High-voltage ternary positive electrode material and preparation method and application thereof

Abstract

The present application relates to the field of positive electrode material preparation, and specifically to a high-voltage ternary positive electrode material, and a preparation method and an application thereof. The preparation method of the high-voltage ternary positive electrode material comprises: mixing a nickel-cobalt-manganese hydroxide precursor with a lithium source, and calcining same to obtain a high-voltage positive electrode material intermediate; mixing the high-voltage positive electrode material intermediate with a cobalt element additive and a lithium element additive, and calcining same to obtain the high-voltage ternary positive electrode material, wherein based on the weight of the high-voltage positive electrode material intermediate, the cobalt element doping amount in the cobalt element additive is 2000-10000 ppm, and the lithium element doping amount in the lithium element additive is 500-2000 ppm. The preparation method of the high-voltage ternary positive electrode material of the present application can improve the stability of the ternary positive electrode material, reduce the surface alkali of the ternary positive electrode material, and also increase the capacity under high voltage of a lithium-ion battery formed.

Description

A high-voltage ternary cathode material and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on June 25, 2023, with application number 202310755933.0 and application name “A high-voltage ternary positive electrode material, its preparation method and application”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of lithium battery positive electrode materials, and specifically to a high-voltage ternary positive electrode material and its preparation method and application. Background Art

[0004] Lithium-ion batteries are widely used in various consumer electronics and power battery fields due to their advantages such as high operating voltage, high specific energy density, long cycle life, and low environmental pollution. The performance of lithium-ion batteries is closely related to the properties of the electrode materials used. Developing high-energy-density, lightweight secondary batteries to reduce size and weight, and extend battery life is an urgent need for the industry.

[0005] Currently, the primary approach to improving the energy density of lithium-ion batteries is to increase the charge cutoff voltage. Traditional cathode materials, primarily based on lithium cobalt oxide (LCO), offer a wide discharge window and excellent cycling characteristics, but they cannot meet the demands for high capacity, high energy density, and safety. Furthermore, due to the high cobalt content in LCO, lithium-ion batteries using LCO as cathodes are environmentally polluting, and increasing the charge cutoff voltage of LCO can easily cause the structure of LCO to collapse. In recent years, ternary cathode materials have emerged, combining the characteristics of lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide (LMO) cathode materials. These materials offer a unique combination of structure and performance, and with high capacities exceeding 150 mAh / g, excellent cycling performance, a simple synthesis process, and environmental friendliness, they have become one of the most promising cathode materials for increasing charge cutoff voltage. Increasing the Ni content in ternary materials can effectively increase battery energy density, but increased Ni content can alter the layered structure.

[0006] Currently, high voltage is generally considered to be a full-electric test voltage of 4.35V or above. The high voltage range for ternary cathode materials is usually 4.35V-4.6V. The commonly used preparation method at this stage is to add elements to the material surface. Commonly used elements include: W, Y, Zr, Al, B, Sr, Ti, Mg, Co, etc. The Co element can effectively inhibit the Ni-Li mixing phenomenon in the material, improve the material's stability, and coat the surface of the material to resist electrolyte erosion and maintain the material's cycling performance.

[0007] For example, the prior art discloses a method for preparing a core-shell type high voltage single crystal lithium nickel cobalt manganese oxide positive electrode material. The patent selects to coat the surface of the material with Co element as a coating layer to resist electrolyte corrosion. However, in this method, the Co element reacts with the free Li in the material during the sintering process. + reaction, affecting the discharge capacity of the material.

[0008] Summary of the Invention

[0009] Therefore, the technical problem to be solved by this application is to overcome the defect in the prior art that the additives of the high-voltage ternary positive electrode material react with the lithium element in the ternary positive electrode material, affecting the discharge capacity of the lithium-ion battery, thereby providing a high-voltage ternary positive electrode material and its preparation method and application.

[0010] The present application provides a method for preparing a high-voltage ternary positive electrode material, comprising: S1, mixing a nickel-cobalt-manganese hydroxide precursor with a lithium source, and calcining the mixture to obtain a high-voltage positive electrode material intermediate; S2, mixing the high-voltage positive electrode material intermediate with a cobalt element additive and a lithium element additive, and calcining the mixture to obtain a high-voltage ternary positive electrode material, wherein the cobalt element doping amount in the cobalt element additive is 2000-10000 ppm, and the lithium element doping amount in the lithium element additive is 500-2000 ppm.

