Ternary high-nickel cathode material, preparation method thereof, lithium-ion battery and electrical equipment

Abstract

The present application provides a ternary high-nickel cathode material, a preparation method thereof, a lithium-ion battery and an electrical device, relating to the field of lithium-ion batteries. The preparation method of the ternary high-nickel cathode material includes: mixing a cathode material precursor, a lithium source and a zirconium-containing additive, and performing a first sintering to obtain a product after the first sintering; mixing the product after the first sintering with a titanium-containing additive, and performing a second sintering to obtain a product after the second sintering; mixing the product after the second sintering with water and aluminum nitrate, and performing wet washing and coating, filtering and drying to obtain a coated material; mixing the coated material with a doping element-containing additive, and performing a third sintering to obtain the ternary high-nickel cathode material. The present application can form a uniform needle-shaped coating layer on the surface of the product after the second sintering, which can prevent the direct contact between the electrolyte and the material, reduce the occurrence of side reactions, and also avoid the migration of lithium ions to the surface, maintain the structural stability of the material, and is beneficial to the capacity performance.

Description

Technical Field

[0001] The present application relates to the field of lithium-ion batteries, and particularly to a ternary high-nickel cathode material, a preparation method thereof, a lithium-ion battery, and an electrical device. Background Art

[0002] Due to its high specific capacity, high energy density, and environmentally friendly characteristics, the ternary cathode material has become an indispensable portable energy solution in modern life and is playing an increasingly important role in industrial production. With the rapid development of electric vehicles, energy storage systems, and portable electronic devices, the market's requirements for battery performance are constantly increasing, driving the development of ternary cathode materials towards higher nickel content. High nickel content can not only further improve the energy density of the battery but also reduce costs, which is an important way to optimize battery performance.

[0003] However, with the increase in nickel content, the ternary cathode material faces a series of new challenges. The high activity of nickel ions leads to cation mixing, especially the mixing of nickel ions and lithium ions, which not only causes the decline of battery capacity but also significantly reduces the rate performance, cycle performance, and thermal stability of the material. These negative effects greatly shorten the service life of lithium batteries and limit the application of ternary cathode materials in the fields of high-performance and long-life batteries.

[0004] To overcome these challenges, researchers have conducted extensive modification studies on ternary cathode materials. Doping and coating are two main modification methods. However, the traditional dry coating process has the problem of uneven coating, resulting in poor overall coating effect of the material and unable to fully play the protective role of the coating layer.

[0005] Although the wet coating process improves the coating uniformity to a certain extent, the phenomenon of lithium ion migration to the surface is likely to occur during the preparation process, which not only destroys the internal structure of the material but also affects the electrochemical performance of the battery. Summary of the Invention

[0006] The purpose of the present application is to provide a ternary high-nickel cathode material, a preparation method thereof, a lithium-ion battery, and an electrical device to solve the above problems.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] A preparation method of a ternary high-nickel cathode material, comprising:

[0009] Mixing a cathode material precursor, a lithium source, and a zirconium-containing additive, and performing a first sintering to obtain a product after the first sintering;

[0010] Mixing the product after the first sintering with a titanium-containing additive, and performing a second sintering to obtain a product after the second sintering;

[0011] Mix the product after the secondary sintering with water and aluminum nitrate, conduct wet washing and coating, filter and dry to obtain the coated material.

[0012] Mix the coated material with an additive containing a doping element, conduct three - time sintering to obtain a ternary high - nickel cathode material, wherein the doping element includes at least one of B, Mg, Y, and Mo.

[0013] According to an embodiment of the present application, the cathode material precursor includes Ni x Co y Mn z (OH)2, where x≥0.9, y>0, z>0, and x + y + z = 1;

[0014] And / or, the lithium source includes lithium hydroxide;

[0015] And / or, the molar ratio of lithium in the lithium source to the total content of nickel, cobalt, and manganese in the cathode material precursor is 1:(1 - 2);

[0016] And / or, the zirconium - containing additive includes zirconia;

[0017] And / or, the mass of the zirconium - containing additive is 0.1wt% - 0.3wt% of the mass of the cathode material precursor;

[0018] And / or, the sintering atmosphere for the first - time sintering includes oxygen;

[0019] And / or, the heating rate for the first - time sintering is 1 - 5°C / min;

[0020] And / or, the temperature for the first - time sintering is 700 - 1000°C;

[0021] And / or, the time for the first - time sintering is 12 - 14 hours.

[0022] According to an embodiment of the present application, the titanium - containing additive includes at least one of tetra - tert - butyl titanate, alkoxy titanate, and tetrabutyl titanate;

[0023] And / or, the mass of the titanium - containing additive accounts for 0.1wt% - 1wt% of the mass of the product after the first - time sintering;

[0024] And / or, the sintering atmosphere for the second - time sintering includes oxygen;

[0025] And / or, the heating rate for the second - time sintering is 1 - 5°C / min;

[0026] And / or, the temperature for the second - time sintering is 400 - 800°C;

[0027] And / or, the time of the secondary sintering is 9 - 12 hours.

