Oxide precursor, preparation method therefor and use thereof

Abstract

An oxide precursor, a preparation method therefor and a use thereof. The oxide precursor has a general chemical formula of Ni xCo yMn zAl dM eO n, wherein 0＜x≤0.96, 0≤y≤0.96, 0≤z≤0.96, 0≤d≤0.15, 0＜e≤0.015, 0.6≤n≤1.6, x+y+z+d＝1, y, z and d are not simultaneously 0, and the metal element M has an ionic radius of ≥0.08 nm; and the distribution uniformity of the metal element M in the oxide precursor is greater than or equal to 98.5%. The oxide precursor has the uniformly distributed doping element M with a large ionic radius, which is conducive to improving the structural stability of a positive electrode material, such that a lithium ion battery has an excellent discharge capacity and cycle performance.

Description

Oxide precursor and its preparation method and application

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 20, 2023, with application number 202311756250.3 and application name “Oxide Precursor and Preparation Method and Application Thereof”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of lithium-ion batteries, and in particular to an oxide precursor and a preparation method and application thereof. Background Art

[0003] At present, the layered structure lithium ion cathode materials modified by doping have better performance and have attracted widespread attention. Traditional doping ions include Mg 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Ti 4+ etc., however, as Ba 2+ (ion radius is 0.135nm), Y 3+ (ion radius is 0.09nm), Ag + (ion radius is 0.115nm), Sr 2+ (ion radius is 0.118nm), Cs + (ion radius is 0.167nm), K + (ion radius is 0.138nm), Na + (ion radius is 0.102nm), In 3+ (with an ionic radius of 0.08nm) and other elements have large ions and are difficult to uniformly dope in the crystal phase. Furthermore, since the precursors used to prepare doped and modified cathode materials are agglomerated particles with a certain particle size (8μm-15μm), the diffusion path of the doping elements is long, making it easy for the concentration of the doping elements on the surface to be higher than that inside, or for local enrichment, which is not conducive to the doping elements fully exerting their modifying effect in the cathode material, thereby affecting the cycle performance of lithium-ion batteries. Summary of the Invention

[0004] Based on this, it is necessary to provide an oxide precursor and its preparation method and application to address the above problems; the oxide precursor has a uniformly distributed large ion radius doping element M, which is beneficial to improving the structural stability of the positive electrode material and enabling the lithium-ion battery to have excellent discharge capacity and cycle performance.

[0005] An oxide precursor, the chemical general formula of the oxide precursor being Ni x Co y Mn z Al d M e O n , where 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, d are not simultaneously 0, and the ionic radius of the metal element M ≥ 0.08 nm;

[0006] The uniformity of the distribution of the metal element M in the oxide precursor is greater than or equal to 98.5%.

[0007] In one embodiment, the D 50 of the oxide precursor ≤ 2 μm.

[0008] In one embodiment, the unit cell parameters of nickel oxide in the oxide precursor satisfy:

[0009] In one embodiment, in the X-ray diffraction pattern, the ratio of the diffraction peak intensity of the (012) crystal plane of the oxide precursor to the diffraction peak intensity of the (m1) crystal plane is 1:1 - 2:1.

[0010] In one embodiment, in the X-ray diffraction pattern, compared with the diffraction peak of the (012) crystal plane of standard nickel oxide, the diffraction peak of the (012) crystal plane of the oxide precursor shifts towards a smaller angle, and the shift amount is less than or equal to 3°.

[0011] In one embodiment, the metal element M is selected from at least one of Ba, Y, Ag, Sr, Cs, K, Na, In, Ce, Tl, Bi, Sc, Yb, Tm, Er, Te or Pd.

[0012] In one embodiment, the oxide precursor satisfies at least one of the following conditions:

[0013] (1) The loose bulk density of the oxide precursor ≥ 0.4 g / cm 3 ;

[0014] (2) The D 10 of the oxide precursor ≤ 0.5 μm;

[0015] (3) The D 90 [[ID=No. 51]]nbsp;of the oxide precursor ≤ 10 μm;

[0016] (4) The particle size distribution span value of the oxide precursor ≤ 5, and the particle size distribution span value is (D90 -D 10 ) / D 50 。

[0017] In one embodiment, the overall distribution uniformity of Ni, Co, Mn, and Al elements in the oxide precursor is greater than or equal to 98%.

[0018] The oxide precursor described in this application not only contains a large ionic radius doping element M with a specific ratio, but also has excellent doping uniformity. When used to prepare a cathode material, on the one hand, the main phase of the cathode material can be affected by the doping element M, making the crystal structure uniform and stable; on the other hand, the uniformly distributed doping element M can also make the stress distribution uniform, avoiding grain cracking caused by local stress concentration, thereby improving the cycle capacity retention rate and enabling the lithium-ion battery to have excellent discharge capacity and cycle performance.

