Multilayer annular-pore nickel-cobalt aluminum precursor, method for producing it, and cathode material thereof

Abstract

The present invention discloses a multi-layer annular pore nickel-cobalt-aluminum precursor and a preparation method thereof, and a positive electrode material thereof, in which the D50 of the precursor is 8-20μm, the cross-sectional view shows that the spherical secondary particle structure has multi-layer annular pores, and the average porosity value of the cross-section of one particle or a plurality of particles is 6-14%. The nickel-cobalt mixed salt solution, the alkali aluminum solution, the complexing agent, and the precipitating agent are co-precipitated, and the pH value and the aluminum solution concentration at each stage are strictly controlled, followed by solid-liquid separation, washing, oven drying, uniform mixing, sieving, and demagnetization processes to prepare a nickel-cobalt-aluminum precursor having multi-layer annular pores. The loose and porous morphology of the precursor is conducive to mixing and sintering lithium to obtain a positive electrode material. The positive electrode material has a multi-layer lithium ion diffusion path, which can buffer the mechanical distortion force of the crystal lattice generated in the material during charging and discharging, and improve the cycle. It has a high initial discharge specific capacity, low internal resistance, good rate performance, and good cycle stability.

Description

Cross-reference to Related Applications

[0001] This application claims priority based on a Chinese application with a CN application number of 202211319408.6 and a filing date of October 26, 2022, and the disclosure content of this CN application is incorporated into this application as a whole again.

Technical Field

[0002] The present invention belongs to the field of cathode material technology for lithium batteries, and specifically relates to a multi-layered annular pore nickel cobalt aluminum precursor, its manufacturing method, and its cathode material.

Background Art

[0003] At present, the popularization and development of electric vehicles are restricted by problems such as insufficient cruising range, slow charging speed, and slightly too high cost in power batteries, and the market penetration rate of electric vehicles is greatly affected by the cost-effectiveness of power lithium batteries. The cathode material is the core key material of power lithium batteries. The high energy density of the cathode material is closely related to the cruising range of electric vehicles, and since its cost accounts for about 1 / 3 of the cost of lithium battery cells, the development of high energy density, long life, high safety, and low cost cathode materials is extremely important for the large-scale commercialization of power lithium batteries and electric vehicles.

[0004] Since the NCA material combines the advantages of LiNiO2 and LiCoO2, it has a high reversible specific capacity, not only a low material cost, but also enhanced structural stability and safety of the material after doping with aluminum. Furthermore, it improves the cycle stability of the material. Therefore, the NCA material is one of the most popular materials in the research of currently commercialized cathode materials.

[0005] The technical solution disclosed in the patent with publication number CN113651372A involves producing a precursor with high sphericity and no twinned particles using a discontinuous method. This solution only improves the morphology of the precursor surface and makes no mention of the internal spatial structure of the precursor, and therefore cannot effectively explain the advantages of sintering the precursor into a cathode material.

[0006] The technical solution disclosed in the patent with publication number CN113697870B provides a dinuclear twinned precursor for improving lithium ion diffusion pathways and lithium ion diffusion rates. However, as seen from a provided cross-sectional electron microscope, the precursor has a dense internal structure, making it unsuitable for mixing and sintering with lithium salts, forming multiple lithium ion diffusion pathways, and making it unsuitable for elements modified by the coating to enter the surface of primary particles. Therefore, the technical solution also fails to highlight the advantages of the improved precursor. [Overview of the project] [Problems that the invention aims to solve]

[0007] Based on the above problems, the present invention, during research on nickel-cobalt-aluminum precursors, has found that by utilizing the fact that the solubility product constants between elements differ during production, it is possible to directly improve the morphology and porosity of primary particles in the internal structure of precursor particles by strictly controlling the pH and concentration of the aluminum solution at each reaction step. This method is simple, inexpensive, and suitable for industrial production, and the resulting product has good performance after sintering. [Means for solving the problem]

[0008] The present invention relates to a multilayer annular-pore nickel-cobalt aluminum precursor, wherein the chemical formula is Ni M Co N Al 1-M-NThe present invention provides a multilayer annular-pore nickel-cobalt-aluminum precursor characterized by (OH)2 having 0.8≦M≦0.97, 0.02≦N≦0.09, and 0.01≦1-MN≦0.055, where D50 is 8~20μm, and the spherical secondary particle structure of the precursor has multilayer annular pores, and the porosity value, which is the cross-sectional average value of one or more spherical secondary particles, is 6~14%.

[0009] The present invention further provides a method for producing the above-mentioned precursor, S1 involves weighing nickel sulfate and cobalt sulfate powder and dissolving them in pure water to prepare a nickel-cobalt mixed salt solution. S2 involves weighing the aluminum salt and adding it to the sodium hydroxide solution to prepare an alkali aluminum solution. S3 involves pumping the nickel-cobalt mixed salt solution S1, the alkali-aluminum solution S2, and the complexing agent simultaneously into a reaction vessel to carry out a stepwise coprecipitation reaction. After the reaction is complete, the material obtained from the reaction is subjected to solid-liquid separation, washing, oven drying, homogeneous mixing, sieving, and demagnetization to obtain a nickel-cobalt-aluminum precursor, which includes S4.

[0010] Furthermore, in step S1, the total metal ion concentration of the nickel-cobalt mixed salt solution is 1.0 to 2.0 mol / L.

[0011] Furthermore, in step S2, the aluminum salt is sodium metaaluminate, and the Al in the alkali aluminum solution 3+ The concentration is 0.1 to 0.5 mol / L, and the molar concentration of the sodium hydroxide solution is 5 to 10 mol / L.

