High-power positive electrode material precursor as well as preparation method and application thereof

Abstract

The invention provides a high-power positive electrode material precursor and a preparation method and application thereof, the high-power positive electrode material precursor is a ternary precursor, the ternary precursor comprises an inner core and a shell, the inner core is porous, the shell is relatively compact, and the oil absorption of the precursor is 40-85mL / 100g. The provided precursor is loose and porous in inner core, relatively compact in shell and relatively high in oil absorption amount, a uniform hole structure is formed in the positive electrode material after the provided precursor is sintered, electrolyte infiltration can be improved, rate capability is improved, capacity exertion is facilitated, a compact shell layer is formed outside the positive electrode material, particle strength of particles is improved, and the performance of the positive electrode material is improved. Collapse is not easy to occur in the circulation process, and the circulation performance of the high-power positive electrode material is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery materials, and particularly relates to a high-power positive electrode material precursor and a preparation method and application thereof. BACKGROUND

[0002] For HEV batteries, frequent charging and discharging in a short time are required, and therefore the batteries need to have excellent rate performance and cycle performance. In order to improve ion transmission performance, most of the current HEV positive electrode materials have a large specific surface area and a hollow and porous structure, and in the long cycle process, the positive electrode material may be broken and the cycle impedance may increase.

[0003] Patent CN118598211A discloses a core-shell structure precursor and a preparation method and application thereof. The core-shell structure precursor includes a porous nickel-rich inner core and a manganese-rich or aluminum-containing outer shell coated on the surface of the inner core, and the primary grains constituting the inner core are thin and thin needles, and the primary grains constituting the outer shell are thick and thick blocks. In the process of coprecipitation reaction, a loose and porous structure is manufactured in the inner core by using micro-oxidation to form a core-shell structure, and the positive electrode material prepared by using the precursor can improve the rate performance of the positive electrode material, improve the cycle performance, and improve the safety performance of the material. The deficiency is that in the core-shell structure precursor of the application, the inner core is a nickel-cobalt-manganese hydroxide with high nickel content and low manganese content, and the outer shell is a nickel-manganese hydroxide, a nickel-cobalt-manganese hydroxide or an aluminum-containing nickel-cobalt-aluminum hydroxide with low nickel content and high manganese content. In order to obtain this structure, the stage I reaction is carried out in an inert atmosphere, and then the stage II reaction is carried out in a micro-oxidation atmosphere, after the preset particle size is reached, the reaction solution is switched to carry out the stage III reaction to prepare the outer shell. This process may cause deviation of the transition metal chemical ratio of the precursor when the particle size is controlled to fluctuate, and if the time length of each reaction is controlled, the particle size may not reach the preset target, which is not conducive to large-scale stable mass production.

[0004] Patent CN117509757A controls the specific surface area of a ternary positive electrode material precursor to be 10-20m 2 / g, the median particle size D50 is controlled in 2~5 μm, the primary particle width is controlled in 60~300 nm, and a special structure is provided to improve the capacity and cycle performance of the lithium ion battery. The special structure is that the ternary positive electrode material precursor comprises an inner core part and an outer peripheral part covering at least part of the surface of the inner core part; the inner core part comprises honeycomb-shaped arranged primary particles, and the outer peripheral part comprises radially arranged primary particles. The inner core part is loosely porous and arranged in a honeycomb shape, which is beneficial to the absorption and storage of lithium ions and alleviates the volume expansion in the charging and discharging process; the outer peripheral part is radially arranged, which can shorten the diffusion path of lithium ions in the sintering process, so that the lithium salt is more easily diffused into the inside of the precursor, and the reaction is more sufficient. The two are coordinated, and the distribution of lithium ions in the inside and outside of the ternary positive electrode material precursor is more uniform, which significantly improves the capacity and cycle performance of the positive active material. At the same time, it is also beneficial to ion conduction in the cycle process, and can also improve the rate performance of the battery to a certain extent. The porosity of the inner core part is 10~35%, the porosity of the outer peripheral part is 5~10%, and the porosity of the ternary positive electrode material precursor is 8~18%. The overall porosity of the precursor is not high, and the cross-sectional area of the inner core part with high porosity is too small, so the capacity and rate performance are insufficient. SUMMARY

[0005] The present application aims to solve the above-mentioned problems in the prior art, and aims to provide a high-power positive electrode material precursor and a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: In a first aspect, a high-power positive electrode material precursor is provided. The precursor is a ternary precursor, which comprises an inner core and a shell. The inner core is porous, and the shell is relatively dense. The oil absorption of the precursor is 40~85 mL / 100g.

[0007] Further, the morphology of the inner core of the precursor is a spherical amorphous morphology. The oil absorption of the inner core of the precursor is 80~120 mL / 100g. The particle size D50 of the inner core of the precursor is 2.0 μm~4.0 μm, and the TD is 0.5~0.8 g / cm 3 , and the specific surface area is 50~95 m 2 / g.

[0008] Further, the shell is formed by agglomeration of sheet-shaped primary particles. The thickness of the sheet-shaped primary particles is 60~160 nm.

[0009] Further, the ratio of the diameter of the inner core to the diameter of the precursor is 65~90%. The shell thickness of the shell is 0.25~0.8 μm, and is preferably 0.25~0.6 μm.

[0010] Further, the particle size D50 of the precursor is 2.5-6.5 μm; the tap density of the precursor is 0.8-1.9 g / cm 3 .

[0011] Further, the chemical formula of the precursor is Ni x Co y Mn z (OH)2, wherein 0.3≤x≤0.7, 0≤y≤0.3, 0≤z≤0.5, and x+y+z=1.

[0012] In a second aspect, a preparation method of a high-power positive electrode material precursor is provided, comprising: S1, core preparation: mixed metal salt solution, ammonia water and lye are introduced into the first reactor bottom liquid in parallel, and the reaction is carried out. Overflow is carried out during the reaction. After the particle size is stabilized at the first target particle size D50, the slurry is concentrated and then backflowed into the reactor. The solid content in the reactor is controlled at 201 g / L-450 g / L. After the solid content is stabilized, an oxidizing gas is introduced, and the oxygen content in the reaction atmosphere above the slurry in the reactor is maintained at 5.1-10%. After a period of reaction, the slurry discharged from the overflow port is collected, washed, and solid-liquid separated to obtain a precursor core seed. The metals in the mixed metal salt solution include nickel and at least one selected from cobalt and manganese; S2, shell preparation: the precursor core seed is added to the second reactor bottom liquid, and after stirring, mixed metal salt solution, ammonia water and lye are introduced into the second reactor bottom liquid in parallel to react. After 0.5-1.5 h, the introduction of mixed metal salt solution, ammonia water and lye is stopped. After the temperature is raised, a ripening treatment is carried out. After ripening is completed, mixed metal salt solution, ammonia water and lye are continuously introduced into the second reactor bottom liquid in parallel, and the reaction is continued until the precursor grows to the second target particle size D50.

