Cathode material for lithium-ion batteries and method for manufacturing the same, lithium-ion battery

Abstract

The present invention provides a positive electrode material for lithium-ion batteries that exhibits a uniform coating effect, has an appropriate specific surface area and porosity, lacks a passivation layer, has high energy density, and good rate performance, as well as a method for manufacturing the same, and a lithium-ion battery. [Solution] Surface Ni of the positive electrode material 3+ Content and the internal Ni of the positive electrode material 3+ The content ratio is 0.95-1:1, and in the positive electrode material, the content of mixed arrangement nickel is 3% or less. The surface and interior of the positive electrode material of the lithium-ion battery 3+ The near-same content and low mixed arrangement nickel content prevent the formation of a NiO passivation layer in the cathode material, reduce the loss of surface-active lithium, and lithium-ion batteries containing this cathode material have improved capacity, rate performance, and cycle performance.

Description

[Technical Field]

[0001] The present invention relates to the field of lithium-ion batteries, and more specifically to the positive electrode material of a lithium-ion battery and This relates to the manufacturing method of lithium-ion batteries. [Background technology]

[0002] In recent years, with the worsening oil and energy crisis and environmental pollution problems, electric vehicles around the world have become traditional It is rapidly developing on new circuits as an alternative to conventional automobiles. At the same time, electric vehicles The performance demands for high energy density and long cycle life of power batteries installed in electric vehicles are also increasing. I'm waiting.

[0003] As the most expensive and performance-enhancing component of a battery, lithium is used for the cathode material. It has been widely researched, developed, and applied in ion-powered battery systems, and among them, layered lithium The umnickelcobaltmanganesealuminate multicomponent material has high specific capacity and stability, and is extremely It has the potential for development. To meet the increasingly urgent demands for high energy density and safety, Increasing the Ni content in multi-component materials increases energy density, and also doping and Combining various methods to control the rate and circulation performance of materials is a universal goal for both the market and researchers. This is a difficult choice.

[0004] As nickelization increases, traditional wet coating methods lead to the loss of surface-active lithium. It is easy to use, and an electrochemically active passivation layer is generated upon contact between the material and water. Furthermore, the impedance of the material increases, affecting its energy density and rate performance. Furthermore, the water washing process is complex, has many influencing factors, and the cost of filtrate recovery is high. Therefore, more and more research is focusing on dry coating processes for high-nickel materials. This not only effectively avoids the above problems, but also simplifies the manufacturing process. It has low stress, high consistency and reproducibility. For example, CN106784675A is a lithium battery This invention provides a dry coating method for cathode materials, in which the coating material is first pre-mixed with boric acid, and then the primary sintered material The material is mixed with other materials and fired to obtain the finished positive electrode material. During this process, the coating material is in sufficient contact. It forms a solid molten material, provides a uniform coating effect, and bonds tightly after firing, preventing the coating layer from peeling off. This method not only shortens the production cycle but also ensures uniformity of the coating and the coating material Exposure to high temperatures can also form an ideal glassy coating, improving the stability of the material. .

[0005] However, directly dry coating primary sintered materials still faces many challenges. One of the most major problems is that the specific surface area and porosity of primary sintered materials that have not been washed with water are not open. This prevents the subsequent coating, and the specific surface area of ​​the coating particles is further reduced, resulting in filled pores. There is a significant difference in the specific surface area between dry-coated and wet-coated products. The rate reduces the contact surface between the material and the electrolyte, affecting the lithium ion mass transfer process and causing discharge. This affects the performance of capacity and rate.

[0006] Therefore, the coating effect is uniform, and it has an appropriate specific surface area and porosity, and the passivation layer It is extremely important to provide a cathode material that is not only high in energy density but also has good rate performance. be. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention addresses the loss of surface-active lithium in cathode materials due to water washing of traditional wet coatings and The presence of a NiO passivation layer on the surface of the electrode material satisfies the actual demand for cathode material properties. In order to overcome the problem of not being able to add, the positive electrode material of lithium-ion batteries and The objective is to provide a manufacturing method and a lithium-ion battery, and the positive of the lithium-ion battery Ni on the surface and inside of the electrode material 3+ Because the content is similar and the mixed arrangement nickel content is low, Avoid generating a NiO passivation layer in the cathode material and reduce the loss of surface-activated lithium. This can reduce the phenomenon, and as a result, lithium-ion batteries containing this positive electrode material are improved. It has excellent capacity, rate performance, and cycle performance. [Means for solving the problem]

[0008] To achieve the above objective, a first aspect of the present invention relates to a positive electrode material for a lithium-ion battery. The surface Ni of the positive electrode material is provided. 3+ Content and the internal Ni of the positive electrode material 3+ Ratio of content The ratio is 0.95-1:1, In the aforementioned cathode material, the content of mixed-arranged nickel is 3% or less.

[0009] A second aspect of the present invention provides a method for manufacturing a positive electrode material for a lithium-ion battery, and the The method is, After mixing S1, the cathode material precursor, lithium source and dopant as needed, the first Primary sintering is performed in an oxygen-containing atmosphere, followed by cooling, pulverization, and sieving to obtain the primary sintered material. The steps, S2. After mixing the primary sintering material and the coating agent, secondary sintering is performed in a second oxygen-containing atmosphere. The process includes the steps of performing a sieve, removing iron, and obtaining a lithium-ion battery cathode material. , The oxygen concentration in the second oxygen-containing atmosphere is 90 vol% or higher.

[0010] A third aspect of the present invention provides a positive electrode material for a lithium-ion battery manufactured by the above method. To provide.

[0011] A fourth aspect of the present invention is a lithium-ion battery comprising the positive electrode material of the lithium-ion battery described above. To provide.

[0012] The above technical solution provides a positive electrode material for a lithium-ion battery and a method for manufacturing the same according to the present invention. By method, lithium-ion batteries obtain the following beneficial effects.

[0013] Ni on the surface and inside of the lithium ion cathode material according to the present invention 3+ The content is close, and it is mixed. Due to the low nickel content in the array, a NiO passivation layer is generated in the positive electrode material. This can be avoided and the phenomenon of surface-active lithium loss can be reduced, thereby the positive electrode material The included lithium-ion batteries have improved capacity, rate performance, and cycle performance.

[0014] Furthermore, the positive electrode material of the lithium-ion battery according to the present invention has a specific porosity, and the positive electrode material Even when the surface has a coating layer, the surface can still maintain a loosely porous structure, and the coating layer The material surface is in uniform contact with the reaction site, there are many reaction sites, and there is no localized concentration on the surface of the coating layer. This indicates that the impedance of the positive electrode material is reduced, and lithium iodine containing the positive electrode material is reduced. This helps improve the cycle performance of batteries. Furthermore, this specific porosity is used when the material undergoes electrolysis. It is advantageous for the battery to be thoroughly immersed in the liquid, resulting in higher initial charge-discharge efficiency and rate performance.

[0015] Furthermore, the material has a specific porosity distribution; specifically, the core of the cathode material has low porosity. The shell has high porosity, while the dense structure of the low-porosity core contributes to improving the crack strength of the cathode material. In addition, a shell with high porosity can ensure both a coating effect and an electrolyte penetration effect. The shell is prone to developing microcracks and powdering phenomena during the charge and discharge process, and large air bubbles in the shell Porosity provides space for the expansion and contraction of the unit cell volume during the charge and discharge process, and stress This releases the positive electrode material and improves the cycle life of the lithium-ion battery containing it.

[0016] Furthermore, the primary particles of the positive electrode material of the lithium-ion battery according to the present invention have a specific arrangement state. By combining doping, the arrangement of primary particles in the material is adjusted, and the number of primary particles is reduced. Even if they are arranged radially in the shell part (different doping can also be extended to the core), This is because the orderly arrangement of crystal grains with different crystal plane orientations causes expansion and contraction in different directions. The lithium ion containing the positive electrode material effectively mitigates the pressure and cracking caused by shrinkage. This can improve the battery's cycle performance.

[0017] Furthermore, the cathode material of the lithium-ion battery according to the present invention has an appropriate grain boundary density, and this method Combined doping allows the core-shell structure of the material to have different grain boundary densities. Adjust. In the shell layer, the number of times lithium is absorbed and released from primary particles is high and the electrolyte is high. It comes into contact with the surface for minutes, making it prone to forming microcracks during the cycle, which then develop and the surface can become powdery. Therefore, a low grain boundary density can reduce the formation and development of microcracks at grain boundaries. In the core, there is relatively little contact between the primary particles and the electrolyte, and a higher interfacial density is achieved with lithium This invention provides channels for on-spreading to achieve higher capacity and better rate performance. Differentiation of grain boundary density in the core-shell structure of cathode materials enables high capacity and long cycles of materials. This makes it possible.

[0018] In the method for manufacturing the positive electrode material of a lithium-ion battery according to the present invention, a high oxygen concentration content is In an atmospheric environment, dry coating removes the surface layer of high-nickel ternary materials from the conventional water-washing process. Avoiding contact with water and the formation of an inactive passivation layer due to delithiation, and the surface and bulk phase While maintaining the same internal structure and trivalent activated nickel content to the maximum extent, furthermore, higher capacity and It provides low electrochemical impedance.

[0019] Furthermore, by selecting a specific combination of dopants and combining them with a dry coating, , to manufacture porous secondary particles having a core-shell structure composed of primary particles arranged in an orderly manner. As a result, the positive electrode material has high particle strength, and when used in lithium-ion batteries... In addition, it significantly improves the specific capacity, cycle performance, and rate performance of lithium-ion batteries. Sometimes, this extends the cycle life.

[0020] Furthermore, in the method for manufacturing the positive electrode material of a lithium-ion battery according to the present invention, combination The specific surface area of ​​the primary sintered material is adjusted and controlled by doping. As a result, the surface of the obtained positive electrode material and the electrolyte are sufficiently permeated, and the positive electrode material No excess surface lithium remains on the surface, and the primary sintered material is obtained after dry coating. The resulting positive electrode material can exhibit high discharge capacity. [Brief explanation of the drawing]

[0021] [Figure 1] This is a cross-sectional SEM view of the cathode material obtained in Example 1. [Figure 2] This is a surface SEM image of the cathode material obtained in Example 1. [Figure 3] This is a cross-sectional SEM view of the cathode material obtained in Example 9. [Figure 4] This is a surface SEM image of the cathode material obtained in Example 9. [Figure 5] This is a cross-sectional SEM view of the cathode material obtained in Example 10. [Figure 6] This is a surface SEM image of the cathode material obtained in Example 10. [Figure 7] This is a cross-sectional SEM view of the cathode material obtained in Example 2. [Figure 8] This is a surface SEM image of the cathode material obtained in Example 2. [Figure 9] This is a cross-sectional SEM view of the cathode material obtained in Example 3. [Figure 10] This is a surface SEM image of the cathode material obtained in Example 3. [Figure 11] This is a cross-sectional SEM view of the cathode material obtained in Example 4. [Figure 12] This is a surface SEM image of the cathode material obtained in Example 4. [Figure 13] This is a comparison chart of the initial discharge capacities of Example 1, Example 9, Comparative Example 1, and Comparative Example 3. [Figure 14] This is a dQ / dV comparison chart for Example 1, Example 9, Comparative Example 1, and Comparative Example 3. [Figure 15] This is a comparison chart of the rate performance of Examples 1-3, 9, and 10. [Figure 16] This is a comparison chart of the cycle performance of Examples 1-3, 9, and 10. [Modes for carrying out the invention]

[0022] To achieve the above effects, the first aspect of the present invention provides a positive electrode material for a lithium-ion battery, where the ratio of the Ni content on the surface of the positive electrode material to the Ni content inside the positive electrode material is 3+ 0.95 - 1:1, 3+ and in the positive electrode material, the content of the mixed arrangement nickel is 3% or less. In the present invention, the content of the mixed arrangement nickel refers to the ratio of Ni generated by the lithium nickel mixed arrangement to the total Ni, which can be measured by XRD finishing.