[0012] Furthermore, in step S3, the concentration of the complexing agent is 10 to 15 mol / L, and the complexing agent is at least one of EDTA, aqueous ammonia, ammonium carbonate, and ammonium bicarbonate.

[0013] Furthermore, in step S3, the coprecipitation reaction is carried out in four stages: the first stage involves growing the nuclei from the formation of the nuclei to a D150 where 25% ≤ D150 < 40% of the target value; the second stage involves growing the spherical secondary particles to a D250 where 40% ≤ D250 < 60% of the target value; the third stage involves growing the spherical secondary particles to a D350 where 60% ≤ D350 < 90% of the target value; and the fourth stage involves immediately stopping the growth reaction once the spherical secondary particles have grown to the target value. In each stage, the flow rate of the nickel-cobalt mixed salt solution is 1 to 3.5 L / h, the flow rate of the alkali-aluminum solution is 1 to 2 L / h, and the flow rate of the complexing agent is 0.5 to 1.5 L / h, the pH is controlled to 10 to 12, the reaction temperature in each stage is controlled to 55 to 70°C, and the stirring speed in each stage is 500 to 1000 rpm.

[0014] Furthermore, in step S4, the washing is specifically carried out by first washing the material obtained from the reaction with an alkaline solution, and then washing it with deionized water at 25-80°C, wherein the resistivity of the washing water after washing is less than 0.02 cm / μs, the alkaline solution is at least one of sodium carbonate solution and sodium hydroxide solution, and the molar concentration of the alkaline solution is 4.0-5.0 mol / L.

[0015] The present invention provides a method for manufacturing a positive electrode material for a lithium-ion battery. After obtaining a nickel-cobalt-aluminum precursor using the above manufacturing method, the obtained precursor is uniformly mixed with a lithium source and additives, and then primary sintering, crushing, grinding, washing with water and oven drying, coating, secondary sintering, and sieving are performed to obtain the positive electrode material.

[0016] Furthermore, the lithium source is at least one of lithium hydroxide, lithium nitrate, and lithium chloride; the additive is one or more of the elements Zr, Sr, Ti, W, Mg, Y, La, B, and F; the coating agent used during coating is one or more of element D-containing oxides and element D-containing lithium compounds, where element D is one or more of Co, Li, B, W, Ti, Ce, and Zr; the molar ratio of Ni+CO+Al:Li is 1:1.01~1.05; and the mass ratio of the additive used to the total mass of the precursor and lithium salt is 0.1%~2%. During primary sintering, calcination was performed in an oxygen atmosphere furnace at a calcination temperature of 650~800°C for a calcination time of 10~15h, with an oxygen content of 85%~95% in the atmosphere furnace to obtain the primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, where the mass ratio of primary sintered substrate to water was 1:1 to 3, and the temperature of the deionized water was 20 to 30°C. The substrate was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate and the coating agent were uniformly mixed, where the mass ratio of coating agent to dried substrate was 0.01 to 5%. Subsequently, secondary sintering was performed, and the material was calcined in an oxygen atmosphere furnace at a calcination temperature of 500 to 700°C for a calcination time of 6 to 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain the cathode material.

[0017] The present invention further provides a positive electrode material for a lithium-ion battery obtained by the above manufacturing method. [Effects of the Invention]

[0018] The beneficial effects of this invention are as follows: 1. NCA cathode material has a higher energy density compared to conventional cathode materials LiNiO2 and LiCoO2, and Al 3+ and Co 3+ This refers to atoms with the same valence and similar ionic radii (Al 3+ The ionic radius of is 0.535 Å, and Co 3+has an ionic radius of 0.545 Å). However, since the bonding energy of the Al-O covalent bond is stronger, doping with Al can reduce the mixing and arrangement of lithium and nickel, which is advantageous for stabilizing the structure of the material. Also, Al 3+ doping is not only advantageous for the transfer of heat generated by the decomposition of the electrolyte, but also reduces the oxidation ability of the material with respect to the electrolyte, improving the thermal stability of the material. However, the manufacturing process of the NCA precursor is highly technically difficult. The pH values at which the elements Ni, Co, and Al precipitate are very different, and their solubility product constants are 10 -16 for nickel hydroxide, 10 -14.9 for cobalt hydroxide, and 10 -33 for aluminum hydroxide. Al(OH)3 is an amphoteric hydroxide, and precipitation is likely to occur at low pH values and it is likely to decompose into AlO2 -1 at high pH values. The present invention can manufacture a nickel cobalt aluminum precursor having multi-layered circular pores by precisely controlling the coprecipitation pH value and coprecipitation time at each stage of the three elements. The manufacturing method is simple in process, low in cost, and capable of industrial production.

[0019] 2. Compared with the conventional precursor, in the spherical secondary structure of the precursor, there is a large internal space between the primary particles. The cathode material inherits many of the morphological structure and physical property indicators of the precursor. For the cathode material manufactured in the present invention, the doped and coated elements penetrate not only the surface of the spherical secondary particles but also into the circular pores, protecting the primary particles that make up the spherical secondary particles. The electrolyte penetrates into the multi-layered circular pores of the cathode material, expanding the contact area between the cathode material and the electrolyte, shortening the diffusion path of Li + , and accelerating the absorption and release rate of lithium ions. Thereby, the battery not only has a high initial discharge specific capacity but also has a small internal resistance of the battery, improving the output performance. Also, the presence of the multi-layered circular pores buffers the volume change during charge and discharge of the cathode material, stabilizing the structure, and playing a role in improving the cycle performance.

