Large-particle positive electrode material precursor, positive electrode material and application thereof

Abstract

The invention discloses a large-particle positive electrode material precursor, a positive electrode material and application of the large-particle positive electrode material precursor, the large-particle positive electrode material precursor is secondary particles which are formed by stacking primary crystal grains and have loose pores, the crystal grains in the large-particle positive electrode material precursor are arranged in a radial shape, the sizes of the crystal grains are gradually increased from inside to outside, and the particle size of the large-particle positive electrode material precursor is 6-15 microns. By regulating and controlling the morphology structure of the large-particle positive electrode material precursor, radial ordered arrangement of internal crystal grains is realized, and a microstructure with the crystal grain size gradually increased from inside to outside in a gradient manner is constructed, so that the structural stability of the precursor material is remarkably enhanced. The large-particle positive electrode material precursor presents a loose secondary particle form with high porosity, has large particle size and excellent comprehensive performance, and effectively solves the common particle cracking problem of high-nickel and ultrahigh-nickel positive electrode material precursors in the synthesis process and in the subsequent calcination preparation of the positive electrode material; therefore, the process stability and the electrochemical performance of the material are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a large-particle cathode material precursor, cathode material, and their applications. Background Technology

[0002] Advances in power battery technology are a key driver of the electric vehicle industry's development, with the optimization of cathode material performance being particularly crucial. In recent years, high-nickel and ultra-high-nickel cathode materials (typically referring to layered oxides with Ni ≥ 80 mol% such as NCM811 and NCA, and 9-series materials with 90 mol% nickel content) have become a research hotspot due to their high energy density and cost advantages. These materials increase reversible specific capacity by increasing nickel content, thereby significantly increasing battery energy density and effectively alleviating range anxiety in electric vehicles. Simultaneously, by partially replacing expensive and supply-constrained cobalt with nickel, battery manufacturing costs can be further reduced, meeting the economic needs of industry development.

[0003] However, the development of high-nickel materials faces numerous technical bottlenecks. With increasing nickel content, the stability of the material's crystal structure significantly decreases, making it prone to harmful phase transitions during long-term charge-discharge cycles. These transitions include the transformation of layered structures into electrochemically inert rock-salt phases, accompanied by lattice distortion, ultimately leading to rapid capacity decay. For traditional polycrystalline high-nickel materials, the secondary particle structure formed by the agglomeration of numerous primary particles generates intergranular cracks during cycling due to anisotropic volume changes. These cracks not only disrupt the structural integrity of the particles but also expose new active surfaces, exacerbating side reactions with the electrolyte. Furthermore, high-nickel materials typically have high alkalinity, easily forming insulating residual lithium compounds (such as Li₂CO₃ and LiOH). This not only consumes the active lithium source and increases interfacial impedance but also catalyzes electrolyte decomposition reactions, severely impacting battery cycle life and safety performance. It is noteworthy that the final performance of the cathode material largely depends on the structural characteristics and physicochemical properties of its precursor. Therefore, structural optimization and performance improvement of high-nickel / ultra-high-nickel precursor materials are crucial for solving the aforementioned problems.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a large-particle cathode material precursor, cathode material, and their applications to improve the aforementioned technical problems.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a large-particle cathode material precursor, wherein the large-particle cathode material precursor is a porous secondary particle formed by primary grain stacking, wherein the internal grains are arranged radially and the grain size gradually increases from the inside to the outside, and the particle size of the large-particle cathode material precursor is 6μm~15μm.

[0007] In an optional embodiment, the chemical structural formula of the large-particle cathode material precursor is Ni. x Co y Mn （1-x-y） M(OH)2, where 0.8≤x<1.0, 0<y<0.2, and M is a doping element, including Zr, Al, W, Ca, and Mg.

[0008] In an optional embodiment, the large-particle cathode material precursor includes a core doped with Zr and Al and a shell doped with W, Ca and Mg. The doping amount of Zr and Al in the core is 500~5000ppm, and the doping ratio of Zr to Al is (1~5):(1~5). The doping amount of W, Ca and Mg in the shell is 500~5000ppm, and the doping ratio of W, Ca and Mg is (1~5):(1~5):(1~5).

