A ternary precursor with continuously controllable particle size distribution width, a preparation method thereof, a positive electrode material, a lithium ion battery and an electric device
By designing a ternary precursor with continuously controllable particle size distribution, adopting a structure of secondary particles A and B, and controlling the particle size by adjusting the rotation speed and salt solution flow rate, the problem of non-uniformity of the ternary precursor during high-temperature sintering was solved, thereby improving the performance of battery materials and the service life of batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JINCHI ENERGY MATERIALS CO LTD
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-16
AI Technical Summary
The particle size distribution of existing ternary precursors is difficult to adjust continuously, which leads to problems such as excessive crystallization of small particles and incomplete crystallization of large particles during the high-temperature sintering process of battery materials, affecting the uniformity and electrochemical performance of the materials.
The design employs secondary particles A and secondary particles B, with the particle size of secondary particle A being smaller than that of secondary particle B. The shell of secondary particle A is blocky or spindle-shaped, while the shell of secondary particle B is sheet-like. The particle size distribution is controlled by adjusting the rotation speed and the flow rate of the transition metal salt solution, and the size of the primary particles is adjusted by air oxidation, thus achieving continuous and controllable particle size distribution.
It improves the sintering uniformity of the cathode material, enhances the specific capacity, cycle stability, and ion/electron conductivity of the battery material, and improves the cycle life and safety of lithium-ion batteries.
Smart Images
Figure CN121929758B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of lithium-ion batteries, and in particular to a ternary precursor with continuously controllable particle size distribution and its preparation method, cathode material, lithium-ion battery and electrical device. Background Technology
[0002] The particle size distribution of ternary precursors directly affects the effective filling of voids and compaction density of battery electrodes, further influencing the volumetric energy density of the battery. It also affects the processing performance and electrolyte wettability of the electrodes, making it crucial to the overall performance of the battery. To match cathode active materials with suitable particle size distributions, cathode material gradations with different particle size distributions are generally used. Currently, the mainstream production processes for precursors include continuous processes, continuous multi-stage series reactor processes, and batch processes. In continuous and batch processes, once the process parameters and synthesis equipment are determined, the particle size distribution tends to be fixed and difficult to adjust through the synthesis process. While continuous multi-stage series reactor processes can adjust the particle size distribution by increasing the number of reactor stages or adding flow-cutting equipment such as hydrocyclones, the resource investment is large and the adjustment methods are cumbersome. On the other hand, regardless of the production process, the primary particle size of small particles in the same batch of precursors is smaller than that of large particles. However, in the high-temperature solid-state reaction of ternary precursor sintering, the precursor needs to react with the lithium source and grow into a regular crystal. For particles with smaller primary particle size, heat is more easily transferred from the surface to the center, so the reaction and crystal growth are completed faster. On the other hand, particles with larger particle size require a longer heating time, which may lead to insufficient reaction. As a result, in the same batch of materials, small particles may have been over-sintered, while large particles may not have crystallized completely or even contain impurities. This structural inhomogeneity will directly lead to fluctuations in the intrinsic electrochemical properties of the material.
[0003] Therefore, there is an urgent need to provide a ternary precursor with continuously controllable primary particle size and secondary particle size distribution width to solve the above-mentioned problem. Summary of the Invention
[0004] The purpose of this application is to provide a ternary precursor with continuously controllable particle size distribution width, its preparation method, cathode material, lithium-ion battery, and electrical device to solve the above-mentioned problems.
[0005] To achieve the above objectives, the first aspect of this application provides a ternary precursor with continuously controllable particle size distribution width, comprising secondary particles A and secondary particles B, wherein secondary particles A comprises primary particles a and secondary particles B comprises primary particles b.
[0006] The particle size of the secondary particle A is smaller than that of the secondary particle B; the particle size of the primary particle a is larger than that of the primary particle b.
[0007] The secondary particle A and the secondary particle B each independently include a core and a shell layer disposed on the surface of the core. The primary particle a of the shell layer of the secondary particle A is blocky and / or spindle-shaped, and the primary particle b of the shell layer of the secondary particle B is sheet-like.
[0008] Optionally, the number of secondary particles B is less than or equal to 50% of the total number of the ternary precursors;
[0009] And / or, the particle size of the secondary particle B is 0.8 × D. 三元前驱体v50 -D 三元前驱体v Max ;
[0010] And / or, the particle size of the secondary particle A is D. 三元前驱体v min -1.2×D 三元前驱体v50 .