Brief Description of the Drawings

[0020] [Figure 1] This is a cross-sectional scanning electron microscope image of the precursor from Example 1. [Figure 2] This is a cross-sectional scanning electron microscope image of the precursor from Example 2. [Figure 3] This is a cross-sectional scanning electron microscope image of the precursor of Comparative Example 1. [Figure 4] This is a cross-sectional scanning electron microscope image of the precursor of Comparative Example 2. [Figure 5] This is a comparative diagram of the rate performance of the cathode materials manufactured in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4. [Figure 6] This is a comparison chart of the cycle performance of the cathode materials produced in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4. (Table 1) This is a comparison chart of the porosity of the precursors produced in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4, as well as the discharge capacity and DCR performance of the cathode materials. [Modes for carrying out the invention]

[0021] The concept, specific structure, and resulting technical effects of this application will be clearly and completely described below with reference to examples.

[0022] (Example 1) 1. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor, comprising the following steps S1 to S5.

[0023] In S1, nickel sulfate and cobalt sulfate powders are weighed and dissolved in pure water to prepare a mixed nickel and cobalt salt solution according to a Ni:Co molar ratio of 0.875:0.09, and the molar concentration of all metal ions in the mixed nickel and cobalt salt solution is 2.0 mol / L.

[0024] In S2, weigh out the sodium metaaluminate and add it to the sodium hydroxide solution, Al 3+ An alkali aluminum solution with a molar concentration of 0.1 mol / L was prepared.

[0025] In step S3, the nickel-cobalt mixed salt solution from S1, the alkali-aluminum solution from S2, and a 12 mol / L ammonia-water complexing agent were simultaneously pumped into the reaction vessel, and the coprecipitation reaction was carried out while stirring. The coprecipitation reaction was divided into four stages, and the temperature was controlled to 55°C throughout. In the first stage, the nickel-cobalt mixed salt solution at a flow rate of 2.52 L / h, the alkali-aluminum solution at a flow rate of 1.8 L / h, and the complexing agent solution at a flow rate of 0.5 to 1.5 L / h were pumped into the reaction vessel, the pH value was controlled to 11.89 ± 0.1, and the stirring speed was set to 850 rpm, allowing the particles D50 in the reaction vessel to grow to 4 to 6 μm. In the second stage, a nickel-cobalt mixed salt solution at a flow rate of 2.45 L / h, an alkali-aluminum solution at a flow rate of 1.5 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were pumped into the reaction vessel, the pH value was controlled to 11.62 ± 0.1, and the stirring speed was set to 550 rpm, allowing the particles D50 in the reaction vessel to grow to 6-9 μm. In the third stage, a nickel-cobalt mixed salt solution at a flow rate of 2.55 L / h, an alkali-aluminum solution at a flow rate of 1.65 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were pumped into the reaction vessel, the pH value was controlled to 11.45 ± 0.1, and the stirring speed was set to 650 rpm, allowing the particles in the reaction vessel to grow to 9-13 μm. In the fourth stage, a nickel-cobalt mixed salt solution at a flow rate of 2.55 L / h, an alkali-aluminum solution at a flow rate of 1.65 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were pumped into the reaction vessel. The pH value was controlled to 11.65 ± 0.1, the stirring speed was set to 500 rpm, and the particles D50 in the reaction vessel were allowed to grow to 15 ± 1 μm before being stopped.

[0026] In S4, the overflow liquid from the reaction vessel in S3 is collected and concentrated. The material obtained from the reaction is first washed with a sodium hydroxide solution, and then washed with deionized water at 25°C. The resistivity of the washing water after washing is less than 0.02 cm / μs, and the molar concentration of the alkaline solution is 4.0 to 5.0 mol / L. The oven drying temperature is set to 105°C, and the moisture content is controlled to 0.5 wt% or less. The content of magnetic foreign matter in the precursor must be controlled to 100 ppb or less.

[0027] In this manufacturing method, the nickel-cobalt-aluminum precursor Ni has a D50 of 15.097, a porosity of 8.348, and a multilayer annular pore structure. 0.875 Co 0.09 Al 0.035 (OH)2 can be obtained.

[0028] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was ZrO2. The molar ratio of (Ni+CO+Al):Li was 1:1.03, and the mass ratio of ZrO2 to the total mass of the precursor and lithium salt was 0.3%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 720°C for 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, with a mass ratio of primary sintered substrate to water of 1:1.5 and a deionized water temperature of 25°C. It was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate was uniformly mixed with cerium oxide, which is a coating material, with a mass ratio of cerium oxide to dried substrate of 0.1%. Subsequently, it was calcined in an oxygen atmosphere furnace, with a calcination temperature of 650°C, a calcination time of 8 hours, and an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.875 Co 0.09 Al 0.035 Zr 0.003 A cathode material of O2@CeO2 was obtained.

[0029] Using an argon ion cross-section plotter, Ni obtained in S4 0.875 Co 0.09 Al 0.035 The (OH)2 nickel-cobalt-aluminum precursor was cut, and the cross-sectional morphology was observed using a field emission scanning electron microscope. The test results are shown in Figure 1.

[0030] Using ImageJ, particle porosity analysis was performed on the cross-sectional view of the precursor. The calculation of particle cross-sectional porosity is mainly based on the proportion of pores within the particle. In ImageJ, one copy of the original image is used to extract the pore area, and the copied image is used to extract the area of ​​the particle after filling the pores. The ratio of these two is the porosity of the particle cross-section. The test results are shown in Table 1.

[0031] 2. Electrical performance test All 18650 batteries were assembled and used to test the electrical performance of the positive electrode material in Example 1. The positive electrode material consisted of (96.5%), SuperP (1.2%), CNT (0.5%), and PVDF (1.8%), while graphite was used as the negative electrode, consisting of graphite (94.8%), CMC (1.7%), SBR (2%), and SuperP (1.5%). In the overall battery design, the positive / negative electrode capacity ratio was 1 / 1.2.

