Nickel-based positive electrode material as well as preparation method and application thereof

Abstract

The invention belongs to the field of battery materials, and discloses a nickel positive electrode material and a preparation method and application thereof.The preparation method comprises the steps that a polycrystalline precursor of NixM1-x (OH) 2, a lithium source, glutenin and gliadin are ground and mixed, and mixed powder is obtained; mixing the solvent and the mixed powder to obtain slurry, and drying to obtain a mixture; and pre-sintering the mixture in an oxygen atmosphere, and then heating and roasting for a certain time to obtain solid particles, namely the nickel-based positive electrode material. By adding glutenin and gliadin and combining with a roasting process, primary crystal grains of a polycrystalline precursor of NixM1-x (OH) 2 continuously grow in the roasting process, so that the prepared nickel-based positive electrode material is of a submicron single-crystal structure, the specific surface area of the positive electrode material is reduced, the possibility of side reaction is reduced, and the service life of the positive electrode material is prolonged. The structural stability of the positive electrode material can be further improved, the cycle performance of the battery is finally improved, and the volume energy density of the battery is increased.

Description

Technical Field

[0001] This invention belongs to the field of battery materials and relates to a cathode material, specifically a nickel-based cathode material and its preparation method and application. Background Art

[0002] Lithium-ion battery cathode materials are mainly lithium cobalt oxide (LiCoO2). Although they have high operating voltage and energy density, cobalt resources are scarce and expensive, and there are safety issues at high voltages. With technological advancements, researchers have discovered that nickel-based cathode materials have advantages such as high specific capacity and high energy density. Furthermore, nickel resources are relatively abundant and their prices are more stable. This gives nickel-based cathode materials a cost advantage in large-scale applications, which helps reduce battery production costs.

[0003] To further improve the energy density and stability of nickel-based cathode materials, existing technologies typically prepare single-crystal particles at higher sintering temperatures. Single-crystal particles have advantages over polycrystalline particles in terms of cycle performance and thermal stability.

[0004] However, single-crystal particles still have the following problems: First, although large-sized single-crystal particles are beneficial to improving energy density, they weaken the rapid transport of lithium ions, resulting in poor rate performance and easy capacity decay; Second, although small-sized single-crystal particles provide a shorter lithium ion diffusion path, their high degree of nano-sizing and large specific surface area reduce energy density and first coulombic efficiency; Third, single-crystal particles require higher sintering temperatures, resulting in higher preparation costs.

[0005] It is evident that existing technologies have failed to effectively resolve the triangular contradiction between energy density, cycle performance, and cost. Summary of the Invention

[0006] In view of the defects and deficiencies of the existing technology, the present invention provides, firstly, a method for preparing a nickel-based cathode material; secondly, a nickel-based cathode material; and thirdly, a battery.

[0007] In a first aspect, the present invention provides a method for preparing a nickel-based cathode material, comprising the following steps: Step 1, Grinding and mixing Ni x M 1-x A mixed powder was obtained by combining a polycrystalline precursor of (OH)2, a lithium source, glutenin, and gliadin. Step 2: Mix the solvent and the powder to obtain a slurry; then dry the slurry to obtain a mixture. Step 3: Pre-calcine the mixture in an oxygen atmosphere, then heat and calcine for a certain time to obtain solid particles, which are the nickel-based cathode material. Among them, Ni x M1-x In the polycrystalline precursor of (OH)2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30≤x≤1.

[0008] Preferably, in step 1, the lithium source is any one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxide, lithium acetate, lithium oxalate, and lithium citrate.

[0009] Preferably, in step 1, the mixed powder contains lithium and Ni from the lithium source. x M 1-x The molar ratio of the polycrystalline precursor of (OH)₂ is 1~1.08:1; the mass ratio of glutenin to gliadin is 0.65~1:1; NixM 1-x The ratio of the mass of the polycrystalline precursor of (OH)2 to the sum of the masses of glutenin and gliadin is 1:0.01~0.3.

[0010] Preferably, in step 1, the molecular weight of glutenin is 100~5000kDa; the molecular weight of gliadin is 30~80kDa.

[0011] Preferably, in step 1, the grinding speed is 50~300 r / min and the grinding time is 0.5~4 h.