[0011] Optionally, the particle size of the secondary particle A is 1.2-7 μm;
[0012] And / or, the particle size of the secondary particle B is 2.4-10 μm;
[0013] And / or, the particle size of the primary particle a in the shell is 80-200 nm;
[0014] And / or, the particle size of the primary particles b in the shell is 20-60 nm;
[0015] And / or, the shell thickness of the secondary particle A is 0.3-0.7 μm;
[0016] And / or, the shell thickness of the secondary particle B is 0.8-2 μm.
[0017] Optionally, the general chemical formula of the ternary precursor is Ni. x Co y Mn z (OH)2, where 0.3≤x≤0.8, 0≤y≤0.3, 0≤z≤0.7, and x+y+z=1;
[0018] And / or, the span of the ternary precursor is 0.7-1.35;
[0019] And / or, the D50 of the ternary precursor is 3μm-6.5μm;
[0020] And / or, the TD of the ternary precursor is 1.2 g / cm³. 3 -1.9g / cm 3 ;
[0021] And / or, the SSA of the ternary precursor is 7m. 2 / g-25m 2 / g.
[0022] A second aspect of this application provides a method for preparing a ternary precursor with continuously controllable particle size distribution width, comprising:
[0023] A transition metal salt solution, an alkaline solution, and ammonia water are introduced into the base liquid A to carry out the first reaction and obtain the seed slurry.
[0024] The seed slurry, transition metal salt solution, ammonia and alkaline solution are introduced into the bottom liquid B, and a second reaction is carried out in an oxygen-containing gas to obtain a lithium-rich manganese-based hydroxide precursor.
[0025] The second reaction satisfies:
[0026] ;
[0027] Among them, L 晶种 L represents the theoretical flow rate of the seed slurry, in L / min. 盐 The flow rate of the transition metal salt solution is expressed in L / min; W 盐 M represents the molar concentration of a transition metal salt solution, in mol / L. 盐 W represents the molar molecular weight of the lithium-rich manganese-based hydroxide precursor, in g / mol. 晶种 R represents the solid content of the seed slurry, in g / L. 成品 D50 of the lithium-rich manganese-based hydroxide precursor, in μm; R 晶种 D50 of the seed crystals in the seed slurry, in μm.
[0028] Optionally, the temperature of the second reaction is 45-75°C;
[0029] And / or, in the second reaction process, the rotation speed is 2.5m / s-8m / s, the hourly feed volume of the transition metal salt solution is 4%-18% of the reactor volume, and the molar ratio of oxygen molecules in the oxygen-containing gas to Mn in the transition metal salt solution is 1:1.5-3.
[0030] And / or, the second reaction is carried out in a reactor, the height of the bottom liquid B is up to the height of the overflow valve in the reactor, and after the particle size of the material in the second reaction reaches the preset particle size, the slurry discharged from the overflow port of the reactor is collected, and the slurry is aged, washed, dried and screened to obtain the lithium-rich manganese-based hydroxide precursor.
[0031] And / or, the molar concentration of the transition metal salt solution is 1.8-2.2 mol / L;
[0032] And / or, the flow rate of the seed slurry is 70%. L晶种 -130% L 晶种 mL / min;
[0033] And / or, the hourly feed volume of the transition metal salt solution is 4%-18% of the reactor volume;
[0034] And / or, the solid content of the seed slurry is 200-500 g / L;
[0035] And / or, the D50 of the seed crystals in the seed slurry is 2.5-6 μm.
[0036] Optionally, the ammonia concentration in the substrate solution A is 3-12 g / L, and the pH is 11.5-12.20;
[0037] And / or, the temperature of the first reaction is 40-70℃, the pH value is reduced to 10.0-11.6 after 20-180 min, and the oxygen content is ≤3%;
[0038] And / or, the primary particles in the seed crystal are coarse strips with a thickness of 60-200 nm;
[0039] And / or, the ammonia concentration of the substrate B is 3-10 g / L, and the pH is 10.0-10.70.
[0040] A third aspect of this application provides a cathode material, including the aforementioned ternary precursor with continuously controllable particle size distribution width.
[0041] A fourth aspect of this application provides a lithium-ion battery, including the aforementioned positive electrode material.
[0042] The fifth aspect of this application provides an electrical device including the aforementioned lithium-ion battery.
[0043] Compared with the prior art, the beneficial effects of this application include:
[0044] The ternary precursor provided in this application has a continuously controllable particle size distribution. The secondary particles A (small particle size) have large primary particle sizes, while the secondary particles B (large particles) have slender primary particle sizes. During calcination, this can alleviate the phenomenon of excessive crystallization of small particles and incomplete crystallization of large particles, thereby improving the uniformity of cathode material sintering. The particle size distribution of the ternary precursor is continuously controllable, and the particle size distribution can be easily and conveniently adjusted according to the needs of downstream battery manufacturers without the need for additional equipment. The adjustment method is simple and controllable, making it suitable for large-scale production.