[0032] 1) Gram Capacity Test: The batteries were assembled into 18650 cylindrical batteries, followed by chemical conversion and capacity grading. The chemical conversion voltage was 2.75-4.2V, and the initial efficiency (initial efficiency % = 0.2C discharge capacity / initial charge capacity) and 0.2C discharge gram capacity were calculated. The results are shown in Table 1.

[0033] 2) Rate Performance Test: After chemical formation and capacity grading of assembled 18650 cylindrical batteries, the formed batteries were subjected to discharge tests at different rates within a room temperature of 25°C and a voltage range of 2.75 to 4.2V. The charge rate was 0.5C in all cases, and the discharge rates were 0.5C, 1C, 2C, and 3C, respectively. The discharge capacity retention rates for the different rates were calculated, and the results are shown in Table 1.

[0034] 3) Cycle performance test: After conventional chemical formation and capacity grading were performed on assembled 18650 cylindrical batteries, the formed batteries were charged at a rate of 0.5C and discharged at a rate of 1C at room temperature of 25°C and within a voltage range of 2.75 to 4.2V. The capacity retention rate results are shown in Figure 6.

[0035] 4) DCR Performance Test: After conventional chemical formation and capacity grading, assembled 18650 cylindrical batteries were subjected to a room temperature DCR test. The procedure for the room temperature DCR test was as follows: The chemically formed batteries were fully charged at a 1C rate at room temperature of 25°C and within a voltage range of 2.75~4.2V and left to stand. Then, they were discharged at a 1C rate to 50% SOC and 10% SOC, respectively, and left to stand. After that, a 10s pulse discharge was performed at 1C, and the voltage change before and after the pulse discharge was recorded. DCR data at 50% SOC and 10% SOC at room temperature was obtained according to the calculation formula DCR = (voltage at the end of standing - voltage after pulse discharge) / pulse current, and the results are shown in Table 1.

[0036] (Example 2) In S1, nickel sulfate and cobalt sulfate powders are weighed and dissolved in pure water to prepare a mixed nickel and cobalt salt solution according to a Ni:Co molar ratio of 0.92:0.03, and the molar concentration of all metal ions in the mixed nickel and cobalt salt solution is 2.0 mol / L.

[0037] In S2, weigh out the sodium metaaluminate and add it to the sodium hydroxide solution, Al 3+ An alkali aluminum solution with a molar concentration of 0.5 mol / L was prepared.

[0038] In step S3, the nickel-cobalt mixed salt solution from S1, the alkali-aluminum solution from S2, and a 12 mol / L ammonia-water complexing agent were simultaneously pumped into the reaction vessel, and a coprecipitation reaction was carried out while stirring. The coprecipitation reaction was divided into four stages, and the temperature was controlled to 55°C throughout. In the first stage, the nickel-cobalt mixed salt solution at a flow rate of 2.55 L / h, the alkali-aluminum solution at a flow rate of 1.85 L / h, and the complexing agent solution at a flow rate of 0.5 to 1.5 L / h were pumped into the reaction vessel, the pH value was controlled to 11.92 ± 0.1, and the stirring speed was set to 850 rpm, allowing the particles D50 in the reaction vessel to grow to 4 to 6 μm. In the second stage, a nickel-cobalt mixed salt solution at a flow rate of 2.43 L / h, an alkali-aluminum solution at a flow rate of 1.45 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were simultaneously pumped into the reaction vessel, the pH value was controlled to 11.65 ± 0.1, and the stirring speed was set to 550 rpm, allowing the particles D50 in the reaction vessel to grow to 6-9 μm. In the third stage, a nickel-cobalt mixed salt solution at a flow rate of 2.5 L / h, an alkali-aluminum solution at a flow rate of 1.65 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were simultaneously pumped into the reaction vessel, the pH value was controlled to 11.48 ± 0.1, and the stirring speed was set to 650 rpm, allowing the particles in the reaction vessel to grow to 9-13 μm. In the fourth stage, a nickel-cobalt mixed salt solution at a flow rate of 2.5 L / h, an alkali-aluminum solution at a flow rate of 1.6 L / h, and a complexing agent solution at a flow rate of 0.5-1.5 L / h were simultaneously pumped into the reaction vessel. The pH value was controlled to 11.54 ± 0.1, the stirring speed was set to 500 rpm, and the particles D50 in the reaction vessel were allowed to grow to 15 ± 1 μm before being stopped.

[0039] In S4, the overflow liquid from the reaction vessel in S3 is collected and concentrated. The material obtained from the reaction is first washed with a sodium hydroxide solution, and then washed with deionized water at 25°C. The resistivity of the wash water after washing is less than 0.02 cm / μs, and the molar concentration of the alkaline solution is 4.0 to 5.0 mol / L. The oven drying temperature is 105°C, and the moisture content is controlled to 0.5 wt% or less. The content of magnetic foreign matter in the precursor must be controlled to 100 ppb or less.

[0040] In this manufacturing method, the nickel-cobalt-aluminum precursor Ni has a D50 of 14.792, a porosity of 9.465, and a multilayer annular pore structure. 0.92 Co 0.03 Al 0.05 (OH)2 can be obtained.