[0009] Secondly, the present invention provides a method for preparing a large-particle cathode material precursor as described in any of the foregoing embodiments, comprising: continuously introducing a nickel-cobalt-manganese mixed salt solution, a precipitant, a complexing agent, a zirconium salt solution, and an aluminum salt solution into a base solution containing a complexing agent and a precipitant to carry out a first-stage reaction, co-precipitating to obtain a first precursor with a particle size of X1; then taking the slurry clear liquid of the first precursor as the base solution, adjusting the solid content, and continuously introducing the nickel-cobalt-manganese mixed salt solution, the precipitant, the complexing agent, and a tungsten-gallium-magnesium mixed salt solution to carry out a second-stage reaction, co-precipitating to obtain the large-particle cathode material precursor with a particle size of X0.

[0010] In an optional implementation, X0 = 6 μm ~ 15 μm, X1:X0 = 1: (1.5 ~ 3).

[0011] In an optional embodiment, the concentration of metal ions in the nickel-cobalt-manganese mixed salt solution is 0.1 mol / L to 2.5 mol / L.

[0012] In an optional embodiment, the precipitant is a 5 mol / L to 15 mol / L sodium hydroxide solution.

[0013] In an optional embodiment, the complexing agent is an aqueous ammonia solution of 5 mol / L to 10 mol / L.

[0014] In an optional embodiment, the zirconium ion concentration of the zirconium salt solution is 0.01 mol / L to 0.1 mol / L.

[0015] In an optional embodiment, the aluminum salt solution is a sodium aluminate solution with an aluminum content of 0.01 mol / L to 0.2 mol / L.

[0016] In an optional embodiment, the tungsten-gallium-magnesium mixed salt solution has a tungsten ion concentration of 0.01~0.1 mol / L, a gallium ion concentration of 0.01~0.1 mol / L, and a magnesium ion concentration of 0.01~0.1 mol / L.

[0017] In an optional embodiment, during the first stage of the reaction, the temperature of the base liquid is maintained at 30°C to 80°C; In an optional implementation, prior to the first stage reaction, the concentration of complexed ions in the substrate is controlled to be 0.1 mol / L to 1.0 mol / L, and the pH is 9 to 12.

[0018] In an optional implementation, the solid content of the bottom liquid is adjusted to 10-150 g / L before the second stage reaction.

[0019] In an optional embodiment, both the first-stage reaction and the second-stage reaction are carried out under stirring conditions.

[0020] In an optional embodiment, the content of doped ions zirconium and aluminum in the first stage reaction is controlled to be 500~5000 ppm.

[0021] In an optional embodiment, the content of doped ions tungsten, magnesium, and gallium in the second stage reaction is controlled to be 500~5000 ppm.

[0022] In an optional embodiment, the preparation method further includes dehydrating the precursor slurry obtained from the second stage reaction to obtain a filter cake with a water content of 5% to 20%, washing the obtained filter cake by centrifugation with 1 to 10 times its weight of alkaline solution, washing it by centrifugation several times with 1 to 10 times its weight of deionized water, and after the content of various impurities meets the standard, centrifuging to dehydrate the filter cake and then drying it.

[0023] Thirdly, the present invention provides a cathode material obtained by sintering the large-particle cathode material precursor described in any of the foregoing embodiments.

[0024] Fourthly, the present invention provides the application of the cathode material as described in the foregoing embodiments in the preparation of cathodes or secondary batteries.

[0025] This invention offers the following advantages: By controlling the morphology and structure of the large-particle cathode material precursor, a radially ordered arrangement of internal grains is achieved, constructing a microstructure with a gradient increase in grain size from the inside out. This microstructure design with ordered gradient characteristics significantly enhances the structural stability of the precursor material. Furthermore, the large-particle cathode material precursor exhibits a loose secondary particle morphology with high porosity, possessing both large particle size and excellent comprehensive performance. Therefore, the above structural design effectively solves the common particle cracking problem in the synthesis process and subsequent calcination preparation of cathode materials from high-nickel and ultra-high-nickel cathode material precursors, thereby significantly improving the material's process stability and electrochemical performance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the large-particle cathode material precursor according to an embodiment of the present invention; Figure 2 This is a SEM image of the large-particle cathode material precursor of Example 1 of the present invention; Figure 3 This is a SEM image of the cross-section of the large-particle cathode material precursor of Embodiment 1 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0029] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0030] In the description of this invention, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0031] Some embodiments of the present invention provide a large-particle cathode material precursor, which is a porous secondary particle formed by primary grain stacking. The internal grains are arranged radially, and the grain size gradually increases from the inside to the outside. The particle size of the large-particle cathode material precursor is 6μm~15μm, and its structure is as follows: Figure 1 As shown.