[0045] The method for preparing a ternary precursor with continuously controllable particle size distribution width provided in this application allows for adjustment of the precursor span by adjusting the rotation speed and the flow rate of the mixed salt solution.
[0046] The cathode material provided in this application effectively balances the crystallization differences of ternary precursor particles of different sizes during high-temperature calcination, making the overall structure of the cathode material more uniform and effectively improving the specific capacity, cycle stability and ion / electron conduction capability of the battery material.
[0047] The lithium-ion batteries and electrical devices provided in this application have improved cycle life and safety, and are more durable and reliable. Attached Figure Description
[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.
[0049] Figure 1 SEM image of the seed slurry provided in Example 1;
[0050] Figure 2 SEM image of the ternary precursor provided in Example 1;
[0051] Figure 3 A cross-sectional SEM image of secondary particles A of the ternary precursor provided in Example 1;
[0052] Figure 4 A cross-sectional SEM image of secondary particles B of the ternary precursor provided in Example 1;
[0053] Figure 5 SEM image of the ternary precursor provided for Comparative Example 4;
[0054] Figure 6 SEM image of the ternary precursor provided for Comparative Example 5. Detailed Implementation
[0055] First, the solution provided in this application will be explained in more detail as follows:
[0056] The first aspect of this application provides a ternary precursor with continuously controllable particle size distribution width, including secondary particles A and secondary particles B, wherein secondary particles A include primary particles a and secondary particles B include primary particles b.
[0057] The particle size of the secondary particle A is smaller than that of the secondary particle B; the particle size of the primary particle a is larger than that of the primary particle b.
[0058] The secondary particle A and the secondary particle B each independently include a core and a shell layer disposed on the surface of the core. The primary particle a of the shell layer of the secondary particle A is blocky and / or spindle-shaped, and the primary particle b of the shell layer of the secondary particle B is sheet-like.
[0059] In some embodiments, the number of secondary particles B is less than or equal to 50% of the total number of the ternary precursors;
[0060] Optionally, the number of secondary particles B can be any value that accounts for 50%, 45%, 40%, 35%, 30% or less than or equal to 50% of the total number of ternary precursors.
[0061] It should be noted that since the overflow valve in reactor B (the reaction vessel for the second reaction) is always open, each precursor particle has an equal chance of overflowing. Therefore, the precursor particles with larger diameters are formed by the growth of precursors that have stayed in reactor B for a longer period of time. The primary particle thickness can be refined through continuous air oxidation. Conversely, the precursor particles with smaller diameters are formed by the shorter period of time they have stayed in reactor B. They are less affected by air oxidation, and the primary particle size will not be refined.
[0062] And / or, the particle size of the secondary particle B is 0.8 × D. 三元前驱体v50 -D 三元前驱体vMax ;
[0063] This can be understood as the particle size range of secondary particle B being 0.8 × the D of the ternary precursor. v50 -D of the ternary precursor vMax ;
[0064] And / or, the particle size of the secondary particle A is D. 三元前驱体vmin -1.2×D 三元前驱体v50 .
[0065] This can be understood as the particle size range of secondary particle A being equal to that of the ternary precursor D. vmin -D of the ternary precursor v50 .
[0066] In some embodiments, the particle size of the secondary particle A is 1.2-7 μm;
[0067] Optionally, the particle size of secondary particle A can be any value between 1.2μm, 2.4μm, 3μm, 4μm, 5μm, 6μm, 7μm or 1.2-7μm;
[0068] And / or, the particle size of the secondary particle B is 2.4-10 μm;
[0069] Optionally, the particle size of secondary particle B can be 2.4μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm or any value between 2.4 and 10μm;
[0070] And / or, the particle size of the primary particle a in the shell is 80-200 nm;
[0071] Optionally, the particle size of the primary particle a in the shell can be any value between 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, or 80-200 nm.
[0072] And / or, the particle size of the primary particles b in the shell is 20-60 nm;
[0073] Optionally, the particle size of the primary particle b in the shell can be any value between 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or 20-60 nm.
[0074] And / or, the shell thickness of the secondary particle A is 0.3-0.7 μm;
[0075] Optionally, the thickness of the shell of secondary particle A can be any value between 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, or 0.3-0.7 μm;
[0076] And / or, the shell thickness of the secondary particle B is 0.8-2 μm.
[0077] Optionally, the thickness of the shell of secondary particle B can be any value between 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm or 0.8-2 μm.
