A high-nickel hydroxyl oxide precursor, a preparation method and application thereof

Abstract

The application provides a high-nickel hydroxyl oxide precursor and a preparation method and application thereof, and the preparation method comprises the following steps: adding a mixed metal salt solution, a precipitant solution, a complexing agent solution and an oxidizing agent solution into a reaction bottom liquid in parallel flow to perform a coprecipitation reaction, stopping feeding when a target median particle size D50 is reached, and obtaining the high-nickel hydroxyl oxide precursor; the mixed metal salt solution comprises a first metal element and a second metal element, the first metal element is Ni, and the second metal element comprises Mn and / or Co. The preparation process of the application adds the oxidizing agent solution into the reaction raw material in parallel flow to perform the coprecipitation reaction, can realize one-step preparation of the high-nickel hydroxyl oxide precursor rich in trivalent nickel, and has good structural stability; when used for preparing a high-nickel positive electrode material, the high-nickel positive electrode material can be reduced in charge-discharge volume strain, and long cycle performance can be improved; in addition, the one-step coprecipitation method simplifies the production process, improves the preparation efficiency, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of high-nickel precursor preparation technology, and in particular to a high-nickel hydroxyl oxide precursor, its preparation method, and its application. Background Technology

[0002] With the increasing demands for energy density from electric vehicles, large-scale energy storage, and portable electronic devices, developing cathode materials with high specific capacity, high operating voltage, and good cycle stability has become the core of lithium-ion battery technology development. Among numerous cathode materials, layered high-nickel cathode materials (such as LiNi) are particularly important. x M y O2 (x≥0.8, x+y=1, M can be transition metals such as Mn and Co) is considered a key material for achieving battery energy densities of over 300Wh / kg due to its advantages such as high reversible specific capacity (discharge specific capacity can reach 180-220mAh / g), high operating voltage, relatively low cost, and high compatibility with anode materials.

[0003] Layered high-nickel cathode materials exhibit significant valence state changes during charging-to-delithiation and discharging-to-lithiation processes due to their extremely high Ni content. 2＋ and Ni 4＋ The interconversion between these elements causes drastic changes in ionic radius and a volume change rate far greater than that of low- and medium-nickel cathode materials. This manifests as overall particle volume expansion and contraction, making them more prone to internal stress, microcracks, and pulverization. Therefore, ensuring structural stability is crucial for reducing charge-discharge volume strain. As the foundation for preparing layered high-nickel cathode materials, the structural stability of the precursor largely determines the performance of these materials. Studies have shown that compared to traditional hydroxide precursors (where Ni mainly exists in the +2 valence state), hydroxyl oxide precursors (where Ni mainly exists in the +3 valence state) are a more ideal precursor choice for layered high-nickel cathode materials due to their unique structural and valence state advantages. Taking ternary nickel-cobalt-manganese hydroxyl oxide (NCMOOH) precursor as an example, it has the following advantages: First, it has a more stable and regular structure with more ordered primary particle arrangement; second, Ni mainly exists in the +3 valence state in the precursor, and Co and Mn are also mainly in the high valence state, which is more consistent with the valence state of the target cathode material, and the Li / Ni mixing is greatly reduced during lithiation sintering; third, the surface activity and residual alkali content are lower, reducing side reactions with the electrolyte; fourth, the volume change is more uniform during the preparation of cathode materials, with fewer intergranular cracks and denser secondary particles.

[0004] However, existing technologies still have significant limitations and shortcomings in the efficient and controllable preparation of hydroxyl oxide precursors. Currently, the mainstream preparation routes for hydroxyl oxide precursors are mostly two-step methods: first, a hydroxide precursor is prepared, and then it is post-oxidized using an oxidizing agent solution. For example, CN108777291A discloses the method of ball milling NCM811 precursor powder with Mn2O7 and Na2S2O8 under argon protection to obtain NCMOOH. Another method discloses the use of Ni... 0.83 Co 0.05 Mn 0.12 Ni is obtained by reacting (OH)₂ precursor powder with NaClO solution at a certain temperature. 0.83 Co 0.05 Mn 0.12 The two-step process described above (OOH) generally suffers from problems such as lengthy processes, complex procedures, and poor controllability. In the post-oxidation process, uneven oxidation and asynchronous internal and external oxidation are prone to occur. That is, while the surface can achieve complete oxidation, the high mass transfer resistance inside the particles and the difficulty in rapid penetration of the oxidant result in a significantly lower degree of internal oxidation, leaving a large amount of incompletely oxidized Ni. 2＋ This leads to problems such as poor crystal integrity, disordered local structure, and chaotic valence state distribution in the hydroxyl oxide precursor, which has a limited effect on improving the structural stability of the obtained high-nickel cathode material.