[0012] Preferably, in step 2, the solvent is at least one of deionized water, ethanol, acetone, ethylene glycol, propylene glycol, N-methylpyrrolidone, dimethylformamide, cyclohexanone, and γ-butyrolactone.

[0013] Preferably, in step 2, the liquid-to-solid ratio of the solvent and the mixed powder is 0.05~0.3 mL / g.

[0014] Preferably, in step 2, the drying temperature is 60~80℃ and the drying time is 1~8h.

[0015] Preferably, in step 3, the oxygen content in the oxygen-containing atmosphere is 21% to 100%.

[0016] Preferably, in step 3, the pre-firing temperature is 300~500℃ and the pre-firing time is 1~6h.

[0017] Preferably, in step 3, the roasting temperature is 650~1000℃ and the roasting time is 10~25h.

[0018] Preferably, in step 3, the heating rate during pre-firing and roasting is 1~10℃ / min.

[0019] Secondly, the present invention provides a nickel-based cathode material, which is prepared by the above-described preparation method.

[0020] Preferably, the general chemical formula of the nickel-based cathode material is: LiNi x M 1-x O2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30 ≤ x ≤ 1.

[0021] Preferably, the nickel-based cathode material has a submicron single-crystal structure, with primary particles ranging from 500 nm to 1 μm.

[0022] Thirdly, the present invention provides a battery comprising a nickel-based cathode material prepared by the above-described preparation method.

[0023] Compared with the prior art, one or more technical solutions provided by the present invention have at least one of the following beneficial effects: (1) By adding glutenin and gliadin and combining them with the roasting process, Ni x M 1-x The primary grains of the polycrystalline precursor (OH)2 continuously grow, resulting in a submicron single-crystal structure for the nickel-based cathode material. This reduces the specific surface area of ​​the cathode material, decreases the possibility of side reactions, and further enhances the structural stability of the cathode material, ultimately improving battery cycle performance and increasing battery volumetric energy density.

[0024] (2) The raw materials used in the preparation method provided by the present invention are common and inexpensive; the preparation process is simple and can be directly applied to existing industrial production lines for production without the need for additional equipment or adjustment of existing industrial production lines. It is suitable for large-scale industrial production and is conducive to marketization and commercialization. Attached Figure Description

[0025] Figure 1 A process flow diagram of the preparation method of the nickel-based cathode material provided by the present invention; Figure 2 The graphs show the rate performance test results of batteries assembled from the cathode materials prepared in Examples 1-4 and Comparative Examples 1-4 at 0.1-5C. Figure 3 The graph shows the cycle performance of batteries assembled from the cathode materials prepared in Example 1 and Comparative Examples 1-4 at 1C. Figure 4 The image shows the XRD pattern of the nickel-based cathode material prepared in Example 1. Figure 5 SEM images of the nickel-based cathode materials prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0026] The present invention provides the following specific technical solutions.

[0027] In a first aspect, the present invention provides a method for preparing a nickel-based cathode material, comprising the following steps: Step 1, Grinding and mixing Ni x M 1-x A mixed powder was obtained by combining a polycrystalline precursor of (OH)2, a lithium source, glutenin, and gliadin. Step 2: Mix the solvent and the powder to obtain a slurry; then dry the slurry to obtain a mixture. Step 3: Pre-calcine the mixture in an oxygen atmosphere, then heat and calcine for a certain time to obtain solid particles, which are the nickel-based cathode material. Among them, Ni x M 1-x In the polycrystalline precursor of (OH)2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30≤x≤1.

[0028] The inventors discovered through research that by adding glutenin and gliadin, Ni can be reduced during the roasting process. x M 1-x As the primary grains of the polycrystalline precursor (OH)2 grow continuously, the resulting nickel-based cathode material exhibits a submicron single-crystal structure. This reduces the specific surface area of ​​the cathode material, decreases the likelihood of side reactions, and further enhances the structural stability of the cathode material, ultimately improving battery cycle performance and increasing battery volumetric energy density.

