Small-particle-size ternary precursor and preparation method thereof

Abstract

The invention provides a small-particle-size ternary precursor and a preparation method thereof, and relates to the technical field of lithium batteries. The chemical formula of the small-granularity ternary precursor is Ni < x > Co < y > Mn < z > (OH) < 2 >; wherein 0.92 < = x < = 0.98, 0.02 < = y < = 0.06, 0 < = z < = 0.02, and x + y + z = 1; the particle shape of the small-particle-size ternary precursor is spherical or sphere-like, and the sphericity degree of the small-particle-size ternary precursor is not less than 0.89. According to the high-nickel small-particle-size ternary precursor provided by the invention, the balance of electrochemical performance and thermal stability is realized by regulating and controlling the metal molar ratio. The small-particle-size precursor particles are spherical or sphere-like, the sphericity degree is not smaller than 0.89, the problem that the high-nickel small-particle-size precursor particles are prone to particle aggregation due to the small particle size is solved, the fluidity and the compaction density are improved, the coating uniformity is improved, the breakage rate is reduced, and therefore the consistency and the yield of the material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium batteries, in particular to a small particle size ternary precursor and a preparation method thereof. BACKGROUND

[0002] Lithium ion batteries have been widely used in new energy vehicles, portable electronic devices and energy storage systems due to their high energy density, long cycle life and excellent safety performance. The positive electrode material is a key component that determines the performance of the battery. Among them, ternary materials are widely used because of their high capacity and good thermal stability. The performance of ternary positive electrode materials is highly dependent on the morphology, particle size distribution and composition uniformity of the precursor. Especially in high-energy application scenarios such as solid-state batteries, higher requirements are put forward for the sphericity, particle size control and dispersibility of the precursor to achieve higher compaction density and better electrochemical reaction uniformity.

[0003] Currently, there are many technical solutions for the preparation of ternary precursors. For example, some technical solutions add auxiliary particles to the co-precipitation system to enhance the mechanical collision frequency between particles during the reaction process, promote the formation of good sphericity and dispersibility of particles in a short time; some methods use unconventional complexing agent systems to achieve low-temperature synthesis of ultra-small particle size particles, and also consider particle morphology control; another process controls the kinetic conditions of nucleation-growth stage, and gradually increases the solid-liquid ratio and prolongs the friction contact time, etc., to improve the density and structure uniformity of the precursor. These methods achieve a certain degree of particle size narrowing, sphericity improvement and structure control in the laboratory or pilot stage, and become beneficial exploration in the development of ternary materials.

[0004] However, the existing technology still has many limitations in actual industrial application. The process route using mechanical auxiliary collision often needs to introduce additional particles or devices, which not only increases the complexity of the system, but also has the problems of impurity introduction and difficulty in post-processing. At the same time, this kind of process has high requirements for stirring equipment, reaction scale and stability of parameter control, which is easy to cause poor batch consistency. Although the process using organic complexing agent performs well in morphology control, its impact on the environment cannot be ignored, and the waste liquid treatment process is complex, which is difficult to meet the requirements of green manufacturing. And the process route that depends on high concentration slurry or multi-stage reaction may still have particle agglomeration in actual operation, which is difficult to achieve the unity of high sphericity and high dispersibility, limiting its application effect in high compaction density positive electrode materials.

[0005] In summary, the current preparation methods of ternary precursors generally face the following challenges: first, the process complexity is high, leading to poor process stability during scale-up production; second, there is a problem of insufficient environmental friendliness, especially in the emission control difficulty in organic system applications; third, the particle agglomeration phenomenon is difficult to effectively inhibit, which is more prominent under small particle size conditions, affecting the sphericity and dispersibility of the final product. These problems are particularly prominent in the development needs of high-performance lithium batteries, especially solid-state batteries, and new breakthroughs are needed in process simplification, greenization, and structure regulation capabilities. SUMMARY

[0006] The first object of the present application is to provide a small particle size ternary precursor and a preparation method thereof, which has high nickel content and high sphericity, and has high energy density and excellent processing performance, and is suitable for the preparation of high-performance lithium battery positive electrode materials.

[0007] In order to achieve the above object of the present application, the following technical scheme is adopted: In a first aspect, the present application provides a small particle size ternary precursor, the chemical formula of which is Ni x Co y Mn z (OH)2. Wherein, 0.92≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.02, and x+y+z=1. The particle shape of the small particle size ternary precursor is spherical or quasi-spherical, and the sphericity thereof is not less than 0.89.

[0008] In an optional embodiment, the small particle size ternary precursor is a secondary particle formed by spontaneous condensation of primary particles.

[0009] In an optional embodiment, the secondary particle has at least one of the following characteristics: A, particle size D 50 is 1.5 μm~2.8 μm; B, particle size span is 0.90<(D 90 -D 10 ) / D 50 <1.2; C, specific surface area is 20 m 2 / g~35 m 2 / g; D, tap density is 1.0 g / cm 3 ~1.8 g / cm 3 .

[0010] In a second aspect, the present application provides a preparation method of the small particle size ternary precursor as described in any one of the preceding embodiments, comprising: The metal salt mixed solution containing nickel source, cobalt source and manganese source, the alkali solution and the ammonia solution are introduced into the reaction system to be mixed, and under the reaction conditions of 40-60℃, pH 9.8-11.8 and alkalinity 1-5g / L, the small-particle-size ternary precursor is generated through complexation-coprecipitation reaction.

[0011] In optional embodiments, the nickel source includes at least one of nickel sulfate, nickel nitrate and nickel chloride; and / or, the cobalt source includes at least one of cobalt sulfate, cobalt nitrate and cobalt chloride; and / or, the manganese source includes at least one of manganese sulfate, manganese nitrate and manganese chloride; and / or, the total molar concentration of nickel, cobalt and manganese metal ions in the metal salt mixed solution is 1-3mol / L; and / or, the alkali solution includes sodium hydroxide solution and / or potassium hydroxide solution; the concentration of the sodium hydroxide solution is 8-12mol / L; and / or, the concentration of the ammonia solution is 5-8mol / L.

[0012] In optional embodiments, the complexation-coprecipitation reaction includes: The alkali solution and the ammonia solution are stirred and treated under a first protective atmosphere to prepare a reaction bottom solution; The metal salt mixed solution is introduced into the reaction bottom solution in stages, and the pH and alkalinity are adjusted by using the alkali solution to perform segmented reaction to generate the small-particle-size ternary precursor.

[0013] In optional embodiments, the preparation of the reaction bottom solution has at least one of the following characteristics: A. The first protective atmosphere is nitrogen or a mixture of nitrogen and air; B. The linear speed of the stirring treatment is 4-9m / s; C. The temperature during the stirring treatment is controlled at 40-60℃; D. The pH during the stirring treatment is controlled at 11.2-11.9.

[0014] In optional embodiments, the segmented reaction by adjusting the pH and alkalinity by using the alkali solution includes: In the first stage, the metal salt mixed solution is introduced into the reaction bottom solution at a flow rate of 20-50mL / min, and the alkali solution is introduced into the reaction system at a flow rate of 10-15mL / min to perform nucleation reaction, the pH is controlled at 11.60-11.70, and the reaction time is 10-30min; In the second stage, the flow rate of the alkali solution is reduced, the pH is controlled at 11.40-11.50, and the reaction is maintained for 8-16h. In the third stage, the flow rate of the mixed metal salt solution is adjusted to 100 mL / min to 120 mL / min, the pH is controlled at 11.00 to 11.30, and the adjustment is maintained for 8 hours to 16 hours; In the fourth stage, the flow rate of the mixed metal salt solution is adjusted to 150 mL / min to 180 mL / min, the pH of the reaction system is controlled at 10.60 to 10.80, and the adjustment is maintained for 8 hours to 16 hours, until the D 50 to 2.8 μm.

[0015] In an optional embodiment, during the reaction process of adjusting the pH and alkalinity by the alkali solution in stages, nitrogen is introduced at 0 hour to m hours; and / or, a mixture of nitrogen and air is introduced at m hours to n hours. wherein n > m, and 12 ≥ m ≥ 2.

[0016] In a third aspect, the application provides a positive electrode material, which is prepared based on the small-particle-size ternary precursor according to any one of the preceding embodiments.

[0017] In a fourth aspect, the application provides a positive electrode sheet, which comprises the positive electrode material according to the preceding embodiments.

[0018] In a fifth aspect, the application provides a battery, which comprises the positive electrode sheet according to the preceding embodiments.

[0019] In a sixth aspect, the application provides an electrical equipment, which comprises the battery according to the preceding embodiments.

[0020] The application provides a small-particle-size ternary precursor and a preparation method thereof. The small-particle-size ternary precursor has a chemical formula of Ni x Co y Mn z (OH)2; wherein 0.92 ≤ x ≤ 0.98, 0.02 ≤ y ≤ 0.06, 0 ≤ z ≤ 0.02, and x + y + z = 1, and belongs to a high-nickel content system. The high-nickel ternary system is widely used in high-energy-density lithium ion batteries due to its high reversible capacity. By reasonably adjusting the molar ratio of metals, the electrochemical performance and thermal stability can be considered, which provides a good chemical basis for the subsequent synthesis of high-performance ternary positive electrode materials.