[0078] In some embodiments, the general chemical formula of the ternary precursor is Ni. x Co y Mn z (OH)2, where 0.3≤x≤0.8, 0≤y≤0.3, 0≤z≤0.7, and x+y+z=1;
[0079] Optionally, in the general chemical formula of the ternary precursor, x can be any value between 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.3-0.8, y can be any value between 0, 0.1, 0.2, 0.3 or 0-0.3, and Z can be any value between 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0-0.7;
[0080] And / or, the span of the ternary precursor is 0.7-1.35;
[0081] Optionally, the span of the ternary precursor can be any value between 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.35, or 0.7-1.35;
[0082] And / or, the D50 of the ternary precursor is 3μm-6.5μm;
[0083] Optionally, the D50 of the ternary precursor can be any value between 3μm, 4μm, 5μm, 6μm, 6.5μm, or 3-6.5μm;
[0084] And / or, the TD of the ternary precursor is 1.2 g / cm³. 3 -1.9g / cm 3 ;
[0085] Optionally, the TD of the ternary precursor can be 1.2 g / cm³. 3 1.4 g / cm 3 1.6 g / cm 3 1.8 g / cm 3 1.9g / cm 3 Or 1.2-1.9 g / cm³ 3 Any value between;
[0086] And / or, the SSA of the ternary precursor is 7m. 2 / g-25m 2 / g.
[0087] Optionally, the SSA of the ternary precursor can be 7 m. 2 / g、10 m 2 / g、15 m 2 / g、20 m 2 / g、25m 2 / g or 7-25 m 2 Any value between / g.
[0088] A second aspect of this application provides a method for preparing a ternary precursor with continuously controllable particle size distribution width, comprising:
[0089] A transition metal salt solution, an alkaline solution, and ammonia water are introduced into the base liquid A to carry out the first reaction and obtain the seed slurry.
[0090] The seed slurry, transition metal salt solution, ammonia and alkaline solution are introduced into the bottom liquid B, and a second reaction is carried out in an oxygen-containing gas to obtain a lithium-rich manganese-based hydroxide precursor.
[0091] The second reaction satisfies:
[0092] ;
[0093] Among them, L 晶种 L represents the theoretical flow rate of the seed slurry, in L / min. 盐The flow rate of the transition metal salt solution is expressed in L / min; W 盐 M represents the molar concentration of a transition metal salt solution, in mol / L. 盐 W represents the molar molecular weight of the lithium-rich manganese-based hydroxide precursor, in g / mol. 晶种 R represents the solid content of the seed slurry, in g / L. 成品 D50 of the lithium-rich manganese-based hydroxide precursor, in μm; R 晶种 D50 of the seed crystals in the seed slurry, in μm.
[0094] It is important to note that the final particle size of the ternary precursor is controlled by the flow rate of the seed slurry used in the second reaction. To achieve a larger final particle size, the seed slurry flow rate should be reduced from the theoretical flow rate, and vice versa. Reactor B (the reaction vessel for the second reaction) is a continuous growth reactor. No secondary nucleation occurs during precursor growth. The slurry overflows while the raw material is introduced, maintaining a constant slurry volume within the reactor. When other conditions are constant, particle size stability is maintained solely by adjusting the seed slurry flow rate. Therefore, it can be assumed that all the sulfate raw material introduced into reactor B is used for seed growth. The theoretical slurry flow rate can then be calculated using the relationship between the volume and radius of spherical particles. In actual production, the equilibrium seed slurry flow rate at which the particle size in reactor B is stable can be quickly determined based on the calculated theoretical flow rate, thereby improving production efficiency and process stability.
[0095] Specifically, when the rotation speed is increased, the distribution of transition metal ions and hydroxide ions in the liquid phase is uniform, the supersaturation in the reactor is uniform, the local supersaturation phenomenon is slight, and the excessive growth of some particles is not likely to occur, thus the span is low; when the rotation speed is decreased, local supersaturation occurs, and the particles at the solution supply point grow preferentially, resulting in a wider span.
[0096] In some embodiments, the rotational speed in reactor B is 2.5 m / s to 7.6 m / s.
[0097] When the salt flow rate is increased, the residence time of the precursor particles in the reactor becomes shorter, and the precursor particles cannot grow sufficiently, resulting in a wider span. When the salt flow rate is decreased, the residence time of the precursor particles in the reactor becomes longer, and even small particles can grow sufficiently, thus narrowing the span.
[0098] In some embodiments, the volume of mixed metal salt entering reactor B per hour is 4%-15% of the reactor volume.
[0099] The secondary particle size of 0.8 mm can be achieved by controlling the flow rate of oxygen-containing gas in reactor B. In the Dv50-DvMax range, the primary particle size of precursors is refined because the overflow valve in reactor B is always open, and each precursor particle has an equal chance of overflowing. Therefore, larger precursor particles are formed by the growth of precursors that have stayed in reactor B for a longer period of time, and the primary particle thickness can be refined through continuous air oxidation. Conversely, smaller precursor particles are formed by the shorter residence time in reactor B, and are less affected by air oxidation, so the primary particle size will not be refined.
