Cathode material precursor, preparation method thereof, lithium ion battery cathode material, lithium ion battery and electrical equipment

Abstract

This invention relates to the field of lithium-ion battery technology, and discloses a cathode material precursor and its preparation method, a lithium-ion battery cathode material, a lithium-ion battery, and electrical equipment. The cathode material precursor is a nickel-containing hydroxide; the grain size D of the cathode material precursor on the (001) crystal plane is... (001) The grain size D of the cathode material precursor on the (100) crystal plane is... (100) And the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The value ranges from 6.1 to 9.8. The positive electrode material prepared by sintering the positive electrode material precursor provided by the present invention into a positive electrode material has excellent capacity performance and rate performance when used to prepare a lithium-ion battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to doped cathode material precursors and their preparation methods, lithium-ion battery cathode materials, lithium-ion batteries, and electrical equipment. Background Technology

[0002] With the rapid development of electric vehicles, consumer demand for them is increasing daily. The power batteries in electric vehicles are primarily lithium-ion batteries. The driving range of an electric vehicle is closely related to the capacity performance of the lithium-ion battery, the charging speed is closely related to the battery's performance, and the lifespan is closely related to its cycle performance. Currently, consumers' main anxieties about electric vehicles lie in how to improve their driving range and charging speed while ensuring a longer lifespan. This places higher demands on the capacity and rate performance of lithium-ion batteries in electric vehicles under high cycle performance conditions.

[0003] The cathode material is obtained by sintering the cathode material precursor with a lithium source. The properties of the cathode material are greatly affected by the cathode material precursor. Therefore, there is an urgent need to develop a ternary cathode material and its corresponding cathode material precursor that have high discharge capacity and excellent rate performance under high cycle performance, in order to improve the capacity and rate performance of lithium-ion batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a cathode material precursor and its preparation method, a lithium-ion battery cathode material, a lithium-ion battery, and electrical equipment, aiming to solve or at least alleviate the defects existing in the prior art.

[0005] To achieve the above objectives, a first aspect of the present invention provides a cathode material precursor, wherein the cathode material precursor is a nickel-containing hydroxide;

[0006] The positive electrode material precursor has a grain size D on the (001) crystal plane. (001) for The precursor of the cathode material has a grain size D on the (100) crystal plane. (100) and the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-9.8;

[0007] Wherein, the (001) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 18.0° to 20.0°; the (100) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 32.0° to 34.0°.

[0008] Optionally, the (101) crystal plane of the cathode material precursor corresponds to a diffraction peak at a diffraction angle 2θ of 37.5° to 39.5°, and the cathode material precursor satisfies at least one of the following conditions:

[0009] A. The precursor has a grain size D on the (101) crystal plane. (101) for Optionally, D (101) for

[0010] B. The grain size D of the cathode material precursor on the (100) crystal plane (100) and the grain size D on the (101) crystal plane (101) The ratio D (100) / D (101) The value is 3.0-6.5; optionally, D (100) / D (101) The value is 3.2-6.3.

[0011] Optionally, the (101) crystal plane of the cathode material precursor corresponds to a diffraction peak at a diffraction angle 2θ of 37.5° to 39.5°, and the cathode material precursor satisfies at least one of the following conditions:

[0012] A. The grain size D of the cathode material precursor on the (001) crystal plane. (001) for

[0013] B. The grain size D of the cathode material precursor on the (100) crystal plane (100) for Optionally, D (100) for

[0014] C. The grain size D of the cathode material precursor on the (100) crystal plane. (100) and the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-8.8;

[0015] D. The grain size D of the cathode material precursor on the (101) crystal plane. (101) and the grain size D on the (001) crystal plane (001) The ratio D (101) / D (001) The value is 1.2-2.0; optionally, D (101) / D (001) It is 1.2-1.7;

[0016] E. The peak intensity ratio I of the cathode material precursor on the (101) crystal plane and on the (001) crystal plane. (101) / I (001) It is 1.1-1.5; optionally, I (101) / I (001) It is 1.1-1.4.

[0017] According to one optional specific embodiment, the precursor satisfies at least one of the following conditions:

[0018] A. The average particle size D50 of the cathode material precursor is 2μm-18μm;

[0019] B. The particle size distribution of the cathode material precursor is Span = (D90 - D10) / D50 = 1.2 - 1.6;

[0020] C. The specific surface area (BET) of the cathode material precursor is 20m². 2 / g-40m 2 / g;

[0021] D. The tap density TD of the cathode material precursor is 1.2 g / m³. 3 -2.0m 2 / g;

[0022] E. The molar ratio of nickel content to total metal content in the cathode material precursor is ≥50 mol%.

[0023] F. The chemical formula of the cathode material precursor is Ni. a Co b Mn c M d (OH) e (XO4) f Wherein, 0.6≤a<1, 0≤b≤0.3, 0≤c≤0.2, 0≤d≤0.2, 1.7≤e≤2.3, 0≤f<0.2, a+b+c+d=1, M is at least one of Mg, Nb, Zr, Y, Al, Zn, Ti, Sr; X is Mo and / or W.

[0024] A second aspect of the present invention provides a method for preparing the cathode material precursor described in the first aspect above. The method includes: adding a nickel-containing metal salt solution, a precipitant solution, and a complexing agent solution in parallel to a reaction vessel containing a bottom liquid under an inert atmosphere to carry out a co-precipitation reaction; controlling the pH value of the co-precipitation reaction to first decrease and then maintain it within a certain range until the material in the reaction vessel grows to the target particle size; collecting the overflow solution and performing post-processing to obtain the cathode material precursor.

[0025] The base liquid is a mixture of water, the precipitant solution, and the complexing agent solution; the oxygen content of the inert atmosphere in the reactor is controlled to be <0.5v.

[0026] Optionally, the method satisfies at least one of the following conditions:

[0027] a. The pH value of the base solution is 11.4-12.0;

[0028] b. The ammonia concentration in the substrate solution is 3g / L-9g / L;

[0029] c. A solution containing a dopant element M is also introduced concurrently into the bottom liquid, wherein the dopant element M is at least one of Al, Ti, Zr, Mo, Cr, W, Mg, Ba, Nb or Sr;

[0030] d. A solution containing dopant element M is also introduced concurrently into the bottom liquid, wherein the mass concentration of dopant element M in the solution containing dopant element M is independently 2 g / L-11 g / L.

[0031] e. A solution containing anion X is also introduced concurrently into the bottom liquid, wherein the anion X is Mo. 6+ and / or W 6+ ;

[0032] f. A solution containing anion X is also introduced concurrently into the base liquid, wherein the mass concentration of anion X in the solution containing anion X is 3 g / L-18 g / L.

[0033] g. Control the flow rate of the nickel-containing metal salt solution during the co-precipitation reaction to be 4%-10% of the reactor volume per hour.

[0034] h. Controlling the flow rate ratio of the nickel-containing metal salt solution to the precipitant solution in the co-precipitation reaction to be (2.4-3.0):1;

[0035] i. Control the flow rate ratio of the precipitant solution to the complexing agent solution in the coprecipitation reaction to be (10-23):1;

[0036] j. Control the pH value of the coprecipitation reaction to decrease from 11.4-12.0 to 10.6-11.5;

[0037] k. Control the pH value of the coprecipitation reaction to decrease over a period of 2-5 hours;

[0038] l. Control the ammonia concentration in the co-precipitation reaction to be 2 g / L-10 g / L.

[0039] Optionally, the method satisfies at least one of the following conditions:

[0040] a. The precipitant solution includes sodium hydroxide;

[0041] b. The mass fraction of the precipitant in the precipitant solution is 20wt%-40wt%;

[0042] c. The complexing agent solution includes ammonia water;

[0043] d. The mass fraction of the complexing agent in the complexing agent solution is 10wt%-30wt%;

[0044] e. The nickel-containing metal salt solution also includes cobalt ions and / or manganese ions;

[0045] f. The sum of the molar concentrations of each metal ion in the nickel-containing metal salt solution is 1 mol / L to 3 mol / L;

[0046] g. Control the temperature of the coprecipitation reaction to be 55℃-65℃;

[0047] h. Control the stirring speed of the precipitation reaction to be 500 rpm-1000 rpm.