[0011] The lithium element doping amount in the lithium element additive is 800 ppm, and the cobalt element doping amount in the cobalt element additive is 8000 ppm.

[0012] The lithium element additive is at least one of lithium hydroxide and lithium carbonate; and / or the cobalt element additive is at least one of cobaltous oxide, cobaltous hydroxide, cobaltous carbonate and cobalt trioxide.

[0013] The calcination temperature in step S2 is 650-950° C., the heating rate is 2-5° C. / min, and the calcination time is 4-6 h.

[0014] The calcination in step S1 includes pre-calcining the mixture of nickel cobalt manganese hydroxide precursor and lithium salt in an oxidizing atmosphere at a temperature of 650-850°C at a heating rate of 2-5°C / min for 4-6 hours, and then calcining the mixture at a temperature of 800-950°C at a heating rate of 2-5°C / min for 8-12 hours.

[0015] The composition of the nickel-cobalt-manganese hydroxide precursor in step S1 is Ni x Co y Mn 1-x-y (OH)2, where 0.5<x≤1, 0<y≤0.5;

[0016] And / or, the nickel-cobalt-manganese hydroxide precursor has a specific surface area of ​​8-20 m2 / g;

[0017] And / or, the nickel-cobalt-manganese hydroxide precursor has a tap density of 1-2 g / cm 3 ;

[0018] And / or, the median particle size D50 of the nickel-cobalt-manganese hydroxide precursor is 3-7 μm.

[0019] In step S1, the lithium source is at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

[0020] In step S1, the molar ratio of the total moles of nickel, cobalt and manganese elements in the nickel-cobalt-manganese hydroxide precursor to the lithium element in the lithium salt is 1:0.9-1.2.

[0021] The present application provides a method for preparing a high-voltage ternary positive electrode material and the application of the high-voltage ternary positive electrode material in lithium-ion batteries.

[0022] The technical solution of this application has the following advantages:

[0023] 1. The preparation method of the high-voltage ternary positive electrode material provided in the present application comprises: mixing a nickel-cobalt-manganese hydroxide precursor with a lithium salt, and calcining the mixture to obtain a high-voltage positive electrode material intermediate; mixing the high-voltage positive electrode material intermediate with a cobalt element additive and a lithium element additive, and calcining the mixture to obtain a high-voltage ternary positive electrode material, wherein, based on the weight of the high-voltage positive electrode material intermediate, the cobalt element doping amount in the cobalt element additive is 2000-10000ppm, and the lithium element doping amount in the lithium element additive is 500-2000ppm. The present application adopts a calcination method, using a higher temperature to sinter the Co element into the material structure, so that the Co element is combined with the material rather than simply existing in the form of a coating layer. During the sintering process of the material, the Co element tends to react with the free Li in the material. + React to form a stable structure, in which a small amount of Co element reacts with the residual Li on the surface of the material + Reaction with internal Li + The reaction generates a transition metal layer to protect the material, reducing the Ni + -Li + The phenomenon of mixed arrangement improves the cycle retention rate of the material, but the Co element and part of the Li + The reaction will absorb some free Li + , thus affecting the discharge capacity of the material. Therefore, the present application adds additional lithium elements so that during the high-temperature calcination process, the cobalt element reacts preferentially with the lithium in the added lithium-containing additive, thereby reducing the reaction of the cobalt element with the original lithium element in the ternary positive electrode material during the calcination of the ternary positive electrode material, thereby alleviating the problem of decreased discharge capacity of the lithium-ion battery;

[0024] At the same time, by adding an appropriate amount of lithium element, the lithium ions in the ternary positive electrode material react with the cobalt element to form a more stable LiCoO3, which is organically combined with the ternary positive electrode material, can resist the erosion of the electrolyte and achieve the effect of resisting high-voltage electrolyte.