[0032] By precisely controlling the morphology and structure of the large-particle cathode material precursor, a radially ordered arrangement of internal grains was successfully achieved, constructing a unique microstructure with a gradient increase in grain size from the inside out. This microstructure design with ordered gradient characteristics significantly improves the structural stability of the precursor material. Furthermore, the large-particle cathode material precursor exhibits a loose secondary particle morphology with high porosity, maintaining a large particle size while possessing excellent overall performance. Based on the above structural optimization strategy, the particle cracking problem commonly encountered in the synthesis process and subsequent calcination preparation of high-nickel and ultra-high-nickel cathode material precursors was effectively solved, thereby significantly improving the material's process stability and electrochemical performance.

[0033] In some embodiments, the chemical structural formula of the large-particle cathode material precursor is Ni. x Co y Mn （1-x-y）M(OH)₂, where 0.8 ≤ x < 1.0, 0 < y < 0.2, and M is a doping element, including Zr, Al, W, Ca, and Mg. The large-particle cathode material precursor consists of a core doped with Zr and Al, and a shell doped with W, Ca, and Mg. The doping concentrations of Zr and Al in the core are both 500~5000 ppm, for example, 500 ppm, 600 ppm, 800 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm. The doping levels of W, Ca, and Mg in the shell are 500 to 5000 ppm, such as 500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, or 5000 ppm.

[0034] Introducing zirconium (Zr) and tungsten (W) significantly enhances the structural and thermal stability of the material. Simultaneously, doping with aluminum (Al) and magnesium (Mg) optimizes electronic conductivity and effectively suppresses electrolyte decomposition reactions. Furthermore, calcium (Ca) primarily improves material performance by stabilizing the layered crystal structure and suppressing cation mixing. Based on the precise control of this multi-element synergistic doping strategy, the corresponding cathode material prepared from this precursor exhibits significantly improved electrochemical performance.

[0035] In some embodiments, the doping ratio of Zr to Al is (1~5):(1~5), such as 1:1, 1:2, 1:3, 1:4, 1:5, 5:1, 4:1, 3:1 or 2:1, etc., preferably (1~2):(1~2). The doping ratio of W, Ca and Mg is (1~5):(1~5):(1~5), such as 1:1:1, 1:2:2, 1:3:1, 1:2:1, etc., preferably (1~2):(1~2):(1~2).

[0036] Furthermore, some embodiments of the present invention also provide a method for preparing a large-particle cathode material precursor as described in any of the foregoing embodiments, comprising: continuously introducing a nickel-cobalt-manganese mixed salt solution, a precipitant, a complexing agent, a zirconium salt solution, and an aluminum salt solution into a base solution containing a complexing agent and a precipitant to carry out a first-stage reaction, co-precipitating to obtain a first precursor with a particle size of X1; then taking the slurry clear liquid of the first precursor as the base solution, adjusting the solid content, and continuously introducing the nickel-cobalt-manganese mixed salt solution, the precipitant, the complexing agent, and a tungsten-gallium-magnesium mixed salt solution to carry out a second-stage reaction, co-precipitating to obtain the large-particle cathode material precursor with a particle size of X0.

[0037] Specifically, some embodiments of the present invention provide a method for preparing the large-particle cathode material precursor, which includes the following steps: S1. Preparation of reaction raw materials and reagents.

[0038] (1) Prepare a mixed metal salt solution with a concentration of 0.1~2.5 mol / L using deionized water, using nickel sulfate, cobalt sulfate and manganese sulfate in a certain proportion.

[0039] (2) Prepare a sodium hydroxide solution with a concentration of 5~15 mol / L using deionized water as a precipitant.