[0019] ]>A method for preparing an oxide precursor as described above includes the following steps:

[0020] Taking Ni x Co y Mn z Al d M e O n , where 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, and d are not simultaneously 0 as a reference, preparing a mixed metal salt solution and performing a co-precipitation reaction with a precipitant solution to obtain a hydroxide, and the D 50 = 0.2 μm - 1 μm;

[0021] Sintering the hydroxide to obtain the oxide precursor.

[0022] In one embodiment, the co-precipitation reaction satisfies at least one of the following conditions:

[0023] (1) The molar ratio of metal ions in the mixed metal salt solution to hydroxide ions in the precipitant solution is 1:1 - 1:1.15;

[0024] (2) The total concentration of the mixed metal salt in the mixed metal salt solution is 0.5 mol / L - 3 mol / L;

[0025] (3) The concentration of the precipitant in the precipitant solution is 0.5 mol / L - 6 mol / L;

[0026] (4) The precipitant in the precipitant solution is selected from at least one of potassium hydroxide, sodium hydroxide, or lithium hydroxide;

[0027] (5) The temperature of the coprecipitation reaction is 25°C-45°C, and the time is 3h-10h.

[0028] In one embodiment, the step of sintering the hydroxide precipitate satisfies at least one of the following conditions:

[0029] (1) The volume of the hydroxide is 5%-35% of the volume of the sintering reaction space;

[0030] (2) the sintering is carried out in an oxygen-containing gas, the oxygen content of the oxygen-containing gas is greater than or equal to 21%, and the flow rate of the oxygen-containing gas is 1 L / min to 30 L / min;

[0031] (3) The sintering temperature is 350°C-650°C, and the sintering time is 1h-6h.

[0032] A positive electrode material is prepared from the oxide precursor as described above, wherein the distribution uniformity of the metal element M in the positive electrode material is greater than or equal to 98.5%.

[0033] In one embodiment, the molar amount of the metal element M is 0.01 mol%-1.5 mol% of the molar amount of other metal elements in the positive electrode material except Li and M elements.

[0034] A positive electrode sheet comprises the positive electrode material as described above.

[0035] A lithium-ion battery comprises the positive electrode sheet described above.

[0036] An electrical device comprises the lithium-ion battery described above.

[0037] The preparation method described in the present application does not use a complexing agent as in the traditional preparation method, but only adds a precipitant, so that a small-particle hydroxide uniformly doped with the element M is quickly generated during the co-precipitation reaction. Furthermore, during the sintering process of the hydroxide, the synergistic effect of the large ionic radius doping element M and the short diffusion path provided by the small particle size enables the doping element M to be uniformly diffused, further improving the effect of the uniform distribution of the doping element M, thereby obtaining an oxide precursor with a uniform distribution of the large ionic radius doping element M. This not only solves the problem that the traditional doping process is difficult to achieve uniform doping of elements with large ionic radius, but also the preparation process is simple, easy to operate, short in time, and highly efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 is a SEM cross-sectional view of the oxide precursor provided in Example 1;

[0040] Figure 2 is a SEM cross-sectional view of the oxide precursor provided in Comparative Example 1. Detailed implementation manners

[0041] To facilitate the understanding of the present application, the following will describe the present application in more detail. However, it should be understood that the present application can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure content of the present application more thorough and comprehensive.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments or examples and are not intended to limit this application. The optional range of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of the related listed items. The any and all combinations include any two related listed items, any more related listed items, or all related listed items.

[0043] The present application provides an oxide precursor, and the chemical general formula of the oxide precursor is Ni x Co y Mn z Al d M e O n , where 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, d are not simultaneously 0, and the ionic radius of the metal element M ≥ 0.08 nm.

[0044] At least 10 sample areas are selected from the oxide precursor, and the standard deviation σ1 is ≤ 1.5% of the mass of the metal element M in any sample area to the total mass of the elements. The distribution uniformity of the metal element M in the oxide precursor is defined as 1-σ1, that is, the distribution uniformity of the metal element M in the oxide precursor is greater than or equal to 98.5%.

[0045] It should be noted that Ni, Co, Mn, and Al are the main elements, and the metal element M is the doping element. The oxide precursor can be selected from a binary precursor whose main elements are Ni, Co or Ni, Mn or Ni, Al, a ternary precursor whose main elements are Ni, Co, Mn or Ni, Co, Al or Ni, Mn, Al, and a quaternary precursor whose main elements are Ni, Co, Mn, and Al.