[0028] According to an embodiment of the present application, the mass of aluminum nitrate accounts for 1.2wt% - 2.4wt% of the mass of the product after the secondary sintering.

[0029] According to an embodiment of the present application, the mixing of the product after the secondary sintering with water and aluminum nitrate includes: first mixing the product after the secondary sintering with water, and then adding an aluminum nitrate solution, wherein the aluminum nitrate solution is prepared by mixing aluminum nitrate with water;

[0030] The mass ratio of the product after the secondary sintering to water is 1:(1 - 1.8);

[0031] The mass ratio of the product after the secondary sintering to the aluminum nitrate solution is 1:(2.012 - 2.024);

[0032] The mass fraction of aluminum nitrate in the aluminum nitrate solution is 0.60% - 1.19%.

[0033] According to an embodiment of the present application, the drying is carried out under vacuum conditions, and the drying temperature is 100 - 160°C;

[0034] And / or, the drying time is 2 - 4h.

[0035] According to an embodiment of the present application, the additive containing doped elements includes boric acid;

[0036] And / or, the mass of the additive containing doped elements accounts for 0.05wt% - 0.2wt% of the mass of the material after coating;

[0037] And / or, the sintering atmosphere of the tertiary sintering includes oxygen;

[0038] And / or, the heating rate of the tertiary sintering is 1 - 5°C / min;

[0039] And / or, the temperature of the tertiary sintering is 200 - 400°C;

[0040] And / or, the time of the tertiary sintering is 9 - 12 hours.

[0041] The present application also provides a ternary high-nickel cathode material, which is prepared by the preparation method of the ternary high-nickel cathode material described above.

[0042] The present application also provides a lithium-ion battery, which includes the ternary high-nickel cathode material prepared by the preparation method of the ternary high-nickel cathode material described above or includes the ternary high-nickel cathode material described above.

[0043] The present application also provides an electrical device, which includes the lithium-ion battery described above.

[0044] Compared with the prior art, the beneficial effects of the present application include:

[0045] The present application proposes a preparation method of a ternary high-nickel cathode material. Through wet washing and coating, a uniform needle-like coating layer can be formed on the surface of the product after secondary sintering. This coating layer can not only effectively prevent the direct contact between the electrolyte and the material, reduce the occurrence of side reactions, but also avoid the migration of lithium ions to the surface, thereby maintaining the structural stability of the material and facilitating the capacity performance. Compared with the traditional wet coating process, the method of the present application solves the problem of lithium ion migration; compared with the dry coating process, it greatly improves the uniformity and consistency of the coating. Generally speaking, the cathode material prepared by the present application can avoid the migration of lithium ions to the surface while ensuring the coating uniformity. Moreover, the method of the present application also has the advantage of simple operation, which is conducive to large-scale popularization and application.

[0046] The ternary cathode material prepared by the present application not only has a higher discharge capacity performance, but also maintains a lower residual alkali content, thereby improving the battery performance while extending the service life of the battery. Description of the Drawings

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope of the present application.

[0048] Figure 1 It is the SEM image of the material after primary sintering and pulverization in Example 2;

[0049] Figure 2 It is the SEM image of the material with a needle-like surface coating layer after wet washing and coating in Example 2;

[0050] Figure 3 It is the SEM image of the material with a needle-like surface coating layer after wet washing and coating in Example 2 at different magnification ratios;

[0051] Figure 4 It is the coating element distribution map of the material with a needle-like surface coating layer after wet washing and coating in Example 2;

[0052] Figure 5 It is the SEM image of the ternary high-nickel cathode material prepared in Example 2. Detailed Embodiments

[0053] As used herein, the terms:

[0054] "Prepared from" is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or apparatus comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or apparatus.

[0055] The conjunctive "consisting of" excludes any unrecited element, step or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0056] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, whether or not the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0057] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0058] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass part of component A is a parts and the mass part of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0059] "And / or" is used to indicate that either or both of the stated circumstances may occur. For example, A and / or B includes (A and B) and (A or B).

[0060] To better illustrate the technical solutions provided by this application, before the examples, a general statement of the technical solutions is given as follows:

[0061] A preparation method of a ternary high-nickel cathode material, comprising:

[0062] Mixing a cathode material precursor, a lithium source, and a zirconium-containing additive, and performing a first sintering to obtain a product after the first sintering;

[0063] Mixing the product after the first sintering with a titanium-containing additive, and performing a second sintering to obtain a product after the second sintering;

[0064] Mixing the product after the second sintering with water and aluminum nitrate, performing wet washing and coating, filtering, and drying to obtain a coated material;

[0065] Mixing the coated material with a doping element-containing additive, and performing a third sintering to obtain a ternary high-nickel cathode material, wherein the doping element includes at least one of B, Mg, Y, and Mo.

[0066] In this application, through wet washing and coating, the excess residual alkali on the material surface can be effectively removed, the processing performance of the material can be improved, and an aluminum nitrate coating layer can be formed, which can effectively improve the performance of the cathode material.

[0067] According to an embodiment of this application, the cathode material precursor includes Ni x Co y Mn z (OH)2, where x≥0.9, y>0, z>0, and x + y + z = 1; for example, x can be 0.9, y can be 0.06, and z can be 0.04.