[0025] 2. The preparation method of the high-voltage ternary positive electrode material provided in the present application comprises the following steps: a high-voltage ternary positive electrode material intermediate is combined with a cobalt element additive and a lithium element additive, and the calcination temperature is 650-950°C, the heating rate is 2-5°C / min, and the calcination time is 4-6h. The present application limits the calcination conditions for forming a high-voltage ternary positive electrode material by incorporating the cobalt element additive and the lithium element additive into the high-voltage ternary positive electrode material intermediate, thereby achieving deep incorporation of the cobalt element and the lithium element into the high-voltage ternary positive electrode intermediate, thereby forming a high-voltage ternary positive electrode material with a more stable structure. On the premise of reducing the surface alkali of the high-voltage ternary positive electrode material, the mixing of Ni-Li in the lithium battery formed by the high-voltage ternary positive electrode material during the charge and discharge process is effectively suppressed, thereby improving the corrosion resistance of the high-voltage ternary positive electrode material to the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] FIG1 is a flow chart of a method for preparing a high-voltage ternary positive electrode material in Example 1 of the present application. DETAILED DESCRIPTION

[0028] The following examples are provided to further better understand the present application, but are not limited to the best implementation mode described herein, and do not limit the content and protection scope of the present application. Any product identical or similar to the present application obtained by anyone under the inspiration of the present application or by combining the features of the present application with other prior arts shall fall within the scope of protection of the present application.

[0029] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0030] Example 1

[0031] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0032] According to the molar ratio of the total molar number of nickel, manganese and cobalt in the nickel-cobalt-manganese hydroxide precursor to the lithium element of 1:1.06, weigh Ni 0.6 Co 0.1 Mn 0.3 (OH)2 precursor and lithium carbonate, use high speed mixer to mix Ni 0.6 Co 0.1 Mn 0.3 The (OH)2 precursor is mixed evenly with lithium carbonate to form a first mixed powder, wherein Ni 0.6 Co 0.1 Mn 0.3 The specific surface area of ​​the (OH)2 precursor is 11m 2 / g, and the tap density is 1.83g / cm 3 , the median particle size D50 is 3.8 μm;

[0033] The first mixed powder was placed in a box furnace, with air as the oxidizing atmosphere and an atmosphere flow rate of 10 L / min. The temperature in the box furnace was raised to 800° C. at a heating rate of 2° C. / min, and the mixed powder was pre-calcined for 5 hours. The temperature in the box furnace was raised to 940° C. at a heating rate of 2° C. / min, and the pre-calcined mixed powder was high-temperature calcined for 10 hours. The mixture was naturally cooled to room temperature and pulverized to obtain a high-voltage positive electrode material intermediate.

[0034] The high-voltage intermediate was sieved with a filter mesh with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. Co(OH)2 and LiOH were evenly mixed using a high-speed mixer according to the addition amount of Co element being 8000 ppm and the addition amount of Li element being 800 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min, and the powder was calcined for 5 hours. After natural cooling, the powder was sieved to obtain a high-voltage ternary positive electrode material.

[0035] Example 2

[0036] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0037] According to the molar ratio of the total molar number of nickel, manganese and cobalt in the nickel-cobalt-manganese hydroxide precursor to the lithium element of 1:0.9, weigh Ni 0.7 Co 0.1 Mn 0.2 (OH)2 precursor and lithium hydroxide, using a high-speed mixer to mix Ni 0.7 Co 0.1 Mn 0.2 The (OH)2 precursor is mixed evenly with lithium hydroxide to form a first mixed powder, wherein Ni 0.7 Co 0.1 Mn 0.2The specific surface area of ​​the (OH)2 precursor is 8m 2 / g, tap density is 1g / cm 3 , the median particle size D50 is 5.5 μm;

[0038] The first mixed powder was placed in a box furnace, with oxygen as the oxidizing atmosphere and an atmosphere flow rate of 10 L / min. The temperature in the box furnace was raised to 650°C at a heating rate of 5°C / min, and the mixed powder was pre-calcined for 4 hours. The temperature in the box furnace was raised to 900°C at a heating rate of 2°C / min, and the pre-calcined mixed powder was high-temperature calcined for 8 hours. The mixture was naturally cooled to room temperature and pulverized to obtain a high-voltage positive electrode material intermediate.

[0039] The high-voltage intermediate was sieved with a filter with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. CoO and LiOH were evenly mixed using a high-pressure mixer according to the addition amount of Co element being 2000 ppm and the addition amount of Li element being 1000 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. Under an air atmosphere, the temperature of the box furnace was raised to 950°C at a heating rate of 5°C / min, and the mixture was calcined for 4 hours. After natural cooling, the mixture was sieved to obtain a high-voltage ternary positive electrode material.