[0029] Furthermore, the preparation method provided by this invention uses common and inexpensive raw materials; the preparation process is simple and can be directly applied to existing industrial production lines without the need for additional equipment or adjustments to existing industrial production lines; the calcination temperature during mixed lithium calcination is lower than that of existing technologies, reducing energy consumption and further lowering production costs, making it suitable for large-scale industrial production and beneficial for marketization and commercialization.

[0030] Preferably, in step 1, the lithium source is any one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxide, lithium acetate, lithium oxalate, and lithium citrate.

[0031] Preferably, in step 1, the mixed powder contains lithium and Ni from the lithium source. x M 1-x The molar ratio of the polycrystalline precursor of (OH)₂ is 1~1.08:1; the mass ratio of glutenin to gliadin is 0.65~1:1; Ni x M 1-x The ratio of the mass of the polycrystalline precursor of (OH)2 to the sum of the masses of glutenin and gliadin is 1:0.01~0.3.

[0032] Through research, the inventors discovered that a slightly excessive amount of lithium source can compensate for the lithium loss caused during the roasting process, making the lithiation process more complete and generating the target product with accurate stoichiometry.

[0033] Glutelin and gliadin help control the size of primary particles, resulting in materials with uniform particle size and good dispersibility, thereby improving the electrochemical performance of the materials.

[0034] Ni x M 1-x The mass ratio of the polycrystalline precursor of (OH)₂ to the sum of the masses of glutenin and gliadin is 1:0.01~0.3. This avoids introducing excessive impurities and creates a relatively stable reaction environment during calcination, which helps control the reaction rate and progress, and slows down the reaction of Ni. x M 1-x The decomposition and reaction rate of the polycrystalline precursor of (OH)2 make the reaction more uniform and complete, thereby improving the crystallinity and performance of the material.

[0035] Preferably, in step 1, the molecular weight of glutenin is 100~5000kDa; the molecular weight of gliadin is 30~80kDa.

[0036] Preferably, in step 1, the grinding speed is 50~300 r / min and the grinding time is 0.5~4 h.

[0037] Preferably, in step 2, the solvent is deionized water, ethanol, acetone, ethylene glycol, propylene glycol, N-methylpyrrolidone, dimethylformamide, cyclohexanone, or γ-butyrolactone.

[0038] Preferably, in step 2, the liquid-to-solid ratio of the solvent and the mixed powder is 0.05~0.3 mL / g.

[0039] Preferably, in step 2, the drying temperature is 60~80℃ and the drying time is 1~8h.

[0040] In practical applications, the drying temperature and time can be adjusted according to the actual situation. The inventors proposed a relatively mild drying temperature of 60-80℃, which can effectively remove the solvent in the slurry while avoiding compositional changes or performance losses that may be caused by excessively high temperatures. For the preparation of nickel-based cathode materials, excessively high temperatures may cause the precursor to react prematurely, the lithium source to volatilize, or lead to excessive decomposition of organic matter (glutenin and gliadin), affecting the composition and structure of the final cathode material.

[0041] Preferably, in step 3, the oxygen content in the oxygen-containing atmosphere is 21% to 100%.

[0042] Preferably, in step 3, the pre-firing temperature is 300~500℃ and the pre-firing time is 1~6h.

[0043] Preferably, in step 3, the roasting temperature is 650~1000℃ and the roasting time is 10~25h.

[0044] Through research, the inventors discovered that the calcination process and the combination of raw materials help to form nickel-based cathode materials with submicron-scale structures, reduce the formation of impurity phases, and thus improve the purity and performance of the materials.

[0045] Preferably, in step 3, the heating rate during pre-firing and roasting is 1~10℃ / min.

[0046] Secondly, this invention provides a nickel-based cathode material, prepared by the above-described method; the general chemical formula of the nickel-based cathode material is: LiNi x M 1-x O2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30 ≤ x ≤ 1.

[0047] Preferably, the nickel-based cathode material has a submicron single-crystal structure, with primary particles ranging from 500 nm to 1 μm.

[0048] Thirdly, the present invention provides a battery comprising a nickel-based cathode material prepared by the above-described preparation method.

[0049] To make the technical problems, technical solutions and technical advantages of the present invention clearer, a detailed description will be given below with reference to specific examples. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0050] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0051] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0052] Figure 1 This invention provides a process flow diagram for preparing a nickel-based cathode material.