[0021] Secondly, the particle morphology of the precursor is limited to spherical or spherical-like, and the sphericity is not less than 0.89. The high-sphericity particles have better fluidity and packing performance in the preparation process of the positive electrode material, which helps to improve the compaction density, improve the coating uniformity, and further improve the consistency and overall energy density of the electrode. In addition, the higher sphericity can effectively reduce the friction coefficient between particles, reduce the particle breakage caused by shearing in the processing process, and improve the yield and stability of the material.

[0022] In summary, by optimizing the chemical composition and particle morphology of the small-particle-size ternary precursor, the problem of particle agglomeration of the small-particle-size high-nickel precursor due to small particle size is improved, the process adaptability of the precursor in the electrode manufacturing process is improved, and the precursor is suitable for the preparation process of lithium battery positive electrode materials with high requirements for material structure and performance stability, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0024] Figure 1 SEM micro-morphology diagram of the product prepared in Example 1 of the present application; Figure 2 Particle sphericity measurement statistical diagram of the product prepared in Example 1 of the present application; Figure 3 SEM micro-morphology diagram of the product prepared in Example 2 of the present application; Figure 4 Particle sphericity measurement statistical diagram of the product prepared in Example 2 of the present application; Figure 5 Particle sphericity measurement statistical diagram of the product prepared in Example 3 of the present application; Figure 6 SEM micro-morphology diagram of the product prepared in Comparative Example 1 of the present application; Figure 7 Particle sphericity measurement statistical diagram of the product prepared in Comparative Example 1 of the present application; Figure 8 SEM micro-morphology diagram of the product prepared in Comparative Example 2 of the present application; Figure 9 Particle sphericity measurement statistical diagram of the product prepared in Comparative Example 2 of the present application. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0026] This application provides a small-particle-size ternary precursor, the chemical formula of which is Ni. x Co y Mn z (OH)2; wherein, 0.92≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.02, and x+y+z=1; the particle shape of the small-diameter ternary precursor is spherical or near-spherical, and its sphericity is not less than 0.89.

[0027] In the above, x, y, and z represent the molar proportions of nickel, cobalt, and manganese elements in the small-particle-size ternary precursor, respectively, and satisfy 0.92≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.02, and x+y+z=1.

[0028] This formulation creates a high-nickel ternary system with a nickel content of no less than 90%, which is beneficial for improving the specific capacity of subsequent cathode materials, thereby achieving higher energy density in lithium-ion batteries. Simultaneously, retaining a certain proportion of cobalt and manganese helps improve the material's thermal stability and structural integrity, enhancing cycle performance.

[0029] In the composition design of small-particle-size ternary precursors, by optimizing the molar ratio of the three metals Ni, Co, and Mn, both high capacity output and structural / thermal stability are taken into account, thereby achieving synergistic improvement among multiple performance parameters and laying the foundation for the subsequent preparation of high-energy-density and long-life cathode materials.

[0030] The particle morphology of the small-diameter ternary precursor is spherical or near-spherical, with a sphericity of not less than 0.89.

[0031] Specifically, sphericity is determined by the formula The calculation yielded the result. Here, A represents the projected area of ​​the particle, and P represents the perimeter. The closer this value is to 1, the closer the particle is to an ideal sphere.

[0032] The particle shape of the small particle size ternary precursor is spherical or spheroidal, and the spherical or spheroidal structure helps to improve the flowability and compaction performance of the particles, and is conducive to forming a uniform and dense structure in the process of preparing the electrode, thereby improving the consistency and compaction density of the electrode, and further optimizing the rate performance and energy density of the battery. In addition, the high sphericity structure can also reduce the risk of particle breakage during processing, and improve the processing stability and yield of the material.

[0033] In some embodiments, the small particle size ternary precursor is a secondary particle formed by spontaneous aggregation of primary particles.

[0034] The small particle size ternary precursor is a secondary particle formed by spontaneous aggregation of primary particles. This structure belongs to the typical "secondary particle aggregate" morphology. The primary particle refers to the basic nanoscale crystal grains directly generated by the coprecipitation reaction, which has a small size, a large surface area, and a high reactivity. Due to the high surface energy, these primary particles will spontaneously undergo oriented aggregation and connection during the reaction process, and will be aggregated into larger size secondary particles through short-range diffusion, interface lapping and other mechanisms, forming a spheroidal or spherical aggregate structure.

[0035] By controlling the crystallization kinetics (such as temperature, alkalinity, pH and salt flow rate changes, etc.), the oriented fusion of primary particles can be promoted, so that the secondary particles formed have a high sphericity and dispersity. This spontaneous aggregation method avoids the use of external granulation or template medium, simplifies the process flow, and reduces the risk of introducing impurities.

[0036] The use of a secondary particle structure formed by spontaneous aggregation of primary particles can simultaneously consider the compaction density and electrochemical activity of the material. On the one hand, the secondary particle size is moderate, which is conducive to the flowability and film-forming property of the subsequent positive electrode material; on the other hand, the porous structure composed of small particles inside can shorten the diffusion path of lithium ions and improve the rate performance. Therefore, this structure has wide application value in high energy density lithium battery materials.

[0037] In addition, this structure not only maintains good particle distribution uniformity, but also effectively improves the mechanical strength and thermal stability of the particles, reduces the risk of breakage during high-temperature calcination or slurry mixing. At the same time, the loose structure inside the secondary particles is conducive to improving the wettability of the material and the subsequent lithium ion diffusion rate, and has a significant promoting effect on the preparation of ternary positive electrode materials with high specific capacity and high power performance.

[0038] Moreover, the precursor has a spherical secondary particle structure composed of primary particles, which helps to simultaneously improve the compaction density and electrolyte wettability, construct efficient electron / ion transmission channels, and realize the synergistic optimization of structure design and electrochemical performance.

[0039] In some embodiments, the secondary particles have at least one of the following characteristics: A, particle size D 50 is 1.5 pm to 2.8 pm; for example, it can be 1.5 pm, 1.6 pm, 1.7 pm, 1.8 pm, 1.9 pm, 2.0 pm, 2.3 pm, 2.4 pm, 2.6 pm, 2.8 pm, etc.

[0040] D 50 is the median particle size of the particle population, which is an important parameter for characterizing the average size of the particles. Controlling D 50 in the range of 1.5 pm to 2.8 pm helps to balance the uniformity of the particle size and the lithium ion diffusion efficiency of the material.

[0041] In the preparation of small particle size ternary precursor, small particle size particles (such as D 50 < 4 pm) have significant advantages, such as being able to shorten the diffusion path of lithium ions in the particles, thereby improving the rate performance of the material, which is crucial for the performance improvement of high energy density lithium ion batteries. When the particle size is small, the migration path of lithium ions in the particles can be shortened, and the rate performance of the material can be improved; however, too small particle size can lead to too high specific surface area, which can easily cause side reactions, so it is important to set an appropriate particle size range.

[0042] However, it should be noted that small particle size high nickel particles face many challenges in the preparation process. Due to its high surface energy, the particles are prone to agglomeration, which not only reduces the sphericity of the particles, but also affects their dispersibility, thereby affecting the performance and consistency of the battery. In the traditional process, the sphericity of the particles prepared by the traditional process is usually only 70% to 80% when the particle size is less than 4 pm, which is difficult to meet the requirements of high-performance battery cathode materials. 50 < 4 pm, the sphericity is usually only 70% to 80%, which is difficult to meet the requirements of high-performance battery cathode materials.

[0043] In this embodiment, a series of innovative technical means are used to successfully overcome the above problems. For example, it can include but is not limited to the following technologies: in the preparation process, low temperature and low ammonium ion concentration reaction conditions are used, the flow of metal salt and the pH value are adjusted in stages, the reaction kinetics is optimized, and the growth process of the particles is more controllable. In addition, the mixture of nitrogen and air is introduced to further inhibit the agglomeration of the particles.

[0044] The synergistic effect of these technical means not only ensures the small particle size (D 50 is 1.5 pm to 2.8 pm), but also significantly improves the sphericity of the particles, which is not less than 0.89.

[0045] The particle structure with small particle size and high sphericity helps to improve the flowability and compaction performance of the particles, and can form a uniform and dense structure during the preparation of the electrode plate, improve the consistency and compaction density of the electrode, and further optimize the rate performance and energy density of the battery. In addition, the high sphericity structure can also reduce the risk of particle breakage during processing, improve the processing stability and yield of the material, and provide a strong guarantee for the preparation of high-performance lithium battery positive electrode materials.

[0046] The small particle size ternary precursor described in the embodiment is particularly suitable for the preparation of solid-state battery positive electrode materials due to its small particle size and high sphericity. In a solid-state battery, ion transport between the solid-state electrolyte and the active material mainly depends on the interface contact, so the small particle size of the precursor particles is beneficial to shorten the lithium ion diffusion path and improve the interface ion migration efficiency; the high sphericity helps to improve the packing density and interface contact uniformity of the particles, and reduces the interface impedance, thereby improving the rate performance and cycle stability of the battery. In addition, the particles with small particle size and high sphericity are easier to mix uniformly with the solid-state electrolyte, which helps to build a continuous and efficient ion conduction network, further improving the overall performance of the solid-state battery.

