A ternary positive electrode material and a precursor thereof, and a lithium ion battery

Abstract

The application provides a ternary positive electrode material and a precursor thereof and a lithium ion battery, relates to the technical field of new energy, and the ternary positive electrode material and the precursor thereof are of a porous structure and have a highly uniform pore distribution, provide a penetration path for electrolyte, greatly improve the penetration efficiency of the electrolyte, and are beneficial to the rapid and deep penetration of the electrolyte into the internal structure of the material. The proper porosity can improve the electrochemical performance of the material, and can also avoid a large decrease of tap density and compaction density, so that the material has a good volume energy density.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a precursor, a preparation method thereof, a ternary positive electrode material, a preparation method thereof, and a lithium ion battery. BACKGROUND

[0002] With the continuous development of the new energy industry, lithium ion batteries have been more and more widely and deeply researched, and the advantages and disadvantages of the positive electrode material are the key to the performance of the lithium ion battery. In real life, with the gradual increase of the demand for high-power materials, the requirement for the rate performance of the positive electrode material is also higher and higher. For the positive electrode material, the structure is of great importance to the rate performance, and the porosity, the size of the primary particles, and the specific surface area of the material are important influencing factors of the structure of the positive electrode material. Generally, the positive electrode material with the structural characteristics of high porosity, uniform pore distribution, and large specific surface area can better exert the electrochemical performance. The pore structure of the positive electrode material is well inherited from the pore structure of the precursor.

[0003] Therefore, the positive electrode material with high specific capacity, good rate performance, and cycle performance can be obtained by designing the structure of the positive electrode material precursor, such as increasing the porosity of the precursor, increasing the specific surface area of the precursor, and changing the morphology of the primary particles. However, too high porosity and specific surface area will cause the decrease of the structural strength of the material, which is easy to cause cracks or even breakage of the material, and finally leads to the decrease of the cycle performance, so the porosity and the structural strength should be well balanced. SUMMARY

[0004] The present application aims to provide a ternary positive electrode material and a precursor thereof with excellent performance, and aims to solve the problem that the existing ternary positive electrode material cannot balance the electrochemical performance and the structural strength performance.

[0005] To achieve the above object, the first aspect of the present application provides a ternary precursor, which has a chemical formula of Ni a Co b Mn c (OH)2, wherein a+b+c=1, 0<a<1, 0<b<1, 0<c<1; the internal porosity of the ternary precursor is 5-8%, and the pore uniformity coefficient R 2 ≥0.9,

[0006] Preferably, the pore uniformity coefficient R 2 ≥0.95;

[0007] Preferably, 0.4≤a≤0.6, 0.1≤b≤0.4, and 0.1≤c≤0.4.

[0008] Preferably, the specific surface area of the ternary precursor is 15-35m 2 / g.

[0009] Preferably, the primary particles of the ternary precursor are short needle-shaped or short filament-shaped, with a length of 200-400 nm and an aspect ratio of 8-12.

[0010] Preferably, the D50 of the ternary precursor is 7.0-11.0 μm; the span of the particle size distribution of the ternary precursor is 1.10-1.30. 50 Preferably, the D50 of the ternary precursor is 7.0-11.0 μm; the span of the particle size distribution of the ternary precursor is 1.10-1.30.

[0011] Preferably, the mesopores in the pores of the ternary precursor account for 50%-70%.

[0012] The second aspect of the present application further provides a preparation method of the ternary precursor described above, comprising:

[0013] A nickel-cobalt-manganese metal mixed solution is prepared according to the proportion of the ternary precursor;

[0014] The nickel-cobalt-manganese metal mixed solution, a precipitating agent and a complexing agent are added to the bottom liquid in the reaction kettle in a continuous production process to perform a co-precipitation reaction, the flow rate of the nickel-cobalt-manganese metal mixed solution is controlled to be 10-30 L / h, the reaction temperature, the pH value of the reaction system and the solid content in the reaction kettle are controlled, a co-precipitation reaction product is obtained, and the ternary precursor particles are obtained by washing the reaction product.

[0015] Preferably, the concentration of the complexing agent in the bottom liquid is 0.1-0.8 mol / L.

[0016] Preferably, the reaction temperature is controlled to be 50-70℃, and the solid content in the reaction kettle is 80-110 g / L.

[0017] Preferably, the pH value is 9.00-11.00.

[0018] Preferably, the precipitating agent comprises sodium hydroxide, and the complexing agent comprises ammonia.

[0019] The third aspect of the present application further provides a ternary positive electrode material, the expression of the chemical composition of which is LiNi x Co y Mn z O 2, wherein x+y+z=1, 0 x Co y Mn z O2, wherein x+y+z=1, 0 2

[0020] Preferably, the porosity uniformity coefficient R 2 ≥0.9.

[0021] Preferably, 0.4≤x≤0.6, 0.1≤y≤0.4, and 0.1≤z≤0.4.

[0022] ​Preferably, the specific surface area of the ternary positive electrode material is 1.5-3.0 m 2 / g.

[0023] Preferably, the primary particles of the ternary positive electrode material are in brick type, the inner core of the ternary positive electrode material is arranged in a loose and porous structure by disordering the primary particles, and the primary particles are arranged radially outward with the inner core as the center.

[0024] Preferably, the length of the primary particles of the ternary positive electrode material is 200-500 nm, the width is 50-150 nm, and the aspect ratio is greater than 3.

[0025] More preferably, the length of the primary particles of the ternary positive electrode material is 300-400 nm, the width is 70-90 nm, and the aspect ratio is 3-6.

[0026] Preferably, the D 50 of the ternary positive electrode material is 7-15 μm; and the particle size distribution span of the ternary positive electrode material is 1.1-1.4.

[0027] Preferably, the macropores in the pores of the ternary positive electrode material account for greater than or equal to 50%.