[0005] Therefore, how to provide a high-nickel precursor rich in trivalent nickel with simple processing and uniform element distribution, good structural stability, and suitable for preparing high-nickel cathode materials, which can reduce the volume strain of high-nickel cathode materials during charging and discharging, is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a high-nickel hydroxyl oxide precursor, its preparation method, and its applications. The preparation process of this invention involves adding an oxidant solution concurrently with the reactants for a co-precipitation reaction, enabling the one-step preparation of a high-nickel hydroxyl oxide precursor rich in trivalent nickel with good structural stability. When used to prepare high-nickel cathode materials, it can reduce the charge-discharge volumetric strain of the high-nickel cathode material, improving its long-cycle performance. Furthermore, the one-step co-precipitation method simplifies the production process, improves preparation efficiency, and is suitable for large-scale production.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a high-nickel hydroxyl oxide precursor, the method comprising the following steps: A mixed metal salt solution, precipitant solution, complexing agent solution and oxidant solution are added concurrently to the reaction substrate to carry out a co-precipitation reaction. Once the target median particle size D50 is reached, the feeding is stopped to obtain a high-nickel hydroxyl oxide precursor. The mixed metal salt solution includes a first metal element and a second metal element, wherein the first metal element is Ni and the second metal element includes Mn and / or Co.

[0008] The preparation process of this invention involves adding the oxidant solution in parallel with the reactants for a co-precipitation reaction, which can achieve one-step preparation of a high-nickel hydroxyl oxide precursor rich in trivalent nickel. This precursor has good structural stability and can be used to prepare high-nickel cathode materials. It can reduce the volume strain of the high-nickel cathode material during charge and discharge and improve its long-cycle performance.

[0009] This invention employs a one-step co-precipitation method to prepare a high-nickel hydroxyl oxide precursor rich in trivalent nickel, simplifying the production process, improving preparation efficiency, and making it suitable for large-scale production. It also achieves more uniform oxidation of divalent nickel and facilitates complete oxidation to trivalent nickel. Compared to first preparing a high-nickel precursor rich in divalent nickel (Ni... x M y This invention uses a two-step method to prepare (OH)2, which is then oxidized by mixing with an oxidizing agent solution. This method avoids the phenomenon that only the surface of the precursor is oxidized to produce trivalent nickel, while the internal oxidation is incomplete.

[0010] As a preferred embodiment of the present invention, the second metallic element includes Mn and Co.

[0011] Preferably, the oxidant solution comprises sodium persulfate solution and / or hydrogen peroxide solution.

[0012] Preferably, the concentration of the oxidant solution is 0.1 g / L to 2.5 g / L, such as 0.1 g / L, 0.3 g / L, 0.5 g / L, 0.8 g / L, 1 g / L, 1.2 g / L, 1.5 g / L, 1.8 g / L, 2 g / L, 2.2 g / L, or 2.5 g / L.

[0013] Preferably, the feed rate of the oxidant solution is 0.1L / h-1L / h, such as 0.1L / h, 0.2L / h, 0.3L / h, 0.4L / h, 0.5L / h, 0.6L / h, 0.7L / h, 0.8L / h, 0.9L / h, or 1L / h.

[0014] As a preferred embodiment of the present invention, the total mass concentration of metal elements in the mixed metal salt solution is 80 g / L-120 g / L, such as 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L or 120 g / L.

[0015] Preferably, the mixed metal salt solution includes at least one of sulfate solution, nitrate solution or chloride solution.