[0048] A third aspect of the present invention provides a lithium-ion battery cathode material, wherein the raw materials for the lithium-ion battery cathode material include the cathode material precursor described in the first aspect above.

[0049] A fourth aspect of the present invention provides a lithium-ion battery comprising the lithium-ion battery cathode material as described in the third aspect above.

[0050] A fifth aspect of the present invention provides an electrical device comprising a lithium-ion battery as described in the fourth aspect above.

[0051] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0052] The grain size of the cathode material precursor has a significant impact on the capacity of lithium-ion batteries. The (001) crystal plane of the cathode material precursor corresponds to the (003) crystal plane of the cathode material. The (003) crystal plane of the cathode material is thermodynamically stable and electrochemically inert, which is unfavorable for Li-ion batteries. + The transmission requires controlling the exposure of the (001) crystal plane of the cathode material precursor, that is, limiting the size of the grain size of the (001) crystal plane.

[0053] The (100) crystal plane of the cathode material precursor acts as Li + The larger the grain size of the (100) crystal plane, the larger the exposed surface, which is more beneficial to Li. + The insertion / deintercalation of the cathode material precursor improves the capacity and rate performance of the cathode material after it is sintered into a lithium-ion battery.

[0054] But D (100) / D (001) If the ratio is too large, the grain size difference between different crystal planes will be too great, which may affect the structural stability of the grains, making them brittle and greatly affecting cycle performance; D (100) / D (001) If the ratio is too small, the effect of improving the capacity and rate performance of the sintered cathode material after it is made into a lithium-ion battery will be not obvious or poor.

[0055] The positive electrode material precursor provided by this invention has a grain size D on the (001) crystal plane. (001) The smaller size of the cathode material after sintering is unfavorable for Li. + The grain size of the migrating inert (003) crystal plane is also smaller; and its D (100) / D (001) A relatively large ratio of [specific value] is beneficial for Li-ion batteries to achieve higher cycle performance after sintering into a positive electrode material. + The insertion / deintercalation of the (100) crystal plane exhibits high capacity and rate performance.

[0056] The preparation method provided by the present invention controls the preferential growth of the (100) crystal plane by adjusting the reaction parameters, and suppresses the growth of the (001) crystal plane and the (101) crystal plane, so as to obtain a product with specific crystal grain size of each crystal plane that meets the above requirements. Attached Figure Description

[0057] Figure 1 This is the XRD pattern of the cathode material precursor obtained in Example 1 of the present invention;

[0058] Figure 2 This is the XRD pattern of the cathode material precursor obtained in Example 2 of this invention;

[0059] Figure 3 This is the XRD pattern of the cathode material precursor prepared in Comparative Example 1 of this invention;

[0060] Figure 4 This is the XRD pattern of the cathode material precursor prepared in Comparative Example 2 of this invention;

[0061] Figure 5 This is the XRD pattern of the cathode material precursor prepared in Comparative Example 3 of this invention. Detailed Implementation

[0062] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0063] It should be noted that, in all aspects of the present invention, the same components or terms in each aspect are described only once in one aspect and not repeatedly, and those skilled in the art should not understand this as a limitation of the present invention.

[0064] It should be noted that the "half-peak width" of the diffraction peak corresponding to a certain crystal plane in the XRD pattern described in this invention and the "grain size" calculated from the data in the XRD pattern are both well-known in the art.

[0065] As mentioned above, a first aspect of the present invention provides a cathode material precursor, wherein the cathode material precursor is a nickel-containing hydroxide;

[0066] The grain size D of the (001) crystal plane of the cathode material precursor (001) for For example, D (001) It can be or Any value between;

[0067] The precursor of the cathode material has a grain size D on the (100) crystal plane. (100) and the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-9.8; for example, D. (100) / D (001) It can be any value between 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8 or 6.1-8.8, 8.8-9.8, 6.1-8.0, 6.1-7.2, 7.2-8.8;

[0068] Wherein, the (001) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 18.0° to 20.0°; the (100) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 32.0° to 34.0°.

[0069] Optionally, the grain size D of the cathode material precursor on the (001) crystal plane is... (001) for

[0070] Optionally, the grain size D of the cathode material precursor on the (100) crystal plane is... (100) And the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-8.8.

[0071] It should be noted that the full width at half maximum (FWHM(001)) of the diffraction peak corresponding to the (001) crystal plane in the XRD pattern of the cathode material precursor represents the width of the diffraction peak corresponding to the (001) crystal plane when the peak height is half, in degrees (°). The grain size D of the (001) crystal plane... (001) The grain size is obtained by fitting the diffraction peak values ​​corresponding to the (001) crystal plane, and the unit is angstrom. The value can be calculated using the Scherrer formula D = Kλ / (βcosθ), where K is the Scherrer constant, λ is the X-ray wavelength, β is the half-width of the diffraction peak corresponding to the (001) crystal plane, and θ is the diffraction angle of the (001) crystal plane.

[0072] For example, the grain size data of the cathode material precursor in Embodiment 1 of the present invention can be obtained by refining the XRD data obtained from the test using the Rigaku XRD analysis software package and then calculating it using the Scherrer formula; alternatively, it can be calculated directly from the XRD test data using the Scherrer formula. In the above Scherrer formula, K = 0.89 is selected, and the X-ray wavelength λ is... The diffraction angle 2θ is 19.982°, and the half-peak width β of the diffraction peak corresponding to the (001) crystal plane is 2.083° (converted to radians as [(β÷180)×π]). The calculation process is as follows:

[0073]

[0074] It should be understood that, as D (100) / D (001) >9.8, excessively large differences in grain size across crystal planes may affect the structural stability of the grains, making them brittle and impacting cycle performance; such as D (100) / D (001)<6.1, the effect of sintered cathode material on improving capacity and rate performance in lithium-ion batteries is not significant or is poor. In this invention, the grain size D of the cathode material precursor on the (001) crystal plane is controlled. (001) for And the grain size D of the cathode material precursor on the (100) crystal plane (100) And the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) With a strength of 6.1-9.8, the obtained cathode material precursor, after being sintered into cathode material and prepared into lithium-ion battery cathode material, exhibits excellent capacity and rate performance under high cycle performance.

[0075] In this embodiment of the invention, the (101) crystal plane of the cathode material precursor corresponds to a diffraction peak at a diffraction angle 2θ of 37.5° to 39.5°.

[0076] In some embodiments, the positive electrode material precursor has a grain size D on the (100) crystal plane. (100) for For example, it can be... or Any value between;

[0077] Optionally, the grain size D of the cathode material precursor on the (100) crystal plane is... (100) for

[0078] Such as D (100) If the grain size is too large, the difference in grain size between different crystal planes will be too great, which may affect the structural stability of the grains, making them brittle and affecting cycle performance. The grain size D of the (100) crystal plane of the cathode material precursor of the present invention is... (100) The larger size of the cathode material after sintering, when used to prepare the battery, is beneficial for Li in terms of higher cycle performance. + Embedding / de-embedding improves capacity and rate performance.

[0079] In some embodiments, the grain size D of the cathode material precursor on the (101) crystal plane is... (101) for For example, it can be... Or for Any value between;

[0080] Optionally, the grain size D of the cathode material precursor on the (101) crystal plane is... (101) for

[0081] The cathode material precursor (101) has a Li crystal plane. + The perpendicular crystal plane of the insertion / deintercalation channel, the (101) crystal plane has a small grain size, which can shorten the Li + The migration distance, thereby improving Li + The mobility. (101) Grain size D of the crystal plane. (101) Within this range, it is beneficial to improve the capacity and rate performance of lithium-ion batteries.