[0100] In some embodiments, the molar ratio of oxygen molecules in the oxygen-containing gas to Mn element in the mixed metal salt is m. 氧 / m 锰 =1 / 3-1 / 1.5.
[0101] In some embodiments, the temperature of the second reaction is 45-75°C;
[0102] Optionally, the temperature of the second reaction can be any value between 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 45-75℃.
[0103] And / or, in the second reaction process, the rotation speed is 2.5m / s-8m / s, the hourly feed volume of the transition metal salt solution is 4%-18% of the reactor volume, and the molar ratio of oxygen molecules in the oxygen-containing gas to Mn in the transition metal salt solution is 1:1.5-3.
[0104] Optionally, during the second reaction, the rotation speed can be any value between 2.5 m / s, 3 m / s, 4 m / s, 5 m / s, 6 m / s, 7 m / s, 8 m / s, or 2.5-8 m / s. The hourly feed volume of the transition metal salt solution can be any value between 4%, 8%, 12%, 14%, 18%, or 4-18% of the reactor volume. The molar ratio of oxygen molecules in the oxygen-containing gas to Mn in the transition metal salt solution can be any value between 1:1.5, 1:2, 1:2.5, 1:3, or 1:1.5-3.
[0105] It is important to note that the span of the ternary precursor can be adjusted by modifying the rotation speed of the second reaction and the flow rate of the transition metal salt solution. Specifically, when the rotation speed is increased, the distribution of the transition metal salt solution and hydroxide ions in the liquid phase is more uniform, the supersaturation is more uniform throughout the reactor, and local supersaturation is less likely to occur, thus reducing the likelihood of excessive growth of some particles and resulting in a lower span. When the rotation speed is decreased, local supersaturation occurs, and particles at the solution supply point grow preferentially, leading to a wider span. When the flow rate of the transition metal salt solution is increased, the residence time of precursor particles in the reactor is shorter, and individual precursor particles cannot grow sufficiently, resulting in a wider span. When the flow rate of the transition metal salt solution is decreased, the residence time of precursor particles in the reactor is reduced, and even small particles can grow sufficiently, thus narrowing the span. Therefore, to increase the span value, it can be achieved by decreasing the rotation speed and increasing the flow rate of the transition metal salt solution.
[0106] It should also be noted that by controlling the flow rate of oxygen-containing gas, the particle size of secondary particles B can be achieved to be 0.8 × D. 三元前驱体v50 -D 三元前驱体v Max The refinement of primary particles b in the precursor within the range is achieved because the overflow valve in the reactor of the second reaction is always open, and each precursor particle has an equal probability of overflowing. Therefore, precursor particles with larger diameters stay in the reactor for a longer time, and the thickness of the primary particles can be refined through continuous air oxidation. Conversely, precursor particles with smaller diameters stay in the reactor for a shorter time and are less affected by air oxidation, so the size of the primary particles is not refined. This can be understood as follows: by continuously introducing oxygen-containing gas into the reactor of the second reaction and utilizing the grading mechanism formed by the constantly open overflow valve, the internal structure of particles of different diameters is differentially controlled. Specifically, larger particles obtained by a longer residence time are more affected by oxidation, and the primary particles are refined; smaller particles obtained by a shorter residence time are less affected by continuous oxidation, and the primary particles remain coarse. This design optimizes the primary particle structure of particles of different sizes separately, thereby matching the subsequent sintering requirements and improving the overall uniformity of the cathode material.
[0107] Preferably, the rotational speed of the second reaction is 2.5 m / s to 7.6 m / s;
[0108] And / or, the second reaction is carried out in a reactor, the height of the bottom liquid B is up to the height of the overflow valve in the reactor, and after the particle size of the material in the second reaction reaches the preset particle size, the slurry discharged from the overflow port of the reactor is collected, and the slurry is aged, washed, dried and screened to obtain the lithium-rich manganese-based hydroxide precursor.
