Positive electrode precursor having narrow particle size distribution, and preparation method therefor and use thereof

Abstract

Disclosed herein are a positive electrode precursor having a narrow particle size distribution, and a preparation method therefor and a use thereof. The chemical general formula of the positive electrode precursor is NiaCobMncRz, wherein R comprises hydroxide and / or carbonate, 0<a≤1, 0≤b<1, 0≤c<1, a+b+c=1, 1≤z≤2, and (D90-D10) / D50 of the positive electrode precursor is less than 0.8. (D90-D10) / D50 of the positive electrode precursor material provided by the present application is less than 0.8; the nickel-cobalt-manganese elements have uniform distribution, concentrated particle size distribution, high sphericity, uniform particle appearance, stable structure, and high tap density, so that the obtained positive electrode material has stable structure, uniform particle, and good electrochemical performance.

Description

A positive electrode precursor with narrow particle size distribution and its preparation method and application Technical Field

[0001] The embodiments of the present application relate to the technical field of lithium-ion batteries, such as a positive electrode precursor with a narrow particle size distribution, a preparation method thereof, and an application thereof. Background Art

[0002] As a new type of green secondary battery, lithium-ion power batteries offer advantages such as high operating voltage, compact size, light weight, high energy, and relatively low toxicity. They are widely used in portable electronic devices such as mobile phones, laptops, compact video cameras, and digital cameras, and are also expanding into electric vehicles, satellites, and aerospace. Cathode materials are a key factor limiting the development of high-energy and high-density lithium-ion batteries, but their high cost is a major factor. Ternary materials are considered one of the most promising cathode materials due to their high energy density, relatively low cost, and excellent cycling performance.

[0003] Related technologies for preparing nickel-cobalt-manganese hydroxide generally employ direct precipitation, spray drying, or coprecipitation using a complexing agent and surfactant. The direct precipitation method involves a direct reaction of a nickel-cobalt-manganese soluble salt solution with an aqueous sodium hydroxide solution to produce a fine, flocculent nickel-cobalt-manganese hydroxide precipitate. This product, after filter pressing, washing, drying, and crushing, is then obtained. This process produces a product with uneven distribution of the three elements nickel, cobalt, and manganese, resulting in uneven particle size, poor particle morphology, and low tap density. While the spray drying method can produce a hydroxide precipitate with a uniform distribution of nickel, cobalt, and manganese, the particles still have poor morphology, low tap density, and difficulty controlling various physical properties. The coprecipitation method using a complexing agent and surfactant involves a controlled precipitation reaction between a nickel-cobalt-manganese soluble salt solution and an aqueous sodium hydroxide solution under the combined action of a complexing agent and surfactant. This method produces a product with a uniform distribution of nickel, cobalt, and manganese elements, uniform particle size, and controllable particle size, resulting in a spherical particle shape. However, the particle surface remains loose, the tap density is relatively low, and, due to the surfactant, the carbon content in the precursor is high.

[0004] Therefore, how to obtain a hydroxide precursor material with concentrated particle size distribution, uniform particle morphology, stable structure and high tap density is a technical problem that needs to be solved urgently.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The embodiments of the present application provide a cathode precursor with a narrow particle size distribution, its preparation method and application. The cathode precursor material provided by the present application has a (D90 - D10) / D50 less than 0.8. The nickel, cobalt and manganese elements are evenly distributed, the particle size distribution is concentrated, the sphericity is high, the particle morphology is uniform, the structure is stable and the tap density is relatively high, so that the obtained cathode material has a stable structure, uniform particles and good electrochemical performance.

[0008] In the first aspect, the embodiments of the present application provide a cathode precursor with a narrow particle size distribution. The chemical general formula of the cathode precursor is Ni a Co b Mn c R z , where R includes hydroxide and / or carbonate, 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2;

[0009] The (D90 - D10) / D50 of the cathode precursor is less than 0.8.

[0010] For example, a can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.; b can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, etc.; c can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, etc.; z can be 1, 1.5 or 2, etc.

[0011] The distance (D90 - D10) / D50 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.75, etc.

