High-nickel positive electrode material, preparation method, positive electrode sheet, battery, and electric device

Abstract

This application provides a high-nickel cathode material, a preparation method, a cathode sheet, a battery, and an electrical device, belonging to the technical field of lithium-ion battery cathode materials. The high-nickel cathode material has a hollow structure, comprising a cathode material matrix and a coating layer covering the surface of the cathode material matrix; the cathode material matrix comprises materials with the chemical formula LiNi. x Co y Mn z M 1‑x‑y‑z The O2 material comprises M, which includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si, and W, with a molecular weight of 0.8 ≤ x ≤ 0.92, 0.04 ≤ y ≤ 0.12, 0.04 ≤ z ≤ 0.16, and x + y + z < 1; the coating material comprises one or more oxides of B, Al, Mg, Ti, and W. Compared with traditional high-nickel cathode materials, the above-mentioned high-nickel cathode material exhibits superior rate performance.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery cathode material technology, and in particular to a high-nickel cathode material, preparation method, cathode sheet, battery, and power device. Background Technology

[0002] In recent years, with automakers gradually ceasing the sale of gasoline-powered vehicles and the implementation of carbon neutrality policies in various countries, new energy vehicles equipped with lithium-ion batteries have gradually replaced traditional gasoline-powered vehicles, with hybrid electric vehicles developing particularly rapidly. Compared to pure electric vehicles, hybrid electric vehicles have both a gasoline engine and an electric motor, alleviating consumers' concerns about long driving range and improving safety performance. Compared to traditional gasoline-powered vehicles, hybrid electric vehicles offer superior power performance and comply with national policies. For the cathode materials required for hybrid electric vehicles, a high specific surface area, suitable primary particle size, and appropriate secondary particle size are essential to achieve excellent electrical performance under high-rate conditions.

[0003] To meet the power performance requirements of cathode materials under high capacity conditions, the industry has adopted a variety of measures, such as bulk doping, surface coating modification, and particle size modification. However, facing the increasingly stringent requirements of car manufacturers, single doping and coating methods can no longer meet the needs of end users. It is necessary to develop new solutions from a kinetic perspective to further reduce lithium-ion diffusion resistance, thereby improving the rate performance of cathode materials. Summary of the Invention

[0004] Therefore, it is necessary to provide a high-nickel cathode material, a preparation method, a cathode sheet, a battery, and an electrical device to improve the rate performance of the high-nickel cathode material.

[0005] In a first aspect, this application provides a high-nickel cathode material, wherein the high-nickel cathode material has a hollow structure and includes a cathode material matrix and a coating layer covering the surface of the cathode material matrix;

[0006] The cathode material matrix includes materials with the chemical formula LiNi. x Co y Mn z M 1-x-y-z The material of O2, wherein M includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si and W, 0.8≤x≤0.92, 0.04≤y≤0.12, 0.04≤z≤0.16, and x+y+z<1;

[0007] The coating material includes one or more oxides of B, Al, Mg, Ti, and W.

[0008] In some embodiments, the coating material includes one or more of B2O3, Al2O3, MgO, TiO2, and WO3.

[0009] In some embodiments, the high-nickel cathode material has an average particle size D50 of 3 μm to 5 μm and a specific surface area of ​​0.6 m². 2 / g~1m 2 / g.

[0010] In some embodiments, the diameter of the cathode material substrate is 50% to 80% of the diameter of the high-nickel cathode material.

[0011] A second aspect of this application provides a method for preparing the above-mentioned high-nickel cathode material, comprising the following steps:

[0012] S1. A mixed solution of nickel salt, cobalt salt and manganese salt, a solution of doped element salt and solvent are mixed and then mixed with a surfactant to obtain a mixed solution; the doping element of the doped element salt solution includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si and W;

[0013] S2. The mixed solution, complexing agent and precipitant are subjected to a co-precipitation reaction in a reaction vessel protected by an inert atmosphere. After the reaction is completed, the precipitate is separated and washed and dried in sequence to obtain the precursor.

[0014] S3. The precursor is mixed with lithium salt and subjected to a first calcination treatment in an oxygen-containing atmosphere. After depolymerization and dispersion, the cathode material matrix is ​​obtained.

[0015] S4. The cathode material matrix is ​​mixed with a coating agent and subjected to a second calcination treatment under an oxygen atmosphere to form the coating layer, thereby obtaining the high-nickel cathode material; the coating agent includes one or more oxides of B, Al, Mg, Ti and W.

[0016] In some embodiments, the precursor has an average particle size D50 of 3 μm to 5 μm and a specific surface area of ​​5 m². 2 / g~40m 2 / g.

[0017] In some embodiments, the coprecipitation reaction in step S2 includes a nucleation stage in which nucleation reaction takes place for 20 min to 80 min.

[0018] In some embodiments, the doped element salt solution includes one or more of nitrate solution, sulfate solution, carbonate solution, and phosphate solution;

[0019] Optionally, the concentration of the doped element salt solution is 0.2 mol / L to 3 mol / L.

[0020] In some embodiments, the nickel salt, cobalt salt, and manganese salt mentioned in step S1 each independently include one or more of nitrates, sulfates, and phosphates.

[0021] In some embodiments, the concentrations of nickel salt, cobalt salt, and manganese salt in the mixed metal salt solution in step S1 are each independently 0.2 mol / L to 5 mol / L.

