Precursor for non-radial growth of surface primary particles, preparation method thereof, lithium-ion battery, cathode material thereof, and electricity-related device

Abstract

The present application provides a precursor with non-radial growth of primary particles on the surface, a preparation method thereof, a lithium-ion battery, a cathode material thereof, and an electricity-related device, relating to the field of lithium-ion batteries. The primary particles on the surface of the precursor are in the shape of scales and are inclined and stacked on the surface of the secondary particles in a non-radial direction. The preparation method includes: under the protection of an inert gas, introducing raw materials including a metal salt solution, a doped metal salt solution, a precipitating agent, and a complexing agent into a first bottom liquid to carry out a first reaction to obtain a seed slurry; introducing the seed slurry, the metal salt solution, the doped metal salt solution, the precipitating agent, and the complexing agent into a second bottom liquid to carry out a second reaction to obtain a precursor with non-radial growth of primary particles on the surface. The precursor with non-radial growth of primary particles on the surface provided by the present application has no fine powder on the surface of the secondary particle sphere, has strong compressive capacity, is not easily radially cracked, and is even less likely to be broken. While taking into account the battery capacity, the cycle performance is improved.

Description

Technical Field

[0001] The present application relates to the field of lithium-ion batteries, and particularly to a precursor with non-radial growth of primary particles on the surface, a preparation method thereof, a lithium-ion battery, a cathode material thereof, and an electricity-related device. Background Art

[0002] In recent years, lithium-ion batteries made of nickel-doped polyanode precursor materials have been widely used in fields such as power batteries and small batteries. High tap density, high capacity, long cycle life, and low cost are the inevitable development directions of future polyanode precursor material lithium-ion batteries. Medium-high nickel materials are cathode materials for high-capacity lithium-ion batteries developed in recent years and have the important advantage of high specific capacity. However, the higher the nickel content in the polyanode precursor material, the worse the stability and safety of the material. In addition, the optimization of the cost of lithium-ion battery materials is also the core manifestation of important competitiveness in the future.

[0003] Although in the preparation method of nickel-doped polyanode precursor materials, compared with the batch method, the continuous method is simpler in operation and lower in production cost; due to the high nickel content in the reaction system, the precipitation speed is faster, the residence time of the continuous process is shorter, it is easy to generate a fine and dense radial fine needle-like primary particle morphology and a secondary particle structure with fewer corresponding sectional pores, and problems such as cracked balls and fine powders are likely to occur. Eventually, although the prepared battery has a high specific capacity in terms of electrochemical performance, its cycle stability performance is poor and it is difficult to be practically applied on a large scale.

[0004] Therefore, developing medium-high nickel products with low cost and high cycle performance without reducing the specific capacity and their preparation methods is a problem that needs to be solved in this industry. Summary of the Invention

[0005] The purpose of the present application is to provide a precursor with non-radial growth of primary particles on the surface, a preparation method thereof, a lithium-ion battery, a cathode material thereof, and an electricity-related device to solve the above problems.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] A precursor with non-radial growth of primary particles on the surface, wherein the primary particles on the surface are scaly and are inclined and stacked on the surface of the secondary particles along a non-radial direction.

[0008] Preferably, the precursor satisfies at least one of the following conditions:

[0009] A. The precursor has pores inside;

[0010] Preferably, the porosity of the precursor is 2.5%-6.5%;

[0011] B. The average particle size D50 of the precursor is 10-20 μm;

[0012] Preferably, the average particle size D50 of the precursor is 10-15 μm;

[0013] C. The particle size distribution of the precursor (D90-D10) / D50 is 1.25-1.65;

[0014] D. The BET of the precursor is 10-20 m 2 / g;

[0015] E. The TD of the precursor is 2.0-2.5 g / cm 3 ;

[0016] F. The secondary particles of the precursor are spherical or quasi-spherical, and the average angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0°-60°;

[0017] Preferably, the average angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0°-45°;

[0018] G. The average aspect ratio of the primary particles on the surface of the precursor is 1.0-2.0;

[0019] H. The chemical general formula of the precursor is Ni a M 1-a (OH)2, 0.6 ≤ a < 1, and M is at least one of Co, Mn, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb or Sr.

[0020] Preferably, the precursor satisfies at least one of the following conditions:

[0021] I. The precursor has the half-peak width α of the (001) crystal plane corresponding to the diffraction angle 2θ = 19.2 ± 1° and the half-peak width β of the (101) crystal plane corresponding to the diffraction angle 2θ = 38.5 ± 1°, α and β are each independently 0.2-0.4, and β / α ≥ 1.0;

[0022] Preferably, the half-peak width α of the (001) crystal plane of the precursor is 0.254-0.270, and the half-peak width β of the (101) crystal plane of the precursor is 0.316-0.326;

[0023] J. The precursor has the peak intensity I 001 of the (001) crystal plane corresponding to the diffraction angle 2θ = 19.2 ± 1° and the peak intensity I 101 of the (101) crystal plane corresponding to the diffraction angle 2θ = 38.5 ± 1°, I 101 / I 001 is 0.5-0.8;

[0024] K. The chemical general formula of the precursor is Nia Al b X c (OH)₂, where X is Mn and / or Zr, a + b + c = 1, 0.6 ≤ a < 1, 0 ≤ b < 0.3, 0 ≤ c < 0.1;

[0025] Preferably, 0.9 ≤ a < 1, 0 ≤ b < 0.05, 0 ≤ c < 0.05;

[0026] More preferably, 0.95 ≤ a < 1.

[0027] This application also provides a preparation method of a precursor with non-radial growth of surface primary particles, including:

[0028] Under the protection of inert gas, raw materials including a metal salt solution, a doped metal salt solution, a precipitant, and a complexing agent are introduced into a first bottom liquid to carry out a first reaction to obtain a seed slurry;

[0029] Under the protection of inert gas, the seed slurry, the metal salt solution, the doped metal salt solution, the precipitant, and the complexing agent are introduced into a second bottom liquid to carry out a second reaction to obtain a precursor with non-radial growth of surface primary particles.

[0030] Preferably, the D50 of the seeds obtained from the first reaction is 2 - 8 μm;

[0031] Preferably, the hourly addition amount of the seeds is 0.05 wt% - 0.15 wt% of the hourly output;

[0032] Preferably, during the first reaction and the second reaction, the pH of the system is independently controlled to be 10.5 - 12.5;

[0033] Preferably, the ammonia concentration during the first reaction is controlled to be 1 - 17 g / L, and the ammonia concentration during the second reaction is controlled to be 10 - 17 g / L;

[0034] Preferably, during the first reaction and the second reaction, the reaction temperature is independently controlled to be 35 - 75 °C;

[0035] Preferably, during the first reaction and the second reaction, the stirring speed of the reaction is independently controlled to be 200 - 1200 r / min.

[0036] Preferably, the first bottom liquid and the second bottom liquid independently include water, a precipitant, and a complexing agent;

[0037] Preferably, the precipitant includes one or more of sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution, and the complexing agent includes one or more of ammonia water, ammonium bicarbonate solution, and ammonium carbonate solution;

[0038] Preferably, the pH of the first bottom solution is 11.5 - 12.5, and the ammonia concentration is 0.24 - 0.85 mol / L; the pH of the second bottom solution is 10.7 - 11.7, and the ammonia concentration is 0.6 - 0.9 mol / L;

[0039] Preferably, the concentrations of the sodium hydroxide solution and the ammonia water are each independently 2 - 20 mol / L.