[0109] And / or, the molar concentration of the transition metal salt solution is 1.8-2.2 mol / L;
[0110] Optionally, the molar concentration of the transition metal salt solution can be any value between 1.8 mol / L, 1.9 mol / L, 2 mol / L, 2.1 mol / L, 2.2 mol / L, or 1.8-2.2 mol / L;
[0111] And / or, the flow rate of the seed slurry is 70%. L 晶种 -130% L 晶种 mL / min;
[0112] Optionally, the flow rate of the seed slurry can be 70%. L 晶种 mL / min, 80% L 晶种 mL / min, 90% L 晶种 mL / min, 100% L 晶种 mL / min, 110% L 晶种 mL / min, 120% L 晶种 mL / min, 130% L 晶种 mL / min or 70% L 晶种 -130% L 晶种 Any value between mL / min;
[0113] And / or, the hourly feed volume of the transition metal salt solution is 4%-18% of the reactor volume;
[0114] Optionally, the hourly feed volume of the transition metal salt solution can be any value between 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 4-18% of the reactor volume.
[0115] And / or, the solid content of the seed slurry is 200-500 g / L;
[0116] Optionally, the solid content of the seed slurry can be any value between 200 g / L, 300 g / L, 400 g / L, 500 g / L or 200-500 g / L;
[0117] And / or, the D50 of the seed crystals in the seed slurry is 2-3.6 μm.
[0118] Optionally, the D50 of the seed crystals in the seed slurry can be any value between 2μm, 2.5μm, 3μm, 3.6μm, or 2-3.6μm.
[0119] In some embodiments, the ammonia concentration in the substrate A is 3-12 g / L, and the pH is 11.5-12.20;
[0120] Optionally, the ammonia concentration in the base solution A can be any value between 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, or 3-12 g / L, and the pH can be any value between 11.5, 11.6, 11.7, 11.8, 11.9, 12, 12.1, 12.2, or 11.5-12.2.
[0121] And / or, the temperature of the first reaction is 40-70℃, the pH value is reduced to 10.0-11.6 after 20-180 min, and the oxygen content is ≤3%;
[0122] Optionally, the temperature of the first reaction can be any value between 40℃, 50℃, 60℃, 70℃ or 40-70℃, the reaction time can be 20 min, 30 min, 60 min, 90 min, 120 min, 150 min, 180 min or 20-180 min, the pH can be any value between 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6 or 10-11.6, and the oxygen content can be any value between 3%, 2%, 1% or ≤3%.
[0123] And / or, the primary particles in the seed crystal are coarse strips with a thickness of 60-200 nm;
[0124] Optionally, the thickness of the primary particles in the seed crystal can be any value between 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm or 60-200 nm.
[0125] And / or, the ammonia concentration of the substrate B is 3-10 g / L, and the pH is 10.0-10.70.
[0126] Optionally, the ammonia concentration of the substrate solution B can be any value between 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L or 3-10 g / L, and the pH can be any value between 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7 or 10-10.7.
[0127] A third aspect of this application provides a cathode material, including the aforementioned ternary precursor with continuously controllable particle size distribution width.
[0128] A fourth aspect of this application provides a lithium-ion battery, including the aforementioned positive electrode material.
[0129] The fifth aspect of this application provides an electrical device including the aforementioned lithium-ion battery.
[0130] It should be noted that electrical equipment may include, but is not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc.; among them, mobile devices may include, but are not limited to, at least one of mobile phones, laptops, etc.; electric vehicles may include, but are not limited to, at least one of pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.
[0131] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.
[0132] Example 1
[0133] This embodiment provides a ternary precursor with continuously controllable particle size distribution and its preparation method. The specific preparation steps are as follows:
[0134] S1. Preparation of seed slurry: Prepare a mixed metal salt solution with a molar concentration of 2 mol / L and a nickel-cobalt-manganese ratio of 5:2:3; prepare a sodium hydroxide solution with a molar concentration of 10 mol / L and an ammonia solution with a molar concentration of 10 mol / L; prepare a reaction base solution in reactor A, adjust the ammonia concentration of the base solution to 9 g / L, the pH to 12.0, and the reaction temperature to 55℃. Then, simultaneously introduce the mixed salt solution containing nickel-cobalt-manganese ions, the sodium hydroxide solution, and the ammonia solution into the reactor. After reacting for 40 min, lower the pH to 11.0 and continuously introduce high-purity nitrogen to control the oxygen content in the atmosphere of the reactor to <3% until the seed crystal D50 reaches 3.4 μm, then stop introducing the mixed salt solution, sodium hydroxide solution, and ammonia solution to obtain a seed slurry with a solid content of 374 g / L.