[0028] The fourth aspect of the present application further provides a preparation method of the ternary positive electrode material described above, comprising:

[0029] mixing a lithium source and the ternary precursor described above to obtain a mixture;

[0030] heating the mixture to 700-1000 °C at a rate of 1-10 °C / min, and holding for 8-15 h to obtain the ternary positive electrode material;

[0031] Preferably, the molar ratio of Li in the lithium source to the total molar amount of Ni, Co and Mn in the ternary precursor is 1-1.1:1.

[0032] Preferably, the mixture is heated to 700-1000 °C at a rate of 1-10 °C / min, and held for 8-15 h, specifically:

[0033] first, heated to 400-650 °C at a rate of 2-10 °C / min, and held for 2-6 h; and then heated to 700-1000 °C at a rate of 1-5 °C / min, and held for 10-15 h.

[0034] The fifth aspect of the present application further provides a lithium ion battery comprising the ternary positive electrode material described above.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] The ternary precursor provided in the application has a good pore structure, rich pores and a high uniformity of pore distribution, and the primary particles are small, and the ternary positive electrode material inherits the excellent structure of the precursor. The rich pore structure of the ternary positive electrode material provides a penetration path for the electrolyte, greatly improves the penetration efficiency of the electrolyte, and is beneficial to the rapid penetration of the electrolyte into the internal structure of the material. The appropriate porosity can improve the electrochemical performance of the material while avoiding a large decrease in the tap density and the compacted density, so that the material has a good volume energy density.

[0037] The primary particles of the ternary positive electrode material provided in the application are small and have a regular brick-shaped structure with a small size, so that the specific surface area and the porosity of the material are greatly improved, the rich pores can greatly increase the contact area with the electrolyte, thereby being beneficial to the maximum capacity of the material. The primary particles are arranged in a radial manner, which provides a structural basis for the rapid deintercalation of lithium ions under a large current, and is also beneficial to reducing the stress expansion between the primary particles, thereby reducing the generation of microcracks of the secondary particles formed by the aggregation of the primary particles in the cycle process, and enhancing the cycle life of the material.

[0038] The application provides a ternary positive electrode material with excellent performance and a precursor thereof. Under the premise of structural stability, the porosity and the uniformity of pore distribution are improved, and the obtained positive electrode material not only has a high specific capacity, but also has a good rate performance, that is, even under a large current, the positive electrode material has a high capacity and a retention rate, can realize fast charging and discharging under a large current, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope of the application.

[0040] Figure 1 The SEM image (left side) and the cross-sectional image (right side) of the ternary precursor of Example 1;

[0041] Figure 2 The linear relationship diagram of the uniformity of the pore distribution of the ternary precursor of Example 1;

[0042] Figure 3 The SEM image (left side) and the cross-sectional image (right side) of the ternary positive electrode material of Example 1;

[0043] Figure 4 The linear relationship diagram of the uniformity of the pore distribution of the ternary positive electrode material of Example 1;

[0044] Figure 5 The SEM image of the ternary positive electrode material of Example 2;

[0045] Figure 6 SEM image (left) and cross-sectional image (right) of the ternary precursor of Example 3;

[0046] Figure 7 SEM image of the ternary cathode material of Example 3;

[0047] Figure 8 SEM image (left) and cross-sectional image (right) of the ternary precursor of Comparative Example 1;

[0048] Figure 9 SEM image of the ternary cathode material of Comparative Example 1;

[0049] Figure 10 SEM image of the ternary cathode material of Comparative Example 2;

[0050] Figure 11 Charge-discharge curve of the coin cell of the ternary cathode material of Example 1 at 0.1 C;

[0051] Figure 12 Cycle performance curve of the coin cell of the ternary cathode material of Example 1 at 1 C for 50 cycles. DETAILED DESCRIPTION

[0052] As used herein the terms “includes,” “including,” “has,” “having,” “comprises,” “comprising,” “contains” or “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0053] The transitional phrase “consisting of’ excludes any element, step, or ingredient not specified. If used in the claims, this phrase shall cover only those aspects “as such” and does not include materials not specified and equivalents thereof except where equivalents would not be barred by statute. Where this phrase appears in the claims, it shall be open-ended, and the use of it does not exclude additional steps or components that are in connection with the only claimed combination of elements.

[0054] The transitional phrase “consisting of’ excludes any element, step, or ingredient not specified. If used in the claims, this phrase shall cover only those aspects “as such” and does not include materials not specified and equivalents thereof except where equivalents would not be barred by statute. Where this phrase appears in the claims, it shall be open-ended, and the use of it does not exclude additional steps or components that are in connection with the only claimed combination of elements.

[0055] When equivalent, concentration, or other value or parameter is expressed in a range, preferably a range, or a series of upper preferred limits, and lower preferred limits, it is to be understood that all ranges formed by any pair of any upper range limit or preferred limit, and any lower range limit or preferred limit, regardless of whether such range is separately disclosed, is expressly disclosed. For example, where a range "1-5" is disclosed, the disclosure is to be interpreted to include ranges "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," etc. When numerical ranges are disclosed, unless otherwise stated, the range is intended to include all integers and fractions within the range.

[0056] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0057] "Mass parts" refers to a basic unit of measurement that represents the mass ratio relationship of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the mass ratio of component A and component B is a:b. Or, the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0058] "And / or" is used to indicate that one or both of the described conditions can occur, for example, A and / or B includes (A and B) and (A or B).

[0059] The first aspect of the present application provides a ternary precursor, the chemical formula of which is Ni a Co b Mn c (OH)2, wherein a+b+c=1, 0

[0060] The present application designs the structure of the ternary precursor, so that the internal porosity is 5-8%, and the pore uniformity coefficient R 2≥0.9, the pore distribution is highly uniform, the structure is stable, the porosity is improved, and the ternary positive electrode material can inherit its structural performance. The precursor and the ternary positive electrode material obtained are of a porous structure and have a highly uniform pore distribution, which provides a penetration path for the electrolyte and greatly improves the penetration efficiency of the electrolyte, which is beneficial to the rapid penetration of the electrolyte into the internal structure of the material. The appropriate porosity improves the electrochemical performance of the material while avoiding a large decrease in the tap density and the compacted density, so that the material has a good volumetric energy density.