[0040] Preferably, the metal salts in the metal salt solution include one or more of nickel salts, aluminum salts, manganese salts, and cobalt salts;

[0041] The doping metal salts in the doping metal salt solution include one or more of cobalt salts, titanium salts, zirconium salts, molybdenum salts, chromium salts, tungsten salts, boron salts, magnesium salts, barium salts, niobium salts, and strontium salts;

[0042] Preferably, the nickel salts include one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel chloride; the aluminum salts include one or more of aluminum sulfate, aluminum nitrate, aluminum acetate, and aluminum chloride; the manganese salts include one or more of manganese sulfate, manganese chloride, and manganese nitrate; the cobalt salts include one or more of cobalt sulfate, cobalt chloride, and cobalt nitrate;

[0043] Preferably, the zirconium salts include zirconium sulfate and / or zirconium nitrate;

[0044] Preferably, the metal salt solution further includes a buffer, and the buffer includes sodium citrate and / or trisodium citrate;

[0045] Preferably, the total concentration of metal ions in the doping metal salt solution is 1 - 5 mol / L.

[0046] Preferably, after the second reaction, it further includes: after solid-liquid separation, a filter residue and a filtrate are obtained. The filter residue is the wet material of the precursor. After the wet material of the precursor is subjected to alkali washing, water washing, drying, and screening to remove magnetism, the precursor is obtained, and the drying temperature is 60 - 200 °C.

[0047] This application also provides a cathode material for a lithium-ion battery, and its raw materials include a precursor with non-radial growth of surface primary particles;

[0048] Preferably, the cathode material for a lithium-ion battery has a peak intensity I of the (003) crystal plane corresponding to a diffraction angle 2θ = 18.5 ± 1° 003 and a peak intensity I of the (104) crystal plane corresponding to a diffraction angle 2θ = 44.0 ± 1° 104 , I 003 / I 104 > 1.2.

[0049] This application also provides a lithium-ion battery, and its raw materials include the cathode material for a lithium-ion battery.

[0050] The present application also provides an electricity-related device, including a lithium-ion battery.

[0051] Compared with the prior art, the beneficial effects of the present application include:

[0052] 1. For the precursor with non-radial growth of surface primary particles provided by the present application, the surface primary particles are scaly and inclinedly stacked on the surface of secondary particles along a non-radial direction. This non-radial structure is beneficial to improving the overall compressive capacity of secondary particles. Compared with secondary particles with radially distributed surface primary particles, they are not prone to radial cracking and are more difficult to break, improving the cycle stability performance of the material. In addition, the inclined stacking growth of surface primary particles is beneficial to improving the stress of material particles, avoiding cracks caused by the rapid deintercalation and insertion of lithium ions that damage the crystal structure, and improving the cycle stability performance of the material.

[0053] 2. Different from the conventional preparation process in which surface primary particles grow along the radial direction, to make surface primary particles grow along the radial direction, the preparation method of the precursor with non-radial growth of surface primary particles provided by the present application is prepared by a two-step reaction: first prepare seeds and then grow large particles. By controlling the system pH value, ammonia concentration, and stirring speed, the surface primary particles preferentially grow on the (001) crystal plane, realizing that the surface primary particles are scaly and inclinedly stacked along a non-radial direction, preventing cracks caused by internal stress caused by the radial growth of surface primary particles and affecting the cycle performance.

[0054] 3. The preparation method provided by the embodiments of the present application is a high-nickel continuous production process with a non-radial structure of surface primary particles. This preparation method uses seeds to avoid primary nucleation and can be continuously produced, generating secondary particles with a wide particle size distribution and surface primary particles with a scaly special morphology. It can effectively improve the fine powder with a dense and pore-free high-nickel structure and more primary nucleation of secondary particles under the conventional continuous process, and at the same time has certain pores, which is beneficial to the full contact of the battery electrolyte. The battery material prepared by this product, while taking into account the battery capacity, effectively improves the service life and cycle stability of the material.

[0055] 4. The lithium-ion battery cathode material, lithium-ion battery, and electricity-related device provided by the present application have good rate performance, high capacity, low battery operation power consumption, and good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope of the present application.

[0057] Figure 1Schematic diagrams of precursors with two different distribution patterns; among them, the left figure is a schematic diagram of the angle γ between the surface primary particles with a radial distribution of the secondary particles of the precursor and the tangent plane of the sphere of the secondary particles of the precursor; the right figure is a schematic diagram of the angle γ between the surface primary particles with a non-radial distribution of the secondary particles of the precursor and the tangent plane of the sphere of the secondary particles of the precursor;

[0058] Figure 2 SEM image of the precursor obtained in Example 1 at 1000 times magnification;

[0059] Figure 3 SEM image of the precursor obtained in Example 1 at 5000 times magnification;

[0060] Figure 4 SEM image of the precursor obtained in Example 1 at 10000 times magnification;

[0061] Figure 5 SEM image of the precursor obtained in Example 2 at 1000 times magnification;

[0062] Figure 6 SEM image of the precursor obtained in Example 2 at 5000 times magnification;

[0063] Figure 7 SEM image of the precursor obtained in Example 2 at 10000 times magnification;

[0064] Figure 8 SEM image of the precursor obtained in Comparative Example 1 at 1000 times magnification;

[0065] Figure 9 SEM image of the precursor obtained in Comparative Example 1 at 5000 times magnification;

[0066] Figure 10 SEM image of the precursor obtained in Comparative Example 1 at 10000 times magnification;

[0067] Figure 11 Cross-sectional comparison diagram of the precursors obtained in Example 1 and Comparative Example 1;

[0068] Figure 12 SEM image of the precursor obtained in Comparative Example 2 at 1000 times magnification;

[0069] Figure 13 SEM image of the precursor obtained in Comparative Example 2 at 5000 times magnification;

[0070] Figure 14 SEM image of the precursor obtained in Comparative Example 2 at 10000 times magnification;

[0071] Figure 15 Schematic diagram of the cycling performance of the coin cell prepared from the material obtained in Example 1;

[0072] Figure 16Schematic diagram of the cycling performance of the coin cell prepared from the material obtained in Example 2;

[0073] Figure 17 Schematic diagram of the cycling performance of the coin cell prepared from the material obtained in Comparative Example 1;

[0074] Figure 18 Schematic diagram of the cycling performance of the coin cell prepared from the material obtained in Comparative Example 2. Detailed Description of the Invention

[0075] As used herein, the terms:

[0076] "prepared from" is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a listed element(s) is not necessarily limited to those element(s), but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0077] The connecting phrase "consisting of" excludes any unrecited element, step, or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0078] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any combination of any upper range limit or preferred value with any lower range limit or preferred value, whether or not the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0079] In these examples, unless otherwise specified, parts and percentages are by mass.

[0080] "and / or" is used to indicate that either or both of the stated circumstances may occur, e.g., A and / or B includes (A and B) and (A or B).

[0081] A precursor with non-radial growth of surface primary particles, where the surface primary particles are scaly and are stacked obliquely in a non-radial direction on the surface of secondary particles.

[0082] As Figure 1 shown, the left figure is a schematic diagram of the angle γ between the surface primary particles with radial distribution of the secondary particles of the precursor and the tangent plane of the secondary particles of the precursor; the average angle γ is 80° - 90°;

[0083] The right figure is a schematic diagram of the angle γ between the surface primary particles with non-radial distribution of the spherical secondary particles of the precursor and the tangent plane of the spherical secondary particles of the precursor; its average angle γ is 0° - 60°.

[0084] In an optional embodiment, the interior of the precursor with non-radial growth of surface primary particles has pores;

[0085] From the perspective of improving cracking: the inclined stacking growth of surface primary particles is beneficial to improving the stress of material particles, avoiding cracks caused by the rapid deintercalation and insertion of lithium ions that damage the crystal structure, and improving the cycle stability performance of the material. In addition, when the surface primary particles grow radially, most of the force applied to the secondary particles can only be transmitted to the primary particles in the radial direction in contact with the force, and the pressure-bearing performance is poor; while the non-radially distributed surface primary particles can transmit the force to adjacent primary particles, with good pressure-bearing performance, and the secondary particles are not easily broken when compressed.

[0086] The pores inside the precursor are small round holes, rather than irregular large pores.

[0087] It should be noted that the "uniform distribution" referred to here is relative to irregular large pores.