[0040] Example 3

[0041] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0042] According to the molar ratio of the total molar number of nickel, manganese and cobalt in the nickel-cobalt-manganese hydroxide precursor to the lithium element of 1:1.2, weigh Ni 0.8 Co 0.1 Mn 0.1 (OH)2 precursor and lithium acetate, use high-speed mixer to mix Ni 0.8 Co 0.1 Mn 0.1 The (OH)2 precursor is mixed evenly with lithium acetate to form a first mixed powder, wherein Ni 0.8 Co 0.1 Mn 0.1 The specific surface area of ​​the (OH)2 precursor is 20m 2 / g, tap density is 2g / cm 3 , the median particle size D50 is 3 μm;

[0043] The first mixed powder was placed in a box furnace, with air as the oxidizing atmosphere and an atmosphere flow rate of 10 L / min. The temperature in the box furnace was raised to 650°C at a heating rate of 3°C / min, and the mixed powder was pre-calcined for 6 hours. The temperature in the box furnace was raised to 800°C at a heating rate of 4°C / min, and the pre-calcined mixed powder was high-temperature calcined for 12 hours. The mixture was naturally cooled to room temperature and pulverized to obtain a high-voltage positive electrode material intermediate.

[0044] The high-voltage intermediate was sieved with a filter with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. Co3O4 and Li2CO3 were evenly mixed using a high-pressure mixer according to the addition amount of Co element being 4000 ppm and the addition amount of Li element being 2000 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 650°C at a heating rate of 4°C / min, and the powder was calcined for 6 hours. After natural cooling, the powder was sieved to obtain a high-voltage ternary positive electrode material.

[0045] Example 4

[0046] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0047] According to the molar ratio of the total molar number of nickel, manganese and cobalt in the nickel-cobalt-manganese hydroxide precursor to the lithium element of 1:1.1, weigh Ni 0.6 Co 0.3 Mn 0.1 (OH)2 precursor and lithium carbonate, use high speed mixer to mix Ni 0.6 Co 0.3 Mn 0.1 The (OH)2 precursor is mixed evenly with lithium carbonate to form a first mixed powder, wherein Ni 0.6 Co 0.3 Mn 0.1 The specific surface area of ​​the (OH)2 precursor is 10m 2 / g, tap density is 1.5g / cm 3 , the median particle size D50 is 7 μm;

[0048] The first mixed powder was placed in a box furnace, with oxygen as the oxidizing atmosphere and an atmosphere flow rate of 10 L / min. The temperature in the box furnace was raised to 850° C. at a heating rate of 4° C. / min, and the mixed powder was pre-calcined for 5 hours. The temperature in the box furnace was raised to 850° C. at a heating rate of 2° C. / min, and the pre-calcined mixed powder was high-temperature calcined for 9 hours. The mixture was naturally cooled to room temperature and pulverized to obtain a high-voltage positive electrode material intermediate.

[0049] The high-voltage intermediate was sieved with a filter mesh with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. CoCO3 and Li2CO3 were evenly mixed using a high-pressure mixer according to the addition amount of Co element of 10000 ppm and the addition amount of Li element of 4000 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 750°C at a heating rate of 3°C / min, and the powder was calcined for 5.5 hours. After natural cooling, the powder was sieved to obtain a high-voltage ternary positive electrode material.

[0050] Example 5

[0051] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0052] The preparation method of the high voltage positive electrode material intermediate is the same as that in Example 1 of the present application;

[0053] The high-voltage intermediate was sieved with a filter mesh with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. Co(OH)2 and LiOH were evenly mixed using a high-speed mixer according to the addition amount of Co element being 10,000 ppm and the addition amount of Li element being 1,500 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min, and the powder was calcined for 5 hours. After natural cooling, the powder was sieved to obtain a high-voltage ternary positive electrode material.

[0054] Example 6

[0055] This embodiment provides a method for preparing a high-voltage ternary cathode material. The specific steps and parameters are as follows:

[0056] The preparation method of the high voltage positive electrode material intermediate is the same as that in Example 1 of the present application;

[0057] The high-voltage intermediate was sieved with a filter mesh with a pore size of 45 μm, and 1 kg of the sieved high-voltage intermediate was weighed. Co(OH)2 and LiOH were evenly mixed using a high-speed mixer according to the addition amount of Co element being 4000 ppm and the addition amount of Li element being 500 ppm to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min, and the mixture was calcined for 5 hours. After natural cooling, the mixture was sieved to obtain a high-voltage ternary positive electrode material.

