Preparation method of high-performance single-crystal porous large-core NCM high-nickel ternary precursor

Abstract

The invention belongs to the technical field of high-nickel ternary precursors, and relates to a preparation method of a high-performance single-crystal porous large-core NCM high-nickel ternary precursor. The method comprises the following steps: firstly, precisely filtering a metal salt mixed solution, a complexing agent solution and a precipitant solution; and then by utilizing the mixing form and strength of the feed liquid in different flow fields and the growth characteristics of the particles in different atmospheres, accurate control of particle nucleation and growth is realized, so that the material grows into the high-nickel ternary precursor material with single-crystal morphology and porous large-core structural characteristics. The single-crystal porous large-core NCM high-nickel precursor prepared by the method has the advantages of excellent morphology, clear crystal form, high crystallinity, high pore volume, high specific capacity, good cycle stability and thermal stability.

Description

Technical Field

[0001] The invention belongs to the technical field of high-nickel ternary precursors in material engineering, and specifically relates to a method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor. Background Art

[0002] As the new energy vehicle industry gradually matures, downstream terminal consumers have increasing requirements for new energy vehicle power performance, endurance, safety, cost-effectiveness and other indicators. Power batteries also need to find a balance between the ever-increasing energy density, safety and cost-effectiveness. In a system that pursues high specific energy as the main line of development and high safety as the red line of consideration, the current technical direction is to increase capacity and voltage, the former corresponds to high nickel content, and the latter corresponds to single crystal. In order to meet consumers' requirements for new energy vehicle power performance and endurance, most ternary lithium-ion battery manufacturers achieve the above performance requirements by increasing the nickel content in the ternary positive electrode material. High nickel content, single crystal and low cobalt content have become one of the industry's technical trends.

[0003] The patent with publication number CN113373500A discloses a high nickel single crystal ternary precursor and a preparation method thereof, the method comprising: 2+ 、Co 2+ , Mn 2+ and potassium manganate (III) trioxalate to prepare a mixed salt solution according to the general formula. The Mn 3+ With Mn 2+ The molar ratio of is 2 to 4, so as to refine the primary particles of the secondary particles and increase the specific surface area. The mixed salt solution, the precipitant solution and the complexing agent solution are added to the reactor to react to generate a high-nickel single crystal ternary precursor slurry. Then filter press, wash and dry to obtain a high-nickel single crystal ternary precursor. The primary particles are flaky and have a thickness of 50 to 110 nm. The technical problems of the capacity attenuation of the material caused by the mixed arrangement of nickel and lithium cations and the inappropriate thickness of the primary particles during the subsequent mixed calcination of the existing high-nickel single crystal ternary precursor with a lithium source are solved. Although the high-nickel single crystal material prepared by the above method can effectively solve the problem of material capacity attenuation caused by the mixed arrangement of nickel and lithium cations during the mixed calcination process, its raw materials are complex, the mother liquor treatment is more difficult than conventional, and the cost of industrial production is high.

[0004] The patent with publication number CN116199272A discloses a method for preparing a single crystal ternary precursor. The method comprises preparing a nickel-cobalt-manganese metal mixed salt solution, adding a precipitant and a complexing agent to a first reactor containing a bottom liquid under the protection of an inert gas, and performing a coprecipitation reaction to obtain a slurry; adding the slurry to a second reactor, and then adding the nickel-cobalt-manganese metal mixed salt solution, a precipitant and a complexing agent, and simultaneously introducing an oxygen-containing inert gas to perform a coprecipitation reaction; when the material fills the second reactor, a concentrator is used for concentration treatment, and oxygen-containing inert gas is continuously introduced to grow the average particle size of the material in the reactor to a target value; the material in step (3) is subjected to solid-liquid separation, aging, washing, and drying treatment to obtain a precursor. The above method uses two kettles to prepare slurry and long balls respectively, and the operation is relatively cumbersome and the production efficiency is limited.