[0041] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, the additive used was ZrO2, the molar ratio of (Ni+CO+Al):Li was 1:1.03, and the mass ratio of ZrO2 to the total mass of the precursor and lithium salt was 0.3%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 700°C for 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, where the mass ratio of the primary sintered substrate to water was 1:1.5, and the temperature of the deionized water was 25°C. The mixture was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate was uniformly mixed with cerium fluoride, which is a coating material, with a mass ratio of cerium fluoride to the dried substrate of 0.2%. Subsequently, it was calcined in an oxygen atmosphere furnace, with a calcination temperature of 650°C, a calcination time of 8 hours, and an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.92 Co 0.03 Al 0.05 Zr 0.003 O2@CeF4 cathode material was obtained.

[0042] Using an argon ion cross-section plotter, Ni obtained in S4 0.92 Co 0.03 Al 0.05 The (OH)2 nickel-cobalt-aluminum precursor was cut, and the cross-sectional morphology was observed using a field emission scanning electron microscope. The test results are shown in Figure 2.

[0043] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0044] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0045] (Example 3) Referring to S1-S4 in Example 1, the nickel-cobalt-aluminum precursor Ni has a D50 of 15.097, a porosity of 8.348, and a multilayer annular pore configuration. 0.875 Co 0.09 Al 0.035 (OH)2 can be obtained.

[0046] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was B2O3. The molar ratio of (Ni+CO+Al):Li was 1:1.03, and the mass ratio of B2O3 to the total mass of the precursor and lithium salt was 0.15%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 720°C for 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, where the ratio of primary sintered substrate to water was 1:1.5, and the temperature of the deionized water was 25°C. The mixture was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate was uniformly mixed with zirconia, which is the coating material, with a mass ratio of zirconia to dried substrate of 0.1%. Subsequently, it was calcined in an oxygen atmosphere furnace at a calcination temperature of 600°C for 8 hours, with an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.875 Co 0.09 Al 0.035 B 0.0015 A cathode material of O2@ZrO2 was obtained.

[0047] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0048] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0049] (Example 4) Referring to S1-S4 in Example 2, the nickel-cobalt-aluminum precursor Ni has a D50 of 14.792, a porosity of 9.465, and a multilayer annular pore configuration. 0.92 Co 0.03 Al 0.05 (OH)2 was obtained.

[0050] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was B2O3. The molar ratio of (Ni+CO+Al):Li was 1:1.03, and the mass ratio of B2O3 to the total mass of the precursor and lithium salt was 0.1%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 700°C for 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, with a mass ratio of primary sintered substrate to water of 1:1.5, and the temperature of the deionized water was 25°C. The mixture was then centrifuged and oven-dried to obtain a dried substrate. The mass ratio of boric acid to the dried substrate was 0.05%. Subsequently, it was calcined in an oxygen atmosphere furnace at a calcination temperature of 350°C for a calcination time of 5 hours, with an oxygen content of 80% to 95% in the atmosphere furnace. 1.03 Ni 0.92 Co 0.03 Al 0.05 B 0.001 O2@Li3BO3 cathode material was obtained.

[0051] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0052] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0053] (Comparative Example 1) 1. A conventional method for producing a nickel-cobalt-aluminum precursor and a cathode material sintering method comprising the following steps S1 to S5.

[0054] In S1, nickel sulfate and cobalt sulfate powders are weighed and dissolved in pure water to prepare a mixed nickel and cobalt salt solution according to a Ni:Co molar ratio of 0.875:0.09, and the molar concentration of all metal ions in the mixed nickel and cobalt salt solution is 2.0 mol / L.

[0055] In S2, weigh out the sodium metaaluminate and add it to the sodium hydroxide solution, Al 3+ An alkali aluminum solution with a molar concentration of 0.1 mol / L was prepared.

[0056] In step S3, the nickel-cobalt mixed salt solution S1, the alkali-aluminum solution S2, and a 12 mol / L aqueous ammonia complexing agent were simultaneously pumped into the reaction vessel, and a coprecipitation reaction was carried out while stirring. No step-process adjustments were made to the growth process of precursor D50. The temperature in the reaction vessel was controlled to 55°C overall, the pH value of the entire reaction was maintained at 11.2-12.2, and the stirring speed was set to 600 ± 100 rpm. When the particles D50 in the reaction vessel grew to 15 ± 1 μm, the reaction was stopped.

[0057] In S4, the overflow liquid from the reaction vessel in S3 is collected and concentrated. The material obtained from the reaction is first washed with a sodium hydroxide solution, and then washed with deionized water at 25°C. The resistivity of the wash water after washing is less than 0.02 cm / μs, and the molar concentration of the alkaline solution is 4.0 to 5.0 mol / L. The oven drying temperature is 105°C, and the moisture content is controlled to 0.5 wt% or less. The content of magnetic foreign matter in the precursor must be controlled to 100 ppb or less.

[0058] In this manufacturing method, D50 = 14.837, porosity 2.12, and conventional dense Ni 0.875 Co 0.09 Al 0.035 (OH)2 nickel-cobalt-aluminum precursor was obtained.

[0059] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was ZrO2. The molar ratio of (Ni+CO+Al):Li was 1.01-1.05:1, and the mass ratio of ZrO2 to the total mass of the precursor and lithium salt was 0.3%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 720°C for 10 hours, with an oxygen content of 90%-95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, with a mass ratio of primary sintered substrate to water of 1:1.5 and a deionized water temperature of 25°C. It was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate was uniformly mixed with cerium oxide, which is a coating material, with a mass ratio of cerium oxide to dried substrate of 0.1%. Subsequently, it was calcined in an oxygen atmosphere furnace, with a calcination temperature of 650°C, a calcination time of 8 hours, and an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.875 Co 0.09 Al 0.035 Zr 0.003 A cathode material of O2@CeO2 was obtained.