[0061] The internal porosity of the ternary precursor = (the internal cross-sectional pore area of the secondary particles / the cross-sectional area of the secondary particles) * 100%, the secondary particles are the primary particles aggregated to form the ternary precursor, the internal porosity of the ternary precursor is a range value, and is not limited to a specific value, and the porosities of different parts may be different, for example, can be 5%, 5.5%, 6%, 6.14%, 6.36%, 7%, 7.38%, 7.59% or 8%, or any value between 5% and 8%.

[0062] The pore uniformity coefficient R 2 is used to represent the uniformity of the pore distribution, and the specific verification steps are as follows:

[0063] Step one: regarding a single ternary precursor particle as a sphere, the cross-sectional circle of the sphere is calculated, and the circle is equally divided into n (n≥3) concentric circles;

[0064] Step two: the area of each concentric circle and the pore area are calculated;

[0065] Step three: the change x of the area of the concentric circle in different regions and the change y of the pore area corresponding to the region are calculated;

[0066] Step four: a linear relationship formula of x and y is established, and the correlation coefficient R 2 is calculated;

[0067] When R 2 ≥0.9, it is considered that the pore distribution is uniform. When R 2 is between 0.9 and 0.95, it is considered that the pore distribution is relatively uniform, and when R 2 ≥0.95, it is considered that the pore distribution is highly uniform.

[0068] When R 2 <0.9, it is considered that the pore distribution is not uniform.

[0069] In an embodiment, the mesopores in the pores of the ternary precursor account for 50-70%, wherein the mesopores are defined as pores with a pore size of 2-50 nm, also known as mesopores, and thus the pore size of the mesopores may, for example, be 2-10 nm, or 10-20 nm, or 20-50 nm. The mesopores in the pores of the ternary precursor account for 50-70%, for example, may be (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70)%, or any value between 50-70%. The mesopores will increase the internal contact area of the material compared to macropores, and the pore size is larger than micropores, and is not easy to block the pores.

[0070] Preferably, 0.4≤a≤0.6, 0.1≤b≤0.4, 0.1≤c≤0.4. Wherein, a may, for example, be 0.4, 0.44, 0.45, 0.50, 0.55, 0.56, or 0.6; b may, for example, be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4; c may, for example, be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4.

[0071] Preferably, the primary particles of the ternary precursor are short needle-shaped or short filament-shaped, with a length of 200-400 nm, for example, may be (200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, or 400) nm, and an aspect ratio of 8-12, for example, may be 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or 12.

[0072] The primary particles of the ternary precursor provided in the present application are small, which greatly improves the specific surface area and porosity of the ternary precursor. The abundant pores can greatly increase the contact area with the electrolyte, thereby facilitating the maximum capacity of the material.

[0073] Preferably, the specific surface area of the ternary precursor is 15-35 m 2 / g. The specific surface area of the ternary precursor may, for example, be (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35) m 2 / g. More preferably, the specific surface area of the ternary precursor is 25-35 m 2 / g.

[0074] Preferably, the D 50 is 7.0-11.0 μm; the span of the particle size distribution of the ternary precursor is 1.10-1.30. Among them, the physical meaning of D 50 50% of the particles are less than it, which can be measured by a Malvern 3000 laser particle size tester; the span of the particle size distribution means the width of the particle size distribution, which is used to represent the value of the uniformity of the particle size of the material, and the calculation method is: (D 90 -D 10 ) / D 50 .

[0075] The second aspect of the present application also provides a preparation method of the ternary precursor, comprising:

[0076] According to the proportion of the ternary precursor, a nickel-cobalt-manganese metal mixed solution is prepared;

[0077] The nickel-cobalt-manganese metal mixed solution, a precipitating agent and a complexing agent are added to the bottom liquid of a reaction kettle in a continuous production process to perform a co-precipitation reaction, the flow rate of the nickel-cobalt-manganese metal mixed solution is controlled to be 10-30 L / h, the reaction temperature, the pH value of the reaction system and the solid content in the reaction kettle are controlled, the co-precipitation reaction product is obtained, and the ternary precursor particles are obtained by washing the reaction product;

[0078] Among them, the nickel-cobalt-manganese metal mixed solution can be obtained by mixing soluble salts of nickel, cobalt and manganese, and the soluble salts can be at least one of nitrate, chloride and sulfate. The total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese metal mixed solution can be 0.8-4.0 mol / L, for example, it can be (0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 or 4.0) mol / L.

[0079] Among them, the concentration of the complexing agent in the bottom liquid is 0.1-0.8 mol / L, for example, it can be (0.15, 0.2, 0.3, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7 or 0.8) mol / L. The precipitating agent includes sodium hydroxide, the concentration of the sodium hydroxide solution is 5-12 mol / L, and the complexing agent includes ammonia water, the concentration of the ammonia water is 1.0-10 mol / L.

[0080] The flow rate of the mixed nickel-cobalt-manganese metal solution is, for example, (10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30) L / h; the pH value of the reaction system is 9.00-11.00, for example, (9.00, 9.10, 9.20, 9.30, 9.40, 9.50, 9.60, 9.70, 9.80, 9.90, 10.0, 10.05, 10.1, 10.15, 10.2, 10.25, 10.3, 10.35, 10.4, 10.45, 10.50, 10.60, 10.70, 10.80 or 10.90), or fluctuates within any small range between 9.00 and 11.00.

[0081] Preferably, the reaction temperature is controlled at 50-70℃, and the solid content in the reaction kettle is 80-110 g / L.

[0082] The third aspect of the present application also provides a ternary positive electrode material, the chemical composition of which is expressed as LiNi x Co y Mn z O2, wherein x+y+z=1, 0<x<1, 0<y<1, 0<z<1; the porosity of the ternary positive electrode material is 10%-15%, and the pore uniformity coefficient R 2 ≥0.9.