[0005] The patent with publication number CN118084080A discloses a single crystal ternary precursor, anode material and preparation method. The patent contains a single crystal ternary precursor, D50 = 1 ~ 2um, a primary particle size of 10-100nm, and a tap density of 1.0 ~ 2.0g / cm 3 , with a specific surface area of ​​100 to 150 m 2 / g. Also disclosed is a method for preparing a single crystal ternary precursor, a method for preparing a single crystal ternary cathode, and a single crystal ternary cathode material. The nickel-cobalt-manganese ternary precursor prepared by the present invention has an extremely small particle size, and the primary particle size does not exceed 20nm. The product has extremely high activity. The above method first adds nickel-cobalt-manganese metal salt to the reactor, then adds solid ammonium sulfate to adjust the ammonia value, then adds dilute sulfuric acid or dilute hydrochloric acid to adjust the pH, and then adds alkali solution to react. The process is complicated and the industrial production control is difficult. If dilute hydrochloric acid is used, Cl in the mother liquor wastewater will - The processing cost is high. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a high-performance single crystal porous large core structure high-nickel NCM ternary precursor in view of the development direction of the existing high-nickel single crystal technology.

[0007] The technical solutions adopted by the present invention to achieve the above technical objectives are as follows:

[0008] A method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor comprises the following steps:

[0009] Step (1): Mix soluble nickel salt, cobalt salt, manganese salt and pure water according to the required Ni 2+ 、Co 2+ , Mn 2+ The required metal salt mixed solution is prepared in the required proportion, and the complexing agent solution and the precipitant solution are prepared in the required concentration;

[0010] Step (2): Precisely filter the metal salt mixed solution, liquid alkali solution, and ammonia water solution in step (1) respectively to remove tiny solid particles in the solution and ensure product quality;

[0011] Step (3): Connect the reaction kettle and the concentrator in series and add pure water for circulation. In a non-inert atmosphere, adjust the kettle temperature, stirring frequency, ammonia value, and alkalinity to the established targets as the bottom liquid;

[0012] Step (4): Pass the metal salt mixed solution filtered in step (2) through the feed pipe above the outer edge of the middle stirring paddle, and at the same time add the precipitant solution and complexing agent solution into the reaction system in step (3) through the corresponding feed pipes for precipitation reaction. Control the residual alkali and ammonia value in the non-inert atmosphere to nucleate to the target nucleation particle size;

[0013] Step (5): After the D50 in step (4) grows to the target nucleation particle size, introduce an inert gas into the reaction system. At the same time, adjust the metal salt mixed solution to be added to the reaction kettle through the feed pipe above the outer edge of the lower stirring paddle. The feeding methods and positions of the precipitant solution and complexing agent solution remain unchanged, change the material mixing method in the kettle, and continue the concentration co-precipitation reaction to the target particle size; Control the residual alkali to decrease by 0.02 - 0.1 g / L every 1 h of reaction until it drops below 0.6 g / L;

[0014] Step (6): After step (5) reaches the target particle size, stop feeding, and perform post-treatment steps such as aging, washing, drying, sieving, and iron removal to obtain a single-crystalline porous large-core structure high-nickel NCM ternary precursor.

[0015] By adopting the above technical solutions, nucleation is carried out in a non-inert atmosphere and growth is carried out in an inert atmosphere. At the same time, by changing the feeding position during the nucleation and growth reaction processes to change the material mixing method, it is helpful to obtain a loose and porous hollow large-core structure, and the obtained precursor particles have good sphericity, good dispersibility, and high crystallinity.

[0016] Preferably, the component ratio of the metal salt mixed solution in step (1) is Ni 2+ : Co 2+ : Mn 2+ meeting: Ni x Co y Mn z (OH)2, where x + y + z = 1, 0.8 ≤ x < 1, 0 < y < 0.2, 0 < z < 0.2, and the total metal ion concentration is preferably 1.5 - 2.0 mol / L.

[0017] Preferably, the complexing agent and precipitant in step (1) are the complexing agent and precipitant for conventional co-precipitation reactions; more preferably, the complexing agent is ammonia water with a concentration of 15% - 20%, and the precipitant is liquid alkali with a concentration of 26% - 32%.

[0018] Preferably, the soluble nickel salt, cobalt salt and manganese salt in step (1) are nickel sulfate, cobalt sulfate and manganese sulfate.