[0053] Example 1: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 10g Ni 0.8 Co 0.1 Mn 0.1After mixing the polycrystalline precursor of (OH)2, 4.77g of lithium hydroxide (LiOH·H2O), 0.25g of glutenin and 0.25g of gliadin, a mixed powder was obtained. Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 70°C for 5 hours to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 480°C for 5 hours in an oxygen atmosphere, and then heated to 750°C for 12 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 5°C / min. The resulting solid particles are nickel-based cathode materials.

[0054] Comparative Example 1: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 10g Ni 0.8 Co 0.1 Mn 0.1 A mixed powder was obtained by mixing (OH)2 polycrystalline precursor and 4.77 g of lithium hydroxide (LiOH·H2O); Step 2: The mixture obtained in Step 1 is pre-calcined at 480°C for 5 hours in an oxygen atmosphere, and then heated to 750°C for 12 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 5°C / min. The resulting solid particles are nickel-based cathode materials.

[0055] Comparative Example 2: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 10g Ni 0.8 Co 0.1 Mn 0.1 After mixing the polycrystalline precursor of (OH)2, 4.77 g of lithium hydroxide (LiOH·H2O), and 0.5 g of wheat flour, a mixed powder was obtained. Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 70°C for 5 hours to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 480°C for 5 hours in an oxygen atmosphere, and then heated to 750°C for 12 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 5°C / min. The resulting solid particles are nickel-based cathode materials.

[0056] Comparative Example 3: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 10g N i0.8 Co 0.1 Mn 0.1A mixed powder was obtained by mixing a single crystal precursor of (OH)2, 4.77 g of lithium hydroxide (LiOH·H2O), 0.25 g of glutenin and 0.25 g of gliadin. Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 70°C for 5 hours to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 480°C for 5 hours in an oxygen atmosphere, and then heated to 750°C for 12 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 5°C / min. The resulting solid particles are nickel-based cathode materials.

[0057] Comparative Example 4: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 10g Ni 0.8 Co 0.1 Mn 0.1 After mixing the polycrystalline precursor of (OH)2, 4.77g of lithium hydroxide (LiOH·H2O), 0.25g of glutenin and 0.25g of gliadin, a mixed powder was obtained. Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 70°C for 5 hours to obtain a mixture. Step 3: Place the mixture obtained in Step 2 into an oxygen atmosphere and calcine at 750°C for 17 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during calcinement is 5°C / min. The resulting solid particles are nickel-based cathode materials.

[0058] Example 2: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 15g Ni 0.6 Co 0.2 Mn 0.2 After mixing (OH)2 polycrystalline precursor, 6.21g lithium carbonate, 0.5g glutenin and 1g gliadin, a mixed powder was obtained; Step 2: Mix N-methylpyrrolidone and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 60°C for 1 hour to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 400°C for 5 hours in an oxygen atmosphere, and then heated to 800°C for 15 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 3°C / min. The resulting solid particles are nickel-based cathode materials.

[0059] Example 3: A method for preparing a nickel-based cathode material includes the following steps: Step 1, mix 25g Ni 0.3 Co 0.3 Mn 0.3 After mixing the polycrystalline precursor of (OH)2, 20.5g of lithium nitrate, 0.54g of glutenin and 0.71g of gliadin, a mixed powder was obtained. Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 80°C for 2 hours to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 500°C for 6 hours in an oxygen atmosphere, and then heated to 1000°C for 16 hours. The oxygen content in the oxygen atmosphere is 21%, and the heating rate during pre-calcination and calcination is 10°C / min. The resulting solid particles are nickel-based cathode materials.

[0060] Example 4: A method for preparing a nickel-based cathode material includes the following steps: Step 1: Mix 12g of Ni(OH)2 polycrystalline precursor, 1.93g of lithium oxide, 0.9g of glutenin and 0.9g of gliadin to obtain a mixed powder; Step 2: Mix deionized water and the mixed powder obtained in Step 1 to obtain a slurry; then dry the slurry at 80°C for 8 hours to obtain a mixture. Step 3: The mixture obtained in Step 2 is pre-calcined at 500°C for 6 hours in an oxygen atmosphere, and then heated to 680°C for 15 hours. The oxygen content in the oxygen atmosphere is 100%, and the heating rate during pre-calcination and calcination is 10°C / min. The resulting solid particles are nickel-based cathode materials.