[0047] B, the particle size span is 0.90<(D 90 -D 10 ) / D 50 <1.2; wherein, (D 90 -D 10 ) / D 50 For example, it can be 1.0, 1.1, etc.

[0048] The particle size span reflects the uniformity of the particle distribution. Controlling the value in the range of 0.90-1.2 indicates that the particle distribution is relatively concentrated, which is beneficial to improve the consistency and flow performance of the material during processing, and avoid problems such as slurry sedimentation, uneven electrode thickness, etc. caused by too large particle size difference.

[0049] C, the specific surface area is 20m 2 / g-35m 2 / g; for example, it can be 20m 2 / g, 22m 2 / g, 24m 2 / g, 26m 2 / g, 28m 2 / g, 30m 2 / g, 31m 2 / g, 32m 2 / g, 33m 2 / g, 34m 2 / g, 35m 2 / g, etc.

[0050] The above specific surface area range is set to 20m 2 / g~35m 2 / g, aiming to provide a proper reaction interface, improve the reaction degree of the material with the lithium source during sintering and lithiation, and meanwhile, a specific surface area that is not too high helps to control the side reaction and maintain good electrochemical stability.

[0051] D, the tap density is 1.0g / cm 3 ~1.8g / cm 3 . For example, it can be 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.7g / cm 3 , 1.8g / cm 3 , etc.

[0052] The tap density is the density of the loose pile of particles, which is 1.0g / cm 3 ~1.8g / cm 3 , which helps to improve the compaction density and energy density of the electrode. Higher tap density can also improve the mechanical strength and forming consistency of the electrode sheet, and has a significant effect on the improvement of the energy density of the battery.

[0053] The multiple physical parameters defined above, which are around particle size, distribution, specific surface area and tap density, are key indicators for measuring the processing performance, electrochemical adaptability and structural stability of the ternary precursor. By at least meeting one of them, it can be ensured that the precursor has good practical application value and is suitable for the synthesis and manufacturing of high-performance lithium battery positive electrode materials.

[0054] In the embodiments of the present application, a preparation method of the small-particle-size ternary precursor according to any one of the preceding embodiments is provided, which comprises: Step S100, a mixed solution of metal salts containing nickel source, cobalt source and manganese source, an alkali solution and an ammonia solution are introduced into a reaction system to mix, under the reaction conditions of 40℃~60℃, pH 9.8~11.8 and alkalinity 1g / L~5g / L, a small-particle-size ternary precursor is generated through complexation-coprecipitation reaction. The above reaction temperature, for example, can be 40℃, 50℃, 60℃, etc. The above reaction pH, for example, can be 9.8, 9.9, 10.1, 10.2, 10.4, 10.6, 10.7, 10.8, 11.0, 11.2, 11.4, 11.6, 11.7, 11.8, etc.

[0055] In some implementations, the pH can be controlled between 10.60 and 11.70. For example, it can be 10.61, 10.62, 10.63, 10.64, 10.65, 10.68, 10.70, etc.

[0056] The alkalinity mentioned above can be, for example, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, etc.

[0057] The preparation method first utilizes ammonia water to form a stable complex with metal cations, and then controls the precipitation rate under appropriate alkaline conditions to allow the three metal ions to precipitate synergistically during the reaction, forming a hydroxide precursor with a uniform stoichiometric ratio.

[0058] The complexation of ammonia can stabilize the coordination environment of various metal ions in the system, prevent problems such as local supersaturation and non-uniform precipitation under alkaline conditions, thereby improving the chemical homogeneity and morphological consistency of the product.

[0059] Controlling the reaction temperature between 40℃ and 60℃ helps to suppress rapid crystal growth while ensuring the reaction rate, thereby improving the dispersibility and sphericity of the particles. Too high a temperature can easily lead to crystal coarsening and agglomeration, while too low a temperature will affect the efficiency of the reaction.

[0060] Maintaining a pH between 9.8 and 11.8 can regulate the precipitation rate of metal hydroxides, thereby affecting nucleation and crystal growth behavior. Within this pH range, the precipitation curves of various metal ions overlap, which is beneficial for achieving simultaneous precipitation and uniform nucleation, contributing to the consistency of precursor composition and morphology control.

[0061] In this embodiment, alkalinity is limited (i.e., ammonium ion NH4+). + The concentration is 1 g / L to 5 g / L. Lower alkalinity makes the precipitation process more gradual, promotes the evolution of particles into spherical shapes, and improves the sphericity and flowability of the final product.

[0062] The complexation-coprecipitation process described above can effectively control reaction kinetics and achieve multiple optimizations of particle size, sphericity, and dispersibility, providing an industrially feasible and controllable process route for preparing high-nickel, high-sphericity small-particle-size ternary precursors.

[0063] Firstly, in terms of raw material composition, a mixed solution of metal salts, an alkaline solution, and an ammonia solution are used in synergistic reaction to form stable complexes of metal ions and precipitate them simultaneously. This significantly improves the uniformity of the distribution of Ni, Co, and Mn elements in the product and avoids the problems of component drift and local enrichment.

[0064] Secondly, in terms of reaction condition control, the synergistic range of three key parameters, temperature (40℃~60℃), pH value (9.8~11.8) and alkalinity (1g / L~5g / L) is clearly defined. Compared with the single parameter control mode of pH or temperature in the traditional method, this method achieves a better balance between reaction thermodynamics and kinetics, significantly improves the sphericity and dispersity of the particles, and reduces the risk of agglomeration.

[0065] Moreover, this method does not require the introduction of additional templates or organic complexing agents, avoiding the introduction of impurities or environmental pollution caused by the use of hard microspheres or organic additives, and improving the green environmental protection and stability of industrialization from the source, reducing the post-processing cost.

[0066] In summary, the whole reaction system design takes into account the formation mechanism of key indicators such as small particle size, narrow particle size distribution and high sphericity, providing reliable process support for the preparation of small particle size ternary precursors with high performance, stable structure and strong processing adaptability, especially suitable for large-scale production of high-energy-density lithium-ion battery cathode materials.

[0067] In some embodiments, the nickel source includes nickel sulfate. In some embodiments, the cobalt source includes cobalt sulfate. In some embodiments, the manganese source includes manganese sulfate.

[0068] The above-mentioned nickel source can include nickel sulfate, the cobalt source can include cobalt sulfate, and the manganese source can include manganese sulfate. Such sulfate metal salts are easily soluble in water, have good reactivity and industrial applicability, and are the most common source of metal ions in the preparation of ternary cathode precursors.

[0069] By using these soluble sulfates, the stable distribution of metal ions in the aqueous phase can be ensured, thereby facilitating the uniformity and reaction rate control of the subsequent co-precipitation process.

[0070] In some embodiments, the total molar concentration of nickel, cobalt and manganese metal ions in the metal salt mixed solution is 1mol / L~3mol / L. For example, it can be 1mol / L, 2mol / L, 3mol / L, etc.

[0071] The concentration range of the total molar concentration ensures that there is enough metal ion concentration to maintain the continuity of the nucleation-growth reaction during the reaction process, and on the other hand, avoids the local supersaturation or agglomeration phenomenon caused by too high concentration, ensuring that the particle size and morphology are controlled within the ideal range.

[0072] In some embodiments, the alkali solution includes sodium hydroxide solution and / or potassium hydroxide solution.

[0073] In some embodiments, the concentration of the alkali solution, such as sodium hydroxide solution (potassium hydroxide solution), can be 8 mol / L to 12 mol / L. For example, it can be 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L, and the like.

[0074] In terms of the selection of the alkali solution, sodium hydroxide solution (potassium hydroxide solution) can be used as the main alkali source, and its concentration is set to 8 mol / L to 12 mol / L. A higher concentration of alkali solution helps to control the pH value of the reaction system within the target range (such as 9.8 to 11.8), ensuring that various metal ions are precipitated synchronously in a favorable precipitation interval. At the same time, a high concentration of alkali solution helps to control the precipitation rate and stabilize the particle size growth.

[0075] In some embodiments, the concentration of the ammonia solution is 5 mol / L to 8 mol / L. For example, it can be 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, and the like.

[0076] The ammonia solution acts as a complexing agent, and its concentration is controlled at 5 mol / L to 8 mol / L, which is conducive to the formation of stable ammonia complexes, especially the complexes formed with Ni 2+ , Co 2+ and other metal ions, which helps to regulate the release rate of metal ions during the reaction process, thereby affecting the nucleation density and particle uniformity. Appropriate complexing strength can also inhibit local supersaturation and uneven precipitation, promoting the formation of high-sphericity structures.

[0077] In some embodiments, the complexation-coprecipitation reaction includes: Step S1, the alkali solution, the ammonia solution, is stirred and treated under a first protective atmosphere to prepare a reaction bottom solution.

[0078] Step S2, the metal salt mixed solution is introduced into the reaction bottom solution in stages, and the pH and alkalinity of the reaction system are adjusted by the alkali solution to perform a segmented reaction, generating the small-particle-size ternary precursor.

[0079] In the above method, the alkali solution and the ammonia solution are first stirred and treated under a first protective atmosphere to form a reaction bottom solution; then the metal salt mixed solution is introduced into the reaction bottom solution in stages, and the pH and alkalinity of the reaction system are adjusted by the alkali solution to complete the segmented reaction process, finally forming the small-particle-size ternary precursor precipitate.

