-concentration acetate system, the atomic-level uniform mixing of nickel, cobalt, and manganese is promoted, thereby improving the structural stability of the precursor material. At the same time, the grains are refined, the precursor agglomeration is suppressed, and the size uniformity of the precursor is improved, thereby improving the cycle stability, rate performance, and capacity retention of the battery.

[0005] The first aspect of this application provides a method for preparing a high-nickel ternary cathode material, comprising the following steps:

[0006] Under the protection of a protective gas, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate were mixed to prepare a suspension;

[0007] The suspension was subjected to ultrasonic precipitation and dried to prepare the precursor;

[0008] The precursor is subjected to a first calcination treatment to prepare the first calcined material;

[0009] The first calcined material is mixed with a lithium source and then subjected to a second calcination treatment to prepare a high-nickel ternary cathode material.

[0010] With the sum of the atomic moles of nickel, cobalt and manganese in the suspension being 100%, the atomic mole percentage of nickel is over 80%.

[0011] In some embodiments, the atomic molar ratio of nickel, cobalt, and manganese in the suspension is 8:1:1.

[0012] In some implementations, ultrasonic precipitation satisfies at least one of the following conditions:

[0013] (1) The ultrasonic frequency is 10kHz~50kHz;

[0014] (2) The ultrasonic power is 100W~1000W;

[0015] (3) The ultrasound time is 20 min to 80 min.

[0016] In some embodiments, the ultrasonic precipitation uses an ultrasonic frequency of 40 kHz, an ultrasonic power of 400 W, and an ultrasonic time of 40 min.

[0017] In some implementations, drying satisfies at least one of the following conditions:

[0018] (1) The drying temperature is 40℃~80℃;

[0019] (2) The drying time is 2h~12h.

[0020] In some embodiments, in the step of mixing the first calcined material with the lithium source, the ratio of the sum of the atomic moles of nickel, cobalt and manganese in the first calcined material to the atomic moles of lithium atoms in the lithium source is 1:(1.02~1.1).

[0021] In some embodiments, the lithium source includes one or more of lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate, and lithium acetate.

[0022] In some embodiments, the first calcination treatment satisfies at least one of the following conditions:

[0023] (1) The heating rate is 4℃ / min to 6℃ / min;

[0024] (2) The calcination temperature is 400℃~600℃;

[0025] (3) The calcination time is 3h~5h.

[0026] In some embodiments, the step of preparing high-nickel ternary cathode material by mixing the first calcined material with a lithium source and then performing a second calcination treatment includes: mixing the first calcined material with a lithium source, heating it to 650°C to 850°C at a heating rate of 4°C / min to 6°C / min and holding it at that temperature for 5h to 8h, and then cooling it to prepare high-nickel ternary cathode material.

[0027] The second aspect of this application provides a lithium-ion battery, including a high-nickel ternary cathode material prepared by the preparation method of the high-nickel ternary cathode material provided in the first aspect of this application.

[0028] Compared with traditional technologies, this application has the following advantages:

[0029] This application utilizes ultrasonic precipitation treatment on a high-concentration acetate system under protective gas to achieve highly atomic-level uniform mixing of nickel, cobalt, and manganese in the three acetate materials, thereby improving the structural stability of the high-nickel ternary cathode material. Simultaneously, ultrasonic energy is used to lower the nucleation barrier, inducing a large number of uniform nucleations. Furthermore, the cavitation microjets and shear forces provided by ultrasound prevent particle aggregation and break up the newly formed micro-aggregates to form small and uniform precursor materials, thereby improving the cycle stability, rate performance, and capacity retention of the battery. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram illustrating the preparation method of high-nickel ternary cathode material in some embodiments of this application.

[0032] Figure 2 This is a SEM (scanning electron microscope) image of the high-nickel ternary cathode material prepared in Example 1 of this application.

[0033] Figure 3 The image shows the XRD (X-ray diffraction) pattern of the high-nickel ternary cathode material prepared in Example 1 of this application.

[0034] Figure 4 This is a schematic diagram of the rate performance of the high-nickel ternary cathode materials prepared in Examples 1 to 3 of this application.