[0088] This precursor product has no fine powder, and the prepared cathode material has good surface flatness, which can effectively reduce the operating power consumption of the battery and improve the safety of the battery.

[0089] In an optional embodiment, the porosity of the precursor with non-radial growth of surface primary particles is 2.5% - 6.5%;

[0090] Optionally, the porosity of the precursor with non-radial growth of surface primary particles can be 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or any value between 2.5% - 6.5%;

[0091] In an optional embodiment, the average particle size D50 of the precursor with non-radial growth of surface primary particles is 10 - 20 μm; preferably, the average particle size D50 of the precursor with non-radial growth of surface primary particles is 10 - 15 μm;

[0092] Optionally, the average particle size D50 of the precursor with non-radial growth of surface primary particles can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or any value between 10 - 20 μm;

[0093] In an optional embodiment, the particle size distribution (D90 - D10) / D50 of the precursor with non-radial growth of surface primary particles is 1.25 - 1.65;

[0094] Optionally, the particle size distribution (D90 - D10) / D50 of the precursor with non-radial growth of surface primary particles can be 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65 or any value between 1.25 - 1.65;

[0095] In an optional embodiment, the BET of the precursor with non-radial growth of surface primary particles is 10 - 20 m 2 / g;

[0096] Optionally, the BET of the precursor with non-radial growth of surface primary particles can be 10 m 2 / g, 11 m 2 / g, 12 m 2 / g, 13 m 2 / g, 14 m 2 / g, 15 m 2 / g, 16 m 2 / g, 17 m 2 / g, 18 m 2 / g, 19 m 2 / g, 20 m 2 / g or any value between 10 - 20 m 2 / g;

[0097] In an optional embodiment, the TD of the precursor with non-radial growth of surface primary particles is 2.0 - 2.5 g / cm 3 ;

[0098] Optionally, the TD of the precursor with non-radial growth of surface primary particles can be 2.0 g / cm 3 , 2.1 g / cm 3 , 2.2 g / cm 3 , 2.3 g / cm 3 , 2.4 g / cm 3 , 2.5 g / cm 3 or any value between 2.0 - 2.5 g / cm 3 ;

[0099] The particle size distribution of the precursor is relatively wide, which can increase the packing density of the cathode active material in the cathode, thereby increasing the energy density of the secondary battery using the cathode active material.

[0100] In an alternative embodiment, the secondary particles of the precursor are spherical or quasi-spherical; and the average angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0°-60°;

[0101] In a preferred embodiment, the average angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0°-45°;

[0102] Optionally, the average angle γ can be 0°, 10°, 20°, 30°, 40°, 45°, 50°, 60° or any value between 0°-60°;

[0103] The primary particles on the surface of the precursor of the present invention are flaky and are inclined and stacked on the surface of the secondary particles along a non-radial direction. Each primary particle on the surface of the sphere of the secondary particles has an angle γ with the tangent plane of the sphere of the secondary particles of the precursor. Generally, the angle γ between the primary particles on the surface and the tangent plane of the sphere of the secondary particles of the precursor can be obtained by scanning electron microscopy. The average angle γ between the primary particles on the surface and the tangent plane of the sphere of the secondary particles of the precursor is the average value of the angles γ of 30 primary particles on the surface with higher clarity and integrity in the same electron micrograph (for example, the SEM micrograph with a magnification of 10,000 times in the examples of the present invention) with the tangent plane of the sphere of the secondary particles of the precursor.

[0104] In an alternative embodiment, the average aspect ratio of the primary particles on the surface is 1.0-2.0;

[0105] Optionally, the average aspect ratio of the primary particles on the surface can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or any value between 1.0-2.0;

[0106] The primary particles on the surface of the precursor of the present invention are flaky and are inclined and stacked on the surface of the secondary particles along a non-radial direction. Each primary particle on the surface of the sphere of the secondary particles has a longest particle size (length) and a shortest particle size (width). Generally, the length and width of the primary particles can be statistically obtained by scanning electron microscopy and then the aspect ratio can be calculated. The average aspect ratio of the primary particles on the surface is the average value of the aspect ratios of 30 primary particles with higher clarity and integrity in the same electron micrograph (the SEM micrograph with a magnification of 10,000 times in the examples of the present invention).

[0107] In an alternative embodiment, the chemical general formula of the precursor is Ni a M 1-a(OH)2, 0.6 ≤ a < 1, and M is at least one of Co, Mn, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb, or Sr.

[0108] Optionally, a can take values of 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or any value greater than or equal to 0.6 and less than 1.

[0109] In an alternative embodiment, the precursor has a full width at half maximum α of the (001) crystal plane corresponding to a diffraction angle 2θ = 19.2 ± 1°, and a full width at half maximum β of the (101) crystal plane corresponding to a diffraction angle 2θ = 38.5 ± 1°. α and β are each independently 0.2 - 0.4, and β / α ≥ 1.0;

[0110] Optionally, α and β can each independently be 0.20, 0.25, 0.3, 0.35, 0.40, or any value between 0.2 - 0.4, and β / α ≥ 1.0;

[0111] In an alternative embodiment, the full width at half maximum α of the (001) crystal plane of the precursor is 0.254 - 0.270, and the full width at half maximum β of the (101) crystal plane of the precursor is 0.316 - 0.326;

[0112] Optionally, the full width at half maximum α of the (001) crystal plane of the precursor can be 0.254, 0.255, 0.260, 0.265, 0.270, or any value between 0.254 - 0.270, and the full width at half maximum β of the (101) crystal plane of the precursor can be 0.316, 0.317, 0.318, 0.319, 0.320, 0.321, 0.322, 0.323, 0.324, 0.325, 0.326, or any value between 0.316 - 0.326;

[0113] In an alternative embodiment, the precursor has a peak intensity I of the (001) crystal plane corresponding to a diffraction angle 2θ = 19.2 ± 1° 001 and a peak intensity I of the (101) crystal plane corresponding to a diffraction angle 2θ = 38.5 ± 1° 101 , I 101 / I 001 is 0.5 - 0.8;

[0114] Optionally, the peak intensity ratio I 101 / I 001 may be 0.5, 0.6, 0.7, 0.8 or any value between 0.5 and 0.8;

[0115] The above XRD parameters indicate that the precursor has a high diffraction intensity on the (001) plane, preferentially grows on the (001) plane, and the (001) plane has good crystallinity.

[0116] In an optional embodiment, the chemical general formula of the precursor with non-radial growth of surface primary particles is Ni a Al b X c (OH)2, where X is Mn and / or Zr, a + b + c = 1, 0.6 ≤ a < 1, 0 ≤ b < 0.3, 0 ≤ c < 0.1; preferably, 0.9 ≤ a < 1, 0 ≤ b < 0.05, 0 ≤ c < 0.05; more preferably, 0.95 ≤ a < 1.

[0117] Optionally, a may take values of 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99 or any value greater than or equal to 0.6 and less than 1;

[0118] b can be 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.020, 0.021, 0.022, 0.023, 0.024, 0.025, 0.026, 0.027, 0.028, 0.029, 0.030, 0.031, 0.032, 0.033, 0.034, 0.035, 0.036, 0.037, 0.038, 0.039, 0.040, 0.041, 0.042, 0.043, 0.044, 0.045, 0.046, 0.047, 0.048, 0.049, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.295 or any value greater than or equal to 0 and less than 0.3;

[0119] c can be 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.020, 0.021, 0.022, 0.023, 0.024, 0.025, 0.026, 0.027, 0.028, 0.029, 0.030, 0.031, 0.032, 0.033, 0.034, 0.035, 0.036, 0.037, 0.038, 0.039, 0.040, 0.041, 0.042, 0.043, 0.044, 0.045, 0.046, 0.047, 0.048, 0.049, 0.05, 0.06, 0.07, 0.08, 0.09, 0.095 or any value greater than or equal to 0 and less than 0.1.