[0013] In a third aspect, a high-power positive electrode material is provided. The high-power positive electrode material is obtained by sintering a precursor provided in the first aspect or prepared by the preparation method provided in the second aspect with a lithium salt; or by sintering a precursor provided in the first aspect or prepared by the preparation method provided in the second aspect with a lithium salt and a dopant.

[0014] In a fourth aspect, a secondary battery is provided, comprising the high-power positive electrode material provided in the third aspect.

[0015] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: The provided precursor has a loose porous inner core and a relatively dense shell, and a high oil absorption amount. The provided precursor forms a uniform pore structure in the positive electrode material after sintering, which can improve the infiltration of electrolyte, improve the rate performance, help to give the capacity, and form a dense shell outside the positive electrode material, which is beneficial to improve the particle strength of the particles, and is not easy to collapse in the cycle process, and is beneficial to improve the cycle performance of the high-power positive electrode material.

[0016] By optimizing the crystal form, oil absorption amount, particle size, and diameter ratio of the inner core and the precursor of the precursor inner core, the rate performance and cycle performance of the positive electrode material can be further improved.

[0017] The provided preparation method has a simple process, the crystal seed is prepared by a continuous method, the yield is high, the batch stability is good, and batch stable production is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 SEM image of the inner core of the precursor obtained in Example 1.

[0020] Figure 2 XRD image of the inner core of the precursor obtained in Example 1.

[0021] Figure 3 XRD image of the final precursor obtained in Example 1.

[0022] Figure 4 SEM image of the final precursor obtained in Example 1.

[0023] Figure 5 Cross-sectional SEM image of the final precursor obtained in Example 1.

[0024] Figure 6 Cross-sectional SEM image of the final precursor obtained in Example 2.

[0025] Figure 7 Cross-sectional SEM image of the final precursor obtained in Example 3.

[0026] Figure 8 SEM image of the inner core of the precursor obtained in Comparative Example 1.

[0027] Figure 9 SEM image of the inner core of the precursor obtained in Comparative Example 2.

[0028] Figure 10 SEM image of the final precursor obtained in Comparative Example 2.

[0029] Figure 11 SEM image of the final precursor obtained in Comparative Example 3. DETAILED DESCRIPTION

[0030] Some embodiments of the present application provide a high-power cathode material precursor, which is a ternary precursor, the ternary precursor comprising an inner core and an outer shell, the inner core being porous and the outer shell being relatively dense, the oil absorption of the precursor being 40-85 mL / 100 g, such as 40 mL / 100 g, 45 mL / 100 g, 50 mL / 100 g, 55 mL / 100 g, 60 mL / 100 g, 65 mL / 100 g, 70 mL / 100 g, 75 mL / 100 g, 80 mL / 100 g, 85 mL / 100 g, etc. The provided precursor forms a uniform pore structure inside the sintered cathode material, which can improve the infiltration of electrolyte, improve the rate performance, facilitate the capacity development, and forms a dense shell layer outside the cathode material, which is beneficial to improve the particle strength of the particles, and the particles are not prone to collapse during the cycle process, the cycle impedance grows slowly, and it is beneficial to improve the cycle performance of the high-power cathode material.

[0031] In some preferred embodiments, the morphology of the inner core of the precursor is a spherical amorphous morphology, which is beneficial to improve the specific surface area and ion transmission, the XRD diffraction peak intensity is <600, and the (001) half-peak width (i.e. the diffraction peak width of the 001 crystal face) is >0.8°; the oil absorption of the inner core of the precursor is 80-120 mL / 100 g, such as 80 mL / 100 g, 85 mL / 100 g, 90 mL / 100 g, 95 mL / 100 g, 100 mL / 100 g, 105 mL / 100 g, 110 mL / 100 g, 115 mL / 100 g, 120 mL / 100 g, etc., the inner core region has high oil absorption and many pores, and the precursor has high porosity, which is more beneficial to capacity development and rate performance improvement; the particle size D50 of the inner core of the precursor is 2.0 μm-4.0 μm, such as 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, etc.; TD is 0.5-0.8 g / cm 3 , such as 0.5 g / cm 3 , 0.55 g / cm 3 , 0.6 g / cm 3 , 0.65 g / cm 3 , 0.7 g / cm 3 , 0.75 g / cm 3 , 0.8 g / cm 3 , etc.; the specific surface area is 50-95 m 2 / g, such as 50 m 2 / g, 55 m2 / g, 60 m 2 / g, 65 m 2 / g, 70 m 2 / g, 75 m 2 / g, 80 m 2 / g, 85 m 2 / g, 90 m 2 / g, 95 m 2 / g, etc.

[0032] In some preferred embodiments, the shell is formed by agglomeration of flaky primary particles; the thickness of the flaky primary particles is 60-160 nm, such as 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, etc.

[0033] In some preferred embodiments, the ratio of the diameter of the inner core to the diameter of the precursor is 65-90%, such as 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, etc., and a larger proportion of the inner core region is conducive to improving the porosity of the precursor, and thus to improving the capacity and rate performance; the shell thickness of the shell is 0.25-0.8 μm, preferably 0.25-0.6 μm, such as 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, etc., and a thin shell can increase the proportion of the inner core pore region, increase the contact area of the electrolyte and the active material, and improve the ion transport performance.

[0034] In some preferred embodiments, the particle size D50 of the precursor is 2.5-6.5 μm, such as 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, etc., and a particle size that is too small has a too large specific surface area, which is prone to side reactions with the electrolyte, and a particle size that is too large has a too small specific surface area, which reduces ion transport performance; the tap density of the precursor is 0.8-1.9 g / cm 3 , such as 0.8 g / cm 3 , 0.9 g / cm 3 , 1.0 g / cm 3 , 1.1 g / cm 3 , 1.2 g / cm 3 , 1.3 g / cm 3 , 1.4 g / cm 3 , 1.5 g / cm 3 , 1.6 g / cm 3 , 1.7 g / cm 3 , 1.8 g / cm 31.9 g / cm3 3 etc.