[0083] The porosity and the pore uniformity coefficient R 2 of the ternary positive electrode material are defined in the same way as the porosity and the pore uniformity coefficient R 2 of the ternary precursor, and are not described here again. Preferably, the pore uniformity coefficient R 2 of the ternary positive electrode material is ≥0.95.

[0084] The ternary positive electrode material provided by the present application inherits the excellent structure of the precursor, is a porous structure with highly uniform pore distribution, provides a penetration path for the electrolyte, greatly improves the penetration efficiency of the electrolyte, and is conducive to the rapid penetration of the electrolyte into the internal structure of the material. The appropriate porosity can improve the electrochemical performance of the material while avoiding a large decrease in the tap density and the compacted density, so that the material has a good volumetric energy density.

[0085] Preferably, 0.4≤x≤0.6, 0.1≤y≤0.4, 0.1≤z≤0.4. Wherein, x may be 0.4, 0.44, 0.45, 0.50, 0.55, 0.56, 0.6, for example; y may be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4, for example; z may be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4, for example.

[0086] Preferably, the proportion of large pores in the pores of the ternary positive electrode material is greater than or equal to 50%, wherein the large pores are defined as pores with a pore size greater than 50 nm. Since the proportion of mesopores in the pores of the ternary precursor is relatively large, the primary particles grow during the later sintering process, and the pores will fuse and become larger, so the pore size of the ternary positive electrode material will become larger.

[0087] Preferably, the primary particles of the ternary positive electrode material are in a brick type, and the core of the ternary positive electrode material is arranged in a loose and porous structure by the primary particles in a random manner, and the primary particles are arranged radially outward with the core as the center.

[0088] The primary particles of the ternary positive electrode material are arranged radially, which provides a structural basis for the rapid deintercalation of lithium ions under large current conditions, and is also conducive to reducing the stress expansion between the primary particles, thereby reducing the generation of microcracks of the secondary particles formed by the aggregation of the primary particles during the cycle process, and enhancing the cycle life of the material.

[0089] Preferably, the length of the primary particles of the ternary positive electrode material is 200-500 nm, the width is 50-150 nm, and the aspect ratio is greater than 3.

[0090] More preferably, the length of the primary particles of the ternary positive electrode material is 300-400 nm, the width is 70-90 nm, and the aspect ratio is 3-6.

[0091] The primary particles of the ternary positive electrode material are small and in a regular brick type structure with small size, so that the specific surface area and porosity of the material are greatly improved, and the rich pores can greatly increase the contact area with the electrolyte, thereby facilitating the maximum capacity of the material.

[0092] Preferably, the specific surface area of the ternary positive electrode material is 1.5-3.0 m 2 / g.

[0093] Preferably, the D 50 of the ternary positive electrode material is 7-15 μm; and the particle size distribution span of the ternary positive electrode material is 1.1-1.4.

[0094] The fourth aspect of the present application further provides a preparation method of the ternary positive electrode material described above, comprising:

[0095] mixing the lithium source and the ternary precursor to obtain a mixture;

[0096] heating the mixture to 700-1000℃ at a rate of 1-10℃ / min, and holding for 8-15h to obtain the ternary cathode material.

[0097] The sintering temperature is determined by the content of Ni, and different content of Ni will result in different sintering temperature. Generally, low nickel requires high temperature, and high nickel requires low temperature. The sintering temperature can be adjusted in the range of 700-1000℃ according to the chemical formula of the ternary cathode material. The sintering temperature can be, for example, (700, 710, 720, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990 or 1000)℃. However, for the ternary cathode material with the same content of Ni, the sintering temperature of the present application is lower than that of the prior art.

[0098] Preferably, the molar ratio of Li in the lithium source to the total molar amount of Ni, Co and Mn in the ternary precursor is 1-1.1:1.

[0099] Preferably, the mixture is heated to 700-1000℃ at a rate of 1-10℃ / min, and held for 8-15h, specifically:

[0100] First, heated to 400-650℃ at a rate of 2-10℃ / min, and held for 2-6h; then heated to 700-1000℃ at a rate of 1-5℃ / min, and held for 10-15h.

[0101] The fifth aspect of the present application also provides a lithium ion battery comprising the ternary cathode material described above.

[0102] The present application provides a ternary cathode material with excellent performance and its precursor. Under the premise of stable structure, the porosity and uniform pore distribution are improved to obtain a cathode material with not only high specific capacity, but also good rate performance, high capacity and retention rate even under large current, and the ability to realize fast charging and discharging under large current. The cathode material has good application prospect in lithium ion batteries.

[0103] The embodiments of the present application will be described in detail below with reference to specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0104] Example 1

[0105] Step one: configure nickel, cobalt, manganese sulfate crystals (molar ratio of nickel: cobalt: manganese is 0.5:0.2:0.3) into a uniform ternary metal salt mixed solution of 2 mol / L.

[0106] Step two: preparation of the base solution condition: add 60 L of water into a 100 L reaction kettle, start stirring, the rotation speed is 510 r / min, add ammonia water, adjust the ammonia concentration in water to 0.15 mol / L, and add sodium hydroxide solution, adjust the pH to 10.00-10.50, and heat to 60°C, under nitrogen protection. Co-precipitation reaction: add 2 mol / L of nickel-cobalt-manganese mixed sulfate, 2 mol / L of ammonia water and 6 mol / L of sodium hydroxide solution into the reaction kettle with the prepared base solution through the form of peristaltic pump, at a uniform speed and in a parallel flow, and control the flow rate of the nickel sulfate mixed metal salt to be 25 L / h, the reaction temperature is controlled to be 60°C, the solid content of the reaction kettle is 105 g / L, the pH of the reaction system is controlled to be 10.00-10.50, and the particle size is stabilized.

[0107] Step three: centrifugal washing of the co-precipitated reaction product of step two, control the temperature of the hot alkali tank to be 70±5°C, the hot alkali concentration is 1.3 mol / L, wash until the S content in the material is ≤0.27%, then wash with pure water, control the temperature of the hot pure water tank to be 75°C±5°C, wash until the Na content in the material is ≤0.030%, stop washing, and use the centrifugal machine to dewater and dry. Dry the material in an oven, use a 400 mesh sieve to sieve, and obtain the ternary precursor of Example 1.