[0022] In some embodiments, the solvent in step S1 includes one or more of water, anhydrous ethanol, and ethylene glycol;

[0023] In some embodiments, the surfactant in step S1 is one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 5000.

[0024] In some embodiments, the complexing agent in step S2 includes one or more of ammonium sulfate and ammonia water.

[0025] In some embodiments, the concentration of the complexing agent in step S2 is 2 mol / L to 6 mol / L.

[0026] In some embodiments, the precipitant in step S2 includes a sodium hydroxide solution.

[0027] In some embodiments, the concentration of the precipitant in step S2 is 2 mol / L to 6 mol / L.

[0028] In some embodiments, the flow rate of the mixed solution in step S2 is 5% to 20% of the total volume of the mixed solution entering the reactor per hour.

[0029] In some embodiments, the pH value of the solution in the reactor during step S2 is 11 to 12.

[0030] In some embodiments, the inert atmosphere in step S2 includes one or more of nitrogen, helium, and argon.

[0031] In some embodiments, the lithium salt in step S3 includes one or more of Li2SO4, Li2CO3, LiNO3, LiCl, LiOH, LiCOOH, and CH3COOLi.

[0032] In some embodiments, the oxygen concentration in the oxygen-containing atmosphere described in step S3 is ≥97%.

[0033] In some embodiments, the process conditions for the first calcination treatment in step S3 include: calcination at 500℃~550℃ for 3h~6h, and calcination at 700℃~750℃ for 10h~16h.

[0034] In some embodiments, the process conditions for the second calcination treatment in step S4 include: calcination temperature of 200℃~400℃ and calcination time of 6h~12h.

[0035] In some embodiments, the molar ratio of nickel in the nickel salt, cobalt in the cobalt salt, and manganese in the manganese salt in step S1 is (80-92):(4-12):(4-16).

[0036] In some embodiments, the mass ratio of the solute in the mixed metal salt solution, the dopant element in the doped element salt solution, the solvent, the complexing agent, and the precipitant in steps S1 and S2 is 1:(0.1-0.5):(1-5):(0.1-1):(0.5-1.5), and the mass of the surfactant accounts for 1% to 10% of the total mass of the solute in the mixed metal salt solution and the doped element salt solution.

[0037] In some embodiments, the molar ratio of the precursor to the lithium salt in step S3 is 1:(1.01 to 1.05).

[0038] In some embodiments, the molar ratio of the positive electrode material matrix to the coating agent in step S4 is 1:(0.01 to 0.5).

[0039] A third aspect of this application provides a positive electrode sheet comprising the above-described high-nickel positive electrode material or the high-nickel positive electrode material prepared by the above-described preparation method.

[0040] A fourth aspect of this application provides a battery comprising the aforementioned positive electrode plate.

[0041] A fifth aspect of this application provides an electrical device including the aforementioned battery.

[0042] Compared with traditional technologies, the above-mentioned high-nickel cathode materials, preparation methods, cathode sheets, batteries, and electrical devices have at least the following advantages:

[0043] The aforementioned coating layer can reduce side reactions between the electrolyte and the high-nickel cathode material, improving the overall performance of the high-nickel cathode material. The high-nickel cathode material has a hollow structure, allowing the electrolyte to not only contact the surface of the high-nickel cathode material but also penetrate into its interior. This increases the contact area between the electrolyte and the high-nickel cathode material, shortens the lithium-ion diffusion path, and simultaneously increases the lithium-ion diffusion channel area, improving the Li-ion efficiency. +The diffusion rate is increased, reducing impedance and thus improving the rate performance and power characteristics of high-nickel cathode materials. Attached Figure Description

[0044] Figure 1 The images are scanning electron microscope (SEM) images of the precursors synthesized in Examples 1-6 and Comparative Examples 1-2 of this application, wherein: (a) Example 1, (b) Example 2, (c) Example 3, (d) Examples 4-6, (e) Comparative Example 1, and (f) Comparative Example 2.

[0045] Figure 2 The images shown are cross-sectional electron microscope images of the precursors synthesized in Examples 1-6 and Comparative Examples 1-2 of this application, wherein: (a) Example 1, (b) Example 2, (c) Example 3, (d) Examples 4-6, (e) Comparative Example 1, and (f) Comparative Example 2.

[0046] Figure 3 Scanning electron microscope (SEM) images of the high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 of this application, wherein: (a) Example 1, (b) Example 2, (c) Example 3, (d) Examples 4-6, (e) Comparative Example 1, and (f) Comparative Example 2.

[0047] Figure 4 The images shown are cross-sectional electron microscope images of the high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 of this application, wherein: (a) Example 1, (b) Example 2, (c) Example 3, (d) Examples 4-6, (e) Comparative Example 1, and (f) Comparative Example 2. Detailed Implementation

[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0049] In this application, unless otherwise defined, all technical terms and jargon not explicitly stated have the same meaning as commonly understood by those skilled in the art and are common knowledge to those skilled in the art. Methods not explicitly stated are all conventional methods known to those skilled in the art. The term "multiple" in this application means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0051] In this application, the use of numerical ranges represented by endpoints includes all numbers within that range as well as any range within that range. For example, 1 to 6 can include 1, 1.2, 1.5, 1.7, 2, 2.6, 3, 3.8, 4, 4.4, 5 or 6, etc., or it can include 1 to 1.2, 1 to 1.7, 2 to 4.4, 3.8 to 5, 4 to 5.5, 5 to 6, etc.