[0120] The precursor has a high nickel content, a wide particle size distribution and good particle sphericity. The prepared cathode material particles have a high density and good surface flatness, with high capacity and can effectively reduce the operating power consumption of the battery and improve the safety of the battery.

[0121] The higher the Ni content, the more electrons are transferred and the greater the capacity accordingly.

[0122] The present application also provides a method for preparing a precursor with non-radial growth of surface primary particles, including:

[0123] Under the protection of an inert gas, raw materials including a metal salt solution, a doped metal salt solution, a precipitant, and a complexing agent are introduced into a first bottom liquid, and a first reaction is carried out to obtain a seed slurry;

[0124] Under the protection of an inert gas, the seed slurry, the metal salt solution, the doped metal salt solution, the precipitant, and the complexing agent are introduced into a second bottom liquid, and a second reaction is carried out to obtain a precursor with non-radial growth of surface primary particles.

[0125] In an optional embodiment, the D50 of the seeds obtained from the first reaction is 2 - 8 μm;

[0126] Optionally, the D50 of the seeds can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or any value between 2 - 8 μm;

[0127] In an optional embodiment, the hourly addition amount of the seeds is 0.05 wt% - 0.15 w% of the hourly output;

[0128] Herein, the "output" refers to the weight of the precursor product obtained within a certain period of time. The hourly addition amount of the seeds is dynamically adjusted according to the particle size D50 of the discharged product.

[0129] Optionally, the hourly addition amount of the seeds can be 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.10 wt%, 0.11 wt%, 0.12 wt%, 0.13 wt%, 0.14 wt%, 0.15 wt%, or any value between 0.05 wt% - 0.15 wt%;

[0130] During the first reaction and the second reaction, the reaction pH is independently controlled to be 10.5 - 12.5;

[0131] Optionally, during the first reaction and the second reaction, the system pH can be independently controlled to be 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, or any value between 10.5 - 12.5;

[0132] Control the ammonia concentration in the first reaction process to be 1 - 17 g / L, and control the ammonia concentration in the second reaction process to be 10 - 17 g / L;

[0133] Optionally, during the first reaction, the ammonia concentration in the control system can be 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, or any value between 1 - 17 g / L; during the second reaction, the ammonia concentration in the control system can be 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, or any value between 10 - 17 g / L.

[0134] During the first reaction and the second reaction, the reaction temperatures are independently controlled to be 35 - 75 °C respectively.

[0135] Optionally, during the first reaction and the second reaction, the reaction temperatures can be independently 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, or any value between 35 - 75 °C respectively.

[0136] During the first reaction and the second reaction, the stirring speeds of the reactions are independently controlled to be 200 - 1200 r / min.

[0137] Optionally, during the first reaction and the second reaction, the stirring speeds of the reactions can be independently 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min, or any value between 200 - 1200 r / min respectively.

[0138] The first bottom liquid and the second bottom liquid independently include water, a precipitant, and a complexing agent.

[0139] In an optional embodiment, the precipitant includes one or more of sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution, and the complexing agent includes one or more of ammonia water, ammonium bicarbonate solution, and ammonium carbonate solution.

[0140] In an optional embodiment, the pH of the first bottom liquid is 11.5 - 12.5, and the ammonia concentration is 0.24 - 0.85 mol / L; the pH of the second bottom liquid is 10.7 - 11.7, and the ammonia concentration is 0.6 - 0.9 mol / L.

[0141] Optionally, the pH of the first bottom solution can be 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5 or any value between 11.5 and 12.5, and the ammonia concentration can be 0.24 mol / L, 0.25 mol / L, 0.30 mol / L, 0.35 mol / L, 0.40 mol / L, 0.45 mol / L, 0.50 mol / L, 0.55 mol / L, 0.60 mol / L, 0.65 mol / L, 0.70 mol / L, 0.75 mol / L, 0.80 mol / L, 0.85 mol / L or any value between 0.24 and 0.85 mol / L; the pH of the second bottom solution can be 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7 or any value between 10.7 and 11.7; the ammonia concentration can be 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L or any value between 0.6 and 0.9 mol / L;

[0142] In an optional embodiment, the concentrations of the precipitating agent and the complexing agent are each independently 2 - 20 mol / L.

[0143] Optionally, the concentrations of the sodium hydroxide solution and the ammonia water can each independently be 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L, 13 mol / L, 14 mol / L, 15 mol / L, 16 mol / L, 17 mol / L, 18 mol / L, 19 mol / L, 20 mol / L or any value between 2 and 20 mol / L.

[0144] In an optional embodiment, the metal salt in the metal salt solution includes one or more of nickel salts, aluminum salts, manganese salts, and cobalt salts;

[0145] The doped metal salt in the doped metal salt solution includes one or more of cobalt salts, titanium salts, zirconium salts, molybdenum salts, chromium salts, tungsten salts, boron salts, magnesium salts, barium salts, niobium salts, and strontium salts;

[0146] In an optional embodiment, the nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel chloride, and the aluminum salt includes one or more of aluminum sulfate, aluminum nitrate, aluminum acetate, and aluminum chloride;

[0147] The manganese salt includes one or more of manganese sulfate, manganese chloride, and manganese nitrate; the cobalt salt includes one or more of cobalt sulfate, cobalt chloride, and cobalt nitrate;

[0148] In an alternative embodiment, the zirconium salt includes zirconium sulfate and / or zirconium nitrate;

[0149] In an alternative embodiment, the doped metal salt solution further includes a buffer, and the buffer includes sodium citrate and / or trisodium citrate;

[0150] In an alternative embodiment, the total concentration of metal ions in the metal salt solution is 1-5 mol / L.

[0151] Optionally, the total concentration of metal ions in the metal salt solution can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L or any value between 1-5 mol / L.

[0152] In an alternative embodiment, after the second reaction, it further includes: after solid-liquid separation, a filter residue and a filtrate are obtained. The filter residue is the wet material of the precursor. The wet material of the precursor is subjected to alkali washing, water washing, drying, screening and demagnetization to obtain the precursor, and the drying temperature is 60-200 °C.

[0153] Through process control, the precursor has no obvious core-shell structure, and the material ratio, porosity, etc. at each position are all the same. Among them, the seed crystal is a small particle with a good sphericity.

[0154] In an alternative embodiment, after the second reaction, it further includes: after solid-liquid separation, a filter residue and a filtrate are obtained. The filter residue is the wet material of the precursor. The wet material of the precursor is subjected to alkali washing, water washing, drying, screening and demagnetization to obtain the precursor, and the drying temperature is 60-200 °C.

[0155] Optionally, the drying temperature can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C or any value between 60-200 °C.

[0156] Compared with the conventional continuous preparation of the precursor, the present invention adds the seed method on the basis of continuous preparation. When preparing the precursor, a seed core is first prepared, which helps to avoid the problem of fine powder generated by the small particle size during the initial nucleation in the reaction and not reaching the target particle size. And by controlling the size and quantity of the seeds, the D50 size and the stability of the particle size distribution coefficient of the second reaction product are controlled. A special doping salt is selected, and appropriate pH value, ammonia concentration, and stirring speed are selected during the reaction, especially during the second reaction, so that the precipitate particles preferentially grow on the (001) crystal plane, and the surface primary particles are scaly and stacked on the surface of the secondary particles along the non-radial direction, avoiding the surface primary particles from becoming dot-shaped, needle-shaped or disordered flaky structures stacked on the surface of the secondary particles. This structure helps to improve a series of problems in the battery caused by the appearance of fine powder on the surface of the secondary particles in the product and the problem of easy cracking caused by the stress action of the radial structure.

[0157] The presence of fine powder affects the self-discharge of the battery in two aspects, that is, it increases the side reactions and micro-shorts in the battery, and as the fine powder increases, its influence becomes more serious. In addition, the presence of fine powder will deteriorate the high-temperature storage performance of the battery, causing the battery to decay in capacity and increase in internal resistance during storage, and accompanied by phenomena such as bloating, affecting the cycle performance of the material. Therefore, in actual production, it is necessary to strictly control the particle size distribution of the secondary particles of the material to avoid the appearance of fine powder.