[0068] The cathode material precursor includes but is not limited to Ni 0.9 Co 0.06 Mn 0.04 (OH)2.

[0069] And / or, the lithium source includes lithium hydroxide;

[0070] And / or, the molar ratio of lithium in the lithium source to the total content of nickel, cobalt, and manganese in the cathode material precursor is 1:(1 - 2);

[0071] For example, the molar ratio of lithium in the lithium source to the total content of nickel, cobalt, and manganese in the cathode material precursor can be 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, 1:1.45, 1:1.5, 1:1.55, 1:1.6, 1:1.65, 1:1.7, 1:1.75, 1:1.8, 1:1.85, 1:1.9, 1:1.95, 1:2, or any value between 1:(1 - 2).

[0072] And / or, the zirconium-containing additive includes zirconia; the addition of zirconia can improve the stability of the cathode material, thereby enhancing the cycle life of the cathode material. Meanwhile, the addition of zirconia can improve the electrical conductivity of the cathode material, and further enhance the charge and discharge efficiency of the cathode material.

[0073] And / or, the mass of the zirconium-containing additive is 0.1wt%-0.3wt% of the mass of the cathode material precursor; if the content of the zirconium-containing additive is too low, the effect of stabilizing the structure and enhancing the cycle life cannot be achieved; if the content of the zirconium-containing additive is too high, the lithium ion transport effect will be affected.

[0074] For example, the mass of the zirconium-containing additive can be 0.1wt%, 0.2wt%, 0.3wt% or any value between 0.1wt%-0.3wt% of the mass of the cathode material precursor.

[0075] In some embodiments, the mixing of the cathode material precursor, the lithium source, and the zirconium-containing additive is carried out in a high-speed mixer. The high-speed mixer can mix at a low speed and then at a high speed to achieve uniform mixing of the cathode material precursor, the lithium source, and the zirconium-containing additive. For example, the low speed of the high-speed mixer can be 100-300r / min, preferably 270r / min; the mixing time of the high-speed mixer at low speed can be 1-10min, preferably 5min; the high speed of the high-speed mixer can be 400-800r / min, preferably 500r / min; the mixing time of the high-speed mixer at high speed can be 10-30min, preferably 20min.

[0076] And / or, the sintering atmosphere for the first sintering includes oxygen;

[0077] And / or, the heating rate for the first sintering is 1-5℃ / min;

[0078] For example, the heating rate for the first sintering can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min or any value between 1-5℃ / min.

[0079] And / or, the temperature for the first sintering is 700-1000℃;

[0080] For example, the temperature for the first sintering can be 700℃, 800℃, 900℃, 1000℃ or any value between 700-1000℃.

[0081] And / or, the time for the first sintering is 12-14 hours.

[0082] For example, the time for the first sintering can be 12 hours, 13 hours, 14 hours or any value between 12-14 hours.

[0083] According to an embodiment of the present application, after the primary sintering is completed, the method further includes: pulverizing the material after the primary sintering to obtain a product after the primary sintering; specifically, a mechanical pulverizer can be used for pulverizing so that the D50 of the product after the primary sintering is between 8.5 - 11.5 μm;

[0084] According to an embodiment of the present application, the titanium-containing additive includes at least one of tetra-tert-butyl titanate, alkoxy titanate, and tetrabutyl titanate; by adding the titanium-containing additive, the crystal structure stability of the cathode material can be improved, and further the cycling and rate performance of the material can be improved.

[0085] And / or, the mass of the titanium-containing additive accounts for 0.1 wt% - 1 wt% of the mass of the product after the primary sintering;

[0086] For example, the mass of the titanium-containing additive can account for 0.1 wt%, 0.5 wt%, 1 wt% or any value between 0.1 wt% - 1 wt% of the mass of the product after the primary sintering.

[0087] According to an embodiment of the present application, the mixing of the product after the primary sintering and the titanium-containing additive is carried out in a high-speed mixer. When mixing the product after the primary sintering and the titanium-containing additive, the method further includes adding ethanol. Specifically, the titanium-containing additive can be mixed with ethanol to prepare a titanium-containing additive solution, and then the titanium-containing additive solution is sprayed onto the product after the primary sintering placed in the high-speed mixer. The spraying pressure of the titanium-containing additive solution can be 0.05 - 0.2 MPa.

[0088] And / or, the sintering atmosphere of the secondary sintering includes oxygen;

[0089] And / or, the heating rate of the secondary sintering is 1 - 5 °C / min;

[0090] For example, the heating rate of the secondary sintering can be 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min or any value between 1 - 5 °C / min.

[0091] And / or, the temperature of the secondary sintering is 400 - 800 °C;

[0092] For example, the temperature of the secondary sintering can be 400 °C, 500 °C, 600 °C, 700 °C, 800 °C or any value between 400 - 800 °C.

[0093] And / or, the time of the secondary sintering is 9 - 12 hours.

[0094] For example, the time of the secondary sintering can be 9 hours, 10 hours, 11 hours, 12 hours or any value between 9 - 12 hours.

