Preparation method of radial order type ultra-high nickel positive electrode material precursor

Abstract

The application discloses a method for preparing a radial ordered ultra-high nickel positive electrode material precursor, which comprises the following steps: applying a constant magnetic field parallel to the stirring shaft to the reaction system in the growth reaction stage of the coprecipitation reaction, utilizing the weak magnetism of the ultra-high nickel precursor crystal nucleus to induce the directional arrangement of the primary crystal grains along the magnetic field direction, and cooperating with the axial flow field in the reaction kettle to orderly assemble the directional arrangement of the primary crystal grains to form the spherical secondary particles with the radial ordered structure. Through the magnetic field regulation, the high-precision orientation of the primary particle of the precursor along the radial direction is realized, the phase change stress of the ultra-high nickel positive electrode material in the charging and discharging process can be significantly relieved after the obtained precursor is subjected to the lithiumization sintering, the micro-cracks are inhibited, the cycle stability is greatly improved, the method is simple and controllable, and the industrial production is easy, so the method has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery cathode material technology, specifically relating to a method for preparing a radially ordered ultra-high nickel cathode material precursor. Background Technology

[0002] With the rapid development of the new energy vehicle industry, higher demands are being placed on the energy density of lithium-ion batteries. Ultra-high nickel ternary cathode materials, due to their high energy density and other advantages, have become one of the core materials for next-generation power batteries. However, ultra-high nickel materials face serious structural degradation problems during charge and discharge: the H2-H3 phase transition causes anisotropic contraction / expansion of the lattice, leading to stress accumulation within secondary particles, which in turn triggers the generation and propagation of intergranular microcracks, accelerating capacity decay and posing safety hazards.

[0003] Studies have shown that by controlling the primary particle arrangement of the precursor to construct a radially ordered structure (i.e., primary particles arranged in a spoke-like pattern along the radius of secondary particles), phase transformation stress can be effectively discretized, microcrack initiation suppressed, and the cycle stability of ultra-high nickel materials significantly improved. Currently, methods for preparing radially ordered precursor structures mainly rely on chemical control. However, these chemical control methods are extremely sensitive to reaction conditions, have narrow process windows, struggle to guarantee batch stability, and are difficult to achieve high-precision grain orientation. For example, invention patent CN119706978A discloses a uniformly radial cathode material precursor and its preparation method; however, the oxygen content in the reactor needs to be continuously adjusted during precursor preparation, which complicates the operation. Furthermore, the introduction of oxygen can cause Mn... 2+ Oxidation affects the purity of the layered phase in the subsequent sintering material, thereby reducing the electrochemical performance of the material. Patent publication number CN117228744A discloses a radial microstructure lithium-ion battery nickel-based cathode material and its preparation method; however, this method uses urea as a raw material, significantly increasing manufacturing costs and making it unsuitable for large-scale production. Patent publication number CN118978192A discloses a radial cathode precursor, its preparation method, and its application. This patent uses carbonate as the first precipitant, which easily causes a large amount of CO2 release during subsequent sintering of the precursor. Furthermore, gas release may lead to porosity defects within the material, affecting the tap density and electrochemical performance of the cathode material.

[0004] Therefore, a method for preparing radially ordered ultra-high nickel cathode material precursors is needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing a radially ordered ultra-high nickel cathode material precursor. This method proposes introducing a magnetic field into the co-precipitation preparation process of the ultra-high nickel precursor. By utilizing the orientation effect of the magnetic field on weakly magnetic nuclei, the physical orientation of primary particles is achieved, constructing a radially ordered structure. This provides a new method for preparing high-performance ultra-high nickel cathode material precursors. The resulting cathode material can significantly improve the cycle performance of the battery and increase the cycle life of the ultra-high nickel cathode material, thus solving the technical problem that existing chemical control methods are unable to accurately control the directional arrangement of primary particles.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a radially ordered ultra-high nickel cathode material precursor, characterized in that the chemical formula of the precursor is Ni x Co y Mn 1-x-y (OH)₂, and satisfying 0.88≤x≤0.96, 0.01≤y≤0.11, the precursor is composed of spherical secondary particles formed by the agglomeration of primary grains, the cross-sectional morphology of the secondary particles being an ordered radial distribution of elongated primary particles, and the preparation method of the precursor includes the following steps: Step 1: Prepare a mixed salt solution from nickel, cobalt, and manganese sources; prepare a NaOH solution as a precipitant; and prepare an ammonia solution as a complexing agent. Step 2: Add the bottom liquid to the reaction vessel, and then simultaneously add the mixed salt solution, precipitant and complexing agent prepared in Step 1 to the bottom liquid to carry out the nucleation reaction. Step 3: After the nucleation reaction in Step 2 is completed, continue to add the mixed salt solution prepared in Step 1, reduce the dropping rate of the precipitant and complexing agent, adjust the pH, ammonia concentration and stirring rate of the reaction system, and apply a magnetic field to the reactor to carry out the growth reaction; Step 4: After the growth reaction in Step 3 reaches the target particle size, the feed is stopped. Then, the material is aged, washed, and dried in sequence to obtain a radially ordered ultra-high nickel cathode material precursor.