[0158] This application also provides a cathode material for a lithium-ion battery, the raw materials of which include a precursor with non-radial growth of surface primary particles;

[0159] In an optional embodiment, the cathode material for a lithium-ion battery has a peak intensity I of the (003) crystal plane corresponding to a diffraction angle 2θ = 18.5 ± 1° 003 and a peak intensity ratio I of the (104) crystal plane corresponding to a diffraction angle 2θ = 44.0 ± 1° 104 , I 003 / I 104 > 1.2.

[0160] I 003 / I 104 > 1.2, the Li + / Ni 2+ mixing disorder is relatively low, and the layered structure is relatively good (the insertion and extraction of lithium ions are based on the microscopic layered structure of the material). Excessive lithium-nickel mixing disorder in the cathode material will cause blockage of the channels for lithium-ion insertion and extraction, resulting in a significant reduction in the specific capacity of the material.

[0161] This application also provides a lithium-ion battery, the raw materials of which include a cathode material for a lithium-ion battery.

[0162] This application also provides an electricity-related device, including a lithium-ion battery.

[0163] The implementation solutions of the present application will be described in detail below in conjunction with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0164] Example 1

[0165] This example provides a precursor with the chemical formula Ni 0.985 Al 0.011 Zr 0.004 (OH)2, the primary particles on its surface are scaly and are stacked obliquely along the non-radial direction on the surface of the secondary particles. Its preparation method is as follows:

[0166] 1. Solution preparation:

[0167] Accurately weigh NiSO4·6H2O and Al2(SO4)3 salts according to the molar ratio of nickel to aluminum of 99.9:0.01, and add water to prepare a metal salt solution of nickel-aluminum sulfate with a total metal molar concentration of 2 mol / L; weigh zirconium sulfate and sodium citrate, and add water to prepare a doped metal salt solution of zirconium sulfate-sodium citrate with a zirconium concentration of 3.6 g / L and a sodium citrate concentration of 5.6 g / L; prepare a precipitating agent as a 10 mol / L sodium hydroxide solution; prepare a complexing agent as an 8 mol / L ammonia water solution.

[0168] 2. First reaction (precipitation to form seed crystal nuclei):

[0169] Under nitrogen protection, add water to the reaction kettle (Ⅰ), and add sodium hydroxide solution and ammonia water solution to prepare a first bottom liquid with a pH value of 12.0 and an ammonia concentration of 0.24 mol / L. Heat the temperature in the kettle to 60 °C, control the stirring speed at 694 r / min. After the conditions are reached, simultaneously introduce the metal salt solution of nickel-aluminum sulfate, the doped metal salt solution of zirconium sulfate-sodium citrate, sodium hydroxide solution, and ammonia water, and control the pH value during the first reaction to be 11.9 ± 0.2 and the ammonia water concentration to be 4.0 ± 0.5 g / L, control the amount of reaction nucleation, and continuously feed materials until the particle size D50 of the seed slurry is stably reached at 3.0 μm ± 0.5 μm, then start to receive the seed slurry, store it, and turn on nitrogen protection.

[0170] 3. Second reaction (preparation of continuous large-particle products):

[0171] Under nitrogen protection and under stirring conditions of 387 r / min, pure water, ammonia water, and sodium hydroxide are added to the reaction kettle (II) to prepare a second bottom solution with an ammonia concentration of 0.88 mol / L and a pH of 10.7. The temperature inside the kettle is raised to 60 °C, and then a metal salt solution of nickel aluminum sulfate, a doped metal salt solution of zirconium sulfate - sodium citrate, an ammonia water solution, a sodium hydroxide solution, and a seed slurry are simultaneously introduced. The hourly addition amount of the seeds is 0.05 wt% - 0.15 wt% of the hourly output; during the second reaction process, the pH value is controlled to be 10.7 ± 0.2 and the ammonia water concentration is 15.0 ± 0.5 g / L until the D50 is stably controlled at 13.5 ± 0.5 μm, and the material is collected.

[0172] 4. Post-treatment:

[0173] The material is centrifuged to obtain the supernatant and the filtrate. The supernatant is washed with dilute sodium hydroxide solution and pure water until the Na and S contents are less than 300 ppm and 2000 ppm respectively; the washed supernatant is dried at 120 °C for 16 hours; after sieving through a 300-mesh sieve and removing magnetism, a high-nickel-doped precursor with a continuous preparation, D50 of 13.5 ± 0.5 μm, and a wide particle size distribution is obtained. The SEM spectra are as Figure 2 , Figure 3 , Figure 4 (1000 times, 5000 times, and 10000 times) shown, and the XRD diffraction results are shown in Table 1.

[0174] Example 2

[0175] This example provides a precursor with the chemical formula Ni 0.99 Zr 0.01 (OH)2, the primary particles on its surface are scaly and are inclined and stacked on the surface of the secondary particles in a non-radial direction. Its preparation method is as follows:

[0176] 1. Solution preparation:

[0177] Weigh nickel sulfate salt and add pure water to dissolve it to prepare a metal salt solution with a nickel sulfate concentration of 2 mol / L; weigh sodium citrate and water and add them to zirconium sulfate, and add water to prepare a doped metal salt solution of zirconium sulfate - sodium citrate with a zirconium concentration of 3.65 g / L and a sodium citrate concentration of 5.6 g / L; prepare a sodium hydroxide solution with a concentration of 10 mol / L as the precipitant; prepare an ammonia water solution with a concentration of 8 mol / L as the complexing agent.

[0178] 2. First reaction (co-precipitation to form seed nuclei):

[0179] Under neon protection, water is added to the reaction kettle (Ⅰ), and a sodium hydroxide solution and an ammonia water solution are added to prepare a first bottom liquid with a pH value of 12.0 and an ammonia concentration of 0.24 mol / L. The temperature in the kettle is raised to 65 °C, and the stirring speed is controlled at 694 r / min. After the conditions are reached, a metal salt solution of nickel sulfate, a doped metal salt solution of zirconium sulfate - sodium citrate, sodium hydroxide, and ammonia water are simultaneously introduced, and the pH value during the first reaction process is controlled at 11.9 ± 0.2, and the ammonia water concentration is 4.0 ± 0.5 g / L. The amount of reaction nucleation is controlled until the particle size D50 of the seed slurry stably reaches 3.5 ± 0.5 μm, then continuous feeding starts, the seed slurry is started to be fed and preserved, and nitrogen protection is turned on.

[0180] 3. Second reaction (preparation of continuous large - particle products):

[0181] Under neon protection, pure water, ammonia water, and sodium hydroxide are added to the reaction kettle (Ⅱ) under stirring conditions of 387 r / min to prepare a second bottom liquid with an ammonia concentration of 0.6 mol / L and a pH of 11.6. The temperature in the kettle is raised to 65 °C, and then a metal salt solution of nickel sulfate, a doped metal salt solution of zirconium sulfate - sodium citrate, an ammonia water solution, a sodium hydroxide solution, and a seed slurry are simultaneously introduced. The addition amount of the seed per hour is 0.05 wt% - 0.15 wt% of the hourly output; the pH value during the second reaction process is controlled at 11.6 ± 0.2, and the ammonia water concentration is 10.5 ± 0.5 g / L until D50 is stably controlled at 13.5 ± 0.5 μm, and the materials are collected.

[0182] 4. Post - treatment:

[0183] The materials are centrifuged to obtain the filter residue and the filtrate. The filter residue is washed with a dilute sodium hydroxide solution and pure water until the Na and S contents are less than 300 ppm and 2000 ppm respectively; the washed filter residue is dried at 105 °C for 24 hours; after screening through a 300 - mesh sieve and removing magnetism, a high - nickel - doped precursor with a continuous preparation, D50 of 13.5 ± 0.5 μm, and a wide particle size distribution is obtained. The SEM spectra are as shown in Figure 5 、 Figure 6 、 Figure 7 (1000 - fold, 5000 - fold, and 10000 - fold), and the XRD diffraction results are shown in Table 1.