[0012] For the cathode precursor material provided by the present application, within the range where (D90 - D10) / D50 is less than 0.8, the nickel, cobalt and manganese elements are evenly distributed, the particle size distribution is concentrated, the sphericity is high, the particle morphology is uniform, the structure is stable and the tap density is relatively high, so that the obtained cathode material has a stable structure, uniform particles and good electrochemical performance.

[0013] Preferably, 0.3 ≤ (D90 - D10) / D50 ≤ 0.5, such as 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48 or 0.5, etc.

[0014] In the present application, when the distance is further within the range of 0.3 - 0.5, the particle size distribution in the cathode precursor is more concentrated, the sphericity is higher, it has a highly uniform particle morphology, and the particles are compact and not loose, with a high tap density and a more stable structure.

[0015] Preferably, the cathode precursor with a narrow particle size distribution further includes a doping element.

[0016] Preferably, the D50 of the cathode precursor with a narrow particle size distribution is 1-20 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, etc.

[0017] In a second aspect, an embodiment of the present application provides a method for preparing a cathode precursor with a narrow particle size distribution as described in the first aspect. The preparation method includes the following steps:

[0018] The main metal element mixed salt solution, the precipitant solution and the complexing agent solution are added to the bottom liquid in a co-current manner to carry out a coprecipitation reaction to obtain the cathode precursor with a narrow particle size distribution;

[0019] Among them, the main metal element in the main metal element mixed salt solution is the same as the metal element in a [ Co b [ Mn c [ R z [ where 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2.

[0020] The preparation method provided by the present application is simple to operate, and the particle size of the particles is controllable, which is suitable for large-scale production.

[0021] Preferably, the mass concentration of the main metal element mixed salt solution is 80-120 g / L, such as 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, etc.

[0022] In the present application, the main metal element mixed salt solution includes but is not limited to at least one of a sulfate solution, a chloride solution or a nitrate solution.

[0023] Preferably, the precipitant solution includes a liquid alkali solution and / or a sodium carbonate solution.

[0024] Preferably, the mass concentration of the liquid alkali solution is 10-30%, such as 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28% or 30%, etc.

[0025] Preferably, the molar concentration of the sodium carbonate solution is 1-10 mol / L, such as 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L or 10 mol / L, etc.

[0026] Preferably, the complexing agent solution comprises an aqueous ammonia solution.

[0027] Preferably, the mass concentration of the ammonia solution is 10-20%, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc.

[0028] Preferably, the solution added in parallel further comprises a dopant solution.

[0029] Preferably, the pH value of the base solution is 8-13, for example, 8, 8.3, 8.5, 8.8, 9, 9.3, 9.5, 9.8, 10, 10.3, 10.5, 10.8, 11, 11.3, 11.5, 11.8, 12, 12.3, 12.5, 12.8 or 13.

[0030] Preferably, the mass concentration of the complexing agent in the base solution is 0-120 g / L, for example, 0 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L.

[0031] Preferably, the pH value during the coprecipitation reaction is 8-13, for example, 8, 8.3, 8.5, 8.8, 9, 9.3, 9.5, 9.8, 10, 10.3, 10.5, 10.8, 11, 11.3, 11.5, 11.8, 12, 12.3, 12.5, 12.8 or 13.

[0032] Preferably, the reaction temperature during the coprecipitation reaction is 20-80°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C.

[0033] Preferably, the reaction speed during the coprecipitation reaction is 100-400 r / min, for example, 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min or 400 r / min.

[0034] In the present application, by regulating and coordinating various parameters in the above-mentioned coprecipitation reaction process, positive electrode precursor particles with a relatively concentrated particle size distribution can be obtained.

[0035] Preferably, the reaction time of the coprecipitation reaction is 100 to 150 h, for example, 100 h, 105 h, 110 h, 115 h, 120 h, 125 h, 130 h, 135 h, 140 h, 145 h or 150 h.

[0036] In this application, by extending the reaction time of the co-precipitation reaction, the particle size concentration of the particles can be further improved. After ≥100h, the particles will grow slowly, the sphericity will gradually improve, and the tap density will increase; if the reaction time is less than 100h, the sphericity of the particles is poor, the multi-head phenomenon is serious, and the tap density is small, which affects the later sintering of the positive electrode.

[0037] Preferably, the coprecipitation reaction comprises a bushing reaction.