[0023] 2+

[0024] In the present invention, the surface Ni content and the internal Ni content of the positive electrode material are measured by XPS. The surface Ni content of the positive electrode material is the result of directly testing the finished product sample by XPS, and the internal Ni content is the result of testing the finished product sample after pulverizing it into primary particles by an air flow mill and then etching it by 30 nm and then performing XPS testing. 3+ 3+ <> 3+ 3+

[0025] In the case of a layered ternary positive electrode material, such as a nickel cobalt manganese ternary positive electrode material, Ni, Co, and Mn are located in the transition metal layer of the lattice, and the theoretical valence of active Ni is +3. In actual production, Ni and Ni 2+ coexist in the lattice, and the Ni 3+ part is free in the interlayer and occluded in the reversible Li layer, 2+ resulting in the generation of a lithium nickel mixed arrangement, which affects the capacity and cycle life of the lithium-ion battery manufactured from the positive electrode material. In the manufacturing process of traditional positive electrode materials, in the water washing process, due to the contact between the surface of the positive electrode material and water, a large amount of lithium is removed from the surface of the positive electrode material. <) ​​​​​​​​​​​​Umm, and finally NiOOH is formed, and NiOOH is deoxygenated during the subsequent heating process and becomes non-oxidized. An electrochemical rock salt phase NiO passivation layer was generated, and according to XPS detection, the cathode material Ni on the surface 3+ The content has decreased significantly, Ni 2+ The content is improved, and ultimately the positive electrode material We discovered that the electrochemical performance of lithium-ion batteries manufactured from deteriorates, and specifically, Battery capacity decreases, and impedance and polarization increase significantly.

[0026] According to research, the inventors of this invention have found that the surface and interior of the positive electrode material of lithium-ion batteries contain Ni 3+ Having a content close to and low mixed arrangement nickel content, specifically limited in the present invention By controlling it to satisfy the range, a NiO passivation layer is added to the cathode material. To avoid generation, reduce the phenomenon of surface-active lithium loss, and reduce lithium ions containing the cathode material The battery has improved capacity, rate performance, and cycle performance.

[0027] Furthermore, the surface Ni of the positive electrode material 3+ Content and the internal Ni of the positive electrode material 3+ Ratio of content The ratio is 0.97-0.99:1, In the aforementioned cathode material, the content of mixed-arranged nickel is 1.5% or less.

[0028] According to the present invention, the positive electrode material is Ni 3+ Content and Ni 2+ The ratio to the content is 2 or more. That is the case.

[0029] In the present invention, Ni in the positive electrode material 3+ Content and Ni 2+ The ratio of the content must satisfy the above range. In total, the cathode material has higher activity and fewer lattice defects, and the electrochemical activity of the cathode material This can be significantly improved, and when used in lithium-ion batteries, the battery capacity and Rate performance can be significantly improved, and at the same time, the divalent nickel in the cathode material is A lower amount means less mixed nickel, reducing the risk of lithium-nickel mixed arrays. This improves the structural stability of the positive electrode material and extends the cycle life of the positive electrode material in batteries.

[0030] In the present invention, the positive electrode material is Ni 3+ Content and Ni 2+ The content was measured by XPS. ru.

[0031] Furthermore, in the positive electrode material, Ni 3+ Content and Ni 2+ The ratio of the content is 3-8.

[0032] According to the present invention, the specific surface area S0 of the positive electrode material is 0.1-0.5 m². 2 It is / g.

[0033] In the present invention, the positive electrode material of the lithium-ion battery has a specific specific surface area, and the positive electrode material At the same time, ensure that the surface is sufficiently immersed in the electrolyte, while also ensuring that there is a low residual lithium on the surface of the positive electrode material. It is possible to ensure that the content is sufficient, and lithium-ion batteries containing this positive electrode material have high emission To provide electrical capacity.

[0034] Furthermore, the specific surface area S0 of the positive electrode material is 0.1-0.45 m². 2 It is / g.

[0035] According to the present invention, after being crushed at a pressure of 3.5T, the specific surface area of ​​the positive electrode material is S 3.5 in Yes, the rate of change of specific surface area SSA = (S 3.5 -S0) / S0×100% is 0-50% ru.

[0036] In the present invention, the specific surface area of ​​the positive electrode material before and after cracking at a pressure of 3.5T is within the above range. When the conditions are met, the positive electrode material has certain pressure resistance characteristics. The tear strength is high, and the material is manufactured during the electrode piece manufacturing process. To avoid the risk of bulb breakage during the compaction of the electrode pieces of the material, and to ensure the safety of lithium-ion batteries containing the positive electrode material. While improving stability, the cathode material can withstand higher compaction densities and provide higher energy —It can possess the potential for density.

[0037] Furthermore, (S 3.5 -S0) / S0×100% is 20-50%, preferably 30 It is -45%.

[0038] According to the present invention, the particle size corresponding to 10% of the volume distribution obtained by particle size testing of the cathode material is D 10 0 The material was then crushed under a pressure of 3.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 10% of the volume distribution is D. 10 3.5 And, Here, (D 10 0 -D 10 3.5 ) / D 10 0 ×100% is 0-30%. Furthermore, (D 10 0 -D 10 1 ) / D 10 0 ×100% is 0-20%.

[0039] According to the present invention, the particle size corresponding to 50% of the volume distribution obtained by particle size testing of the cathode material is D 50 0 The material was then crushed under a pressure of 3.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 50% of the volume distribution is D. 503.5 And, Here, (D 50 0 -D 50 3.5 ) / D 50 0 ×100% is 0-15%. Furthermore, (D 50 0 -D 50 3.5 ) / D 50 0 ×100% is equal to 0-10%.

[0040] According to the present invention, the particle size corresponding to 90% of the volume distribution obtained by particle size testing of the cathode material is D 90 0 The material was then crushed under a pressure of 3.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 90% of the volume distribution is D. 90 3.5 And, Here, (D 90 0 -D 90 3.5 ) / D 90 0 ×100% is 0-8%. Furthermore, (D 90 0 -D 90 3.5 ) / D 90 0 ×100% is 0-7%.

[0041] In the present invention, the D of the positive electrode material before and after cracking under a pressure of 3.5T 10 , D 50 and D 90 If at least one of the above ranges is met, the positive electrode material has pressure resistance characteristics, High pressure generates tiny pressure-cracked fine particles, which contributes to the top-level manufacturing process of cathode materials. This demonstrates that safety and stability can be enhanced.

[0042] In the present invention, the particle size corresponding to 10% of the volume distribution obtained by the particle size test of the positive electrode material is D 10 0 After being cracked under a pressure of 2.5 T, the particle size corresponding to 10% of the volume distribution obtained by the particle size test of the multi-component positive electrode material is D After being cracked under a pressure of 2.5 T, the particle size corresponding to 10% of the volume distribution obtained by the particle size test of the multi-component positive electrode material is D 10 2.5 That is, where (D 10 0 - D 10 2.5 ) / D 10 0 × 100% is 0 - 10%, preferably preferably, (D 10 0 - D 10 2.5 ) / D 10 0 × 100% is 0 - 6%.

[0043] In the present invention, the particle size corresponding to 50% of the volume distribution obtained by the particle size test of the positive electrode material is D 50 0 After being cracked under a pressure of 2.5 T, the particle size corresponding to 50% of the volume distribution obtained by the particle size test of the multi-component positive electrode material is D After being cracked under a pressure of 2.5 T, the particle size corresponding to 50% of the volume distribution obtained by the particle size test of the multi-component positive electrode material is D 50 2.5 That is, where (D 50 0 - D 50 2.5 ) / D 50 0 × 100% is 0 - 6%, preferably preferably, (D 50 0 - D 50 2.5 ) / D 50 0 × 100% is 0 - 5%.

[0044] In the present invention, the particle size corresponding to 90% of the volume distribution obtained by the particle size test of the positive electrode material is D 90 0The material was then crushed under a pressure of 2.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 90% of the volume distribution is D. 90 2.5 And, Here, (D 90 0 -D 90 2.5 ) / D 90 0 ×100% is 0-4%, which is preferable. (D 90 0 -D 90 2.5 ) / D 90 0 ×100% is 0-3%.

[0045] In the present invention, the particle size corresponding to 10% of the volume distribution obtained by particle size testing of the cathode material is D 10 0 The material was then crushed under a pressure of 4.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 10% of the volume distribution is D. 10 4.5 And, Here, (D 10 0 -D 10 4.5 ) / D 10 0 ×100% is 0-50%, which is preferred. Or, (D 10 0 -D 10 4.5 ) / D 10 0 ×100% is 0-40%.

[0046] In the present invention, the particle size corresponding to 50% of the volume distribution obtained by particle size testing of the cathode material is D 50 0 The material was then crushed under a pressure of 4.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 50% of the volume distribution is D. 50 4.5 And, Here, (D 50 0 -D 50 4.5 ) / D 50 0 ×100% is 0-30%, which is preferred. Or, (D 50 0 -D 50 4.5 ) / D 50 0 ×100% is 0-20%.

[0047] In the present invention, the particle size corresponding to 90% of the volume distribution obtained by particle size testing of the cathode material is D 90 0 The material was then crushed under a pressure of 4.5T, and the particle size of the multi-component cathode material was determined by a particle size test. The particle size corresponding to 90% of the volume distribution is D. 90 4.5 And, Here, (D 90 0 -D 90 4.5 ) / D 90 0 ×100% is 0-15%, which is preferred. Or, (D 90 0 -D 90 4.5 ) / D 90 0 ×100% is equal to 0-10%.

[0048] According to the present invention, the porosity of the cathode material is 1-8%.