[0016] Preferably, the precipitant solution comprises a sodium hydroxide solution.

[0017] Preferably, the mass concentration of the precipitant solution is 10wt%-30wt%, for example, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, or 30wt%.

[0018] Preferably, the complexing agent solution comprises an aqueous ammonia solution.

[0019] Preferably, the mass concentration of the complexing agent solution is 10wt%-20wt%, for example, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%.

[0020] As a preferred technical solution of the present invention, the feeding rate of the mixed metal salt solution is 1L / h-10L / h, such as 1L / h, 2L / h, 3L / h, 4L / h, 5L / h, 6L / h, 7L / h, 8L / h, 9L / h or 10L / h.

[0021] Preferably, the feed rate of the precipitant solution is 1L / h-7L / h, such as 1L / h, 2L / h, 3L / h, 4L / h, 5L / h, 6L / h or 7L / h.

[0022] Preferably, the feeding rate of the complexing agent solution is 0.1L / h-1L / h, such as 0.1L / h, 0.2L / h, 0.3L / h, 0.4L / h, 0.5L / h, 0.6L / h, 0.7L / h, 0.8L / h, 0.9L / h or 1L / h.

[0023] As a preferred embodiment of the present invention, the ammonia concentration in the reaction substrate is 0 g / L-10 g / L and is not 0, for example, 0.1 g / L, 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 or 10 g / L.

[0024] Preferably, the temperature of the reaction substrate is 20℃-80℃, such as 20℃, 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃.

[0025] Preferably, the pH of the reaction substrate is 8-12, such as 8, 9, 10, 11 or 12.

[0026] As a preferred technical solution of the present invention, the stirring rate of the coprecipitation reaction is 100r / min-400r / min, for example, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min or 400r / min.

[0027] Preferably, the pH of the reaction system in the coprecipitation reaction is 8-12.5, such as 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12 or 12.5.

[0028] Preferably, the ammonia concentration in the reaction system during the coprecipitation reaction is 0 g / L to 13 g / L and is not 0, for example, 0.1 g / L, 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, or 13 g / L.

[0029] Preferably, the temperature of the reaction system in the coprecipitation reaction is 20℃-80℃, such as 20℃, 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃.

[0030] Preferably, the concentration of the oxidant in the reaction system during the coprecipitation reaction is 0.3 g / L to 1 g / L, such as 0.3 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, or 1 g / L.

[0031] This invention controls the concentration of oxidant in the reaction system during the co-precipitation reaction by adjusting the feed rate of the oxidant solution to 0.1 L / h-1 L / h, thereby achieving a better effect of complete oxidation on both the surface and inside. If the feed rate is too low, the concentration of oxidant in the reaction system will be too low, resulting in poor oxidation and failure to guarantee complete oxidation; if the feed rate is too high, it will lead to waste of oxidant and increased costs.

[0032] Preferably, the target median particle size D50 is 1μm-50μm, such as 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm, etc.

[0033] Preferably, after the feed is stopped, the raw materials are allowed to react completely, followed by solid-liquid separation, washing, and drying to obtain a high-nickel hydroxyl oxide precursor.

[0034] Secondly, the present invention also provides a high-nickel hydroxyl oxide precursor, which is prepared according to the preparation method described in the first aspect, and the general chemical formula of the high-nickel hydroxyl oxide precursor is M. x N y OOH, where M is Ni, N includes Mn and / or Co, x+y=1, 0.8≤x<1, for example 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98 or 0.99, etc.

[0035] As a preferred embodiment of the present invention, the N includes Mn and Co.

[0036] Thirdly, the present invention also provides a high-nickel cathode material, which is prepared using a high-nickel hydroxyl oxide precursor and a lithium salt as described in the second aspect.

[0037] Fourthly, the present invention also provides a method for preparing the high-nickel cathode material according to the third aspect, the method comprising the following steps: A high-nickel hydroxyl oxide precursor and a lithium salt are mixed evenly and then sintered to obtain a high-nickel cathode material.