[0108] The 5000 times scanning electron microscope morphology result graph of the ternary precursor of Example 1 is shown in Figure 1 (left side), the cross-sectional view is shown in Figure 1 (right side), the secondary particle shape is spherical or spherical-like, the primary particle is short filamentous, there are rich pores inside the sphere and the pores are highly uniform, the primary particle is 300 nm long, and the aspect ratio is 10. After detection, the chemical formula is Ni 0.5 Co 0.2 Mn 0.3 (OH)2, D 50 = 10.556 μm, span: 1.20, specific surface area = 29.92 m 2 / g.

[0109] According to Figure 1The cross-sectional view (right) is used to calculate the area of different regions A, B, C, D by image J gray scale analysis method, and the porosity is calculated, A, B, C, D are concentric circles, wherein A represents the entire cross section of the precursor particle, the porosity of A is the porosity of the entire particle, the porosity of the ternary precursor of Example 1 is 6.14%. The porosity distribution uniformity verification calculation table of the ternary precursor of Example 1 is shown in Table 1, and the porosity distribution uniformity linear relationship graph is obtained according to the data in Table 1 as shown in Figure 2 The uniformity coefficient R 2 is 0.9898, and the porosity distribution of the ternary precursor of Example 1 is highly uniform.

[0110] Table 1 Porosity distribution uniformity verification calculation table of ternary precursor of Example 1

[0111]

[0112] The nitrogen isothermal adsorption-desorption method is used to calculate the pore volume ratio of the ternary precursor, and the results are shown in Table 2. According to Table 2, it is known that the mesopore ratio in the pores of the ternary precursor of Example 1 is 64.88%.

[0113] Table 2 Pore volume ratio report of ternary precursor of Example 1

[0114]

[0115]

[0116] Step four: the precursor obtained in step three and Li2CO3 are mixed in a high-speed mixer at a molar ratio of 1:1.05.

[0117] Step five: the mixture of step four is placed in a box-type atmosphere furnace for sintering. First, heat to 650℃ at a heating rate of 3℃ / min, sinter for 2h, then heat to 840℃ at a heating rate of 1℃ / min, sinter for 10h, and cool to room temperature to obtain the LiNi 0.5 Co 0.2 Mn 0.3 O2 ternary positive electrode material of Example 1.

[0118] The scanning electron microscope morphology result graph of the ternary positive electrode material of Example 1 is shown in Figure 3 (left), and the CP graph is shown in Figure 3 (right), the secondary particle shape is spherical or spherical, the inside of the sphere has rich pores and is highly uniform, the primary particle is brick-shaped and is arranged in a radial manner, the primary particle is 300nm long and 70nm wide, the aspect ratio is 4.28, the specific surface area is 2.61m 2 / g, the span is 1.27, and the D50 9.868 μm.

[0119] According to Figure 3 The cross-sectional view (right side) was used to calculate the area of the different regions A, B, and C, the pore area, and the porosity using the image J grayscale analysis method. A, B, and C are concentric circles, where A represents the entire cross-section of the ternary cathode material particle, and the porosity of A is the porosity of the entire particle. The porosity of the ternary cathode material of Example 1 was 13.38%. The calculation table for verifying the uniformity of the pore distribution of the ternary cathode material of Example 1 is shown in Table 3, and the linear relationship diagram of the pore distribution uniformity is shown in Figure 4 , the pore uniformity coefficient R 2 was 0.9982, and the pore distribution was highly uniform.

[0120] Table 3. Calculation table for verifying the uniformity of the pore distribution of the ternary cathode material of Example 1

[0121]

[0122]

[0123] The nitrogen isothermal adsorption-desorption method was used to calculate the pore volume ratio of the ternary cathode material, and the results are shown in Table 4. According to Table 4, it was calculated that the macropore ratio in the pores of the ternary cathode material of Example 1 was 64.91%.

[0124] Table 4. Pore volume ratio report of the ternary cathode material of Example 1

[0125] ID Pore diameter range (nm) Pore volume (cm 3 / g) Pore volume percentage (%) 1 2.00-10.00 0.00243 13.59 2 10.00-20.00 0.00136 7.57 3 20.00-50.00 0.00250 13.94 4 >50.00 0.01163 64.91

[0126] The ternary cathode material obtained in Example 1 was used to prepare a button cell, and the charge-discharge curve results under 0.1C conditions are shown in Figure 11 , the 50-week cycle performance curve under 1C conditions is shown in Figure 12 , the 0.1C initial charge was 192.1 mAh / g, the 0.1C initial discharge efficiency was 95.39%, and the 5C / 1C rate performance was 92.32%.

[0127] Example 2

[0128] The difference between Example 2 and Example 1 is that the same precursor as that used in Example 1 was selected, and different sintering conditions were used for sintering.

[0129] Steps 1 to 4 are the same as in Example 1.

[0130] Step five: put the mixture into a box atmosphere furnace for sintering. First, heat to 650℃ at a heating rate of 5℃ / min, sinter for 4h, then heat to 860℃ at a heating rate of 2℃ / min, sinter for 12h, and after cooling to room temperature, LiNi 0.5 Co 0.2 Mn 0.3 O2 ternary positive electrode material is obtained.

[0131] The SEM image of the ternary positive electrode material of Example 2 is shown in Figure 5 Figure 1. The secondary particles are spherical or spherical-like in shape, and the primary particles are brick-shaped. The inside of the sphere has abundant pores and is highly uniform, with a specific surface area of 2.08m 2 / g. The primary particles are 320nm long and 75nm wide, with an aspect ratio of 4.27, a span of 1.15, and a D 50 of 10.147μm.

[0132] The porosity of the ternary positive electrode material of Example 2 is calculated to be 12.71% according to the same method as Example 1, and the pore uniformity coefficient R 2 is 0.9975.