[0049] In the present invention, the positive electrode material of the lithium-ion battery has a specific porosity, and in particular pores Because it has a rate distribution, it extends the cycle life of lithium-ion batteries containing the positive electrode material. It is possible.

[0050] In this invention, porosity is determined using multiple cross-sectional SEM images and software statistical methods. It was measured.

[0051] Furthermore, the porosity of the cathode material is 2-7%, preferably 3-6%.

[0052] According to the present invention, the positive electrode material is a secondary particle having a core-shell structure.

[0053] According to the present invention, the porosity of the core of the cathode material is 0.1-2%.

[0054] According to the present invention, the porosity of the shell of the cathode material is 3-8%.

[0055] In the present invention, the positive electrode material of the lithium-ion battery has a specific porosity, and in particular, The core of the polar material has low porosity, while the shell has high porosity and low porosity. The dense structure of the core contributes to improving the crack strength of the cathode material, and the shell with high porosity This can provide space for the expansion and contraction of the unit cell volume during the charging and discharging process, This relieves stress and extends the cycle life of the lithium-ion battery containing the positive electrode material.

[0056] Furthermore, the porosity of the core in the aforementioned cathode material is 0.13-2%.

[0057] Furthermore, the porosity of the shell in the aforementioned cathode material is 4-7%.

[0058] According to the present invention, in the positive electrode material, the ratio of the radii of the core to the shell layer is 0.5-9:1. ru.

[0059] In the present invention, if the ratio of the radius of the core to the shell layer in the positive electrode material satisfies the above range, the material This not only ensures that the outer layer has a certain porosity, but the material also has a certain cracking rate. It is also possible to ensure that it has strength, and when used in lithium-ion batteries, Mu-ion batteries offer superior overall performance, such as high capacity, excellent cycle life, and excellent stability. To possess.

[0060] Furthermore, in the aforementioned cathode material, the ratio of the core to shell layer radii is 0.5-3:1.

[0061] According to the present invention, in the positive electrode material, the aspect ratio of the primary particles of the core is 1-2:1. ru.

[0062] According to the present invention, in the cathode material, the aspect ratio of the primary particles of the shell layer is 3-7:1 That is the case.

[0063] In the present invention, the aspect ratio of the primary particles of the core in the positive electrode material or the primary particles of the shell layer If at least one of the aspect ratios of the child satisfies the above range, the core of the positive electrode material is oblate. It is a structure in which primary particles with a small aspect ratio are deposited, and the primary particles are tightly packed together in a disordered manner. It deposits to form a dense structure with low porosity and high grain boundary density. The shell layer is elongated. Relatively large primary particles are arranged radially, and the contact surfaces between primary particles are relative. There are few particles, and many holes are formed between them, resulting in a relatively sparse structure that is stacked, and at the same time, The primary particles of the positive electrode material have an appropriate arrangement orientation, and release the stress generated during the charge-discharge process, This prevents the formation of microcracks between particle interfaces, ultimately extending the cycle life of the cathode material. It can be done.

[0064] Furthermore, in the aforementioned cathode material, the aspect ratio of the primary particles of the core is 1.2-1.8:1. ru.

[0065] Furthermore, in the aforementioned cathode material, the aspect ratio of the primary particles in the shell layer is 3-6:1.

[0066] According to the present invention, the aspect ratio of the primary particles of the positive electrode material is 1-6:1.

[0067] Furthermore, the aspect ratio of the primary particles of the positive electrode material is 1-5:1.

[0068] According to this application, the positive electrode material comprises a matrix and a coating applied to the matrix. Including layers, The matrix has the configuration shown in formula I, and the coating layer is a lithium oxygenated material containing element J. Contains compounds and / or oxides containing element J, Li 1+a1 (Ni x Co y Mn z M m )O2 formula I Here, -0.1 ≤ a1 ≤ 0.2, 0 <x<1、0≦y≦0.4、0<z≦0.6、0 ≤ m ≤ 0.1, where M is Ta, Cr, Mo, W, Al, Y, Ti, Zr, V, Nb, At least one of Ca, P, Co, Ce, Er, Mg, B, Sr, Ba, and La J is selected from among Zr, V, B, Al, Sr, Co, W, Mo and Mn, and is at least One will be chosen.

[0069] In the present invention, the positive electrode material is made from lithium oxygen compounds and / or oxides of a specific element. It includes a coating layer in which the specific element is bonded to or attached to the surface of the positive electrode material, and on the surface of the positive electrode material It forms a protective layer, reduces side reactions between the material and the electrolyte, and to some extent reduces the phenomenon of material pulverization. This improves the cycle stability of lithium-ion batteries containing the positive electrode material.

[0070] In the present invention, the lithium oxygen compound and / or oxide containing element J are , potentially containing at least one element from the matrix: Ni, Co, Mn, M There are also others.

[0071] In one specific embodiment of the present invention, preferably -0.1 ≤ a1 ≤ 0.15, 0 < x < 0.99, 0 <y≦0.3、0<z≦0.4、0<m≦0.05であり、Mは、Ti , at least one of B, La, P and W and Al, Nb, Cr, V, M as needed From at least one of g, Sr, Y, Ce, Ca, V, Ta, Co, Zr, and Mo Selected, J is at least one of Zr, V, B, Al, Sr, Co, W, Mo, and Mn One will be chosen.

[0072] In the present invention, if the positive electrode material contains a specific type of element M, the primary grains of the positive electrode material The dominant growth in the dominant direction of the particle is promoted, the primary particle exhibits a more elongated structure, and there are many particles between the particles. Numerous pores are formed, increasing the overall porosity of the material. Specific pore structures are found in dry coatings. In addition to providing more storage and reaction space in the coating layer, the material is thoroughly absorbed by the electrolyte. It is absorbed into the water, which helps to achieve higher initial charge / discharge efficiency and rate performance.

[0073] According to the present invention, the element J in the coating layer is 0.05 wt% - 1.5 wt% of the total mass of the positive electrode material. It accounts for %.

[0074] In the present invention, the content of element J in the coating layer of the positive electrode material satisfies the above range. The coating layer protects and modifies the surface of the positive electrode material to a certain extent, but if it is too thick, it interferes with the conductivity of the positive electrode material. This prevents interference with the gram capacity.

[0075] Furthermore, element J in the coating layer accounts for 0.05 wt% to 1 wt% of the total mass of the positive electrode material.

[0076] According to the present invention, in the cathode material, surface-free Li is 3%-6% of the total Li element molar ratio. It occupies the majority.

[0077] In this invention, surface-free Li refers to lithium carbonate and lithium hydroxide on the surface of the positive electrode material. This is the total lithium content, measured by potentiometric titration using a 905 potentiometric titrator.

[0078] When the surface-free Li content in the cathode material meets the above range, it indicates effective active lithium content. It provides quantity, reduces the risk of lithium deficiency in the material lattice, and enables the material to exhibit high capacity. In addition to securing it, too much surface-free lithium increases the material impedance, and This can prevent serious storage gas production.

[0079] Furthermore, in the aforementioned cathode material, surface-free Li accounts for 3.5%-5% of the total Li element molar ratio. Mel.

[0080] According to the present invention, the moisture content of the positive electrode material is 0-100 ppm.

[0081] In the present invention, when the moisture content of the positive electrode material satisfies the above range, the positive electrode material has fewer crystals. It contains water and adsorbed water, exhibits few side reactions with water, and has high electrochemical activity. When used in lithium-ion batteries, these batteries exhibit excellent cycle stability.

[0082] In this invention, the moisture content of the cathode material was measured using a precision moisture meter.

[0083] Furthermore, the moisture content of the positive electrode material is 0-80 ppm.

[0084] A second aspect of the present invention provides a method for manufacturing a positive electrode material for a lithium-ion battery, and the The method is, S1. After mixing a cathode material precursor, a lithium source, and a dopant if necessary, perform primary sintering in a first oxygen-containing atmosphere, cool, pulverize, and screen to obtain a primary sintered material . S2. After mixing the primary sintered material and a coating agent, perform secondary sintering in a second oxygen-containing atmosphere , screen, remove iron, and obtain a cathode material for a lithium-ion battery. . The oxygen concentration in the second oxygen-containing atmosphere is 90 vol% or more.

[0085] In the present invention, in a method for manufacturing a cathode material for a lithium-ion battery, in an atmosphere containing a high oxygen concentration , by dry coating, the contact between the surface of a high-nickel ternary material and water and the formation of an inactive passivation layer due to delithiation in the conventional water washing process are avoided, and the same structure and the trivalent active nickel content in the surface and the bulk phases are maximally retained. Specifically, the cathode material for a lithium-ion battery described in the first aspect of the present invention is manufactured, and the cathode material has a lower electrochemical impedance. When it is used in a lithium-ion battery, the capacity, rate performance, and cycle performance of the lithium-ion battery can be effectively improved.

[0086] Furthermore, the oxygen concentration in the second oxygen-containing atmosphere is 98 vol% or more.

[0087] According to the present invention, in step S1, the dopant is a compound containing a doping element M , and M is selected from at least one of Ta, Cr, Mo, W, Al, Y, Ti, Zr, V, Nb, Ca, P, Co , Ce, Er, Mg, B, Sr, Ba, and La.

[0088] According to the present invention, the oxygen concentration in the first oxygen-containing atmosphere is 95 vol% or more. Preferably, the concentration is 98-100 vol%.

[0089] According to the present invention, the conditions for the primary sintering are a heating rate of 2-8°C / min, from room temperature to 6 This includes raising the temperature to 00-900°C and sintering for 8-14 hours.

[0090] In the present invention, when primary sintering is performed under the above conditions, rational melting and transfer of lithium hydroxide occurs. This allows for more time to be allocated, and the solid-phase reactions of lithiumation and doping become more sufficient, and oxygen High concentration also means that nickel cobalt manganese hydroxide is converted from divalent nickel to nickel cobalt. Maximum oxidation of trivalent nickel in lithium tomanganate, resulting in fewer defects and layered electrical properties. It contributes to the formation of chemically active materials.

[0091] Furthermore, the primary sintering conditions were a heating rate of 3-6°C / min, from room temperature to 650-8°C. This includes raising the temperature to 50°C and sintering for 8-12 hours.

[0092] According to the present invention, in step S2, the coating agent is a compound containing coating element J, and J is , selected from at least one of Zr, V, B, Al, Sr, Co, W, Mo, and Mn It can be done.

[0093] According to the present invention, the conditions for secondary sintering are a sintering temperature of 200-600°C and a sintering time of This includes being between 8 and 14 hours.

[0094] In the present invention, when secondary sintering is performed under the above conditions, the coating agent reacts sufficiently with the material substrate. It plays a role in bonding, protecting and modifying the surface of the material, and improving the material's cyclic stability. It is possible. Some coating agents can react with the surface residual alkali under the above conditions, and consume the insulating substance on the surface to improve the discharge capacity and rate performance of the lithium-ion battery including the positive electrode material, while reducing the gas production during the storage and cycling of the material.