[0035] In some preferred embodiments, the precursor has a chemical formula of Ni x Co y Mn z (OH)2, wherein 0.3≤x≤0.7, such as 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, etc., 0≤y≤0.3, such as 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, etc., 0≤z≤0.5, such as 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc., and x+y+z=1.

[0036] Some embodiments of the present application provide a method for preparing a high-power positive electrode material precursor, comprising: S1, core preparation: a mixed metal salt solution, ammonia water and alkali solution are introduced into the first reactor bottom liquid in parallel flow, and the reaction is carried out, and overflow is carried out during the reaction process; after the particle size is stabilized at the first target particle size, the slurry is concentrated and then backflowed into the reactor, and the solid content in the reactor is controlled at 201 g / L~450 g / L (such as 201 g / L, 220 g / L, 250 g / L, 280 g / L, 300 g / L, 320 g / L, 350 g / L, 380 g / L, 400 g / L, 420 g / L, 450 g / L, etc.), and after the solid content is stabilized, an oxidizing gas is introduced, the oxygen content in the reaction atmosphere above the slurry in the reactor is maintained at 5.1~10%, and after a period of reaction, the slurry discharged from the overflow port is collected, the obtained slurry is washed and solid-liquid separated, and a precursor core seed is obtained; the metal in the mixed metal salt solution includes nickel and at least one selected from cobalt and manganese; The morphology and oil absorption of the amorphous precursor of the quasi-spherical shape are adjusted by the solid content in step S1 and the oxygen concentration in the headspace of the reactor. When the solid content is too low, the particles formed by strong oxidation are too fine to be aggregated into blocks, so that the quasi-spherical morphology cannot be obtained, and on the other hand, it is difficult to stably control the particle size; when the solid content is too high, the required air flow increases sharply, and the oxidation effect is poor due to the limitation of fluid mass transfer, so that the amorphous morphology cannot be obtained. When the oxygen concentration in the headspace of the reactor is too low, the oxidation is insufficient, so that the primary particles have a certain crystallinity, and the amorphous morphology cannot be obtained; when the oxygen concentration in the headspace of the reactor is too high, the particles are too fine to form extremely loose aggregates, so that the quasi-spherical morphology cannot be obtained. During the reaction, the slurry in the reactor is pumped to the thickener for concentration and then returned to the reactor, and the solid content in the reactor is controlled at 201 g / L to 450 g / L by adjusting the clear flow of the thickener. It should be noted that the reactor is closed during the co-precipitation reaction, but it is not absolutely completely closed. It is a closed system with controllable interfaces (such as gas inlet, gas outlet, monitoring port), so the oxygen in the reactor will be consumed continuously during the reaction. Therefore, in order to maintain the oxygen concentration in the system at a certain proportion after a period of reaction, it is necessary to introduce an oxidizing gas, which can be air, oxygen or a mixture of the two.

[0037] S2, shell preparation: the precursor core seed is added to the bottom liquid of the second reactor, and after stirring, the mixed metal salt solution, ammonia and alkali are introduced into the second reactor bottom liquid in parallel to react. After 0.5 to 1.5 hours, stop introducing the mixed metal salt solution, ammonia and alkali, increase the temperature and perform aging treatment, and after the aging is completed, continue to introduce the mixed metal salt solution, ammonia and alkali into the second reactor bottom liquid in parallel, and continue to react until the precursor grows to the second target particle size.

[0038] It is worth mentioning that in step S2, before the ripening treatment, the temperature, pH value and ammonia concentration need to be kept within a certain range during the reaction process of feeding the material; after the ripening treatment, the reaction system temperature, pH value and ammonia concentration also need to be kept within a certain range during the continuous growth reaction of feeding the material. In step S2, the purpose of ripening is to disperse the amorphous morphology of the seed crystal. The amorphous morphology of the seed crystal is prone to agglomeration due to its excessive specific surface area. After a short time of mixed metal salt solution supply, the necessary raw materials are provided for the surface growth of the seed crystal, the crystallinity of the seed crystal surface is improved through high temperature and high pH to promote micro ostwald ripening, and the agglomeration phenomenon caused by surface energy is reduced, so that good dispersibility is maintained during the growth stage to ensure that the secondary particles do not grow rapidly to the preset particle size due to agglomeration. When the mixed metal salt solution supply time before ripening is short, the ripening may not be complete, and the agglomeration phenomenon cannot be improved; when the mixed metal salt solution supply time before ripening is long, the seed crystal may directly promote agglomeration growth, resulting in a decrease in the sphericity of the particles.

[0039] In some preferred embodiments, in step S1, during the reaction, the ammonia concentration is 1-10 g / L, such as 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, etc.

[0040] In some preferred embodiments, in step S1, during the reaction, the temperature is 50-75℃, such as 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, etc.

[0041] In some preferred embodiments, in step S1, the oxidizing gas is fed, and the slurry discharged from the overflow port is collected after 8-30 h of reaction, such as 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, etc.; the oxidizing gas is air and / or oxygen.

[0042] In some preferred embodiments, the first target particle size is 2-4 μm, such as 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, etc.; and the second target particle size is 2.5-6.5 μm, such as 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, etc.

[0043] In some preferred embodiments, in step S1, the feeding speed of the metal salt solution is (3%-12%)V / hour, such as 3%V / hour, 4%V / hour, 5%V / hour, 6%V / hour, 7%V / hour, 8%V / hour, 9%V / hour, 10%V / hour, 11%V / hour, 12%V / hour, etc., wherein V is the volume of the reaction kettle. In some preferred embodiments, in step S1, the ammonia concentration of the first reactor bottom liquid is 1-10 g / L, such as 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, etc., the pH is 10.5-11.5, such as 10.5, 10.8, 11, 11.2, 11.5, etc., and the temperature is 50-75°C, such as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, etc.

[0044] The first reactor bottom liquid is obtained by mixing pure water, ammonia water and alkali solution.

[0045] In some preferred embodiments, in step S2, the flow rate of the mixed metal salt solution is (1.2%-12%)V / hour, such as 1.2%V / hour, 2%V / hour, 3%V / hour, 4%V / hour, 5%V / hour, 6%V / hour, 7%V / hour, 8%V / hour, 9%V / hour, 10%V / hour, 11%V / hour, 12%V / hour, etc.