[0019] Preferably, the precision filtration in step (2) is carried out by filtering through a microporous precision filter, and the filtration accuracy of the microporous precision filter is 0.5 μm.

[0020] Preferably, in step (3), the kettle temperature is controlled at 60-70° C., the frequency of the frequency converter of the stirring paddle is controlled at 45±1 Hz, the bottom liquid ammonia value is controlled at 6.0-6.5 g / L, and the residual alkali is controlled at 3.1-3.3 g / L.

[0021] Preferably, the steps (3) and (4) are carried out under a non-inert atmosphere, which means that the feeding and / or reaction can be carried out directly without the need to pass an inert gas to exhaust the oxygen in the system.

[0022] Preferably, the feeding position of step (4) is close to 70 mm above the outer edge of the middle blade, which is named as feed pipe ① in the present invention, and the residual alkali is controlled to be 3.1-3.3 g / L, and the metal salt mixed solution is added at a rate of 300.0±5.0 L / h until the particle size grows to the target nucleation particle size D50 of 1.3-1.6 μm, and the reaction time is 10 h. More preferably, the nucleation reaction in step (4) controls the kettle temperature at 60-70°C, the frequency converter of the stirring blade is 45±1 Hz, and the ammonia value is 6.0-6.5 g / L.

[0023] Preferably, in step (5), on the basis of step (4), the feed position is adjusted to 50 mm above the outer edge of the lower stirring blade, which is named as feed pipe ② in the present invention. The flow rate of the metal salt mixed solution is adjusted from 300.0±5.0L / h when the nucleation reaction is 10h, and is adjusted according to the reaction time to 400.0±5.0L / h within 10-20h of reaction, to 450.0±5.0L / h within 20-30h, and to 500.0±5.0L / h after 30h. The discharge of the concentrator is regulated according to the feed flow rate of the reactor, so that the discharge of the concentrator mother liquor is kept in dynamic balance with the feed amount of the reactor, and the average reaction concentration time is controlled between 75 and 85h. More preferably, the growth reaction in step (5) controls the reactor temperature at 60-70°C, the frequency converter frequency of the stirring blade is 45±1Hz, and the ammonia value is 6.0-6.5g / L.

[0024] Preferably, the target particle size D50 of step (5) is 3.5 um.

[0025] Preferably, the kettle temperature, stirring, ammonia value of the nucleation reaction in step (4) and the growth reaction in step (5) are consistent with the bottom liquid conditions in step (3).

[0026] Preferably, the inert gas in step (5) is at least one of nitrogen, helium and argon, more preferably nitrogen.

[0027] Preferably, the material aged for 30 to 60 min in step (6) is sequentially subjected to alkali washing + water washing by filter pressing, wherein the alkali washing solution is a sodium hydroxide solution with a concentration of 0.50-0.90 mol / L, a temperature of 70 to 85° C., and a washing water temperature of 70 to 85° C. More preferably, the washing time is 60 to 200 min.

[0028] Preferably, the washed material is dried in a disc dryer, and the temperature of the disc dryer is controlled at 120-140°C for the upper disc, and 110-130°C for the middle and lower discs respectively.

[0029] The present invention firstly performs precision filtration on the mixed solution of metal salt, the complexing agent solution and the precipitant solution to remove tiny particles, thereby ensuring the precise control and stability of the process; then, the mixing form and strength of the feed solution in different flow fields and the growth characteristics of the particles in different atmospheres are utilized to realize the accurate control of particle nucleation and growth, so that the material grows into a high-nickel ternary precursor material with single crystal morphology and porous large core structure characteristics. The single crystal porous large core NCM high-nickel precursor prepared by the present invention has excellent morphology, clear crystal form, high crystallinity, high pore volume, high specific capacity, good cycle stability and thermal stability.