[0080] In the operation logic of "preparing the bottom solution and then introducing the feed in stages", the reaction of alkali and ammonia water in advance can establish a stable alkaline complexing environment, which is called "reaction bottom solution".

[0081] In this system, ammonia water and Ni 2+Co 2+ Mn 2+ The stable complex formed by the metal ions and the hydroxyl ions provides precipitation conditions, and the two work together to regulate the precipitation rate and stabilize the nucleation process, thereby significantly improving the chemical uniformity and controllability of the particle size of the particles.

[0082] The protective atmosphere (such as nitrogen) can avoid the participation of CO2 or O2 in the air in the reaction, prevent the change of the pH of the system or the oxidation of the metal ions, and help to improve the reaction repeatability and product stability, and is particularly suitable for the control of easily oxidized ions in a high-nickel system.

[0083] The use of the "staged" method of introducing the metal salt solution helps to achieve the separation control of nucleation and growth.

[0084] For example, a high pH value can be maintained in the initial stage to promote sufficient nucleation, and the pH can be gradually reduced in the subsequent stage to regulate the growth rate, thereby avoiding the generation of coarse particles or agglomerates. Through the dynamic adjustment of the alkali solution, the alkalinity and reaction kinetics parameters of the entire precipitation system are further fine controlled.

[0085] In summary, the above method realizes the comprehensive control of the particle morphology (sphericity), particle size distribution, chemical uniformity, and dispersity by first establishing a uniform complex alkaline reaction environment and then precisely controlling the reaction process, thereby providing a structured, stable, and controllable reaction path for preparing high-performance small-particle ternary precursors, and the method is suitable for pilot and industrial production.

[0086] In some embodiments, the preparation of the reaction bottom solution has at least one of the following characteristics: A. The first protective atmosphere is nitrogen or a mixture of nitrogen and air.

[0087] The use of nitrogen or a mixture of nitrogen and air as the protective atmosphere helps to inhibit the oxidation of metal ions, especially in a high-nickel ternary system, Ni 2+ is easily oxidized to Ni 3+ , which affects the stability of the precipitation rate and stoichiometric ratio. The introduction of an inert gas environment can improve the control accuracy and repeatability of the reaction system, and is beneficial to the realization of the consistency and batch stability of the product.

[0088] B. The linear velocity of the stirring treatment is 4 m / s to 9 m / s; for example, it can be 4 m / s, 5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s, and the like.

[0089] Maintaining a stirring linear velocity between 4 m / s and 9 m / s can significantly improve the mixing efficiency of materials in the liquid phase system and enhance the homogeneity of the reaction solution. A higher stirring linear velocity promotes thorough mixing of hydroxide ions and ammonia complexes in the solution, prevents localized pH deviations, and contributes to the synchronous and uniform growth of precursor particles during nucleation.

[0090] C. The temperature during the stirring process is controlled between 40℃ and 60℃; for example, it can be 40℃, 50℃, 60℃, etc.

[0091] In terms of temperature control, maintaining the stirring process at 40℃~60℃ can accelerate the complexation and initial nucleation reaction rate, improve the crystallinity of the generated particles, and at the same time inhibit the agglomeration or morphological distortion caused by excessively rapid precipitation, which is conducive to the spontaneous formation of subsequent spherical structures.

[0092] D. The pH during the stirring process is controlled between 11.2 and 11.9. For example, it can be 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, etc.

[0093] Maintaining the initial pH of the reaction substrate between 11.2 and 11.9 ensures the stability of Ni. 2+ Co 2+ and Mn 2+ By ensuring that metal ions are within a suitable precipitation window, the precipitation rate and complexation release rate are balanced, avoiding problems such as premature precipitation or incomplete precipitation, thereby improving the consistency of the proportions and chemical stability of the ternary components.

[0094] In some embodiments, step S2, which involves adjusting the pH and alkalinity of the alkaline solution in stages to carry out the reaction, includes: Step S21, the first stage, the metal salt mixed solution is introduced into the reaction base liquid at a flow rate of 20 mL / min to 50 mL / min, and the alkaline solution is introduced into the reaction system at a flow rate of 10 mL / min to 15 mL / min to carry out the nucleation reaction, the pH is controlled at 11.60 to 11.70, and the reaction time is 10 minutes to 30 minutes.

[0095] For example, the flow rate of a mixed metal salt solution can be 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, etc. The flow rate of an alkaline solution can be 10 mL / min, 11 mL / min, 12 mL / min, 13 mL / min, 14 mL / min, 15 mL / min, etc. The pH can be controlled to 11.60, 11.61, 11.62, 11.65, 11.68, 11.69, 11.70, etc. The reaction time can be 10 minutes, 20 minutes, 30 minutes, etc.

[0096] In the first stage, the lower metal salt and alkali solution flow (20-50 mL / min and 10-15 mL / min, respectively) are introduced together, the pH is controlled between 11.60-11.70, and maintained for 10-30 minutes, which promotes the formation of high-activity nucleation points in the reaction system. The uniform nucleation crystals formed in this stage provide a basis for subsequent particle growth, thereby avoiding uneven particle distribution and agglomeration problems.

[0097] For example, the nucleation reaction can be performed by feeding the metal salt at a flow rate of 30 mL / min and the alkali at a flow rate of 13 mL / min, and controlling the pH of the reaction system between 11.60-11.70, with a nucleation reaction time of 20 minutes.

[0098] In step S22, the second stage, the flow of the alkali solution is reduced, and the pH is controlled between 11.40-11.50, maintained for 8-16 hours.

[0099] For example, the pH can be 11.41, 11.42, 11.43, 11.44, 11.45, 11.48, 11.49, 11.50, etc.; and the reaction time can be 8, 9, 10, 11, 12, 13, 14, 15, 16, etc.

[0100] In the second stage, by reducing the flow of the alkali solution, the pH is slowly reduced to 11.40-11.50, and maintained for 8-16 hours, which helps to control the sustained growth rate of the crystal nucleus, and improves the size uniformity and internal density of the particles. Longer reaction time ensures the ordered perfection of the crystal structure, and reduces the defect density.

[0101] For example, in this step, the alkali flow can be reduced to slowly reduce the pH to 11.40-11.50, maintained for 12 hours.

[0102] In step S23, the third stage, the flow of the metal salt mixed solution is adjusted to 100-120 mL / min, the pH is controlled between 11.00-11.30, and maintained for 8-16 hours.

[0103] For example, the flow can be 100 mL / min, 110 mL / min, 120 mL / min, etc.; the pH can be 11.00, 11.10, 11.20, 11.30, etc.; and the reaction time can be 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, etc.

[0104] The third stage increases the flow rate of the metal salt solution to 100-120 mL / min while maintaining the pH at 11.00-11.30 to continue promoting the growth of particle size. The feed rate of this stage is matched with the alkalinity control, further strengthening the dense coating of the outer layer of the particles and the spherical evolution trend.

[0105] For example, this step can adjust the metal salt flow to 110 mL / min, and adjust the base flow to control the pH in the tank to maintain between 11.00 and 11.30.

[0106] Step S24, the fourth stage, the flow rate of the metal salt mixed solution is increased to 150-180 mL / min, the pH of the reaction system is controlled at 10.60-10.80, and maintained for 8-16 hours, until the D 50 1.5-2.8 μm.

[0107] For example, the flow rate can be 150 mL / min, 160 mL / min, 170 mL / min, 180 mL / min, etc.; the pH can be 10.60, 10.70, 10.80, etc.; the reaction time can be 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, etc.; the D 50 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, 2.1 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, etc.

[0108] The fourth stage again increases the flow rate of the metal salt solution to 150-180 mL / min and controls the pH value at 10.60-10.80 for 8-16 hours to further increase the particle size and stabilize it, so that the D50 of the final product is controlled in the range of 1.5-2.8 μm, which helps to meet the requirements of high compaction density and good processability.

[0109] For example, this step can adjust the metal salt flow to 160 mL / min after 24 hours of reaction, so that the D 50 1.5-2.8 μm.

[0110] Through the above multi-stage control strategy, the problems of wide particle size distribution, serious agglomeration and poor sphericity in traditional co-precipitation method can be effectively solved, the structural uniformity and yield of the material are significantly improved, and high-performance positive electrode material is provided. This scheme is suitable for industrial scale continuous preparation, has good repeatability and scalability.

[0111] In the process of preparing small particle size ternary precursors, the feeding strategy of metal salt and alkali solution has a significant influence on the nucleation rate, growth behavior and final particle size distribution of the particles. In order to realize precise control of the particle morphology and particle size, the present application adopts a multi-stage segmented feeding mode, that is, the feeding flow rate of metal salt and alkali solution is set according to different stages of the reaction process, and the pH value of the reaction system is dynamically controlled.

[0112] Specifically, a large number of nucleation points are formed by rapidly passing in the metal salt and alkali solution at the initial nucleation stage to promote the generation of uniform initial particles; then, in the particle growth stage, the alkali solution addition rate is gradually reduced, while the metal ion concentration is maintained and the pH value is slowly reduced, so as to avoid particle agglomeration and rapid particle size growth; finally, in the particle maturation stage, the metal salt feeding rate is gradually increased, the pH value of the system is slowly reduced, and the particles are uniformly grown to the target particle size.