[0046] The oxide precursor described in the present application not only contains a specific ratio of a doping element M with a large ionic radius, but also has excellent doping uniformity. When used to prepare a positive electrode material, on the one hand, the main phase of the positive electrode material can be affected by the doping element M, thereby uniformly stabilizing the crystal structure; on the other hand, the uniformly distributed doping element M can also make the stress distribution uniform, avoiding local stress concentration causing grain cracking, thereby improving the cycle capacity retention rate, and making the lithium-ion battery have excellent discharge capacity and cycle performance.

[0047] In one embodiment, the D of the oxide precursor 50 ≤2μm, where D 50 This refers to the particle size corresponding to the 50% cumulative particle size distribution percentage of the oxide precursor particles and can be used to represent the average particle size. Due to the small average particle size of the oxide precursor, it provides a shorter diffusion path for the dopant element M. Consequently, the synergistic effect of the large ionic radius dopant element M and the small particle size oxide precursor further improves the uniformity of the dopant element M distribution in the oxide precursor.

[0048] In one embodiment, the unit cell parameters of nickel oxide of the oxide precursor in XRD testing satisfy: Unit cell parameters of nickel oxide in R-3m space group relative to the standard PDF card (PDF#44-1159) The unit cell parameters a, b, and c of the oxide precursor are increased independently. It is beneficial to coordinately regulate the uniformity of the doping sites of the doping element M in the oxide precursor in the bulk phase, thereby further improving the uniformity of the doping sites of the doping element M in the positive electrode material, and further optimizing a, b, and c increase independently

[0049] In one embodiment, in the X-ray diffraction pattern, the ratio of the (012) crystal plane diffraction peak intensity to the (101) crystal plane diffraction peak intensity of the oxide precursor is 1:1-2:1, that is, I(012) / I(101)=1.0-2.0, so that the oxide precursor has a suitable degree of crystallinity, which is beneficial to improving the quality and performance of the positive electrode material.

[0050] In one embodiment, in the X-ray diffraction pattern, compared with the (012) crystal plane diffraction peak of standard nickel oxide, the (012) crystal plane diffraction peak of the oxide precursor shifts to a smaller angle, and the shift is less than or equal to 3°.

[0051] In one embodiment, the metal element M includes but is not limited to at least one of Ba, Y, Ag, Sr, Cs, K, Na, In, Ce, Tl, Bi, Sc, Yb, Tm, Er, Te or Pd.

[0052] In one embodiment, the oxide precursor satisfies at least one of the following conditions:

[0053] (1) The bulk density of the oxide precursor is ≥0.4 g / cm 3 ;

[0054] (2) D of the oxide precursor 10 ≤0.5μm;

[0055] (3) D of the oxide precursor 90 ≤10μm;

[0056] (4) The particle size distribution span value of the oxide precursor is ≤5, and the particle size distribution span value is (D 90 -D 10 ) / D 50 .

[0057] By regulating the particle size distribution of the oxide precursor, the doping element M can be more easily diffused into the bulk phase of the positive electrode material. At the same time, controlling the oxide precursor to have a more reasonable bulk density so that the unit mass of the oxide precursor has an appropriate volume is more conducive to improving the processing performance of the positive electrode material.

[0058] Among them, D 10 It refers to the particle size corresponding to when the cumulative particle size distribution percentage of the oxide precursor particles reaches 10%; D 90 It refers to the particle size corresponding to when the cumulative particle size distribution percentage of the oxide precursor particles reaches 90%.

[0059] In one embodiment, at least 10 sample regions are selected in the oxide precursor. Taking the percentage of the sum of the masses of Ni, Co, Mn, and Al elements in any sample region accounting for the total mass of the elements, the standard deviation σ2 ≤ 2%. The overall distribution uniformity of Ni, Co, Mn, and Al elements in the oxide precursor is defined as 1 - σ2, that is, the overall distribution uniformity of Ni, Co, Mn, and Al elements in the oxide precursor is greater than or equal to 98%.

[0060] Traditional precursor doping modification mainly includes two routes. One is to uniformly mix an additive containing doping elements with a precursor synthesized by the co-precipitation method and a lithium source before producing the cathode material by the high-temperature solid-phase method, and then calcine. Since the precursor itself is an agglomerated particle with a certain particle size (8μm - 15μm), during the reaction stage, the doping elements diffuse into the bulk phase of the cathode material, with a long diffusion path, making it difficult to achieve uniform doping. Moreover, due to simple mechanical mixing, the doping elements are difficult to achieve uniform distribution in the precursor, and it is also difficult to achieve uniform doping. The other is to adjust various condition parameters during the preparation of the co-precipitation precursor to allow the doping elements to be doped into the co-precipitation precursor. Since there are many condition parameters to be adjusted and they affect each other, it is difficult to produce a consistent doped precursor. And this scheme requires re-adjustment when switching doping elements and processes, which is not universal and greatly increases the production difficulty.