[0038] In the present application, the concentration of particles can be better improved by prolonging the coprecipitation reaction time during the dense reaction process.

[0039] Preferably, the concentrated reaction is carried out in a reactor equipped with a concentrator.

[0040] In the present application, the concentration reaction is carried out directly in a reactor equipped with a concentrator, and the transfer process of the reaction liquid is omitted, thereby avoiding the inconsistent particle growth that may be caused by long pipeline transportation, and some secondary particles remain in the concentrator of the pipeline and cannot grow; and the concentration reaction increases the solid content of the particles in the reactor, slows down the growth rate of the particles, and improves the sphericity and tap density of the particles.

[0041] The specific operation process of the thickening reaction is as follows: when the liquid level in the reactor reaches a certain height, the thickener switch automatically opens. Under the action of the pressure in the reactor, the liquid is discharged and the solids are trapped. When the liquid level drops to a certain position, the thickener switch automatically closes.

[0042] Preferably, the coprecipitation reaction is carried out in a micro-oxygen atmosphere.

[0043] In the present application, the coprecipitation reaction is carried out in a micro-oxygen atmosphere, and the particles are micro-oxidized, which is beneficial to reduce the agglomeration of the secondary particles in the early stage, thereby significantly improving the sphericity of the precursor and increasing the tap density, thereby achieving a concentrated distribution of particle size.

[0044] Furthermore, the micro-oxygen atmosphere is a mixed gas containing oxygen (for example, it can be a combination of protective gas and oxygen, or a combination of protective gas and air; protective gas includes nitrogen and inert gas, etc., and an adaptive combination can be made according to actual needs and production process).

[0045] Preferably, the volume fraction of oxygen in the micro-oxygen atmosphere is 1-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0046] In this application, if the volume fraction of oxygen in the micro-oxygen atmosphere is too large, exceeding 10%, the oxygen content in the mixed gas is too high, which will cause serious oxidation of the material, the primary particles are extremely thin, abnormal particle growth occurs, and the tap density is relatively low; while if the volume fraction is too small, less than 1%, the oxygen content in the mixed gas is too low to achieve the effect of micro-oxidation, and it is easy to cause agglomeration of secondary particles during the reaction process, and the sphericity is very poor; further preferably, the volume fraction of oxygen is 4-6%, which can more effectively achieve the concentrated distribution of particles.

[0047] As a preferred technical solution, the preparation method includes the following steps:

[0048] A main metal element mixed salt solution with a mass concentration of 80-120 g / L, a liquid alkali solution with a mass concentration of 10-30%, and an ammonia water solution with a mass concentration of 10-20% are added to the bottom liquid in parallel flow. In a micro-oxygen atmosphere with an oxygen volume fraction of 1-10% and an environment with a pH value of 8-13, at 20-80 °C, a coprecipitation reaction is carried out at a reaction speed of 100-400 r / min in a reaction kettle with a thickener for 100-150 h to obtain the narrow particle size distribution cathode precursor.

[0049] The main metal element in the main metal element mixed salt solution is the same as the metal elements in a Co b Mn c R z where 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2.

[0050] In a third aspect, an embodiment of this application provides a cathode material, which is obtained by mixing and sintering the narrow particle size distribution cathode precursor as described in the first aspect with a lithium source.

[0051] The cathode material obtained from the narrow particle size distribution cathode precursor material provided by this application also has a relatively concentrated particle size, uniform particle morphology, and stable structure.

[0052] Preferably, the sintering is carried out in an air atmosphere.

[0053] Preferably, the sintering temperature is 600-800 °C, such as 600 °C, 650 °C, 700 °C, 750 °C or 800 °C, etc.

[0054] Preferably, the sintering time is 6-15 h, such as 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h or 15 h, etc.

[0055] In a fourth aspect, an embodiment of this application provides a lithium-ion battery, which includes the cathode material as described in the third aspect.

[0056] Compared with the related art, the embodiments of the present application have the following beneficial effects:

[0057] The positive electrode precursor material provided in the embodiment of the present application has a (D90-D10) / D50 value within the range of less than 0.8, a uniform distribution of nickel, cobalt and manganese elements, a concentrated particle size distribution, a high sphericity, a uniform particle morphology, a stable structure and a high tap density, so that the obtained positive electrode material has a stable structure, uniform particles and good electrochemical properties.