[0040] (3) Dilute ammonia water to 5~10 mol / L with deionized water as a complexing agent.

[0041] (4) Dissolve the zirconium raw materials (water-soluble raw materials such as zirconium oxychloride, zirconium sulfate, zirconium nitrate, etc.) in deionized water to form a zirconium salt solution with a zirconium ion concentration of 0.01~0.1mol / L.

[0042] (5) Prepare a sodium aluminate solution with an aluminum content of 0.01~0.2 mol / L using deionized water, sodium hydroxide and aluminum sulfate, as an aluminum salt solution.

[0043] (6) Dissolve water-soluble tungsten, gallium and magnesium raw materials in deionized water to form a mixed solution, which is a tungsten gallium magnesium mixed salt solution, wherein the concentrations of each ion are as follows: tungsten ion concentration: 0.01~0.1mol / L, gallium ion concentration: 0.01~0.1mol / L, magnesium ion concentration: 0.01~0.1mol / L.

[0044] S2, Proceed to the first stage of the reaction.

[0045] Add 1 / 4 to 1 / 2 of the effective volume of the reactor to pure water, purge with nitrogen to replace air, turn on stirring and heating, and stabilize the stirring rate and the temperature inside the reactor at a certain value. Add complexing agent and precipitant, and adjust the concentration of complexed ions and pH value of the bottom liquid to the required value.

[0046] In some implementations, the temperature of the base solution is maintained at 30°C to 80°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, or 80°C, meaning the first-stage reaction is controlled within this temperature range. If the temperature is too low, the collision frequency between ions is low, the nucleation rate is slow, and the crystals have more time to grow, which may result in particles with larger diameters and smaller specific surface areas. Furthermore, the slow ion diffusion can easily lead to uneven local concentrations and may cause component segregation. If the temperature is too high, the nucleation rate increases sharply, resulting in the simultaneous generation of a large number of crystal nuclei. These nuclei may aggregate before they have enough time to grow, forming particles with small diameters, large specific surface areas, and a tendency to agglomerate. High temperatures may also accelerate the volatilization and decomposition of ammonia (the complexing agent), reducing the complexing effect; they may also cause transition metal ions to hydrolyze and form hydroxide precipitates, introducing impurities.

[0047] In some implementations, the concentration of complexing ions in the substrate is controlled to be between 0.1 mol / L and 1.0 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, or 1 mol / L. If the concentration of complexing ions is too low, the complexing ability will be insufficient, and most metal ions will exist in a free state. High concentrations result in a strong reaction driving force, leading to extremely fast nucleation rates, small particle size, poor sphericity, and even amorphous or irregular morphologies. It also easily generates impurity phases such as ferric hydroxide and aluminum hydroxide. Conversely, if the concentration of complexing ions is too high, the metal ions are tightly complexed, significantly reducing the effective concentration, noticeably slowing the reaction rate, and requiring a longer time to complete precipitation, thus reducing production efficiency. Furthermore, high concentrations of complexing agents may increase the viscosity of the system, causing uneven ion diffusion and affecting the uniformity of particle growth.

[0048] In some implementations, the pH is controlled to be 9–12, such as 9, 9.5, 10, 10.5, 11, 11.5, or 12. Within this range, metal ions can react with a precipitant (such as NaOH) at a suitable rate to form a precursor with high crystallinity, good sphericity, and uniform particle size.

[0049] A nickel-cobalt-manganese mixed salt solution, precipitant, complexing agent, zirconium salt solution, and aluminum salt solution are continuously added to the reactor at a certain flow rate and ratio to carry out the first stage reaction, and co-precipitate to obtain the first precursor with the required particle size X1; the process controls the amount of zirconium and magnesium doping ions by controlling the feed rate of zirconium salt solution and aluminum salt solution.

[0050] In some embodiments, the content of doped ions zirconium and aluminum in the first stage reaction is controlled to be 500~5000ppm, for example 500ppm, 600ppm, 800ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm, 4500ppm or 5000ppm.

[0051] S3, proceed with the second stage reaction.