[0052] One embodiment of this application provides a high-nickel cathode material, which has a hollow structure and includes a cathode material matrix and a coating layer covering the surface of the cathode material matrix;

[0053] The cathode material matrix includes materials with the chemical formula LiNi. x Co y Mn z M 1-x-y-z The material of O2, wherein M includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si and W, 0.8≤x≤0.92, 0.04≤y≤0.12, 0.04≤z≤0.16, and x+y+z<1;

[0054] The coating material includes one or more oxides of B, Al, Mg, Ti, and W.

[0055] In the aforementioned high-nickel cathode material, M, as a doping element in the cathode material matrix, plays a role in stabilizing the crystal lattice. The coating layer reduces side reactions between the electrolyte and the high-nickel cathode material, improving the overall performance of the high-nickel cathode material. The high-nickel cathode material has a hollow structure, which facilitates sufficient contact between the electrolyte and it. Specifically, the electrolyte can not only contact the surface of the high-nickel cathode material but also penetrate into its interior, increasing the contact area between the electrolyte and the high-nickel cathode material, shortening the lithium-ion diffusion path, and simultaneously increasing the lithium-ion diffusion channel area, thereby improving the Li-ion performance. + The diffusion rate is reduced, impedance is decreased, and thus rate performance and power characteristics are improved under high capacity conditions. It is understood that the coating material can include one or more of the following: oxides of B, Al, Mg, Ti, and W, such as B₂O₃, Al₂O₃, MgO, TiO₂, WO₃, etc. In this application, the Ni content of the cathode material is 0.8–0.92%. In conventional technology, a Ni content ≥60% in the cathode material is considered a high-nickel cathode material; therefore, the cathode material in this application is a high-nickel cathode material. It is understood that the cathode material matrix can be, for example, LiNi. 0.82 Co 0.11 Mn 0.068 W 0.002 O2, LiNi 0.85 Co 0.08 Mn0.069 Al 0.001 O2, LiNi 0.90 Co 0.05 Mn 0.049 Mg 0.001 O2 and LiNi 0.92 Co 0.04 Mn 0.038 W 0.002 One or more of O2.

[0056] In some embodiments, the coating material includes one or more of B2O3, Al2O3, MgO, TiO2, and WO3.

[0057] In some embodiments, the high-nickel cathode material has an average particle size D50 of 3 μm to 5 μm and a specific surface area of ​​0.6 m². 2 / g~1m 2 / g. It is understandable that the average particle size D50 of the high-nickel cathode material can be, for example, 3μm, 3.5μm, 4μm, 4.5μm, or 5μm, and the specific surface area of ​​the high-nickel cathode material can be, for example, 0.6m². 2 / g, 0.7m 2 / g, 0.8m 2 / g, 0.9m 2 / g or 1m 2 / g etc.

[0058] In some embodiments, the diameter of the cathode material substrate is 50% to 80% of the diameter of the high-nickel cathode material. It is understood that the diameter of the cathode material substrate can be, for example, 50%, 55%, 60%, 65%, 70%, 75%, or 80% of the diameter of the high-nickel cathode material, or other values ​​between 50% and 80%.

[0059] Another embodiment of this application provides a method for preparing the above-mentioned high-nickel cathode material, including the following steps:

[0060] S1. A mixed solution of nickel salt, cobalt salt and manganese salt, a solution of doped element salt and solvent are mixed and then mixed with a surfactant to obtain a mixed solution; the doping element of the doped element salt solution includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si and W;

[0061] S2. The mixed solution, complexing agent and precipitant are co-precipitated in a reaction vessel under an inert atmosphere. After the reaction is complete, the precipitate is separated, washed and dried in sequence to obtain the precursor.

[0062] S3. The precursor is mixed with lithium salt and subjected to a first calcination treatment in an oxygen-containing atmosphere. After depolymerization and dispersion, the cathode material matrix is ​​obtained.

[0063] S4. The cathode material matrix is ​​mixed with the coating agent and subjected to a second calcination treatment under an oxygen atmosphere to form a coating layer, thereby obtaining a high-nickel cathode material; the coating agent includes one or more oxides of B, Al, Mg, Ti and W.

[0064] The aforementioned nickel salt, cobalt salt, manganese salt, and dopant elements are mixed in a salt solution, which facilitates the uniform distribution of nickel, cobalt, manganese, and dopant elements in the precursor. The precursor is prepared through a co-precipitation reaction in a reactor, exhibiting a loose internal and dense external structure. After the first calcination treatment, the primary particles inside the precursor shrink outwards, forming a cathode material matrix with a clearly defined porous structure in the center of the particles. Coating the cathode material matrix with a coating agent results in high-nickel cathode material particles that still possess a clearly defined porous structure. The reduced side reactions between the coated high-nickel cathode material and the electrolyte improve the overall performance of the high-nickel cathode material. The hollow structure of the high-nickel cathode material facilitates sufficient contact with the electrolyte. Specifically, the electrolyte can not only contact the surface of the high-nickel cathode material but also penetrate into its interior, increasing the contact area between the electrolyte and the high-nickel cathode material, shortening the lithium-ion diffusion path, and simultaneously increasing the lithium-ion diffusion channel area, thereby improving the Li-N-C ... + The diffusion rate is increased, reducing impedance and thus improving rate performance and power characteristics under high capacity conditions.