[0113] This staged control strategy can dynamically balance the nucleation and growth behavior at different stages of the reaction, and cooperatively control the particle size distribution, morphology sphericity and particle structure of the precursor, so as to prepare small particle size ternary precursors with concentrated particle size, high sphericity, D 50 stable secondary particles with target range.

[0114] In addition, this strategy also has a positive effect on batch consistency and the robustness of the scaling process, which is beneficial to the stable batch preparation under industrial conditions.

[0115] It is worth noting that in the prior art, as the particle size of the ternary precursor is reduced to below 3 μm, especially in the system with Ni content ≥ 90%, the particle nucleation rate and crystallization rate are significantly increased, which often leads to serious particle agglomeration, poor sphericity, and difficulty in realizing uniform particle distribution and compact structure.

[0116] And by using the multi-stage metal salt and alkali solution feeding strategy in this embodiment, combined with the dynamic control of pH during the reaction process, the separation and control of nucleation and growth are effectively realized, and the premature aggregation of primary particles is inhibited, thereby cooperatively improving the sphericity and dispersity of secondary particles. This control method shows significant advantages in controlling the morphology consistency of small particle size precursors and improving batch stability, and is especially suitable for applications such as solid-state batteries that require higher particle morphology, and has good industrial promotion prospects.

[0117] In some embodiments, the reaction process of the reaction of adjusting pH and alkalinity by the alkali solution can be divided into the following two stages: (1) In the reaction process of the reaction of adjusting pH and alkalinity by the alkali solution, nitrogen is passed in from 0 hours to m hours; (2) From m hours to n hours, a mixture of nitrogen and air is passed in. wherein n > m, and 12≥m≥2.

[0118] In the first m hours, nitrogen is introduced to form a relatively inert reaction environment, effectively inhibiting the oxidation reaction that may occur during the reaction process, preventing the oxidation of metal ions (especially low valence nickel ions) to high valence under alkaline conditions by oxygen in the air, thereby maintaining the valence stability of metal ions in the reaction system, and helping to obtain a precursor particle with uniform composition and stable structure.

[0119] From the mth hour to the nth hour, a mixture of nitrogen and air is introduced to gradually introduce a small amount of oxygen, moderately adjust the redox environment of the reaction system, and control the microstructure of the final precursor, such as adjusting the crystal defects, surface state, or trace impurity content, to provide a suitable precursor basis for subsequent generation of positive electrode materials with target performance. Wherein n is the time when the reaction is actually complete or is pre-judged, observed, or indicated by indicators.

[0120] Through this dynamic atmosphere regulation process, more precise control of the precipitation reaction process can be achieved, which is beneficial to improve the particle morphology, distribution uniformity, and product batch stability, and is particularly suitable for industrial scale preparation process of high-Ni ternary material precursor. This scheme avoids the composition segregation or particle size unevenness problem caused by the whole process of air introduction, and also has certain adjustment flexibility and economy compared to the whole process of nitrogen introduction.

[0121] In some embodiments, after the complexation-coprecipitation reaction, at least one of aging, washing, drying, and sieving is further included.

[0122] The above aging treatment can promote the further development and transformation of the precursor crystal structure without introducing additional impurities or structural damage, improve the crystallinity and structural stability of the particles, and is beneficial to improve the thermal stability and electrochemical performance of the material.

[0123] The washing step is used to effectively remove impurity ions and byproduct residues (such as Na + , SO4 2- , etc.) on the surface of the precursor particles, avoiding their adverse effects on the subsequent sintering process and material electrical performance.

[0124] Drying treatment helps to remove free water and part of the crystal water, stabilize the particle morphology, avoid agglomeration, and facilitate subsequent packaging, transportation, and storage. In addition, appropriate drying temperature and time control also helps to maintain the structural integrity and sphericity of the particles.

[0125] The above screening operation can remove agglomerated or abnormal particle size particles, optimize the particle size distribution, make the product particle size more uniform, thereby further improving the filling property and the compaction density of the material, and improving the uniformity and coating performance of subsequent electrode preparation.

[0126] In summary, the method enhances the comprehensive performance of the precursor product by performing at least one post-treatment step on the product after the co-precipitation reaction, thereby providing a good foundation for the preparation of high-performance positive electrode materials.

[0127] In the embodiments of the present application, a positive electrode material is provided, which is prepared based on the small particle size ternary precursor according to any one of the preceding embodiments.

[0128] In the field of lithium ion battery manufacturing, the preparation of positive electrode materials usually includes a high-temperature solid-phase sintering process, i.e., mixing the ternary precursor with a lithium source (such as lithium carbonate, lithium hydroxide) in a certain proportion and then calcining to make the precursor react with lithium to form a lithiated positive electrode material (such as LiNi x Co y Mn z O2). The precursor in the embodiments of the present application has good foundations in stoichiometry and morphology control, which facilitates uniform mixing and sufficient lithiation reaction.

[0129] The spherical or spherical-like structure and the relatively narrow particle size distribution of the precursor are beneficial to forming a dense and uniform lithium layered oxide crystal structure during the lithiation process. Such a structure helps to improve the compaction density and electron / lithium ion transport efficiency of the positive electrode material. In addition, good particle flowability enables the positive electrode material to have excellent processing performance in subsequent electrode sheet preparation (such as slurry preparation, coating, sheet pressing, etc.) links, which is beneficial to industrial application.

[0130] In the embodiments of the present application, a positive electrode sheet is provided, which comprises the positive electrode material according to the preceding embodiments.

[0131] The positive electrode sheet provided in the embodiments of the present application comprises the positive electrode material prepared from the small particle size ternary precursor described above. The positive electrode material can be lithiated after high-temperature solid-phase reaction to form a LiNi x Co y Mn zThe O2 material is mixed with a conductive agent, a binder and a current collector to form a positive electrode sheet. The conductive agent can be acetylene black, conductive carbon black or carbon nanotubes, etc. to enhance the electron conduction performance; the binder can be polyvinylidene fluoride (PVDF) or a water-based system such as CMC / SBR to improve the binding force between the particles and the current collector; and the current collector is preferably an aluminum foil. Through processes such as slurry coating, drying and rolling, a positive electrode sheet with a compact structure and high compaction density can be obtained, which has excellent consistency and processability, and is suitable for cylindrical, square or soft-pack type lithium ion batteries.

[0132] In the embodiments of the present application, a battery is provided, which comprises the positive electrode sheet as described in the foregoing embodiments.

[0133] The battery provided in the embodiments comprises the positive electrode sheet as described above, wherein the positive electrode sheet comprises a positive electrode material prepared based on a small-particle-size ternary precursor with high sphericity and uniform particle size distribution. The battery can further comprise, but is not limited to, a negative electrode sheet, an electrolyte and a separator, etc., and is packaged in a battery shell in a stacked or rolled structure. By using the high-nickel ternary positive electrode material, the battery has high energy density, excellent rate performance and good cycle stability.

[0134] In the embodiments of the present application, an electrical equipment is provided, which comprises the battery as described in the foregoing embodiments.

[0135] The electrical equipment described above comprises the battery as described above, wherein the battery can use a positive electrode material prepared based on a high-nickel ternary precursor, and has high energy density, excellent rate performance and cycle life.

[0136] The electrical equipment can provide efficient and stable energy output for various electric power driving systems, and specific applications can include, but are not limited to, new energy vehicles (such as electric vehicles, plug-in hybrid electric vehicles), consumer electronic products (such as smart phones, notebook computers, tablet computers), portable energy storage devices, unmanned aerial vehicles, electric tools, smart home systems and energy storage power stations, etc. With the performance advantages of the battery, the electrical equipment has significant improvement in service life, safety and endurance.

[0137] The present application will be further described in the following specific examples, but it should be understood that these examples are only used for more detailed description, and should not be understood as limiting the present application in any form.

[0138] Table 1, Comparison of key parameters in examples and comparative examples (I)

[0139] The unit of reaction temperature in Table 1 is ℃.

[0140] Table 2, Comparison of key parameters in examples and comparative examples (II)

[0141] x, y, z in Table 1 represent the molar ratio of nickel (Ni), cobalt (Co), and manganese (Mn), respectively; the percentage before air in the gas row in Table 1 represents the percentage of air flow relative to the nitrogen flow; m represents the time point of cutting off the gas (m gas) from the 0 hour time point, for example, if m = 2, the nitrogen is passed in from the 0 hour to the 2 hour; m gas represents the gas passed in from the 0 hour to the m hour; n gas represents the gas passed in from the m hour to the n hour. In Comparative Examples 1-3, the corresponding gas in the table is continuously passed in throughout the stage.

[0142] In Table 1 and Table 2, TD, BET, and sphericity represent the TD, BET, and sphericity of the final product, respectively; molar ratio represents the molar ratio of metal ions; volume represents the volume of the reaction kettle; subsequent stage represents the pH and flow rate of the subsequent stage; D 50 D represents the D 50 .

[0143] Example 1 In this example, a small particle size ternary precursor is prepared.