[0082] In some embodiments, the positive electrode material precursor has a grain size D on the (100) crystal plane. (100) and the grain size D on the (101) crystal plane (101) The ratio D (100) / D (101) The range is 3.0-6.5, for example, it can be any value between 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5 or 3.0-4.0, 4.0-5.0, 5.0-6.5, or 3.0-6.5;

[0083] Optionally, the grain size D of the cathode material precursor on the (100) crystal plane is... (100) and the grain size D on the (101) crystal plane (101) The ratio D (100) / D (101) The value is 3.2-6.3;

[0084] Such as D (100) / D (101) If the ratio is too large, the difference in grain size between different crystal planes will be too great, which may affect the structural stability of the grains; such as D (100) / D (101) If the ratio is too small, the improvement in battery capacity and rate performance will not be significant. (100) Grain size D of the crystal plane (100) And the grain size D on the (101) crystal plane (101) The ratio D (100) / D (101) Within this range, at higher cycling performance, it is beneficial for Li + Embedding / de-embedding, and shortening Li + This increases the transmission distance, thereby improving the capacity and rate performance of lithium-ion batteries.

[0085] In some embodiments, the grain size D of the cathode material precursor on the (101) crystal plane is... (101) and the grain size D on the (001) crystal plane (001) The ratio D (101) / D (001) It can be 1.2-2.0, for example, it can be any value between 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or 1.2-2.0, 1.2-1.4, or 1.4-2.0;

[0086] Optionally, the grain size D of the cathode material precursor on the (101) crystal plane is... (101) and the grain size D on the (001) crystal plane (001) The ratio D (101) / D (001) It is 1.2-1.7;

[0087] The cathode material precursor provided by this invention has relatively small grain sizes on both the (001) and (101) crystal planes, while controlling D (101) / D (001) Within a suitable range, increase Li + The mobility of the (101) crystal plane is increased, thereby improving the rate performance.

[0088] In some embodiments, the peak intensity ratio I of the cathode material precursor on the (101) crystal plane and on the (001) crystal plane is... (101) / I (001) =1.1-1.5, for example, it can be any value between 1.1, 1.2, 1.3, 1.4, 1.5 or 1.1-1.1, 1.2-1.3, 1.3-1.4, 1.4-1.5, and 1.1-1.5;

[0089] Optionally, the peak intensity ratio I of the cathode material precursor on the (101) crystal plane and on the (001) crystal plane is... (101) / I (001) It is 1.1-1.4;

[0090] The cathode material precursor provided by this invention has relatively small grain sizes on both the (001) and (101) crystal planes, while controlling the peak intensity ratio I of the cathode material precursor. (101) / I (001) The value is 1.06-1.30. That is, during the preparation process, the cathode material precursor is controlled in the Li... + The growth advantage of the vertical crystal plane of the insertion / deintercalation channel—the (101) crystal plane—is greater than that of the (003) and (001) crystal planes in the cathode material. Reducing the exposure of the (001) crystal plane can improve the Li +The mobility on the (101) crystal plane improves rate performance. For example, I... (101) / I (001) If the ratio is too large, it may affect the structural stability of grains with various crystal planes.

[0091] In some embodiments, the cathode material precursor is a nickel-containing hydroxide, wherein the molar ratio of nickel content to total metal content in the nickel-containing hydroxide is ≥50 mol%, for example, it can be any value among ≥60 mol%, ≥65 mol%, ≥70 mol%, ≥75 mol%, ≥80 mol%, ≥85 mol%, ≥90 mol%, ≥95 mol%, or 50 mol%-99 mol%.

[0092] In some embodiments, the chemical formula of the cathode material precursor is Ni. a Co b Mn c M d (OH) e (XO4) f Wherein, 0.6≤a<1, 0≤b≤0.3, 0≤c≤0.2, 0≤d≤0.2, 1.7≤e≤2.45, 0≤f≤0.2, a+b+c+d=1, M is at least one of Mg, Nb, Zr, Y, Al, Zn, Ti, and Sr, and X is Mo and / or W; optionally, 1.9≤e≤2.3, and M is at least two of Mg, Nb, Zr, Y, Al, Zn, Ti, and Sr.

[0093] Optionally, in the chemical formula of the cathode material precursor, a can be any value between 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.96, 0.99 or 0.6≤a<0.7, 0.7≤a≤0.8, 0.5≤a≤0.7, 0.70≤a<1; e can be any value between 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 or 1.7≤e≤2.5; and f can be any value between 0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.14, 0.16, 0.18, 0.20 or 0≤f≤0.05, 0≤t≤0.1, 0.1≤t≤0.2.

[0094] In some embodiments of the present invention, the cathode material precursor is doped with multiple elements, which can affect the lattice arrangement of atoms within the grains, effectively suppressing the volume change rate of the lithium-ion cathode material during charge and discharge, preventing the lithium-ion cathode material from failing to contact the electrolyte due to volume expansion and contraction, thereby improving the electrochemical performance of the lithium-ion battery. Among these, Al... 3+It can improve cycle performance; Zr 4+ It can form a stable solid layer; Zr 4+ A large ionic radius increases the c-axis distance of the unit cell, which is beneficial for ion migration; Sr 2+ Al 3+ The incorporation of Mg increases conductivity, facilitates ion migration, and is beneficial for improving rate performance; 2+ Ti 4+ Y 3+ The incorporation of Ni can balance the effects of Ni 2+ The resulting inversion defects, and can suppress Ni 2+ Further migration into the lithium layer enhances the integrity and stability of the material's crystal structure, which is beneficial for improving capacity and rate performance; through Zr 4+ Zn 2+ Modification can improve its crystal structure stability, inhibit electrolyte corrosion and oxygen evolution, and improve cycle performance; introducing high-valence metal ions, such as Nb 5+ Mo 6+ W 6+ This invention constructs a composite structure with rock salt or spinel phases and layered phases, reducing crystallinity, resulting in smaller grain size and improved rate performance. The invention employs multiple doping elements to maximize the advantages of doping without producing significant side effects.

[0095] In some embodiments, the average particle size D50 of the cathode material precursor is 2μm-18μm, for example, it can be any value between 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm or 2μm-18μm.

[0096] In some embodiments, the particle size distribution of the cathode material precursor is Span = (D90-D10) / D50 = 1.2-1.6, for example, it can be any value between 1.2, 1.3, 1.4, 1.5, 1.6 or 1.2-1.6.

[0097] A wider particle size distribution is beneficial to increasing the tap density of the cathode material precursor, thereby improving the battery's capacity performance.

[0098] In some embodiments, the specific surface area (BET) of the cathode material precursor is 20 m². 2 / g-40m 2 / g, for example, can be 20m 2 / g、21m 2 / g、22m 2 / g、23m 2 / g、24m2 / g、25m 2 / g、26m 2 / g、27m 2 / g、28m 2 / g、29m 2 / g、30m 2 / g、31m 2 / g、32m 2 / g、33m 2 / g、34m 2 / g、35m 2 / g、36m 2 / g、37m 2 / g、38m 2 / g、39m 2 / g、40m 2 / g or 20m 2 / g-40m 2 Any value between / g.

[0099] In some embodiments, the tap density TD of the cathode material precursor is 1.2 g / m³. 3 -2.0m 2 / g, for example, can be 1.2g / m 3 1.3g / m 3 1.4g / m 3 1.5g / m 3 1.6g / m 3 1.7g / m 3 1.8g / m 3 1.9g / m 3 2.0g / m 3 Or 1.2g / m 3 -2.0m 2 Any value between / g.