[0035] Figure 5 This is a schematic diagram of the cycle performance of the high-nickel ternary cathode materials prepared in Examples 1 to 3 of this application. Detailed Implementation

[0036] A detailed reference is now provided to embodiments of this application, one or more of which are described below. Each embodiment is provided for explanation and not for limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0037] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0038] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0039] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0040] In this article, when referring to units of data ranges, if a unit is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0041] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0042] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0043] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0044] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0045] like Figure 1As shown, the first aspect of this application provides a method for preparing a high-nickel ternary cathode material, comprising the following steps:

[0046] S1. Under the protection of a protective gas, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate are mixed to prepare a suspension.

[0047] S2. The suspension is subjected to ultrasonic precipitation and dried to prepare the precursor.

[0048] S3. The precursor is subjected to a first calcination treatment to prepare the first calcined material.

[0049] S4. After mixing the first calcined material with the lithium source, a second calcination treatment is carried out to prepare a high-nickel ternary cathode material.

[0050] With the sum of the atomic moles of nickel, cobalt and manganese in the suspension being 100%, the atomic mole percentage of nickel is over 80%.

[0051] This application utilizes ultrasonic precipitation treatment on a high-concentration acetate system under protective gas to achieve highly atomic-level uniform mixing of nickel, cobalt, and manganese in the three acetate materials, thereby improving the structural stability of the high-nickel ternary cathode material. Simultaneously, ultrasonic energy is used to lower the nucleation barrier, inducing a large number of uniform nucleations. Furthermore, the cavitation microjets and shear forces provided by ultrasound prevent particle aggregation and break up newly formed micro-aggregates to form small and uniform precursor materials, thereby improving the cycle stability and capacity retention of the battery.

[0052] The ultrasonic precipitation method used in this application has high production efficiency and controllability, is suitable for large-scale preparation, and helps to reduce production costs and improve production efficiency.

[0053] In the above-mentioned S1, by using a high-concentration metal salt solution for the reaction, the local collision frequency and mass transfer efficiency of the reactants can be effectively increased, thereby increasing the reaction rate. At the same time, the amount of solvent required per unit yield is reduced, the energy consumption and time of subsequent drying are reduced, and the production cost is lowered. Ultimately, a more concentrated and easier-to-handle precursor product is obtained, which provides convenience for subsequent processes.

[0054] Meanwhile, tetrahydrates of nickel acetate, cobalt acetate, and manganese acetate were chosen. These salts containing water of crystallization exhibit higher stability in air at room temperature, are less prone to hygroscopic agglomeration or weathering, and their solubility in water is generally higher than that of their corresponding anhydrous salts. This facilitates the rapid preparation of high-concentration, homogeneous suspensions, laying the foundation for the subsequent formation of precursors with highly uniform composition.

[0055] In some embodiments, the protective gas is an inert gas, such as argon or nitrogen. This inert atmosphere effectively prevents transition metal ions (especially divalent nickel, cobalt, and manganese ions) in the solution from being oxidized by air during preparation and ultrasonic treatment, thereby ensuring the uniformity and accuracy of the precursor components and valence states. Further, nitrogen is used as the protective gas.

[0056] In one specific embodiment, the atomic molar ratio of nickel, cobalt, and manganese in the suspension is 8:1:1.

[0057] In some embodiments, the ultrasonic frequency in the ultrasonic precipitation process is 10kHz to 50kHz, for example, 10kHz, 20kHz, 25kHz, 30kHz, 35kHz, 40kHz, 45kHz, 50kHz, and any value within the range of any two of the above values. Further, the ultrasonic frequency is 40kHz. By controlling the ultrasonic frequency within the range of 10kHz to 50kHz, appropriate cavitation intensity and shear force are provided to the reaction system to achieve effective micro-mixing and mass transfer; this avoids excessive cavitation and shear force due to excessively low ultrasonic frequencies, which could lead to excessive disturbance and affect particle growth; simultaneously, it avoids insufficient cavitation due to excessively high ultrasonic frequencies, which would make it difficult to effectively break the concentration gradient and inhibit aggregation, thereby affecting reaction uniformity and product dispersibility.

[0058] In some embodiments, the ultrasonic power in the ultrasonic precipitation process is 100W to 1000W, for example 100W, 300W, 500W, 700W, 800W, 1000W, and any value within the range of any two of the above values.