[0144] Preparation method (the specific parameters can be referred to Table 1 and Table 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 92:6:2, and the total molar concentration of nickel, cobalt, and manganese metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; a 6.7 mol / L ammonia solution is prepared; (2) A 100 L volume of reaction kettle is added with pure water, sodium hydroxide solution, and ammonia solution as the bottom liquid, the linear speed of the stirring speed is adjusted to 6.10 m / s, the volume of pure water is 40 L, the temperature of the reaction kettle is controlled at 45°C, the pH value is controlled at 11.63 by sodium hydroxide solution, and nitrogen is passed into the reaction kettle at the same time for 2 hours, the nitrogen flow rate is 8 L / min, and the reaction kettle bottom liquid is prepared; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor by a peristaltic pump, and the temperature is maintained at 45°C during the reaction. In the first stage (0 min~20 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 30 mL / min and the alkali at a flow rate of 13 mL / min, and maintaining the pH of the reaction system at 11.60~11.70, and the nucleation reaction time is 20 min; in the second stage (20 min~12 h), the pH is slowly reduced to 11.40~11.50 by reducing the alkali flow rate, and maintained for 12 h; in the third stage (12 h~24 h), the metal salt flow rate is adjusted to 110 mL / min, and the pH in the reactor is maintained at 11.00~11.30 by adjusting the alkali flow rate; in the fourth stage (24 h~end), the metal salt flow rate is adjusted to 160 mL / min after 24 h, and the pH in the reactor is maintained at 10.60~10.80 by adjusting the alkali flow rate. After the precursor particle size D 50 The reaction is stopped when the particle size reaches 1.90 μm, and the entire synthesis time is 76 h, and the solid content in the tank is 468 g / L. In the first 6 h in the reactor, nitrogen gas is introduced, and after 6 h, a mixture of nitrogen gas and air is introduced, the air flow rate is 5% of the nitrogen flow rate, and the ammonium ion concentration (alkalinity) in the reactor is controlled at 2 g / L.

[0145] (4) The slurry prepared in step (3) is aged, washed, dried, and sieved to obtain Ni 0.92 Co 0.06 Mn 0.02 (OH)2precursor product.

[0146] Example 2 In this example, a small-particle-size ternary precursor is prepared.

[0147] Preparation method (the specific parameters can be referred to Tables 1 and 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 92:6:2, and the total molar concentration of the three metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; and a 6.7 mol / L ammonia solution is prepared; (2) Pure water, a sodium hydroxide solution, and an ammonia solution are added to a 100 L volume reactor as a bottom liquid, the linear velocity of the stirring speed is adjusted to 6.50 m / s, the volume of the pure water is 30 L, the temperature of the reactor is controlled at 45°C, the pH value is controlled at 11.46 by the sodium hydroxide solution, and nitrogen gas is introduced into the reactor for 2 h at a flow rate of 15 L / min, and the reactor bottom liquid is prepared; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor through a peristaltic pump, and the temperature is maintained at 45°C during the reaction. In the first stage (0 min~10 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 27 mL / min and the alkali at a flow rate of 11 mL / min, and maintaining the pH of the reaction system at 11.30~11.40, and the nucleation reaction time is 10 min; in the second stage (10 min~12 h), the alkali flow rate is slowly reduced to reduce the pH to 11.20~11.30, and maintained for 12 h; in the third stage (12 h~18 h), the metal salt flow rate is adjusted to 80 mL / min, and the alkali flow rate is adjusted to control the pH in the reactor to be maintained at 9.90~10.90; in the fourth stage (18 h~end), the metal salt flow rate is adjusted to 160 mL / min, and the alkali flow rate is adjusted to control the pH in the reactor to be maintained at 9.70~9.90. Nitrogen is introduced into the reactor for the first 12 hours, and then a mixture of nitrogen and air is introduced, with the air flow rate being 10% of the nitrogen flow rate, the ammonium ion concentration in the reactor is controlled to be 2 g / L, and the entire synthesis time is 64 hours, and the solid content in the tank after stopping is 500 g / L.

[0148] (4) After the reaction product is D 50 After reaching 2.8 μm, the next stage is entered, and the prepared slurry is aged, washed, dried, and sieved to obtain Ni 0.92 Co 0.06 Mn 0.02 (OH)2 precursor product.

[0149] Example 3 In this example, a small-particle-size ternary precursor is prepared.

[0150] Preparation method (the specific parameters can be referred to Tables 1 and 2): (1) A mixed salt solution containing nickel sulfate and cobalt sulfate is prepared according to the molar ratio of nickel metal ions to cobalt metal ions of 98:2, and the total molar concentration of nickel and cobalt metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; and a 6.7 mol / L ammonia solution is prepared; (2) A 300 L volume of reactor is added with pure water, sodium hydroxide solution and ammonia solution as the bottom liquid, the linear velocity of the stirring speed is adjusted to 7.70 m / s, the volume of pure water is 100 L, the temperature of the reactor is controlled to be 45°C, the pH value is controlled by the sodium hydroxide solution to be 11.40, no gas is introduced into the reactor, and the reactor bottom liquid is prepared; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor by a peristaltic pump, and the temperature is maintained at 45°C during the reaction. In the first stage (0 min~15 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 80 mL / min and the alkali at a flow rate of 33 mL / min, and maintaining the pH of the reaction system at 11.35~11.40, and the nucleation reaction time is 15 min; in the second stage (15 min~12 h), the alkali flow rate is slowly reduced to reduce the pH to 11.10~11.20, and maintained for 12 h; in the third stage (12 h~18 h), the metal salt flow rate is adjusted to 160 mL / min, and the pH in the reactor is maintained at 10.10~11.00 by adjusting the alkali flow rate; in the fourth stage (18 h~24 h), the metal salt flow rate is adjusted to 320 mL / min, and the pH in the reactor is maintained at 9.90~10.00 by adjusting the alkali flow rate; in the fifth stage (24 h~end), the metal salt flow rate is adjusted to 600 mL / min, and the pH in the reactor is maintained at 9.60~9.70 by adjusting the alkali flow rate. Nitrogen is introduced into the reactor for the first 4 h, and then a mixture of nitrogen and air is introduced, with the air flow rate being 12% of the nitrogen flow rate, and the ammonium ion concentration in the reactor is controlled at 2 g / L, and the entire synthesis time is 38 h, and the solid content in the tank after stopping is 498 g / L.

[0151] (4) After the reaction product is D 50 After reaching 2.2 pm, the next stage is entered, and the prepared slurry is aged, washed, dried, and sieved to obtain Ni 0.98 Co 0.02 (OH)2 precursor product.

[0152] Example 4 In this example, a small-particle-size ternary precursor is prepared.

[0153] Preparation method (the specific parameters can be referred to Tables 1 and 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 92:6:2, and the total molar concentration of the three metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; and a 6.7 mol / L ammonia solution is prepared; (2) Pure water, a sodium hydroxide solution, and an ammonia solution are added to a 300 L volume reactor as a bottom liquid, the linear velocity of the stirring speed is adjusted to 7.21 m / s, the volume of the pure water is 120 L, the temperature of the reactor is controlled at 45°C, the pH value is controlled at 11.38 by the sodium hydroxide solution, and nitrogen is introduced into the reactor for 2 h at a flow rate of 8 L / min, and the reactor bottom liquid is prepared; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor by a peristaltic pump, and the temperature is maintained at 45°C during the reaction. In the first stage (0 min~20 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 90 mL / min and the alkali at a flow rate of 37 mL / min, and maintaining the pH of the reaction system at 11.30~11.40, and the nucleation reaction time is 20 min; in the second stage (20 min~12 h), the pH is slowly reduced to 11.10~11.30 by reducing the alkali flow rate, and maintained for 12 h; in the third stage (12 h~24 h), the metal salt flow rate is adjusted to 180 mL / min, and the pH is maintained at 10.80~11.00 by adjusting the alkali flow rate; in the fourth stage (24 h~end), the metal salt flow rate is adjusted to 330 mL / min after 24 h, and the pH is maintained at 10.50~10.70 by adjusting the alkali flow rate. The reaction is stopped when the precursor particle size D50 reaches 2.30 μm, and the entire synthesis time is 48 h, and the solid content in the tank is 300 g / L. Nitrogen is introduced into the reactor for the first 2 h, and then a mixture of nitrogen and air is introduced, and the air flow rate is 15% of the nitrogen flow rate, and the ammonium ion concentration (alkalinity) in the reactor is controlled at 2 g / L.

[0154] (4) The slurry prepared in step (3) is aged, washed, dried, and sieved to obtain a Ni 0.92 Co 0.06 Mn 0.02 (OH)2 precursor product.

[0155] Comparative Example 1 In this example, a ternary precursor is prepared.