[0095] According to an embodiment of the present application, the mass of aluminum nitrate accounts for 1.2 wt% - 2.4 wt% of the mass of the product after secondary sintering. The addition of aluminum nitrate can uniformly form a needle-like Al(NO3)3 coating layer on the material surface, which can reduce the surface impedance, improve the cycle stability and enhance the capacity retention rate. If the mass of aluminum nitrate is too low, the effect of significantly improving the performance cannot be achieved; if the mass of aluminum nitrate is too high, adverse effects such as low capacity will be caused.

[0096] For example, the mass of aluminum nitrate can account for 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt% or any value between 1.2 wt% - 2.4 wt% of the mass of the product after secondary sintering.

[0097] According to an embodiment of the present application, the mixing of the product after secondary sintering with water and aluminum nitrate includes: first mixing the product after secondary sintering with water, and then adding an aluminum nitrate solution, wherein the aluminum nitrate solution is prepared by mixing aluminum nitrate with water;

[0098] In some embodiments, the mixing of the product after secondary sintering with water and aluminum nitrate is carried out under stirring conditions, the stirring speed can be 200 - 800 r / min, and the addition speed of the aluminum nitrate solution can be 30 - 80 ml / min.

[0099] The mass ratio of the product after secondary sintering to water is 1: (1 - 1.8). For example, the mass ratio of the product after secondary sintering to water can be 1∶1, 1∶1.1, 1∶1.2, 1∶1.3, 1∶1.4, 1∶1.5, 1∶1.6, 1∶1.7, 1∶1.8 or any value between 1: (1 - 1.8). By adding water, the residual alkali on the material surface can be removed, and the processing performance of the material can be improved.

[0100] The mass ratio of the product after secondary sintering to the aluminum nitrate solution is 1: (2.012 - 2.024); for example, the mass ratio of the product after secondary sintering to the aluminum nitrate solution can be 1: 2.012, 1: 2.015, 1: 2.020, 1: 2.024 or any value between 1: (2.012 - 2.024).

[0101] The mass fraction of aluminum nitrate in the aluminum nitrate solution is 0.60% - 1.19%. For example, the mass fraction of aluminum nitrate in the aluminum nitrate solution can be 0.60%, 0.70%, 0.80%, 0.90%, 1.00%, 1.10%, 1.19% or any value between 0.60% - 1.19%.

[0102] According to an embodiment of the present application, the drying is carried out under vacuum conditions, and the temperature of the drying is 100 - 160 °C; for example, the drying temperature can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C or any value between 100 - 160 °C.

[0103] And / or, the drying time is 2 - 4 h. For example, the drying time can be 2 h, 3 h, 4 h or any value between 2 - 4 h.

[0104] According to an embodiment of the present application, the additive containing doping elements includes boric acid;

[0105] Furthermore, the additive containing doping elements further includes doping element simple substances, oxides of doping elements, etc.

[0106] And / or, the mass of the additive containing doping elements accounts for 0.05 wt% - 0.2 wt% of the mass of the material after coating; when the mass of the additive containing doping elements is within the above range, the diffusion rate of lithium ions can be increased while making the surface of the material smoother and reducing the generation of microcracks, so that the cathode material has more excellent rate performance. If the addition amount of the additive containing doping elements is too small, the purpose of significantly improving the material performance cannot be achieved; if the addition amount of the additive containing doping elements is too large, it will lead to an increase in the risk of low capacity of the material, an increase in the residual alkali on part of the surface, affecting the electrochemical performance and processing performance.

[0107] For example, the mass of the additive containing doping elements accounts for 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt% or any value between 0.05 wt% - 0.2 wt% of the mass of the material after coating.

[0108] In some embodiments, the mixing of the material after coating and the additive containing doping elements is carried out in a high-speed mixer.

[0109] And / or, the sintering atmosphere for the three - time sintering includes oxygen;

[0110] And / or, the heating rate for the three - time sintering is 1 - 5 °C / min;

[0111] For example, the heating rate for the three - time sintering can be 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min or any value between 1 - 5 °C / min.

[0112] And / or, the temperature for the three - time sintering is 200 - 400 °C; for example, the temperature for the three - time sintering can be 200 °C, 300 °C, 400 °C or any value between 200 - 400 °C.

[0113] And / or, the time of the three - stage sintering is 9 - 12 hours. For example, the time of the three - stage sintering can be 9 hours, 10 hours, 11 hours, 12 hours or any value between 9 - 12 hours.

[0114] This application also provides a ternary high - nickel cathode material, which is prepared by the preparation method of the ternary high - nickel cathode material described above.

[0115] This application also provides a lithium - ion battery, which includes the ternary high - nickel cathode material prepared by the preparation method of the ternary high - nickel cathode material described above or includes the ternary high - nickel cathode material described above.

[0116] This application also provides an electrical device, which includes the lithium - ion battery described above.