[0095] Furthermore, the conditions for the secondary sintering include that the sintering temperature is 300 - 600 °C and the sintering time is 8 - 12 h.

[0096] According to the present invention, in step S1, the addition amount of the lithium source is a stoichiometric ratio of 0.9 ≦ n (Li) / n(Me) ≦ 1.2, preferably 1 ≦ n(Li) / n(Me) ≦ 1.1 and it is added, where n(Me) is the total molar amount of the metal elements in the positive electrode material precursor.

[0097] According to the present invention, in step S1, the addition amount of the dopant is a stoichiometric ratio of 0 ≦ n( M) / n(Me) ≦ 0.1, preferably 0 < n(M) / n(Me) ≦ 0.05 and it is added, where n(Me) is the total molar amount of the metal elements in the positive electrode material precursor.

[0098] According to the present invention, in step S2, the addition amount of the coating agent is added at a mass ratio of 0.05 wt% ≦ m(J) / [m(BM)] ≦ 1.5 wt%, where m(J) is the mass of element J in the coating agent and m(BM) is the mass of the primary sintered material of the positive electrode material.

[0099] Furthermore, in step S2, the addition amount of the coating agent is added at a mass ratio of 0.05 wt% ≦ m(J) / [m(BM)] ≦ 1 wt%.

[0100] In a specific embodiment of the present invention, in step S1, the dopant is the first ​It includes at least one of the Dopant, the Second Dopant, and the Third Dopant, The first dopant is a compound containing doping element M1, where M1 is Al, Nb, or Cr. The second dopant is selected from at least one of V, Mg, and Sr, and is doping It is a compound containing element M2, where M2 is at least one of Ti, B, La, P, and W. Selected from among, the third dopant is a compound containing the doping element M3, where M3 is Y, C It is selected from at least one of e, Ca, V, Ta, Co, Zr, and Mo.

[0101] In the present invention, the first dopant, the second dopant, and the third dopant are different It is used solely to distinguish between different types of dopants and doping elements.

[0102] In the present invention, a specific combination of dopants is selected and bonded to a dry coating, and the first Type M1 dopant is a basic conventional dopant that stabilizes layered oxide structures. The second type of dopant is the primary particle of the micronizing material, which creates a large porosity between the particles. This creates a selection of dopants with sparse secondary particles, and the third type of dopant is arranged in the material. To make it more precise and orderly, and especially to make the arrangement inside the core more precise, the outside is sparse and the inside is A special dopant having a dense core-shell structure is formed. In the present invention, between dopants A porous structure having a core-shell structure composed of primary particles arranged in an orderly manner through a combination of these particles. Secondary particles are manufactured, and the resulting cathode material has high particle strength, and lithium When used in ion batteries, the specific capacity, cycle performance, and rate performance of lithium-ion batteries are Significantly improves performance while simultaneously extending cycle life.

[0103] In one preferred embodiment of the present invention, the dopant is a second dopant and a first dopant It is a combination of a Dopant and / or a third Dopant.

[0104] According to the present invention, in step S1, the amount of the first dopant added is equal to 0 stoichiometric ratio. ≤n(M1) / n(Me)≦0.1, preferably 0≦n(M1) / n(Me)≦0.05 The metal element is added as follows, where n(Me) is the total molar amount of the metal element in the cathode material precursor.

[0105] According to the present invention, in step S1, the amount of the second dopant added is equal to 0 stoichiometric ratio. ≤n(M2) / n(Me)≦0.1, preferably 0≦n(M2) / n(Me)≦0.05 The metal element is added as follows, where n(Me) is the total molar amount of the metal element in the cathode material precursor.

[0106] According to the present invention, in step S1, the amount of the third dopant added is equal to 0 stoichiometric ratio. ≤n(M3) / n(Me)≦0.1, preferably 0≦n(M3) / n(Me)≦0.05 The metal element is added as follows, where n(Me) is the total molar amount of the metal element in the cathode material precursor.

[0107] In one specific embodiment of the present invention, the specific surface area of ​​the primary sintered material is 0.3-0.8 m 2 It is / g.

[0108] In the present invention, if the primary sintered material has a specific surface area within the above range, the surface of the primary sintered material The material has a porous and sparse structure, and when the coating is applied to the primary sintered material, the coating material fills the pores of the primary sintered material. This allows for better penetration, enabling good coating of the primary sintered material, and ultimately yielding The positive electrode material has a low electrochemical impedance, and this positive electrode material is used in lithium-ion batteries. When used, it can significantly improve the discharge capacity and rate performance of lithium-ion batteries. ru.

[0109] Furthermore, the specific surface area of ​​the primary sintered material is 0.35-0.65 m². 2 / g, preferably is 0.35-0.6m 2 It is / g.

[0110] According to the present invention, step S2 corresponds to a volume distribution of 10% determined by the particle size test of the coating agent. The granularity is D 10 Therefore, the particle size corresponding to a volume distribution of 50% is D 50 The volume distribution is 90 The granularity corresponding to % is D 90 And, 1.85≦K 90 =(D 90 -D 10 ) / D 50 It satisfies ≤ 2.83.

[0111] In the present invention, K 90 Select a coating agent that satisfies the above range and dry coat the primary sintered material. This improves the uniformity of the coating, specifically the small particles within the coating agent. It melts more easily and penetrates the pores on the surface of the primary sintered material, providing a larger particle coating within the coating agent. The agent can be uniformly dispersed on the surface of the primary sintered material after it has melted, and finally the coating agent can be applied. The covering effect has been improved.

[0112] In one specific embodiment of the present invention, the coating agent is a compound containing coating element B. D of the coating agent 10 It is 5-15 μm, D 50 It is 30-40 μm, D 90 is 80 It is -90 μm.

[0113] In the present invention, the cathode material precursor employs a conventional cathode material precursor in this field. It is possible, and preferably, the positive electrode material precursor is Prepare a mixed salt solution of nickel salt, cobalt salt, and manganese salt, and then use the mixed salt solution and precipitant solution. The complexing agent solution and the other solution were passed through the reaction vessel, and after coprecipitation in an inert gas environment, the mixture was aged. It can be manufactured by the steps of obtaining the cathode material precursor through washing and drying.

[0114] In this invention, the present invention is not particularly limited to the types of nickel salts, cobalt salts, and manganese salts. Furthermore, conventional nickel salts, cobalt salts, and manganese salts in this field can be used. For example, the nickel salt is nickel sulfate, and the cobalt salt is cobalt sulfate. The manganese salt is manganese sulfate.

[0115] In the present invention, the amounts used of the nickel salt, the cobalt salt, and the manganese salt are n (Ni):n(Co):n(Mn)=x:y:z satisfies 0 <x<1、0<y≦0.4 , 0 <z≦0.6である。

[0116] According to the present invention, the concentration of the mixed salt solution is 1-3 mol / L.

[0117] In the present invention, there are no particular limitations on the type of precipitating agent solution, and conventional methods in the art A precipitating agent solution, such as a sodium hydroxide solution, can be used.

[0118] In the present invention, the type of the complexing agent solution is not particularly limited, and conventional methods in the art A complexing agent solution, such as aqueous ammonia, can be used.

[0119] According to the present invention, the concentration of the precipitating agent solution is 7-10 mol / L.

[0120] According to the present invention, the concentration of the complexing agent solution is 5 mol / L or higher.

[0121] According to the present invention, the conditions for the coprecipitation reaction are a pH of 10.5-11.5 and a stirring speed of At 200-800 rpm, with a reaction temperature of 50-80°C, the flow rate of the mixed salt solution into the reaction vessel is... This includes a flow rate of 100-400 mL / h.

[0122] In the present invention, the pH value during the coprecipitation reaction process, the rate at which the mixed salt solution is introduced into the reaction vessel, By controlling the reaction temperature and stirring rate to satisfy the above range, the primary fibers of the precursor can be produced. It can be grown into an elongated structure, which is arranged radially, and the precursor structure having this structure A layered oxide cathode material that is sparse, has a regular arrangement, is favorable for sufficient lithiumization, and has few defects. To form.

[0123] Furthermore, the conditions for the coprecipitation reaction are a pH of 10.6-11.4 and a stirring speed of 300- The reaction temperature is 55-80°C, preferably 55-75°C, at 700 rpm, and the mixed salt solution is dissolved. This includes a liquid introduction rate of 100-300 mL / h into the reaction vessel.

[0124] A third aspect of the present invention provides a positive electrode material for a lithium-ion battery manufactured by the above method. To provide.

[0125] A fourth aspect of the present invention is characterized by including the above lithium-ion battery positive electrode material. We provide lithium-ion batteries.

[0126] In this invention, unless otherwise specified, room temperature refers to 25°C.

[0127] The present invention will be described in detail below with reference to examples. In the following examples, (1) Morphological test: Scanning electron microscope, model S-4800, manufactured by Hitachi, Ltd. Obtained from the test, (2) Particle size D 10 , D 50 , D 90 Marvern Hydro 2000mu model Obtained from testing of the laser particle size distribution analyzer, (3) Specific surface test: Micromeritics Tristar 3020 model Obtained from the specific surface meter test, (4) XRD finish: Obtained from tests using the Smart Lab9 KW from Nippon Rigakusha, (5) Particle strength test: Test particles obtained using Shimadzu Corporation's microcompression tester MCT-210 and (6) XPS: Perkin Elmer's ESCALAB 250 spec Obtained with a trometer, (7) The surface-free Li content was measured by potentiometric titration using a 905 potentiometric titrator. (8) The matrix composition in the positive electrode material is measured by ICP, (9) The moisture content of the positive electrode material is measured with a precision moisture meter. (10) Electrochemical performance test: In the above examples and comparative examples, the electrochemical performance of the multi-component cathode material is CR20 Tested with 25 button batteries.

[0128] The manufacturing process for the 2025 type button cell battery is as follows:

[0129] Electrode manufacturing: Multicomponent cathode material, acetylene black, and polyvinylidene fluoride (PVDF) Mix ) thoroughly with an appropriate amount of N-methylpyrrolidone (NMP) in a mass ratio of 95:3:2, and equalize. A slurry is formed, the slurry is applied to aluminum foil and dried at 120°C for 12 hours, and then 1 It is press-formed under a pressure of 00 MPa to produce a positive electrode piece with a diameter of 12 mm and a thickness of 120 μm. The load of the multi-component cathode material is 15.5 mg / cm³. 2 That is the case.