[0052] A certain volume of the slurry clear liquid of the first precursor produced in the first stage reaction is taken as the base liquid, and a certain amount of the first precursor is added to control the solid content of the slurry in the reactor at 10~150g / L; then, the mixed salt solution, precipitant, complexing agent and auxiliary raw material C solution are continuously added to the reactor at a certain flow rate and ratio to co-precipitate and obtain the precursor slurry with the required particle size X0; the doping amount of each dopant ion is controlled by controlling the feed rate of the tungsten gallium magnesium mixed salt solution and the concentration of each element ion in the tungsten gallium magnesium mixed salt solution.

[0053] In some embodiments, X0 = 6 μm to 15 μm, and X1:X0 = 1:(1.5 to 3). In some embodiments, the second-stage reaction controls the content of doped ions tungsten, magnesium, and gallium to be 500 to 5000 ppm, for example, 500 ppm, 600 ppm, 800 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, or 5000 ppm.

[0054] It should be noted that, through extensive experiments and systematic research, the inventors innovatively discovered that in the co-precipitation reaction process, the appropriate introduction of zirconium (Zr) and magnesium (Mg) elements can effectively promote grain refinement growth; while appropriate doping of tungsten (W), magnesium (Mg), and gallium (Ga) elements helps to coarsen the grain size. Based on this discovery, by designing a two-stage reaction process and precisely controlling the doping strategy of different elements, the radially ordered arrangement of grains inside the cathode material precursor was successfully achieved. This innovative process ultimately constructs a microstructure with a unique gradient structure—the grain size exhibits a continuously increasing distribution characteristic from the inside to the outside along the radial direction, thereby preparing a cathode material precursor with a large particle size and a highly porous and loose structure, avoiding the spheroidization problem that is prone to occur in the synthesis process of high-nickel / ultra-high-nickel precursors and in the process of using precursors as cathode materials.

[0055] In some embodiments, both the first-stage reaction and the second-stage reaction are carried out under stirring conditions. For example, the stirring speed can be selected as 500~1000 rpm.

[0056] S4. Impurity removal treatment.

[0057] The precursor slurry obtained from the second stage reaction is dehydrated to obtain a filter cake with a water content of 5% to 20%. The obtained filter cake is centrifuged and washed with 1 to 10 times its weight of alkaline solution, and then centrifuged and washed several times with 1 to 10 times its weight of deionized water. After the content of various impurities meets the standard, the filter cake is centrifuged and dehydrated to obtain a filter cake, and then dried.

[0058] In some embodiments, the drying temperature is 80~110℃ and the drying time is 2~24h.

[0059] Some embodiments of the present invention also provide a cathode material obtained by sintering the large-particle cathode material precursor described in any of the foregoing embodiments.

[0060] Some embodiments of the present invention also provide the application of the cathode material as described in the foregoing embodiments in the preparation of cathodes or secondary batteries.

[0061] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0062] Example 1 This embodiment provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 8 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to a concentration of 5 mol / L as a complexing agent; dissolve zirconium oxychloride in deionized water to prepare a zirconium salt solution with a zirconium ion concentration of 0.05 mol / L; prepare a sodium aluminate solution with an aluminum content of 0.05 mol / L using deionized water, sodium hydroxide, and aluminum sulfate as an aluminum salt solution; dissolve water-soluble tungsten, gallium, and magnesium raw materials in deionized water to prepare a mixed solution as a tungsten-gallium-magnesium mixed salt solution, wherein the concentrations of each ion are: tungsten ion concentration: 0.05 mol / L, gallium ion concentration: 0.05 mol / L, and magnesium ion concentration: 0.05 mol / L.

[0063] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0064] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2 L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value. The feed flow rate of the zirconium salt solution is controlled at a doping amount of 2000 ppm, and the feed flow rate of the aluminum salt solution is controlled at a doping amount of 1500 ppm. Co-precipitation is performed to obtain the first precursor with the required particle size of 5 μm.

[0065] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the base liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel cobalt manganese mixed metal salt solution at 4 L / h, adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and control the feed rate of the tungsten gallium magnesium mixed salt solution at 1000 ppm of each element doping amount, and continuously add it into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers; the process controls the doping amount of each doping ion by controlling the feed rate of the tungsten gallium magnesium mixed salt solution and the concentration of each element ion in the tungsten gallium magnesium mixed salt solution.