[0133] The ternary positive electrode material obtained in Example 2 is used to prepare a button cell, which has a first charge of 191.1mAh / g and a first discharge efficiency of 95.59% under 0.1C charging and discharging conditions, and a 5C / 1C rate performance of 90.1%.

[0134] Example 3

[0135] The difference between Example 3 and Example 1 is that Example 3 selects a different precursor from Example 1, and uses the same sintering conditions for sintering.

[0136] Step one: configure the nickel, cobalt, and manganese sulfate crystals (molar ratio of nickel: cobalt: manganese is 0.55:0.1:0.35) into a uniform ternary metal salt mixed solution of 2mol / L.

[0137] Step two: preparation of the base solution: add 60L of water to a 100L reaction kettle, start stirring at a speed of 650r / min, add ammonia water, adjust the ammonia concentration in the water to 0.45mol / L, and add sodium hydroxide solution, adjust the pH to 9.5-10.0, and heat to 65℃ under nitrogen protection. Co-precipitation reaction: add 2mol / L of nickel-cobalt-manganese mixed sulfate, 2mol / L of ammonia water, and 6mol / L of sodium hydroxide solution to the reaction kettle in the form of a peristaltic pump at a uniform speed and in a parallel flow, and control the flow rate of the nickel sulfate mixed metal salt to be 20L / h, the reaction temperature to be 65℃, the solid content of the reaction kettle to be 95g / L, and the pH of the reaction system to be 9.5-10.0 to stabilize the particle size.

[0138] Step three: centrifugal washing was performed on the reaction product of step two co-precipitation, the temperature of the washing hot alkali tank was controlled at 70±5℃, the hot alkali concentration was 1.3 mol / L, and the washing was stopped until the S content in the material was ≤0.27%, then pure water was used for washing, the temperature of the washing hot pure water tank was controlled at 75℃±5℃, and the washing was stopped until the Na content in the material was ≤0.030%, then the centrifugal dewatering and drying were performed. The material was dried in an oven, sieved using a 400 mesh screen, and finally the high porosity nickel-cobalt-manganese ternary precursor of Example 3 was prepared.

[0139] The scanning electron microscope morphology result graph of the ternary precursor of Example 3 is shown in Figure 6 (left side), and the cross-sectional view is shown in Figure 6 (right side), the secondary particle shape is spherical or spherical-like, there are rich pores inside the sphere and the distribution is highly uniform, and the primary particle is short filamentous. After detection, the chemical formula is Ni 0.55 Co 0.1 Mn 0.35 (OH)2, D 50 = 10.201 μm, span: 1.28, specific surface area = 26.30 m 2 / g, the primary particle length is 350 nm, and the aspect ratio is 8.75.

[0140] The porosity of the ternary precursor of Example 3 was calculated to be 5.93% according to the same method as Example 1, and the uniformity coefficient R 2 was 0.9801.

[0141] Steps four to five were the same as Example 1, and the LiNi 0.55 Co 0.1 Mn 0.35 O2 ternary positive electrode material of Example 3 was obtained.

[0142] The SEM graph of the ternary positive electrode material of Example 3 is shown in Figure 7 , the shape is spherical or spherical-like, the primary particle is brick-shaped, there are rich pores inside the sphere and the distribution is highly uniform, the specific surface area is 2.45 m 2 / g, the primary particle length is 350 nm, the width is 70 nm, the aspect ratio is 5, the span is 1.21, and D 50 is 10.058 μm.

[0143] The porosity of the ternary positive electrode material of Example 3 was calculated to be 11.81% according to the same method as Example 1, and the pore uniformity coefficient R 2 was 0.9836.

[0144] The ternary cathode material obtained in Example 3 was used to prepare a coin cell. The first charge efficiency under 0.1C conditions was 192.8 mAh / g, the first discharge efficiency was 95.42%, and the 5C / 1C rate performance was 91.02%.

[0145] Comparative Example 1

[0146] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses different precursors, but the sintering conditions are the same.

[0147] Step 1: Prepare a 2 mol / L homogeneous ternary metal salt mixed solution by preparing nickel, cobalt and manganese sulfate crystals (nickel:cobalt:manganese molar ratio of 0.55:0.05:0.4).

[0148] Step 2: Preparation of the base solution: Add 60L of water to a 100L reactor, start stirring at 510 rpm, add ammonia water to adjust the ammonia concentration to 1 mol / L, and add sodium hydroxide solution to adjust the pH to 11.10–11.50. Heat to 60℃ under nitrogen protection. Coprecipitation reaction: Add 2 mol / L nickel-cobalt-manganese mixed sulfate, 2 mol / L ammonia water, and 6 mol / L sodium hydroxide solution to the reactor in a uniform, concurrent flow using a peristaltic pump. Control the flow rate of the nickel sulfate mixed metal salt at 6 L / h, maintain the reaction temperature at 60℃, ensure the solid content in the reactor is 125 g / L, and control the pH of the reaction system to 11.10–11.50 to achieve particle size stability.

[0149] Step 3: The reaction product co-precipitated in Step 2 is centrifuged and washed. The temperature of the hot alkali bath is controlled at 70±5℃, and the concentration of hot alkali is 1.3mol / L. Washing continues until the sulfur content in the material is ≤0.10%. Then, it is washed with pure water. The temperature of the hot pure water bath is controlled at 75℃±5℃. Washing continues until the sodium content in the material is ≤0.030%. Washing is then stopped, and the material is dehydrated using a centrifuge. The material is dried in an oven and sieved through a 400-mesh sieve to finally obtain the nickel-cobalt-manganese ternary precursor of Comparative Example 1.

[0150] The morphology of the ternary precursor in Comparative Example 1, obtained by scanning electron microscopy at 5000x magnification, is shown in the figure below. Figure 8 As shown on the left, the morphology of the cross-section under an 8000x scanning electron microscope is as follows. Figure 8 As shown on the right, the secondary particles are spherical or near-spherical in shape, with a relatively dense interior and few pores, while the primary particles are stacked. Their chemical formula, as determined by testing, is Ni. 0.55 Co 0.05 Mn 0.4 (OH)2, D 50 =10.051μm, span: 1.23, specific surface area = 9.63m² 2 / g.