[0130] Battery assembly: Fill with argon gas containing less than 5 ppm of both water and oxygen. Inside the gas glove box, the positive electrode piece, separator, negative electrode piece, and electrolyte are 202 After assembling the battery into a Type 5 button cell, let it stand for 6 hours. The negative electrode piece should have a diameter of 17 mm and a thickness of 1 mm. A lithium metal sheet of 1 m is used, and the separator is made of porous polyethylene with a thickness of 25 μm. A film (Celgard 2325) was used, and the electrolyte was 1 mol / L LiPF6. Use an equal mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). do.

[0131] 2025 type button cell battery test: The following examples and comparative examples show that the 2025 type battery was tested by the Shenzhen Xinwei Battery Test System. An electrochemical performance test was conducted on the 0.1C battery, and the charge / discharge current density was 200mA / It is g.

[0132] The charge / discharge voltage range is controlled to 3-4.3V, and button-type batteries are charged and discharged at 0.1C at room temperature. We will perform electrical tests to evaluate the initial charge-discharge ratio capacity and initial charge-discharge efficiency of the multi-component cathode material.

[0133] Cycle performance test: The charge / discharge voltage range was controlled to 3-4.3V, and under a constant temperature of 45°C, the button... The N-type battery was charged and discharged for 2 cycles at 0.1C, then charged and discharged for 80 cycles at 1C, and the multi-phase battery was tested. The high-temperature capacity retention rate of the cathode material is evaluated.

[0134] Rate performance test: Charge / discharge voltage range controlled to 3.0-4.3V, at room temperature, button operated. Charge and discharge the battery for two cycles at 0.1C, then at 0.2C, 0.33C, 0.5C and 1 Each cycle of charging and discharging was performed at C, and the initial discharge ratio capacity at 0.1C and the discharge ratio capacity at 1C were measured. The rate performance of the multi-component cathode material is evaluated by the ratio. The initial discharge ratio capacity at 0.1C is the button. This is the discharge ratio capacity of the first cycle of a button cell battery, and the discharge ratio capacity at 1C is the sixth cycle of a button cell battery. This is the discharge ratio capacity of the Kuru.

[0135] Example 1 (1) Nickel sulfate, cobalt sulfate, and manganese sulfate are n(Ni):n(Co):n (Mn) is dissolved in pure water in a molar ratio of 98:1:1 to create a mixed salt solution A with a concentration of 2.2 mol / L. Then, a sodium hydroxide solution with a concentration of 8 mol / L was prepared as precipitating agent solution B, and a concentration of 6 m was prepared. Prepare a solution of ol / L aqueous ammonia as complexing agent solution C. Add the bottom solution to the reaction vessel to adjust the pH. Adjust to 11, introduce nitrogen gas for protection, control the system temperature to 60°C, and set up solutions A and B and C were added to the reaction vessel through the inlet pipes, and the stirring speed was 500 rpm. The flow rate of combined salt solution A is controlled to 200 mL / h, and the pH of the reaction system is set to 11 ± 0.05. Adjust the flow rates of solutions B and C to stabilize them, until the average particle size D50 in the solution is 14 μm. After growth is complete, the process is aged, separated, washed, and dried to obtain a cathode material precursor.

[0136] (2) The above cathode material precursor, lithium hydroxide, and alumina as the first dopant and oxidation Niobium, boric acid as the second dopant, and yttrium oxide as the third dopant, Molar ratio n(Me):n(Li):n(Al):n(Nb):n(B):n(Y)=1:1 After weighing each of the following quantities: 03, 0, 01, 0, 002, 0, 0, 0, and 0, then uniformly... The mixture is mixed and sintered at a constant temperature in an oxygen furnace with an oxygen concentration of 99%, and the temperature rises from room temperature at a rate of 5°C / min. The temperature is raised to 700°C using a temperature rate, and the sintering time is 12 hours. After cooling, crushing, and sieving, A primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.45 m². 2 It is / g.

[0137] (3) The mass ratio of element B in boric acid I to the primary sintered material is m(B) / [m(BM)] = 0.1 Mix uniformly in a high-speed mixer at 5 wt%, then sinter in an oxygen furnace at a constant temperature of 350°C, and then oxygen The concentration is 99%, and the sintering time is 10 hours. After cooling, sieving, and iron removal, the cathode material is... A1 is obtained, and the composition is Li 1.03 (Ni 0.965 Co 0.01 Mn 0.01 Al 0.0 1Nb 0.002 B 0.001 Y 0.002 ) A matrix which is O2, and the matrix A coating layer containing an oxide of B and / or a lithium oxygen compound of B is applied to the surface of the material. It contains. Element B in the coating layer accounts for 0.15 wt% of the total mass of the positive electrode material.

[0138] Boric acid I D 10 It is 10.2 μm, D 50 It is 32.1 μm, D 90 83 The thickness is 0.3 μm, and the distribution coefficient K 90 It is 2.27.

[0139] Surface Ni of positive electrode material A1 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0140] Figures 1 and 2 show the cross-sectional SEM and surface SEM images of the positive electrode material A1 obtained in Example 1, respectively. Furthermore, the positive electrode material has a core-shell structure, and the core and shell layers have different porosity levels. At the same time, it shows that the primary particles in the shell layer are arranged radially. In cathode material A1, Aspect ratio and porosity of primary particles in the core, aspect ratio and porosity of primary particles in the shell layer, Table 2 shows the aspect ratio and porosity of the primary particles of the cathode material, and the ratio of the core to shell layer radii.

[0141] Example 2 Step (1) is the same as step (1) of Example 1, Step (2) involves a cathode material precursor, lithium hydroxide, and a first dopant, aluminum. Na and niobium oxide, boric acid as the second dopant, and yttriyl oxide as the third dopant. The molar ratio of um is n(Me):n(Li):n(Al):n(Nb):n(B):n(Y). =1:1.03:0.01:0.002:0.001:0.005 After weighing each item separately The mixture is uniformly mixed and sintered at a constant temperature in an oxygen furnace, with an oxygen concentration of 99%, from room temperature to 5°C / mi. The temperature was raised to 700°C at a heating rate of n, and the sintering time was 12 hours. Cooling, crushing, and sieving were performed. Next, a primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.39 m². 2 It is / g.

[0142] Step (3) is the same as in Example 1, to obtain positive electrode material A2, and the composition is Li 1.03 (Ni 0.962 Co 0.01 Mn 0.01 Al 0. Nb 0.002 B 0.001 Y 0.005 ) A matrix which is O2, and an oxide of B and / coated on the surface of the matrix Alternatively, it includes a coating layer containing a lithium oxygen compound of B. The amount of element B in the coating layer is equal to the total mass of the positive electrode material. It accounts for 0.15 wt%.

[0143] Surface Ni of positive electrode material A2 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0144] Figures 7 and 8 show the cross-sectional SEM and surface SEM images of the cathode material A2 manufactured in Example 2, respectively. The positive electrode material has a core-shell structure, and the core and shell layers have different porosities. This simultaneously indicates that the primary particles in the shell layer are arranged radially. Cathode material of Example 1 Compared to material A1, the core and shell layer of cathode material A2 have lower porosity, and the primary grains of the core The arrangement of the particles is denser, and the radial arrangement of primary particles in the shell layer is more regular, and the primary grain The child's aspect ratio is larger.

[0145] In cathode material A2, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0146] Example 3 Step (1) is the same as step (1) of Example 1, Step (2) involves a cathode material precursor, lithium hydroxide, and a first dopant, aluminum. Na, the second dopant is ammonium dihydrogen phosphate, and the third dopant is ammonium oxide. For ttrium, the molar ratio is n(Me):n(Li):n(Al):n(P):n(Y)=1: After weighing each component in the order of 1.03:0.01:0.001:0.002, mix them uniformly and then acid The material was sintered at a constant temperature in a furnace with an oxygen concentration of 99%, and heated from room temperature at a heating rate of 5°C / min to 70°C. The temperature is raised to 0°C and the sintering time is 12 hours. After cooling, crushing, and sieving, the primary sintered material is... The specific surface area of ​​the primary sintered material is 0.41 m². 2 It is / g.

[0147] Step (3) is to manufacture cathode material A3 in the same manner as in Example 1, with a composition of Li 1.03 (Ni 0.967 Co 0.01 Mn 0.01 Al 0.01 P 0.001 Y 0.002 ) O2 A matrix, and an oxide of B and / or a resin of B coated on the surface of the matrix. It contains a coating layer containing a thium oxygen compound. The amount of element B in the coating layer is 0.15 of the total mass of the positive electrode material. It accounts for wt%.

[0148] Surface Ni of positive electrode material A3 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0149] Figures 9 and 10 show the cross-sectional SEM and surface SEM images of the cathode material A3 obtained in Example 3, respectively. As shown, the cathode material has a core-shell structure, and the core and shell layers have different porosities. And at the same time, it shows that the primary particles in the shell layer are arranged radially. Example 1 Compared to cathode material A1, cathode material A3 has a slightly smaller difference in porosity between the core and shell layers, and the core There are also certain pores in that area.

[0150] In cathode material A3, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0151] Example 4 Step (1) is the same as step (1) of Example 1, Step (2) involves a cathode material precursor, lithium hydroxide, and a first dopant, aluminum. First, the second dopant is boric acid, and the third dopant is zirconia, in a molar ratio n(M e):n(Li):n(Al):n(B): n(Zr)=1:1.03:0.01:0 Weigh the 0.001 and 0.002 portions separately, then mix them uniformly according to the conditions of Example 1. Primary sintering is performed to obtain a primary sintered material, and the specific surface area of ​​the primary sintered material is 0.39 m². 2 / g ru.

[0152] Step (3) is to manufacture the positive electrode material A4 in the same manner as in Example 1, and its composition is Li 1.03 (Ni 0.967 Co 0.01 Mn 0.01 Al 0.01 B 0.001 Zr 0.002 ) A matrix which is O2, and an oxide of B and / or which is coated on the surface of the matrix It includes a coating layer containing a lithium oxygen compound of B. The amount of element B in the coating layer is equal to the total mass of the positive electrode material. It accounts for 0.15 wt%.

[0153] Surface Ni of positive electrode material A4 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0154] Figures 11 and 12 show the cross-sectional SEM and surface SEM of the positive electrode material A4 obtained in Example 4, respectively. As shown, the positive electrode material has a core-shell structure, and the core and shell layers have different porosities. At the same time, it shows that the primary particles in the shell layer are arranged radially. Positive electrode of Example 1 Compared to material A1, the porosity of the shell layer of cathode material A4 is slightly lower, and the particle aspect ratio... It is smaller.