[0184] Example 3

[0185] This example provides a precursor with the chemical formula Ni 0.95 Al 0.03 Mn 0.02 (OH)2, the primary particles on its surface are scaly and are stacked on the surface of the secondary particles in a non - radial inclined direction. Its preparation method is as follows:

[0186] 1. Solution preparation:

[0187] Accurately weigh nickel sulfate, aluminum sulfate, and manganese sulfate in a molar ratio of nickel, aluminum, and manganese of 95:3:2, and add water to prepare a metal salt solution of nickel, manganese, and aluminum sulfate with a concentration of 2 mol / L; prepare a precipitating agent as a 10 mol / L sodium hydroxide solution; prepare a complexing agent as an 8 mol / L ammonia water solution.

[0188] 2. First reaction (co-precipitation to form seed crystal nuclei):

[0189] Under nitrogen protection, add water to the reaction kettle (Ⅰ), add sodium hydroxide solution and ammonia water solution to prepare a first bottom liquid with a pH value of 12.0 and an ammonia concentration of 0.6 mol / L. Heat the temperature in the kettle to 55 °C, control the stirring speed at 694 r / min. After the conditions are reached, simultaneously introduce the metal salt solution of nickel, manganese, and aluminum sulfate, sodium hydroxide, and ammonia water, and control the pH value of the first reaction system to be 12.0 ± 0.2 and the ammonia water concentration to be 4.0 ± 0.5 g / L. Control the amount of nuclei formation in the reaction until the particle size D50 of the seed slurry is stably reached at 3.0 ± 0.5 μm, then continuously receive the material, start receiving the seed slurry, store it, and turn on nitrogen protection.

[0190] 3. Second reaction (preparing continuous large-particle products):

[0191] Under nitrogen protection, add pure water, ammonia water, and sodium hydroxide to the reaction kettle (Ⅱ) under stirring conditions of 223 r / min to prepare a second bottom liquid with an ammonia concentration of 0.85 mol / L and a pH of 11.4. Heat the temperature in the kettle to 55 °C, and then simultaneously introduce the metal salt solution of nickel, manganese, and aluminum sulfate, ammonia water solution, sodium hydroxide solution, and seed slurry. The hourly addition amount of the seed is 0.05 wt% - 0.15 wt% of the hourly output; control the pH value during the second reaction to be 11.4 ± 0.2 and the ammonia water concentration to be 14.5 ± 0.5 g / L until D50 is stably controlled at 11.5 ± 0.5 μm, and collect the material.

[0192] 4. Post-treatment:

[0193] Centrifuge the material to obtain the supernatant and the filtrate. Wash the supernatant with dilute sodium hydroxide solution and pure water until the Na and S contents are less than 300 ppm and 2000 ppm respectively; dry the washed supernatant at 150 °C for 10 hours; sieve through a 300-mesh sieve and demagnetize to obtain a continuously prepared high-nickel-doped precursor with a D50 of 11.5 ± 0.5 μm and a wide particle size distribution.

[0194] Example 4

[0195] This example provides a chemical formula of Ni 0.98 Al 0.02(OH)₂ precursor, with the primary particles on its surface being scaly and inclined to stack along a non-radial direction on the surface of the secondary particles. The preparation method is as follows:

[0196] 1. Solution preparation:

[0197] Accurately weigh nickel sulfate and aluminum sulfate salts according to the molar ratio of nickel to aluminum of 98:2, and add water to prepare a metal salt solution of nickel-aluminum sulfate with a concentration of 2 mol / L; prepare a precipitant as a 10 mol / L sodium hydroxide solution; prepare a complexing agent as an 8 mol / L ammonia water solution.

[0198] 2. First reaction (co-precipitation to form seed crystal nuclei):

[0199] Under nitrogen protection, add water to the reaction kettle (Ⅰ), add sodium hydroxide solution and ammonia water solution to prepare a first bottom liquid with a pH value of 12.0 and an ammonia concentration of 0.6 mol / L. Heat the temperature in the kettle to 55 °C, control the stirring speed at 694 r / min. After the conditions are reached, simultaneously introduce the metal salt solution of nickel-aluminum sulfate, sodium hydroxide, and ammonia water, and control the pH value of the first reaction system to be 12.0 ± 0.2 and the ammonia water concentration to be 4.0 ± 0.5 g / L. Control the amount of reaction nucleation until the particle size D50 of the seed slurry is stably reached at 3.0 ± 0.5 μm, then continuously receive the material, start receiving the seed slurry, and preserve it, and turn on nitrogen protection.

[0200] 3. Second reaction (preparation of continuous large-particle products):

[0201] Under nitrogen protection, add pure water, ammonia water, and sodium hydroxide to the reaction kettle (Ⅱ) under the stirring condition of 223 r / min to prepare a second bottom liquid with an ammonia concentration of 0.9 mol / L and a pH of 11.5. Heat the temperature in the kettle to 55 °C, and then simultaneously introduce the metal salt solution of nickel-aluminum sulfate, ammonia water solution, sodium hydroxide solution, and seed slurry. The hourly addition amount of the seed is 0.05 wt% - 0.15 wt% of the hourly output; control the pH value during the second reaction to be 11.5 ± 0.2 and the ammonia water concentration to be 15.2 ± 0.5 g / L until D50 is stably controlled at 13.5 ± 0.5 μm, and collect the material.

[0202] 4. Post-treatment:

[0203] Centrifuge the material to obtain the filter residue and the filtrate. Wash the filter residue with dilute sodium hydroxide solution and pure water until the contents of Na and S are less than 300 ppm and 2000 ppm respectively; dry the washed filter residue at 150 °C for 10 hours; sieve through a 300-mesh sieve and remove magnetism, then obtain the continuously prepared high-nickel-doped precursor with D50 of 13.5 ± 0.5 μm and a wide particle size distribution, and it can be sealed and preserved.

[0204] Comparative Example 1

[0205] This comparative example provides a high-nickel doped precursor with the chemical formula Ni 0.985 Al 0.011 Zr 0.004 (OH)₂; the primary particles on its surface are needle-shaped and distributed radially. Its preparation method is as follows:

[0206] 1. Solution preparation is the same as in Example 1;

[0207] 2. Precipitation reaction (preparing continuous large-particle products):

[0208] Under nitrogen protection, in the reaction kettle (Ⅱ), pure water, ammonia water, and sodium hydroxide are added under stirring at 387 r / min, and the ammonia concentration is adjusted to 0.6 mol / L and the pH is adjusted to 10.7 to prepare the reaction bottom liquid. The temperature in the kettle is raised to 60 °C, and the stirring speed is controlled at 694 r / min. Then, a metal salt solution of nickel aluminum sulfate, a doped metal salt solution of zirconium sulfate-sodium citrate, an ammonia water solution, and a sodium hydroxide solution are simultaneously introduced; and the pH value of the reaction system is controlled at 10.7 ± 0.2, and the ammonia water concentration is 9.3 ± 0.5 g / L. After the reaction until D50 is stably controlled at 13.5 ± 0.5 μm, the barrel is changed to receive the material, and the product is continuously and stably produced until sufficient material is received, and then the reaction is stopped.

[0209] 4. Post-treatment is the same as in Example 1, and a continuous high-nickel doped precursor with a needle-shaped radial wide particle size distribution with D50 of 13.5 ± 0.5 μm is obtained. Its SEM images are as shown in Figure 8 、 Figure 9 、 Figure 10 (1000 times, 5000 times, and 10000 times). The cross-sectional comparison diagrams of the precursors obtained in Example 1 (left figure) and Comparative Example 1 (right figure) are as shown in Figure 11 . The XRD diffraction results are shown in Table 1.