[0060] Using an argon ion cross-section plotter, Ni obtained in S4 0.875 Co 0.09 Al 0.035 The (OH)2 nickel-cobalt-aluminum precursor was cut, and the cross-sectional morphology was observed using a field emission scanning electron microscope. The test results are shown in Figure 3.

[0061] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0062] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0063] (Comparative Example 2) In S1, nickel sulfate and cobalt sulfate powders are weighed and dissolved in pure water to prepare a mixed nickel and cobalt salt solution according to a Ni:Co molar ratio of 0.92:0.03, and the molar concentration of all metal ions in the mixed nickel and cobalt salt solution is 2.0 mol / L.

[0064] In S2, weigh out the sodium metaaluminate and add it to the sodium hydroxide solution, Al 3+ An alkali aluminum solution with a molar concentration of 0.5 mol / L was prepared.

[0065] In S3, the nickel-cobalt mixed salt solution S1, the alkali-aluminum solution S2, and a 12 mol / L aqueous ammonia complexing agent were simultaneously pumped into the reaction vessel, and a coprecipitation reaction was carried out while stirring.

[0066] Without adjusting the step-by-step process during the growth of precursor D50, the temperature in the reaction vessel was controlled to a constant 55°C, the overall pH value of the reaction was maintained at 11.2-12.2, and the stirring speed was set to 600±100 rpm. The reaction was stopped when the D50 particles in the reaction vessel grew to 15±1 μm.

[0067] In S4, the overflow liquid from the reaction vessel in S3 is collected and concentrated. The material obtained from the reaction is first washed with a sodium hydroxide solution, and then washed with deionized water at 25°C. The resistivity of the wash water after washing is less than 0.02 cm / μs, and the molar concentration of the alkaline solution is 4.0 to 5.0 mol / L. The oven drying temperature is 105°C, and the moisture content is controlled to 0.5 wt% or less. The content of magnetic foreign matter in the precursor must be controlled to 100 ppb or less.

[0068] In this manufacturing method, D50 = 15.167, porosity 1.95, and conventional dense Ni 0.92 Co 0.03 Al 0.05 (OH)2 nickel-cobalt-aluminum precursor was obtained.

[0069] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was ZrO2. The molar ratio of (Ni+CO+Al):Li was 1.01-1.05:1, and the mass ratio of ZrO2 to the total mass of the precursor and lithium salt was 0.3%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 700°C for 10 hours, with an oxygen content of 90%-95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, with a mass ratio of primary sintered substrate to water of 1:1.5, and the temperature of the deionized water was 25°C. The mixture was then centrifuged and oven-dried to obtain a dried substrate. The mass ratio of cerium fluoride to the dried substrate was 0.2%. Subsequently, it was calcined in an oxygen atmosphere furnace, with a calcination temperature of 650°C, a calcination time of 8 hours, and an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.92 Co 0.03 Al 0.05 Zr 0.003 O2@CeF4 cathode material was obtained.

[0070] Using an argon ion cross-section plotter, Ni obtained in S4 0.92 Co 0.03 Al 0.05 The (OH)2 nickel-cobalt-aluminum precursor was cut, and the cross-sectional morphology was observed using a field emission scanning electron microscope. The test results are shown in Figure 4.

[0071] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0072] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0073] (Comparative Example 3) Referring to S1 to S4 in Comparative Example 1, D50 = 14.837, porosity is 2.12, and Ni has a conventional dense form. 0.875 Co 0.09 Al 0.035(OH)2 nickel-cobalt-aluminum precursor was obtained.

[0074] In step S5, the nickel-cobalt-aluminum precursor obtained in step S4, the lithium salt, and the additive were uniformly mixed. The lithium salt used in step S5 was lithium hydroxide, and the additive used was B2O3. The molar ratio of (Ni+CO+Al):Li was 1.03:1, and the mass ratio of B2O3 to the total mass of the precursor and lithium salt was 0.15%. The mixture was calcined in an oxygen atmosphere furnace at a calcination temperature of 720°C for 10 hours, with an oxygen content of 90% to 95% in the atmosphere furnace, to obtain a primary sintered substrate. The obtained primary sintered substrate was pulverized and washed with deionized water, with a mass ratio of primary sintered substrate to water of 1:1.5 and a deionized water temperature of 25°C. The mixture was then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate was uniformly mixed with zirconia, which is the coating material, with a mass ratio of zirconia to dried substrate of 0.1%. Subsequently, it was calcined in an oxygen atmosphere furnace at a calcination temperature of 600°C for 8 hours, with an oxygen content of 90% to 95% in the atmosphere furnace. 1.03 Ni 0.875 Co 0.09 Al 0.035 B 0.0015 A cathode material of O2@ZrO2 was obtained.

[0075] The method for testing the porosity of the cross-sectional view of the precursor was the same as in Example 1, and the results are shown in Table 1.

[0076] The manufacturing process for the 18650 cylindrical battery was the same as in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figure 5, and Figure 6.

[0077] (Comparative Example 4) Referring to S1-S4 in Comparative Example 2, D50 = 15.167, porosity is 3.34, and Ni has a conventional dense morphology. 0.92 Co 0.03 Al 0.05 (OH)2 nickel-cobalt-aluminum precursor was obtained.