[0155] In cathode material A4, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0156] Example 5 (1) Nickel sulfate, cobalt sulfate, and manganese sulfate are n(Ni):n(Co): Mixed salt solution A, prepared by dissolving n(Mn) in pure water in a molar ratio of 82:10:8 to a concentration of 2 mol / L. Obtaining this, prepare a sodium hydroxide solution with a concentration of 8 mol / L as precipitant solution B, and concentrate 5 Prepare 0.4 mol / L aqueous ammonia as complexing agent solution C. Add the bottom liquid to the reaction vessel. The pH was adjusted to 11, nitrogen gas was introduced for protection, and the system temperature was controlled to 60°C. A, B, and C are added to the reaction vessel through the inlet pipes, respectively, and the stirring speed is 500 rpm. The flow rate of mixed salt solution A was controlled to 200 mL / h, and the pH of the reaction system was set to 11 ± 0. Adjust the flow rates of solutions B and C to stabilize at 05, and the average particle size of the particles in the solution D50. After growing to 14 μm, the process is terminated, followed by maturation, separation, washing, and drying to obtain a cathode material precursor.

[0157] (2) Cathode material precursor, lithium hydroxide, alumina as the first dopant, second dopant The dopant is boric acid, and the third dopant is yttrium oxide, in molar ratio n(Me):n( Li):n(Al):n(B):n(Y)=1:1.03:0.01:0.004: 0 Each component was weighed to 0.002, then uniformly mixed, and sintered at a constant temperature in an oxygen furnace with an oxygen concentration of 99%. The temperature was raised from room temperature to 750°C at a heating rate of 5°C / min, and the sintering time was 12 hours. After cooling, crushing, and sieving, a primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0. 35m 2 It is / g. (3) The mass ratio of element B in boric acid I to the primary sintered material is m(B) / [m(BM)] = 0.12 The procedure is almost the same as in step (3) of Example 1, except that the positive electrode material A5 is manufactured in wt%. Composition is Li 1.03 (Ni 0.804 Co 0.1 Mn 0.08 Al 0.01 B 0.004 Y 0.002 ) A matrix which is O2, and B which is coated on the surface of the matrix The device includes a coating layer containing an oxide and / or a lithium oxygen compound of B. The element B in the coating layer is the positive electrode. It accounts for 0.12 wt% of the total mass of the material.

[0158] Surface Ni of positive electrode material A5 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0159] In cathode material A5, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0160] Example 6 (1) Nickel sulfate, cobalt sulfate, and manganese sulfate are n(Ni):n(Co):n (Mn) is dissolved in pure water in a molar ratio of 60:20:20 to form a mixed salt solution with a concentration of 1.6 mol / L. To obtain solution A, prepare a sodium hydroxide solution with a concentration of 8 mol / L as precipitating agent solution B, and concentrate Prepare a 4.8 mol / L aqueous ammonia solution as complexing agent solution C. Add the bottom solution to the reaction vessel. The pH was adjusted to 11, nitrogen gas was introduced for protection, and the system temperature was controlled to 60°C. Solutions A, B, and C were added to the reaction vessel through the inlet pipes, respectively, and the stirring speed was set to 500 rpm. Therefore, the flow rate of mixed salt solution A is controlled to 200 mL / h, and the pH of the reaction system is set to 11± The flow rates of solutions B and C were adjusted to stabilize at 0.05, and the average particle size D50 in the solution was After growing to 14 μm, the process is terminated, followed by maturation, separation, washing, and drying to obtain a cathode material precursor. (2) Cathode material precursor, lithium hydroxide, alumina as the first dopant, second dopant The dopant is boric acid, and the third dopant is yttrium oxide, in molar ratio n(Me):n( Li):n(Al):n(B):n(Y)=1:1.03:0.01:0.005:0. Each component was weighed using 001 and then uniformly mixed, followed by constant-temperature sintering in an oxygen furnace at an oxygen concentration of 99%. Yes, the temperature was raised from room temperature to 850°C at a heating rate of 5°C / min, and the sintering time was 12 hours. After cooling, crushing, and sieving, a primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.3 5m 2 It is / g. (3) The mass ratio of element B in boric acid I to the primary sintered material is m(B) / [m(BM)] = 0.1 A positive electrode material A6 was obtained in wt% and was almost the same as in step (3) of Example 1, with a composition of L i 1.03 (Ni 0.584 Co 0.2 Mn 0.2 Al 0.01 B 0.005 Y 0.00 1) A matrix which is O2, and an oxide of B which is coated on the surface of the matrix and / or includes a coating layer containing a lithium oxygen compound of B. The coating layer is 0.1 of the total mass of the positive electrode material. It accounts for wt%.

[0161] Surface Ni of the cathode material A6 3+ Content, internal Ni 3+ Nickel content, mixed arrangement The quantity, surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0162] In cathode material A6, the aspect ratio and porosity of the primary particles of the core, and the primary particles of the shell layer. Aspect ratio and porosity of the cathode material, aspect ratio and porosity of the primary particles, core and shell layers. The ratio of the radii is shown in Table 2.

[0163] Example 7 Steps (1) and (2) are the same as steps (1) and (2) of Example 1. And, Step (3) involves using boric acid II instead of boric acid I to obtain cathode material A7, and then assembling Nar is Li 1.03 (Ni 0.965 Co 0.01 Mn 0.01 Al 0.01 Nb 0.00 2B 0.001 Y 0.002 ) A matrix which is O2, and on the surface of the matrix The coating layer includes an oxide of B and / or a lithium oxygen compound of B. Element B accounts for 0.15 wt% of the total mass of the positive electrode material.

[0164] D of boric acid II 10 It is 20.1 μm, D 50 It is 43.2 μm, D 90 is 6 The particle size is 7.2 μm, and the distribution coefficient K 90 It is 1.09.

[0165] Surface Ni of positive electrode material A7 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0166] In cathode material A7, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0167] Example 8 Steps (1) and (2) are the same as steps (1) and (2) of Example 1. And, Step (3) uses tungsten oxide instead of boric acid I, and tungsten oxide The W element in the sintered material and the primary sintered material are mixed at a mass ratio of m(W) / [m(BM)] = 0.2 wt%, high speed The mixture is placed in a mixer and uniformly mixed, then sintered at a constant temperature of 460°C in an oxygen furnace with an oxygen concentration of 99%. The sintering time is 10 hours. After cooling, sieving, and iron removal, Li 1.03 (Ni 0.9 65 Co 0.01 Mn 0.01 Al 0.01 Nb 0.002 B 0.001 Y 0.002 ) An O2 matrix, and an oxide of W and / or W coating the surface of the matrix. A coating layer containing a lithium oxygen compound is obtained. The coating layer is 0.20 wt% of the total mass of the positive electrode material. It occupies the majority.

[0168] Distribution coefficient K of tungsten oxide 90 It is 1.51.

[0169] Surface Ni of positive electrode material A8 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0170] In cathode material A8, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0171] In Example 8, tungsten oxide was used as the coating agent, and tungsten oxide was used as the cathode material. It reacts with excess Li on the surface, reducing the surface-free Li content of the positive electrode material, and the positive electrode This material can improve the rate performance and cycle performance of lithium-ion batteries.

[0172] Example 9 Step (1) is the same as step (1) of Example 1, Step (2) involves a cathode material precursor, lithium hydroxide, and a first dopant, aluminum. The molar ratio of sodium and niobium oxide is n(Me):n(Li):n(Al):n(Nb)=1:1. After weighing each component in the ratios 03:0.01:0.002, they are uniformly mixed and then sintered at a constant temperature in an oxygen furnace. The oxygen concentration was 99%, and the temperature was raised from room temperature to 700°C at a heating rate of 5°C / min, and then fired. The sintering time is 12 hours. After cooling, crushing, and sieving, primary sintered material is obtained. Its specific surface area is 0.19 m². 2 It is / g. Step (3) is to manufacture the positive electrode material A9 in the same manner as in Example 1, with a composition of Li 1.03 (Ni 0.968 Co 0.01 Mn 0.01 Al0.01 Nb 0.002 )O2 matrix B oxide and / or lithium oxygen of B coated on the surface of the matrix. It includes a coating layer containing a compound. Element B in the coating layer accounts for 0.15 wt% of the total mass of the positive electrode material. Mel.

[0173] Surface Ni of positive electrode material A9 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0174] Figures 3 and 4 show the cross-sectional SEM and surface SEM images of the positive electrode material A9 obtained in Example 9, respectively. Furthermore, it is shown that the positive electrode material does not have a core-shell structure. In comparison, the aspect ratio of the primary particles of cathode material A9 is smaller, and the particle morphology is more rounded. The primary particles of the core and shell layers are more tightly aligned, and the particles are formed between them. The cavities are small, and the porosity is low.

[0175] In cathode material A9, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0176] Example 10 Step (1) is the same as step (1) of Example 1, Step (2) involves a cathode material precursor, lithium hydroxide, and a first dopant, aluminum. Na, niobium oxide, and the second dopant, boric acid, in a molar ratio n(Me):n(Li):n (Al):n(Nb):n(B)=1:1.03:0.01:0.002:0.001 Each component was weighed and then uniformly mixed, followed by constant-temperature sintering in an oxygen furnace with an oxygen concentration of 99%. The temperature was raised from warm to 700°C at a heating rate of 5°C / min, and the sintering time was 12 hours. Cooling, After crushing and sieving, a primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.48 m². 2 / It is g.

[0177] Step (3) is to manufacture the positive electrode material A10 in the same manner as in Example 1, with a composition of Li 1.03 (N i 0.967 Co 0.01 Mn 0.01 Al 0.01 Nb 0.002 B 0.001 )O2 A matrix, and an oxide of B and / or B coated on the surface of the matrix. It includes a coating layer containing a lithium oxygen compound. The amount of element B in the coating layer is 0. It accounts for 15 wt%.

[0178] Surface Ni of positive electrode material A10 3+ Content, internal Ni 3+ Nickel content, mixed arrangement The quantity, surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0179] Figures 5 and 6 show the cross-sectional SEM and surface SEM of the positive electrode material A10 obtained in Example 10, respectively. As shown, the positive electrode material A10 does not have a core-shell structure, and the entire material has a high porosity. Furthermore, compared to the positive electrode material A1 of Example 1, the primary particles of the positive electrode material A10 are more elongated. The aspect ratio is larger, and the disordered arrangement between primary particles forms many pores. The specific surface area of ​​the secondary particles becomes larger than that.

[0180] In cathode material A10, the aspect ratio and porosity of the primary particles of the core, and the primary particles of the shell layer Aspect ratio and porosity, aspect ratio and porosity of primary particles in cathode material, core and shell layers The ratio of radii is shown in Table 2.