[0117] Hereinafter, specific embodiments will be used to describe the implementation scheme of this application in detail. However, those skilled in the art will understand that the following embodiments are only used to illustrate this application and should not be regarded as limiting the scope of this application. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0118] Example 1

[0119] Example 1 provides a ternary high - nickel cathode material, and its preparation method includes:

[0120] (1) Put the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor and lithium hydroxide into a high - speed mixer according to the molar ratio of lithium to the total content of metal nickel, cobalt and manganese being 1:1.05. At the same time, add nano - zirconia into the high - speed mixer, where the mass of nano - zirconia is 0.3wt% of the mass of the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor. The high - speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0121] (2) Load the mixed material in step (1) into a crucible, and the filling amount is 50% - 80% of the crucible capacity. Then put this material into a box - type furnace, where the sintering atmosphere is oxygen. Raise the temperature to 750℃ at a heating rate of 2℃ / min, and carry out the first - stage sintering at 750℃ for 13 hours to obtain the material after the first - stage sintering.

[0122] (3) Pulverize the material obtained in step (2) using a mechanical pulverizer, with D50 controlled between 8.5 - 9.5 μm.

[0123] (4) Take out the material obtained in step (3) and put it into a high - speed mixer. At the same time, dissolve 0.01 L of tetrabutyl titanate with a concentration of 99% in 1 L of ethanol with a concentration of 80% to obtain a tetrabutyl titanate solution. The mass of tetrabutyl titanate accounts for 0.1 wt% of the mass of the material after the first sintering. Spray the tetrabutyl titanate solution into the high - speed mixer during mixing, and the nozzle pressure is 0.05 MPa.

[0124] (5) Load the mixed material obtained in step (4) into a sagger, with the filling amount being 30% - 70% of the sagger capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Raise the temperature to 600 °C at a heating rate of 1 °C / min and conduct secondary sintering at 600 °C for 11 hours to obtain the material after secondary sintering.

[0125] (6) At 25 °C, weigh 12 g of aluminum nitrate and dissolve it in 1000 g of pure water to obtain an aluminum nitrate solution. Take 500 g of the material after secondary sintering in step (5), and place it in a water - washing kettle for water - washing according to the mass ratio of the material after secondary sintering to pure water of 1∶1.5. At the same time, gradually add the prepared aluminum nitrate solution drop by drop within 15 min for wet - process water - washing coating. After wet - process water - washing coating, conduct centrifugation, and then place it in an oven for vacuum drying. The temperature of the oven is 120 °C, and the drying time is 2 h to dry the material.

[0126] (7) Add the material obtained in step (6) and boric acid into a high - speed mixer. Among them, the mass of boric acid accounts for 0.1 wt% of the mass of the material obtained in step (6), and mix according to the mixing parameters in step (1).

[0127] (8) Load the material obtained in step (7) into a sagger, with the filling amount between 30% - 60% of the sagger volume. Put the material into a box furnace, raise the temperature to 300 °C at a heating rate of 1 °C / min, and conduct tertiary sintering at 300 °C for 11 hours to obtain the wet - coated ternary high - nickel cathode material.

[0128] Example 2

[0129] Example 2 provides a ternary high - nickel cathode material, and its preparation method includes:

[0130] (1) Ni 0.9 Co 0.06 Mn 0.04(OH)2 precursor and lithium hydroxide are put into a high-speed mixer according to a molar ratio of lithium to the total content of metal nickel, cobalt and manganese of 1:1.05. At the same time, nano-zirconia is added to the high-speed mixer, where the mass of nano-zirconia is 0.3 wt% of the mass of Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor. The high-speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0131] (2) The mixed material from step (1) is loaded into a crucible with a filling amount of 50%-80% of the crucible capacity. This material is put into a box furnace, where the sintering atmosphere is oxygen. The temperature is raised to 735 °C at a heating rate of 2 °C / min and sintered once at 735 °C for 13 hours to obtain the material after the first sintering.

[0132] (3) The material obtained in step (2) is crushed using a mechanical crusher, with D50 controlled between 8.5 - 9.5 μm. The SEM image of the crushed material is as shown in Figure 1 shown. It can be seen from Figure 1 that the average value of the primary particles in the material after the first sintering is between 0.4 and 0.8 μm.

[0133] (4) The material obtained in step (3) is taken out and put into a high-speed mixer. At the same time, 0.03 L of tetrabutyl titanate with a concentration of 99% is dissolved in 1 L of ethanol with a concentration of 80% to obtain a tetrabutyl titanate solution. The mass of tetrabutyl titanate accounts for 0.3 wt% of the mass of the material after the first sintering, and the tetrabutyl titanate solution is sprayed into the high-speed mixer during mixing, with the nozzle pressure being 0.1 MPa.

[0134] (5) The mixed material from step (4) is loaded into a crucible with a filling amount of 30%-70% of the crucible capacity. This material is put into a box furnace, where the sintering atmosphere is oxygen. The temperature is raised to 600 °C at a heating rate of 1 °C / min and sintered twice at 600 °C for 11 hours to obtain the material after the second sintering.

