A high-nickel ternary precursor with a tight inner structure and a loose outer structure and its preparation method

Abstract

This invention belongs to the field of lithium-ion battery cathode material technology, and relates to a high-nickel ternary precursor with a compact inner core and a loose outer core, and its preparation method. The method includes: 1) introducing a nickel-cobalt-manganese ternary mixed solution, a complexing agent, and a precipitant into a first reaction vessel for co-deposition to prepare a compact nickel-cobalt-manganese core structure; 2) after washing the core, quantitatively introducing it again into a second reaction vessel and introducing the nickel-cobalt-manganese ternary mixed solution, complexing agent, precipitant, and inorganic alkaline aluminum solution to prepare an aluminum-containing nickel-cobalt-manganese outer core structure; 3) after the overall particle size reaches the target particle size, placing the reacted material in a strong alkaline solution and stirring to dissolve the aluminum hydroxide in the outer core, forming a loose structure, thus obtaining the high-nickel ternary precursor with a compact inner core and a loose outer core. The precursor prepared by this invention has good microstructural stability and rate performance, and can be industrialized without the need for additional equipment based on existing industrial production equipment, showing broad prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery cathode material technology, and in particular to a method for preparing a high-nickel ternary precursor with a tight inner structure and a loose outer structure by a leaching method. Background Technology

[0002] In the field of lithium-ion battery cathode materials, the theoretical energy density of high-nickel NCM ternary cathode materials can reach 600 Wh / g. However, while increasing the nickel content in ternary cathode materials can improve energy density, reducing cobalt content leads to a decrease in rate performance, and reducing manganese content results in decreased structural stability and accelerated cycle life decay. Therefore, other design methods must be used to compensate for the inherent disadvantages of high-nickel ternary cathode materials.

[0003] Currently, industrialized ternary cathode materials are all prepared by solid-state sintering of ternary precursors and lithium salts. The particle size and internal pore structure of ternary cathode materials have good inheritance from ternary precursors. Therefore, the structural design of ternary precursors plays a decisive role in the electrochemical performance of ternary cathode materials.

[0004] Designing a high-nickel ternary cathode material that leverages its high specific capacity while also possessing excellent rate performance and cycle stability is of great significance. In the field of low-nickel ternary precursors, the internal structure of ternary precursor particles is generally a dense structure with few pores. Cathode materials prepared from these ternary precursor particles have a single lithium-ion diffusion path, high diffusion resistance, and insufficient rate performance. Furthermore, batteries have consistently faced the problem of unstable particle structure strength due to repeated charging and discharging, leading to cracking within the particle cells, resulting in shorter lifespan, lower capacity, and poor safety performance during use. With increasing nickel content, high-nickel ternary precursors have gradually shifted from continuous processes to batch concentration processes to improve particle consistency. However, the increased stress accumulation from higher nickel and reactant solids content, along with larger particle size, leads to a greater risk of particle breakage in high-nickel precursors, and the decrease in cobalt content results in insufficient rate performance. If a compact structure is formed at the center of the ternary cathode material, while a loose, porous, and well-radiating structure is formed on the outside, the structural damage caused by material volume changes and side reactions can be effectively mitigated. Furthermore, the loose, porous, radial structure can create more lithium-ion migration channels, accelerating the ion migration rate and effectively reducing electrochemical polarization, resulting in better rate performance. Therefore, it is essential to prepare high-nickel ternary precursors with a compact inner structure and a loose outer structure. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and provide a high-nickel ternary precursor with a compact inner core and a loose outer core, as well as its preparation method. In the preparation process of the high-nickel ternary precursor, during the core-particle reaction growth, process adjustments are made to ensure tight packing of primary particles, forming a dense core structure to enhance the mechanical strength of the material. During the outer core-particle reaction growth, an inorganic aluminum alkali solution is introduced in addition to the nickel-cobalt-manganese raw materials to inhibit the growth of primary particles, thereby obtaining smaller-sized primary particles. The reacted material is then immersed in a strong alkali solution to dissolve the generated aluminum hydroxide, resulting in a porous and loose outer core structure, thus obtaining a high-nickel ternary precursor with a compact inner core and a loose outer core. This enhances the microstructural stability of the material while improving its rate performance. The first objective of this invention is to provide a high-nickel ternary precursor with a compact inner core and a loose outer core. The second objective of this invention is to provide a method for preparing such a precursor.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows:

[0007] This invention provides a method for preparing a high-nickel ternary precursor with an internally compact and externally loose structure, comprising the following steps:

[0008] (1) Prepare a ternary mixed metal salt solution using nickel, cobalt, and manganese inorganic salts; prepare an inorganic aluminum alkali solution; prepare an aqueous precipitant solution; prepare an aqueous complexing agent solution;

[0009] (2) Fill the first reactor and the first concentrator with pure water and circulate it, and introduce protective gas, and introduce complexing agent aqueous solution and precipitant aqueous solution to adjust the complexing agent concentration and the first pH, and control the reaction temperature;

[0010] Under the first stirring speed condition, the ternary mixed metal salt solution, the complexing agent aqueous solution and the precipitant aqueous solution are simultaneously introduced into the reaction vessel, and the reaction pH is controlled to maintain the first pH.