[0061] Based on this, the present application provides a method for preparing the above-mentioned oxide precursor, including the following steps:

[0062] S1, taking Ni x Co y Mn z Al d M e O n , with 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, d are not all 0 as a reference, prepare a mixed metal salt solution and carry out a co-precipitation reaction with a precipitant solution to obtain a hydroxide, and the D 50 of the hydroxide is 0.2μm - 1μm;

[0063] S2, sinter the hydroxide to obtain the oxide precursor.

[0064] In step S1, without using a complexing agent in the traditional preparation method, by only adding a precipitant, specific small-sized hydroxide is rapidly generated during the co-precipitation reaction, which is beneficial to ensuring the uniformity of each element, especially enabling uniform doping of the metal element M. <00003@9>In one embodiment, the coprecipitation reaction satisfies at least one of the following conditions:

[0066] (1) the molar ratio of the metal ions in the mixed metal salt solution to the hydroxide ions in the precipitant solution is 1:1-1:1.15;

[0067] (2) the total concentration of the mixed metal salt in the mixed metal salt solution is 0.5 mol / L-3 mol / L;

[0068] (3) The concentration of the precipitant in the precipitant solution is 0.5 mol / L-6 mol / L;

[0069] (4) the precipitant in the precipitant solution is selected from at least one of potassium hydroxide, sodium hydroxide, or lithium hydroxide;

[0070] (5) The temperature of the coprecipitation reaction is 25°C-45°C, and the time is 3h-10h.

[0071] The temperature and time of the co-precipitation reaction in the preparation method described in the present application are shorter and the conditions are milder. While ensuring that the hydroxide has a certain particle size, the processing cost can be reduced and the uniformity of each element can be guaranteed.

[0072] In one embodiment, the specific method of the co-precipitation reaction is preferably: the mixed metal salt solution and the precipitant solution are fed into the reaction device in parallel.

[0073] It is understandable that after the coprecipitation reaction is completed, conventional treatment methods such as aging, washing, and drying are also included, and this application does not limit this.

[0074] In step S2, during the sintering process of the hydroxide, the doping element M is diffused evenly through the synergistic effect of the large ionic radius doping element M and the small particle size providing a short diffusion path, further improving the effect of the uniform distribution of the doping element M, thereby obtaining an oxide precursor with a uniform distribution of the large ionic radius doping element M.

[0075] In one embodiment, the step of sintering the hydroxide precipitate satisfies at least one of the following conditions:

[0076] (1) The volume of the hydroxide is 5%-35% of the volume of the sintering reaction space;

[0077] (2) the sintering is carried out in an oxygen-containing gas, the oxygen content of the oxygen-containing gas is greater than or equal to 21%, and the flow rate of the oxygen-containing gas is 1 L / min to 30 L / min;

[0078] (3) The sintering temperature is 350°C-650°C, and the sintering time is 1h-6h.

[0079] The ratio of the volume of the hydroxide to the volume of the sintering reaction space is the filling rate of the reaction material.

[0080] By regulating the sintering temperature, time, filling rate of the reaction materials, reaction gas and flow rate, not only can the uniform diffusion of the doping element M be ensured, but also the oxide precursor can have a certain particle size distribution, loose density and crystallinity. In addition, the sintering cost can be reduced, which is conducive to industrial production.

[0081] It is understood that the specific process of the preparation method described in this application includes but is not limited to batch process and continuous process, and this application does not impose any restrictions on this.

[0082] Therefore, the preparation method described in the present application not only solves the problem that traditional doping processes are difficult to achieve uniform doping of elements with large ion radius, but also the preparation process is simple, easy to operate, time-saving and efficient.

[0083] The present application provides a positive electrode material, which is made from the oxide precursor as described above. At least 10 sample areas are selected from the positive electrode material. The standard deviation σ3 is ≤ 1.5%, calculated as the percentage of the mass of the metal element M in any sample area to the total mass of the element. The distribution uniformity of the metal element M in the positive electrode material is defined as 1-σ3, that is, the distribution uniformity of the metal element M in the positive electrode material is greater than or equal to 98.5%.

[0084] The positive electrode material described in this application not only has a uniform and stable crystal structure, but also has a uniform stress distribution inside the material. It is not easy to produce adverse phenomena such as grain cracking during the charge and discharge process, which is beneficial to improving the cycle capacity retention rate and making the lithium-ion battery have excellent discharge capacity and cycle performance.

[0085] It should be noted that the metal element M can occupy the lithium ion site, the transition metal ion site, or both sites at the same time during the doping process to form a mixed doping site, which is not limited in this application.

[0086] In one embodiment, the molar amount of the metal element M is 0.01 mol% to 1.5 mol% of the molar amount of other metal elements in the positive electrode material except Li and M elements.