[0038] As a preferred technical solution of the present invention, the molar ratio of the high-nickel hydroxyl oxide precursor to the lithium salt is 1:(1-2), such as 1:1, 1:1.2, 1:1.5, 1:1.8 or 1:2, etc.

[0039] Preferably, the lithium salt comprises LiOH·H2O and / or lithium carbonate.

[0040] Preferably, the sintering temperature is 600℃-800℃, such as 600℃, 650℃, 700℃, 750℃ or 800℃.

[0041] Preferably, the sintering time is 6h-15h, such as 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h or 15h.

[0042] Preferably, the sintering is carried out in an air atmosphere.

[0043] Preferably, the sintering process further includes crushing and sieving.

[0044] Fifthly, the present invention also provides a lithium-ion battery, the lithium-ion battery comprising the high-nickel cathode material as described in the third aspect, or the high-nickel cathode material prepared by the preparation method described in the fourth aspect.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects: 1) The preparation process of this invention involves adding the oxidant solution in parallel with the reactants for co-precipitation reaction, which can achieve one-step preparation of a high-nickel hydroxyl oxide precursor rich in trivalent nickel with good structural stability. When used to prepare high-nickel cathode materials, it can reduce the volume strain of high-nickel cathode materials during charge and discharge and improve long-cycle performance.

[0046] 2) This invention employs a one-step co-precipitation method to prepare a high-nickel hydroxyl oxide precursor rich in trivalent nickel, simplifying the production process, improving preparation efficiency, and making it suitable for large-scale production. It also achieves more uniform oxidation of divalent nickel and facilitates complete oxidation to trivalent nickel. Compared to first preparing a high-nickel precursor rich in divalent nickel (Ni... x M y This invention uses a two-step method to prepare (OH)2, which is then oxidized by mixing with an oxidizing agent solution. This method avoids the phenomenon that only the surface of the precursor is oxidized to produce trivalent nickel, while the internal oxidation is incomplete. Attached Figure Description

[0047] Figure 1 The Ni provided in Embodiment 1 of the present invention 0.98 Co 0.01 Mn 0.01 SEM image of the OOH high-nickel hydroxyl oxide precursor.

[0048] Figure 2 The Ni provided in Comparative Example 1 of this invention 0.98 Co 0.01 Mn 0.01 SEM image of the (OH)2 high-nickel hydroxide precursor. Detailed Implementation

[0049] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0050] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0051] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0052] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0053] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0054] Example 1 This embodiment provides a method for preparing a high-nickel hydroxide precursor, the method comprising the following steps: A nickel-cobalt-manganese ternary mixed sulfate solution with a total metal element concentration of 100 g / L, a sodium hydroxide solution with a mass concentration of 20 wt%, an ammonia solution with a mass concentration of 15 wt%, and a sodium persulfate solution with a mass concentration of 1 g / L were simultaneously and concurrently added to a reaction substrate (a mixture of pure water and ammonia, with the volume of the reaction substrate being 2 / 3 of the reactor volume) at a temperature of 50℃, an ammonia concentration of 5 g / L, and a pH of 11.6. The coprecipitation reaction was carried out at a stirring rate of r / min. During the reaction, the pH of the reaction system was maintained at 11-11.2, the ammonia concentration was 4.5 g / L, the sodium persulfate concentration was 0.8 g / L, and the temperature was 50℃. The particle size was continuously monitored. Before the required particle size was reached, a high-efficiency thickener was used to collect all the particles and return them to the reactor for continued reaction and growth. When the median particle size D50 reached 2.5 μm, the feed was stopped, and the reaction continued until the reactants were completely reacted. After filtration, washing, and drying, Ni was obtained. 0.98 Co 0.01 Mn 0.01 OOH.

[0055] This embodiment also provides a method for preparing a high-nickel cathode material, the method comprising the following steps: The above Ni 0.98 Co 0.01 Mn 0.01 OOH and LiOH·H2O were mixed uniformly in a molar ratio of 1:1.5 using a high-speed mixer. The mixture was then sintered in an air atmosphere using a box furnace at 700℃ for 10 hours. After cooling to room temperature, the mixture was pulverized and sieved to obtain LiNi. 0.98 Co 0.01 Mn 0.01 O2 cathode material.