[0156] Preparation method (the specific parameters can be referred to Tables 1 and 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 95:4:1, and the total molar concentration of the three metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; and a 6.7 mol / L ammonia solution is prepared; (2) A 300 L volume reactor is added with pure water, a sodium hydroxide solution, and an ammonia solution as a bottom liquid, the linear velocity of the stirring speed is adjusted to 5.99 m / s, the volume of the pure water is 100 L, the temperature of the reactor is controlled at 50°C, the pH value is controlled at 11.55 by the sodium hydroxide solution, and nitrogen is introduced into the reactor for 2 h at a flow rate of 15 L / min, and the reactor bottom liquid is prepared; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor through a peristaltic pump, and the temperature is maintained at 50°C during the reaction. In the first stage (0 min~20 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 160 mL / min and the alkali at a flow rate of 66 mL / min, and maintaining the pH of the reaction system at 11.50~11.55, and the nucleation reaction time is 20 min; in the second stage (20 min~12 h), the alkali flow rate is slowly reduced to reduce the pH to 11.15~11.30, and maintained for 12 h; in the third stage (12 h~18 h), the metal salt flow rate is adjusted to 240 mL / min, and the alkali flow rate is adjusted to control the pH in the reactor to be maintained at 11.00~11.10; in the fourth stage (18 h~24 h), the metal salt flow rate is adjusted to 320 mL / min, and the alkali flow rate is adjusted to control the pH in the reactor to be maintained at 10.10~10.30. In the fifth stage (24 h~end), the metal salt flow rate is adjusted to 600 mL / min, and the alkali flow rate is adjusted to control the pH in the reactor to be maintained at 9.60~9.70. During the reaction, nitrogen is continuously introduced into the reactor for protection, the ammonium ion concentration in the reactor is controlled to be 2 g / L, and the entire synthesis time is 33 h, and the solid content in the tank after stopping is 310 g / L.

[0157] (4) After the D 50 After reaching 2.0 μm, the next stage is entered, and the prepared slurry is aged, washed, dried, and sieved to obtain Ni 0.95 Co 0.04 Mn 0.01 (OH)2 precursor product.

[0158] Comparative Example 2 In this example, a preparation of a ternary precursor is carried out.

[0159] Preparation method (the specific parameters can refer to Table 1 and Table 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 92:6:2, and the total molar concentration of the three metal ions in the mixed salt solution is 2 mol / L; a 10 mol / L sodium hydroxide solution is prepared; and a 6.7 mol / L ammonia solution is prepared; (2) A 300 L volume of a reactor is added with pure water, a sodium hydroxide solution, and an ammonia solution as a bottom liquid, the linear speed of the stirring speed is adjusted to 7.15 m / s, the volume of the pure water is 198 L, the temperature of the reactor is controlled to be 55°C, the pH value is controlled to be 11.21 by the sodium hydroxide solution, and air is introduced into the reactor at a flow rate of 3 L / min for 2 hours to prepare the bottom liquid of the reactor; (3) After the reactor system is stable, the metal salt solution, the alkali solution, and the ammonia solution are simultaneously injected into the reactor through a peristaltic pump. The temperature is maintained at 55°C during the reaction, and the air flow rate is 3 L / min. In the first stage (0-25 min), the nucleation reaction is carried out by feeding the metal salt at a flow rate of 240 mL / min and the alkali at a flow rate of 99 mL / min, and maintaining the pH of the reaction system at 11.21-11.30. The nucleation reaction time is 25 min. In the second stage (25 min-3 h), the alkali flow is closed to slowly reduce the pH to 10.80-10.90, and maintained for 3 h. In the third stage (3 h-end), the air flow is adjusted to 4 L / min, the metal salt flow is adjusted to 360 mL / min, and the alkali flow is adjusted to control the pH in the reactor to be maintained at 10.20-10.30. During the reaction, air is continuously introduced into the reactor to slowly reduce the ammonium ion concentration in the reactor from 7 g / L to 3 g / L. The entire synthesis time is 18 h, and the tank contains 140 g / L of solid.

[0160] (4) After the reaction product is D 50 After reaching 2.8 μm, the prepared slurry is aged, washed, dried, and sieved to obtain Ni 0.92 Co 0.06 Mn 0.02 (OH)2 precursor product.

[0161] Comparative Example 3 In this example, a ternary precursor is prepared.

[0162] Preparation method (the specific parameters can be referred to Tables 1 and 2): (1) A mixed salt solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared according to the molar ratio of nickel, cobalt, and manganese metal ions of 96:3:1. The total molar concentration of the three metal ions in the mixed salt solution is 2 mol / L. A 10 mol / L sodium hydroxide solution is prepared. A 6.7 mol / L ammonia solution is prepared. (2) Pure water, sodium hydroxide solution, and ammonia solution are added to a 300 L volume reactor as a bottom liquid. The linear speed of the stirring speed is adjusted to 7.05 m / s. The volume of pure water is 100 L. The temperature of the reactor is controlled at 55°C. The pH value is controlled at 11.40 by using sodium hydroxide solution. Nitrogen is introduced into the reactor for 2 hours at a flow rate of 15 L / min. The bottom liquid of the reactor is prepared. (3) After the reaction vessel system stabilizes, the metal salt solution, alkali solution, and ammonia solution are simultaneously injected into the reaction vessel using a peristaltic pump. The temperature is maintained at 55℃ and the nitrogen flow rate is 15L / min during the reaction. First stage (0 minutes to 20 minutes): The nucleation reaction is carried out by feeding metal salt at a flow rate of 360mL / min and alkali at a flow rate of 150mL / min, and maintaining the pH of the reaction system between 11.40 and 11.50 for 20 minutes. Second stage (20 minutes to 4 hours): The alkali flow rate is turned off to allow the pH value to slowly decrease to between 11.00 and 10.80 and maintain this for 4 hours. Third stage (4 hours to end): The metal salt flow rate is adjusted to 480mL / min, and the alkali flow rate is adjusted to maintain the pH in the vessel between 10.50 and 10.60. Nitrogen is continuously introduced into the reaction vessel for protection during the reaction process, and the ammonium ion concentration in the vessel is controlled at 5g / L. The entire synthesis time is 24 hours, and the solid content at the end of the reaction is 175g / L.

[0163] (4) D of the product to be reacted 50 After reaching 1.8 μm, the next stage begins. The prepared slurry is aged, washed, dried, and sieved to obtain Ni. 0.96 Co 0.03 Mn 0.01 (OH)2 precursor products.

[0164] Test experiment: 1. Testing method: (1) Precursor properties and performance tests: The particle tap density (TD), particle specific surface area (BET) and particle sphericity of the products prepared in the examples and comparative examples were tested respectively.

[0165] (2) Battery performance test: To evaluate the electrochemical performance of the prepared small-particle-size ternary precursor, the following steps were used to assemble the precursor into a coin cell and perform charge-discharge cycle characteristics tests: A. Preparation of cathode material: The precursor samples prepared in the examples and comparative examples were taken and mixed with lithium hydroxide (LiOH·H2O) at a molar ratio of 1:1.05. The mixture was placed in a muffle furnace and sintered at 760°C for 12 hours (oxygen atmosphere). After cooling, the cathode material was obtained.

[0166] B. Electrode preparation: The obtained positive electrode material is mixed with conductive agent (acetylene black) and binder (PVDF) at a mass ratio of 90:5:5. An appropriate amount of NMP solvent is added to make a uniform slurry, which is uniformly coated on aluminum foil current collector. After drying and rolling, it is punched into round sheets as positive electrode sheets.

[0167] C. Button cell assembly: In an argon atmosphere glove box, using the above-mentioned positive electrode as the positive electrode and the lithium sheet as the negative electrode, a polypropylene separator (Celgard2400) and liquid electrolyte (1MLiPF6 / EC+DMC=1:1, volume ratio) are used to assemble CR2032 button cells.

[0168] At 25°C, the charge-discharge cycle characteristics of the coin cells prepared in each experimental group were tested using a blue electric test cabinet. Charge and discharge were performed at a rate of 0.1C within a voltage range of 2.8V to 4.3V. The charge-discharge capacity after the first cycle was recorded.

[0169] 2. Test Results: Table 3. Test metrics and results for the examples and comparative examples.

[0170] The battery performance of each embodiment and comparative example is shown in Table 3.

[0171] Table 4. Electrochemical performance of each example and comparative example

[0172] 3. Analysis: Refer to the data in Tables 3 and 4, and Figures 1-9 The microstructure and particle size measurement data are as follows.

[0173] (1) As can be seen from Table 3, the tap density (TD) of the ternary precursor products obtained in Examples 1 to 4 of this application are 1.65, 1.41, 1.20, and 1.51 g / cm³, respectively. 3 The coverage range is 1.20~1.65g / cm³. 3 Example 1 exhibited the highest tap density, indicating the most compact particle packing and regular shape. This contributes to increasing the compaction density of the battery electrode, thereby increasing the battery's energy density. In contrast, the tap densities of Comparative Examples 1–3 were 1.32, 1.51, and 1.54 g / cm³, respectively. 3 Although some values ​​were close to the lower limit of the examples, the overall levels were below the optimum, especially Comparative Example 1 (1.32 g / cm³). 3 The density of Comparative Example 3 is significantly lower than expected. The tap density of Comparative Example 3 is 1.54 g / cm³. 3 Although the sphericity is relatively high, the sphericity is low, indicating that the particle shape is not regular enough, which may affect the performance and consistency of the battery.

[0174] Such differences are due to the difference in process path. In the examples, a synergistic control strategy is adopted, such as low-speed nucleation feeding (30 mL / min), precise pH control at 11.60-11.70, and staged atmosphere regulation (such as nitrogen first and then trace oxygen), which significantly improves the grain density and regularity of the morphology. In Comparative Example 1, high flow rate feeding and single nitrogen atmosphere throughout are used, resulting in uneven crystal growth and intensified agglomeration.