[0065] In some embodiments, the precursor has an average particle size D50 of 3 μm to 5 μm and a specific surface area of ​​5 m². 2 / g~40m 2 / g. It is understood that the average particle size D50 of the precursor can be, for example, 3μm, 3.2μm, 3.4μm, 3.6μm, 3.8μm, 4μm, 4.2μm, 4.4μm, 4.6μm, 4.8μm, or 5μm, etc.; the specific surface area of ​​the precursor can be 5m². 2 / g~40m 2 Any value between / g, for example: 5m 2 / g, 10m 2 / g, 15m 2 / g、20m 2 / g、25m 2 / g、30m 2 / g、35m 2 / g or 40m 2 / g etc.

[0066] In some embodiments, the coprecipitation reaction in step S2 includes a nucleation stage for nucleation, with a nucleation reaction time of 20 min to 80 min. It is understood that the nucleation reaction time can be any value between 20 min and 80 min, such as 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, or 80 min, etc.; specifically, the coprecipitation reaction also includes a whisker growth stage, which follows the nucleation stage.

[0067] In some embodiments, the doped element salt solution in step S1 includes one or more of nitrate solution, sulfate solution, carbonate solution and phosphate solution.

[0068] In some embodiments, the concentration of the doped element salt solution in step S1 is 0.2 mol / L to 3 mol / L. It is understood that the concentration of the doped element salt solution in step S1 can be, for example, 0.2 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, or 3 mol / L.

[0069] In some embodiments, the nickel salt, cobalt salt, and manganese salt in step S1 each independently include one or more of nitrates, sulfates, and phosphates.

[0070] In some embodiments, the concentrations of nickel, cobalt, and manganese salts in the mixed metal salt solution in step S1 are each independently 0.2 mol / L to 5 mol / L. It is understood that the concentration of nickel salt in the mixed metal salt solution can be, for example, 0.2 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L; the concentration of cobalt salt in the mixed metal salt solution can be, for example, 0.2 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L; and the concentrations of nickel, cobalt, and manganese salts in the mixed metal salt solution can be the same or different.

[0071] In some embodiments, the solvent in step S1 includes one or more of water, anhydrous ethanol, and ethylene glycol. Water may be, for example, deionized water, distilled water, etc.

[0072] In some embodiments, in step S1, the precipitate is separated by centrifugation. The centrifugation time is 5 min to 20 min, the washing time is 10 min to 30 min, the drying temperature is 100℃ to 150℃, and the drying time is 120 min to 180 min. It is understood that the centrifugation time can be, for example, 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, or 20 min; the washing time can be, for example, 10 min, 15 min, 20 min, 25 min, or 30 min; the drying temperature can be, for example, 100℃, 110℃, 120℃, 130℃, 140℃, or 150℃; and the drying time can be, for example, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, or 180 min.

[0073] In some embodiments, the surfactant in step S1 is one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 5000.

[0074] In some embodiments, the complexing agent in step S2 includes one or more of ammonium sulfate and ammonia water.

[0075] In some embodiments, the concentration of the complexing agent in step S2 is 2 mol / L to 6 mol / L. It is understood that the concentration of the complexing agent in step S2 can be, for example, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, 5.5 mol / L, or 6 mol / L.

[0076] In some embodiments, the precipitant in step S2 includes a sodium hydroxide solution. Specifically, the concentration of the precipitant is 2 mol / L to 6 mol / L. It is understood that the concentration of the precipitant can be, for example, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, or 6 mol / L.

[0077] In some embodiments, the flow rate of the mixed solution in step S2 is 5% to 20% of the total volume of the mixed solution entering the reactor per hour. It is understood that the volume of the mixed solution entering the reactor per hour can be, for example, 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, or 20% of the total volume of the reactor.

[0078] In some embodiments, the pH value of the solution in the reactor during step S2 is 11 to 12. It is understood that the pH value of the solution in the reactor during step S2 may be, for example, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, or 12.

[0079] In some embodiments, the inert atmosphere in step S2 includes one or more of nitrogen, helium, and argon.

[0080] In some embodiments, the lithium salt in step S3 includes one or more of Li2SO4, Li2CO3, LiNO3, LiCl, LiOH, LiCOOH (lithium formate), and CH3COOLi (lithium acetate).

[0081] In some embodiments, the oxygen concentration in the oxygen-containing atmosphere during step S3 is ≥97%. It is understood that the oxygen concentration can be, for example, 97%, 97.2%, 97.5%, 97.8%, 98%, 98.2%, 98.5%, 98.8%, 99%, 99.2%, 99.4%, 99.6%, or 99.9%, etc.

[0082] In some embodiments, the process conditions for the first calcination treatment in step S3 include: calcination at 500℃~550℃ for 3h~6h, and calcination at 700℃~750℃ for 10h~16h. It can be understood that calcination at 500℃~550℃ for 3h~6h can be, for example, 500℃, 505℃, 510℃, 515℃, 520℃, 525℃, 530℃, 535℃, 540℃, 545℃, or 550℃, and the calcination time can be any value between 3h and 6h, for example: 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, or 6h, etc.; calcination at 700℃~750℃ for 10h~16h... h, wherein the roasting temperature can be, for example, 700℃, 705℃, 710℃, 715℃, 720℃, 725℃, 730℃, 735℃, 740℃, 745℃ or 750℃, etc., and the roasting time can be any value between 10h and 16h, for example: 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h, 15h, 15.5h or 16h, etc.