[0078] In S5, the nickel cobalt aluminum precursor obtained in S4, lithium salt, and additive are uniformly mixed. The lithium salt used in S5 is lithium hydroxide, the additive used is B2O3, the molar ratio of (Ni + Co + Al):Li is 1.03:1, and the mass ratio of B2O3 to the total mass of the precursor and lithium salt is 0.1%. It is calcined in an oxygen atmosphere furnace, the calcination temperature is 700 °C, the calcination time is 10 h, the oxygen content in the atmosphere furnace is 90% - 95%, and a primary sintered substrate is obtained. The obtained primary sintered substrate is pulverized and washed with deionized water. However, the mass ratio of the primary sintered substrate to water is 1:1.5, the temperature of the deionized water is 25 °C, it is centrifuged and oven dried to obtain a dried substrate. The mass ratio of boric acid to the dried substrate is 0.05%. Then, it is calcined in an oxygen atmosphere furnace, the calcination temperature is 350 °C, the calcination time is 5 h, the oxygen content in the atmosphere furnace is 80% - 95%, and Li 1.03 Ni 0.92 Co 0.03 Al 0.05 B 0.001 O2@Li3BO3 cathode material was obtained.

[0079] The cross-sectional porosity test method of the precursor is the same as that in Example 1, and the results are shown in Table 1.

[0080] The manufacturing process of the 18650 cylindrical battery is the same as that in Example 1, and its electrical performance was tested under the same test conditions. The results are shown in Table 1, Figures 5 and 6.

Table 1

[0081] The experimental data is divided into two sets: Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2. As can be seen from the experimental data results, by strictly controlling the pH value, rotation speed, and solution flow rate during the coprecipitation reaction process of the precursor in stages, a precursor with multilayer annular pores can be obtained. In the comparative examples, if the reaction stages are not adjusted or adjustments are not made according to this method, a precursor of this form cannot be obtained. This form greatly affects the porosity index. Among cathode materials with the same nickel-cobalt-aluminum ratio, those with a relatively large porosity value have a higher initial discharge gram capacity. By the cathode material inheriting the internal spatial structure of the precursor, it is possible to penetrate more electrolyte and provide more lithium ion diffusion pathways, thereby accelerating the intercalation and release rates of lithium ions. Therefore, Examples 1 and 2 have a higher initial discharge ratio capacity and lower internal resistance compared to Comparative Examples 1 and 2. Furthermore, comparing the data from these two sets, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4, reveals that while doping or coating with different elements can improve the electrical performance of the cathode material to some extent, it still cannot improve the advantages inherited from the precursor structure itself.

[0082] Experimental data further shows that among cathode materials with the same nickel-cobalt-aluminum ratio, those with a relatively larger porosity value exhibit superior cycle performance. This is because the cathode inherits a porous structure between primary particles from the precursor, and after lithium-sintering the precursor, many voids remain between the primary particles. The elements coated during secondary sintering also penetrate to the surface of the primary particles, protecting the cathode material and improving side reactions that occur in the cathode material due to the electrolyte. It is known that changes in morphology have a significant impact on the cycle stability of nickel-rich NCA cathodes, and that crystal lattice shrinkage occurs in the cathode due to phase changes near the end of charging. Appropriate voids between primary particles allow internal strain due to phase changes to be uniformly distributed, reliably dissipating the strain force and thereby improving cycle characteristics.

Claims

1. A multilayer annular-pore nickel-cobalt-aluminum precursor, The chemical formula is NiMCoNA1-M-N(OH)2, with 0.8 ≤ M ≤ 0.97, 0.02 ≤ N ≤ 0.09, and 0.01 ≤ 1-M-N ≤ 0.055, where D50 is 8 μm to 20 μm, and the spherical secondary particle structure of the precursor has multilayer annular pores, and the porosity value, which is the cross-sectional average value of one or more spherical secondary particles, is 6% to 14%. The method for producing the multilayer annular-pore nickel-cobalt-aluminum precursor is as follows: Step S1 involves weighing nickel sulfate and cobalt sulfate powder and dissolving them in pure water to prepare a nickel-cobalt mixed salt solution. Step S2 involves weighing the aluminum salt and adding it to the sodium hydroxide solution to prepare an alkali aluminum solution. Step S3 is a step in which the nickel-cobalt mixed salt solution from step S1, the alkali-aluminum solution from step S2, and the complexing agent are simultaneously pumped into a reaction vessel to carry out a coprecipitation reaction stepwise, wherein in step S3, the concentration of the complexing agent is 10 mol / L to 15 mol / L. Step S4 includes the following steps to obtain a nickel-cobalt-aluminum precursor: after the reaction is complete, the material obtained from the reaction is subjected to solid-liquid separation, washing, oven drying, homogenization, sieving, and demagnetization. In step S3, the coprecipitation reaction is carried out in four stages: the first stage involves growing the nuclei from formation to a D150 value where 25% ≤ D150 < 40% of the target value; the second stage involves growing the spherical secondary particles in the reaction vessel to a D250 value where 40% ≤ D250 < 60% of the target value; the third stage involves growing the spherical secondary particles in the reaction vessel to a D350 value where 60% ≤ D350 < 90% of the target value; and the fourth stage involves immediately stopping the growth reaction once the spherical secondary particles have grown to the target value in the reaction vessel. A multilayer annular-pore nickel-cobalt-aluminum precursor characterized by the following features.

2. In step S1, the total metal ion concentration of the nickel-cobalt mixed salt solution is 1.0 mol / L to 2.0 mol / L. The multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1.

3. In step S2, the aluminum salt is sodium metaaluminate, and the Al in the alkali aluminum solution ３＋ The concentration is 0.1 mol / L to 0.5 mol / L, and the molar concentration of the sodium hydroxide solution is 5 mol / L to 10 mol / L. The multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1.

4. The complexing agent is at least one of EDTA, aqueous ammonia, ammonium carbonate, and ammonium bicarbonate. The multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1.