[0046] In some preferred embodiments, in step S2, the pH of the second reactor bottom liquid is 8-10, such as 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, etc., the ammonia concentration is 1-20 g / L, such as 1 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 12 g / L, 15 g / L, 18 g / L, 20 g / L, etc., and the temperature is 40-60°C, such as 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, etc.

[0047] In some preferred embodiments, in step S2, the ammonia concentration of the reaction system is controlled to be 1-20 g / L, such as 1 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 12 g / L, 15 g / L, 18 g / L, 20 g / L, etc.

[0048] In some preferred embodiments, in step S2, before the maturation treatment, the pH of the reaction system is controlled to be 8-10, such as 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, etc., and the temperature of the reaction system is controlled to be 40-60°C, such as 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, etc.

[0049] In some preferred embodiments, in step S2, after the ripening treatment is completed, the pH value of the reaction system is controlled to be 9.5-11, for example, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, etc., and the temperature of the reaction system is controlled to be 45-80℃, for example, 45℃, 48℃, 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, 80℃, etc.

[0050] In some preferred embodiments, in step S2, the ripening time after the ripening treatment is 5-50h, for example, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, etc.

[0051] In some preferred embodiments, in step S2, the temperature is increased by 5-20℃ before the ripening treatment. For example, the temperature is increased by 5℃, 8℃, 10℃, 12℃, 15℃, 18℃, 20℃, etc. When the temperature increase is low, the thermal motion of the molecules is limited, which leads to a significant increase in the ripening time. When the temperature increase is too high, it is difficult to stably control the temperature with the equipment, and unnecessary energy is wasted.

[0052] In some preferred embodiments, in step S2, during the ripening treatment, an alkali solution is introduced into the reaction kettle, and the pH value is increased by 0.2-0.6 per hour until the pH value is 9.5-11.0. The pH value increase rate can be 0.2 / hour, 0.25 / hour, 0.3 / hour, 0.35 / hour, 0.4 / hour, 0.45 / hour, 0.5 / hour, 0.55 / hour, 0.6 / hour, etc., and the target pH value can be 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, etc. When the pH value increases too fast during the ripening process, secondary nucleation may be induced. When the pH value increases too slowly during the ripening process, the raw material supply is insufficient, leading to incomplete ripening.

[0053] In some preferred embodiments, in step S2, the total ripening time of the ripening treatment is 2-4h, for example, 2h, 2.5h, 3h, 3.5h, 4h, etc. Short ripening time also leads to incomplete ripening, and too long ripening time does not continue to improve the crystallinity and wastes unnecessary energy supply.

[0054] The mixed metal salt solution is a mixed metal salt solution of Ni, Co, and Mn, which can be a soluble salt solution such as a sulfate salt solution.

[0055] The total metal salt concentration of the mixed metal salt solution is 1.6-2.2 mol / L, for example, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L, etc.; the concentration of the ammonia water is 4-15 mol / L, for example, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L, 13 mol / L, 14 mol / L, 15 mol / L, etc.; and the alkali solution is NaOH solution, and the concentration is 5-11 mol / L, for example, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, etc.

[0056] Some embodiments of the present application provide a high-power positive electrode material, which is prepared by using the precursor described above or the precursor prepared by the preparation method described above.

[0057] Some embodiments of the present application provide a secondary battery, which comprises the high-power positive electrode material described above.

[0058] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0059] Unless otherwise defined, all the professional terms used below have the same meaning as understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present application.

[0060] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0061] The characterization means of the precursors prepared in the following examples and comparative examples are as follows: Shell thickness and core and precursor diameter measurement: First, the precursor powder is cut by an ion beam, and then a precursor cross-sectional SEM image is taken. Then, the diameters of the core region and the secondary particles of the precursor are measured by SEM measurement software, such as Nano Measurer. In order to more accurately reflect the core proportion, the diameters of the core and the secondary particles are measured 10 times or more from different directions of the precursor cross-section, and the average value is taken as the diameter. Further, the core diameter / secondary particle diameter ratio of 10 or more precursor particles is calculated to obtain the proportion of the core in the precursor.

[0062] Oil absorption measurement: Weigh 40g of powder sample and place it in the Haitai-Luxembourg DABS-01 mixing chamber, while simultaneously adding paraffin oil dropwise at a constant rate. As the liquid is gradually absorbed by the material, the powder gradually changes from a free-flowing state to a semi-plastic agglomerate, increasing the viscosity of the mixture and causing the stirring torque to rise. When the torque reaches a preset threshold, stop adding liquid. The volume of liquid consumed at this point is the oil absorption value (unit: mL / 100g).

[0063] Example 1 Step (I) Preparation of the core region precursor. Prepare a mixed metal salt solution with a molar concentration of 2 mol / L and a molar ratio of nickel, cobalt, and manganese of 5:2:3. Add water to a 100L reactor until overflow, then add ammonia (10 mol / L) to adjust the ammonia concentration to 5 g / L. Adjust the temperature to 50℃ and the pH to 11.3 (using NaOH solution to adjust the pH). Control the volume of the mixed metal salt solution entering the reactor per hour to be 7% of the reactor volume, i.e., 117 mL / min, and proceed with the reaction. During the reaction... The ammonia concentration and temperature inside the reactor were maintained constant by adjusting the flow rates of ammonia water and concentrated alkali, and the overflow valve was opened to allow overflow. The pH value was adjusted to stabilize the particle size (D50) of the slurry in the reactor at 2.6~2.8μm. Then, the diaphragm pump was turned on to pump the slurry into the thickener. After concentration, the slurry was returned to the reactor. The effluent flow rate of the thickener was adjusted to control the solid content in the reactor at approximately 300g / L. Finally, air was introduced to maintain an oxygen content of 8% above the reactor. After 25 hours of reaction, the slurry discharged from the overflow port was collected. A portion of the slurry was filtered and dried to obtain a D50 of 2.7μm and a TD of 0.57g / cm³. 3 SSA is 87.64m 2 A precursor with a spherical, amorphous, amorphous core region and an oil absorption of 105.7 mL / 100g is shown in the SEM image below. Figure 1 As shown, by Figure 1 It can be seen that the precursor's core is loose and porous, with a spherical or near-spherical morphology, as shown in the XRD pattern. Figure 2 As shown, by Figure 2 It can be seen that the precursor core is an amorphous core (seed crystal) and contains sodium sulfate impurities (because the impurities were not washed off before drying). The peak width of the diffraction peak of the 001 crystal plane of the amorphous core is 0.864° (deg).