[0011] Once the particle size of the reactants reaches the target particle size of the core, the flow of the ternary mixed metal salt solution, complexing agent aqueous solution, and precipitant aqueous solution is stopped. The reacted core slurry is then pumped into a centrifuge, washed and dried to obtain the core filter cake for later use.

[0012] (3) Fill the second reactor and the second concentrator with pure water and circulate it, and introduce protective gas, and introduce complexing agent aqueous solution and precipitant aqueous solution to adjust the complexing agent concentration and the second pH, control the reaction temperature, and add a certain amount of core filter cake.

[0013] Under the second stirring speed condition, the ternary mixed metal salt solution, complexing agent aqueous solution, precipitant aqueous solution and inorganic aluminum alkali solution are simultaneously introduced into the reactor, the reaction pH is controlled to maintain the second pH, and the reaction stirring speed is stepped down from the second stirring speed to the third stirring speed.

[0014] The reaction is stopped once the particle size of the reactants reaches the overall target particle size.

[0015] (4) After the reaction, the material is transferred to an aging kettle and left to stand. The supernatant is removed, and a strong alkaline solution is added and stirred to dissolve the aluminum hydroxide in the outer core to form a porous and loose structure. After post-treatment, a high-nickel ternary precursor with a tight inner core and a loose outer core is obtained.

[0016] Preferably, in step (1), the nickel, cobalt, and manganese inorganic salts are one or more of the corresponding sulfates, nitrates, and chlorides; more preferably, the nickel inorganic salt is one or more of nickel sulfate, nickel nitrate, and nickel chloride, the cobalt inorganic salt is one or more of cobalt sulfate, cobalt nitrate, and cobalt chloride, and the manganese inorganic salt is one or more of manganese sulfate, manganese nitrate, and manganese chloride.

[0017] Preferably, the total concentration of metals (nickel, cobalt, manganese) in the ternary mixed metal salt solution in step (1) is 1.0 to 2.3 mol / L.

[0018] Preferably, in step (1), the nickel-cobalt-manganese ratio in the ternary mixed metal salt solution conforms to the formula Ni x Co y Mn (1-x-y) (OH)2, where 0 <x<0.98,0<y<0.40。

[0019] Preferably, the inorganic aluminum in the inorganic aluminum alkali solution in step (1) is one or more of sodium aluminate and aluminum sulfate; more preferably, the aluminum concentration in the inorganic aluminum alkali solution in step (1) is 0.10 to 1.0 mol / L, the alkali is one or more of sodium hydroxide and potassium hydroxide, and the pH value of the inorganic aluminum alkali solution is adjusted to 13.00 to 13.50.

[0020] Preferably, the precipitant in step (1) is one or more of sodium hydroxide and potassium hydroxide. More preferably, the concentration of the aqueous solution of the precipitant in step (1) is 5.0–12.0 mol / L.

[0021] Preferably, the complexing agent in step (1) is one or more of ammonia, ammonium sulfate, sodium ascorbate, salicylic acid, and oxalic acid. More preferably, the concentration of the aqueous solution of the complexing agent in step (1) is 1.0–11.0 g / L.

[0022] Preferably, the volume of the first reaction vessel in step (2) is 1-10 m³. 3 More preferably, the volume of the first concentrator in step (2) is 0.1–3 m³. 3 .

[0023] Preferably, the protective gas in step (2) is one or more of nitrogen or helium.

[0024] Preferably, in step (2), the reaction temperature is 45–70°C; the concentration of the complexing agent is 0.5–10.0 g / L; the first pH of the reaction is 10.30–11.00; the first stirring speed is 200–540 rpm; the pump flow rate of the ternary mixed metal salt solution is 30–600 L / h; and the core target particle size is 3.0–7.0 μm.

[0025] Preferably, the centrifuge washing time in step (2) is 200-800s; the centrifuge washing temperature is 60-75℃.

[0026] Preferably, the moisture content of the kernel filter cake in step (2) is 10-25%.

[0027] Preferably, the volume of the second reactor in step (3) is 1-10 m³. 3 More preferably, the volume of the second concentrator in step (3) is 0.1–3 m³. 3 .

[0028] Preferably, the protective gas in step (3) is one or more of nitrogen or helium.

[0029] Preferably, in step (3), the reaction temperature is 45–70°C; the concentration of the complexing agent is 0.5–10.0 g / L; the second pH of the reaction is 10.00–11.20; the second stirring speed is 150–300 rpm; the pump flow rate of the ternary mixed metal salt solution is 30–600 L / h; the pump flow rate of the inorganic aluminum alkali solution is 2–100 L / h; the third stirring speed is 30–100 rpm; and the overall target particle size is 8–18 μm.

[0030] Preferably, the weight of the kernel filter cake added in step (3) is [(aV / D 3 *d 3 ) / (1-s)]kg;

[0031] Where a is a constant, and its value ranges from 200 to 800;

[0032] V is the volume of the second reactor, in cubic meters (m³). 3 ;

[0033] D represents the overall target particle size, in μm;

[0034] d represents the kernel target particle size, in μm;

[0035] s represents the moisture content of the filter cake, expressed as a percentage.