[0087] It should be noted that the present application does not limit the preparation method of the positive electrode material, and it can be prepared by conventional processes. For example, the oxide precursor described in the present application and the lithium source are fully mixed in a molar ratio of 1: (1-1.5) to obtain a mixture, and then the mixture is calcined at a high temperature of 650°C-1000°C under an oxygen or air atmosphere to obtain a positive electrode material, wherein the trace loss of the metal element M during the preparation process is supplemented, and an additive containing the metal element M can be added to the mixture. The molar ratio of the oxide precursor to the additive containing the metal element M is 1: (0.0001-0.05).

[0088] The present application provides a positive electrode sheet, comprising the positive electrode material as described above.

[0089] Specifically, the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the positive electrode material described in this application.

[0090] In one embodiment, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector includes a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material on a polymer material substrate. Optionally, the metal material includes but is not limited to one or more of aluminum, aluminum gold, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. Optionally, the polymer material substrate includes but is not limited to one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0091] In one embodiment, the positive electrode film layer is primarily composed of the positive electrode material described herein, a binder, and a conductive agent. Optionally, the conductive agent includes, but is not limited to, at least one of carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, wherein the carbon black includes superconducting carbon, acetylene black, or Ketjen black.

[0092] It should be noted that this application does not limit the preparation method of the positive electrode sheet, and conventional processes can be used for preparation. For example, the positive electrode material, conductive agent, binder, and any other components are dispersed in a solvent to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing, and other processes, the positive electrode sheet can be obtained. Optionally, the solvent includes but is not limited to N-methylpyrrolidone.

[0093] The present application provides a lithium-ion battery, comprising the positive electrode sheet as described above.

[0094] The lithium-ion battery is mainly composed of a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the negative electrode sheet, the separator and the electrolyte can adopt any conventional commercially available negative electrode sheet (or negative electrode material), the separator and the electrolyte, and this application does not impose any limitation on this.

[0095] The present application also provides an electrical device comprising the lithium-ion battery described above.

[0096] It is understandable that the above-mentioned power consumption settings include any equipment that uses the above-mentioned lithium-ion batteries, such as electric vehicles, power tools, electronic products, energy storage systems, and office equipment, but are not limited thereto.

[0097] The oxide precursor, its preparation method, and application will be further described below through the following specific examples. However, those skilled in the art will understand that the following examples are only for illustration purposes and should not be considered as limiting the scope of this application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used, for which the manufacturer is not specified, are all commercially available conventional products.

[0098] Example 1

[0099] The acetates of nickel, cobalt, manganese and strontium chloride were prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Sr=8:1:1:0.01, and were simultaneously flowed into a reactor with a 10 mol / L sodium hydroxide aqueous solution, and a co-precipitation reaction was carried out at a constant temperature of 25°C with stirring for 8 hours. The hydroxide precipitate produced by the reaction was filtered, washed, dried and sieved, and then loaded into a sagger, and placed in an atmosphere furnace for sintering. The reaction gas was pure oxygen gas with a flow rate of 5 L / min, the filling rate of hydroxide in the furnace was 20%, and the sintering condition was kept at 350°C for 6 hours. Finally, a strontium-doped oxide precursor with a nickel-cobalt-manganese molar ratio of 8:1:1 was obtained. The chemical formula of the oxide precursor was Ni 0.8 Co 0.1 Mn 0.1 Sr 0.001 O 1.001 .

[0100] The oxide precursor prepared in this example was thoroughly mixed with lithium hydroxide monohydrate in a high-speed mixer at 500 rpm for 30 minutes at a molar ratio of the main element metal to the molar ratio of lithium of 1:1.01 to obtain a mixture. The mixture was then calcined in an oxygen atmosphere box furnace at 800°C for 16 hours, then naturally cooled to room temperature, crushed, and sieved to obtain a positive electrode material.

[0101] Example 2

[0102] The difference between Example 2 and Example 1 is that the acetates of nickel, cobalt, and manganese and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Sr=8:1:1:0.02.

[0103] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 1.002 .

[0104] Example 3

[0105] The difference between Example 3 and Example 1 is that the acetates of nickel, cobalt, and manganese and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Sr=8:1:1:0.05.

[0106] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.005 O 1.005 .

[0107] Example 4

[0108] The difference between Example 4 and Example 1 is that the acetates of nickel, cobalt, and manganese and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Sr=6:1:3:0.02.

[0109] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.6 Co 0.1 Mn 0.3 Sr 0.002 O 1.002 .

[0110] Example 5

[0111] The difference between Example 5 and Example 1 is that the acetates of nickel, cobalt, aluminum and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Al:Sr=8:1:1:0.02.

[0112] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Al 0.1 Sr 0.002 O 1.002 .

[0113] Example 6

[0114] The difference between Example 6 and Example 1 is that the acetates of nickel, cobalt, and manganese and yttrium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Y=8:1:1:0.02.