[0007] The principle of this invention is as follows: In the initial stage of the coprecipitation reaction, the generated ultra-high nickel hydroxide crystal nuclei have a certain degree of weak magnetism. Under the action of an external magnetic field, the crystal nuclei are magnetized and generate magnetic moments, and rotate and align along the direction of the magnetic field. By rationally designing the direction of the magnetic field, the long axis direction of the crystal nuclei tends to be consistent. At the same time, by controlling the flow field in the reactor through the stirring paddle, these oriented crystal nuclei can be transported and assembled into the surface of the growing secondary particles in an orderly manner, avoiding disordered accumulation. Through the synergistic effect of the magnetic field and the flow field, a microstructure in which the primary particles are radially arranged along the radius direction of the secondary particles is finally obtained.

[0008] In this invention, the chemical formula of the controlled precursor is Ni.x Co y Mn 1-x-y (OH)2, and satisfying 0.88≤x≤0.96 and 0.01≤y≤0.11, makes it an ultra-high nickel material among ternary materials. Compared with ordinary ternary materials, ultra-high nickel materials have a higher energy density.

[0009] This invention involves adding a mixed salt solution, a precipitant, and a complexing agent dropwise to a base solution to induce a nucleation reaction, allowing the precursor to nucleate first. After the nucleation reaction is complete, the mixed salt solution prepared in step one is continuously added dropwise while reducing the dropping rate of the precipitant and complexing agent. The pH, ammonia concentration, and stirring rate of the reaction system are adjusted, and a magnetic field is applied to the reactor to induce a growth reaction. The morphology and tap density of the precursor are controlled, achieving nucleation before growth. By aging, the remaining mixed salt in the system is allowed to fully react, thus obtaining a radially ordered ultra-high nickel cathode material precursor.

[0010] The above-mentioned method for preparing a radially ordered ultra-high nickel cathode material precursor is characterized in that the concentration of metal ions in the mixed salt solution in step one is 1.5 mol / L to 2.5 mol / L, the nickel source, cobalt source and manganese source are sulfate, nitrate or chloride, the concentration of the NaOH solution is 3 mol / L to 5 mol / L, and the concentration of the ammonia solution is 4 mol / L to 6 mol / L.

[0011] The method for preparing a radially ordered ultra-high nickel cathode material precursor described above is characterized in that, in step two, the base solution is deionized water, and NaOH solution is added to adjust the pH value to 10-11, and the volume of the base solution accounts for 30%-40% of the volume of the reaction vessel. This invention controls the pH value of the base solution to be similar to the reaction system and controls the volume, providing an excellent liquid reaction environment.

[0012] The above-mentioned method for preparing a radially ordered ultra-high nickel cathode material precursor is characterized in that, in step two, the nucleation reaction is controlled at a reaction temperature of 50℃~80℃, a pH value of 11~12.5, a stirring speed of 400rpm~600rpm, an ammonia concentration of 5g / L~6g / L, and nitrogen gas is continuously introduced as a protective gas. The particle size D50 of the nucleated particles obtained by the nucleation reaction is 2μm~4μm. This invention ensures the effectiveness of nucleation by controlling the parameters of the nucleation reaction, preventing excessive nucleation due to excessively high pH and severe agglomeration and failure to nucleate due to excessively low pH. By controlling the particle size of the nucleated particles, the size of the crystal nuclei is controlled, facilitating the subsequent growth of the precursor.