[0210] Compared with Example 1, Comparative Example 1 is a non-seed process, and the ammonia concentration value of the reaction bottom liquid, the stirring frequency, and the ammonia water concentration during the reaction process are changed.

[0211] Comparative Example 2

[0212] This comparative example provides a high-nickel doped precursor with the chemical formula Ni 0.98 Al 0.02 (OH)₂; the primary particles on its surface are needle-shaped and distributed radially. Its preparation method is as follows:

[0213] 1. Solution preparation is the same as in Example 4.

[0214] 2. Precipitation reaction (preparing continuous large-particle products):

[0215] Under nitrogen protection, in reactor (II), pure water, ammonia water and sodium hydroxide were added under stirring at 387 r / min to prepare a reaction bottom solution with an ammonia concentration of 0.6 mol / L and a pH of 11.2. The temperature in the reactor was raised to 55 °C, and the stirring speed was controlled at 694 r / min. Then, a metal salt solution of nickel-aluminum sulfate, an ammonia water solution, and a sodium hydroxide solution were simultaneously introduced; and the pH value of the reaction system was controlled at 11.2 ± 0.2, and the ammonia water concentration was 9.5 ± 0.2 g / L. The reaction was continued until D50 was stably controlled at 13.5 ± 0.5 μm, and the material was collected.

[0216] 3. The post-treatment was the same as in Example 4 to obtain a continuously prepared high-nickel doped precursor with a D50 of 13.5 ± 0.5 μm and a wide particle size distribution. The SEM spectra are as Figure 12 、 Figure 13 、 Figure 14 (1000 times, 5000 times and 10000 times) shown.

[0217] Compared with Example 4, Comparative Example 2 was a non-seed process, and the stirring speed of the large-particle reaction, the pH value and the ammonia water concentration in the bottom solution and the reaction process were changed.

[0218] For all the above examples and comparative example samples, lithium hydroxide and the high-nickel doped precursor were solid-phase mixed evenly in a high-speed mixer at a molar ratio of 1.07:1, and the high-nickel doped cathode material was obtained by sintering at 665 °C and 680 °C for 5 h respectively. The electrochemical performance of the high-nickel doped cathode material was tested using a button-type half-cell: the above cathode material, conductive carbon black, and binder PVDF (polyvinylidene fluoride) were mixed into a slurry in a ratio of 8:1:1, coated on aluminum foil to make a positive electrode sheet, the negative electrode sheet was made of a lithium metal sheet, and the electrolyte was 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1). In a vacuum glove box, the battery case, positive and negative electrode sheets, separator, shrapnel, and gasket were assembled into a button battery. The electrochemical performance was tested using a Blue Power test system, and the C / 20 discharge specific capacity, first Coulomb efficiency, and 50-week cycle retention rate were tested under the conditions of 3.0 - 4.3 V and 25 °C. Figure 15 、 Figure 16 、 Figure 17 and Figure 18 are the schematic diagrams of the cycle performance of the button batteries prepared from the materials obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 respectively.

[0219] The test performance is as shown in Tables 1 and 2 below.

[0220] Table 1 Comparison of XRD diffraction data of precursors

[0221]

[0222] According to the data in Table 1, for the high-nickel cobalt-free doped precursor of the present invention, the primary particles on its surface are scaly and are inclined and stacked on the surface of the secondary particles along a non-radial direction. Through X-ray diffraction (XRD) analysis, the full width at half maximum α of the (001) crystal plane corresponding to the diffraction angle 2θ = 19.2 ± 1° is 0.254° to 0.270°, and the full width at half maximum β of the (101) crystal plane corresponding to the diffraction angle 2θ = 38.5 ± 1° is 0.316° to 0.326°; in Examples 1 and 2, the peak intensity I 001 of the (001) crystal plane corresponding to the diffraction angle 2θ = 38.5 ± 1° and the peak intensity I 101 of the (101) crystal plane corresponding to the diffraction angle 2θ = 19.2 ± 1° are both higher than those in Comparative Example 1, and I 101 / I 001 is 0.54 to 0.75, indicating that the structure of the present invention preferentially grows on the (001) crystal plane and has a narrower full width at half maximum compared to Comparative Example 1, and the crystallinity of the (001) plane in Examples 1 and 2 is better.

[0223] Table 2 Performance Parameters and Data

[0224]

[0225] According to the data in Table 2, the 50-week cycle rate of the coin-type half-cell prepared from the cathode material obtained by sintering the samples of Examples 1-4 at 665 °C for 5 h is 92.30% to 95.00%, and the 50-week cycle rate of Comparative Examples 1 and 2 is 82.74% to 89.13%. That is, when the primary particles on the surface of the precursor are scaly and are inclined and stacked on the surface of the secondary particles along a non-radial direction, the 50-week cycle rate of the coin-type half-cell prepared from the cathode material obtained by sintering is 3.17% to 12.26% higher than that of the coin-type battery prepared from the precursor material with radially distributed primary particles on the surface, and the difference is significant.

[0226] The 50-week cycle rate of the coin-type half-cell prepared from the cathode material obtained by sintering the samples of Examples 1-4 at 680 °C for 5 h is 91.36% to 93.87%, and the 50-week cycle rate of Comparative Examples 1 and 2 is 68.07% to 80.94%. That is, when the primary particles on the surface of the precursor are scaly and are inclined and stacked on the surface of the secondary particles along a non-radial direction, the 50-week cycle rate of the coin-type half-cell prepared from the cathode material obtained by sintering is 10.42% to 25.80% higher than that of the coin-type battery prepared from the precursor material with radially distributed primary particles on the surface, and the difference is significant.

[0227] Moreover, when the average angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor becomes smaller, the 50-week cycle performance value tends to be higher.

[0228] Comparative Examples 1 to 2 use a traditional continuous method to prepare a high nickel-doped aluminum precursor without using a seed crystal method. The surface primary particles in the obtained product are radially distributed without special morphology, and there are no obvious pores inside the CP diagram. In Examples 1 to 4, the structure prepared by the seed crystal method with de-micronization is that the surface primary particles are scaly, and then stacked on the surface of the secondary particles at a certain inclination angle in the non-radial direction, and the precursor has some relatively uniformly distributed small circular holes inside. The high nickel-doped positive electrode active material synthesized based on the special structure of the high nickel-doped precursor with inclined stacking growth of the surface primary particles of the present invention has a wide particle size distribution and a high tap density, and has a good first discharge specific capacity; at the same time, it can also avoid the problem of expansion and contraction of the radially arranged primary particles during sintering to produce cracks due to the radial distribution of the surface primary particles, and has a good cycle capacity retention rate. However, Comparative Examples 1 and 2 cannot take into account both the first charge and discharge electric specific capacity and the cycle capacity retention rate at the same time.

[0229] The non-radial structured high-nickel precursor provided in the embodiment of the present application starts from the microscopic morphology of the material and controls the reaction and doping conditions to make the precipitated particles grow preferentially on the 001 crystal plane. The primary particles on the surface are scaly and stacked obliquely on the surface of the secondary particles along the non-radial direction, avoiding the formation of vertically embedded radial structures such as points and needles, and appropriately increasing the uniform internal pores, which is beneficial to improving the internal stress of the material particles, avoiding the rapid deintercalation of lithium ions to destroy the crystal structure, improving the radial cracking problem of the particles, and improving the cyclic stability of the material.

[0230] The preparation method provided in the embodiment of the present application is a high nickel continuous output process with non-radial structure of primary particles on the surface. The preparation method uses seed crystals to avoid primary nucleation and can be produced continuously. The generated secondary particles have a wide particle size distribution. The primary particles on the surface have a special scaly morphology and are stacked obliquely on the surface of the secondary particles along the non-radial direction. It can effectively improve the high nickel structure under the conventional continuous process. The structure is dense and non-porous and the secondary particles have more primary nucleation on the surface of the micropowder. At the same time, it has certain pores that are conducive to full contact with the battery electrolyte. The battery material prepared by this product has a higher capacity and effectively improves the service life and cycle stability of the material.