[0056] Example 2 This embodiment provides a method for preparing a high-nickel hydroxide precursor, the method comprising the following steps: A nickel-cobalt-manganese ternary mixed sulfate solution with a total metal element concentration of 80 g / L, a sodium hydroxide solution with a mass concentration of 10 wt%, an ammonia solution with a mass concentration of 10 wt%, and a hydrogen peroxide solution with a mass concentration of 2.5 g / L were simultaneously and concurrently added to a reaction substrate (a mixture of pure water and ammonia, with the volume of the reaction substrate being 2 / 3 of the reactor volume) at a temperature of 20°C, an ammonia concentration of 3 g / L, and a pH of 9. The coprecipitation reaction was carried out at a stirring rate of 0 r / min. During the reaction, the pH of the reaction system was maintained at 8.5-8.7, the ammonia concentration was 3 g / L, the hydrogen peroxide solution concentration was 1 g / L, and the temperature was 20℃. The particle size was continuously monitored. Before the required particle size was reached, a high-efficiency thickener was used to collect all the particles and return them to the reactor for continued reaction and growth. When the median particle size D50 reached 3 μm, the feed was stopped, and the reaction continued until the reactants were completely reacted. After filtration, washing, and drying, Ni was obtained. 0.9 Co 0.05 Mn 0.05 OOH.

[0057] This embodiment also provides a method for preparing a high-nickel cathode material, the method comprising the following steps: The above Ni 0.9 Co 0.05 Mn 0.05 OOH and LiOH·H2O were mixed uniformly in a 1:1 molar ratio using a high-speed mixer. The mixture was then sintered in an air atmosphere using a box furnace at 600℃ for 15 hours. After cooling to room temperature, the mixture was pulverized and sieved to obtain LiNi. 0.9 Co 0.05 Mn 0.05 O2 cathode material.

[0058] Example 3 This embodiment provides a method for preparing a high-nickel hydroxide precursor, the method comprising the following steps: A nickel-cobalt-manganese ternary mixed sulfate solution with a total metal element concentration of 120 g / L, a sodium hydroxide solution with a mass concentration of 30 wt%, an ammonia solution with a mass concentration of 20 wt%, and a sodium persulfate solution with a mass concentration of 2 g / L were simultaneously and concurrently added to a reaction substrate (a mixture of pure water and ammonia, the volume of which was 2 / 3 of the reactor volume) at a temperature of 80℃, an ammonia concentration of 7 g / L, and a pH of 12. The reaction substrate was fed at 40℃. The coprecipitation reaction was carried out at a stirring rate of 0 r / min. During the reaction, the pH of the reaction system was controlled at 12.3-12.5, the ammonia concentration at 5 g / L, the sodium persulfate concentration at 1 g / L, and the temperature at 80℃. The particle size was continuously monitored. Before the required particle size was reached, a high-efficiency thickener was used to collect all the particles and return them to the reactor for continued reaction and growth. When the median particle size D50 reached 5 μm, the feed was stopped, and the reaction continued until the reactants were completely reacted. After filtration, washing, and drying, Ni was obtained. 0.85 Co 0.1 Mn 0.05 OOH.

[0059] This embodiment also provides a method for preparing a high-nickel cathode material, the method comprising the following steps: The above Ni 0.85 Co 0.1 Mn 0.05 OOH and LiOH·H2O were mixed uniformly in a molar ratio of 1:2 using a high-speed mixer. The mixture was then sintered in an air atmosphere using a box furnace at 800℃ for 6 hours. After cooling to room temperature, the mixture was pulverized and sieved to obtain LiNi. 0.85 Co 0.1 Mn 0.05 O2 cathode material.

[0060] Example 4 This embodiment provides a method for preparing a high-nickel hydroxyl oxide precursor. The difference between this method and Example 1 is that the nickel-cobalt-manganese ternary mixed sulfate solution with a total metal element concentration of 100 g / L is replaced with a nickel-cobalt binary mixed sulfate solution with a total metal element concentration of 100 g / L, thus preparing Ni 0.98 Co 0.02 OOH, the rest of the preparation methods and parameters are consistent with those in Example 1.