[0100] A second aspect of the present invention provides a method for preparing the cathode material precursor described in the first aspect above. The method includes: adding a nickel-containing metal salt solution, a precipitant solution, and a complexing agent solution in parallel to a reaction vessel containing a bottom liquid under an inert atmosphere to carry out a co-precipitation reaction; controlling the pH value of the co-precipitation reaction to first decrease and then maintain it within a certain range until the material in the reaction vessel grows to the target particle size; collecting the overflow solution and performing post-processing to obtain the cathode material precursor.

[0101] The base liquid is a mixture of water, the precipitant solution, and the complexing agent solution; the oxygen content of the inert atmosphere in the reactor is controlled to be <0.5v.

[0102] It should be noted that the present invention does not have any particular requirements for the selection of the inert gas, and those skilled in the art can select it as needed. For example, the inert gas can be N2.

[0103] The v% of the oxygen content in the inert atmosphere in the aforementioned reactor refers to the volume percentage of oxygen in the gas of the coprecipitation reactor relative to the total volume of the gas in the reactor.

[0104] It should be noted that the present invention does not have any particular requirements on the type of water, and those skilled in the art can select it as needed. For example, the water can be pure water or deionized water.

[0105] Ni 2+ and oxidized Ni 3+ The lattice arrangement within the grain affects the growth of each crystal facet; pH changes during the reaction can also affect the growth rate and arrangement of the grains. The preparation method provided by this invention, by controlling reaction parameters such as ultra-low oxygen content in the reactor and phased changes in pH value, inhibits the oxidation of low-valence metal ions to high-valence states, controls the preferential growth of the (100) crystal facet of the grain, and inhibits the growth of the (001) and (101) crystal faces, thereby obtaining a product with specific grain sizes for each crystal facet.

[0106] In some embodiments, the precipitant solution includes sodium hydroxide.

[0107] In some embodiments, the mass fraction of the precipitant in the precipitant solution is 20wt%-40wt%, for example, it can be any value between 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt%, 40wt%, or 20wt%-40wt%.

[0108] In some embodiments, the complexing agent solution includes ammonia.

[0109] In some embodiments, the complexing agent in the complexing agent solution has a mass fraction of 10wt%-30wt%, for example, it can be any value between 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, or 10wt%-30wt%.

[0110] In some embodiments, the nickel-containing metal salt solution further includes cobalt ions and / or manganese ions.

[0111] In some embodiments, the sum of the molar concentrations of the metal ions in the nickel-containing metal salt solution is 1 mol / L to 3 mol / L, for example, it can be any value between 1 mol / L, 2 mol / L, 3 mol / L or 1 mol / L to 3 mol / L.

[0112] In some embodiments, the pH of the substrate is 11.4-12.0, for example, it can be any value between 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0 or 11.4-12.0.

[0113] In some embodiments, the ammonia concentration in the base solution is 3 g / L-9 g / L, for example, it 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 or 3 g / L-9 g / L.

[0114] It should be noted that, in this invention, the ammonia concentration refers to the concentration of NH3·H2O in the co-precipitation reaction system.

[0115] During the preparation process, the concentration of the complexing agent and the pH value in the substrate can affect the reaction rate of the subsequent initial reaction and the lattice arrangement inside the crystals.

[0116] In some embodiments, a solution containing a dopant element M is also introduced concurrently into the bottom liquid, wherein the dopant element M is at least one selected from Al, Ti, Zr, Mo, Cr, W, Mg, Ba, Nb, or Sr.

[0117] In some embodiments, a solution containing dopant element M is also introduced concurrently into the base liquid, wherein the mass concentration of dopant element M in the solution containing dopant element M is independently 2 g / L-11 g / L, for example, it can be any value between 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 or 2 g / L-11 g / L.

[0118] In some embodiments, a solution containing anion X, wherein the anion X is Mo, is also introduced concurrently into the base liquid. 6+ and / or W 6+ The mass concentration of anion X in the solution containing anion X is 3 g / L-18 g / L, for example, it 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, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L or 3 g / L-18 g / L.

[0119] In some embodiments, the flow rate of the nickel-containing metal salt solution introduced into the coprecipitation reaction is controlled to be 4% / h-10% / h of the reactor volume, for example, it can be any value between 4% / h, 5% / h, 6% / h, 7% / h, 8% / h, 9% / h, 10% / h or 4% / h-10% / h.

[0120] In some embodiments, the flow rate ratio of the nickel-containing metal salt solution to the precipitant solution in the co-precipitation reaction is controlled to be (2.4-3.0):1, for example, it can be any value between 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1 or (2.4-3.0):1;

[0121] By controlling the flow rate ratio of the nickel-containing metal salt solution to the precipitant solution in the co-precipitation reaction, the crystallization rate of the precursor can be well controlled, and a precursor with a suitable grain size can be effectively regulated.

[0122] In some embodiments, the flow rate ratio of the precipitant solution to the complexing agent solution in the coprecipitation reaction is controlled to be (10-23):1, for example, it can be any value between 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, 21:1, 23:1 or (10-23):1;

[0123] By controlling the flow rate ratio of the nickel-containing metal salt solution to the complexing agent solution in the co-precipitation reaction, the crystallization rate of the precursor can be well controlled, and a precursor with a suitable grain size can be effectively regulated.

[0124] In some embodiments, the pH value of the coprecipitation reaction is controlled to decrease from 11.4-12.0 to 10.6-11.5. For example, the pH value of the coprecipitation reaction is controlled to decrease from any value among 11.4-12.0 to any value among 10.6-11.5. Any value among 11.4-12.0 can be any value among 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, and 12.0, and any value among 10.6-11.5 can be any value among 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, and 11.5. For example, the pH value of the coprecipitation reaction can also be controlled to decrease from 11.6 to 11.4, from 11.9 to 11.3, from 11.5 to 10.7, etc.

[0125] In some embodiments, the pH value of the coprecipitation reaction is controlled to decrease over a period of 2-5 hours, for example, any value between 2 hours, 3 hours, 4 hours, 5 hours, or 2-5 hours.

[0126] By controlling the pH change and the time it takes for the pH to drop, it is possible to effectively regulate the appropriate crystallization rate and prepare precursors with suitable crystal sizes.

[0127] In some embodiments, the ammonia concentration in the coprecipitation reaction is controlled to be 2 g / L-10 g / L, for example, it can be any value between 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 or 2 g / L-10 g / L.

[0128] It is important to note that maintaining the same ammonia concentration in the substrate as in the coprecipitation reaction can ensure consistent lattice arrangement within the crystal grains.

[0129] It is important to note that by controlling the flow rates of the nickel-containing metal salt solution, precipitant solution, and complexing agent solution, the pH value during the coprecipitation reaction can be reduced, and the rate of pH decrease can be controlled and then maintained to ensure that the coprecipitation reaction proceeds stably, resulting in a cathode material precursor with a specific particle size distribution and internal lattice arrangement.

[0130] In some embodiments, the temperature of the coprecipitation reaction is controlled to be 55°C-65°C, for example, it can be any value between 55°C, 57°C, 60°C, 62°C, 65°C or 55°C-65°C.

[0131] Controlling the appropriate reaction temperature can control the reaction rate and prepare precursors with suitable morphology and grain size.

[0132] In some embodiments, the stirring speed of the precipitation reaction is controlled to be 500 rpm-1000 rpm, for example, it can be any value between 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm or 500 rpm-1000 rpm.

[0133] The stirring speed affects the aggregation rate and arrangement of particles. The faster the stirring speed, the lower the porosity of the corresponding area of ​​the prepared product; conversely, the slower the stirring speed, the higher the porosity of the corresponding area of ​​the prepared product.

[0134] In the preparation method of the cathode material precursor of the present invention, the post-processing includes centrifugation, washing, demagnetization, packaging and other post-processing methods known in the art, so as to obtain the cathode material precursor with better quality. The present invention will not elaborate further here, and those skilled in the art should not understand it as a limitation of the present invention.