[0030] Compared with the existing process, the present invention has the following beneficial effects:

[0031] (1) Achieve full concentration in one step in a single kettle, with a short process flow, and the materials are conventionally free of additives, easy to handle, low cost, and in line with green production and manufacturing;

[0032] (2) No protective gas is introduced during the nucleation process, the kettle pressure is reduced, ammonia overflow is reduced, costs are saved, and the working environment is improved;

[0033] (3) Initial oxidation of the precursor core effectively reduces Ni during high temperature sintering 2+ or Mn 2+ To You 3+ or Mn 4+ The difficulty of oxidation is conducive to fully exerting the electrical properties of the material;

[0034] (4) The porous large core structure can effectively alleviate the volume change of the material during the sintering process and the structural damage caused by side reactions, while expanding the contact area between the active material and the electrolyte, improving the battery's endurance, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the SEM image of the NCM single crystal porous large core high nickel precursor prepared in Example 1.

[0036] Figure 2 This is a cross-sectional view of the NCM single crystal porous large core high nickel precursor prepared in Example 1.

[0037] Figure 3 This is the XRD spectrum of the NCM single crystal porous large core high nickel precursor prepared in Example 1.

[0038] Figure 4 This is a cross-sectional view of the NCM single crystal high-nickel precursor prepared in Example 2.

[0039] Figure 5 This is a cross-sectional view of the NCM single crystal high-nickel precursor prepared in Example 3.

[0040] Figure 6 This is a cross-sectional view of the NCM single crystal high-nickel precursor prepared in Example 4.

[0041] Figure 7 This is the SEM image of the NCM single crystal high nickel precursor prepared in Example 4.

[0042] Figure 8 This is the SEM image of the NCM single crystal high nickel precursor prepared in Example 5. DETAILED DESCRIPTION

[0043] In order to better clarify and understand the purpose, process scheme and advantages of the present invention, the technical scheme and implementation method of the present invention are further described clearly, completely and in detail through specific examples and in combination with the accompanying drawings. It should be noted that the embodiments described in the present invention are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given, but they are only part of the embodiments of the present invention, not all of the embodiments. The specific implementation methods described are limited to explaining and interpreting the present invention, and do not limit the present invention. Based on the embodiments in the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] The experimental methods and conditions used in the embodiments of the present invention are conventional methods and conventional conditions unless otherwise specified. The materials, reagents or instruments used in the embodiments, unless otherwise specified, can be obtained from commercial sources or prepared by conventional methods. The reaction conditions embodied in the content of the invention of the present invention can achieve the reaction and obtain the product of the expected effect. Due to space limitations, some embodiments are listed below to further illustrate the advantages of the technical solution of the present invention.

[0045] Embodiment 1:

[0046] Ni in a molar ratio of 0.92:0.04:0.04 2+ 、Co 2+ , Mn 2+Add salt to pure water and stir for 15 to 30 minutes until it is evenly mixed. Prepare ammonia water with a concentration of 20% and liquid caustic soda with a concentration of 32%. Perform precision filtration to remove tiny solid particles in the liquid and ensure the impurity content. 3 Stainless steel reactor, 3m 3 Stainless steel concentrator. Fill the reactor and concentrator with pure water in advance and circulate them, raise the reactor temperature to 65℃, control the frequency of the stirring blade inverter at 45±1Hz, adjust the ammonia value in the reactor to 6.0~6.5g / L, and the residual alkali value to 3.1-3.3g / L. During the adjustment process, the reactor and concentrator continue to circulate, and continue to circulate for 20~30min after adjusting to the established parameter value as the base liquid. This process is carried out in a non-inert atmosphere. After reaching the set requirements, the metal salt mixed solution is added to the reactor with the prepared base liquid through the material pipe ① (70mm above the outer edge of the middle stirring blade), liquid alkali, and ammonia water through the corresponding feed pipes. In the first 10h, the mixed metal salt addition rate is controlled at 300.0±5.0L / h, and the ammonia value is maintained at 6.0~6.5g / L and the residual alkali is 3.1-3.3g / L, until the nucleation particle size D50=1.5um. Start to introduce N2, and at the same time adjust the metal salt to feed into the feed pipe ② (50mm above the outer edge of the lower stirring blade). The positions of ammonia and alkali remain unchanged. The flow rate increases gradually from 400.0±5.0L / h within 10-20h to 450.0±5.0L / h within 20-30h, and to 500.0±5.0L / h after 30h. According to the flow rate of the mixed metal salt, the flow rate of ammonia water and liquid alkali is adjusted, the ammonia value is controlled at 6.0-6.5g / L, the residual alkali is gradually reduced, and the residual alkali is reduced by 0.01-0.1g / L every 1h of reaction after 10h, until the residual alkali is below 0.6g / L; the process controls the discharge of the concentrator according to the feed flow of the reactor, so that the discharge of the mother liquor of the concentrator and the feed of the reactor are kept in dynamic balance, the average reaction concentration time is controlled between 75-85h, the particle size D50 of the material in the reactor reaches the controlled particle size D50=3.0-5.0um, the feed is stopped, and the materials in the reactor and the concentrator are pumped into the aging reactor for 30-60min. The materials after post-aging are sequentially washed with alkali at a concentration of 0.50-0.90mol / L and a temperature of 70-85℃, and washed with pure water at a temperature of 70-85℃ for 60-200min. Subsequently, the above materials are dried in a tray dryer with an upper tray temperature of 120-140° C. and middle and lower tray temperatures of 110-130° C. to obtain a single-crystal porous large core structure ternary precursor.