[0115] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Y 0.002 O 1.003 .

[0116] Example 7

[0117] The difference between Example 7 and Example 1 is that the acetates of nickel, cobalt, and manganese and barium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Ba=8:1:1:0.02.

[0118] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Ba 0.002 O 1.002 .

[0119] Example 8

[0120] The difference between Example 8 and Example 1 is that the acetates of nickel, cobalt, and manganese and cerium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Ce=8:1:1:0.02.

[0121] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Ce 0.002 O 1.004 .

[0122] Example 9

[0123] The difference between Example 9 and Example 2 is that the temperature of the coprecipitation reaction is 35°C.

[0124] Example 10

[0125] The difference between Example 10 and Example 2 is that the temperature of the coprecipitation reaction is 45°C.

[0126] Example 11

[0127] The difference between Example 11 and Example 2 is that the coprecipitation reaction time is 3 hours.

[0128] Example 12

[0129] The difference between Example 12 and Example 2 is that the coprecipitation reaction time is 5 hours.

[0130] Example 13

[0131] The difference between Example 13 and Example 2 is that the coprecipitation reaction time is 10 hours.

[0132] Example 14

[0133] The difference between Example 14 and Example 2 is that the sintering temperature is 250°C.

[0134] Example 15

[0135] The difference between Example 15 and Example 2 is that the sintering temperature is 550°C.

[0136] Example 16

[0137] The difference between Example 16 and Example 2 is that the sintering time is 2 hours.

[0138] Example 17

[0139] The difference between Example 17 and Example 2 is that the sintering time is 4 hours.

[0140] Example 18

[0141] The difference between Example 18 and Example 2 is that the sintering time is 8 hours.

[0142] Example 19

[0143] The difference between Example 19 and Example 2 is that the sintering reaction gas is air with an oxygen content of 21%.

[0144] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn0.1 Sr 0.002 O 0.6 .

[0145] Example 20

[0146] The difference between Example 20 and Example 2 is that the sintering reaction gas is air with an oxygen content of 50%.

[0147] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 0.8 .

[0148] Example 21

[0149] The difference between Example 21 and Example 2 is that the flow rate of pure oxygen is 1 L / min.

[0150] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 0.9 .

[0151] Example 22

[0152] The difference between Example 22 and Example 2 is that the flow rate of pure oxygen is 30 L / min.

[0153] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 1.6 .

[0154] Example 23

[0155] The difference between Example 23 and Example 2 is that the filling rate of hydroxide in the furnace is 5%.

[0156] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 0.95 .

[0157] Example 24

[0158] The difference between Example 24 and Example 2 is that the filling rate of hydroxide in the furnace is 35%.

[0159] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.002 O 1.2 .

[0160] Example 25

[0161] The difference between Example 25 and Example 1 is that the acetates of nickel and cobalt and potassium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:K=0.04:0.96:0.015.

[0162] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.04 Co 0.96 K 0.015 O 1.0075 .

[0163] Example 26

[0164] The difference between Example 26 and Example 1 is that the acetates of nickel and manganese and cesium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Mn:Cs=0.04:0.96:0.015.

[0165] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.04 Mn 0.96 Cs 0.015 O 1.0075 .

[0166] Example 27

[0167] The difference between Example 27 and Example 1 is that the acetates of nickel, manganese, aluminum and rubidium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Mn:Al:Rb=0.5:0.35:0.15:0.01.

[0168] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.5 Mn 0.35Al 0.15 Rb 0.01 O 1.005 .

[0169] Example 28

[0170] The difference between Example 28 and Example 1 is that the acetates of nickel, cobalt, manganese, aluminum and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Al:Sr=0.96:0.02:0.01:0.01:0.001.

[0171] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.96 Co 0.02 Mn 0.01 Al 0.01 Sr 0.001 O 1.001 .

[0172] Comparative Example 1

[0173] A mixed salt solution of Ni, Co, and Mn was prepared in a molar ratio of 8:1:1 to obtain solution A with a concentration of 2 mol / L; a mixed salt solution of Ni, Co, Mn, and Sr was prepared in a molar ratio of 8:1:1:0.02 to obtain solution B with a concentration of 2 mol / L; solution A, an ammonia complexing agent, and a sodium hydroxide precipitant were simultaneously flowed into a reactor, and the pH value of the reaction process was controlled under heating and stirring conditions to co-precipitate to generate a precursor C; solution B, an ammonia complexing agent, and a sodium hydroxide precipitant were then simultaneously flowed into the reactor, and the pH value of the reaction process was controlled under heating and stirring conditions to allow the precursor C particles to continue to grow. After reaching the target particle size, a strontium-doped oxide precursor was obtained by filtration, washing, drying, and sieving. The chemical formula of the oxide precursor was Ni(III) as tested by inductively coupled plasma optical emission spectrometry (ICP-OES / AES). 0.8 Co 0.1 Mn 0.1 Sr 0.001 O 1.002 .