[0083] In some implementations, the depolymerization equipment in step S3 includes one or more of a mechanical mill and an air jet mill.

[0084] In some embodiments, the process conditions for the second calcination treatment in step S4 include: a calcination temperature of 200℃ to 400℃ and a calcination time of 6h to 12h. It is understood that the calcination temperature can be, for example, 200℃, 220℃, 250℃, 280℃, 300℃, 320℃, 350℃, 380℃, or 400℃, and can also be other values ​​between 200℃ and 400℃. The calcination time can be, for example, 6h, 7h, 8h, 9h, 10h, 11h, or 12h, and can also be other values ​​between 6h and 12h.

[0085] In some embodiments, the molar ratio of nickel in the nickel salt, cobalt in the cobalt salt, and manganese in the manganese salt in step S1 is (80-92):(4-12):(4-16). It is understood that the molar ratio of nickel in the nickel salt, cobalt in the cobalt salt, and manganese in the manganese salt in step S1 can be, for example, 80:4:16, 80:12:8, 88:8:4, or 92:4:4, etc.

[0086] In some embodiments, the mass ratio of solute in the mixed metal salt solution, dopant in the doped element salt solution, solvent, complexing agent, and precipitant in steps S1 and S2 is 1:(0.1-0.5):(1-5):(0.1-1):(0.5-1.5), and the mass percentage of the surfactant in the mixed metal salt solution and the doped element salt solution is 1% to 10% of the total mass of the solute. It is understood that the mass ratio of solute in the mixed metal salt solution, dopant in the doped element salt solution, solvent, complexing agent, and precipitant in steps S1 and S2 can be, for example, 1:0.1:1:0.1:0.5, 1:0.2:3:0.3:1, or 1:0.5:5:1:1.5, etc.; and the mass percentage of the surfactant in the mixed metal salt solution and the doped element salt solution can be, for example, 1%, 4%, 6%, 8%, or 10%, etc.

[0087] In some embodiments, the molar ratio of the precursor to the lithium salt in step S3 is 1:(1.01 to 1.05). It is understood that the molar ratio of the precursor to the lithium salt in step S3 can be, for example, 1:1.01, 1:1.02, 1:1.03, 1:1.035, 1:1.04, 1:1.045, 1:1.05, etc.

[0088] In some embodiments, the molar ratio of the cathode material matrix to the coating agent in step S4 is 1:(0.01 to 0.5). It is understood that the molar ratio of the cathode material matrix to the coating agent in step S4 can be, for example, 1:0.01, 1:0.1, 1:0.2, 1:0.3, 1:0.4, or 1:0.5, etc.

[0089] Another embodiment of this application provides a positive electrode sheet, comprising the above-described high-nickel positive electrode material or the high-nickel positive electrode material prepared by the above-described preparation method. The above-described high-nickel positive electrode material can, for example, be mixed with a conductive agent, a binder, and a solvent to form a slurry, which is then coated onto an aluminum foil and dried to obtain the positive electrode sheet. This application does not impose any particular limitation on the above-described conductive agent, binder, and solvent; commonly used materials in the art can be used. The above-described conductive agent may include, but is not limited to, one or more of graphene, carbon nanotubes, carbon fibers, conductive carbon black, and graphene quantum dots; the above-described binder may include, but is not limited to, one or more of sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and polyacrylic acid (PAA); and the above-described solvent may include, but is not limited to, one or more of N-methylpyrrolidone (NMP) and water.

[0090] Another embodiment of this application provides a battery including the above-described positive electrode sheet. The positive electrode sheet can be used in batteries, including but not limited to lithium-ion batteries, lithium metal batteries, or solid-state batteries. For example, when used in a lithium-ion battery, the positive electrode sheet can be used in conjunction with a negative electrode sheet and a separator, and assembled with a battery casing after winding or stacking, followed by electrolyte injection and encapsulation to obtain the battery.

[0091] Another embodiment of this application provides an electrical device including the aforementioned battery. The battery can be used as a power source or energy storage unit in the aforementioned electrical device, which includes, but is not limited to, electric vehicles, electric bicycles, smart home appliances, mobile phones, computers, tablets, or communication base station power boxes.

[0092] The present application will be further illustrated below through examples and comparative examples.

[0093] Example 1

[0094] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0095] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, and then add polyethylene glycol 400 surfactant accounting for 6% of the total mass of the solutes in the mixed metal salt solution and sodium tungstate solution to obtain a mixed solution.

[0096] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.57 μm, and the BET is 30 μm. 2 / g;

[0097] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 4 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.068 W 0.002 O2 materials;

[0098] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0099] Example 2

[0100] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0101] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, and then add polyethylene glycol 400 surfactant accounting for 3% of the total mass of the solutes in the mixed metal salt solution and sodium tungstate solution to obtain a mixed solution.