[0135] A third aspect of the present invention provides a lithium-ion battery cathode material, wherein the raw materials for the lithium-ion battery cathode material include the cathode material precursor described in the first aspect above.

[0136] This invention does not impose any particular limitations on the method for preparing lithium-ion battery cathode materials using the cathode material precursor provided by this invention; those skilled in the art can choose from known techniques. However, in order to obtain a lithium-ion battery cathode material with superior electrochemical performance, this invention may use the following methods to prepare the lithium-ion battery cathode material.

[0137] According to one optional specific embodiment, the method for preparing the lithium-ion battery cathode material includes:

[0138] The cathode material precursor and the lithium-containing compound are mixed evenly to obtain a mixture;

[0139] The mixture is sintered in an oxygen atmosphere to obtain the lithium-ion battery cathode material.

[0140] In some embodiments, the lithium-containing compound is lithium carbonate.

[0141] In some embodiments, the sintering conditions include: a temperature of 900°C-1100°C, for example, any value between 850°C, 900°C, 1000°C or 850°C-1000°C; and a time of 4h-6h, for example, any value between 4h, 5h, 6h or 4h-6h.

[0142] In some embodiments, the amounts of the cathode material precursor and the lithium-containing compound are controlled such that the molar ratio of Li to the total amount of other metal elements in the mixture is 1.03-1.05:1, for example, 1.03:1, 1.04:1, or 1.05:1.

[0143] It should be noted that the other metal elements mentioned in this invention refer to the metal elements in the mixture other than Li.

[0144] A fourth aspect of the present invention provides a lithium-ion battery comprising the lithium-ion battery cathode material as described in the third aspect above.

[0145] According to one optional specific embodiment, the lithium-ion battery is obtained by the following preparation method:

[0146] (1) Preparation of positive electrode sheet: The lithium-ion battery positive electrode material, conductive acetylene black and binder are mixed in a mass ratio of 8:1:1 to obtain a slurry. The slurry is evenly coated on the surface of aluminum foil using a scraper and a coating machine. The coated aluminum foil is then dried and pressed by a roller press 3-5 times before being cut into circles with a diameter of 14mm-16mm. The circles are then transferred to a vacuum oven in a glove box for drying to obtain the positive electrode sheet.

[0147] (2) Battery assembly: The positive electrode, negative electrode (lithium metal) and separator are wound into battery cores and then installed into the battery steel shell. Then, the battery is sequentially grooved, coated with sealing oil, welded with battery caps and filled with electrolyte to seal the opening. Finally, the battery is sorted and assembled.

[0148] In some embodiments, the adhesive is a polytetrafluoroethylene solution with a mass fraction of 6wt%-10wt%, for example, it can be any value between 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, or 6wt%-10wt%.

[0149] In some embodiments, the solvent in the polytetrafluoroethylene solution is N-methylpyrrolidone.

[0150] The present invention does not have special requirements for the mixing conditions; it is sufficient to mix the lithium-ion battery positive electrode material, the conductive acetylene black, and the binder evenly. For example, the mixing is performed in a mixing machine by running the machine forward at 2000-2400 rpm for 3-5 minutes, then reversed for 20-40 seconds as one cycle, for a total of 3-5 cycles to achieve uniform mixing.

[0151] In some embodiments, the drying conditions include a temperature of 60°C-100°C and a time of 2-4 hours.

[0152] The present invention does not have any particular requirements on the type of diaphragm, and those skilled in the art can select it as needed.

[0153] In some embodiments, the drying conditions include a temperature of 60°C-105°C and a time of 2-4 hours.

[0154] A fifth aspect of the present invention provides an electrical device comprising a lithium-ion battery as described in the fourth aspect above.

[0155] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials are all commercially available products.

[0156] Precipitating agent solution: sodium hydroxide solution, mass fraction 32.5 wt%.

[0157] Complexing agent solution: ammonia aqueous solution, mass fraction 20 wt%.

[0158] Example 1

[0159] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4)0.02 The specific preparation method of the cathode material precursor is as follows:

[0160] ①Raw material preparation:

[0161] Preparation of nickel-containing metal salt solution: Battery-grade nickel sulfate, battery-grade cobalt sulfate, battery-grade manganese sulfate and pure water are mixed and stirred to obtain nickel-containing metal salt solution. The molar ratio of Ni:Co:Mn in the nickel-containing metal salt solution is controlled to be 86.6:9.3:4.1, and the sum of the mass concentrations of nickel ions, cobalt ions and manganese ions is 2 mol / L.

[0162] Prepare a solution containing dopant element M: Weigh battery-grade magnesium sulfate to prepare a magnesium sulfate solution with a magnesium content of 2.03 g / L; weigh battery-grade niobium oxalate to prepare a niobium oxalate solution with a niobium content of 3.87 g / L; weigh battery-grade sodium molybdate to prepare a sodium molybdate solution with a molybdenum content of 7.99 g / L.

[0163] ② Coprecipitation reaction

[0164] Preparation of the base solution: In the reaction vessel, sodium hydroxide solution, ammonia solution and pure water are mixed to form the base solution. The pH of the base solution is controlled at 11.5 and the concentration of ammonia in the base solution is 4.5 g / L.

[0165] Under N2 protection (oxygen content <0.5v%), nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution and ammonia solution are fed concurrently into a reactor containing a bottom liquid for co-precipitation reaction;

[0166] The flow rate of the nickel-containing metal salt solution during the co-precipitation reaction was controlled at 7.5% / h of the reactor volume. The flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (47-49):(23.5-24.5):(23.5-24.5):(23.5-24.5):(17.8-18.2):1.

[0167] The temperature of the coprecipitation reaction was controlled at 60℃, the stirring speed at 900 rpm, and the pH value decreased from 11.50 to 11.3 over a period of 3 hours. Then, the pH value was kept constant, and the ammonia concentration was controlled at 4.3-4.7 g / L during the coprecipitation reaction until the material in the reactor grew to the target particle size. The overflow solution was collected and then washed, dried, sieved, demagnetized, and packaged to obtain the cathode material precursor.

[0168] Example 2

[0169] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0170] The pH of the base solution was controlled at 11.6, and the pH value during the coprecipitation reaction was controlled to decrease from 11.6 to 11.4. The flow rate ratio of the nickel metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (42-44):(21-22):(21-22):(21-22):(15.9-16.3):1. The ammonia concentration during the coprecipitation reaction was controlled at 4.8-5.2 g / L.

[0171] Other reaction parameters are the same as in Example 1, and so on.

[0172] Example 3

[0173] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0174] The coprecipitation reaction temperature was controlled at 65℃, the stirring speed at 800 rpm, and the flow rate of the nickel-containing metal salt solution at 6% / h of the reactor volume.

[0175] Example 4

[0176] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0177] The pH of the base solution was controlled at 11.9, and the ammonia concentration was 7 g / L. The pH value during the coprecipitation reaction was controlled so that the pH value decreased from 11.9 to 11.3 over a period of 4 hours. The flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (29.4-30.6):(14.7-15.3):(14.7-15.3):(14.7-15.3):(11.0-11.4):1. The ammonia concentration during the coprecipitation reaction was controlled at 7.0-7.4 g / L.

[0178] Example 5

[0179] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0180] The pH of the base solution was controlled at 12.0, and the pH value during the coprecipitation reaction was controlled to decrease from 12.0 to 11.3. The flow rate ratio of the nickel metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution and ammonia solution was (39-41):(19.5-20.5):(19.5-20.5):(19.5-20.5):(14.8-15.2):1. The ammonia concentration during the coprecipitation reaction was controlled at 5.3-5.7 g / L.