[0174] The oxide precursor prepared in this comparative example was thoroughly mixed with lithium hydroxide monohydrate in a high-speed mixer at 500 rpm for 30 minutes at a molar ratio of the main element metal to lithium of 1:1.01 to produce a mixture. The mixture was then calcined in an oxygen atmosphere box furnace at 800°C for 16 hours, then naturally cooled to room temperature. The mixture was crushed and sieved to produce a positive electrode material.

[0175] Comparative Example 2

[0176] A mixed salt solution of Ni, Co, and Mn was prepared in a molar ratio of 8:1:1 to obtain solution A with a concentration of 2 mol / L; part of solution A, an ammonia complexing agent, and sodium hydroxide were simultaneously flowed into a reactor, and the pH value of the reaction process was controlled under heating and stirring conditions to co-precipitate to generate a precursor C; the remaining solution A, an ammonia complexing agent, and a sodium hydroxide precipitant were simultaneously flowed into a reactor, and the pH value of the reaction process was controlled under heating and stirring conditions. The precursor C particles continued to grow, and after reaching the target particle size, they were filtered, washed, dried, and sieved to obtain a ternary oxide precursor. The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor was Ni 0.8 Co 0.1 Mn 0.1 O1.

[0177] The oxide precursor prepared in the comparative example, lithium hydroxide monohydrate, and strontium chloride were thoroughly mixed in a high-speed mixer at 500 rpm for 30 minutes at a molar ratio of 1:1.01:0.001 to obtain a mixture. The mixture was calcined in an oxygen atmosphere box furnace at 800°C for 16 hours, then naturally cooled to room temperature. The mixture was crushed and sieved to obtain a positive electrode material.

[0178] Comparative Example 3

[0179] The difference between Comparative Example 3 and Example 1 is that the acetates of nickel, manganese, aluminum and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Mn:Al:Sr=7:1:2:0.01.

[0180] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.7 Mn 0.1 Al 0.2 Sr 0.001 O 1.001 .

[0181] Comparative Example 4

[0182] The difference between Comparative Example 4 and Example 1 is that the acetates of nickel, cobalt, and manganese and strontium chloride are prepared into an aqueous solution with a total element concentration of 2 mol / L according to the metal element molar ratio of Ni:Co:Mn:Sr=8:1:1:0.2.

[0183] The inductively coupled plasma optical emission spectrometer (ICP-OES / AES) test showed that the chemical formula of the oxide precursor is Ni 0.8 Co 0.1 Mn 0.1 Sr 0.02 O1.02 .

[0184] The oxide precursors prepared in Examples 1 to 28 and Comparative Examples 1 to 4 were tested, and the results are shown in Figures 1 to 2 and Tables 1 to 3.

[0185] Table 1

[0186] Table 2

[0187] Table 3

[0188] The positive electrode materials prepared in Examples 1 to 28 and Comparative Examples 1 to 4 were tested, and the results are shown in Table 4.

[0189] Table 4

[0190] Application Examples

[0191] The positive electrode materials prepared in Examples 1 to 28 and Comparative Examples 1 to 4 were used to prepare button-type half-cells, respectively. The button-type half-cells were prepared by the following steps:

[0192] Conductive carbon black SP (particle size 40nm): PVDF (molecular weight 900,000) = 90%: 5%: 5% were dissolved in n-methyl-1,2-pyrrolidone solvent (NMP) and placed in a dry room (dew point temperature -45℃, room size 15m 2 ) to obtain a uniform positive electrode slurry, and the cathode slurry was coated on an aluminum foil current collector (thickness of 12 μm, purity of 99.5%), which was cut into a flat plate with a diameter of 12 mm to form a mass loading of 8.5 ± 0.15 mg / cm 2 The positive electrode sheet was prepared using an 11 mm diameter lithium metal disc (0.3 mm thickness, 99.9% purity) as the counter electrode and 1 mol / L LiPF6 ethyl carbonate / diethylene carbonate (EC / DEC, 1:1 by volume, H2O <10 ppm) as the electrolyte. The battery was assembled in an argon-filled glove box (water and oxygen contents were both less than 0.1 ppm) to form a 2032-type button-type half-cell.

[0193] The assembled battery was subjected to the following performance tests, and the test results are shown in Table 5.

[0194] (1) Cycle performance test: The battery is charged at 1C and discharged at 1C. The battery is charged and discharged in a cycle at a cut-off current of 0.05C and an ambient temperature of 25℃±2℃. The voltage range is 2.8V-4.25V. The capacity retention rate of the battery is calculated after 100 cycles. The capacity retention rate is the ratio of the discharge capacity in the 100th week to the discharge capacity in the first week.