[0064] Step (II), growing the outer shell. The reaction slurry collected in Step (I) is washed, filtered, and dried to serve as seed crystals. A bottom solution with pH 9.0, ammonia concentration of 7 g / L, and temperature of 50°C is prepared in a 100L reactor. After adding 4 kg of seed crystals to the bottom solution and stirring evenly, a mixed metal salt solution, ammonia water, and alkali solution are fed into the bottom solution in a parallel flow at a rate of 80 mL / min. The ammonia concentration, temperature, and pH in the reactor are maintained constant. After reacting for 1 hour, the supply of the mixed metal salt solution, ammonia water, and alkali solution is cut off. The temperature is raised to 65°C, and then the alkali solution is slowly supplied. The pH is increased by 0.4 per hour. After 2 hours, the pH rises to 9.8. After continuing to mature for another 2 hours, the mixed metal salt solution, ammonia water, and alkali solution are fed back into the reactor in a parallel flow, while maintaining the temperature (65°C), pH (9.8), and ammonia concentration (7 g / L) in the reactor constant. The reaction is continued for 30 hours to obtain the precursor slurry. After aging, washing, filtering, and drying, the precursor slurry yielded a D50 of 4.5 μm and a TD of 1.5 g / cm³. 3 A high-power cathode material precursor with an oil absorption capacity of 56.4 mL / 100g and a core content of 64.3% exhibiting internal porosity and a dense outer shell, as shown in the XRD pattern. Figure 3 As shown, the SEM image is as follows: Figure 4 As shown, by Figure 4 It can be seen that the precursor shell is formed by the aggregation of plate-like primary particles, and the thickness of the plate-like primary particles is 60~160nm, as shown in the cross-sectional view. Figure 5 As shown, by Figure 5 It is known that the ternary precursor includes a core and a shell, wherein the core is porous and the shell is relatively dense. Because the precursor core is loose and porous while the shell is relatively dense, it has a high oil absorption capacity. The provided precursor forms a uniform porous structure inside the cathode material after sintering, which can improve electrolyte wetting, enhance rate performance, and facilitate capacity utilization. The dense shell formed on the outside of the cathode material helps improve particle strength, making it less prone to collapse during cycling, and thus improving the cycle performance of high-power cathode materials.

[0065] The reactions in steps (I) and (II) were carried out under conventional stirring with a linear velocity of 4 to 7.5 m / s.

[0066] Example 2 The difference from Example 1 is that the oxygen content above the reactor in step (i) is 6%. The resulting spherical amorphous core precursor has a D50 of 2.67 μm and a TD of 0.72 g / cm³. 3 SSA is 61.3m 2 / g, oil absorption is 89.8mL / 100g, and the diffraction peak width of the 001 crystal plane with amorphous core is 0.832°.

[0067] Step (two) is the same as example 1, the D50 of the final precursor is 4.5 μm, the TD is 1.8 g / cm 3 , the oil absorption is 43.3 mL / 100 g, and the core ratio is 63.7%. The cross-sectional SEM image of the precursor is shown in Figure 6 .

[0068] Example 3 The difference from example 1 is that the reaction time after maturation in step (two) is different, which is 10 h, and the final product precursor D50 is 3.3 μm, the TD is 0.9 g / cm 3 , the oil absorption is 73.4 mL / 100 g, and the core ratio is 78.8% of the internal porous, dense shell high-power positive electrode material precursor. The cross-sectional SEM image of the precursor is shown in Figure 7 .

[0069] Example 4 Step (one), prepare the core area precursor. Prepare a mixed metal salt solution with a molar concentration of 2 mol / L of nickel, cobalt, and manganese with a molar ratio of 5:2:3, add water to the overflow port in a 100 L reaction kettle, add ammonia water (concentration of 10 mol / L) to adjust the ammonia concentration to 1 g / L, adjust the temperature to 60 ℃, adjust the pH to 10.5 (use NaOH solution to adjust the pH value), control the volume of mixed metal salt solution entering the reaction kettle per hour to be 12% of the volume of the reaction kettle, that is, 200 mL / min, carry out the reaction, and maintain the ammonia concentration and temperature in the kettle unchanged during the reaction by adjusting the flow of ammonia water and concentrated alkali, and open the overflow valve to overflow. By adjusting the pH value, the slurry particle size D50 in the reaction kettle is stabilized at 3.5~3.7 μm, then the diaphragm pump is started to pump the slurry into the thickener, and after thickening, it is returned to the reaction kettle. Adjust the clear flow of the thickener to control the solid content in the reaction kettle to about 300 g / L, and finally introduce air to maintain the oxygen content in the upper space of the reaction kettle at 5.5%. After 8 h of reaction, the slurry discharged from the overflow port is collected. Part of the slurry is filtered and dried to obtain a spherical amorphous core area precursor with a D50 of 3.6 μm, a TD of 0.75 g / cm 3 , a SSA of 53.73 m 2 / g, and an oil absorption of 81.5 mL / 100 g. The diffraction peak width of the 001 crystal plane of the amorphous core is 0.805°.

[0070] Step (two), growing the shell. The reaction slurry collected in step (one) is filtered, washed with water, and dried to serve as seed crystals. A 100 L reactor is prepared with a bottom solution having a pH of 8.0, an ammonia concentration of 1 g / L, and a temperature of 55°C. After the seed crystals are added to the bottom solution and stirred uniformly, a mixed metal salt solution, ammonia, and lye are concurrently fed into the reactor at a rate of 20 mL / min. The ammonia concentration, temperature, and pH in the reactor are maintained constant, and the reaction is allowed to proceed for 1 h. After the mixed metal salt solution, ammonia, and lye are cut off, the temperature is raised to 75°C, and lye is slowly fed in. The pH is increased by 0.5 every hour, and after 3 h, the pH is increased to 9.5. The mixed metal salt solution, ammonia, and lye are concurrently fed into the reactor again, and the temperature (75°C), pH (9.5), and ammonia concentration (1 g / L) in the reactor are maintained constant. The reaction is allowed to proceed for 50 h to obtain a precursor slurry. After the precursor slurry is aged, washed, filtered, and dried, a high-power positive electrode material precursor having a D50 of 4.5 μm, a TD of 1.67 g / cm 3 , an oil absorption of 46.5 mL / 100 g, and an internal porous shell dense internal core ratio of 82.1% is obtained.