[0036] Preferably, in step (3), the stirring speed is decreased by 20 rpm per hour in a stepwise manner. A high stirring speed in the early stages of the reaction can prevent particle adhesion and the formation of twinned particles. As the particle size increases and the solid content of the reaction system increases, the risk of adhesion decreases, but the risk of ball cracking increases. Decreasing the stirring speed can reduce the increase in internal stress within the particles, which can lead to ball cracking.

[0037] Preferably, in step (3), the second stirring speed is not greater than the first stirring speed, and the second pH is not greater than the first pH.

[0038] Preferably, the settling time in step (4) is 2 to 4 hours.

[0039] Preferably, the strong alkali added in step (4) is at least one of sodium hydroxide and potassium hydroxide; more preferably, the mass concentration of the strong alkali solution is 32%, and the added volume is 0.5-5 ml. 3 More preferably, the stirring time in step (4) is 10 to 24 hours.

[0040] Preferably, the post-processing includes washing, centrifuging, drying, batch mixing, sieving, and iron removal of the leached material to obtain a high-nickel precursor with a tight inner structure and loose outer structure;

[0041] More preferably, the washing temperature is 60–75°C;

[0042] More preferably, the drying temperature is 100–150°C.

[0043] Preferably, the compact internal structure size of the ternary precursor obtained by the preparation method is 3–7 μm; more preferably, the overall particle size of the ternary precursor is 8.0–18.0 μm, and the particle size distribution is 0.2–0.45; even more preferably, the tap density of the ternary precursor is 1.8–2.3 g / cm³. 3 More preferably, the ternary precursor BET is 8–20 m. 2 / g.

[0044] The present invention also provides a ternary precursor with an internally compact and externally loose structure prepared by any of the above-described preparation methods. The precursor has an internal compact structure with a size of 3–7 μm, a particle size of 8.0–18.0 μm, a particle size distribution of 0.2–0.45, and a tap density of 1.8–2.3 g / cm³. 3 BET is 8-20m 2 / g.

[0045] This invention utilizes a process design to co-deposit a tightly packed nickel-cobalt-manganese core structure in a reactor, comprising a nickel-cobalt-manganese ternary mixed solution, a complexing agent, and a precipitant. Once the core particle size reaches the target size, the reaction is stopped, and the core particles are washed and separated. The core particles are then used as seed crystals for further reaction. The reactor is then filled with a nickel-cobalt-manganese ternary mixed solution, an inorganic aluminum alkaline solution, a complexing agent, and a precipitant to co-deposit an aluminum-containing nickel-cobalt-manganese outer core structure. The addition of aluminum inhibits the growth of the primary particles, resulting in smaller primary particle sizes. After the overall particle size reaches the target size, the reacted material is placed in a strong alkaline solution and stirred to dissolve the aluminum hydroxide in the core, forming a porous and loose outer core structure. This yields a high-nickel ternary precursor with a tight inner structure and a loose outer structure, enhancing the material's microstructural stability and improving its rate performance.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] In the technical solution described in this invention, aluminum is used as an amphoteric metal. Aluminate or aluminum ions are used as the aluminum source, and a nickel-cobalt-manganese aluminum hydroxide core is prepared under weakly alkaline conditions via a co-deposition reaction and nickel-cobalt-manganese metal ions. Aluminum hydroxide is uniformly distributed within the core, simultaneously inhibiting the growth of primary particles, thereby obtaining smaller primary particle morphologies. After co-deposition, the prepared particles are stirred in a strongly alkaline environment to dissolve and release the aluminum hydroxide from the core, forming a porous and loose core structure.

[0048] In the technical solution described in this invention, the core size can be precisely controlled by the reaction time, the number of seed crystals can be precisely controlled by washing and weighing the core material again, the growth rate of the outer core can be effectively controlled, and the growth ratio of aluminum hydroxide in the outer core can be precisely controlled by controlling the pumping rate of the alkaline aluminum solution, thereby controlling the porosity of the outer core.

[0049] Compared with existing ternary precursor preparation technologies, the technology described in this invention can achieve quantitative control of the inner and outer core sizes and porosity. It can be industrialized without the need for additional equipment based on existing industrial equipment, and has broad prospects for industrial application. Attached Figure Description

[0050] Figure 1-1 , Figure 1-2 Scanning electron microscope image of the internally compact and externally loose high-nickel ternary precursor prepared by the dissolution method in Example 1;

[0051] Figure 2-1 , Figure 2-2 Scanning electron microscope image of the high-nickel ternary precursor with a tight inner structure and loose outer structure prepared by the dissolution method in Example 2;

[0052] Figure 3-1 , Figure 3-2SEM image of the inner-dense and outer-loose type high-nickel ternary precursor prepared by the dissolution method in Example 3;

[0053] Figure 4-1 、 Figure 4-2 SEM image of the high-nickel ternary precursor prepared in Comparative Example 1.

[0054] Figure 5-1 、 Figure 5-2 SEM image of the high-nickel ternary precursor prepared in Comparative Example 2. Detailed implementation manners

[0055] The technical solutions of the present invention will be further specifically described below through specific examples and in combination with the accompanying drawings. Obviously, the following examples are only partial examples of the present invention, not all examples. It should be noted that all examples made by those skilled in the art without departing from the main concept of the present invention and making non-essential changes still fall within the protection scope of the present invention.