[0047] The physical and chemical parameters of the obtained precursor are as follows: the specific surface area is 9.19m 2 / g, tap density is 1.94g / m 3 , porosity is 7.65% and D50 is 3.36um.

[0048] Figure 1This is the SEM image of the NCM single crystal porous large core structure high nickel precursor obtained in Example 1. The precursor exhibits a significant strip-shaped crystal structure and has good dispersibility. Figure 2 This is a cross-sectional view of the precursor obtained in Example 1. It can be seen from the figure that the NCM precursor has a special porous large core structure, and the inner core presents a loose network structure. Figure 3 This is the XRD spectrum of the precursor obtained in Example 1. It can be seen from the figure that it has sharp peaks, indicating that its degree of crystallization is good and the crystallinity is high.

[0049] Embodiment 2:

[0050] Ni in a molar ratio of 0.92:0.04:0.04 2+ 、Co 2+ , Mn 2+ Add salt to pure water and stir for 15 to 30 minutes until it is evenly mixed. Prepare ammonia water with a concentration of 20% and alkali solution with a concentration of 32%. Perform precision filtration to remove tiny solid particles in the solution and ensure the impurity content. 3 Stainless steel reactor, 3m 3Stainless steel concentrator. Fill the reactor and concentrator with pure water in advance and circulate them, raise the reactor temperature to 65℃, control the frequency of the agitator inverter at 45±1Hz, adjust the ammonia value in the reactor to 6.0~6.5g / L, and the residual alkali value to 3.1-3.3g / L. During the adjustment process, the reactor and concentrator continue to circulate, and after adjusting to the established parameter value, continue to circulate for 20~30min and use it as the bottom liquid, and pass N2 gas. After reaching the set requirements, add the metal salt mixed solution through the material pipe ①, liquid alkali, and ammonia water through the corresponding feed pipes to the reactor with the prepared bottom liquid. In the first 10h, control the addition rate of the mixed metal salt to 300.0±5.0L / h, maintain the ammonia value at 6.0~6.5g / L, and the residual alkali at 3.1-3.3g / L, until the nucleation particle size D50=1.5um. Keep N2 flowing, and adjust the metal salt to feed into pipe ② at the same time. The positions of ammonia and alkali remain unchanged. The flow rate increases gradually from 400.0±5.0L / h within 10-20h to 450.0±5.0L / h within 20-30h, and to 500.0±5.0L / h after 30h. According to the flow rate of the mixed metal salt, the flow rate of ammonia water and liquid alkali is adjusted, the ammonia value is controlled at 6.0-6.5g / L, the residual alkali is gradually reduced, and the residual alkali is reduced by 0.01-0.1g / L every 1h of reaction after 10h, until the residual alkali is below 0.6g / L; the process controls the discharge of the concentrator according to the feed flow of the reactor, so that the discharge of the mother liquor of the concentrator and the feed of the reactor are kept in dynamic balance, the average reaction concentration time is controlled between 75-85h, the particle size D50 of the material in the reactor reaches the controlled particle size D50=3.0-5.0um, the feed is stopped, and the materials in the reactor and the concentrator are pumped into the aging reactor for 30-60min. The materials after post-aging are sequentially washed with alkali at a concentration of 0.50-0.90mol / L and a temperature of 70-85℃, and washed with pure water at a temperature of 70-85℃ for 60-200min. Subsequently, the above materials are dried in a tray dryer with an upper tray temperature of 120-140° C. and middle and lower tray temperatures of 110-130° C. to obtain a single-crystal porous large core structure ternary precursor.