[0175] (2) The specific surface areas of Examples 1, 2, 3 and 4 are 20.88 m 2 / g, 20.05 m 2 / g, 32.64 m 2 / g and 26.96 m 2 / g, respectively. The specific surface area of Example 3 is the highest, indicating that it has the most active sites on the particle surface and a rich pore structure, which helps to improve the rate performance and rapid charge-discharge capability of the battery. The specific surface areas of Comparative Example 1 and Comparative Example 3 are 25.67 m 2 / g and 24.42 m 2 / g, respectively. Although the specific surface areas of Comparative Example 1 and Comparative Example 3 are relatively high, the sphericity is low, indicating that the particle shape is not regular enough, which may affect the charge-discharge efficiency and cycle stability of the battery.

[0176] (2) Sphericity is an important indicator of the regularity of particle shape, and a value close to 1 indicates that the particle shape is closer to a perfect sphere. The sphericities of Examples 1, 2, 3 and 4 are 0.91, 0.92, 0.90 and 0.90, respectively, while the sphericities of Comparative Examples 1, 2 and 3 are 0.81, 0.80 and 0.85, respectively. The sphericities of the examples are all above 0.90, indicating that the particle shape is close to a perfect sphere, with good flowability and packing efficiency, making it suitable for the preparation of battery electrodes. In contrast, the sphericities of Comparative Examples 1, 2 and 3 are low, indicating that the particle shape is not regular enough, which may cause agglomeration, affecting the performance and consistency of the battery, and possibly leading to reduced efficiency and shortened cycle life during the charge-discharge process. From the above experimental results, it can be seen that the examples successfully solve the problems of easy agglomeration and low sphericity of high-nickel materials at small particle size, significantly improving the overall performance of the material.

[0177] Compared with the comparative examples, the examples of the present application effectively improve the sphericity through measures such as segmented feeding, precise pH control, stirring and atmosphere regulation, and even in the case of a high specific surface area (such as 32.64 m2 / g in Example 3), the morphology structure is still good, and the overall performance advantage is significant.

[0178] (3) The embodiments adopt low-temperature and low-ammonium ion concentration reaction conditions, and optimize the reaction kinetics by adjusting the metal salt flow and pH value in stages, so that the growth process of the particles is more controllable. In addition, the introduction of mixed gas of nitrogen and air further suppresses the agglomeration of particles, realizes the synergistic optimization of specific surface area and sphericity, and significantly improves the structural uniformity, packing and electrochemical stability of the material, which reflects the systematic advantages of the technical route. The comparative examples use high temperature, high flow rate feeding and single nitrogen atmosphere throughout the process, resulting in uneven crystal growth and severe agglomeration.

[0179] (4) Table 4 shows that the first discharge capacities of Examples 1-4 are 230.01, 222.76, 229.18 and 215.22 mAh / g, respectively, which are higher than those of Comparative Examples 1-3 (209.17, 212.92 and 189.59 mAh / g, respectively). The capacity retention rates of Examples 1-4 after 50 cycles are 94.1%, 92.8%, 91.2% and 90.3%, respectively, which are significantly higher than those of Comparative Examples 1-3 (88.6%, 89.5% and 87.4%, respectively). This indicates that the small particle size ternary precursor in the embodiments has better cycle stability. For example, in Example 1, on the basis of having a higher sphericity (0.91) and tap density (1.65 g / cm 3 ), a discharge capacity of 230.01 mAh / g and a cycle retention rate of 94.1% are achieved, verifying the comprehensive performance advantages of the technical solution.

[0180] This advantage is mainly due to the optimized preparation process in the embodiments, such as controlling the metal salt flow and pH value in stages, and introducing nitrogen or mixed gas of nitrogen and air during the reaction process, which effectively suppresses particle agglomeration and improves particle sphericity and dispersity. High-sphericity particles have better flowability and packing efficiency during electrode preparation, and can form a more compact electrode structure, thereby improving the transmission efficiency of lithium ions and the uniformity of electrochemical reactions. In contrast, due to particle agglomeration and low sphericity, the electrode structure of the comparative examples is not compact enough, the transmission of lithium ions is hindered, and the cycle stability is poor. Therefore, the optimized process of the embodiments significantly improves the cycle performance of the material, providing important support for the preparation of high-performance lithium battery cathode materials.

[0181] In summary, the embodiments of the present application improve the comprehensive performance of the material in terms of structure morphology, electrochemical reaction uniformity and cycle structure stability through core process innovations such as segmented metal salt feeding, dynamic pH control and atmosphere switching adjustment, which are significantly superior to the comparative examples that do not use these process optimization strategies, and have obvious technical progress.

[0182] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A small-particle-size ternary precursor, characterized in that, The chemical formula of the small-particle-size ternary precursor is Ni. x Co y Mn z (OH)2; Where 0.92≤x≤0.98, 0.02≤y≤0.06, 0≤z≤0.02, and x+y+z=1; The small-particle-size ternary precursor has a spherical or near-spherical particle shape, with a sphericity of not less than 0.

89.

2. The small-particle-size ternary precursor as described in claim 1, characterized in that, The small-particle-size ternary precursor is a secondary particle formed by the spontaneous aggregation of primary particles. Preferably, the secondary particles have at least one of the following characteristics: A. Particle size D 50 The range is 1.5μm to 2.8μm; B. Particle size distribution is 0.90 < (D 90 -D 10 ) / D 50 <1.2; C. Specific surface area is 20m² 2 / g~35m 2 / g; D. Tap density is 1.0 g / cm³ 3 ~1.8g / cm 3 .

3. A method for preparing a small-particle-size ternary precursor as described in any one of claims 1-2, characterized in that, include: A mixed solution of metal salts containing nickel, cobalt, and manganese sources, an alkaline solution, and an ammonia solution are introduced into the reaction system and mixed. Under reaction conditions of 40℃~60℃, pH 9.8~11.8, and alkalinity of 1g / L~5g / L, the small-particle-size ternary precursor is generated through a complexation-coprecipitation reaction. Preferably, the nickel source includes one or more of nickel sulfate, nickel nitrate, and nickel chloride; and / or, Preferably, the cobalt source includes one or more of cobalt sulfate, cobalt nitrate, and cobalt chloride; Preferably, the manganese source includes one or more of manganese sulfate, manganese nitrate, and manganese chloride; Preferably, the total molar concentration of nickel, cobalt, and manganese ions in the metal salt mixed solution is 1 mol / L to 3 mol / L; Preferably, the alkaline solution comprises sodium hydroxide solution and / or potassium hydroxide solution; Preferably, the concentration of the sodium hydroxide solution and / or potassium hydroxide solution is 8 mol / L to 12 mol / L; Preferably, the concentration of the ammonia solution is 5 mol / L to 8 mol / L; Preferably, the complexation-coprecipitation reaction includes: The alkaline solution and the ammonia solution are stirred under a first protective atmosphere to prepare a reaction base solution. The metal salt mixture is introduced into the reaction substrate in stages, and the pH and alkalinity are adjusted using the alkaline solution to carry out the staged reaction, thereby generating the small-particle-size ternary precursor.

4. The method for preparing the small-particle-size ternary precursor as described in claim 3, characterized in that, The preparation of the reaction substrate has at least one of the following characteristics: A. The first protective atmosphere is nitrogen, or a mixture of nitrogen and air; B. The linear velocity of the stirring process is 4m / s to 9m / s; C. The temperature during the stirring process is controlled at 40℃~60℃; D. The pH during the stirring process is controlled at 11.2~11.

9.

5. The method for preparing the small-particle-size ternary precursor as described in claim 3, characterized in that, The phased reaction, which utilizes the alkaline solution to adjust pH and alkalinity, includes: In the first stage, the metal salt mixed solution is introduced into the reaction substrate at a flow rate of 20 mL / min to 50 mL / min, and the alkaline solution is introduced into the reaction system at a flow rate of 10 mL / min to 15 mL / min to carry out the nucleation reaction, with the pH controlled at 11.60 to 11.70 and the reaction time at 10 to 30 minutes. In the second stage, the flow rate of the alkaline solution is reduced, and the pH is controlled at 11.40~11.50 for 8 to 16 hours. In the third stage, the flow rate of the metal salt mixed solution is adjusted to 100 mL / min to 120 mL / min, and the pH is controlled at 11.00 to 11.30 for 8 to 16 hours. In the fourth stage, the flow rate of the metal salt mixed solution is increased to 150 mL / min to 180 mL / min, the pH of the reaction system is controlled between 10.60 and 10.80, and this is maintained for 8 to 16 hours until the reaction product reaches D0. 50 The thickness reaches 1.5μm~2.8μm.

6. The method for preparing the small-particle-size ternary precursor as described in claim 5, characterized in that, During the reaction process in which the pH and alkalinity are adjusted by the alkaline solution in stages, nitrogen gas is introduced from hour 0 to hour m; and / or, a mixture of nitrogen and air is introduced from hour m to hour n. Where n > m, and 12 ≥ m ≥ 2.

7. A positive electrode material, characterized in that, The cathode material is prepared based on the small-particle-size ternary precursor as described in any one of claims 1-2.

8. A positive electrode plate, characterized in that, Including the cathode material as described in claim 7.

9. A battery, characterized in that, Includes the positive electrode as described in claim 8.

10. An electrical-related device, characterized in that, Includes the battery as described in claim 9.

Images