[0195] (2) Discharge capacity: Charge and discharge test is performed at 0.2C, and the test voltage range is 2.8V-4.25V.

[0196] Table 5

[0197] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0198] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An oxide precursor, wherein: The chemical general formula of the oxide precursor is Ni x Co y Mn z Al d M e O n , where 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, d are not simultaneously 0, and the ionic radius of the metal element M ≥ 0.08 nm; The distribution uniformity of the metal element M in the oxide precursor is greater than or equal to 98.5%.

2. The oxide precursor according to claim 1, wherein The oxide precursor D 50 ≤2μm.

3. The oxide precursor according to claim 1, wherein The unit cell parameters of nickel oxide in the oxide precursor satisfy:

4. The oxide precursor according to claim 1, wherein In the X-ray diffraction spectrum, the ratio of the diffraction peak intensity of the (012) crystal plane of the oxide precursor to the diffraction peak intensity of the (101) crystal plane is 1:1-2:

1.

5. The oxide precursor according to claim 1, wherein In the X-ray diffraction spectrum, compared with the (012) crystal plane diffraction peak of standard nickel oxide, the (012) crystal plane diffraction peak of the oxide precursor shifts to a smaller angle, and the shift amount is less than or equal to 3°.

6. The oxide precursor according to claim 1, wherein The metal element M is selected from at least one of Ca, Sn, Cd, Ba, Y, Ag, Sr, Cs, K, Na, In, Ce, Tl, Bi, Sc, Yb, Tm, Er, Te and Pd.

7. The oxide precursor according to claim 1, wherein The oxide precursor satisfies at least one of the following conditions: (1) The bulk density of the oxide precursor is ≥ 0.4 g / cm 3 ; (2) D of the oxide precursor 10 ≤0.5μm; (3) D of the oxide precursor 90 ≤10μm; (4) The particle size distribution span of the oxide precursor is ≤5, and the particle size distribution span is (D 90 -D 10 ) / D 50 .

8. The oxide precursor according to claim 1, wherein The overall distribution uniformity of Ni, Co, Mn and Al elements in the oxide precursor is greater than or equal to 98%.

9. A method for preparing an oxide precursor according to any one of claims 1 to 8, wherein: The steps include: Based on Ni x Co y Mn z Al d M e O n ,with 0 < x ≤ 0.96, 0 ≤ y ≤ 0.96, 0 ≤ z ≤ 0.96, 0 ≤ d ≤ 0.15, 0 < e ≤ 0.015, 0.6 ≤ n ≤ 1.6, x + y + z + d = 1, and y, z, d not being 0 simultaneously as the reference, prepare a mixed metal salt solution and carry out a coprecipitation reaction with a precipitant solution to obtain a hydroxide, and the D 50 = 0.2 μm - 1 μm; The hydroxide is sintered to obtain the oxide precursor.

10. The method for preparing an oxide precursor according to claim 9, wherein: The coprecipitation reaction satisfies at least one of the following conditions: (1) The molar ratio of the metal ions in the mixed metal salt solution to the hydroxide ions in the precipitant solution is 1:1-1:1.15; (2) The total concentration of the mixed metal salt in the mixed metal salt solution is 0.5 mol / L-3 mol / L; (3) The concentration of the precipitant in the precipitant solution is 0.5 mol / L-6 mol / L; (4) the precipitant in the precipitant solution is selected from at least one of potassium hydroxide, sodium hydroxide or lithium hydroxide; (5) The coprecipitation reaction is carried out at a temperature of 25°C-45°C and for a time of 3h-10h.

11. The method for preparing an oxide precursor according to claim 9, wherein: The step of sintering the hydroxide precipitate satisfies at least one of the following conditions: (1) The volume of the hydroxide is 5%-35% of the volume of the sintering reaction space; (2) the sintering is carried out in an oxygen-containing gas, the oxygen content of the oxygen-containing gas is greater than or equal to 21%, and the flow rate of the oxygen-containing gas is 1 L / min-30 L / min; (3) The sintering temperature is 350°C-650°C and the sintering time is 1h-6h.

12. A positive electrode material, wherein: Made from the oxide precursor according to any one of claims 1 to 8, the distribution uniformity of the metal element M in the positive electrode material is greater than or equal to 98.5%.

13. The positive electrode material according to claim 12, wherein The molar amount of the metal element M is 0.01 mol% to 1.5 mol% of the molar amount of other metal elements in the positive electrode material except Li and M elements.

14. A positive electrode sheet, wherein: Includes the positive electrode material according to claim 12 or claim 13.

15. A lithium ion battery, wherein: Comprising the positive electrode sheet as claimed in claim 14.

16. An electrical device, wherein: Comprising the lithium ion battery as claimed in claim 15.

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