[0102] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.62 μm, and the BET is 20 μm. 2 / g;

[0103] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 3 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.068 W 0.002 O2 materials;

[0104] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0105] Example 3

[0106] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0107] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, and then add polyethylene glycol 400 surfactant accounting for 1% of the total mass of the solutes in the mixed metal salt solution and sodium tungstate solution to obtain a mixed solution.

[0108] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.58 μm, and the BET is 10 μm. 2 / g;

[0109] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 3 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.068 W 0.002 O2 materials;

[0110] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0111] Example 4

[0112] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0113] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, add aluminum hydroxide accounting for 1% of the total mass of the mixed metal salt solution, and then add polyethylene glycol 400 surfactant accounting for 3% of the total mass of the solutes in the mixed metal salt solution, sodium tungstate solution, and aluminum hydroxide to obtain a mixed solution.

[0114] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.60 μm, and the BET is 30 μm. 2 / g;

[0115] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 4 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.10 Mn 0.068 W 0.002 Al 0.001 O2 materials;

[0116] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0117] Example 5

[0118] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0119] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, then add aluminum hydroxide accounting for 1% of the total mass of the mixed metal salt solution, and finally add polyethylene glycol 400 surfactant accounting for 3% of the total mass of the solutes in the mixed metal salt solution, sodium tungstate solution, and aluminum hydroxide to obtain a mixed solution.

[0120] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.55 μm, and the BET is 30 μm. 2 / g;

[0121] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 4 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.067 W 0.002 Al 0.001 O2 materials;

[0122] S4. The cathode material matrix and the coating agent B2O3 are mixed uniformly in a molar ratio of 1:0.03 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes B2O3.

[0123] Example 6

[0124] The high-nickel cathode material in this embodiment is prepared according to the following method:

[0125] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, then add aluminum hydroxide accounting for 1% of the total mass of the mixed metal salt solution, and finally add polyethylene glycol 400 surfactant accounting for 3% of the total mass of the solutes in the mixed metal salt solution, sodium tungstate solution, and aluminum hydroxide to obtain a mixed solution.

[0126] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.68 μm, and the BET is 30 μm. 2 / g;

[0127] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 4 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.067 W 0.002 Al 0.001 O2 materials;

[0128] S4. The cathode material matrix and the coating agent Al2O3 are mixed uniformly in a molar ratio of 1:0.01 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes Al2O3.

[0129] Comparative Example 1

[0130] The high-nickel cathode material in this comparative example was prepared according to the following method:

[0131] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add sodium tungstate solution accounting for 2% of the total mass of the mixed metal salt solution, and then add aluminum hydroxide accounting for 1% of the total mass of the mixed metal salt solution to obtain the mixed solution.

[0132] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.50 μm, and the BET is 8 μm. 2 / g;

[0133] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 4 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.84 μm, which includes LiNi 0.82 Co 0.10 Mn 0.068 W 0.002 Al 0.001 O2 materials;

[0134] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0135] Comparative Example 2

[0136] The high-nickel cathode material in this comparative example was prepared according to the following method:

[0137] S1. Prepare a 2 mol / L mixed metal salt solution by dissolving nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of 82:11:7. Add 3% (by mass) of the surfactant polyethylene glycol 400 to the mixed metal salt solution to obtain the mixed solution.

[0138] S2. Prepare a 3 mol / L sodium hydroxide solution as a precipitant and a 5 mol / L ammonia solution as a complexing agent. Add 115 g of the mixed solution, 120 g of sodium hydroxide solution, and 175 g of ammonia solution to a nitrogen-protected reactor for co-precipitation. The volume of the mixed metal salt solution entering the reactor per hour is 10% of the total reactor volume. Adjust the pH to 11.5, the nucleation reaction time is 30 min, and the total reaction time is 20 h. After the reaction, the material is centrifuged to separate the precipitate. Then, the precipitate is washed and dried sequentially to obtain a precursor with a loose internal structure and a dense external structure. The centrifugation time is 8 min, the washing time is 15 min, the drying temperature is 120℃, and the drying time is 120 min. The average particle size D50 of the precursor is 3.58 μm, and the BET is 20 μm. 2 / g;

[0139] S3. The precursor and LiOH were mixed uniformly at a molar ratio of 1:1.03, and then calcined in a kiln with an oxygen concentration of 99.9% in stages. First, the temperature was raised to 500℃ and held for 3 hours, then the temperature was raised to 750℃ and held for 16 hours. The mixture was then depolymerized and dispersed using a pulverizer to obtain a cathode material matrix with an average particle size D50 of 3.8 μm, which includes LiNi 0.82 Co 0.11 Mn 0.07 O2 materials;

[0140] S4. The cathode material matrix and the coating agent WO3 are mixed uniformly in a molar ratio of 1:0.02 and sintered at 300°C for 12 hours under conditions of 95% oxygen concentration to obtain a high-nickel cathode material, wherein the coating material includes WO3.

[0141] The precursors and their cross-sections prepared in Examples 1-6 and Comparative Examples 1-2, as well as the high-nickel cathode materials and their cross-sections, were observed using scanning electron microscopy. The results are as follows: Figures 1-4 As shown.

[0142] Figure 1 (a)~ Figure 1 (f) are scanning electron microscope images of the precursors synthesized in Examples 1-6 and Comparative Examples 1-2 of this application at a magnification of 10000x, wherein... Figure 1 (a)~ Figure 1 The scale length in (f) is 1 μm.