[0181] Example 11 Step (1) is the same as step (1) of Example 1, Step (2) involves the cathode material precursor, lithium hydroxide, and the second dopant, boric acid. Weigh them separately using a molar ratio n(Me):n(Li):n(B)=1:1.03:0.001 After weighing, the mixture was uniformly mixed and sintered at a constant temperature in an oxygen furnace with an oxygen concentration of 99%, starting from room temperature, and 5 The temperature was raised to 700°C at a heating rate of °C / min, and the sintering time was 12 hours. Cooling, crushing, sieving. After separation, a primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.51 m². 2 It is / g. Step (3) is to manufacture the positive electrode material A11 in the same manner as in Example 1, with a composition of Li 1.03 (N i 0.979 Co 0.01 Mn 0.01 B 0.001 ) The matrix is ​​O2, and the preceding The matrix surface is coated with an oxide of B and / or a lithium oxygen compound of B. It includes a coating layer. The element B in the coating layer accounts for 0.15 wt% of the total mass of the positive electrode material. Surface Ni of the cathode material A11 3+ Content, internal Ni 3+ Nickel content, mixed arrangement The quantity, surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0182] In cathode material A11, the aspect ratio and porosity of the primary particles of the core, and the primary particles of the shell layer Aspect ratio and porosity, aspect ratio and porosity of primary particles in cathode material, core and shell layers The ratio of radii is shown in Table 2.

[0183] Example 12 Step (1) is the same as step (1) of Example 1, Step (2) involves the cathode material precursor, lithium hydroxide, and the second dopant, boric acid. , the third dopant yttrium oxide, in molar ratio n(Me):n(Li):n(B):n (Y) = 1:1.03:0.001:0.002 After weighing each component, mix them uniformly. The material was sintered at constant temperature in an oxygen furnace with an oxygen concentration of 99%, starting from room temperature and heated at a rate of 5°C / min for 7°C. The temperature is raised to 0°C and the sintering time is 12 hours. After cooling, crushing, and sieving, the primary sintered material is obtained. The specific surface area of ​​the primary sintered material is 0.47 m². 2 It is / g. Step (3) is to manufacture the positive electrode material A12 in the same manner as in Example 1, with a composition of Li 1.03 (N i 0.977 Co 0.01 Mn 0.01 B 0.001 Y 0.002 )O2 matrix B oxide and / or lithium oxygen of B coated on the surface of the matrix. It includes a coating layer containing a compound. Element B in the coating layer accounts for 0.15 wt% of the total mass of the positive electrode material. Mel.

[0184] Surface Ni of positive electrode material A12 3+ Content, internal Ni 3+ Nickel content, mixed arrangement The quantity, surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0185] In cathode material A12, the aspect ratio and porosity of the primary particles of the core, and the primary particles of the shell layer Aspect ratio and porosity, aspect ratio and porosity of primary particles in cathode material, core and shell layers The ratio of radii is shown in Table 2.

[0186] Comparative Example 1 Steps (1) and (2) are the same as steps (1) and (2) of Example 1. And, Step (3) involves mixing the primary sintering material with water in a solid-liquid ratio of 3:1 and stirring for 2 minutes. After washing with water, the material was compressed, filtered, and dried to obtain the pre-treated material after washing with water. The coating agent was boric acid I The B element in the mixture and this pre-treatment material were added in a mass ratio of m(B) / [m(BM)] = 0.15 wt%. The mixture is then uniformly mixed in a high-speed mixer and sintered at a constant temperature of 350°C in an oxygen furnace, with an oxygen concentration of 99%. The % is , and the sintering time is 10h. After cooling, sieving, and iron removal, the positive electrode material D1 is obtained. , composition is Li 1.03 (Ni 0.965 Co 0.01 Mn 0.01 Al 0.01 Nb 0. 002 B 0.001 Y 0.002 ) A matrix which is O2, and the table of the said matrix The coating includes a coating layer containing an oxide of B and / or a lithium oxygen compound of B that is applied to the surface. The element B in the layer accounts for 0.15 wt% of the total mass of the cathode material.

[0187] Surface Ni of positive electrode material D1 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0188] In cathode material D1, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0189] Comparative Example 2 Steps (1) and (2) are the same as steps (1) and (2) of Example 9. And, Step (3) is the same as in Step (3) of Comparative Example 1 to obtain the positive electrode material D2, and the composition is Li 1.03 (Ni 0.968 Co 0.01 Mn 0.01 Al 0.01 Nb 0.002 )O2 A matrix, and an oxide of B and / or B coated on the surface of the matrix. It includes a coating layer containing a lithium oxygen compound. The amount of element B in the coating layer is 0. It accounts for 15 wt%.

[0190] Surface Ni of positive electrode material D2 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0191] In cathode material D2, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0192] Comparative Example 3 Steps (1) and (2) are the same as steps (1) and (2) of Example 1. And, Step (3) uses an oxide instead of boric acid I, and element W in tungsten oxide. The primary sintered material was then placed in a high-speed mixer at a mass ratio of m(W) / [m(BM)] = 0.2 wt%. The mixture is then uniformly mixed and sintered at a constant temperature of 460°C in an oxygen furnace with an oxygen concentration of 50%. The atmosphere is air. The sintering time is 10 hours. After cooling, sieving, and iron removal, the cathode material is... Material D3 is obtained, and the composition is Li1.03 (Ni 0.965 Co 0.01 Mn 0.01 Al 0. 01 Nb 0.002 B 0.001 Y 0.002 )O 2の Matrix, and the matrix The coating layer includes an oxide of W and / or a lithium oxygen compound of W that is applied to the surface of the material. Furthermore, the W element in the coating layer accounts for 0.2 wt% of the total mass of the positive electrode material.

[0193] Distribution coefficient K of tungsten oxide 90 It is 1.51.

[0194] Surface Ni of positive electrode material D3 3+ Content, internal Ni 3+ Nickel content, mixed arrangement nickel content The surface-free Li content, specific surface area, and moisture content were tested, and the results are shown in Table 1.

[0195] In cathode material D3, the aspect ratio and porosity of the primary particles of the core, and the aspect ratio of the primary particles of the shell layer Spectrum ratio and porosity, aspect ratio and porosity of primary particles in cathode material, and half of the core and shell layers. The ratio of the diameters is shown in Table 2.

[0196] [Table 1-1]

[0197] [Table 1-2]

[0198] [Table 2-1]

[0199] [Table 2-2]

[0200] The positive electrode materials of the examples and comparative examples were pressed under conditions of 2.5T, 3.5T, and 4.5T, respectively. The specific surface area and particle size of the positive electrode material were tested after cracking and crushing, and the specific surface area and particle size before and after crushing were also tested. The rate of change is shown in Table 3.

[0201] [Table 3-1]

[0202] [Table 3-2]

[0203] The positive electrode material was assembled into a 2025 type button cell battery, and the electrochemical performance of the battery was tested. This is shown in Table 4.

[0204] [Table 4]

[0205] As can be seen from Tables 1-4, in Examples 1-10 of the present invention, dry coating is performed simultaneously with, The oxygen concentration in the oxygen-containing atmosphere during the coating process is controlled, and the surface and interior of the resulting positive electrode material are controlled. Ni 3+ The content is made close to that of the mixed arrangement nickel, and the nickel content is low, and the positive electrode material is Ni To avoid the formation of a passivation layer and reduce the loss of surface-active lithium This allows for improved capacity and rate of change in lithium-ion batteries containing the positive electrode material. It possesses performance and cycle performance.

[0206] In Comparative Examples 1-2, a wet coating method was employed, and during the coating process, the primary sintered material was washed with water, and the cathode material The lithium carbonate and activated lithium such as lithium hydroxide on the surface of the material are washed away, and some of the activated lithium Sexual Ni 3+ Ni 4+ It is converted to Ni 2+ It is broken down and converted, and as a result, the surface Ni 3+ The content and internal ratio decrease, the mixed arrangement nickel content increases, and the surface of the cathode material decreases. A NiO passivation layer is formed, and ultimately lithium ions are manufactured from the cathode material. Battery capacity, rate performance, and cycle performance will deteriorate.

[0207] Furthermore, in the cathode materials obtained in Examples 1-8 of the present invention, specific doping elements are selected. By doing so, the positive electrode material forms a specific core-shell structure, and specifically, the core and shell layers are different. It has a porosity and the core contains primary particles with a small aspect ratio, and the shell layer has an aspect ratio It contains large primary particles, and at the same time, the primary particles of the shell layer are arranged radially. The positive electrode material having the above-described specific core-shell structure ensures sufficient contact between the positive electrode material and the electrolyte. In this case, the particle strength of the positive electrode material can be improved, and the primary particles of the shell layer are arranged radially. Furthermore, expansion and contraction occur in different directions in crystal grains with different crystal plane orientations, resulting in compression. This is advantageous for crack mitigation, and a grain boundary density with a low shell layer is beneficial for microcracks at grain boundaries. Reduce generation and development, and improve the charge-discharge cycle performance and usage of lithium-ion batteries containing the cathode material. To improve service life.

[0208] Compared to Examples 1 and 2, the doping ratio of the third doping element is improved. Therefore, the porosity of the core, shell layer, and overall porosity of the cathode material decreases, and the core and shell layer The arrangement of primary particles is denser, and the radial arrangement of primary particles in the shell layer is more regular. The aspect ratio of the primary particles is larger, and the cathode material has a smaller specific surface area. The material has better particle strength, and lithium-ion batteries containing this positive electrode material have better size It has cruiser capabilities.

[0209] As can be seen from Examples 1 and 3-4, cathode materials containing different doping elements are actually This method has a similar structural effect to Example 1 and similarly improves the electrochemical performance of lithium-ion batteries. It is possible.

[0210] As can be seen from Examples 1 and 5-6, the manufacturing method according to the present invention is suitable for different types Applicable to precursor materials, the cathode materials obtained with different types of precursor materials are all lithium This can improve the electrochemical performance of ion batteries.

[0211] As can be seen from Examples 1 and 7, coatings of different particle sizes are preferred in the present invention. Coating agents with a specific particle size distribution can achieve better results.

[0212] As can be seen from Examples 1 and 8, different coating elements are selected, and the dry coating of the present invention The system can coat the base material, has a high trivalent Ni content, and provides an improvement effect. A finished positive electrode material having the following properties is formed.

[0213] Figure 13 is a comparison chart of the initial discharge capacities of Example 1, Example 9, Comparative Example 1, and Comparative Example 3. Figure 14 is a dQ / dV comparison diagram for Example 1, Example 9, Comparative Example 1, and Comparative Example 3, and Figure 13 As can be seen from Figure 14, the charging voltage of the lithium-ion battery containing the positive electrode material of the present invention It has a low charge-discharge polarization, excellent rate performance, and superior initial discharge capacity.

[0214] Figure 15 is a comparison diagram of the rate performance of Examples 1, 9, 10, and 2 and 3. Figure 16 is a comparison diagram of the cycle performance of Examples 1, 9, 10, and 2 and 3. As can be seen from Figures 15 and 16, Examples 9 and 10 do not have a core-shell structure. In comparison, lithium-ion batteries containing cathode materials with a core-shell structure offer superior performance. It possesses both cruise and rate-of-effect capabilities.