[0058] Comparative Example 1

[0059] This comparative example provides a method for preparing a high-voltage positive electrode material, and the specific steps and parameters are as follows:

[0060] The preparation method of the high voltage positive electrode material intermediate is the same as that in Example 1 of the present application;

[0061] The high-voltage intermediate was sieved with a filter with a pore size of 45 μm, 1 kg of the sieved high-voltage intermediate was weighed, and Co(OH)2 was added in an amount of 8000 ppm of Co element. The high-voltage intermediate and cobalt hydroxide were evenly mixed using a high-speed mixer to form a second mixed powder. The second mixed powder was put into a box furnace. In an air atmosphere, the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min, and the powder was calcined for 5 hours. After natural cooling, the powder was sieved to obtain a high-voltage ternary positive electrode material.

[0062] Comparative Example 2

[0063] This comparative example provides a method for preparing a high-voltage positive electrode material, and the specific steps and parameters are as follows:

[0064] The second mixed powder was prepared in the same manner as in Comparative Example 1;

[0065] The second mixed powder was put into a box furnace, and the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min under an air atmosphere. The mixture was calcined for 5 hours, and naturally cooled and sieved to obtain the fired second mixture. LiOH was added with the fired second mixture in an amount of 800ppm of Li element, and mixed evenly with a high mixer to form a third mixed powder. The third mixed powder was put into a box furnace, and the temperature of the box furnace was raised to 850°C at a heating rate of 2°C / min under an air atmosphere. The mixture was calcined for 5 hours, and naturally cooled and sieved to obtain the high-voltage ternary positive electrode material.

[0066] Experimental example

[0067] The surface alkali content of the high-voltage ternary positive electrode materials prepared in Examples 1-6 and Comparative Examples 1-2, and the discharge capacity, cycle life, and capacity retention rate of the lithium batteries formed therefrom at different high voltages were tested. The surface alkali content of the high-voltage ternary positive electrode materials prepared in Examples 1-6 and Comparative Examples 1-2, and the capacity of the lithium batteries formed therefrom at different high voltages were tested and shown in Table 1.

[0068] The detection method for the surface alkali content of high voltage ternary cathode materials is: acid-base neutralization titration method;

[0069] The capacity test method of lithium battery at different high voltages is as follows: button battery test first cycle discharge capacity, test standards: voltage 3.0-4.4V, 3.0-4.5V, 3.0-4.6V, charge and discharge rate 0.1C, temperature 25℃, test compaction density 3.3g / cm 3 , nominal specific capacity 190mAh / g.

[0070] The lithium battery cycle life test method is: the number of cycles required for the button battery capacity retention rate to reach 80%. The test standards are: voltage 3.0-4.6V, charge and discharge rate 1C, temperature 45℃, and test compaction density 3.3g / cm 3 , nominal specific capacity 190mAh / g.

[0071] The capacity retention rate test method of lithium battery is: button battery test 100 cycles of discharge capacity retention rate, test standards are: voltage 3.0-4.4V, charge and discharge rate 1C, temperature 25℃, test compaction density 3.3g / cm 3 , nominal specific capacity 190mAh / g.

[0072] Table 1. Surface alkali content of high voltage ternary cathode materials prepared in Examples 1-6 and Comparative Examples 1-2, and the capacitance test results of the resulting lithium batteries at different high voltages

[0073] It can be seen that compared with Comparative Example 1, the residual alkali of the high-voltage ternary positive electrode material prepared in Example 1 is close to that of the high-voltage ternary positive electrode material prepared in Comparative Example 1, but has better performance in discharge capacity and material stability, indicating that after adding an appropriate amount of Li element, the surface alkali of the material will not increase significantly while effectively maintaining the discharge capacity and capacity retention rate of the material.

[0074] Compared with Comparative Example 1-2, the lithium batteries made of the high-voltage ternary positive electrode materials prepared in Example 1-6 performed well in terms of cycle life and capacity retention, proving that the high-voltage ternary positive electrode materials prepared in Example 1-6 have better stability.