[0013] The method for preparing a radially ordered ultra-high nickel cathode material precursor described above is characterized in that, in step three, the pH value of the system is adjusted and maintained at 10.5~11.5, the ammonia concentration at 4g / L~5g / L, the stirring speed at 200rpm~400rpm, and the reaction temperature is kept constant, while nitrogen gas is continuously introduced as a protective gas. This invention ensures the effectiveness of precursor growth by controlling the parameters of the growth reaction.

[0014] The method for preparing a radially ordered ultra-high nickel cathode material precursor described above is characterized in that the magnetic field introduced during the growth reaction in step three is a constant magnetic field parallel to the stirring axis of the reactor, with a magnetic field strength of 0.5T~1.0T. This invention, by controlling the direction and magnitude of the magnetic field, facilitates the directional arrangement of primary particles, providing a novel controllable dimension for the construction of radially ordered structures. Compared with existing chemical control methods, this method offers higher controllability and repeatability.

[0015] The method for preparing a radially ordered ultra-high nickel cathode material precursor described above is characterized in that, in step three, the target particle size in the growth reaction is a particle size D50 of 10 μm to 15 μm. By controlling the target particle size in the growth reaction, i.e., the particle size of the radially ordered ultra-high nickel cathode material precursor, this invention helps to improve the tap density of the precursor and the energy density of the battery, thereby enhancing the performance of the prepared cathode material.

[0016] Compared with the prior art, the present invention has the following advantages: 1. This invention introduces a magnetic field into the preparation process of ultra-high nickel precursors. By utilizing the physical orientation effect of the magnetic field on the paramagnetic crystal nuclei, the directional arrangement of primary particles is achieved, providing a new dimension of control for the construction of radially ordered structures. Compared with existing chemical control methods, this method has higher controllability and repeatability.

[0017] 2. The present invention adopts a synergistic design of magnetic field and flow field, which not only ensures the effective orientation of crystal nuclei, but also realizes the orderly assembly of oriented crystal nuclei, so as to obtain radially ordered precursors with higher orientation degree and more uniform structure.

[0018] 3. The preparation method of the present invention is simple and easy to industrialize. It only requires the addition of a magnetic field generating device to the existing coprecipitation equipment. The process parameters are easy to quantify and control, which facilitates large-scale production and application.

[0019] 4. The cathode material obtained by lithiation sintering the precursor prepared in this invention has a radially ordered structure, which can effectively buffer the phase transformation stress during the charging and discharging process, suppress the generation of microcracks, and significantly improve cycle stability.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 The image shows the XRD pattern of the precursor prepared in Example 1 of this invention.

[0022] Figure 2 This is a SEM image of the surface of the precursor prepared in Example 1 of the present invention.

[0023] Figure 3 This is a SEM image of the cross-section of the precursor prepared in Example 1 of the present invention.

[0024] Figure 4 The image shows a cross-section of an ultra-high nickel cathode material prepared using the precursor prepared in Example 1 of this invention.

[0025] Figure 5 SEM image of the precursor cross-section prepared for Comparative Example 1.

[0026] Figure 6 The cycling performance curves of the ultra-high nickel cathode materials obtained by sintering the precursors prepared in Example 1 and Comparative Example 1 of this invention at a high voltage of 4.5V are shown. Detailed Implementation

[0027] Example 1 This embodiment includes the following steps: Step 1: Weigh out NiSO4·6H2O, CoSO4·7H2O and MnSO4·H2O according to the molar ratio of Ni:Co:Mn of 90:5:5, dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 2 mol / L, weigh out NaOH, dissolve it in deionized water to prepare a NaOH solution with a concentration of 4 mol / L as a precipitant, and take concentrated ammonia water and dilute it to a concentration of 5 mol / L as a complexing agent. Step 2: Add 30% of the reactor volume of deionized water (pH adjusted to 10.5 with NaOH solution) as the base solution to the reactor, heat to 60°C, turn on the stirring device at 550 rpm, and continuously introduce nitrogen gas as a protective gas. Add the mixed salt solution, precipitant, and complexing agent prepared in Step 1 to the reactor dropwise at a constant flow rate. Control the reaction temperature at 60°C, the pH value at 12.2, and the ammonia concentration at 6 g / L to start the nucleation reaction. When the particle size D50 of the nucleated particles is 3 μm, the nucleation reaction ends and the growth reaction stage begins. Step 3: After the nucleation reaction in Step 2 is completed, turn on the electromagnetic field around the reactor and apply a constant magnetic field parallel to the direction of the stirring axis of the reactor with a strength of 0.6T. Reduce the stirring speed to 300 rpm, adjust and maintain the pH of the reaction system at 10.8, the ammonia concentration at 4.5 g / L, maintain the reaction temperature, and continuously introduce nitrogen gas as a protective gas to carry out the growth reaction. Step 4: Under the influence of a magnetic field, when the growth reaction in Step 3 reaches a particle size D50 of 10 μm, the feeding is stopped, and stirring continues for 2 hours. After the reaction is complete, the mixture is aged, and the resulting slurry is filtered, repeatedly washed with deionized water, and dried to obtain a Ni-containing product. 0.9 Co 0.05 Mn 0.05 (OH)2 radially ordered ultra-high nickel cathode material precursor.