[0066] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0067] The morphology of the obtained large-particle cathode material precursor was observed using a scanning electron microscope. Figure 2 As shown. Its cross-sectional SEM image is as follows. Figure 3 As shown, it is clear that the internal grains exhibit a gradient structure from the inside out.

[0068] Example 2 This embodiment provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 5 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to a concentration of 5 mol / L as a complexing agent; dissolve zirconium oxychloride in deionized water to prepare a zirconium salt solution with a zirconium ion concentration of 0.05 mol / L; prepare a sodium aluminate solution with an aluminum content of 0.05 mol / L using deionized water, sodium hydroxide, and aluminum sulfate as an aluminum salt solution; dissolve water-soluble tungsten, gallium, and magnesium raw materials in deionized water to prepare a mixed solution as a tungsten-gallium-magnesium mixed salt solution, wherein the concentrations of each ion are: tungsten ion concentration: 0.05 mol / L, gallium ion concentration: 0.05 mol / L, and magnesium ion concentration: 0.05 mol / L.

[0069] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0070] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2 L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value. The feed flow rate of the zirconium salt solution is controlled at a doping amount of 5000 ppm, and the feed flow rate of the aluminum salt solution is controlled at a doping amount of 5000 ppm. Co-precipitation is performed to obtain the first precursor with the required particle size of 5 μm.

[0071] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the base liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel cobalt manganese mixed metal salt solution at 4 L / h, adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and control the feed rate of the tungsten gallium magnesium mixed salt solution at 1000 ppm of each element doping amount, and continuously add it into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers; the process controls the doping amount of each doping ion by controlling the feed rate of the tungsten gallium magnesium mixed salt solution and the concentration of each element ion in the tungsten gallium magnesium mixed salt solution.

[0072] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0073] Example 3 This embodiment provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 8 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to a concentration of 5 mol / L as a complexing agent; dissolve zirconium oxychloride in deionized water to prepare a zirconium salt solution with a zirconium ion concentration of 0.05 mol / L; prepare a sodium aluminate solution with an aluminum content of 0.05 mol / L using deionized water, sodium hydroxide, and aluminum sulfate as an aluminum salt solution; dissolve water-soluble tungsten, gallium, and magnesium raw materials in deionized water to prepare a mixed solution as a tungsten-gallium-magnesium mixed salt solution, wherein the concentrations of each ion are: tungsten ion concentration: 0.05 mol / L, gallium ion concentration: 0.05 mol / L, and magnesium ion concentration: 0.05 mol / L.

[0074] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0075] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2 L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value. The feed flow rate of the zirconium salt solution is controlled at a doping amount of 2000 ppm, and the feed flow rate of the aluminum salt solution is controlled at a doping amount of 1500 ppm. Co-precipitation is performed to obtain the first precursor with the required particle size of 5 μm.

[0076] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the base liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel cobalt manganese mixed metal salt solution at 4 L / h, adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and control the feed rate of the tungsten gallium magnesium mixed salt solution at 5000 ppm of each element doping amount, and continuously add it into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers; the process controls the doping amount of each doping ion by controlling the feed rate of the tungsten gallium magnesium mixed salt solution and the concentration of each element ion in the tungsten gallium magnesium mixed salt solution.

[0077] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0078] Comparative Example 1 (Undoped) This comparative example provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 8 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to 5 mol / L as a complexing agent.

[0079] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0080] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value of the reaction. The first precursor with a particle size of 5μm is obtained by co-precipitation.

[0081] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the bottom liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel-cobalt-manganese mixed metal salt solution at 4 L / h, and adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and continuously add them into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers.

[0082] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0083] Comparative Example 2 (No core doping, outer layer doping) This comparative example provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 8 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to 5 mol / L as a complexing agent.

[0084] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0085] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value of the reaction. The first precursor with a particle size of 5μm is obtained by co-precipitation.