[0056] In the examples of the present invention, the experimental methods and conditions used are conventional methods and conventional conditions unless otherwise specified. The materials, reagents or instruments used in the examples can be obtained from commercial sources or prepared by conventional methods unless otherwise specified. The reaction conditions reflected in the content of the present invention can all achieve the described reaction and obtain the products with expected effects. Due to space limitations, some examples are listed below to further illustrate the advantages of the technical solutions of the present invention.

[0057] The present invention provides an inner-dense and outer-loose type high-nickel ternary precursor prepared by a dissolution method and its preparation method. The steps of the preparation method are as follows:

[0058] Prepare a ternary mixed metal salt solution with a molar ratio of Ni x Co y Mn (1-x-y) (OH)2, 0 < x < 0.98, 0 < y < 0.40, and the total concentration of metal (nickel, cobalt, manganese) is 1.0 - 2.3 mol / L; prepare an inorganic aluminum alkali solution with an aluminum concentration of 0.10 - 1.0 mol / L by using an inorganic aluminum salt, and adjust the pH value of the solution to 13.00 - 13.50 with sodium hydroxide; prepare an aqueous solution of a precipitating agent with a concentration of 5.0 - 12.0 mol / L; prepare an aqueous solution of a complexing agent with a concentration of 1.0 - 11.0 g / L;

[0059] In a first reaction kettle with a volume of 1 - 10 m 3 and a second reaction kettle with a volume of 0.1 - 3 m 3The concentrator is filled with pure water and circulated, and a protective gas is introduced. A complexing agent aqueous solution and a precipitant aqueous solution are introduced to adjust the complexing agent concentration to 0.5-10.0 g / L and the first pH to 10.30-11.00, and the reaction temperature is controlled at 45-70℃. Under the condition of a first stirring speed of 200-540 rpm, a ternary mixed metal salt solution is pumped into the reactor at a flow rate of 30-600 L / h. At the same time, the complexing agent aqueous solution and the precipitant aqueous solution are simultaneously introduced into the reactor. The reaction pH is controlled to maintain a first pH of 10.30-11.00, and the concentration of the complexing agent is 0.5-10.0 g / L. When the particle size of the reactants reaches the target particle size of the core of 3.0-7.0 μm, the introduction of the ternary mixed metal salt solution, complexing agent aqueous solution, and precipitant aqueous solution is stopped. The reacted core slurry is pumped into a centrifuge for washing with water for 200-800 seconds at a temperature of 60-75°C. The core filter cake is then dried until the moisture content of the filter cake is 10-25% for later use.

[0060] In volumes of 1–10 m³ 3 The second reaction vessel has a volume of 0.1–3 m³. 3 The concentrator is filled with pure water and circulated, and a protective gas is introduced. A complexing agent aqueous solution and a precipitant aqueous solution are then introduced to adjust the complexing agent concentration to 0.5–10.0 g / L and the second pH to 10.00–11.20, while controlling the reaction temperature at 45–70°C. A weight of [(aV / D] is added. 3 *d 3 The core filter cake was 1 kg / (1-s). Under a second stirring speed of 150–300 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 30–600 L / h. Simultaneously, an aqueous solution of the complexing agent, an aqueous solution of the precipitant, and an inorganic aluminum alkali solution were introduced into the reactor. The flow rate of the inorganic aluminum alkali solution was controlled at 2–100 L / h. The reaction pH was maintained at a second pH of 10.00–11.20, and the concentration of the complexing agent was 0.5–10.0 g / L. The stirring speed was gradually reduced by 20 rpm per hour from the second stirring speed to a third stirring speed of 30–100 rpm. The reaction was stopped when the overall particle size of the reactants reached the target particle size of 8–18 μm.

[0061] After the reaction, the material is transferred to an aging reactor and allowed to stand for 2-4 hours. The supernatant is then removed, and 0.5-5 ml of a 32% strong alkali solution is added. 3 The material is stirred for 10–24 hours to dissolve aluminum hydroxide in the outer core, forming a porous and loose structure. After washing and centrifugation at 60–75°C, drying at 100–150°C, batch mixing, sieving, and iron removal, a high-nickel ternary precursor with a compact inner structure and a loose outer structure is obtained. The precursor has a compact internal structure with a size of 3–7 μm, a particle size of 8.0–18.0 μm, a particle size distribution of 0.2–0.45, and a tap density of 1.8–2.3 g / cm³.3 BET is 8-20m 2 / g.

[0062] Example 1

[0063] A nickel, cobalt, and manganese inorganic salt with a molar ratio of Ni was prepared. 0.88 Co 0.09 Mn 0.03 A ternary mixed metal salt solution with a total metal (nickel, cobalt, manganese) concentration of 2.0 mol / L was prepared using (OH)2; an inorganic aluminum alkali solution with an aluminum concentration of 0.20 mol / L was prepared using sodium aluminate, and the pH of the solution was adjusted to 13.20 using sodium hydroxide; a sodium hydroxide aqueous solution with a concentration of 10 mol / L was prepared; and an ammonia aqueous solution with a concentration of 8.0 g / L was prepared.