[0028] In this embodiment, the nickel source can also be replaced with nickel nitrate or nickel chloride, the cobalt source can also be replaced with cobalt nitrate or cobalt chloride, and the manganese source can also be replaced with manganese nitrate or manganese chloride.

[0029] The precursor prepared in Example 1 was subjected to XRD testing, and the results are as follows: Figure 1 As shown, from Figure 1 It can be seen that the diffraction peaks of the precursor are highly consistent with the standard diffraction peaks of Ni(OH)2 (PDF#14-0117), indicating that the prepared precursor has a complete layered structure.

[0030] The surface morphology of the precursor prepared in Example 1 was observed, and the results are as follows: Figure 2 As shown, from Figure 2 It can be seen that the precursor secondary particles are spherical, and the surface is composed of slender needle-like or plate-like primary particles that are tightly packed together. The particle surface is smooth and has good sphericity.

[0031] The cross-sectional morphology of the precursor prepared in Example 1 was observed, and the results are as follows: Figure 3 As shown, from Figure 3 It can be seen that the secondary particles have obvious internal stratification. The inner layer is a tightly packed sphere, while the outer layer contains elongated primary particles that are arranged radially in an orderly manner along the radius of the secondary particles, forming a typical spoke-like structure. The radial arrangement is tight and orderly with no obvious pores.

[0032] The precursor prepared in Example 1 was mixed with LiOH·H2O at a molar ratio of 1:1.05 and then sintered at high temperature to obtain an ultra-high nickel cathode material, the cross-sectional morphology of which is shown in the figure. Figure 4 As shown, from Figure 4 It can be seen that the radially ordered structure was well maintained after high-temperature sintering. The primary particles were still arranged in the radial direction, and the particles were tightly bonded together without obvious microcracks, indicating that the structure has good thermal stability.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that no magnetic field is applied.

[0034] The cross-sectional morphology of the precursor prepared in Comparative Example 1 was observed, and the results are as follows: Figure 5 As shown, from Figure 5 It can be seen that the precursor prepared under non-magnetic field conditions has primary particles arranged randomly and disorderedly, without obvious radial orientation characteristics.

[0035] The precursors prepared in Example 1 and Comparative Example 1 were mixed with LiOH·H2O at a molar ratio of 1:1.05 and then sintered at high temperature to obtain ultra-high nickel cathode materials. These ultra-high nickel cathode materials were then mixed with conductive carbon black and polyvinylidene fluoride at a mass ratio of 8:1:1. After adjusting the viscosity with N-methylpyrrolidone, the mixtures were uniformly coated onto aluminum foil and dried in a vacuum oven at 120°C for 12 hours. The resulting products were then cut into small circular pieces with a diameter of 12 mm to serve as cathode sheets, with an active material loading of approximately 1.5 mg / cm³. 2 ; The electrochemical performance of the ultra-high nickel cathode material was tested using a traditional coin cell two-electrode system. The prepared cathode sheet was used as the cathode, lithium metal was used as the anode, and the electrolyte was a mixed solution of 1M LiPF6 dissolved in ethylene carbonate / dimethyl carbonate (volume ratio 1:1). The coin cells were assembled in an argon glove box, and the charge-discharge test was carried out on the Xinwei Battery Test System. The voltage range was 2.8V~4.5V, and the test temperature was 30℃. Figure 6 Cyclic performance curves of ultra-high nickel cathode materials obtained by sintering the precursors prepared in Example 1 and Comparative Example 1 at a current density of 1C (1C = 200 mA / g) and a high voltage of 4.5V are shown below. Figure 6 As can be seen, the ultra-high nickel cathode material prepared in Example 1 has an initial discharge capacity of 221.06 mAh / g and a capacity retention rate of 79.4% after 200 cycles, while the ultra-high nickel cathode material prepared in Comparative Example 1 has an initial discharge capacity of 221.27 mAh / g and a capacity retention rate of only 69.4% after 200 cycles. This shows that the radially ordered structure obtained by magnetic field control in this invention significantly improves the cycle stability of the ultra-high nickel cathode material, maintaining a good capacity retention rate even at a high voltage of 4.5V. This is mainly attributed to the fact that the radially ordered structure can effectively discretize phase transformation stress, suppress the generation and propagation of microcracks, and thus significantly extend the cycle life of the material.