[0135] S2: Add pure water to the overflow valve level in reactor B (100L volume), add ammonia to adjust the ammonia concentration to 7g / L, and add sodium hydroxide solution to adjust the pH to 10.40. Control the reaction temperature at 50℃. Open the overflow valve and simultaneously introduce a mixed salt solution, sodium hydroxide solution, ammonia solution, seed slurry from reactor A, and oxygen-containing gas into reactor B. Set the rotation speed to 4m / s, and the flow rate of the mixed salt solution entering reactor B is 0.15L / min. Air was continuously introduced at a flow rate of 4 L / min. The initial flow rate of the seed slurry introduced into reactor B was set to 79 mL / min. After the precursor particle size in reactor B reached 4.2 μm, the flow rate of the seed slurry was adjusted to maintain the precursor particle size in the reactor at 4.2 μm. Subsequently, the slurry discharged from the overflow port of the reactor was collected. After aging, washing, drying and sieving, a ternary precursor with a span of 0.82 was obtained, with large primary particles being long and thin and small primary particles being short and thick.
[0136] SEM image of the seed slurry obtained in step S1 is as follows: Figure 1 As shown; the SEM image of the ternary precursor obtained in step S2 is shown. Figure 2 As shown.
[0137] The ternary precursor includes secondary particles A and B. The cross-sectional SEM image of secondary particle A is shown below. Figure 3 SEM profile of secondary particle B as shown Figure 4 .
[0138] The number of secondary particles B is less than or equal to 50% of the total number of ternary precursors.
[0139] Example 2
[0140] The difference from Example 1 is that in step S2, the rotational speed is set to 2.8 m / s.
[0141] Example 3
[0142] The difference from Example 1 is that in step S2, the air flow rate is set to 6 L / min.
[0143] Comparative Example 1
[0144] The difference from Example 1 is that in step S2, the rotational speed is set to 1.5 m / s.
[0145] Comparative Example 2
[0146] The difference from Example 1 is that in step S2, the feed volume of the transition metal salt solution per hour is 3% of the reactor volume, i.e., 50 mL / min.
[0147] Comparative Example 3
[0148] The difference from Example 1 is that in step S2, the hourly feed volume of the transition metal salt solution is 20% of the reactor volume, i.e., 333 mL / min.
[0149] Comparative Example 4
[0150] The difference from Example 1 is that in step S2, the reaction is carried out in an inert atmosphere.
[0151] SEM images of the ternary precursors prepared in this comparative example are shown below. Figure 5 As shown.
[0152] Comparative Example 5
[0153] The difference from Example 1 is that in step S2, the molar ratio of oxygen molecules in the oxygen-containing gas to Mn in the transition metal salt solution is 1:1.2, that is, the air flow rate is 8L / min.
[0154] SEM images of the ternary precursors prepared in this comparative example are shown below. Figure 6 As shown.
[0155] The relevant product features of the ternary precursors provided in the above embodiments and comparative examples are shown in Table 1.
[0156] Table 1 Product Features
[0157]
[0158] The ternary precursors obtained in the above examples and comparative examples were mixed with lithium carbonate at a molar ratio of 1:1.06 to obtain a mixed lithium sintering precursor. The mixed lithium sintering precursor material was placed in an air atmosphere muffle furnace and heated to 500°C at 3°C / min and held for 5 hours. Then, the temperature was increased to 800°C at 3°C / min and held for 10 hours to obtain the positive electrode material. The positive electrode material was then subjected to electrochemical performance testing using a button cell. The above positive electrode material, conductive carbon black, and binder PVDF (polyvinylidene fluoride) were mixed into a slurry at a ratio of 8.5:1.5:1.5 and coated onto aluminum foil to form a positive electrode sheet. The negative electrode sheet was a lithium metal sheet, and the electrolyte was 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1). The battery case, positive and negative electrode sheets, separator, spring sheet, and gasket were assembled into a button cell in a vacuum glove box. The coin cells prepared in the above examples and comparative examples were subjected to electrochemical performance tests, and the specific test results are shown in Table 2.
[0159] Table 2 Electrochemical Performance
[0160]
[0161] analyze:
[0162] The above tests show that increasing the salt flow rate in S2 or decreasing the rotation speed can increase the precursor span, and vice versa. Adjusting the molar ratio of oxygen molecules to Mn in S2 can effectively control the particle size of the primary particles b in secondary particles B. When the oxygen molecular weight is insufficient, the primary particles b in secondary particles B cannot be effectively refined, resulting in a particle size larger than that of primary particles a. When the oxygen molecular weight is too sufficient, the primary particles b become curved α-Ni(OH)2 morphology.
[0163] As can be seen from the comparison of electrical performance, the embodiment has better overall performance in terms of discharge capacity and capacity retention.