[0071] The reactions in steps (one) and (two) are performed under conventional stirring, and the linear velocity is 4-7.5 m / s.

[0072] Example 5 Step (one), preparation of the internal core region precursor. A mixed metal salt solution having a molar concentration of 2 mol / L and a molar ratio of nickel, cobalt, and manganese of 5:2:3 is prepared. A 100 L reactor is filled with water to the overflow port, and ammonia (concentration of 10 mol / L) is added to adjust the ammonia concentration to 10 g / L. The temperature is adjusted to 55°C, and the pH is adjusted to 11 (NaOH solution is used to adjust the pH). The volume of the mixed metal salt solution fed into the reactor per hour is controlled to be 3% of the volume of the reactor, i.e., 50 mL / min. The reaction is performed while the ammonia concentration and temperature in the reactor are maintained constant by adjusting the flow rates of ammonia and concentrated lye, and the overflow valve is opened to overflow. The slurry particle size D50 in the reactor is stabilized at 1.9-2.1 μm by adjusting the pH, and then a diaphragm pump is started to pump the slurry into a concentrator and back to the reactor. The outflow from the concentrator is adjusted to control the solid content in the reactor to be about 400 g / L, and finally air is fed to maintain the oxygen content in the upper space of the reactor to be 10%. After 30 h, the slurry discharged from the overflow port is collected. Part of the slurry is filtered and dried to obtain an internal core region precursor having a D50 of 2 μm, a TD of 0.52 g / cm 3 , an SSA of 93.4 m 2 / g, and an oil absorption of 118.6 mL / 100 g, which is a spherical amorphous internal core region precursor having an amorphous morphology. The diffraction peak width of the 001 crystal plane of the amorphous internal core is 0.882°.

[0073] Step (two), growing the shell. The reaction slurry collected in step (one) was washed with water, filtered, and spun dry to serve as seeds. A 100 L reactor was prepared with a bottom solution having a pH of 10.0, an ammonia concentration of 15 g / L, and a temperature of 60°C. After the 4 kg of seeds were stirred uniformly in the bottom solution, a mixed metal salt solution, ammonia, and lye were concurrently fed into the reactor at a rate of 200 mL / min. The ammonia concentration, temperature, and pH in the reactor were maintained constant, and the reaction was allowed to proceed for 1 h. After the mixed metal salt solution, ammonia, and lye were cut off, the temperature was increased to 65°C, and the lye was slowly fed in. The pH was increased by 0.5 every hour, and after 2 h, the pH was increased to 11. The reactor was allowed to mature for another hour, and then the mixed metal salt solution, ammonia, and lye were concurrently fed in again. The temperature (65°C), pH (11), and ammonia concentration (15 g / L) in the reactor were maintained constant, and the reaction was allowed to proceed for 5 h. The precursor slurry was obtained. After aging, washing, filtering, and drying, the precursor slurry was obtained, which had a D50 of 2.8 μm, a TD of 0.9 g / cm 3 , an oil absorption of 83.6 mL / g, and an inner core ratio of 72%. The precursor was a high-power positive electrode material with a porous inner core and a dense shell.

[0074] The reactions in steps (one) and (two) were both performed under conventional stirring, with a linear velocity of 4-7.5 m / s.

[0075] Comparative Example 1 The only difference between this comparative example and Example 1 was that the solid content in step S1 was 120 g / L.

[0076] Step (one), preparation of the inner core region precursor. A mixed metal salt solution was prepared with a molar concentration of 2 mol / L, a molar ratio of nickel, cobalt, and manganese of 5:2:3. The solution was added to a 100 L reactor until it overflowed. Ammonia (10 mol / L) was added to adjust the ammonia concentration to 5 g / L. The temperature was adjusted to 50°C, and the pH was adjusted to 11.3 (NaOH solution was used to adjust the pH). The volume of the mixed metal salt solution fed into the reactor per hour was 7% of the volume of the reactor, i.e., 117 mL / min. The ammonia concentration and temperature in the reactor were maintained constant by adjusting the flow rates of ammonia and lye. The overflow valve was opened to overflow. The pH was adjusted to stabilize the particle size D50 of the slurry in the reactor to 2.6-2.8 μm. The slurry was then pumped into a concentrator by a diaphragm pump and returned to the reactor after being concentrated. The flow rate of the clear liquid from the concentrator was adjusted to control the solid content in the reactor to 120 g / L. Air was then fed in to maintain the oxygen content in the headspace of the reactor at 8%. After 25 h of reaction, the slurry discharged from the overflow port was collected. Part of the slurry was filtered and dried to obtain a precursor with a D50 of 37.6 μm (the material was severely agglomerated after drying, and the test value was artificially increased due to the hardening of the material), a TD of 0.41 g / cm 3 , and an SSA of 97.8 m 2The precursor in the core region, with an oil absorption of 130.2 mL / 100 g, has a diffraction peak width of 0.903° on the 001 crystal plane of the core. SEM images are shown below. Figure 8 As shown, by Figure 8 As can be seen, the obtained kernels agglomerated into large clumps. Analysis suggests that this may be because the comparative example underwent strong oxidation during the kernel preparation stage due to low solid content. The resulting particles were too fine and agglomerated into clumps after drying, failing to achieve a spherical morphology. This also led to an abnormally high D50 value in the particle size analysis.

[0077] Step (II), growing the outer shell. The reaction slurry collected in Step (I) is washed, filtered, and dried to serve as seed crystals. A bottom solution with pH 9.0, ammonia concentration of 7 g / L, and temperature of 50°C is prepared in a 100L reactor. After adding 4 kg of seed crystals to the bottom solution and stirring evenly, a mixed metal salt solution, ammonia water, and alkali solution are fed into the bottom solution in a parallel flow at a rate of 80 mL / min. The ammonia concentration, temperature, and pH in the reactor are maintained constant. After reacting for 1 hour, the supply of the mixed metal salt solution, ammonia water, and alkali solution is cut off. The temperature is raised to 65°C, and then the alkali solution is slowly supplied. The pH is increased by 0.4 per hour. After 2 hours, the pH rises to 9.8. After continuing to mature for another 2 hours, the mixed metal salt solution, ammonia water, and alkali solution are fed back into the reactor in a parallel flow, while maintaining the temperature (65°C), pH (9.8), and ammonia concentration (7 g / L) in the reactor constant. The reaction is continued for 30 hours to obtain the precursor slurry. After aging, washing, filtering, and drying, the precursor slurry yielded a D50 of 3.9 μm and a TD of 1.02 g / cm³. 3 It is a cathode material precursor with an oil absorption capacity of 86.2 mL / 100g and a core content of 68%.