[0058] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation to the technical solution of this article.

[0060] FIG1 is a SEM image of the positive electrode precursor provided in Example 2.

[0061] FIG2 is a SEM image of the positive electrode precursor provided in Comparative Example 1. DETAILED DESCRIPTION

[0062] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0063] Example 1

[0064] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0065] The preparation method of the positive electrode precursor is as follows:

[0066] A 2 mol / L nickel-cobalt-manganese mixed sulfate solution (the molar ratio in the mixed salt solution is Ni:Co:Mn=0.7:0.1:0.2), a 32% mass alkali solution, and an 18% mass ammonia solution are added concurrently to a reactor with a concentrator containing a bottom liquid with a temperature of 70°C, an ammonia concentration of 20 g / L, and a pH of 13.0, and a co-precipitation reaction is carried out at a stirring rate of 400 r / min for 100 h (nitrogen is introduced for reaction). During the reaction, the pH of the reaction system is controlled to be 12.5, the ammonia concentration is 20 g / L, and the temperature is 70°C. The particle size is continuously monitored. Before the particle size reaches the requirement, the concentrating reaction is continued. When the particle size D50 reaches 4 μm, the feeding is stopped and the reaction is continued until the material reaction is complete to obtain a ternary precursor.

[0067] Example 2

[0068] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0069] The difference between this embodiment and embodiment 1 is that a mixed gas of nitrogen and air (the volume fraction of oxygen is 5%) is introduced into the present embodiment.

[0070] The rest of the preparation methods and parameters were the same as those in Example 1.

[0071] Example 3

[0072] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0073] The difference between this embodiment and embodiment 1 is that the coprecipitation reaction time in this embodiment is 80 hours.

[0074] The rest of the preparation methods and parameters were the same as those in Example 1.

[0075] Example 4

[0076] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0077] The difference between this embodiment and embodiment 1 is that the reactor in this embodiment does not contain a thickener, but a mixed gas of nitrogen and air (the volume fraction of oxygen is 5%) is introduced during the co-precipitation reaction.

[0078] The rest of the preparation process and parameters remained the same as in Example 1.

[0079] Example 5

[0080] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0081] The difference between this embodiment and embodiment 1 is that the reactor in this embodiment does not contain a concentrator, but a mixed gas of nitrogen and air (the volume fraction of oxygen is 6%) is introduced during the co-precipitation reaction.

[0082] The rest of the preparation process and parameters remained the same as in Example 1.

[0083] Example 6

[0084] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.25 Mn 0.75 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0085] The preparation method of the positive electrode precursor is as follows:

[0086] A 3 mol / L nickel-manganese mixed nitrate solution (the molar ratio in the mixed salt solution is Ni:Mn=0.75:0.25), a 6 mol / L sodium carbonate solution and an 18% mass concentration of ammonia solution are added concurrently to a reactor containing a base liquid with a temperature of 80°C, an ammonia concentration of 15 g / L and a pH of 11.1, and a co-precipitation reaction is carried out at a stirring rate of 200 r / min for 150 hours (nitrogen is introduced). During the reaction, the pH of the reaction system is controlled to be 10, the ammonia concentration is 14 g / L, and the temperature is 80°C. The particle size is continuously monitored. Before the particle size reaches the requirement, the reaction process uses a reactor with a concentrator to carry out a concentrated reaction. When the particle size D50 reaches 10 μm, the feeding is stopped and the reaction is continued until the material reaction is complete to obtain a ternary precursor.

[0087] Example 7

[0088] This embodiment provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni0.25 Mn 0.75 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0089] The difference between this embodiment and embodiment 6 is that a mixed gas of nitrogen and air (the volume fraction of oxygen is 5%) is introduced into the present embodiment.

[0090] The remaining preparation methods and parameters were consistent with those in Example 6.

[0091] Comparative Example 1

[0092] This comparative example provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.70 Co 0.1 Mn 0.2 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0093] The difference between this embodiment and embodiment 1 is that the reaction time of the coprecipitation reaction in this embodiment is 80 hours, and the reactor is not equipped with a thickener, that is, no thickening reaction is performed.

[0094] The rest of the preparation methods and parameters were the same as those in Example 1.