[0061] The nickel-based cathode materials prepared in Examples 1-4 and Comparative Examples 1-4 were respectively added to conductive carbon black and PVDF in a ratio of 8:1:1 with an appropriate amount of N-methylpyrrolidone (NMP) solution. The viscosity of the slurry was adjusted and the mixture was stirred evenly to a concentration of 3-5 mg / cm³. 2 The loading capacity was coated on the current collector aluminum foil and dried under vacuum at 85°C for 12 hours; 12mm circular electrode sheets were cut out and CR2032 coin cells were assembled in an argon atmosphere glove box; lithium metal was used as the negative electrode, Celgard2500 microporous polypropylene membrane was used as the separator, and 1M LiPF6 (ethylene carbonate (EC): diethyl carbonate (DEC): ethyl methyl carbonate (EMC) volume ratio of 1:1:1) was used as the electrolyte; the rate performance of the batteries assembled with the positive electrode materials prepared in Examples 1-4 and Comparative Examples 1-4 was tested at 25°C at different rates (1C=180mAh / g) using the Blue Battery Test System, and the cycle performance of the batteries assembled with the positive electrode materials prepared in Examples 1-4 and Comparative Examples 1-4 was tested at 25°C at 1C rate. The test data are shown in Table 1.

[0062] Table 1. Electrochemical performance (mAh / g) of batteries assembled in Examples 1-4 and Comparative Examples 1-4 Figure 2 The graphs show the rate performance test results of batteries assembled from the cathode materials prepared in Examples 1-4 and Comparative Samples 1-4 at 0.1-5C. Figure 3 The graph shows the cycle performance of batteries assembled from the cathode materials prepared in Example 1 and Comparative Samples 1-4 at 1C.

[0063] Comparing the rate performance and cycle performance of batteries assembled from the cathode materials prepared in Example 1 and Comparative Example 1, it can be seen that the submicron-sized single-crystal nickel-based cathode material prepared by the method provided by the present invention exhibits higher rate performance and better cycle performance. After 200 cycles, the capacity retention rate remains at 97.0%, which is significantly higher than the rate performance and cycle performance of the nickel-based cathode material prepared in Comparative Example 1. This indirectly proves that the preparation method provided by the present invention can promote the full growth of primary grains of nickel-based cathode materials during the calcination process to form a submicron-sized single-crystal structure, which is beneficial to enhancing the diffusion ability of lithium ions, improving the rate performance of the battery, and greatly reducing the electrochemical capacity decay caused by side reactions of nickel-based cathode materials in the electrolyte.

[0064] Comparing the rate performance and cycle performance of batteries assembled from the cathode materials prepared in Example 1 and Comparative Example 2, it can be seen that the cathode material prepared by the method provided by the present invention has superior rate performance and cycle performance.

[0065] Comparing the rate performance and cycle performance of half-cells assembled from the cathode materials prepared in Example 1 and Comparative Example 3, it can be seen that Comparative Example 3 uses N i0.8 Co 0.1 Mn 0.1 The rate performance and cycle performance of single-crystal nickel-based cathode materials prepared from single-crystal (OH)₂ precursors are poor, mainly because the particle size of single-crystal nickel-based cathode materials is too large, making the grains prone to breakage during cycling. This affects the rapid insertion / extraction and transport of lithium ions, resulting in poor rate performance and easy capacity decay. Therefore, the preparation method provided by this invention can synthesize nickel-based cathode materials with submicron-scale single-crystal structures, reducing the material surface area and improving the lithium ion diffusion rate. Compared with the prior art, the calcination temperature is also lower than the temperature required for preparing single-crystal nickel-based cathode materials, thus reducing processing costs.

[0066] Comparing the rate performance and cycle performance of the half-cells assembled from the cathode materials prepared in Example 1 and Comparative Example 4, it can be seen that the cathode material prepared by one sintering in Comparative Example 4 has poor rate performance and cycle performance. The inventors speculate that this may be because the calcination process affects the crystal structure of the nickel-based cathode material. The nickel-based cathode material prepared in Comparative Example 4 is prone to defects and uneven voids, which affect the electrochemical performance of the cathode material.