[0051] The physical and chemical parameters of the obtained precursor are as follows: specific surface area is 8.97m 2 / g, tap density is 1.89g / m 3 , porosity is 6.85%, and D50 is 4.01um.

[0052] The difference between Example 2 and Example 1 is that protective gas N2 is introduced during the entire nucleation and growth stage.

[0053] Figure 4 This is a cross-sectional electron micrograph of the precursor prepared in Example 2. From the cross-sectional electron micrograph, it can be seen that the inner core presents a clear porous structure, but the hollow large core structure is not obvious enough.

[0054] Embodiment 3:

[0055] Ni in a molar ratio of 0.92:0.04:0.04 2+ 、Co 2+ , Mn 2+ Add salt to pure water, stir for 15-30 minutes until it is evenly mixed, prepare ammonia water concentration of 20%, alkali solution concentration of 32%, respectively, and filter them through precision filters to remove tiny solid particles in the liquid to ensure the impurity content. 3 Stainless steel reactor, 3m 3 Stainless steel concentrator. Fill the reactor and concentrator with pure water in advance and circulate it, raise the reactor temperature to 65℃, control the frequency of the agitator inverter at 45±1Hz, adjust the ammonia value in the reactor to 6.0~6.5g / L, and the residual alkali value to 3.1-3.3g / L. During the adjustment process, the reactor and concentrator continue to circulate, and continue to circulate for 20~30min after adjusting to the established parameter value as the base liquid. This process is carried out in an inert atmosphere. After reaching the set requirements, the metal salt mixed solution is added to the reactor with the prepared base liquid through the material pipe②, liquid alkali, and ammonia water through the corresponding feed pipes. In the first 10h, the mixed metal salt addition rate is controlled at 300.0±5.0L / h, and the ammonia value is maintained at 6.0~6.5g / L and the residual alkali is 3.1-3.3g / L, until the nucleation particle size D50=1.5um. Start to introduce N2, keep feeding the metal salt into the feed pipe ②, keep the position of ammonia and alkali unchanged, and increase gradually from 400.0±5.0L / h within 10-20h to 450.0±5.0L / h within 20-30h, and to 500.0±5.0L / h after 30h. According to the flow rate of the mixed metal salt, the flow rate of ammonia water and liquid alkali is adjusted, the ammonia value is controlled at 6.0-6.5g / L, the residual alkali is gradually reduced, and the residual alkali is reduced by 0.01-0.1g / L every 1h of reaction after 10h, until the residual alkali is below 0.6g / L; the process controls the discharge of the concentrator according to the feed flow of the reactor, so that the discharge of the mother liquor of the concentrator and the feed of the reactor are kept in dynamic balance, the average reaction concentration time is controlled between 75-85h, the particle size D50 of the material in the reactor reaches the controlled particle size D50=3.0-5.0um, the feed is stopped, and the materials in the reactor and the concentrator are pumped into the aging reactor for 30-60min. The materials after post-aging are sequentially washed with alkali at a concentration of 0.50-0.90mol / L and a temperature of 70-85℃, and washed with pure water at a temperature of 70-85℃ for 60-200min. Subsequently, the above materials are dried in a tray dryer with an upper tray temperature of 120-140° C. and middle and lower tray temperatures of 110-130° C. to obtain a single-crystal porous large core structure ternary precursor.

[0056] The physical and chemical parameters of the precursor obtained are: specific surface area is 10.73m 2 / g, tap density is 2.04g / m 3, the porosity is 2.07% and D50 is 3.61um.

[0057] The difference between Example 3 and Example 1 is that the feeding is maintained through the feeding pipe ② during the nucleation and growth stages.