[0086] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the base liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel cobalt manganese mixed metal salt solution at 4 L / h, adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and control the feed rate of the tungsten gallium magnesium mixed salt solution at 1000 ppm of each element doping amount, and continuously add it into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers; the process controls the doping amount of each doping ion by controlling the feed rate of the tungsten gallium magnesium mixed salt solution and the concentration of each element ion in the tungsten gallium magnesium mixed salt solution.

[0087] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0088] Comparative Example 3 (nuclear doping, outer layer undoped) This comparative example provides a method for preparing a large-particle cathode material precursor, which includes the following steps: (1) Prepare a nickel-cobalt-manganese mixed metal salt solution with a concentration of 1.5 mol / L and a ratio of 90:05:05 using deionized water; prepare a sodium hydroxide solution with a concentration of 8 mol / L using deionized water as a precipitant; dilute ammonia water with deionized water to 5 mol / L as a complexing agent.

[0089] (2) Add 1 / 2 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring at 700 rpm, maintain the temperature of the reaction system at 60°C, add complexing agent and precipitant, adjust the concentration of complexed ions in the bottom liquid to 0.45 mol / L, and the pH value to 11.5.

[0090] (3) First stage reaction: Under the conditions of step (2), the mixed metal salt solution is fed at a flow rate of 2L / h. The flow rates of the precipitant and complexing agent are adjusted according to the required pH and ammonia value. The feed flow rate of the zirconium salt solution is controlled at a doping amount of 5000ppm, and the feed flow rate of the aluminum salt solution is controlled at a doping amount of 5000ppm. The first precursor with a particle size of 5μm is obtained by co-precipitation.

[0091] (4) Second stage reaction: Take 1 / 2 of the volume of the reactor as the clear liquid of the first precursor produced in the first stage reaction as the bottom liquid, add a certain amount of the first precursor, and control the solid content of the slurry in the reactor at 100 g / L; then, feed with a nickel-cobalt-manganese mixed metal salt solution at 4 L / h, and adjust the flow rate of the precipitant and complexing agent according to the required pH and ammonia value of the reaction, and continuously add them into the reactor to co-precipitate and obtain the required precursor slurry with a particle size of 10 micrometers.

[0092] (5) The obtained precursor slurry was dehydrated to obtain a filter cake with a water content of 5%~20%. The obtained filter cake was washed by centrifugation with 5 times its weight of alkaline solution, and then washed by centrifugation several times with 5 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation. The dried product was obtained by drying at 110℃ for 12 hours.

[0093] The large-particle cathode material precursors of the examples and comparative examples were sintered to obtain cathode materials. The specific sintering conditions were as follows: the prepared precursor material was mixed with lithium source (LiOH·H2O) in a certain proportion (Li / (Ni+Co+Mn)=1.04) and calcined at 800℃ for 20h to finally obtain cathode materials, and then the electrochemical performance was measured.

[0094] The performance of each cathode material obtained by sintering was tested. The specific test methods are as follows: The obtained positive electrode material was fabricated into a positive electrode sheet, which was then assembled with the negative electrode material into a CR2025 coin cell. Electrical performance data was tested. Initial efficiency = (0.1C initial discharge capacity / 0.1C initial charge capacity) * 100%; where the charge / discharge voltage window is 2.7~4.3V. Rate performance was tested according to a charge / discharge program of 0.1C*3 + 0.2C*3 + 0.5C*3 + 1.0C*3.

[0095] The test results are shown in Table 1.

[0096]

[0097] In summary, by rationally designing the precursor material structure, a large-particle precursor structure suitable for high-nickel and ultra-high-nickel systems is proposed, aiming to improve its structural stability and effectively avoid the ball-breaking problem that occurs in the preparation and application of large-particle precursors and their corresponding cathode materials. Simultaneously, by introducing specific doping elements, the morphology and microstructure of the precursor can be controlled, further enhancing the structural stability and overall electrochemical performance of the material. Based on this, a synthetic technique for the large-scale preparation of high-nickel / ultra-high-nickel large-particle precursors has been developed, providing technical support for the research and industrialization of high-performance lithium-ion battery cathode materials.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A large-particle cathode material precursor, characterized in that, The large-particle cathode material precursor is a porous secondary particle formed by primary grain stacking. Its internal grains are arranged radially, and the grain size gradually increases from the inside to the outside. The particle size of the large-particle cathode material precursor is 6μm~15μm.