[0151] The porosity of the ternary precursor of Comparative Example 1 was calculated to be 3.30%, and the uniformity coefficient R of the porosity was 0.8785. 2

[0152] Step four: The precursor obtained in step three was mixed with Li2CO3 in a molar ratio of 1:1.05 in a high-speed mixer.

[0153] Step five: The mixture was placed in a box-type atmosphere furnace for sintering. First, the temperature was raised to 650°C at a rate of 3°C / min, sintered for 2h, then the temperature was raised to 840°C at a rate of 1°C / min, sintered for 10h, and cooled to room temperature to obtain the LiNi 0.55 Co 0.05 Mn 0.4 O2 ternary positive electrode material of Comparative Example 1.

[0154] The SEM image of the ternary positive electrode material of Comparative Example 1 is shown in Figure 9 , which is spherical or spherical in shape, and the primary particles are square, the inside of the ball is relatively dense, the specific surface area is 0.13m 2 / g, the primary particle length is 500nm, the width is 400nm, the aspect ratio is 1.25, the D 50 is 10.905μm, and the span is 1.28. The porosity of the ternary positive electrode material of Comparative Example 1 was calculated to be 4.01% by the same method as in Example 1, and the uniformity coefficient R of the porosity 2 was 0.8856.

[0155] The ternary positive electrode material obtained in Comparative Example 1 was used to prepare a button cell, which had a first charge of 188.6mAh / g and a first discharge efficiency of 86.23% under 0.1C charge-discharge conditions, and a 5C / 1C rate performance of 76.6%.

[0156] Comparative Example 2

[0157] Comparative Example 2 differs from Example 1 in that Comparative Example 2 uses the same precursor as Example 1, but different sintering conditions.

[0158] Steps one to three are the same as in Example 1.

[0159] Step four: The precursor obtained in step three was mixed with Li2CO3 in a molar ratio of 1:1.05 in a high-speed mixer.

[0160] ​Step 5: The mixture is placed in a box-type atmosphere furnace for sintering. First, the temperature is increased to 650℃ at a heating rate of 5℃ / min and sintered for 2 hours. Then, the temperature is increased to 910℃ at a heating rate of 3℃ / min and sintered for 10 hours. After cooling to room temperature, LiN is obtained. i0.5 Co 0.2 Mn 0.3 O2 cathode material.

[0161] SEM image of the ternary cathode material in Comparative Example 2 is shown below. Figure 10 As shown, the secondary particles are spherical or near-spherical in shape. Compared to Example 1, due to the increased sintering temperature, the primary particles of the ternary cathode material grow into square shapes, with reduced internal pores and a specific surface area of ​​0.50 m². 2 / g, primary particle length 400nm, width 250nm, aspect ratio 1.6, span 1.22, D 50 It is 9.702 μm.

[0162] The porosity of the ternary cathode material in Comparative Example 2 was calculated to be 6.58% using the same method as in Example 1, and the pore uniformity coefficient R was... 2 It is 0.9814.

[0163] In Comparative Example 2, by changing the sintering regime and increasing the sintering temperature, the primary particles of the prepared cathode material were significantly larger, and the porosity was significantly reduced, resulting in a decrease in rate performance. Therefore, the setting of sintering conditions has a significant impact on the pore structure of the material, and thus affects the rate performance of the material.

[0164] The ternary cathode material obtained in Comparative Example 2 was used to prepare a coin cell. The first charge efficiency under 0.1C conditions was 190.9 mAh / g, the first discharge efficiency was 91.31%, and the rate performance was 82.7%.

[0165] The precursor performance parameters of Examples 1 to 3, and Comparative Examples 1 and 2 are shown in Table 5.

[0166] Table 5. Precursor performance parameters for each embodiment and comparative example.

[0167]

[0168] The ternary cathode materials and battery performance parameters of Examples 1 to 3, and Comparative Examples 1 and 2 are shown in Table 6.

[0169] Table 6. Ternary cathode materials and battery performance parameters for each embodiment and comparative example.

[0170]

[0171] According to Table 5 and Table 6, the positive electrode materials prepared in Examples 1 to 3 have the characteristics of high porosity and uniform pore distribution, which determine that the batteries prepared from the positive electrode materials of Examples 1 to 3 have very high rate performance, and even under the condition of 5C / 1C large current, the rate performance can reach more than 90%, and the 0.1C initial discharge efficiency can reach more than 95%.

[0172] And the rate performance of the positive electrode material prepared in Example 1 is the best, and the electrochemical performance is also excellent, the 0.1C initial discharge efficiency can be as high as more than 95%, the 0.1C initial discharge capacity can reach 192.1mAh / g, and the high capacity, high initial efficiency and high rate performance are the outstanding characteristics of the electrochemical performance.

[0173] And in Comparative Example 1, the prepared precursor primary particles are laminated, have a small specific surface, are relatively dense inside, have fewer pores, and the porosity is only 3.30%, so compared with Examples, the rate performance of the battery of Comparative Example 1 is poor, only 76.6%.

[0174] In Comparative Example 2, by changing the sintering system and increasing the sintering temperature, the prepared positive electrode material primary particles are significantly increased, the porosity is significantly reduced, and the rate performance is reduced. Therefore, the setting of the sintering system has a great influence on the pore structure of the positive electrode material, and further affects the rate performance of the material.