[0181] Example 6

[0182] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0183] The ammonia concentration of the base solution was controlled at 8 g / L. The flow rate ratio of the nickel metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution and ammonia solution was (25.8-26.3):(12.9-13.1):(12.9-13.1):(12.9-13.1):(9.6-9.9):1. The ammonia concentration during the coprecipitation reaction was controlled at 8.2-8.6 g / L.

[0184] Example 7

[0185] Prepare a chemical formula Ni 0.75 Co 0.12 Mn 0.09 Al 0.02 Zr 0.01 Nb 0.01 (OH) 2.05 (MoO4) 0.01 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0186] Preparation of nickel-containing metal salt solution: Battery-grade nickel sulfate, battery-grade cobalt sulfate, battery-grade manganese sulfate and pure water are mixed and stirred to obtain nickel-containing metal salt solution. The molar ratio of Ni:Co:Mn in the nickel-containing metal salt solution is controlled to be 78.1:12.5:9.4, and the sum of the molar concentrations of nickel ions, cobalt ions and manganese ions is 2 mol / L.

[0187] Weigh battery-grade aluminum sulfate to prepare an aluminum sulfate solution with an aluminum content of 2.16 g / L;

[0188] Weigh the battery-grade zirconium oxysulfate to prepare a zirconium oxysulfate solution with a zirconium content of 3.65 g / L;

[0189] Weigh battery-grade sodium molybdate to prepare a sodium molybdate solution with a molybdenum content of 4.00 g / L;

[0190] Preparation of the base solution: Control the pH of the base solution to 11.50 and the ammonia concentration to 5 g / L;

[0191] Under N2 protection (oxygen content <0.5v%), a nickel-containing metal salt solution, aluminum sulfate solution, zirconium oxysulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution are co-flowed into a reactor containing a bottom liquid for co-precipitation reaction. The flow rate of the nickel-containing metal salt solution during the co-precipitation reaction is controlled at 7.5% / h of the reactor volume, and the flow rate ratio of the nickel-containing metal salt solution, aluminum sulfate solution, zirconium oxysulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution is (43-45):(21.5-22.5):(21.5-22.5):(21.5-22.5):(16.2-16.6):1. The ammonia concentration during the co-precipitation reaction is controlled at 4.8-5.2 g / L.

[0192] Example 8

[0193] Prepare a chemical formula Ni 0.95 Mn 0.04 Y 0.01 (OH) 1.95 (MoO4) 0.03The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0194] Preparation of nickel-containing metal salt solution: Battery-grade nickel sulfate, battery-grade manganese sulfate and pure water are mixed and stirred to obtain nickel-containing metal salt solution. The molar ratio of Ni:Mn in the nickel-containing metal salt solution is controlled to be 95.96:4.06, and the sum of the molar concentrations of nickel ions, cobalt ions and manganese ions is 2 mol / L.

[0195] Preparation of a solution containing doped element M:

[0196] Weigh battery-grade yttrium sulfate to prepare a yttrium sulfate solution with a yttrium content of 3.56 g / L;

[0197] Weigh battery-grade sodium molybdate to prepare a sodium molybdate solution with a molybdenum content of 11.99 g / L;

[0198] Under N2 protection (oxygen content <0.5v%), a nickel-containing metal salt solution, yttrium sulfate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution were co-flowed into a reactor containing a bottom liquid for co-precipitation reaction. The stirring speed during the co-precipitation reaction was controlled at 600 rpm, the flow rate of the nickel-containing metal salt solution was 8.5% of the reactor volume / h, and the flow rate ratio of the nickel-containing metal salt solution, yttrium sulfate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (60-62):(30-31):(30-31):(22.3-23.3):1. The pH value during the co-precipitation reaction was controlled to decrease from 11.50 to 10.7 over a period of 5 h, and the ammonia concentration during the co-precipitation reaction was controlled at 3.3-3.7 g / L.

[0199] Example 9

[0200] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Zr 0.01 (OH) 1.99 (WO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0201] Weigh battery-grade sodium tungstate to prepare a sodium tungstate solution with a molybdenum content of 15.31 g / L;

[0202] Weigh the battery-grade zirconium oxysulfate to prepare a zirconium oxysulfate solution with a zirconium content of 3.65 g / L;

[0203] The pH of the substrate solution was 11.6, and the concentration of ammonia in the substrate solution was 4.5 g / L.

[0204] Under N2 protection (oxygen content <0.5v%), nickel-containing metal salt solution, magnesium sulfate solution, zirconium oxysulfate solution, sodium tungstate solution, sodium hydroxide solution, and ammonia solution are co-flowed into a reactor containing a bottom liquid for co-precipitation reaction. The flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, zirconium oxysulfate solution, sodium tungstate solution, sodium hydroxide solution, and ammonia solution during the co-precipitation reaction is controlled to be (42-44):(21-22):(21-22):(21-22):(15.9-16.3):1. The pH value decreases from 11.6 to 11.4, and the ammonia concentration during the co-precipitation reaction is controlled to be 4.8-5.2 g / L.

[0205] Comparative Example 1

[0206] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0207] The pH of the base solution was controlled at 11.1, the ammonia concentration at 7 g / L, the pH value during the coprecipitation reaction was controlled to decrease from 11.1 to 10.9, the reaction temperature was 50℃, the flow rate of the nickel metal salt solution was 7% / h of the reactor volume, and the flow rate ratio of the nickel metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution and ammonia solution was (55-57):(27.5-28.5):(27.5-28.5):(27.5-28.5):(20.7-21.3):1; the ammonia concentration during the coprecipitation reaction was controlled at 3.7-3.9 g / L.

[0208] Comparative Example 2

[0209] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0210] The pH of the base solution was controlled at 12.3, the ammonia concentration at 10 g / L, and the pH value during the coprecipitation reaction was controlled to decrease from 12.3 to 10.6 over a period of 9 hours. The reaction temperature was 60℃, the stirring speed was 1400 rpm, and the flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (43-45):(21.5-22.5):(21.5-22.5):(21.5-22.5):(16.2-16.6):1. The ammonia concentration during the coprecipitation reaction was controlled at 4.9-5.3 g / L.

[0211] Comparative Example 3

[0212] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor differs from that in Example 1 in that:

[0213] The pH of the base solution was controlled at 12.6, and the ammonia concentration was 12 g / L. The pH value during the coprecipitation reaction was controlled so that the pH value decreased from 12.6 to 11.8 over a period of 6 hours. The flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (41-43):(20.5-21.5):(20.5-21.5):(20.5-21.5):(15.4-16.0):1. The ammonia concentration during the coprecipitation reaction was controlled at 5.0-5.4 g / L.

[0214] Comparative Example 4

[0215] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 1.99 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0216] The pH of the base solution was controlled at 12.4, the ammonia concentration at 8 g / L, and the pH value during the coprecipitation reaction was controlled to decrease from 12.4 to 11.3 over a period of 9 hours. The stirring speed was 400 rpm, the flow rate of the nickel-containing metal salt solution was 12% of the reactor volume per hour, and the flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium molybdate solution, sodium hydroxide solution, and ammonia solution was (24.5-25.5):(12.2-12.7):(12.2-12.7):(12.2-12.7):(9.2-9.5):1. The ammonia concentration during the coprecipitation reaction was controlled at 8.6-9.0 g / L.

[0217] Comparative Example 5

[0218] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.07 The precursor for the positive electrode material of (OH)2 was prepared using a method similar to that in Example 1, except that:

[0219] The pH of the base solution was 11.5, and the ammonia concentration was 4.5 g / L;

[0220] Under N2 protection (oxygen content <0.5v%), a nickel-containing metal salt solution, a sodium hydroxide solution, and an ammonia solution were co-flowed into a reactor containing a bottom liquid for co-precipitation. The temperature of the co-precipitation reaction was controlled at 60℃, the stirring speed at 900 rpm, the flow rate of the nickel-containing metal salt solution at 7.5% of the reactor volume / h, and the flow rate ratio of the nickel-containing metal salt solution, sodium hydroxide solution, and ammonia solution at (47-49):(17.8-18.2):1. The pH value of the co-precipitation reaction was controlled to decrease from 11.5 to 11.3 over a period of 3 hours. The ammonia concentration during the co-precipitation reaction was controlled at 4.3-4.7 g / L.