[0059] In some embodiments, the ultrasonic precipitation process takes place over a period of 20 to 80 minutes, for example, 20, 30, 35, 40, 45, 50, 60, or 80 minutes, or any value within any two of these ranges. More specifically, the ultrasonic time is 40 minutes. By controlling the ultrasonic precipitation process to 20 to 80 minutes, the time cost is reduced while ensuring complete reaction. This avoids incomplete reaction due to too short a time, and increased energy consumption and damage to the formed particles due to too long a time.

[0060] In one specific embodiment, the ultrasonic precipitation uses an ultrasonic frequency of 40 kHz, an ultrasonic power of 400 W, and an ultrasonic time of 40 min. By jointly controlling the ultrasonic frequency, ultrasonic power, and ultrasonic time, the time cost is reduced while ensuring more uniform atomic-level mixing of the reactants in the suspension, ensuring the formation of more uniform precursor substances, and avoiding the adverse effects caused by strong turbulence and violent bubbles.

[0061] In some embodiments, the drying temperature is 40°C to 80°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, and any value within the range of any two of the above values. By setting the drying temperature within this range, the risk of over-drying the sample is reduced, preventing problems such as cracking and deformation, reducing the possibility of thermal decomposition of the material, and preventing precursor decomposition or lattice distortion due to excessively high temperatures. Further, the drying temperature is 60°C.

[0062] In some embodiments, the drying time is 2 hours to 12 hours, for example, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, and any value within the range of any two of the above values. Further, the drying time is 6 hours.

[0063] In some implementations, a forced-air drying oven is used for drying. This makes it easier to control the precise temperature and ensures the stability and repeatability of the drying process.

[0064] In some embodiments, in the step of mixing the first calcined material with the lithium source, the ratio of the sum of the atomic moles of nickel, cobalt and manganese in the first calcined material to the atomic moles of lithium atoms in the lithium source is 1:(1.02~1.1).

[0065] In some embodiments, the lithium source includes one or more of lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate, and lithium acetate. Further, the lithium source is lithium carbonate (Li₂CO₃), which exhibits relatively stable performance at high temperatures, good processing properties, and is inexpensive compared to other lithium salts, offering a cost advantage.

[0066] In some embodiments, the heating rate in the first calcination treatment is 4°C / min to 6°C / min, for example, 4°C / min, 4.5°C / min, 5°C / min, 5.5°C / min, 6°C / min, and any value within the range of any two of the above values. Further, the heating rate is 5°C / min.

[0067] In some embodiments, the calcination temperature in the first calcination treatment is 400°C to 600°C, for example, 400°C, 450°C, 500°C, 550°C, or 600°C. Further, the calcination temperature is 500°C.

[0068] In some embodiments, the calcination time in the first calcination treatment is 3h to 5h, for example, 3h, 3.5h, 4h, 4.5h, or 5h. Further, the calcination time in the first calcination treatment is 4h.

[0069] In some embodiments, the step of preparing high-nickel ternary cathode material by mixing the first calcined material with a lithium source and then performing a second calcination treatment includes: mixing the first calcined material with a lithium source, heating it to 650°C to 850°C at a heating rate of 4°C / min to 6°C / min and holding it at that temperature for 5h to 8h, and then cooling it to prepare high-nickel ternary cathode material.

[0070] Understandably, the heating rate for the second calcination is 4℃ / min to 6℃ / min, for example, 4℃ / min, 4.5℃ / min, 5℃ / min, 5.5℃ / min, 6℃ / min, or any value within the range of any two of the above values. Further, the heating rate is 5℃ / min. By setting the heating rate to 4℃ / min to 6℃ / min, the lithium source and the first calcined material can be fully and uniformly mixed and contacted, thereby generating a high-nickel ternary cathode material with uniform composition and good crystallinity in the subsequent solid-state reaction.

[0071] The second calcination temperature is 650℃~850℃, for example, 650℃, 700℃, 750℃, 800℃, 850℃, and any value within the range of any two of the above values. Further, the calcination temperature is 800℃.

[0072] The second calcination time is 5 hours to 8 hours, for example, 5 hours, 6 hours, 7 hours, 8 hours, or any value within the range of any two of the above values. Further, the second calcination time is 5 hours to 8 hours.

[0073] The second aspect of this application provides a lithium-ion battery, including a high-nickel ternary cathode material prepared by the preparation method of the high-nickel ternary cathode material provided in the first aspect of this application.