[0095] Comparative Example 2

[0096] This comparative example provides a positive electrode precursor material with a narrow particle size distribution. The chemical formula of the positive electrode precursor material is Ni 0.25 Mn 0.75 (OH)2, the diameter distance (D90-D10) / D50 is shown in Table 1.

[0097] The difference between this embodiment and embodiment 7 is that the reaction time of the coprecipitation reaction in this embodiment is 80 hours, and the reactor is not equipped with a thickener, that is, no thickening reaction is performed.

[0098] The remaining preparation methods and parameters were consistent with those in Example 7.

[0099] Figure 1 shows an SEM image of the positive electrode precursor provided in Example 2, and Figure 2 shows an SEM image of the positive electrode precursor provided in Comparative Example 1. From the comparison between Figure 1 and Figure 2, it can be seen that the precursor positive electrode material obtained by the preparation method provided in the present application has highly uniform particles, concentrated particle size distribution, and good sphericity.

[0100] Table 1 shows the diameter distance (D90-D10) / D50 and some preparation parameters of the positive electrode precursors provided by Examples 1-7 and Comparative Examples 1-2.

[0101] Table 1

[0102] From Table 1 we can conclude that:

[0103] From the data results of Examples 1-7 and Comparative Examples 1-2, it can be seen that the present application achieves the purpose of improving the concentration of particle size by prolonging the co-precipitation reaction time or conducting a concentrated reaction or performing morphology control under a micro-oxygen atmosphere. When the above three conditions are met at the same time, the particle size is more concentrated, the sphericity is good, and the tap density is more excellent.

[0104] Furthermore, the positive electrode precursors provided in Example 1, Example 7 and Comparative Examples 1-2 were respectively mixed with lithium hydroxide (the molar ratio of the sum of the metal elements to lithium was 1:1.2) by a high-speed mixer, and sintered in a box furnace under an air atmosphere at a sintering temperature of 780°C and a high-temperature sintering time of 12 hours. After cooling to room temperature, they were crushed and sieved to obtain the corresponding positive electrode materials.

[0105] The positive electrode materials provided in Example 2, Example 7 and Comparative Examples 1-2 were used to prepare positive electrode sheets. The specific preparation process was as follows:

[0106] The positive electrode materials provided in Example 2, Example 7 and Comparative Examples 1-2 were respectively mixed with carbon nanotubes and polyvinylidene fluoride in a mass ratio of 95:3:2 and N-methylpyrrolidone (NMP) to obtain positive electrode slurry. The positive electrode slurry was coated on both sides of the aluminum foil surface, and the corresponding positive electrode sheet was obtained after drying and rolling.

[0107] The positive electrode sheets provided in Example 2, Example 7 and Comparative Examples 1-2 were used as positive electrodes, and the lithium sheet was used as a counter electrode to obtain button batteries.

[0108] The batteries provided in Example 2, Example 7 and Comparative Examples 1-2 were subjected to electrochemical performance tests. The test conditions were: capacity and cycle performance tests were performed at 0.1C. The test results are shown in Table 2.

[0109] Table 2

[0110] From Table 2 we can conclude that:

[0111] From the data results of Example 2 and Comparative Example 1, and Example 7 and Comparative Example 2, it can be seen that the more concentrated the particle size distribution of the precursor particles is and the higher the sphericity is, the better the electrochemical performance of the obtained positive electrode material is.

[0112] In summary, the positive electrode precursor material provided by the present application has a (D90-D10) / D50 in the range of less than 0.8, a uniform distribution of nickel, cobalt and manganese elements, a concentrated particle size distribution, a high sphericity, a uniform particle morphology, a stable structure and a high tap density, so that the obtained positive electrode material has a stable structure, uniform particles and good electrochemical properties.

[0113] The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in this application fall within the protection scope and disclosure scope of this application.

Claims

1. A positive electrode precursor with a narrow particle size distribution, wherein: The chemical general formula of the positive electrode precursor is Ni a Co b Mn c R z , where R includes hydroxide and / or carbonate, 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2; The (D90-D10) / D50 of the positive electrode precursor is less than 0.

8.

2. The positive electrode precursor with a narrow particle size distribution according to claim 1, wherein 0.3≤(D90-D10) / D50≤0.