[0135] (6) At 25 °C, 8 g of aluminum nitrate is dissolved in 1000 g of pure water to obtain an aluminum nitrate solution. Take 500 g of the material after the second sintering in step (5) and place it in a water washing kettle for water washing according to a mass ratio of the material after the second sintering to pure water of 1:1. At the same time, 1000 g of the prepared aluminum nitrate solution is added dropwise within 15 min for wet water washing and coating. After wet water washing and coating, centrifugation is carried out, and then it is placed in an oven for vacuum drying. The temperature of the oven is 120 °C, and the drying time is 2 h to dry the material. The SEM image of the dried material is as shown inFigure 2 , Figure 3 and Figure 4 As shown in Figure 2 , Figure 3 and Figure 4 , acicular coating layers can be clearly seen and the coating materials are evenly distributed.

[0136] (7) Add the material obtained in step (6) and boric acid into a high-speed mixer. Among them, the mass of boric acid accounts for 0.1 wt% of the mass of the material obtained in step (6), and mix according to the mixing parameters in step (1).

[0137] (8) Load the material obtained in step (7) into a sagger, with the filling amount between 30% and 60% of the sagger volume. Put the material into a box furnace, heat it up to 300 °C at a heating rate of 1 °C / min, and perform three sinterings at a temperature of 300 °C for 11 hours to obtain a wet-coated ternary high-nickel cathode material. Its SEM image is as shown in Figure 5 .

[0138] Comparative Example 1

[0139] (1) Put the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor and lithium hydroxide into a high-speed mixer according to a molar ratio of lithium to the total content of nickel, cobalt and manganese of 1:1.05. At the same time, add nano-zirconia into the high-speed mixer. Among them, the mass of nano-zirconia is 0.3 wt% of the mass of the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor. The high-speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0140] (2) Load the material mixed in step (1) into a sagger, with the filling amount of 50%-80% of the sagger capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Heat the temperature to 750 °C at a heating rate of 2 °C / min, and perform one sintering at a temperature of 750 °C for 13 hours to obtain the material after one sintering.

[0141] (3) Crush the material obtained in step (2) using a mechanical crusher, and control D50 between 8.5 - 9.5 μm.

[0142] (4) Take out the material obtained in step (3) and put it into a high-speed mixer, and at the same time put in alumina and titanium dioxide. The mass of alumina accounts for 0.1 wt% of the mass of the material obtained in step (3), and the mass of titanium dioxide accounts for 0.12 wt% of the mass of the material obtained in step (3). Mix according to the mixing process in step (1) to obtain the dry-coated material.

[0143] (5) Put the material completed in step (4) into a crucible, and the filling amount is 30%-70% of the crucible capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Raise the temperature to 600 °C at a heating rate of 1 °C / min, and perform secondary sintering at a temperature of 600 °C for 11 hours to obtain the material after secondary sintering.

[0144] (6) Wash the material in step (5) for 15 min according to the mass ratio of material: pure water of 1:1.5, and perform centrifugation, and then perform vacuum drying in an oven. The temperature of the oven is 120 °C, and the drying time is 2 h to dry the material.

[0145] (7) Put the material obtained in step (6) and boric acid into a high-speed mixer. Among them, the mass of boric acid accounts for 0.1 wt% of the mass of the material obtained in step (6), and mix according to the mixing parameters in step (1).

[0146] (8) Put the material obtained in step (7) into a crucible, and the filling amount is between 30-60% of the crucible volume. Put the material into a box furnace, and raise the temperature to 300 °C at a heating rate of 1 °C / min, and perform tertiary sintering at a temperature of 300 °C for 11 hours to obtain the dry-coated ternary high-nickel cathode material.

[0147] Comparative Example 2

[0148] (1) Put Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor and lithium hydroxide into a high-speed mixer according to the molar ratio of lithium to the total content of metal nickel, cobalt and manganese of 1:1.05. The high-speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0149] (2) Put the material completed in step (1) into a crucible, and the filling amount is 50%-80% of the crucible capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Raise the temperature to 750 °C at a heating rate of 2 °C / min, and perform primary sintering at a temperature of 750 °C for 13 hours.

[0150] (3) Mechanically crush the material obtained after the first sintering in step (2) to control the D50 of the material between 8.5 - 11.5 μm, obtaining a high-nickel ternary cathode material without coating modification.

[0151] Comparative Example 3

[0152] (1) Put the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor and lithium hydroxide into a high-speed mixer according to the molar ratio of lithium to the total content of metal nickel, cobalt, and manganese being 1:1.05. At the same time, add nano-zirconia to the high-speed mixer, where the mass of nano-zirconia is 0.3 wt% of the mass of the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor. The high-speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0153] (2) Load the material completed in step (1) into a crucible, with the filling amount being 50% - 80% of the crucible capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Raise the temperature to 750°C at a heating rate of 2°C / min and conduct the first sintering at 750°C for 13 hours to obtain the material after the first sintering.

[0154] (3) Crush the material obtained in step (2) using a mechanical crusher, with D50 controlled between 8.5 - 9.5 μm.

[0155] (4) Take out the material obtained in step (3) and put it into a high-speed mixer. At the same time, dissolve 0.01 L of tetrabutyl titanate with a concentration of 99% in 1 L of ethanol with a concentration of 80% to obtain a tetrabutyl titanate solution. The mass of tetrabutyl titanate accounts for 0.1 wt% of the mass of the material after the first sintering, and spray the tetrabutyl titanate solution into the high-speed mixer during mixing, with the nozzle pressure being 0.05 MPa.