[0067] Comparing the rate performance and cycle performance of batteries assembled from the cathode materials prepared in Examples 1-4, their rate performance and cycle performance are similar, which proves that the preparation method provided by the present invention can use polycrystalline nickel-based precursor materials to prepare submicron-scale single-crystal nickel-based cathode materials, thereby improving the rate performance and cycle performance of batteries.

[0068] Figure 4 The image shows the XRD pattern of the nickel-based cathode material prepared in Example 1. Figure 4 It can be known that LiNi 0.8 Co 0.1 Mn 0.1 The O2 cathode material exhibits high phase purity, high crystallinity, and no impurity characteristic diffraction peaks, fully demonstrating that the nickel-based cathode material synthesized by the preparation method provided in this invention has a pure phase, good crystal structure, and high crystallinity. This is beneficial for reducing volume changes and structural stress during the high-temperature calcination stage, thereby improving the material's consistency and stability.

[0069] Figure 5 Figure 1 shows SEM images of the nickel-based cathode materials prepared in Example 1 and Comparative Example 1. Figure (a) is the SEM image of the nickel-based cathode material prepared in Comparative Example 1, and Figure (b) is the SEM image of the nickel-based cathode material prepared in Example 1. Figure 5 As shown, the primary grain size of Comparative Example 1 is approximately 200-400 nm, while the primary grain size of Example 1 is approximately 700-1000 nm. This demonstrates that the preparation process provided by the present invention can significantly increase the primary grain size, thereby improving the energy density of the cathode material and enhancing the stability of its electrochemical performance.

[0070] The above-described embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-based cathode material, characterized in that, Includes the following steps: Step 1, Grinding and mixing Ni x M 1-x A mixed powder was obtained by combining (OH)2 polycrystalline precursor, lithium source, glutenin and gliadin. Step 2: Mix the solvent and the powder to obtain a slurry; then dry the slurry to obtain a mixture. Step 3: Pre-calcine the mixture in an oxygen atmosphere, then heat and calcine for a certain time to obtain solid particles, which are the nickel-based cathode material. Among them, Ni x M 1-x In the polycrystalline precursor of (OH)2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30≤x≤1.

2. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 1, the lithium element and Ni in the lithium source are mixed in the powder. x M 1-x The molar ratio of the polycrystalline precursor of (OH)₂ is 1~1.08:1; the mass ratio of glutenin to gliadin is 0.65~1:1; Ni x M 1-x The ratio of the mass of the polycrystalline precursor of (OH)2 to the sum of the masses of glutenin and gliadin is 1:0.01~0.

3.

3. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 1, the lithium source is any one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxide, lithium acetate, lithium oxalate, and lithium citrate.

4. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 2, the solvent is at least one of deionized water, ethanol, acetone, ethylene glycol, propylene glycol, N-methylpyrrolidone, dimethylformamide, cyclohexanone, and γ-butyrolactone.

5. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 3, the pre-firing temperature is 300~500℃ and the pre-firing time is 1~6h.

6. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 3, the roasting temperature is 650~1000℃ and the roasting time is 10~25h.

7. The method for preparing the nickel-based cathode material as described in claim 1, characterized in that, In step 2, the liquid-to-solid ratio of the solvent and the mixed powder is 0.05~0.3mL / g.

8. A nickel-based cathode material, characterized in that, The nickel-based cathode material is prepared by the method according to any one of claims 1 to 7; the general chemical formula of the nickel-based cathode material is: LiNi x M 1-x O2, M is any one or more of Co, Mn, Al, Mg, Ti, Fe, V, B, W, La, Nb, and Ta, and 0.30 ≤ x ≤ 1.

9. The nickel-based cathode material as described in claim 8, characterized in that, The nickel-based cathode material has a submicron single-crystal structure, with primary particles ranging from 500 nm to 1 μm.

10. A battery, characterized in that, This includes nickel-based cathode materials prepared by the preparation method according to any one of claims 1 to 7, or nickel-based cathode materials according to any one of claims 8 to 9.

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