[0058] Figure 5 This is a cross-sectional electron micrograph of the precursor prepared in Example 3. From the cross-sectional electron micrograph, it can be seen that the particles have good sphericity and the loose hollow large core structure has basically disappeared.

[0059] Embodiment 4:

[0060] Ni in a molar ratio of 0.92:0.04:0.04 2+ 、Co 2+ , Mn 2+ Add salt to pure water, stir for 15-30 minutes until it is evenly mixed, prepare ammonia water concentration of 20%, alkali solution concentration of 32%, respectively, and filter them through precision filters to remove tiny solid particles in the liquid to ensure the impurity content. 3 Stainless steel reactor, 3m 3Stainless steel concentrator. Fill the reactor and concentrator with pure water in advance and circulate it, raise the reactor temperature to 65℃, control the frequency of the agitator inverter at 45±1Hz, adjust the ammonia value in the reactor to 5.0~5.5g / L, and the residual alkali value to 3.1-3.3g / L. During the adjustment process, the reactor and concentrator continue to circulate, and continue to circulate for 20~30min after adjusting to the established parameter value, and then use it as the base liquid in N2 atmosphere. After reaching the set requirements, add the metal salt mixed solution through the material pipe②, liquid alkali, and ammonia water through the corresponding feed pipes to the reactor with the prepared base liquid. In the first 10h, control the addition rate of the mixed metal salt to 300.0±5.0L / h, maintain the ammonia value at 5.0~5.5g / L, and the residual alkali at 3.1-3.3g / L, until the nucleation particle size D50=1.5um. Keep N2 flowing and metal salt feeding through pipe ②, the position of ammonia and alkali remain unchanged, and increase gradually from 400.0±5.0L / h within 10-20h to 450.0±5.0L / h within 20-30h, and to 500.0±5.0L / h after 30h. According to the flow rate of the mixed metal salt, the flow rate of ammonia water and liquid alkali is adjusted, the ammonia value is controlled at 6.0-6.5g / L, the residual alkali is gradually reduced, and the residual alkali is reduced by 0.01-0.1g / L every 1h of reaction after 10h, until the residual alkali is below 0.6g / L; the process controls the discharge of the concentrator according to the feed flow of the reactor, so that the discharge of the mother liquor of the concentrator and the feed of the reactor are kept in dynamic balance, the average reaction concentration time is controlled between 75-85h, the particle size D50 of the material in the reactor reaches the controlled particle size D50=3.0-5.0um, the feed is stopped, and the materials in the reactor and the concentrator are pumped into the aging reactor for 30-60min. The materials after post-aging are sequentially washed with alkali at a concentration of 0.50-0.90mol / L and a temperature of 70-85℃, and washed with pure water at a temperature of 70-85℃ for 60-200min. Subsequently, the above materials are dried in a tray dryer with an upper tray temperature of 120-140° C. and middle and lower tray temperatures of 110-130° C. to obtain a single-crystal porous large core structure ternary precursor.

[0061] The physicochemical parameters of the precursor obtained are: specific surface area of ​​9.37m 2 / g, tap density is 1.92g / m 3 , the porosity is 4.74% and D50 is 3.91um.

[0062] The difference between Example 4 and Example 3 is that the entire process of nucleation and growth is carried out in an atmosphere of N2 gas.

[0063] Figure 6 , Figure 7They are cross-sectional electron micrographs and SEM electron micrographs of the precursor prepared in Example 4. From the SEM electron micrograph, it can be seen that the dispersion is good, and under the cross-sectional electron micrograph, it can be clearly observed that the inner core presents a clear porous structure, but the hollow large core structure is not obvious.

[0064] Embodiment 5:

[0065] In Example 5, the nucleation and growth stages are still fed through feed pipe ①, and other conditions remain the same as in Example 4.

[0066] The physical and chemical parameters of the obtained precursor are as follows: the specific surface area is 9.24m 2 / g, tap density is 1.84g / m 3 , D50 is 4.11um.

[0067] Figure 8 This is a SEM electron microscope image of the precursor prepared in Example 5. From the SEM electron microscope, it can be seen that agglomeration occurs between particles and the dispersion is poor.