[0156] (5) Load the material completed in step (4) into a crucible, with the filling amount being 30% - 70% of the crucible capacity. Put this material into a box furnace, where the sintering atmosphere is oxygen. Raise the temperature to 600°C at a heating rate of 1°C / min and conduct the second sintering at 600°C for 11 hours to obtain the material after the second sintering.

[0157] (6) Take 500 g of the material after secondary sintering in step (5), place it in a water-washing kettle according to the mass ratio of the material after secondary sintering to pure water of 1:1.5 for water washing. After water washing, centrifuge it, and then place it in an oven for vacuum drying. The temperature of the oven is 120 °C, and the drying time is 2 h to dry the material.

[0158] (7) Add the material obtained in step (6) and boric acid to a high-speed mixer. Among them, the mass of boric acid accounts for 0.1 wt% of the mass of the material obtained in step (6), and mix according to the mixing parameters in step (1).

[0159] (8) Load the material obtained in step (7) into a sagger, and the filling amount is between 30% and 60% of the sagger volume. Put the material into a box furnace, and heat it up to 300 °C at a heating rate of 1 °C / min, and carry out three times of sintering at a temperature of 300 °C for 11 hours to obtain a ternary high-nickel cathode material.

[0160] Comparative Example 4

[0161] (1) Put the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor and lithium hydroxide into a high-speed mixer according to the molar ratio of lithium to the total content of metal nickel, cobalt and manganese of 1:1.05. At the same time, add nano-zirconia to the high-speed mixer. Among them, the mass of nano-zirconia is 0.3 wt% of the mass of the Ni 0.9 Co 0.06 Mn 0.04 (OH)2 precursor. The high-speed mixer rotates at a low speed of 270 r / min for 5 min and at a high speed of 500 r / min for 20 min to mix evenly.

[0162] (2) Load the material mixed in step (1) into a sagger, and the filling amount is 50%-80% of the sagger capacity. Put this material into a box furnace, and the sintering atmosphere is oxygen. Heat up the temperature to 750 °C at a heating rate of 2 °C / min, and carry out one-time sintering at a temperature of 750 °C for 13 hours to obtain the material after one-time sintering.

[0163] (3) Crush the material obtained in step (2) using a mechanical crusher, and control D50 between 8.5 - 9.5 μm.

[0164] (4) Take out the material obtained in step (3) and put it into a high-speed mixer. At the same time, dissolve 0.01 L of tetrabutyl titanate with a concentration of 99% in 1 L of ethanol with a concentration of 80% to obtain a tetrabutyl titanate solution. The mass of tetrabutyl titanate accounts for 0.1 wt% of the mass of the material after one-time sintering, and spray the tetrabutyl titanate solution into the high-speed mixer during mixing, and the nozzle pressure is 0.05 MPa.

[0165] (5) Load the material completed in step (4) into a sagger, with the filling amount being 30% - 70% of the sagger capacity. Feed this material into a box furnace, where the sintering atmosphere is oxygen. Increase the temperature to 600°C at a heating rate of 1°C / min, and perform secondary sintering at 600°C for 11 hours to obtain the material after secondary sintering.

[0166] (6) Add the material obtained in step (5) and boric acid into a high-speed mixer. Among them, the mass of boric acid accounts for 0.1 wt% of the mass of the material obtained in step (5), and mix according to the mixing parameters in step (1).

[0167] (7) Load the material obtained in step (6) into a sagger, with the filling amount being between 30% and 60% of the sagger volume. Put the material into a box furnace, heat it to 300°C at a heating rate of 1°C / min, and perform tertiary sintering at 300°C for 11 hours to obtain a ternary high-nickel cathode material.

[0168] Assemble the cathode materials prepared in Examples 1 - 2 and Comparative Examples 1 - 4 into lithium anode button half-cells, and test the electrochemical performance of the batteries. The test conditions are: 0.1C, 3.0 - 4.3V. And test the residual alkali content. The test method for the residual alkali content is titration, and a standard solution of 0.03 mol / L is used for titration.

[0169] The comparison of the test results between Examples 1 - 2 and Comparative Examples 1 - 4 is shown in Table 1.

[0170] Table 1 Comparison table of test results between Examples 1 - 2 and Comparative Examples 1 - 4

[0171]

[0172] As can be seen from Table 1, Examples 1 - 2 can simultaneously have a relatively high charge-discharge capacity and a relatively low residual alkali content, and their comprehensive performance is significantly better than that of Comparative Examples 1 - 4.

[0173] Compared with Examples 1 - 2, Comparative Example 1 has a lower charge capacity, discharge capacity, discharge efficiency, and a higher residual alkali content. This may be because aluminum and titanium in Comparative Example 1 are introduced in a dry method, resulting in poor uniformity and consistency of coating, and thus poor electrochemical performance of the cathode material.