[0061] This embodiment also provides a method for preparing a high-nickel cathode material. The difference between this method and that of Example 1 is that Ni is used. 0.98 Co 0.02 Using OOH as a precursor, LiNi was prepared. 0.98 Co 0.02The O2 cathode material was prepared using the same methods and parameters as in Example 1.

[0062] Example 5 This embodiment provides a method for preparing a high-nickel hydroxyl oxide precursor. The difference between this method and Example 1 is that the ternary mixed sulfate solution with a total metal element concentration of 100 g / L is replaced with a binary mixed sulfate solution with a total metal element concentration of 100 g / L, to prepare Ni 0.98 Mn 0.02 OOH, the rest of the preparation methods and parameters are consistent with those in Example 1.

[0063] This embodiment also provides a method for preparing a high-nickel cathode material. The difference between this method and that of Example 1 is that Ni is used. 0.98 Mn 0.02 Using OOH as a precursor, LiNi was prepared. 0.98 Mn 0.02 The O2 cathode material was prepared using the same methods and parameters as in Example 1.

[0064] Example 6 This embodiment provides a method for preparing a high-nickel hydroxyl oxide precursor. The difference between this method and Example 1 is that the feed rate of the sodium persulfate solution is 0.05 L / h, the concentration of sodium persulfate in the reaction system is 0.1 g / L, and the rest of the preparation method and parameters are the same as in Example 1.

[0065] This embodiment also provides a method for preparing a high-nickel cathode material. The difference between this method and that of Example 1 is that the LiNi cathode material is prepared using the precursor provided in this embodiment. 0.98 Co 0.01 Mn 0.01 The O2 cathode material was prepared using the same methods and parameters as in Example 1.

[0066] Example 7 This embodiment provides a method for preparing a high-nickel hydroxyl oxide precursor. The difference between this method and Example 1 is that the feed rate of the sodium persulfate solution is 1.2 L / h, the concentration of sodium persulfate in the reaction system is 2.4 g / L, and the rest of the preparation method and parameters are the same as in Example 1.

[0067] This embodiment also provides a method for preparing a high-nickel cathode material. The difference between this method and that of Example 1 is that the LiNi cathode material is prepared using the precursor provided in this embodiment. 0.98 Co 0.01 Mn 0.01 The O2 cathode material was prepared using the same methods and parameters as in Example 1.

[0068] Comparative Example 1 This comparative example provides a method for preparing a high-nickel hydroxide precursor. The difference between this method and Example 1 is that the co-current addition of sodium persulfate solution is omitted, resulting in the preparation of Ni... 0.98 Co 0.01 Mn 0.01 (OH)2, the rest of the preparation methods and parameters are consistent with those in Example 1.

[0069] This comparative example provides a method for preparing a high-nickel cathode material. The difference between this method and Example 1 is that it uses Ni... 0.98 Co 0.01 Mn 0.01 LiNi was prepared using (OH)2 as a precursor. 0.98 Co 0.01 Mn 0.01 The O2 cathode material was prepared using the same methods and parameters as in Example 1.

[0070] Figure 1 The Ni provided in Embodiment 1 of the present invention is shown. 0.98 Co 0.01 Mn 0.01 SEM image of the OOH high-nickel hydroxyl oxide precursor. Figure 2 The present invention provides a Ni according to Comparative Example 1. 0.98 Co 0.01 Mn 0.01 SEM images of the (OH)2 high-nickel hydroxide precursor show that the precursor in Example 1 has a regular structure, with primary particles being irregular scaly. This contrasts with the Ni in Comparative Example 1. 0.98 Co 0.01 Mn 0.01 The (OH)2 precursor showed a clear difference, indicating that the +2 valence nickel was oxidized, and a high nickel hydroxyl oxide precursor was successfully prepared.