[0036] Example 2 This embodiment includes the following steps: Step 1: Weigh out NiSO4·6H2O, CoSO4·7H2O and MnSO4·H2O according to the molar ratio of Ni:Co:Mn of 88:11:1, dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 2.5 mol / L, weigh out NaOH, dissolve it in deionized water to prepare a NaOH solution with a concentration of 5 mol / L as a precipitant, and take concentrated ammonia water and dilute it to a concentration of 6 mol / L as a complexing agent. Step 2: Add 40% of the reactor volume of deionized water (pH adjusted to 10 with NaOH solution) as the base solution to the reactor, heat to 80°C, turn on the stirring device at 400 rpm, and continuously introduce nitrogen gas as a protective gas. Add the mixed salt solution, precipitant, and complexing agent prepared in Step 1 dropwise to the reactor at a constant flow rate. Control the reaction temperature at 80°C, the pH value at 11, and the ammonia concentration at 5 g / L to start the nucleation reaction. When the particle size D50 of the nucleated particles is 4 μm, the nucleation reaction ends and the growth reaction stage begins. Step 3: After the nucleation reaction in Step 2 is completed, turn on the electromagnetic field around the reactor and apply a constant magnetic field parallel to the direction of the stirring axis of the reactor with a strength of 0.5T. Reduce the stirring speed to 200 rpm, adjust and maintain the pH of the reaction system at 10.5, the ammonia concentration at 4 g / L, maintain the reaction temperature, and continuously introduce nitrogen gas as a protective gas to carry out the growth reaction. Step 4: Under the influence of a magnetic field, when the growth reaction in Step 3 reaches a particle size D50 of 15 μm, the feeding is stopped, and stirring continues for 2 hours. After the reaction is complete, the mixture is aged, and the resulting slurry is filtered, repeatedly washed with deionized water, and dried to obtain a Ni-containing product. 0.88 Co 0.11 Mn 0.01 (OH)2 radially ordered ultra-high nickel cathode material precursor.

[0037] In this embodiment, the nickel source can also be replaced with nickel nitrate or nickel chloride, the cobalt source can also be replaced with cobalt nitrate or cobalt chloride, and the manganese source can also be replaced with manganese nitrate or manganese chloride.

[0038] Testing revealed that the precursor prepared in this embodiment possesses a complete layered structure. The secondary particles of the precursor are spherical, with their surfaces composed of tightly packed, elongated needle-like or plate-like primary particles. The particle surfaces are smooth, exhibiting good sphericity. The secondary particles exhibit distinct internal layering, with the inner layer displaying tightly packed spherical structures. In the outer layer, the primary particles are elongated and radially ordered along the radial direction of the secondary particles, forming a typical spoke-like structure. This radial arrangement is tight and orderly, with no obvious pores. The radially ordered structure in the cathode material obtained after lithiation sintering is well maintained after high-temperature sintering, with the primary particles still arranged radially and tightly bonded to each other without obvious microcracks, indicating that the structure has good thermal stability. The cycle life of the ultra-high nickel cathode material prepared from the precursor is significantly extended.