[0078] The reactions in steps (I) and (II) were carried out under conventional stirring with a linear velocity of 4 to 7.5 m / s.

[0079] Comparative Example 2 The only difference between this comparative example and Example 1 is that the oxygen content is different in step S1, and the oxygen content is 0.5%.

[0080] Step (I), preparation of the core region precursor. A mixed metal salt solution with a molar concentration of 2 mol / L and a molar ratio of nickel, cobalt and manganese of 5:2:3 is prepared. The solution is added to a 100 L reactor until it overflows. Ammonia (concentration of 10 mol / L) is added to adjust the ammonia concentration to 5 g / L. The temperature is adjusted to 50°C and the pH is adjusted to 11.3 (NaOH solution is used to adjust the pH). The volume of mixed metal salt solution added to the reactor per hour is controlled to be 7% of the volume of the reactor, i.e. 117 mL / min. The ammonia concentration and temperature in the reactor are maintained constant by adjusting the flow rates of ammonia and concentrated alkali during the reaction. The overflow valve is opened to overflow. The slurry particle size D50 in the reactor is stabilized at 2.6-2.8 μm by adjusting the pH. The slurry is then pumped into a thickener by a diaphragm pump. After thickening, the slurry is returned to the reactor. The overflow flow rate of the thickener is adjusted to control the solid content in the reactor to about 300 g / L. Finally, air is introduced to maintain the oxygen content in the headspace of the reactor at 0.5%. After 25 h of reaction, the slurry discharged from the overflow is collected. Part of the slurry is filtered and dried to obtain a core region precursor with a D50 of 2.7 μm, a TD of 1.28 g / cm 3 , a SSA of 22 m 2 / g and an oil absorption of 57 mL / 100 g. The diffraction peak width of the 001 crystal plane of the core is 0.398°. The SEM image is shown in Figure 9 . As can be seen from the SEM image, the primary particles of the core have high crystallinity and the thickness of the primary particles is relatively high. Figure 9 In Comparative Example 2, the oxygen content in the reactor is insufficient during the preparation of the core, the precursor is not oxidized sufficiently, the primary particles are too thick, the TD of the core precursor is too high, the SSA and the oil absorption are small, and the TD of the final precursor synthesized using the core precursor as a seed is also significantly increased, and the SSA and the oil absorption are significantly reduced.

[0081] Step (II), growth of the shell. The reaction slurry collected in Step (I) is washed, filtered, dried and used as a seed. A bottom solution with a pH of 9.0, an ammonia concentration of 7 g / L and a temperature of 50°C is prepared in a 100 L reactor. After stirring the 4 kg of seed in the bottom solution, 80 mL / min of mixed metal salt solution, ammonia and alkali are introduced into the bottom solution in the reactor. The ammonia concentration, temperature and pH in the reactor are maintained constant. After 1 h of reaction, the supply of mixed metal salt solution, ammonia and alkali is stopped. The temperature is increased to 65°C and alkali is slowly supplied. The pH is increased by 0.4 per hour. After 2 h, the pH is increased to 9.8. After 2 h of aging, mixed metal salt solution, ammonia and alkali are introduced into the reactor again. The temperature (65°C), pH (9.8) and ammonia concentration (7 g / L) in the reactor are maintained constant. After 30 h of reaction, a precursor slurry is obtained. After aging, washing, filtering and drying, a precursor with a D50 of 4.57 μm and a TD of 1.78 g / cm 3, the SEM image of which is shown in Fig. 1, the oil absorption is 30.2 mL / 100 g, and the proportion of the core is 53%. Figure 10

[0082] The reactions in steps (I) and (II) are carried out under conventional stirring, and the linear velocity is 4-7.5 m / s.

[0083] Comparative Example 3 The difference between this comparative example and Example 1 is that the ripening process is omitted in step S2.

[0084] Step (I), preparation of the core region precursor. A mixed metal salt solution with a molar concentration of 2 mol / L and a molar ratio of nickel, cobalt and manganese of 5:2:3 is prepared, and water is added to the overflow port of a 100 L reaction kettle. Ammonia water (concentration of 10 mol / L) is added to adjust the ammonia concentration to 5 g / L, the temperature is adjusted to 50°C, the pH is adjusted to 11.3 (NaOH solution is used to adjust the pH value), the volume of the mixed metal salt solution entering the reaction kettle per hour is controlled to be 7% of the volume of the reaction kettle, i.e. 117 mL / min, the reaction is carried out, and during the reaction, the ammonia concentration and temperature in the kettle are maintained unchanged by adjusting the flow rates of ammonia water and concentrated alkali, and the overflow valve is opened to overflow. The particle size D50 of the slurry in the reaction kettle is stabilized at 2.6-2.8 μm by adjusting the pH value, then a diaphragm pump is started to pump the slurry into a concentrator, and after concentration, the slurry is returned to the reaction kettle. The overflow flow rate of the concentrator is adjusted to control the solid content in the reaction kettle to about 300 g / L, and finally air is introduced to maintain the oxygen content above the reaction kettle at 8%. After 25 h of reaction, the slurry discharged from the overflow port is collected. Part of the slurry is filtered and dried to obtain a core region precursor with a D50 of 2.7 μm, a TD of 0.57 g / cm 3 , an SSA of 87.64 m 2 / g, and an oil absorption of 105.7 mL / 100 g. The diffraction peak width of the 001 crystal plane of the core is 0.864°.