[0064] In a volume of 1m 3 The first reaction vessel has a volume of 0.2 m³. 3 The concentrator is filled with pure water and circulated, with nitrogen gas introduced for protection. A complexing agent aqueous solution and a precipitant aqueous solution are introduced to adjust the complexing agent concentration to 3.8 g / L and the initial pH to 10.80, while controlling the reaction temperature at 60°C. Under a first stirring speed of 480 rpm, a ternary mixed metal salt solution is pumped into the reactor at a flow rate of 30 L / h, simultaneously with the complexing agent aqueous solution and the precipitant aqueous solution, maintaining the initial pH at 10.80. Once the reactant particle size reaches the target core particle size of 4.0 μm, the introduction of the ternary mixed metal salt solution, complexing agent aqueous solution, and precipitant aqueous solution is stopped. The resulting core slurry is pumped into a centrifuge for washing with water for 300 s at a temperature of 70°C. The core filter cake is then dried until its moisture content is 15% for later use.

[0065] In a volume of 1m 3 The second reaction vessel has a volume of 0.2 m³. 3 The concentrator was filled with pure water and circulated, with nitrogen gas introduced as a protective gas. Complexing agent aqueous solution and precipitant aqueous solution were introduced to adjust the complexing agent concentration to 3.8 g / L and the second pH to 11.00, while controlling the reaction temperature at 60℃. A 17.5 kg core filter cake was added. Under a second stirring speed of 300 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 50 L / h. Simultaneously, the complexing agent aqueous solution, precipitant aqueous solution, and inorganic aluminum alkali solution were introduced into the reactor, with the inorganic aluminum alkali solution pumped at a flow rate of 5 L / h. The reaction pH was maintained at the second pH of 11.00. The stirring speed was gradually reduced by 20 rpm per hour, from the second stirring speed to a third stirring speed of 80 rpm. The reaction was stopped when the overall particle size of the reactants reached the target particle size of 12 μm.

[0066] After the reaction, the material was transferred to an aging reactor and allowed to stand for 3 hours. The supernatant was then removed, and 1 ml of a 32% strong alkali solution was added. 3 Stirring for 12 hours causes aluminum hydroxide in the outer core to dissolve and form a porous, loose structure. The material is then washed with water at 70°C, centrifuged, dried at 130°C, mixed, sieved, and iron removed to obtain a high-nickel ternary precursor with a tight inner core and loose outer core.

[0067] The ternary precursor material prepared in Example 1 of this invention was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 1-1 , Figure 1-2 As shown, the ternary precursor material prepared in Example 1 of this invention has a compact structure of 3.86 micrometers in the center and a loose porous structure in the outer core.

[0068] The D50 of the high-nickel ternary precursor with a tight inner structure and loose outer structure prepared in Example 1 of this invention is 12.21 μm.

[0069] The high-nickel ternary precursor with a compact inner structure and loose outer structure prepared in Example 1 of this invention has a particle size distribution of 0.42.

[0070] The tap density of the high-nickel ternary precursor with a tight inner structure and loose outer structure prepared in Example 1 of this invention is 1.94 g / cm³. 3 .

[0071] The BET of the high-nickel ternary precursor with a tight inner structure and loose outer structure prepared in Example 1 of this invention is 12.68m. 2 / g.

[0072] Example 2

[0073] A nickel, cobalt, and manganese inorganic salt with a molar ratio of Ni was prepared. 0.90 Co 0.05 Mn 0.05 A ternary mixed metal salt solution with a total metal (nickel, cobalt, manganese) concentration of 2.2 mol / L was prepared using (OH)2; an inorganic aluminum alkali solution with an aluminum concentration of 0.50 mol / L was prepared using sodium aluminate, and the pH of the solution was adjusted to 13.00 using sodium hydroxide; a sodium hydroxide aqueous solution with a concentration of 5 mol / L was prepared; and an ammonia aqueous solution with a concentration of 8.0 g / L was prepared.

[0074] In a volume of 10m 3 The first reaction vessel has a volume of 2m³. 3The concentrator is filled with pure water and circulated, with nitrogen gas introduced for protection. Complexing agent and precipitant solutions are introduced to adjust the complexing agent concentration to 4.5 g / L and the initial pH to 10.70, while controlling the reaction temperature at 55°C. Under a first stirring speed of 250 rpm, a ternary mixed metal salt solution is pumped into the reactor at a flow rate of 400 L / h, simultaneously with the complexing agent and precipitant solutions, maintaining the initial pH at 10.70. Once the reactant particle size reaches the target core particle size of 6.50 μm, the introduction of the ternary mixed metal salt solution, complexing agent solution, and precipitant solution is stopped. The resulting core slurry is pumped into a centrifuge for washing with water for 300 s at 70°C. The core filter cake is then dried until its moisture content is 12% for later use.

[0075] In a volume of 10m 3 The second reaction vessel has a volume of 2m³. 3 The concentrator was filled with pure water and circulated, with nitrogen gas introduced as a protective gas. Complexing agent aqueous solution and precipitant aqueous solution were introduced to adjust the complexing agent concentration to 4.5 g / L and the second pH to 10.50, while controlling the reaction temperature at 55℃. A core filter cake weighing 568 kg was added. Under a second stirring speed of 160 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 550 L / h. Simultaneously, the complexing agent aqueous solution, precipitant aqueous solution, and inorganic aluminum alkali solution were introduced into the reactor, with the inorganic aluminum alkali solution pumped at a flow rate of 22 L / h. The reaction pH was maintained at the second pH of 10.50. The stirring speed was gradually reduced by 20 rpm per hour, from the second stirring speed to a third stirring speed of 40 rpm. The reaction was stopped when the overall particle size of the reactants reached the target particle size of 14 μm.