[0071] Comparative Example 2 This comparative example provides a method for preparing a high-nickel hydroxyl oxide precursor. The difference between this method and Example 1 is that the co-current addition of sodium persulfate solution is omitted, resulting in the preparation of Ni... 0.98 Co 0.01 Mn 0.01 (OH)2, then Ni 0.98 Co 0.01 Mn 0.01 (OH)₂ and 10 g / L sodium persulfate solution were mixed and reacted at 50 °C for 6 h with stirring. After filtration, washing and drying, Ni was obtained. 0.98 Co 0.01 Mn 0.01 OOH.

[0072] This embodiment also provides a method for preparing a high-nickel cathode material, which is consistent with the method in Example 1.

[0073] Application Example 1-7 and Comparative Application Example 1-2 The high-nickel cathode material, acetylene black, and PVDF provided in Examples 1-7 and Comparative Examples 1-2 were dissolved in a certain amount of NMP at a mass ratio of 92:5:3 and mixed to form a slurry with a suitable viscosity (60% solid content). This slurry was coated onto aluminum foil and then vacuum dried and rolled to form a cathode electrode. Graphite, acetylene black, styrene-butadiene rubber, and carboxymethyl cellulose were dissolved in a certain amount of deionized water at a mass ratio of 95:2:2:1 and mixed to form a slurry with a suitable viscosity (50% solid content). This slurry was coated onto copper foil and then vacuum dried and rolled to form a cathode electrode. A 1.0 mol / L LiPF6 solution (with EC, DMC, and EMC in a volume ratio of 1:1:1) was used as the electrolyte. Button cells were assembled, corresponding to Application Examples 1-7 and Comparative Application Examples 1-5, respectively.

[0074] The batteries provided in corresponding use cases 1-7 and comparative application example 1-2 were subjected to electrochemical performance tests at room temperature and a voltage range of 2.5V-4.2V. The specific test results are shown in Table 1.

[0075] Table 1 The test results show that: (1) As can be seen from Application Examples 1-5, the preparation process of the present invention adds the oxidant solution in parallel with the reactants for co-precipitation reaction, which can achieve one-step preparation of a high-nickel hydroxyl oxide precursor rich in trivalent nickel with good structural stability. When used to prepare high-nickel cathode materials, it can reduce the charge-discharge volume strain of high-nickel cathode materials and improve long-cycle performance. Specifically, in Application Examples 1-5, the high-nickel ternary cathode material can achieve a cycle capacity retention rate of 97.43%-98.31% after 100 cycles at 4.25C, and in Application Examples 4-5, the high-nickel binary cathode material can achieve a cycle capacity retention rate of 93.30%-94.30% after 100 cycles at 4.25C.

[0076] (2) As can be seen from Application Example 1 and Application Examples 6-7, the present invention controls the concentration of oxidant in the reaction system during the coprecipitation reaction by adjusting the feed rate of the oxidant solution to 0.1L / h-1L / h, thereby achieving a better effect of complete oxidation of the surface and interior. If the feed rate is too low, the concentration of oxidant in the reaction system will be too low, the oxidation effect will be poor, and complete oxidation cannot be guaranteed. If the feed rate is too high, it will lead to waste of oxidant and increased cost.

[0077] (3) As can be seen from Application Example 1 and Comparative Application Example 1, compared with traditional Ni 0.98 Co 0.01 Mn 0.01 (OH)2 serves as a precursor for high-nickel cathode materials. The high-nickel hydroxyl oxide precursor rich in trivalent nickel provided by this invention has good structural stability. When used to prepare high-nickel cathode materials, it can reduce the volume strain of high-nickel cathode materials during charge and discharge, and effectively improve long-cycle performance.

[0078] (4) As can be seen from Application Example 1 and Comparative Application Example 2, the present invention uses a one-step co-precipitation method to prepare a high-nickel hydroxyl oxide precursor rich in trivalent nickel, which simplifies the production process, improves the preparation efficiency, is suitable for large-scale production, and can achieve more uniform oxidation of divalent nickel, making it easier to completely oxidize to trivalent nickel. Compared with the high-nickel precursor (Ni) rich in divalent nickel prepared first in Comparative Example 2, this method is more efficient. x M y This invention uses a two-step method to prepare the precursor by mixing it with an oxidant solution for oxidation. This avoids the phenomenon that only the surface of the precursor is oxidized to generate trivalent nickel while the internal oxidation is incomplete. This effectively improves the structural stability of the precursor and enhances the long-cycle performance of the high-nickel cathode material.