[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
[0165] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
Claims
1. A ternary precursor with continuously controllable particle size distribution width, characterized in that, It includes secondary particles A and secondary particles B, wherein secondary particle A includes primary particle a and secondary particle B includes primary particle b; The particle size of the secondary particle A is smaller than that of the secondary particle B; the particle size of the primary particle a is larger than that of the primary particle b. The secondary particle A and the secondary particle B each independently include a core and a shell layer disposed on the surface of the core. The primary particle a of the shell layer of the secondary particle A is blocky and / or spindle-shaped, and the primary particle b of the shell layer of the secondary particle B is sheet-shaped. The span of the ternary precursor is 0.7-1.35; The TD of the ternary precursor is 1.2 g / cm 3 -1.9 g / cm 3 ; The secondary particle A has a particle size of 1.2-7 μm; The secondary particle B has a particle size of 2.4-10 μm; The primary particles a in the shell layer have a particle size of 80-200 nm; The primary particles b in the shell have a particle size of 20-60 nm; The shell thickness of the secondary particle A is 0.3-0.7 μm; The shell thickness of the secondary particle B is 0.8-2 μm.
2. The ternary precursor with continuously controllable particle size distribution width according to claim 1, characterized in that, The number of secondary particles B is less than or equal to 50% of the total number of the ternary precursors; and / or the particle size of the secondary particles B is 0.8 x D 三元前驱体v50 - D 三元前驱体v Max ; and / or, the particle size of the secondary particles A is D 三元前驱体v min - 1.2 x D 三元前驱体v50 .
3. A ternary precursor with continuously controllable particle size distribution width according to claim 1 or 2, characterized in that, The general chemical formula of the ternary precursor is Ni x Co y Mn z (OH)2, where 0.3≤x≤0.8, 0≤y≤0.3, 0≤z≤0.7, and x+y+z=1; And / or, the D50 of the ternary precursor is 3μm-6.5μm; And / or, the SSA of the ternary precursor is 7m. 2 / g-25m 2 / g.
4. A method for preparing a ternary precursor with continuously controllable particle size distribution width as described in any one of claims 1-3, characterized in that, include: A transition metal salt solution, an alkaline solution, and ammonia water are introduced into the base liquid A to carry out the first reaction and obtain the seed slurry. The seed slurry, transition metal salt solution, ammonia and alkaline solution are introduced into the bottom liquid B, and a second reaction is carried out in an oxygen-containing gas to obtain a lithium-rich manganese-based hydroxide precursor. The second reaction satisfies: ； Among them, L 晶种 L represents the theoretical flow rate of the seed slurry, in L / min. 盐 The flow rate of the transition metal salt solution is expressed in L / min; W 盐 M represents the molar concentration of a transition metal salt solution, in mol / L. 盐 W represents the molar molecular weight of the lithium-rich manganese-based hydroxide precursor, in g / mol. 晶种 R represents the solid content of the seed slurry, in g / L. 成品 D50 of the lithium-rich manganese-based hydroxide precursor, in μm; R 晶种 The D50 of the seed crystals in the seed slurry, in μm; In the second reaction process, the rotation speed is 2.5m / s-8m / s, the hourly feed volume of the transition metal salt solution is 4%-18% of the reactor volume, and the molar ratio of oxygen molecules in the oxygen-containing gas to Mn in the transition metal salt solution is 1:1.5-3. The flow rate of the seed slurry is 70%. L 晶种 -130% L 晶种 mL / min.
5. The method for preparing a ternary precursor with continuously controllable particle size distribution width according to claim 4, characterized in that, The temperature of the second reaction is 45-75℃; And / or, the second reaction is carried out in a reactor, the height of the bottom liquid B is up to the height of the overflow valve in the reactor, and after the particle size of the material in the second reaction reaches the preset particle size, the slurry discharged from the overflow port of the reactor is collected, and the slurry is aged, washed, dried and screened to obtain the lithium-rich manganese-based hydroxide precursor. And / or, the molar concentration of the transition metal salt solution is 1.8-2.2 mol / L; And / or, the solid content of the seed slurry is 200-500 g / L; And / or, the D50 of the seed crystals in the seed slurry is 2-3.6 μm.
6. The method for preparing a ternary precursor with continuously controllable particle size distribution width according to claim 4 or 5, characterized in that, The ammonia concentration in the substrate solution A is 3-12 g / L, and the pH is 11.5-12.
20. And / or, the temperature of the first reaction is 40-70℃, the pH value is reduced to 10.0-11.6 after 20-180 min, and the oxygen content is ≤3%; And / or, the primary particles in the seed crystal are coarse strips with a thickness of 60-200 nm; And / or, the ammonia concentration of the substrate B is 3-10 g / L, and the pH is 10.0-10.
70.
7. A positive electrode material, characterized in that, Includes the ternary precursor with continuously controllable particle size distribution width as described in any one of claims 1-3.
8. A lithium-ion battery, characterized in that, Includes the cathode material as described in claim 7.
9. An electrical appliance, characterized in that, Including the lithium-ion battery as described in claim 8.