[0068] The above description is only a preferred implementation of the present invention. Any improvements and modifications made by those skilled in the art without departing from the principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor, characterized in that The following steps are involved: (1) preparing a mixed solution of metal salts of Ni, Co and Mn, a complexing agent solution and a precipitant solution; (2) finely filtering the solutions prepared in step (1) to remove tiny solid particles in the solutions; (3) Connecting the reactor and the concentrator in series and adding pure water for circulation, adjusting the reactor temperature, stirring frequency, ammonia value, and alkalinity to the target values ​​as the base liquid; (4) passing the filtered metal salt mixed solution through a feed pipe located above the outer edge of the middle stirring blade, and at the same time, adding the precipitant solution and the complexing agent solution into the reaction system through corresponding feed pipes to perform a precipitation reaction and nucleate to a target nucleation particle size; (5) Subsequently, an inert gas is introduced into the reaction system, and at the same time, the metal salt mixed solution is adjusted to be added to the reactor from the feed pipe near the upper outer edge of the lower stirring blade. The feeding method of the precipitant solution and the complexing agent solution remains unchanged, and the material mixing method in the reactor is changed to continue the concentration coprecipitation reaction to the target particle size; the residual alkali is controlled to reduce by 0.02 to 0.1 g / L every 1 hour of reaction until the residual alkali is reduced to less than 0.6 g / L; (6) After reaching the target particle size, stop feeding and perform post-processing to obtain a single crystal porous large core NCM high nickel ternary precursor.

2. A method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that The component ratio of the metal salt mixed solution described in step (1) is Ni 2+ : Co 2+ : Mn 2+ meeting the requirement: Ni x Co y Mn z (OH)2, where x + y + z = 1, 0.8 ≤ x < 1, 0 < y < 0.2, 0 < z < 0.2, and the total metal ion concentration is preferably 1.5 - 2.0 mol / L.

3. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that The complexing agent solution in step (1) is ammonia water with a concentration of 15% to 20%, and the precipitating agent solution is liquid alkali with a concentration of 26% to 32%.

4. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that The precision filtration in step (2) is carried out by filtering through a microporous precision filter with a filtration accuracy of 0.5 μm.

5. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that In step (3), the kettle temperature is controlled at 60-70° C., the frequency of the frequency converter of the stirring blade is controlled at 45±1 Hz, the bottom liquid ammonia value is controlled at 6.0-6.5 g / L, and the residual alkali is controlled at 3.1-3.3 g / L.

6. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that In step (4), the feeding position is close to 70 mm above the outer edge of the middle blade, the residual alkali is controlled to be 3.1-3.3 g / L, and the metal salt mixed solution is added at a rate of 300.0±5.0 L / h until the particle size grows to the target nucleation particle size D50 of 1.3-1.6 μm, and the reaction time is 10 h.

7. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 6, characterized in that In step (5), based on step (4), the feed position is adjusted to 50 mm above the outer edge of the lower stirring blade, and the flow rate of the metal salt mixed solution is adjusted according to the reaction time, and is adjusted to 400.0±5.0 L / h within 10 to 20 hours of reaction, to 450.0±5.0 L / h within 20 to 30 hours, and to 500.0±5.0 L / h after 30 hours. The average reaction concentration time is controlled between 75 and 85 hours, and the target particle size D50 median is 3.5 μm.

8. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that The kettle temperature, stirring, and ammonia value of step (4) and step (5) are consistent with the conditions of step (3).

9. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that In step (5), the inert gas is at least one of nitrogen, helium and argon.

10. The method for preparing a high-performance single-crystal porous large-core NCM high-nickel ternary precursor according to claim 1, characterized in that The post-treatment in step (6) includes aging, washing, drying, screening and iron removal. The aging time is 30 to 60 minutes. The aged material is washed with alkali and then with water. The alkali concentration is 0.50 to 0.90 mol / L, the temperature is 70 to 85° C., and the water temperature is 70 to 85° C. The washed material is dried in a disk dryer. The temperature of the upper disk of the disk dryer is 120 to 140° C., and the middle and lower disks are controlled at 110 to 130° C. respectively.

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