[0221] Comparative Example 6

[0222] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.04 Mg 0.02 Nb 0.01 (OH) 2.03 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0223] The pH of the base solution was controlled at 11.9, and the ammonia concentration was 5 g / L.

[0224] Under N2 protection (oxygen content <0.5v%), nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium hydroxide solution, and ammonia solution were co-flowed into a reactor containing a bottom liquid for co-precipitation reaction. The stirring speed of the co-precipitation reaction was controlled at 1000 rpm, the flow rate of the nickel-containing metal salt solution was 6% / h of the reactor volume, and the flow rate ratio of the nickel-containing metal salt solution, magnesium sulfate solution, niobium oxalate solution, sodium hydroxide solution, and ammonia solution was (41-43):(20.5-21.5):(20.5-21.5):(15.4-16.0):1. The pH value of the co-precipitation reaction was controlled to decrease from 11.9 to 11.3 over a period of 9 h, and the ammonia concentration was controlled to be 4.3-4.7 g / L.

[0225] Comparative Example 7

[0226] Prepare a chemical formula Ni 0.84 Co 0.09 Mn 0.07 (OH) 1.96 (MoO4) 0.02 The cathode material precursor was prepared using a method similar to that in Example 1, except that:

[0227] The pH of the base solution was 11.9, and the ammonia concentration was 4.5 g / L;

[0228] Under N2 protection (oxygen content <0.5v%), a nickel-containing metal salt solution, sodium tungstate solution, sodium hydroxide solution, and ammonia solution were co-flowed into a reactor containing a bottom liquid for co-precipitation reaction. The flow rate of the nickel-containing metal salt solution during the co-precipitation reaction was controlled at 6% / h of the reactor volume, and the flow rate ratio of the nickel-containing metal salt solution, sodium tungstate solution, sodium hydroxide solution, and ammonia solution was (43-45):(21.5-22.5):(16.2-16.6):1. The stirring speed of the co-precipitation reaction was controlled at 1000 rpm, the pH value decreased from 11.9 to 11.3 over a period of 9 h, and the ammonia concentration during the co-precipitation reaction was controlled at 4.8-5.2 g / L.

[0229] Test Example 1

[0230] The cathode material precursors prepared in the aforementioned embodiments and comparative examples were tested, specifically:

[0231] 1. Using a Cu-Kα X-ray diffractometer (model Bruker D8Advance), the full width at half maximum (FWHM) of each crystal plane is obtained by powder X-ray diffraction of Cu-Kα rays. Then, the grain size of each crystal plane is calculated by Scherrer formula or professional software.

[0232] 2. Particle size (D50, D90, D10) was tested using a Malvern 3000 laser particle size analyzer, and determined in accordance with the national standard GB / T19077-2016 Particle Size Analysis by Laser Diffraction.

[0233] 3. Specific surface area (BET) was determined using a fully automated nitrogen adsorption specific surface area analyzer (instrument model: BELPREP-VACII / BELSORP-MINI-X) in accordance with the national standard GB / T 19587-2017 Determination of specific surface area of ​​solid substances by gas adsorption BET method.

[0234] 4. Tap density (TD) was determined using a powder tap density tester (model: Dandong Baite BT-302) in accordance with the national standard GB / T 5162-2021 "Determination of Tap Density of Metal Powders";

[0235] 5. Content of nickel, cobalt, manganese, etc.: determined by inductively coupled plasma mass spectrometry (instrument model: Agilent 7850ICP-MS), referring to the national standard GB / T 8647.11-2019 Chemical analysis method for nickel - Part 11: Determination of the content of magnesium, aluminum, manganese, cobalt, copper, zinc, cadmium, tin, antimony, lead and bismuth by inductively coupled plasma mass spectrometry.

[0236] The present invention provides, by way of example, XRD patterns corresponding to the XRD test data of Embodiment 1, Embodiment 2, and Comparative Examples 1-3, as shown in the figures below. Figures 1-5 As shown, by Figures 1-5 By combining specialized software calculations, we can obtain the grain size, peak intensity ratio, and other parameters corresponding to each crystal facet of the cathode material precursor obtained in each example.

[0237] The test results are shown in Tables 1 and 2:

[0238] Table 1

[0239]

[0240]

[0241] Table 2

[0242]

[0243] Test Example 2

[0244] Preparation of cathode materials for lithium-ion batteries:

[0245] The cathode material precursor prepared in the aforementioned example is mixed evenly with lithium carbonate to obtain a mixture;

[0246] The molar ratio of Li to the total of other metal elements (excluding Li) in the mixture is controlled to be 1.05:1;

[0247] The mixture is sintered in an oxygen atmosphere to obtain the lithium-ion battery cathode material.

[0248] The sintering temperature was 950℃ and the time was 5 hours.

[0249] Test Example 3

[0250] Preparation of lithium-ion batteries (button cell model CR-2032 half-cell):

[0251] (1) Preparation of positive electrode sheet: The lithium-ion battery positive electrode material obtained in Test Example 2 was mixed with conductive acetylene black and binder in a mass ratio of 8:1:1 to obtain a slurry. The slurry was uniformly coated on the surface of aluminum foil using a 200μm doctor blade and a coating machine. The coated aluminum foil was then dried, pressed three times by a roller press, and cut into a circle with a diameter of 15mm. The circle was then transferred to a vacuum oven in a glove box to dry, thus obtaining the positive electrode sheet.

[0252] (2) Battery assembly: The positive electrode, negative electrode (lithium metal) and separator are wound into battery cores and then installed into the battery steel shell. Then, the battery is sequentially grooved, coated with sealing oil, welded with battery caps and filled with electrolyte to seal the opening. Finally, the battery is sorted and assembled.

[0253] The assembled battery was subjected to its first discharge (3.0-4.3V) at room temperature (25℃) to test the discharge capacity at 0.1C and 1.5C rates, where 1C = 200mAh / g. The results are shown in Table 3.

[0254] Table 3

[0255]

[0256] The cathode material precursors provided in Examples 1-9 of this invention were tested by Cu-Kα X-ray diffraction and calculated using specialized software. The grain size D on the (001) crystal plane was determined to be... (001) Small And the grain size D of the (100) crystal plane (100) The grain size D of the (001) crystal plane (001) The ratio D (100) / D (001) Within a suitable range (6.1-9.8), its application in lithium-ion batteries can improve Li... + The improved mobility resulted in lithium-ion batteries with excellent capacity and rate performance, as well as good cycle performance.

[0257] Compared to Example 1, the battery prepared from the cathode material precursor product of Comparative Example 1 exhibited poorer capacity retention after 100 cycles at 1C. The likely reason is D. (001) The value is too small; the battery prepared from the cathode material precursor product of Comparative Example 2 exhibits poor initial charge and discharge capacity at 0.1C and poor rate performance at 1.5C / 0.1C. The possible reason is D. (001) Too high, D (100) / D (001) The value is too low; the battery prepared from the cathode material precursor product of Comparative Example 3 exhibits poor initial charge and discharge capacity at 0.1C and poor rate performance at 1.5C / 0.1C. The possible reason is D. (100) / D (001) Too low; the battery prepared from the cathode material precursor product of Comparative Example 4 showed poor capacity retention after 100 cycles at 1C, which is speculated to be due to D. (100) / D (001) The values ​​are too high; Comparative Examples 5-7, prepared from undoped cathode material precursors, undoped metal molybdate ion cathode material precursors, and undoped metal cation cathode material precursors respectively, showed poor initial charge and discharge capacity at 0.1C and poor rate performance at 1.5C / 0.1C. The possible reason is that the corresponding D... (001) Larger grain size, D (100) / D (001) The ratio is too small.