[0174] Compared with Examples 1-2, Comparative Example 2 has a lower charge capacity, discharge capacity, discharge efficiency, and a higher residual alkali content. This may be due to the combined effects of multiple factors in Comparative Example 2, such as not introducing zirconium-containing additives, titanium-containing additives, not coating aluminum nitrate on the material surface, not performing water washing, and not introducing doping element-containing additives. These treatment steps and the use of additives are crucial for improving the comprehensive performance of the cathode material, and their absence directly deteriorates the electrochemical performance of the cathode material in Comparative Example 2.

[0175] Compared with Examples 1-2, Comparative Example 3 has a lower charge capacity and discharge capacity, which may be due to the fact that Comparative Example 3 did not add an aluminum nitrate solution and no aluminum nitrate coating layer was formed on the surface of the cathode material.

[0176] Compared with Examples 1-2, Comparative Example 4 has a lower charge capacity and discharge capacity, and at the same time, Comparative Example 3 has a higher residual alkali content. This may be due to the fact that Comparative Example 4 omitted the water washing step and the step of adding an aluminum nitrate solution.

[0177] From the analysis of the above examples and comparative examples, it can be seen that the ternary cathode material after wet coating modification has better discharge capacity performance, lower residual alkali, and a more uniform coating layer.

[0178] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0179] In addition, those skilled in the art can understand that although some of the embodiments herein include certain features included in other embodiments but not other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present application, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art.

Claims

1. A method for preparing a ternary high-nickel positive electrode material, characterized in that: include: The positive electrode material precursor, the lithium source and the zirconium-containing additive are mixed and sintered once to obtain a sintered product; Mixing a titanium-containing additive with 80% ethanol to prepare a titanium-containing additive solution, and then spraying the titanium-containing additive solution on a primary sintered product placed in a high-speed mixer, and performing secondary sintering to obtain a secondary sintered product, wherein the titanium-containing additive comprises at least one of tetra-tert-butyl titanate, alkoxy titanate, and tetrabutyl titanate, the mass of the titanium-containing additive accounts for 0.1wt%-1wt% of the mass of the primary sintered product, the temperature of the secondary sintering is 400-800°C, and the time of the secondary sintering is 9-12 hours; First, the secondary sintered product is mixed with water, and then an aluminum nitrate solution is added, wet-washed and coated, filtered, and dried to obtain a coated material, wherein the mass ratio of the secondary sintered product to water is 1: (1-1.8), the mass ratio of the secondary sintered product to the aluminum nitrate solution is 1: (2.012-2.024), the mass fraction of aluminum nitrate in the aluminum nitrate solution is 0.60%-1.19%, and the coated material includes a needle-shaped Al(NO3)3 coating layer; The coated material is mixed with an additive containing a doping element, and sintered three times to obtain a ternary high-nickel positive electrode material, wherein the doping element is B; The positive electrode material precursor includes Ni x Co y Mn z (OH)2, where x≥0.9, y>0, z>0, x+y+z=1.

2. The method for preparing a ternary high-nickel cathode material according to claim 1, characterized in that: The lithium source includes lithium hydroxide; And / or, the molar ratio of lithium in the lithium source to the total content of nickel, cobalt and manganese in the positive electrode material precursor is 1:(1-2); and / or, the zirconium-containing additive comprises zirconium oxide; and / or, the mass of the zirconium-containing additive is 0.1wt%-0.3wt% of the mass of the positive electrode material precursor; and / or, the sintering atmosphere of the primary sintering includes oxygen; And / or, the heating rate of the primary sintering is 1-5°C / min; And / or, the primary sintering temperature is 700-1000°C; And / or, the time of the primary sintering is 12-14 hours.

3. The method for preparing a ternary high-nickel cathode material according to claim 1, characterized in that: The sintering atmosphere of the secondary sintering includes oxygen; And / or, the heating rate of the secondary sintering is 1-5°C / min.

4. The method for preparing a ternary high-nickel cathode material according to claim 1, characterized in that: The drying is carried out under vacuum conditions at a temperature of 100-160°C; And / or, the drying time is 2-4 hours.

5. The method for preparing a ternary high-nickel cathode material according to any one of claims 1 to 4, characterized in that: Additives containing doping elements include boric acid; and / or, the mass of the additive containing the doping element accounts for 0.05wt%-0.2wt% of the mass of the coated material; and / or, the sintering atmosphere of the third sintering includes oxygen; And / or, the heating rate of the three sinterings is 1-5°C / min; And / or, the temperature of the three sinterings is 200-400°C; And / or, the time of the three sinterings is 9-12 hours.

6. A ternary high nickel positive electrode material, characterized in that: The ternary high-nickel positive electrode material is prepared by the preparation method of the ternary high-nickel positive electrode material according to any one of claims 1 to 5.

7. A lithium ion battery, characterized in that: The lithium-ion battery comprises the ternary high-nickel positive electrode material prepared by the method for preparing the ternary high-nickel positive electrode material according to any one of claims 1 to 5, or comprises the ternary high-nickel positive electrode material according to claim 6.

8. An electrical device, characterized in that: The electrical equipment comprises the lithium-ion battery according to claim 7.

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