[0143] Figure 2 (a) Figure 2 (b) and Figure 2 (d)~ Figure 2 (f) is a scanning electron microscope image at 10,000x magnification of the cross-section of the precursors synthesized in Examples 1-2, 4-6 and Comparative Examples 1-2 of this application. Figure 2(c) is a scanning electron microscope image of the cross-section of the precursor synthesized in Example 3 of this application at a magnification of 8000x, wherein... Figure 2 (a) Figure 2 (b) and Figure 2 (d)~ Figure 2 The scale length in (f) is 1 μm. Figure 2 The scale length in (c) is 2μm.

[0144] Figure 3 (a)~ Figure 3 (f) are scanning electron microscope (SEM) images of the high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 of this application at a magnification of 10,000. Figure 3 (a)~ Figure 3 The scale length in (f) is 1 μm.

[0145] Figure 4 (a)~ Figure 4 (f) is a scanning electron microscope (SEM) image at 10,000x magnification of the cross-section of the high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 of this application. Figure 4 (a)~ Figure 4 The scale length in (f) is 1 μm.

[0146] The specific surface area and particle size of the precursors and high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0147] The high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 were used as active materials, acetylene black as conductive agent, PVDF as binder, and NMP as solvent. They were mixed evenly at a mass ratio of 90:5:5 to form a slurry. The slurry was coated on aluminum foil and dried in a vacuum drying oven at 100°C for 15 hours. After drying, the slicing was used to cut the cathode sheets with a diameter of 12 mm. Button batteries were assembled in a glove box. The electrolyte was 1 mol / L LiPF6 dissolved in EC+DEC (mass ratio of 1:1). After the batteries were assembled, they were allowed to stand for 12 hours. The first charge-discharge, cycle performance, and rate performance tests of the batteries were conducted using the Blue Electric Test System. The results are shown in Table 2.

[0148] Test conditions for initial charge / discharge and initial coulombic efficiency: voltage range 2.5V–4.25V, 0.2C constant current charging, 0.2C constant current discharging. Test conditions for cycle performance: voltage range 3V–4.3V, 0.5C constant current charging, 0.5C constant current discharging, 50 cycles, capacity retention = (discharge specific capacity at cycle 50 / discharge specific capacity at cycle 1) × 100%. Test conditions for rate performance: charge / discharge at 0.1C, 0.5C, 1C, 1.5C, and 2C.

[0149] Table 1

[0150]

[0151] Table 2

[0152]

[0153]

[0154] Note: In Table 2, 0.5C / 0.1C represents the specific discharge capacity of the battery under 0.5C conditions / the specific discharge capacity under 0.1C conditions.

[0155] Depend on Figures 1-4 It can be seen that the precursors and high-nickel cathode materials prepared in Examples 1-6 and Comparative Examples 1-2 all have spherical structures, while the precursors prepared in Examples 1-6 and Comparative Example 2 have loose internal structures. Figure 2 The area indicated by the dashed circle represents the location of the loose precursor, due to... Figure 2 (a) and Figure 2 (b) The loose structure is more obvious (not indicated by a dashed circle), while the precursor prepared in Comparative Example 1 has a more dense internal structure; the high-nickel cathode materials prepared in Examples 1-6 and Comparative Example 2 have a hollow structure, while the high-nickel cathode material prepared in Comparative Example 1 has a solid structure.

[0156] From Tables 1-2 and Figures 1-4 It can be seen that:

[0157] Compared with Comparative Examples 1-2, Examples 1-6 all prepared precursors with porous internal structures. Examples 1 and 4-6 had the largest specific surface area and a larger porous area. Examples 2 and 3 had progressively smaller specific surface areas and progressively smaller porous internal areas. From the perspective of electrochemical performance analysis, the discharge specific capacity and cycle retention rate of the high-nickel cathode materials prepared in Examples 1-3 decreased progressively. Compared with Examples 4, Example 4 had a slightly lower capacity but a higher cycle retention rate. Compared with Examples 4-6, the coating of element B was beneficial to improving ionic conductivity. Example 5 had the best overall performance.

[0158] The difference between Example 4 and Comparative Example 1 is that the surfactant polyethylene glycol 400 was not added in step S1 of Comparative Example 1, and the precursor of Comparative Example 1 has a dense internal structure with a specific surface area of ​​only 8 m². 2 / g, after being sintered into a high-nickel cathode material, has no obvious internal pores and its overall performance is poor.

[0159] The difference between Example 2 and Comparative Example 2 is that the precursor of Comparative Example 2 has no doped elements added. The precursors prepared in both Example 2 and Comparative Example 2 have a loose internal structure and good rate performance. The precursor doped with W in Example 2 is used to prepare a high-nickel cathode material, and its cycle performance is significantly better than that of Comparative Example 2.