5. In step S3, the coprecipitation reaction is carried out in four stages. In each stage, the flow rate of the nickel-cobalt mixed salt solution is 1 to 3.5 L / h, the flow rate of the alkali-aluminum solution is 1 to 2 L / h, the flow rate of the complexing agent is 0.5 to 1.5 L / h, the pH is controlled to 10 to 12, the reaction temperature in each stage is controlled to 55 to 70°C, and the stirring speed in each stage is 500 to 1000 rpm. The multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1.

6. In step S4, the washing is specifically carried out by first washing the material obtained from the reaction with an alkaline solution, and then washing it with deionized water at 25°C to 80°C, wherein the resistivity of the washing water after washing is less than 0.02 cm / μs, the alkaline solution is at least one of sodium carbonate solution and sodium hydroxide solution, and the molar concentration of the alkaline solution is 4.0 mol / L to 5.0 mol / L. The multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1.

7. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to claim 1, Step S1 involves weighing nickel sulfate and cobalt sulfate powder and dissolving them in pure water to prepare a nickel-cobalt mixed salt solution. Step S2 involves weighing the aluminum salt and adding it to the sodium hydroxide solution to prepare an alkali aluminum solution. Step S3 is a step in which the nickel-cobalt mixed salt solution from step S1, the alkali-aluminum solution from step S2, and the complexing agent are simultaneously pumped into a reaction vessel to carry out a coprecipitation reaction stepwise, wherein in step S3, the concentration of the complexing agent is 10 mol / L to 15 mol / L. Step S4 includes the following steps to obtain a nickel-cobalt-aluminum precursor: after the reaction is complete, the material obtained from the reaction is subjected to solid-liquid separation, washing, oven drying, homogenization, sieving, and demagnetization. In step S3, the coprecipitation reaction is carried out in four stages: the first stage involves growing the nuclei from formation to a D150 value where 25% ≤ D150 < 40% of the target value; the second stage involves growing the spherical secondary particles in the reaction vessel to a D250 value where 40% ≤ D250 < 60% of the target value; the third stage involves growing the spherical secondary particles in the reaction vessel to a D350 value where 60% ≤ D350 < 90% of the target value; and the fourth stage involves immediately stopping the growth reaction once the spherical secondary particles have grown to the target value in the reaction vessel. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor, characterized by the above.

8. In step S1, the total metal ion concentration of the nickel-cobalt mixed salt solution is 1.0 mol / L to 2.0 mol / L. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to feature 7.

9. In step S2, the aluminum salt is sodium metaaluminate, and the Al in the alkali aluminum solution ３＋ The concentration is 0.1 mol / L to 0.5 mol / L, and the molar concentration of the sodium hydroxide solution is 5 mol / L to 10 mol / L. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to feature 7.

10. The complexing agent is at least one of EDTA, aqueous ammonia, ammonium carbonate, and ammonium bicarbonate. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to feature 7.

11. In step S3, the coprecipitation reaction is carried out in four stages. In each stage, the flow rate of the nickel-cobalt mixed salt solution is 1 to 3.5 L / h, the flow rate of the alkali-aluminum solution is 1 to 2 L / h, the flow rate of the complexing agent is 0.5 to 1.5 L / h, the pH is controlled to 10 to 12, the reaction temperature in each stage is controlled to 55 to 70°C, and the stirring speed in each stage is 500 to 1000 rpm. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to feature 7.

12. In step S4, the washing is specifically carried out by first washing the material obtained from the reaction with an alkaline solution, and then washing it with deionized water at 25°C to 80°C, wherein the resistivity of the washing water after washing is less than 0.02 cm / μs, the alkaline solution is at least one of sodium carbonate solution and sodium hydroxide solution, and the molar concentration of the alkaline solution is 4.0 mol / L to 5.0 mol / L. A method for producing a multilayer annular-pore nickel-cobalt-aluminum precursor according to feature 7.

13. A nickel-cobalt-aluminum precursor is obtained using the manufacturing method of claim 7, and then the obtained precursor is uniformly mixed with a lithium source and additives, and then primary sintering, crushing, grinding, washing with water and oven drying, coating, secondary sintering and sieving are performed to obtain a positive electrode material. A method for manufacturing a positive electrode material for a lithium-ion battery, characterized by the following features.

14. The lithium source is at least one of lithium hydroxide, lithium nitrate, and lithium chloride; the additive is one or more of the elements Zr, Sr, Ti, W, Mg, Y, La, B, and F; the coating agent used during coating is one or more of element D-containing oxides and element D-containing lithium compounds, element D is one or more of Co, Li, B, W, Ti, Ce, and Zr; the molar ratio of Ni + CO + Al:Li is 1:1.01 to 1.05; and the mass ratio of the additive used to the total mass of the precursor and lithium salt is 0.1% to The material content is 2%, and during primary sintering, it is calcined in an oxygen atmosphere furnace at a calcination temperature of 650°C to 800°C for a calcination time of 10 to 15 hours, with an oxygen content of 85% to 95% in the atmosphere furnace to obtain a primary sintered substrate. The obtained primary sintered substrate is pulverized and washed with deionized water, where the mass ratio of primary sintered substrate to water is 1:1 to 3, and the temperature of the deionized water is 20°C to 30°C. It is then centrifuged and oven-dried to obtain a dried substrate. The obtained dried substrate and the coating agent are uniformly mixed, where the mass ratio of coating agent to dried substrate is 0.01% to 5%. Subsequently, secondary sintering is performed, followed by calcination in an oxygen atmosphere furnace at a calcination temperature of 500°C to 700°C, a calcination time of 6 to 10 hours, and an oxygen content of 90% to 95% in the atmosphere furnace to obtain the positive electrode material. A method for producing a positive electrode material for a lithium-ion battery according to feature 13.

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