[0039] Example 3 This embodiment includes the following steps: Step 1: Weigh out NiSO4·6H2O, CoSO4·7H2O and MnSO4·H2O according to the molar ratio of Ni:Co:Mn of 96:1:3, dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.5 mol / L, weigh out NaOH, dissolve it in deionized water to prepare a NaOH solution with a concentration of 3 mol / L as a precipitant, and take concentrated ammonia water and dilute it to a concentration of 4 mol / L as a complexing agent. Step 2: Add 35% of the reactor volume of deionized water (pH adjusted to 11 with NaOH solution) as the base solution to the reactor, heat to 50°C, turn on the stirring device at 600 rpm, and continuously introduce nitrogen gas as a protective gas. Add the mixed salt solution, precipitant, and complexing agent prepared in Step 1 dropwise to the reactor at a constant flow rate. Control the reaction temperature at 50°C, the pH value at 12.5, and the ammonia concentration at 6 g / L to start the nucleation reaction. When the particle size D50 of the nucleated particles is 4 μm, the nucleation reaction ends and the growth reaction stage begins. Step 3: After the nucleation reaction in Step 2 is completed, turn on the electromagnetic field around the reactor and apply a constant magnetic field parallel to the direction of the stirring axis of the reactor with a strength of 1.0T. Reduce the stirring speed to 400 rpm, adjust and maintain the pH of the reaction system at 11.5, the ammonia concentration at 5 g / L, maintain the reaction temperature, and continuously introduce nitrogen gas as a protective gas to carry out the growth reaction. Step 4: Under the influence of a magnetic field, when the growth reaction in Step 3 reaches a particle size D50 of 15 μm, the feeding is stopped, and stirring continues for 2 hours. After the reaction is complete, the mixture is aged, and the resulting slurry is filtered, repeatedly washed with deionized water, and dried to obtain a Ni-containing product. 0.96 Co 0.01 Mn 0.03 (OH)2 radially ordered ultra-high nickel cathode material precursor.

[0040] In this embodiment, the nickel source can also be replaced with nickel nitrate or nickel chloride, the cobalt source can also be replaced with cobalt nitrate or cobalt chloride, and the manganese source can also be replaced with manganese nitrate or manganese chloride.

[0041] Testing revealed that the precursor prepared in this embodiment possesses a complete layered structure. The secondary particles of the precursor are spherical, with their surfaces composed of tightly packed, elongated needle-like or plate-like primary particles. The particle surfaces are smooth, exhibiting good sphericity. The secondary particles exhibit distinct internal layering, with the inner layer displaying tightly packed spherical structures. In the outer layer, the primary particles are elongated and radially ordered along the radial direction of the secondary particles, forming a typical spoke-like structure. This radial arrangement is tight and orderly, with no obvious pores. The radially ordered structure in the cathode material obtained after lithiation sintering is well maintained after high-temperature sintering, with the primary particles still arranged radially and tightly bonded to each other without obvious microcracks, indicating that the structure has good thermal stability. The cycle life of the ultra-high nickel cathode material prepared from the precursor is significantly extended.

[0042] Example 4 This embodiment includes the following steps: Step 1: Weigh out NiSO4·6H2O, CoSO4·7H2O and MnSO4·H2O according to the molar ratio of Ni:Co:Mn of 92:4:4, dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 2 mol / L, weigh out NaOH, dissolve it in deionized water to prepare a NaOH solution with a concentration of 4 mol / L as a precipitant, and take concentrated ammonia water and dilute it to a concentration of 5.5 mol / L as a complexing agent. Step 2: Add 30% of the reactor volume of deionized water (pH adjusted to 10.5 with NaOH solution) as the base solution to the reactor, heat to 70°C, turn on the stirring device at 600 rpm, and continuously introduce nitrogen gas as a protective gas. Add the mixed salt solution, precipitant, and complexing agent prepared in Step 1 dropwise to the reactor at a constant flow rate. Control the reaction temperature at 70°C, the pH value at 12.4, and the ammonia concentration at 5.5 g / L to start the nucleation reaction. When the particle size D50 of the nucleated particles is 3 μm, the nucleation reaction ends and the growth reaction stage begins. Step 3: After the nucleation reaction in Step 2 is completed, turn on the electromagnetic field around the reactor and apply a constant magnetic field parallel to the direction of the stirring axis of the reactor with a magnetic field strength of 0.8T. Reduce the stirring speed to 400 rpm, adjust and maintain the pH value of the reaction system to 11, the ammonia concentration to 4.5 g / L, maintain the reaction temperature, and continuously introduce nitrogen gas as a protective gas to carry out the growth reaction. Step 4: Under the influence of a magnetic field, when the growth reaction in Step 3 reaches a particle size D50 of 10 μm, the feeding is stopped, and stirring continues for 2 hours. After the reaction is complete, the mixture is aged, and the resulting slurry is filtered, repeatedly washed with deionized water, and dried to obtain a Ni-containing product. 0.92 Co 0.04 Mn 0.04 (OH)2 radially ordered ultra-high nickel cathode material precursor.