[0079] In summary, the preparation process of this invention involves adding the oxidant solution in parallel with the reactants for co-precipitation, which enables the one-step preparation of a high-nickel hydroxyl oxide precursor rich in trivalent nickel with good structural stability. When used to prepare high-nickel cathode materials, it can reduce the charge-discharge volume strain of the high-nickel cathode materials and improve long-cycle performance. In addition, the one-step co-precipitation method simplifies the production process, improves the preparation efficiency, and is suitable for large-scale production.

[0080] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a high-nickel hydroxyl oxide precursor, characterized in that, The preparation method includes the following steps: A mixed metal salt solution, precipitant solution, complexing agent solution and oxidant solution are added concurrently to the reaction substrate to carry out a co-precipitation reaction. Once the target median particle size D50 is reached, the feeding is stopped to obtain a high-nickel hydroxyl oxide precursor. The mixed metal salt solution includes a first metal element and a second metal element, wherein the first metal element is Ni and the second metal element includes Mn and / or Co.

2. The preparation method according to claim 1, characterized in that, The second metallic element includes Mn and Co; Preferably, the oxidant solution comprises sodium persulfate solution and / or hydrogen peroxide solution; Preferably, the concentration of the oxidant solution is 0.1 g / L to 2.5 g / L; Preferably, the feed rate of the oxidant solution is 0.1 L / h to 1 L / h.

3. The preparation method according to claim 1 or 2, characterized in that, The total mass concentration of metal elements in the mixed metal salt solution is 80 g / L-120 g / L; Preferably, the mass concentration of the precipitant solution is 10wt%-30wt%; Preferably, the mass concentration of the complexing agent solution is 10wt%-20wt%.

4. The preparation method according to any one of claims 1-3, characterized in that, The feed rate of the mixed metal salt solution is 1L / h-10L / h; Preferably, the feed rate of the precipitant solution is 1L / h-7L / h; Preferably, the feed rate of the complexing agent solution is 0.1 L / h to 1 L / h.

5. The preparation method according to any one of claims 1-4, characterized in that, The ammonia concentration in the reaction substrate is 0 g / L-10 g / L and is not 0; Preferably, the temperature of the reaction substrate is 20℃-80℃; Preferably, the pH of the reaction substrate is 8-12.

6. The preparation method according to any one of claims 1-5, characterized in that, The stirring rate for the coprecipitation reaction is 100 r / min-400 r / min; Preferably, the pH of the reaction system in the coprecipitation reaction is 8-12.5; Preferably, the ammonia concentration in the reaction system during the coprecipitation reaction is 0 g / L to 13 g / L and is not 0; Preferably, the temperature of the reaction system in the coprecipitation reaction is 20℃-80℃; Preferably, the concentration of the oxidant in the reaction system during the coprecipitation reaction is 0.3 g / L to 1 g / L; Preferably, the target median particle size D50 is 1μm-50μm.

7. A high-nickel hydroxyl oxide precursor, characterized in that, The high-nickel hydroxyl oxide precursor is prepared by the preparation method according to any one of claims 1-6, and the general chemical formula of the high-nickel hydroxyl oxide precursor is M. x N y OOH, where M is Ni, and N includes Mn and / or Co, x+y=1, 0.8≤x<1.

8. A high-nickel cathode material, characterized in that, The high-nickel cathode material is prepared using the high-nickel hydroxyl oxide precursor and lithium salt as described in claim 7.

9. A method for preparing a high-nickel cathode material according to claim 8, characterized in that, The preparation method includes the following steps: A high-nickel hydroxyl oxide precursor and a lithium salt are mixed evenly and then sintered to obtain a high-nickel cathode material.

10. A lithium-ion battery, characterized in that, The lithium-ion battery includes the high-nickel cathode material as described in claim 8, or the high-nickel cathode material prepared by the preparation method as described in claim 9.

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