[0076] After the reaction, the material was transferred to an aging reactor and allowed to stand for 2 hours. The supernatant was then removed, and 4 ml of a 32% sodium hydroxide solution was added. 3 The mixture was stirred for 15 hours to allow aluminum hydroxide in the outer core to dissolve, forming a porous and loose structure. The material was then washed with water at 70℃, centrifuged, dried at 130℃, mixed in batches, sieved, and iron removed to obtain a high-nickel ternary precursor with a compact inner structure and a loose outer structure. The precursor had a compact internal structure size of 6.54 μm, a particle size D50 of 14.12 μm, a particle size distribution of 0.31, and a tap density of 2.01 g / cm³. 3 BET is 17.82m 2 / g.

[0077] The ternary precursor material prepared in Example 2 of this invention was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 2-1 , Figure 2-2 As shown, the ternary precursor material prepared in Example 2 of this invention has a compact structure of 6.54 micrometers in the center and a loose porous structure in the outer core.

[0078] Example 3

[0079] A nickel, cobalt, and manganese inorganic salt with a molar ratio of Ni was prepared. 0.95 Co 0.03 Mn 0.02 A ternary mixed metal salt solution with a total metal (nickel, cobalt, manganese) concentration of 1.60 mol / L was prepared using (OH)2; an inorganic aluminum alkali solution with an aluminum concentration of 0.50 mol / L was prepared using sodium aluminate, and the pH of the solution was adjusted to 13.20 using sodium hydroxide; a sodium hydroxide aqueous solution with a concentration of 5 mol / L was prepared; and an ammonia aqueous solution with a concentration of 8.0 g / L was prepared.

[0080] In a volume of 8m 3 The first reaction vessel has a volume of 2m³. 3 The concentrator is filled with pure water and circulated, with nitrogen gas introduced for protection. A complexing agent aqueous solution and a precipitant aqueous solution are introduced to adjust the complexing agent concentration to 2.2 g / L and the initial pH to 11.20, while controlling the reaction temperature at 60℃. Under a first stirring speed of 420 rpm, a ternary mixed metal salt solution is pumped into the reactor at a flow rate of 200 L / h, simultaneously with the complexing agent aqueous solution and the precipitant aqueous solution, maintaining the initial pH at 11.20. When the reactant particle size reaches the target core particle size of 5.5 μm, the introduction of the ternary mixed metal salt solution, complexing agent aqueous solution, and precipitant aqueous solution is stopped. The resulting core slurry is pumped into a centrifuge for washing with water for 300 s at a temperature of 70℃. The core filter cake is then dried until its moisture content is 18% for later use.

[0081] In a volume of 8m 3 The second reaction vessel has a volume of 2m³. 3 The concentrator was filled with pure water and circulated, with nitrogen gas introduced as a protective gas. Complexing agent aqueous solution and precipitant aqueous solution were introduced to adjust the complexing agent concentration to 2.2 g / L and the second pH to 10.30, while controlling the reaction temperature at 60℃. A core filter cake weighing 451.5 kg was added. Under a second stirring speed of 360 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 520 L / h. Simultaneously, the complexing agent aqueous solution, precipitant aqueous solution, and inorganic aluminum alkali solution were introduced into the reactor, with the inorganic aluminum alkali solution pumped at a flow rate of 30 L / h. The reaction pH was maintained at the second pH of 10.30. The stirring speed was gradually reduced by 20 rpm per hour, from the second stirring speed to a third stirring speed of 50 rpm. The reaction was stopped when the overall particle size of the reactants reached the target particle size of 13.50 μm.

[0082] After the reaction, the material was transferred to an aging reactor and allowed to stand for 3 hours. The supernatant was then removed, and 3 ml of a 32% sodium hydroxide solution was added. 3The mixture was stirred for 18 hours to allow aluminum hydroxide in the outer core to dissolve, forming a porous and loose structure. The material was then washed with water at 70℃, centrifuged, dried at 130℃, mixed in batches, sieved, and iron removed to obtain a high-nickel ternary precursor with a compact inner structure and a loose outer structure. The precursor had a compact internal structure size of 5.63 μm, a particle size D50 of 13.65 μm, a particle size distribution of 0.33, and a tap density of 1.96 g / cm³. 3 BET is 13.98m 2 / g.

[0083] The ternary precursor material prepared in Example 3 of this invention was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 3-1 , Figure 3-2 As shown, the ternary precursor material prepared in Example 3 of this invention has a compact structure of 5.63 micrometers in the center and a loose porous structure in the outer core.

[0084] Comparative Example 1

[0085] A nickel, cobalt, and manganese inorganic salt with a molar ratio of Ni was prepared. 0.95 Co 0.03 Mn 0.02 Prepare a ternary mixed metal salt solution with a total metal (nickel, cobalt, manganese) concentration of 1.60 mol / L (OH)2; prepare a sodium hydroxide aqueous solution with a concentration of 5 mol / L; prepare an ammonia aqueous solution with a concentration of 8.0 g / L.