[0043] In this embodiment, the nickel source can also be replaced with nickel nitrate or nickel chloride, the cobalt source can also be replaced with cobalt nitrate or cobalt chloride, and the manganese source can also be replaced with manganese nitrate or manganese chloride.

[0044] Testing revealed that the precursor prepared in this embodiment possesses a complete layered structure. The secondary particles of the precursor are spherical, with their surfaces composed of tightly packed, elongated needle-like or plate-like primary particles. The particle surfaces are smooth, exhibiting good sphericity. The secondary particles exhibit distinct internal layering, with the inner layer displaying tightly packed spherical structures. In the outer layer, the primary particles are elongated and radially ordered along the radial direction of the secondary particles, forming a typical spoke-like structure. This radial arrangement is tight and orderly, with no obvious pores. The radially ordered structure in the cathode material obtained after lithiation sintering is well maintained after high-temperature sintering, with the primary particles still arranged radially and tightly bonded to each other without obvious microcracks, indicating that the structure has good thermal stability. The cycle life of the ultra-high nickel cathode material prepared from the precursor is significantly extended.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a radially ordered ultra-high nickel cathode material precursor, characterized in that, The precursor has the chemical formula Ni x Co y Mn 1-x-y (OH)₂, and satisfying 0.88≤x≤0.96, 0.01≤y≤0.11, the precursor is composed of spherical secondary particles formed by the agglomeration of primary grains, the cross-sectional morphology of the secondary particles being an ordered radial distribution of elongated primary particles, and the preparation method of the precursor includes the following steps: Step 1: Prepare a mixed salt solution from nickel, cobalt, and manganese sources; prepare a NaOH solution as a precipitant; and prepare an ammonia solution as a complexing agent. Step 2: Add the bottom liquid to the reaction vessel, and then simultaneously add the mixed salt solution, precipitant and complexing agent prepared in Step 1 to the bottom liquid to carry out the nucleation reaction. Step 3: After the nucleation reaction in Step 2 is completed, continue to add the mixed salt solution prepared in Step 1, reduce the dropping rate of the precipitant and complexing agent, adjust the pH, ammonia concentration and stirring rate of the reaction system, and apply a magnetic field to the reactor to carry out the growth reaction; Step 4: After the growth reaction in Step 3 reaches the target particle size, the feed is stopped. Then, the material is aged, washed, and dried in sequence to obtain a radially ordered ultra-high nickel cathode material precursor.

2. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, In step one, the concentration of metal ions in the mixed salt solution is 1.5 mol / L to 2.5 mol / L, the nickel source, cobalt source, and manganese source are sulfates, nitrates, or chlorides, the concentration of the NaOH solution is 3 mol / L to 5 mol / L, and the concentration of the ammonia solution is 4 mol / L to 6 mol / L.

3. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, The bottom liquid in step two is deionized water, and NaOH solution is added to adjust the pH value to 10-11. The volume of the bottom liquid accounts for 30%-40% of the volume of the reactor.

4. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, In step two, the nucleation reaction is controlled at a temperature of 50℃~80℃, a pH value of 11~12.5, an ammonia concentration of 5g / L~6g / L, a stirring speed of 400rpm~600rpm, and nitrogen gas is continuously introduced as a protective gas. The nucleation reaction ends when the particle size D50 of the nucleated particles obtained is 2μm~4μm.

5. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, In step three, the pH of the reaction system is adjusted to 10.5~11.5, the ammonia concentration is 4g / L~5g / L, the stirring speed is 200rpm~400rpm, the reaction temperature is kept constant, and nitrogen gas is continuously introduced as a protective gas.

6. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, The magnetic field applied in the growth reaction described in step three is a constant magnetic field with a direction parallel to the stirring shaft of the reactor, and the magnetic field strength is 0.5T~1.0T.

7. The method for preparing a radially ordered ultra-high nickel cathode material precursor according to claim 1, characterized in that, The target particle size in step three is a particle size D50 of 10μm to 15μm.

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