5.

3. The positive electrode precursor with a narrow particle size distribution according to claim 1 or 2, wherein: The positive electrode precursor with narrow particle size distribution also includes doping elements.

4. The positive electrode precursor with narrow particle size distribution according to any one of claims 1 to 3, wherein: The D50 of the positive electrode precursor with narrow particle size distribution is 1 to 20 μm.

5. A method for preparing a positive electrode precursor with a narrow particle size distribution as claimed in any one of claims 1 to 4, comprising the following steps: Adding a main metal element mixed salt solution, a precipitant solution and a complexing agent solution into the base solution in parallel to perform a coprecipitation reaction to obtain the positive electrode precursor with a narrow particle size distribution; Among them, the main metal element in the main metal element mixed salt solution is consistent with the metal elements in Ni a Co b Mn c R z where 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2.

6. The method for preparing a positive electrode precursor with a narrow particle size distribution according to claim 5, wherein: The mass concentration of the main metal element mixed salt solution is 80-120 g / L.

7. The method for preparing a positive electrode precursor with a narrow particle size distribution according to claim 5 or 6, wherein: The precipitant solution includes a liquid alkali solution and / or a sodium carbonate solution.

8. The method for preparing a positive electrode precursor with a narrow particle size distribution according to any one of claims 5 to 7, wherein: The mass concentration of the liquid alkali solution is 10-30%.

9. The method for preparing a positive electrode precursor with a narrow particle size distribution according to any one of claims 5 to 8, wherein: The molar concentration of the sodium carbonate solution is 1 to 10 mol / L; Preferably, the complexing agent solution comprises an aqueous ammonia solution; Preferably, the mass concentration of the aqueous ammonia solution is 10-20%; Preferably, the solution added in parallel also includes a dopant solution.

10. The method for preparing a positive electrode precursor with a narrow particle size distribution according to any one of claims 5 to 9, wherein: The pH value of the base liquid is 8 to 13; Preferably, the mass concentration of the complexing agent in the base solution is 0 to 120 g / L; Preferably, the pH value during the coprecipitation reaction is 8 to 13; Preferably, the reaction temperature during the coprecipitation reaction is 20 to 80°C; Preferably, the reaction speed during the coprecipitation reaction is 100 to 400 r / min; Preferably, the reaction time of the coprecipitation reaction is 100 to 150 hours.

11. The method for preparing a positive electrode precursor with a narrow particle size distribution according to any one of claims 5 to 10, wherein: The coprecipitation reaction includes a thickening reaction; Preferably, the concentration reaction is carried out in a reactor equipped with a concentrator; Preferably, the coprecipitation reaction is carried out in a micro-oxygen atmosphere; Preferably, the volume fraction of oxygen in the micro-oxygen atmosphere is 1-10%.

12. The method for preparing a positive electrode precursor with a narrow particle size distribution according to any one of claims 5 to 11, comprising the following steps: A main metal element mixed salt solution with a mass concentration of 80 to 120 g / L, a liquid alkali solution with a mass concentration of 10 to 30%, and an ammonia solution with a mass concentration of 10 to 20% are added to the bottom liquid in parallel, and a co-precipitation reaction is carried out in a reactor with a thickener at a reaction speed of 100 to 400 r / min for 100 to 150 hours at a temperature of 20 to 80° C. in a micro-oxygen atmosphere with an oxygen volume fraction of 1 to 10% and a pH value of 8 to 13 to obtain the positive electrode precursor with a narrow particle size distribution; The main metal element in the main metal element mixed salt solution is the same as that of Ni a Co b Mn c R z and the metal elements in it are consistent, where 0 < a ≤ 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c = 1, 1 ≤ z ≤ 2.

13. A positive electrode material, wherein: The positive electrode material is obtained by mixing and sintering the positive electrode precursor with a narrow particle size distribution as described in any one of claims 1 to 4 and a lithium source.

14. The positive electrode material according to claim 13, wherein The sintering is carried out in an air atmosphere; Preferably, the sintering temperature is 600-800°C; Preferably, the sintering time is 6 to 15 hours.

15. A lithium ion battery, wherein: The lithium-ion battery comprises the positive electrode material according to claim 13 or 14.

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