[0231] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0232] In addition, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, the combination of features of different embodiments is meant to be within the scope of this application and forms different embodiments. For example, in the claims above, any one of the claimed embodiments can be used in any combination. The information disclosed in this background section is only for the purpose of enhancing the understanding of the overall background of this application and should not be regarded as an admission or any form of suggestion that this information constitutes prior art known to those skilled in the art.

Claims

1. A precursor with non-radial growth of surface primary particles, characterized in that, The primary particles on the surface of the precursor are flaky and are stacked on the surface of the secondary particles in an inclined manner along a non-radial direction; The precursor has a half-peak width α of the (001) crystal plane corresponding to a diffraction angle 2θ = 19.2 ± 1° and a half-peak width β of the (101) crystal plane corresponding to a diffraction angle 2θ = 38.5 ± 1°, and each of α and β is independently 0.2 - 0.4, and β / α ≥ 1.0; the precursor has a peak intensity I 001 of the (001) crystal plane corresponding to a diffraction angle 2θ = 19.2 ± 1° and a peak intensity I 101 of the (101) crystal plane corresponding to a diffraction angle 2θ = 38.5 ± 1°, and I 101 / I 001 is 0.5 - 0.

8.

2. The precursor for non-radial growth of surface primary particles according to claim 1, wherein The precursor satisfies at least one of the following conditions: A. The interior of the precursor has pores; B. The average particle size D50 of the precursor is 10 - 20 μm; C. The particle size distribution (D90 - D10) / D50 of the precursor is 1.25 - 1.65; D. The BET of the precursor is 10 - 20 m 2 / g; E. The TD of the precursor is 2.0 - 2.5 g / cm 3 ; F. The secondary particles of the precursor are spherical or quasi-spherical, and the average included angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0° - 60°; G. The average aspect ratio of the primary particles on the surface of the precursor is 1.0 - 2.0; H. The chemical general formula of the precursor is Ni a M 1-a (OH)2, 0.6 ≤ a < 1, and M is at least one of Co, Mn, Al, Ti, Zr, Mo, Cr, W, B, Mg, Ba, Nb or Sr.

3. The precursor of non-radial growth of surface primary particles according to claim 1, characterized in that, The precursor satisfies at least one of the following conditions: A. The interior of the precursor has pores, and the porosity of the precursor is 2.5% - 6.5%; B. The average particle size D50 of the precursor is 10 - 15 μm; C. The secondary particles of the precursor are spherical or quasi-spherical, and the average included angle γ between the primary particles on the surface of the precursor and the tangent plane of the sphere of the secondary particles of the precursor is 0° - 45°.

4. The precursor with non-radial growth of surface primary particles according to any one of claims 1-3, characterized in that The precursor satisfies at least one of the following conditions: I. The half-peak width α of the (001) crystal plane is 0.254 - 0.270, and the half-peak width β of the (101) crystal plane is 0.316 - 0.326; K. The chemical general formula of the precursor is Ni a Al b X c (OH)2, where X is Mn and / or Zr, a + b + c = 1, 0.6 ≤ a < 1, 0 ≤ b < 0.3, 0 ≤ c < 0.

1.

5. The precursor with non-radial growth of surface primary particles according to any one of claims 1-3, characterized in that, The chemical general formula of the precursor is Ni a Al b X c (OH)2, where X is Mn and / or Zr, a + b + c = 1, 0.9 ≤ a < 1, 0 ≤ b < 0.05, 0 ≤ c < 0.

05.

6. A method for preparing a precursor with non-radial growth of surface primary particles according to any one of claims 1-5, characterized in that, Including: Under the protection of an inert gas, raw materials including a metal salt solution, a doped metal salt solution, a precipitant, and a complexing agent are introduced into a first bottom liquid to carry out a first reaction to obtain a seed slurry; Under the protection of an inert gas, the seed slurry, the metal salt solution, the doped metal salt solution, the precipitant, and the complexing agent are introduced into a second bottom liquid to carry out a second reaction to obtain the precursor with non-radial growth of the primary particles on the surface; the hourly addition amount of the seeds is 0.05 wt% - 0.15 wt% of the hourly output; During the processes of carrying out the first reaction and the second reaction, the reaction pH is independently controlled to be 10.5 - 12.5; the ammonia concentration during the first reaction process is controlled to be 1 - 17 g / L, and the ammonia concentration during the second reaction process is controlled to be 10 - 17 g / L; during the processes of carrying out the first reaction and the second reaction, the stirring speed of the reaction is independently controlled to be 200 - 1200 r / min.

7. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The D50 of the seeds obtained from the first reaction is 2 - 8 μm.

8. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, During the processes of carrying out the first reaction and the second reaction, the reaction temperature is independently controlled to be 35 - 75 °C for each.

9. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The first bottom liquid and the second bottom liquid each independently include water, a precipitant, and a complexing agent.

10. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 9, characterized in that, The precipitant includes one or more of a sodium hydroxide solution, a potassium hydroxide solution, and a lithium hydroxide solution, and the complexing agent includes one or more of ammonia water, an ammonium bicarbonate solution, and an ammonium carbonate solution.

11. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 9, wherein, The pH of the first bottom liquid is 11.5 - 12.5, and the ammonia concentration is 0.24 - 0.85 mol / L; the pH of the second bottom liquid is 10.7 - 11.7, and the ammonia concentration is 0.6 - 0.9 mol / L.

12. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 9, wherein, The concentrations of the precipitating agent and the complexing agent are each independently 2 - 20 mol / L.

13. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The metal salts in the metal salt solution include one or more of nickel salts, aluminum salts, manganese salts, and cobalt salts.

14. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The doping metal salts in the doping metal salt solution include one or more of cobalt salts, titanium salts, zirconium salts, molybdenum salts, chromium salts, tungsten salts, boron salts, magnesium salts, barium salts, niobium salts, and strontium salts.

15. The method for preparing a precursor with non-radial growth of surface primary particles according to claim 13, wherein, The nickel salts include one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel chloride, and the aluminum salts include one or more of aluminum sulfate, aluminum nitrate, aluminum acetate, and aluminum chloride; The manganese salts include one or more of manganese sulfate, manganese chloride, and manganese nitrate; the cobalt salts include one or more of cobalt sulfate, cobalt chloride, and cobalt nitrate.

16. The method for preparing a precursor with non-radial growth of surface primary particles according to claim 14, wherein The zirconium salts include zirconium sulfate and / or zirconium nitrate.

17. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The doping metal salt solution further includes a buffer, and the buffer includes sodium citrate.

18. The preparation method of the precursor with non-radial growth of surface primary particles according to claim 6, characterized in that, The total concentration of metal ions in the metal salt solution is 1 - 5 mol / L.

19. The preparation method of the precursor with non-radial growth of surface primary particles according to any one of claims 6-18, characterized in that, After the second reaction, it further includes: after solid-liquid separation, a filter cake and a filtrate are obtained. The filter cake is the wet material of the precursor. The wet material of the precursor is subjected to alkali washing, water washing, drying, screening, and demagnetization to obtain the precursor, and the drying temperature is 60 - 200 °C.

20. A cathode material for a lithium-ion battery, characterized in that, Its raw materials include the precursor with non-radial growth of surface primary particles according to any one of claims 1 - 5.

21. The cathode material for a lithium-ion battery according to claim 20, wherein The positive electrode material of the lithium-ion battery has a peak intensity I of the (003) crystal plane corresponding to a diffraction angle 2θ = 18.5 ± 1° 003 and a peak intensity I of the (104) crystal plane corresponding to a diffraction angle 2θ = 44.0 ± 1° 104 , I 003 / I 104 > 1.

2.

22. A lithium-ion battery, characterized in that, Its raw materials include the lithium ion battery cathode material according to claim 20 or 21.

23. An electricity-related device, characterized in that, It includes the lithium ion battery according to claim 22.

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