[0086] In a volume of 8m 3 The first reaction vessel has a volume of 2m³. 3 The concentrator is filled with pure water and circulated, with nitrogen gas introduced for protection. A complexing agent aqueous solution and a precipitant aqueous solution are introduced to adjust the complexing agent concentration to 2.2 g / L and the initial pH to 11.20, while controlling the reaction temperature at 60℃. Under a first stirring speed of 420 rpm, a ternary mixed metal salt solution is pumped into the reactor at a flow rate of 200 L / h, simultaneously with the complexing agent aqueous solution and the precipitant aqueous solution, maintaining the initial pH at 11.20. When the reactant particle size reaches the target core particle size of 5.5 μm, the introduction of the ternary mixed metal salt solution, complexing agent aqueous solution, and precipitant aqueous solution is stopped. The resulting core slurry is pumped into a centrifuge for washing with water for 300 s at a temperature of 70℃. The core filter cake is then dried until its moisture content is 18% for later use.

[0087] In a volume of 8m 3 The second reaction vessel has a volume of 2m³. 3The concentrator was filled with pure water and circulated, with nitrogen gas introduced as a protective gas. A complexing agent aqueous solution and a precipitant aqueous solution were introduced to adjust the complexing agent concentration to 2.2 g / L and the second pH to 10.30, while controlling the reaction temperature at 60℃. A core filter cake weighing 451.5 kg was added. Under a second stirring speed of 360 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 520 L / h, simultaneously with the complexing agent aqueous solution and the precipitant aqueous solution, maintaining the second pH at 10.30. The stirring speed was gradually reduced by 20 rpm per hour, from the second stirring speed to a third stirring speed of 50 rpm. The reaction was stopped when the overall particle size of the reactants reached the target particle size of 13.50 μm.

[0088] After the reaction, the material was transferred to an aging reactor and allowed to stand for 3 hours. The supernatant was then removed, and 3 ml of a 32% sodium hydroxide solution was added. 3 After stirring for 18 hours, the material was washed and centrifuged at 70℃, dried at 130℃, mixed, sieved, and iron removed to obtain a high-nickel ternary precursor with a tight inner structure and loose outer structure.

[0089] The ternary precursor material prepared in Comparative Example 1 of this invention was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 4-1 , Figure 4-2 As shown, the ternary precursor materials prepared in Comparative Example 1 of this invention all exhibit a compact structure.

[0090] The ternary precursor D50 prepared in Comparative Example 1 of this invention has a diameter of 13.58 μm.

[0091] The ternary precursor prepared in Comparative Example 1 of this invention has a particle size distribution of 0.34 μm.

[0092] The tap density of the ternary precursor prepared in Comparative Example 1 of this invention is 2.06 g / cm³. 3 .

[0093] The ternary precursor prepared in Comparative Example 1 of this invention has a BET of 5.85m. 2 / g.

[0094] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

[0095] Comparative Example 2

[0096] A nickel, cobalt, and manganese inorganic salt with a molar ratio of Ni was prepared. 0.95 Co 0.03 Mn 0.02Prepare a ternary mixed metal salt solution with a total metal (nickel, cobalt, manganese) concentration of 1.60 mol / L (OH)2; prepare a sodium hydroxide aqueous solution with a concentration of 5 mol / L; prepare an ammonia aqueous solution with a concentration of 8.0 g / L.

[0097] In a volume of 8m 3 The first reaction vessel has a volume of 2m³. 3 The concentrator was filled with pure water and circulated, with nitrogen gas introduced for protection. Complexing agent and precipitant solutions were introduced to adjust the complexing agent concentration to 2.2 g / L and the initial pH to 11.20, while controlling the reaction temperature at 60°C. Under a first stirring speed of 420 rpm, a ternary mixed metal salt solution was pumped into the reactor at a flow rate of 200 L / h, simultaneously introducing the complexing agent and precipitant solutions, maintaining the initial pH at 11.20. Once the particle size reached 5.5 μm, the stirring speed was adjusted to a second stirring speed of 360 rpm, and the ternary mixed metal salt solution was pumped into the reactor at a flow rate of 520 L / h, adjusting the initial pH to a second pH of 10.30. The stirring speed was gradually reduced by 20 rpm per hour, from the second stirring speed to a third stirring speed of 50 rpm. The reaction was stopped when the overall particle size reached the target of 13.50 μm.

[0098] After the reaction, the material was transferred to an aging reactor and allowed to stand for 3 hours. The supernatant was then removed, and 3 ml of a 32% sodium hydroxide solution was added. 3 After stirring for 18 hours, the material was washed and centrifuged at 70℃, dried at 130℃, mixed, sieved, and iron removed to obtain a high-nickel ternary precursor with a tight inner structure and loose outer structure.

[0099] The ternary precursor material prepared in Comparative Example 2 of this invention was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 5-1 , Figure 5-2 As shown, the ternary precursor material prepared in Comparative Example 2 of this invention exhibits a compact structure overall, and the particles show obvious spherical cracking.