[0075] Compared with Example 1 and Comparative Example 2, the surface alkali content of the high-voltage ternary positive electrode material prepared in Example 1 is reduced by more than 1000 ppm compared with Comparative Example 2, and the capacitance can reach 217.4 at a voltage of 4.6V, while the capacitance of Comparative Example 2 can only reach 209.4 at a voltage of 4.6V. This shows that the surface alkali content of the high-voltage ternary positive electrode material prepared in Example 1 of the present application is also reduced, and it has electrolyte resistance at high voltage, indicating that the addition of lithium element can improve the stability of the ternary positive electrode material, so that during the high-temperature calcination process, the cobalt element preferentially reacts with the lithium in the added lithium-containing additive, thereby overcoming the problem that the cobalt element reacts with the original lithium element in the ternary positive electrode material during the calcination and coating of the ternary positive electrode material, resulting in a reduction in the capacitance of the lithium-ion battery.

[0076] Comparing Examples 1-3, 5-6 and 4, it can be seen that when the lithium ion addition amount is in the range of 500-2000ppm, the high-voltage capacity performance of the lithium-ion battery formed by the prepared high-voltage ternary positive electrode material is better.

[0077] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a high voltage ternary positive electrode material, characterized in that: The steps include: S1, mixing a nickel-cobalt-manganese hydroxide precursor with a lithium source, and calcining to obtain a high-voltage positive electrode material intermediate; S2, mixing the high voltage positive electrode material intermediate with a cobalt element additive and a lithium element additive, and calcining to obtain a high voltage ternary positive electrode material, wherein the cobalt element doping amount in the cobalt element additive is 2000-10000ppm, and the lithium element doping amount in the lithium element additive is 500-2000ppm.

2. The method for preparing a high voltage ternary positive electrode material according to claim 1, characterized in that: The lithium element doping amount in the lithium element additive is 800 ppm, and the cobalt element doping amount in the cobalt element additive is 8000 ppm.

3. The method for preparing a high voltage ternary cathode material according to claim 2, characterized in that: The lithium element additive is at least one of lithium hydroxide and lithium carbonate; And / or, the cobalt element additive is at least one of cobaltous oxide, cobaltous hydroxide, cobaltous carbonate and cobalt tetroxide.

4. The method for preparing a high voltage ternary cathode material according to claim 3, characterized in that: The calcination temperature of step S2 is 650-950° C., the heating rate is 2-5° C. / min, and the calcination time is 4-6 h.

5. The method for preparing a high voltage ternary cathode material according to any one of claims 1 to 4, characterized in that: The calcination in step S1 includes pre-calcining a mixture of a nickel cobalt manganese hydroxide precursor and a lithium salt at a temperature of 650-850° C. for 4-6 hours at a heating rate of 2-5° C. / min in an oxidizing atmosphere, and then calcining at a temperature of 800-950° C. for 8-12 hours at a heating rate of 2-5° C. / min.

6. The method for preparing a high voltage ternary cathode material according to any one of claims 1 to 5, characterized in that: The composition of the nickel-cobalt-manganese hydroxide precursor in step S1 is Ni x Co y Mn 1-x-y (OH)2, where 0.5<x≤1, 0<y≤0.5; And / or, the nickel-cobalt-manganese hydroxide precursor has a specific surface area of ​​8-20 m 2 / g; And / or, the tap density of the nickel-cobalt-manganese hydroxide precursor is 1-2 g / cm 3 ; And / or, the median particle size D50 of the nickel-cobalt-manganese hydroxide precursor is 3-7 μm.

7. The method for preparing a high voltage ternary cathode material according to claim 6, characterized in that: In step S1, the lithium source is at least one of lithium carbonate, lithium hydroxide and lithium acetate.

8. The method for preparing a high voltage ternary cathode material according to claim 7, characterized in that: In the step S1, the molar ratio of the total molar number of nickel, cobalt and manganese elements in the nickel-cobalt-manganese hydroxide precursor to the molar ratio of the lithium element in the lithium salt is 1:0.9-1.

2.

9. A high-voltage ternary positive electrode material obtained by the method for preparing the high-voltage ternary positive electrode material according to claims 1-8.

10. Application of the high-voltage ternary positive electrode material prepared by the method for preparing the high-voltage ternary positive electrode material according to claims 1 to 8 in lithium-ion batteries.

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