[0160] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0161] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a high-nickel cathode material, characterized in that, The high-nickel cathode material has a hollow structure and includes a cathode material matrix and a coating layer covering the surface of the cathode material matrix. The cathode material matrix includes materials with the chemical formula LiNi. x Co y Mn z M 1-x-y-z The material of O2, wherein M includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si and W, 0.8≤x≤0.92, 0.04≤y≤0.12, 0.04≤z≤0.16, and x+y+z<1; The coating material includes one or more oxides of B, Al, Mg, Ti, and W; The specific surface area of ​​the high-nickel cathode material is 0.6 m². 2 / g~1m 2 / g, wherein the diameter of the cathode material substrate is 50% to 80% of the diameter of the high-nickel cathode material; The preparation method of the high-nickel cathode material includes the following steps: S1. A mixed metal salt solution of nickel, cobalt, and manganese salts, a doped element salt solution, and a solvent are mixed, and then mixed with a surfactant to obtain a mixed solution; the doped element salt solution includes one or more of Zr, Mg, Ti, Te, Sb, Ca, Si, and W; the surfactant includes one or more of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 5000; the mass percentage of the surfactant in the mixed metal salt solution and the doped element salt solution is 3% to 6% of the total mass of the solutes; S2. The mixed solution, complexing agent, and precipitant are subjected to a co-precipitation reaction in a reactor protected by an inert atmosphere. After the reaction is completed, the precipitate is separated, washed, and dried sequentially to obtain the precursor. The co-precipitation reaction includes a nucleation stage, and the nucleation reaction time is 20 min to 80 min. The average particle size D50 of the precursor is 3 μm to 5 μm, and the specific surface area is 5 m². 2 / g~40m 2 / g; the pH value of the solution in the reactor is 11~12; S3. The precursor is mixed with lithium salt and subjected to a first calcination treatment in an oxygen-containing atmosphere. After depolymerization and dispersion, the cathode material matrix is ​​obtained. The process conditions for the first calcination treatment include: calcination at 500℃~550℃ for 3h~6h, and calcination at 700℃~750℃ for 10h~16h. S4. The cathode material matrix is ​​mixed with a coating agent and subjected to a second calcination treatment under an oxygen atmosphere to form the coating layer, thereby obtaining the high-nickel cathode material; the coating agent includes one or more oxides of B, Al, Mg, Ti and W.

2. The preparation method according to claim 1, characterized in that, The coating material includes one or more of B2O3, Al2O3, MgO, TiO2, and WO3.

3. The preparation method according to any one of claims 1 to 2, characterized in that, The average particle size D50 of the high-nickel cathode material is 3μm~5μm.

4. The preparation method according to any one of claims 1 to 2, characterized in that, The average particle size D50 of the high-nickel cathode material is 3μm~4μm.

5. The preparation method according to any one of claims 1 to 2, characterized in that, The specific surface area of ​​the high-nickel cathode material is 0.6 m². 2 / g~0.8m 2 / g.

6. The preparation method according to any one of claims 1 to 2, characterized in that, The nucleation reaction time is 30 min to 80 min.

7. The preparation method according to any one of claims 1 to 2, characterized in that, The preparation method includes at least one of the following features (1) to (14): (1) The doped element salt solution mentioned in step S1 includes one or more of nitrate solution, sulfate solution, carbonate solution and phosphate solution; (2) The concentration of the doped element salt solution is 0.2 mol / L to 3 mol / L; (3) The nickel salt, cobalt salt, and manganese salt mentioned in step S1 each independently include one or more of nitrates, sulfates, and phosphates; (4) The concentrations of nickel salt, cobalt salt and manganese salt in the mixed metal salt solution mentioned in step S1 are each 0.2 mol / L to 5 mol / L independently; (5) The solvent mentioned in step S1 includes one or more of water, anhydrous ethanol and ethylene glycol; (6) The complexing agent mentioned in step S2 includes one or more of ammonium sulfate and ammonia water; (7) The concentration of the complexing agent mentioned in step S2 is 2 mol / L to 6 mol / L; (8) The precipitant mentioned in step S2 includes a sodium hydroxide solution; (9) The concentration of the precipitant mentioned in step S2 is 2 mol / L to 6 mol / L; (10) The flow rate of the mixed solution in step S2 is 5% to 20% of the total volume of the mixed solution entering the reactor per hour; (11) The inert atmosphere mentioned in step S2 includes one or more of nitrogen, helium and argon; (12) The lithium salt mentioned in step S3 includes one or more of Li2SO4, Li2CO3, LiNO3, LiCl, LiOH, LiCOOH and CH3COOLi; (13) The oxygen concentration in the oxygen-containing atmosphere described in step S3 is ≥97%; (14) The process conditions for the second roasting treatment in step S4 include: roasting temperature of 200℃~400℃ and roasting time of 6h~12h.

8. The preparation method according to any one of claims 1 to 2, characterized in that, The preparation method includes at least one of the following features (1) to (4): (1) The molar ratio of nickel in the nickel salt, cobalt in the cobalt salt and manganese in the manganese salt in step S1 is (80~92):(4~12):(4~16). (2) The mass ratio of the solute in the mixed metal salt solution, the dopant element in the doped element salt solution, the solvent, the complexing agent, and the precipitant in steps S1 and S2 is 1:(0.1~0.5):(1~5):(0.1~1):(0.5~1.5). (3) The molar ratio of the precursor to the lithium salt in step S3 is 1:(1.01~1.05). (4) The molar ratio of the positive electrode material matrix to the coating agent in step S4 is 1: (0.01~0.5).

9. A positive electrode plate, characterized in that, The high-nickel cathode material prepared by the preparation method according to any one of claims 1 to 8.

10. A battery, characterized in that, Includes the positive electrode sheet as described in claim 9.

11. An electrical appliance, characterized in that, Includes the battery as described in claim 10.

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