[0100] The ternary precursor D50 prepared in Comparative Example 2 of this invention has a diameter of 13.63 μm.

[0101] The ternary precursor prepared in Comparative Example 2 of this invention has a particle size distribution of 0.36 μm.

[0102] The tap density of the ternary precursor prepared in Comparative Example 2 of this invention is 2.11 g / cm³. 3 .

[0103] The ternary precursor prepared in Comparative Example 2 of this invention has a BET of 4.61 m. 2 / g.

[0104] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A preparation method of an inner-tight outer-loose type high-nickel ternary precursor, characterized by, It comprises the following steps: (1) A ternary mixed metal salt solution is prepared by using nickel, cobalt and manganese inorganic salts; an inorganic aluminum base solution is prepared; an aqueous precipitant solution is prepared; and an aqueous complexing agent solution is prepared; (2) The first reactor and the first concentrator are filled with pure water and circulated, and protective gas is introduced, and the aqueous complexing agent solution and the aqueous precipitant solution are introduced to adjust the complexing agent concentration and the first pH, and the reaction temperature is controlled; Under the first stirring speed, the ternary mixed metal salt solution, the aqueous complexing agent solution and the aqueous precipitant solution are simultaneously introduced into the reactor, and the reaction pH is controlled to keep the first pH; When the particle size of the reactant reaches the core target particle size, the feeding of the solution is stopped, and the core slurry after the reaction is pumped into a centrifuge for water washing and drying to obtain a core filter cake; (3) The second reactor and the second concentrator are filled with pure water and circulated, and protective gas is introduced, and the aqueous complexing agent solution and the aqueous precipitant solution are introduced to adjust the complexing agent concentration and the second pH, and the reaction temperature is controlled, and a certain amount of core filter cake is introduced; Under the second stirring speed, the ternary mixed metal salt solution, the aqueous complexing agent solution, the aqueous precipitant solution and the inorganic aluminum base solution are simultaneously introduced into the reactor, and the reaction pH is controlled to keep the second pH, and the reaction stirring is decreased from the second stirring speed to the third stirring speed in a stepwise manner; When the particle size of the reactant reaches the overall target particle size, the reaction is stopped; (4) The material after the reaction is transferred to an aging kettle, and the supernatant is removed after standing, and a strong alkali solution is added and stirred; and after post-treatment, a high-nickel ternary precursor with a tight inner and loose outer structure is obtained; In the step (2), the centrifuge water washing time is 200-800 s; and the moisture content of the core filter cake is 10-25%; In the step (3), the reaction temperature of the second reactor is 45-70℃; the reaction complexing agent concentration is 0.5-10.0 g / L; the reaction second pH is 10.00-11.20; the second stirring speed is 150-300 rpm, and the third stirring speed is 30-100 rpm; the ternary mixed metal salt solution pump-in flow rate is 30-600 L / h; the inorganic aluminum base solution pump-in flow rate is 2-100 L / h; and the overall target particle size is 8-18 μm; The weight of the input into the kernel filter cake is (aV / D 3 *d 3 ) kg; wherein: a is a constant, and the value range is 200-800; V is the second reactor volume in m 3 ; D is the overall target particle size, and the unit is μm; d is the core target particle size, and the unit is μm; s is the moisture content of the filter cake, and the unit is %.

2. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, The inorganic salt of nickel, cobalt and manganese in step (1) is one or more of corresponding sulfate, nitrate and chloride, the total concentration of metals in the ternary mixed metal salt solution is 1.0-2.3 mol / L, and the ratio of nickel, cobalt and manganese in the ternary mixed metal salt solution conforms to the formula Ni x Co y Mn (1-x-y) (OH)2, wherein 0 < x < 0.98 and 0 < y < 0.

40.

3. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, In the step (1), the inorganic aluminum in the inorganic aluminum base solution is one or more of sodium metaaluminate and aluminum sulfate; the aluminum concentration in the inorganic aluminum base solution is 0.10-1.0 mol / L; the base is one or more of sodium hydroxide and potassium hydroxide, and the pH value is 13.00-13.

50.

4. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, In the step (1), the precipitant is one or more of sodium hydroxide and potassium hydroxide, and the aqueous precipitant solution concentration is 5.0-12.0 mol / L.

5. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, In the step (1), the complexing agent is one or more of ammonia, ammonium sulfate, sodium ascorbate, salicylic acid and oxalic acid, and the aqueous complexing agent solution concentration is 1.0-11.0 g / L.

6. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, The reaction temperature of the first reactor in the step (2) is 45-70 ℃; the reaction complexing agent concentration is 0.5-10.0 g / L; the first reaction pH is 10.30-11.00; the first stirring speed is 200-540 rpm; the ternary mixed metal salt solution pump-in flow is 30-600 L / h; and the core target particle size is 3.0-7.0 μm.

7. The preparation method of the inner-tight-outer-loose type high-nickel ternary precursor according to claim 1, characterized in that, The strong base added in the step (4) is at least one of sodium hydroxide and potassium hydroxide, and the volume of the strong base is 0.5-5mL 3 , and the stirring time is 10-24h.

8. An inner-tight outer-loose type high-nickel ternary precursor prepared by the preparation method of any one of claims 1-7.

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