[0085] Step (II), growth of the shell. The reaction slurry collected in step (I) is filtered, dried and used as a seed crystal. A 100 L reaction kettle is prepared with a bottom liquid having a pH of 9.0, an ammonia concentration of 7 g / L and a temperature of 50°C. After stirring the 4 kg seed crystal in the bottom liquid uniformly, 80 mL / min of mixed metal salt solution, ammonia water and alkali solution are introduced into the bottom liquid of the reaction kettle in parallel flow, and the ammonia concentration, temperature and pH in the kettle are maintained unchanged. After 30 h of reaction, a precursor slurry is obtained. After aging, washing, filtering and drying, an anode material precursor with a D50 of 5.2 μm, a TD of 1.34 g / cm 3 , an oil absorption of 60.2 mL / 100 g, and a core proportion of 65.1% is obtained, and the SEM image is shown in Fig. 2. Figure 10 Figure 11 ​​It can be seen that, due to omitting the ripening process in the preparation of the shell stage, the particle dispersibility of the comparative example is poor, and the agglomeration is serious during the synthesis, and the sphericity of the final precursor is poor.

[0086] The reactions in steps (I) and (II) are both carried out under conventional stirring, and the linear velocity is 4-7.5 m / s.

[0087] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A high-power cathode material precursor, characterized in that, The precursor is a ternary precursor, which includes a core and a shell. The core is porous and the shell is relatively dense. The oil absorption capacity of the precursor is 40~85mL / 100g.

2. The high-power cathode material precursor as described in claim 1, characterized in that, The high-power cathode material precursor has at least one of the following technical features: (a) The morphology of the kernel is amorphous, quasi-spherical amorphous morphology; (b) The oil absorption capacity of the core is 80~120mL / 100g; (c) The kernel diameter D50 is 2.0 μm to 4.0 μm; (d) The tap density (TD) of the core is 0.5~0.8 g / cm³. 3 ; (e) The specific surface area of ​​the kernel is 50~95m². 2 / g; (f) The outer shell is formed by the aggregation of sheet-like primary particles; the thickness of the sheet-like primary particles is 60~160nm; (g) The ratio of the kernel diameter to the precursor diameter is 65-90%; (h) The shell thickness is 0.25~0.8μm, preferably 0.25~0.6μm; (i) The particle size D50 of the precursor is 2.5~6.5 μm; (j) The tap density of the precursor is 0.8~1.9 g / cm³. 3 ; (k) The chemical formula of the precursor is Ni x Co y Mn z (OH)2, where 0.3≤x≤0.7, 0≤y≤0.3, 0≤z≤0.5, and x+y+z=1.

3. A method for preparing a high-power cathode material precursor, characterized in that, include: S1. Core Preparation: A mixed metal salt solution, ammonia, and alkaline solution are introduced concurrently into the bottom liquid of the first reaction vessel for reaction. Overflow occurs during the reaction. After the particle size stabilizes at the first target particle size D50, the slurry is concentrated and returned to the reaction vessel. The solid content in the reaction vessel is controlled at 201 g / L to 450 g / L. After the solid content stabilizes, an oxidizing gas is introduced to maintain the oxygen content in the reaction atmosphere above the slurry in the reaction vessel at 5.1% to 10%. After reacting for a period of time, the slurry discharged from the overflow port is collected. The obtained slurry is washed and subjected to solid-liquid separation to obtain the precursor core seed crystal with the first target particle size D50. The metal in the mixed metal salt solution includes nickel and at least one selected from cobalt and manganese. S2. Shell preparation: The precursor core seed crystal is added to the bottom liquid of the second reaction vessel. After stirring, a mixed metal salt solution, ammonia water and alkaline solution are introduced into the bottom liquid of the second reaction vessel in parallel to carry out the reaction. After 0.5~1.5h, the introduction of mixed metal salt solution, ammonia water and alkaline solution is stopped, and the temperature is raised for aging treatment. After aging is completed, the mixed metal salt solution, ammonia water and alkaline solution are introduced into the bottom liquid of the second reaction vessel in parallel to carry out the reaction until the precursor grows to the second target particle size D50. The resulting slurry is aged, washed, solid-liquid separated and dried to obtain the high-power cathode material precursor.

4. The method for preparing the high-power cathode material precursor as described in claim 3, characterized in that, In step S1, the ammonia concentration during the reaction is 1~10 g / L; In step S1, the reaction temperature is 50~75℃; In step S1, an oxidizing gas is introduced, and after reacting for 8 to 30 hours, the slurry discharged from the overflow outlet is collected; the oxidizing gas is air and / or oxygen. The first target particle size D50 is 2.0 μm to 4.0 μm; the second target particle size D50 is 2.5 to 6.5 μm.

5. The method for preparing the high-power cathode material precursor as described in claim 3, characterized in that, In step S1, the rate at which the metal salt solution is introduced is (3%~12%)V / hour, where V is the volume of the reactor. In step S1, the ammonia concentration of the bottom liquid of the first reaction vessel is 1~10 g / L, the pH is 10.5~11.5, and the temperature is 50~75℃.

6. The method for preparing the high-power cathode material precursor as described in claim 3, characterized in that, In step S2, the flow rate of the mixed metal salt solution is (1.2%~12%)V / hour; In step S2, the pH value of the bottom liquid of the second reaction vessel is 8~10, the ammonia concentration is 1~20g / L, and the temperature is 40~60℃.

7. The method for preparing the high-power cathode material precursor as described in claim 3, characterized in that, In step S2, the ammonia concentration in the reaction system is controlled to be 1~20 g / L; In step S2, before the aging process, the pH of the reaction system is controlled to be 8-10, and the temperature of the reaction system is controlled to be 40-60℃. In step S2, after the aging process is completed, the pH value of the reaction system is controlled to be 9.5~11, and the temperature of the reaction system is controlled to be 45~80℃.

8. The method for preparing the high-power cathode material precursor as described in claim 3, characterized in that, In step S2, the reaction time after ripening is 5 to 50 hours; In step S2, the temperature of the reaction system is raised by 5-20°C before the ripening treatment; In step S2, during the ripening process, an alkaline solution is introduced into the second reaction vessel, and the pH value is increased by 0.2 to 0.6 per hour until the pH value is 9.5 to 11.0; In step S2, the total duration of the ripening process is 2 to 4 hours.

9. A high-power cathode material, characterized in that, The precursor prepared by the precursor as described in claim 1 or 2 or by the preparation method as described in any one of claims 3 to 8 is mixed with lithium salt and then sintered. Alternatively, the precursor prepared by the method described in claim 1 or 2, or by any one of the preparation methods described in claims 3 to 8, can be mixed with lithium salt and dopant and then sintered.

10. A secondary battery, characterized in that, Including the high-power cathode material as described in claim 9.

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