[0258] Examples 1-4 used 8-series triple-doped (Mg, Nb, Mo) cathode material precursors, and the batteries prepared from these precursors exhibited high capacity and rate performance. Compared to Example 4, the cathode material precursor prepared in Example 5, when used to prepare a battery, showed slightly lower initial charge and discharge capacity at 0.1C, slightly lower rate performance at 1.5C / 0.1C, and slightly better capacity retention after 100 cycles at 1C. The likely reason for this is D... (101) The value is slightly higher. Compared to Example 1, the cathode material precursor prepared in Example 6, when used to fabricate a battery, exhibits slightly better initial charge and discharge capacity at 0.1C and better rate performance at 1.5C / 0.1C. However, its capacity retention after 100 cycles at 1C is slightly worse. The likely reason is D. (101) The results are relatively low. Example 7 is a 7-series quadruple-doped (Al, Zr, Nb, Mo) cathode material precursor product, Example 8 is a large-particle 9-series dual-doped (Y, Mo) cathode material precursor product, and Example 9 is an 8-series triple-doped (Mg, Zr, W) cathode material precursor product. The electrochemical performance of the batteries prepared from these products differs, which is presumably due to the influence of element content, resulting in differences in corresponding grain sizes.

[0259] The optional embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A cathode material precursor, characterized in that, The cathode material precursor is a nickel-containing hydroxide; The grain size D of the cathode material precursor on the (001) crystal plane (001) for The precursor of the cathode material has a grain size D on the (100) crystal plane. (100) and the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-9.8; Wherein, the (001) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 18.0° to 20.0°; the (100) crystal plane corresponds to a diffraction peak at a diffraction angle 2θ of 32.0° to 34.0°.

2. The cathode material precursor according to claim 1, characterized in that, The (101) crystal plane of the cathode material precursor corresponds to a diffraction peak at a diffraction angle 2θ of 37.5° to 39.5°, and the cathode material precursor satisfies at least one of the following conditions: A. The grain size D of the cathode material precursor on the (101) crystal plane. (101) for Optionally, D (101) for B. The grain size D of the cathode material precursor on the (100) crystal plane (100) and the grain size D on the (101) crystal plane (101) The ratio D (100) / D (101) The value is 3.0-6.5; optionally, D (100) / D (101) The value is 3.2-6.

3.

3. The cathode material precursor according to claim 1, characterized in that, The (101) crystal plane of the cathode material precursor corresponds to a diffraction peak at a diffraction angle 2θ of 37.5° to 39.5°, and the cathode material precursor satisfies at least one of the following conditions: A. The grain size D of the cathode material precursor on the (001) crystal plane. (001) for B. The grain size D of the cathode material precursor on the (100) crystal plane (100) for Optionally, D (100) for C. The grain size D of the cathode material precursor on the (100) crystal plane. (100) and the grain size D on the (001) crystal plane (001) The ratio D (100) / D (001) The range is 6.1-8.8; D. The grain size D of the cathode material precursor on the (101) crystal plane. (101) and the grain size D on the (001) crystal plane (001) The ratio D (101) / D (001) The value is 1.2-2.0; optionally, D (101) / D (001) It is 1.2-1.7; E. The peak intensity ratio I of the cathode material precursor on the (101) crystal plane and on the (001) crystal plane. (101) / I (001) It is 1.1-1.5; optionally, I (101) / I (001) It is 1.1-1.

4.

4. The cathode material precursor according to any one of claims 1-3, characterized in that, The precursor satisfies at least one of the following conditions: A. The average particle size D50 of the cathode material precursor is 2μm-18μm; B. The particle size distribution of the cathode material precursor is Span = (D90 - D10) / D50 = 1.2 - 1.6; C. The specific surface area (BET) of the cathode material precursor is 20m². 2 / g-40m 2 / g; D. The tap density TD of the cathode material precursor is 1.2 g / m³. 3 -2.0m 2 / g; E. The molar ratio of nickel content to total metal content in the cathode material precursor is ≥50 mol%. F. The chemical formula of the cathode material precursor is Ni. a Co b Mn c M d (OH) e (XO4) f Wherein, 0.6≤a<1, 0≤b≤0.3, 0≤c≤0.2, 0≤d≤0.2, 1.7≤e≤2.3, 0≤f<0.2, a+b+c+d=1, M is at least one of Mg, Nb, Zr, Y, Al, Zn, Ti, Sr; X is Mo and / or W.

5. A method for preparing the cathode material precursor according to any one of claims 1-4, characterized in that, The method includes: under an inert atmosphere, adding a nickel-containing metal salt solution, a precipitant solution, and a complexing agent solution in parallel to a reactor containing a bottom liquid to carry out a co-precipitation reaction; controlling the pH value of the co-precipitation reaction to first decrease and then maintain it within a certain range until the material in the reactor grows to the target particle size; collecting the overflow solution for post-processing to obtain the cathode material precursor. The base liquid is a mixture of water, the precipitant solution, and the complexing agent solution; the oxygen content of the inert atmosphere in the reactor is controlled to be <0.5v.

6. The method according to claim 5, characterized in that, The method satisfies at least one of the following conditions: a. The pH value of the base solution is 11.4-12.0; b. The ammonia concentration in the substrate solution is 3g / L-9g / L; c. A solution containing a dopant element M is also introduced concurrently into the bottom liquid, wherein the dopant element M is at least one of Al, Ti, Zr, Mo, Cr, W, Mg, Ba, Nb or Sr; d. A solution containing dopant element M is also introduced concurrently into the bottom liquid, wherein the mass concentration of dopant element M in the solution containing dopant element M is independently 2 g / L-11 g / L. e. A solution containing anion X is also introduced concurrently into the bottom liquid, wherein the anion X is Mo. 6+ and / or W 6+ ; f. A solution containing anion X is also introduced concurrently into the base liquid, wherein the mass concentration of anion X in the solution containing anion X is 3 g / L-18 g / L. g. Control the flow rate of the nickel-containing metal salt solution during the co-precipitation reaction to be 4%-10% of the reactor volume per hour. h. Controlling the flow rate ratio of the nickel-containing metal salt solution to the precipitant solution in the co-precipitation reaction to be (2.4-3.0):1; i. Control the flow rate ratio of the precipitant solution to the complexing agent solution in the coprecipitation reaction to be (10-23):1; j. Control the pH value of the coprecipitation reaction to decrease from 11.4-12.0 to 10.6-11.5; k. Control the pH value of the coprecipitation reaction to decrease over a period of 2-5 hours; l. Control the ammonia concentration in the co-precipitation reaction to be 2 g / L-10 g / L.

7. The method according to claim 5 or 6, characterized in that, The method satisfies at least one of the following conditions: a. The precipitant solution includes sodium hydroxide; b. The mass fraction of the precipitant in the precipitant solution is 20wt%-40wt%; c. The complexing agent solution includes ammonia water; d. The mass fraction of the complexing agent in the complexing agent solution is 10wt%-30wt%; e. The nickel-containing metal salt solution also includes cobalt ions and / or manganese ions; f. The sum of the molar concentrations of each metal ion in the nickel-containing metal salt solution is 1 mol / L to 3 mol / L; g. Control the temperature of the coprecipitation reaction to be 55℃-65℃; h. Control the stirring speed of the precipitation reaction to be 500 rpm-1000 rpm.

8. A lithium-ion battery cathode material, characterized in that, The raw materials for the lithium-ion battery cathode material include the cathode material precursor as described in any one of claims 1-4.

9. A lithium-ion battery, characterized in that, Including the lithium-ion battery cathode material as described in claim 8.

10. An electrical-related device, characterized in that, Including the lithium-ion battery as described in claim 9.

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