[0175] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0176] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in the BACKGROUND section is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A ternary precursor, characterized in that, Its general chemical formula is Ni a Co b Mn c (OH)₂, where a+b+c=1, 0<a<1, 0<b<1, 0<c<1; the internal porosity of the ternary precursor is 5~8%, and the porosity uniformity coefficient R 2 ≥0.9; Wherein, the internal porosity of the ternary precursor = ((area of ​​pore region in the internal cross section of secondary particles / area of ​​cross section of secondary particles) × 100%). Among them, the porosity coefficient R 2 This is used to represent the uniformity of pore distribution, and its verification steps are as follows: Step 1: Treat a single ternary precursor particle as a sphere, and calculate based on the circular cross-section of the sphere to divide the circle into n (n≥3) concentric circles; Step 2: Calculate the area of ​​each concentric circle and the area of ​​the pores; Step 3: Calculate the change in the area of ​​concentric circles (x) in different regions and the corresponding change in the pore area (y). Step 4: Establish a linear relationship between x and y, and calculate the correlation coefficient R. 2 .

2. The ternary precursor according to claim 1, characterized in that, The pore uniformity coefficient R 2 ≥0.

95.

3. The ternary precursor according to claim 1, characterized in that, 0.4≤a≤0.6, 0.1≤b≤0.4, 0.1≤c≤0.

4.

4. The ternary precursor according to claim 1, characterized in that, The specific surface area of ​​the ternary precursor is 15~35m². 2 / g.

5. The ternary precursor according to claim 1, characterized in that, The primary particles of the ternary precursor are short needle-shaped or short filament-shaped, with a length of 200~400nm and an aspect ratio of 8~12.

6. The ternary precursor according to any one of claims 1 to 5, characterized in that, The ternary precursor D 50 The particle size distribution is 7.0~11.0 μm; the particle size distribution span of the ternary precursor is 1.10~1.

30.

7. The ternary precursor according to any one of claims 1 to 5, characterized in that, The mesopores in the ternary precursor account for 50% to 70%.

8. A method for preparing a ternary precursor as described in any one of claims 1 to 7, characterized in that, include: Prepare a nickel-cobalt-manganese metal mixed solution according to the ratio of the ternary precursors; The nickel-cobalt-manganese metal mixed solution, precipitant, and complexing agent are added to the bottom liquid of the reactor according to a continuous production process to carry out a co-precipitation reaction. The flow rate of the nickel-cobalt-manganese metal mixed solution is controlled at 10~30L / h, and the reaction temperature, pH value, and solid content in the reactor are controlled to obtain the co-precipitation reaction product. The reaction product is washed to obtain the ternary precursor particles.

9. The method for preparing the ternary precursor according to claim 8, characterized in that, The concentration of the complexing agent in the substrate is 0.1~0.8 mol / L.

10. The method for preparing the ternary precursor according to claim 8, characterized in that, The reaction temperature is controlled at 50~70℃, and the solid content in the reaction vessel is 80~110g / L.

11. The method for preparing the ternary precursor according to claim 8, characterized in that, The pH value is 9.00~11.

00.

12. The method for preparing the ternary precursor according to claim 8, characterized in that, The precipitant includes sodium hydroxide, and the complexing agent includes ammonia.

13. A ternary cathode material, characterized in that, Its chemical composition is expressed as LiNi x Co y Mn z O2, where x + y + z = 1, 0 < x < 1, 0 < y < 1, 0 < z < 1; the porosity of the ternary cathode material is 10%~15%, and the pore uniformity coefficient R 2 ≥0.9; Wherein, the porosity of the ternary cathode material = ((area of ​​pore region inside the secondary particle cross section / area of ​​secondary particle cross section) × 100%). Among them, the porosity coefficient R 2 This is used to represent the uniformity of pore distribution, and its verification steps are as follows: Step 1: Treat a single ternary cathode material particle as a sphere, and calculate based on the circular cross-section of the sphere to divide the circle into n (n≥3) concentric circles; Step 2: Calculate the area of ​​each concentric circle and the area of ​​the pores; Step 3: Calculate the change in the area of ​​concentric circles (x) in different regions and the corresponding change in the pore area (y). Step 4: Establish a linear relationship between x and y, and calculate the correlation coefficient R. 2 .

14. The ternary cathode material according to claim 13, characterized in that, Pore ​​uniformity coefficient R 2 ≥0.

95.

15. The ternary cathode material according to claim 13, characterized in that, 0.4≤x≤0.6, 0.1≤y≤0.4, 0.1≤z≤0.

4.

16. The ternary cathode material according to claim 13, characterized in that, The specific surface area of ​​the ternary cathode material is 1.5~3.0 m². 2 / g.

17. The ternary cathode material according to claim 13, characterized in that, The primary particles of the ternary cathode material are brick-shaped, and the core of the ternary cathode material is formed by the disordered arrangement of the primary particles into a loose and porous structure. The primary particles are arranged radially outward from the core.

18. The ternary cathode material according to claim 13, characterized in that, The primary particle length of the ternary cathode material is 200~500nm, the width is 50~150nm, and the aspect ratio is greater than 3.

19. The ternary cathode material according to claim 18, characterized in that, The primary particle length of the ternary cathode material is 300~400nm, the width is 70~90nm, and the aspect ratio is 3~6.

20. The ternary cathode material according to any one of claims 13 to 19, characterized in that, The ternary cathode material D 50 The particle size distribution is 7~15μm; the particle size distribution span of the ternary cathode material is 1.1~1.

4.

21. The ternary cathode material according to any one of claims 13 to 19, characterized in that, The ternary cathode material has a macropore ratio of ≥50%.

22. A method for preparing a ternary cathode material as described in any one of claims 13 to 21, characterized in that, include: A mixture is obtained by mixing a lithium source and the ternary precursor according to any one of claims 1 to 7; The mixture is first heated to 400-650°C at a rate of 2-10°C / min and held for 2-6 hours; then heated to 700-860°C at a rate of 1-5°C / min and held for 10-15 hours to obtain the ternary cathode material.

23. The method for preparing the ternary cathode material according to claim 22, characterized in that, The molar ratio of Li in the lithium source to the total molar ratio of Ni, Co, and Mn in the ternary precursor is 1 to 1.1:

1.

24. A lithium-ion battery, characterized in that, Includes the ternary cathode material as described in any one of claims 13 to 21.

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