[0074] Furthermore, this application provides the following specific embodiments and comparative examples to further illustrate the specific implementation of this application and its advantages.

[0075] Example 1

[0076] This embodiment provides a method for preparing a high-nickel ternary cathode material, specifically including the following steps:

[0077] (1) Under nitrogen protection, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate were mixed in an atomic molar ratio of 8:1:1 for transition metal elements n(Ni):n(Co):n(Mn) to obtain a suspension.

[0078] (2) The above suspension was placed in an ultrasonic bath and ultrasonically treated for 40 min at an ultrasonic frequency of 40 kHz and an ultrasonic power of 400 W. The resulting precipitate was then dried in a 60°C forced-air drying oven for 6 h to prepare the precursor.

[0079] (3) The above precursor is heated at 5℃ / min, and after being heated to 500℃, it is kept at 4h to prepare the first calcined material.

[0080] (4) Mix the nickel, cobalt and manganese atoms in the first calcined material at a ratio of 1:1.05 to the number of lithium atoms in the lithium source (Li2CO3). Heat the mixture at 5℃ / min until it reaches 800℃ and holds for 6 hours before cooling to prepare a high-nickel ternary cathode material.

[0081] Example 2

[0082] The preparation methods of this embodiment and Embodiment 1 are basically the same. The main difference is that the ultrasonic frequency in step (2) of this embodiment is 30kHz and the ultrasonic power is 350W.

[0083] Specifically: (2) The above suspension was placed in an ultrasonic bath and ultrasonically treated for 40 minutes at an ultrasonic frequency of 30 kHz and an ultrasonic power of 350 W. The resulting precipitate was then dried in a 60°C forced-air drying oven for 6 hours to prepare the precursor.

[0084] Example 3

[0085] The preparation methods of this embodiment and Embodiment 1 are basically the same. The main difference is that the ultrasonic frequency in step (2) of this embodiment is 10kHz and the ultrasonic power is 150W.

[0086] Specifically: (2) The above suspension was placed in an ultrasonic bath and ultrasonically treated for 40 minutes at an ultrasonic frequency of 10 kHz and an ultrasonic power of 100 W. The resulting precipitate was then dried in a 60°C forced-air drying oven for 6 hours to prepare the precursor.

[0087] Example 4

[0088] The preparation methods of this embodiment and Example 1 are basically the same. The main difference is that in this embodiment, the ultrasonic frequency in step (2) is 50kHz, the ultrasonic power is 1000W, and the ultrasonic treatment is 30min.

[0089] Specifically: (2) The above suspension was placed in an ultrasonic bath and ultrasonically treated for 30 minutes at an ultrasonic frequency of 50 kHz and an ultrasonic power of 1000 W. The resulting precipitate was then dried in a 60°C forced-air drying oven for 6 hours to prepare the precursor.

[0090] Example 5

[0091] The preparation methods of this embodiment and Example 1 are basically the same, the main difference being that the temperature is raised to 650°C in step (4) of this embodiment.

[0092] Specifically: (4) Mix the first calcined material with the sum of the atomic moles of nickel, cobalt and manganese and the number of lithium atoms in the lithium source (Li2CO3) at a ratio of 1:1.05, heat at 5℃ / min, heat to 650℃ and keep at 6h and then cool to prepare a high-nickel ternary cathode material.

[0093] Example 6

[0094] The preparation methods of this embodiment and Example 1 are basically the same, the main difference being that the temperature is raised to 700°C in step (4) of this embodiment.

[0095] Specifically: (4) Mix the materials according to the ratio of the sum of the atomic moles of nickel, cobalt and manganese in the first calcined material to the atomic moles of lithium atoms in the lithium source (Li2CO3) at 1:1.05, heat at 5℃ / min, heat to 700℃ and keep at 700℃ for 6h and then cool to prepare a high-nickel ternary cathode material.

[0096] Example 7

[0097] The preparation methods of this embodiment and Example 1 are basically the same, the main difference being that the temperature is raised to 850°C in step (4) of this embodiment.

[0098] Specifically: (4) Mix the materials according to the ratio of the sum of the atomic moles of nickel, cobalt and manganese in the first calcined material to the atomic moles of lithium atoms in the lithium source (Li2CO3) at 1:1.05, heat at 5℃ / min, heat to 850℃ and keep at 6h and then cool to prepare high-nickel ternary cathode material.