[0215] The above describes preferred embodiments of the present invention in detail, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, several simple modifications are possible to the technical solution means of the present invention. These simple variations include combining each technical feature in any other suitable way. The combinations thereof are similarly deemed to be within the scope of the disclosures of this invention, and both fall within the scope of protection of this invention. To belong to.

Claims

1. A positive electrode material for a lithium-ion battery, wherein the surface Ni of the positive electrode material ３＋ Content and the above positive Ni inside the electrode material ３＋ The ratio of the content is 0.95-1:

1. The positive electrode material is characterized in that it contains 3% or less of mixed nickel. The positive electrode material for lithium-ion batteries.

2. The surface Ni of the positive electrode material ３＋ Content and the internal Ni of the positive electrode material ３＋ The ratio of content is 0.9 The ratio is 7 - 0.99:1, In the aforementioned positive electrode material, the content of mixed nickel array is 1.5% or less. Preferably, the positive electrode material is Ni ３＋ Content and Ni ２＋ The ratio of the content is 2 or more. The positive electrode material for a lithium-ion battery according to claim 1, preferably 3-8.

3. The specific surface area S of the positive electrode material ０ is 0.1-0.5m ２ / g, preferably 0.1-0 0.45 m ２ is 0.45 m / g, Preferably, after being crushed at a pressure of 3.5T, the specific surface area of ​​the positive electrode material is S １ And this Here, (S １ -S ０ ) / S ０ ×100% is 0-50%, preferably 20-50%. can be, Preferably, the particle size corresponding to 10% of the volume distribution obtained by particle size testing of the positive electrode material is D １ ０ ０ The volume was determined by a particle size test of the multi-component cathode material after it was crushed under a pressure of 3.5T. The granularity corresponding to 10% of the distribution is D. １０ １ And, Here, (D １０ ０ -D １０ １ ) / D １０ ０ ×100% is 0-30%, preferably The range is 0-20%, Preferably, the particle size corresponding to 50% of the volume distribution obtained by particle size testing of the positive electrode material is D ５ ０ ０ The volume was determined by a particle size test of the multi-component cathode material after it was crushed under a pressure of 3.5T. The granularity corresponding to 50% of the distribution is D. ５０ １ And, Here, (D ５０ ０ -D ５０ １ ) / D ５０ ０ ×100% is 0-15%, preferably The percentage is 0-10%, Preferably, the particle size corresponding to 90% of the volume distribution obtained by particle size testing of the positive electrode material is D ９ ０ ０ The volume was determined by a particle size test of the multi-component cathode material after it was crushed under a pressure of 3.5T. The granularity corresponding to 90% of the distribution is D. ９０ １ And, Here, (D ９０ ０ -D ９０ １ ) / D ９０ ０ ×100% is 0-8%, preferably The range is 0-7%. Preferably, the porosity of the positive electrode material is 1-8%, according to claim 1 or 2. The positive electrode material for um-ion batteries.

4. The cathode material is a secondary particle having a core-shell structure, Preferably, the cathode material has a core porosity of 0.1-2%. Preferably, the positive electrode material has a shell porosity of 3-8%. Preferably, in the positive electrode material, the ratio of the core to shell layer radii is 0.5-9:

1. Preferably, the ratio is 0.5-3:

1. Preferably, in the positive electrode material, the aspect ratio of the primary particles of the core is 1-2:

1. Preferably, in the positive electrode material, the aspect ratio of the primary particles of the shell layer is 3-7:

1. the law of nature, Preferably, the aspect ratio of the primary particles of the positive electrode material is 1-6:1, claim 1- A positive electrode material for a lithium-ion battery as described in any one of item 3.

5. The positive electrode material includes a matrix and a coating layer covering the matrix. The matrix has the configuration shown in formula I, and the coating layer is a lithium oxygen compound containing element J. Includes substances and / or oxides containing element J, Li １＋ａ１ (Ni ｘ Co ｙ Mn ｚ M ｍ )O ２ Formula I Here, -0.1 ≤ a １ ≦0.2, 0<x<1, 0≦y≦0.4, 0<z≦0.6, 0 ≤ m ≤ 0.1, M is Ta, Cr, Mo, W, Al, Y, Ti, Zr, V, Nb, Ca, P, Co, Ce , selected from at least one of Er, Mg, B, Sr, Ba and La, and J is Zr, Selected from at least one of V, B, Al, Sr, Co, W, Mo, and Mn, Preferably, -0.1 ≤ a １ ≦0.15, 0<x<0.99, 0<y≦0.3, 0<z ≤ 0.4, 0 < m ≤ 0.05, and M is at least one of Ti, B, La, P and W. One more, as needed: Al, Nb, Cr, V, Mg, Sr, Y, Ce, Ca, V, Ta, At least one of Co, Zr, and Mo is selected, and J is Zr, V, B, Al, S Selected from at least one of r, Co, W, Mo, and Mn, Preferably, element J in the coating layer is 0.05 wt% to 1.5 wt% of the total mass of the positive electrode material. Preferably, the ri according to any one of claims 1 to 4, which accounts for 0.05 wt% to 1 wt%. The positive electrode material for lithium-ion batteries.

6. In the aforementioned cathode material, surface-free Li accounts for 3%-6% of the total Li element molar ratio. Preferably, the moisture content of the positive electrode material is 0-100 ppm, according to claims 1-5. Either of the lithium-ion battery cathode materials described in item 1.

7. A method for manufacturing a positive electrode material for a lithium-ion battery, wherein the method is: S1, after mixing the cathode material precursor, lithium source and dopant as needed, the first Primary sintering is performed in an oxygen-containing atmosphere, followed by cooling, pulverization, and sieving to obtain the primary sintered material. The steps, S2. After mixing the primary sintering material and the coating agent, secondary sintering is performed in a second oxygen-containing atmosphere. The steps include: performing the process, sieving, removing iron, and then obtaining the positive electrode material for the lithium-ion battery. Including, The oxygen concentration in the second oxygen-containing atmosphere is 90 vol% or higher, characterized in that A method for manufacturing the positive electrode material for lithium-ion batteries.

8. In step S1, the dopant is a compound containing doping element M, where M is Ta , Cr, Mo, W, Al, Y, Ti, Zr, V, Nb, Ca, P, Co, Ce, Er, M Selected from at least one of g, B, Sr, Ba, and La, Preferably, the oxygen concentration in the first oxygen-containing atmosphere is 95 vol% or higher. Preferably, the primary sintering conditions are such that the heating rate is 2-8°C / min, from room temperature to 600°C. Heat to -900°C and sinter for 8-14 hours. Preferably, in step S2, the coating agent is a compound containing coating element J, where J is Z Selected from at least one of r, V, B, Al, Sr, Co, W, Mo, and Mn, Preferably, the conditions for the secondary sintering are a sintering temperature of 200-600°C and a sintering time of 8- The method according to claim 7, wherein the time is 14 hours.

9. In step S1, the amount of lithium source added is such that the stoichiometric ratio 0.9 ≤ n(Li) / n( The amount of metal element added is such that Me) ≤ 1.2, and n(Me) is the total molar amount of the metal element in the positive electrode material precursor. Preferably, in step S1, the amount of dopant added is such that the stoichiometric ratio 0 ≤ n(M) The additive is added when n(Me) ≤ 0.1, where n(Me) is the total molar amount of the metal element in the positive electrode material precursor. can be, Preferably, in step S2, the amount of coating agent added is 0.05 wt% by mass ratio ≤ m( The substance is added at a concentration of J) / [m(BM)] ≤ 1.5 wt%, where m(J) is the mass of element J in the coating agent. The method according to claim 7 or 8, wherein m(BM) is the mass of the primary sintered material of the positive electrode material. 。

10. In step S1, the dopant is a first dopant, a second dopant and a third dopant Includes at least one of the Dopants, Here, the first dopant is doping element M. １ It is a contained compound, M １ Al, N At least one of b, Cr, V, Mg and Sr is selected, and the second dopant is -ping element M ２ It is a contained compound, M ２ at least one of Ti, B, La, P, and W Each is chosen from one, and the third dopant is doping element M ３ It is a contained compound, M ３ teeth , selected from at least one of Y, Ce, Ca, V, Ta, Co, Zr and Mo, Preferably, in step S1, the amount of the first dopant added is such that the stoichiometric ratio is 0 ≤ n (M １ ) / n(Me) ≤ 0.1 is added, where n(Me) is the total amount of metal elements in the cathode material precursor. This is a molar quantity. Preferably, in step S1, the amount of the second dopant added is such that the stoichiometric ratio is 0 ≤ n (M ２ ) / n(Me) ≤ 0.1 is added, where n(Me) is the total amount of metal elements in the cathode material precursor. This is a molar quantity. Preferably, in step S1, the amount of the third dopant added is such that the stoichiometric ratio is 0 ≤ n (M ３ ) / n(Me) ≤ 0.1 is added, where n(Me) is the total amount of metal elements in the cathode material precursor. This is a molar quantity. Preferably, the specific surface area of ​​the primary sintered material is 0.15–0.8 m². ２ / g, Preferably, in step S2, the volume distribution of the coating agent, as determined by the particle size test, corresponds to 10%. D is a particle size １０ D, which is the particle size corresponding to a volume distribution of 50%. ５０ and volume distribution of 90% The corresponding granularity is D ９０ 1.5 ≤ K ９０ = (D ９０ -D １０ ) / D ５０ ≤ 2.8 Fulfill, Preferably, the coating agent is a compound containing coating element B, and the coating agent D １０ 5-15 It is μm, D ５０ It is 30-40 μm, D ９０ The size is 80-90 μm, claim 7 The method described in any one of item -9.

11. The aforementioned cathode material precursor is Prepare a mixed salt solution of nickel salt, cobalt salt, and manganese salt, and then use the mixed salt solution and precipitant solution. The complexing agent solution and the other solution were introduced into the reaction vessel, and after the coprecipitation reaction was carried out with inert gas, It is manufactured by the steps of forming, washing, and drying to obtain the cathode material precursor, Preferably, the concentration of the mixed salt solution is 1-3 mol / L. Preferably, the concentration of the precipitating agent solution is 7-10 mol / L. Preferably, the concentration of the complexing agent solution is 5 mol / L or higher. Preferably, the conditions for the coprecipitation reaction are a pH of 10.5-11.5 and a stirring speed of 20 The reaction speed is 0-800 rpm, the reaction temperature is 50-80°C, and the rate of introduction of the mixed salt solution into the reaction vessel is 1 The method according to any one of claims 7-10, comprising the characteristics of being 00-400 mL / h.

12. Lithium-ion battery manufactured by the method described in any one of claims 7-11 The positive electrode material.

13. A lithium-ion battery positive electrode material according to any one of claims 1-6 and 12, A lithium-ion battery characterized by the following features.

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