2. The large-particle cathode material precursor according to claim 1, characterized in that, The chemical structural formula of the large-particle cathode material precursor is Ni. x Co y Mn （1-x-y） M(OH)2, where 0.8≤x<1.0, 0<y<0.2, and M is a doping element, including Zr, Al, W, Ca, and Mg.

3. The large-particle cathode material precursor according to claim 2, characterized in that, The large-particle cathode material precursor includes a core doped with Zr and Al and a shell doped with W, Ca and Mg. The doping amount of Zr and Al in the core is 500~5000ppm, and the doping ratio of Zr to Al is (1~5):(1~5). The doping amount of W, Ca and Mg in the shell is 500~5000ppm, and the doping ratio of W, Ca and Mg is (1~5):(1~5):(1~5).

4. A method for preparing a large-particle cathode material precursor as described in any one of claims 1 to 3, characterized in that, The process includes: continuously introducing a nickel-cobalt-manganese mixed salt solution, a precipitant, a complexing agent, a zirconium salt solution, and an aluminum salt solution into a base solution containing a complexing agent and a precipitant to carry out a first-stage reaction, co-precipitating to obtain a first precursor with a particle size of X1; then taking the slurry clear liquid of the first precursor as the base solution, adjusting the solid content, and continuously introducing the nickel-cobalt-manganese mixed salt solution, the precipitant, the complexing agent, and a tungsten-gallium-magnesium mixed salt solution to carry out a second-stage reaction, co-precipitating to obtain the large-particle cathode material precursor with a particle size of X0.

5. The method for preparing the large-particle cathode material precursor according to claim 4, characterized in that, X0=6μm~15μm, X1: X0=1: (1.5~3).

6. The method for preparing the large-particle cathode material precursor according to claim 4, characterized in that, The concentration of metal ions in the nickel-cobalt-manganese mixed salt solution is 0.1 mol / L to 2.5 mol / L; And / or, the precipitant is a 5 mol / L to 15 mol / L sodium hydroxide solution; And / or, the complexing agent is a 5 mol / L to 10 mol / L ammonia solution; And / or, the zirconium ion concentration of the zirconium salt solution is 0.01 mol / L to 0.1 mol / L; And / or, the aluminum salt solution is a sodium aluminate solution with an aluminum content of 0.01 mol / L to 0.2 mol / L; And / or, in the tungsten-gallium-magnesium mixed salt solution, the concentration of tungsten ions is 0.01~0.1 mol / L, the concentration of gallium ions is 0.01~0.1 mol / L, and the concentration of magnesium ions is 0.01~0.1 mol / L.

7. The method for preparing the large-particle cathode material precursor according to claim 4, characterized in that, During the first stage of the reaction, the temperature of the base liquid was maintained at 30℃~80℃; And / or, before the first stage reaction, control the concentration of complexed ions in the substrate solution to be 0.1 mol / L to 1.0 mol / L and the pH to be 9 to 12; And / or, before the second stage reaction, adjust the solid content of the bottom liquid to 10~150g / L; And / or, both the first-stage and second-stage reactions are carried out under stirring conditions; And / or, in the first stage of the reaction, the content of doped ions zirconium and aluminum is controlled to be 500~5000 ppm; And / or, in the second stage of the reaction, the content of doped ions tungsten, magnesium, and gallium is controlled to be 500~5000 ppm.

8. The method for preparing the large-particle cathode material precursor according to any one of claims 4 to 7, characterized in that, It also includes dehydrating the precursor slurry obtained from the second stage reaction to obtain a filter cake with a water content of 5% to 20%, washing the obtained filter cake by centrifugation with 1 to 10 times its weight of alkaline solution, washing it by centrifugation several times with 1 to 10 times its weight of deionized water, and after the content of various impurities meets the standard, centrifuging to dehydrate and obtaining a filter cake, and then drying it.

9. A positive electrode material, characterized in that, It is obtained by sintering the large-particle cathode material precursor as described in any one of claims 1 to 3.

10. The application of the cathode material as described in claim 9 in the preparation of cathodes or secondary batteries.

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