[0099] Comparative Example 1

[0100] (1) Preparation of solution:

[0101] Metal salt solution: Accurately weigh nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate according to the metal molar ratio of nickel, cobalt and manganese 8:1:1, and dissolve them together in deionized water to prepare a homogeneous mixed metal salt solution with a total metal ion concentration of 0.5 mol / L.

[0102] Precipitating agent solution: Prepare a 2.0 mol / L sodium hydroxide solution as a precipitating agent.

[0103] Complexing agent solution: Prepare an ammonia solution with a concentration of 0.5 mol / L as the complexing agent.

[0104] (2) Coprecipitation reaction: A certain amount of deionized water was first added to a reaction vessel equipped with a mechanical stirrer, a constant temperature water bath and a pH meter as the base liquid, and an appropriate amount of ammonia solution was added to maintain the ammonia concentration in the base liquid at 0.1 mol / L. Under the protection of nitrogen atmosphere, the base liquid was heated to 60°C and kept at a constant temperature.

[0105] Turn on the mechanical stirrer and set the speed to 500 rpm. Simultaneously and uniformly pump the metal salt mixed solution and the precipitant (NaOH) solution prepared in step (1) into the reactor. By controlling the flow rates of the two liquids, the pH value of the reaction system is precisely stabilized at 11.0 ± 0.1.

[0106] (3) Aging, separation and drying: After the feeding is completed, maintain the temperature and stir, and continue aging for 6 hours. After the reaction is completed, filter the obtained slurry and wash the filter cake repeatedly with deionized water to remove impurities such as sodium ions and ammonium ions. Place the washed filter cake in a forced-air drying oven and dry it at 100℃ for 12 hours to obtain high-nickel ternary hydroxide precursor powder.

[0107] (4) Calcination to prepare cathode material: The dried high-nickel ternary hydroxide precursor powder and lithium carbonate (Li2CO3) are uniformly mixed at a molar ratio of transition metal (total molar number of Ni, Co, Mn) to lithium of 1:1.05 to prepare a mixture.

[0108] The mixture was placed in a muffle furnace and calcined in two steps under an oxygen atmosphere: first, the temperature was increased to 500℃ at a rate of 5℃ / min and held for 5 h; then, the temperature was increased to 750℃ at a rate of 5℃ / min and held for 12 h. After calcination, the mixture was allowed to cool naturally to room temperature, ground, and sieved to prepare a high-nickel ternary cathode material.

[0109] Test case

[0110] (1) The high-nickel ternary cathode material prepared in Example 1 was subjected to SEM (scanning electron microscopy) testing, and the test results are as follows: Figure 2 As shown.

[0111] (2) The high-nickel ternary cathode material prepared in Example 1 was subjected to XRD (X-ray diffraction) testing. The test results are as follows: Figure 3 As shown.

[0112] (3) The high-nickel ternary cathode materials prepared in the above examples and comparative examples are used as cathode materials to prepare lithium-ion batteries. The specific process is as follows:

[0113] The high-nickel ternary cathode materials prepared in the above examples and comparative examples were used as cathode active materials. The cathode materials, binder PVDF, and conductive agent Super-P were weighed at a mass ratio of 8:1:1 and placed in a 10mL beaker. After mixing evenly, an appropriate amount of NMP (N-methylpyrrolidone) was added dropwise and stirred into a uniform slurry. The slurry was then coated onto dry aluminum foil using a scraper (150mm). The foil was first dried in a forced-air drying oven at 80℃ for 8 hours, and then transferred to a vacuum drying oven at 120℃ for 12 hours. The completely dried electrode was then shaped into 12mm diameter circular cathode sheets using a stamping machine and weighed and transferred to a glove box for later use.

[0114] Using the prepared positive electrode as the positive electrode and metallic lithium as the negative electrode, 1 mol·L -1 LiPF6 was dissolved in a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio = 1:1) to form the electrolyte. A Celgard 2400 polypropylene microporous membrane was used as the separator. All materials were placed in a glove box filled with high-purity argon (O2 < 0.1 ppm, H2O < 0.1 ppm) and assembled into a CR2032 coin cell, which was then sealed using a sealing machine. Finally, the assembled CR2032 coin cells were allowed to stand at room temperature for 12 hours for activation before use.

[0115] (4) The initial constant current charge-discharge capacity and the discharge capacity after 100 cycles of the CR2032 coin cells prepared from the high-nickel ternary cathode materials provided in the examples and comparative examples were tested respectively, and the capacity retention rate was calculated. The results are shown in Table 1 below. The test voltage range was 3.0V-5.0V (vs. Li + / Li), with a multiplier of 1C.

[0116] Table 1

[0117]

[0118] (5) The CR2032 coin cells prepared from the high-nickel ternary cathode materials provided in the examples and comparative examples were cycled 5 times at rates of 0.1C, 0.2C, 0.5C, 1C, 2C and 0.1C respectively, and the rate performance of the lithium-ion batteries was measured. The results are shown in Table 2 below.

[0119] Table 2

[0120]

[0121] like Figure 4 As shown, Figure 4 This is a schematic diagram of the rate performance of the high-nickel ternary cathode materials prepared in Examples 1 to 3 of this application.

[0122] like Figure 5 As shown, Figure 5 This is a schematic diagram of the cycle performance of the high-nickel ternary cathode materials prepared in Examples 1 to 3 of this application.

[0123] The comparison shows that, compared with the comparative example, the high-nickel ternary cathode material prepared by the preparation method provided in this application produces lithium-ion batteries with the best overall electrochemical performance, and is significantly superior to the comparative example in terms of high-rate discharge capability, reversible capacity and structural stability.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A preparation method of a high-nickel ternary positive electrode material, characterized in that, Includes the following steps: Under the protection of a protective gas, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate were mixed to prepare a suspension; The suspension was subjected to ultrasonic precipitation and dried to prepare a precursor; The precursor is subjected to a first calcination treatment to prepare a first calcined material; The first calcined material is mixed with a lithium source and then subjected to a second calcination treatment to prepare the high-nickel ternary cathode material. With the sum of the atomic moles of nickel, cobalt and manganese in the suspension being 100%, the atomic mole percentage of nickel is more than 80%.

2. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that, In the suspension, the atomic molar ratio of nickel, cobalt, and manganese is 8:1:

1.

3. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that, The ultrasonic precipitation satisfies at least one of the following conditions: (1) The ultrasonic frequency is 10kHz~50kHz; (2) The ultrasonic power is 100W~1000W; (3) The ultrasound time is 20 min to 80 min.

4. The method for preparing the high-nickel ternary cathode material according to claim 3, characterized in that, The ultrasonic precipitation process uses an ultrasonic frequency of 40kHz, an ultrasonic power of 400W, and an ultrasonic time of 40min.

5. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that, The drying process satisfies at least one of the following conditions: (1) The drying temperature is 40℃~80℃; (2) The drying time is 2h~12h.

6. The method for preparing the high-nickel ternary cathode material according to claim 1, characterized in that, In the step of mixing the first calcined material with the lithium source, the ratio of the sum of the atomic moles of nickel, cobalt and manganese in the first calcined material to the atomic moles of lithium atoms in the lithium source is 1:(1.02~1.1).

7. The method for preparing the high-nickel ternary cathode material according to claim 6, characterized in that, The lithium source includes one or more of lithium carbonate, lithium hydroxide, lithium nitrate, lithium oxalate, and lithium acetate.

8. The method for preparing the high-nickel ternary cathode material according to any one of claims 1-6, characterized in that, The first calcination treatment satisfies at least one of the following conditions: (1) The heating rate is 4℃ / min to 6℃ / min; (2) The calcination temperature is 400℃~600℃; (3) The calcination time is 3h~5h.

9. The method for preparing the high-nickel ternary cathode material according to any one of claims 1-6, characterized in that, The steps for preparing the high-nickel ternary cathode material include: mixing the first calcined material with a lithium source and then subjecting it to a second calcination treatment; mixing the first calcined material with a lithium source and then heating it to 650°C to 850°C at a heating rate of 4°C / min to 6°C / min and holding it at that temperature for 5 to 8 hours before cooling it to prepare the high-nickel ternary cathode material.

10. A lithium-ion battery, characterized in that, The high-nickel ternary cathode material prepared by the preparation method of the high-nickel ternary cathode material as described in any one of claims 1-9 includes the high-nickel ternary cathode material.

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