A nickel-cobalt-manganese ternary precursor with low specific surface area and its preparation method and application

Abstract

The present invention provides a nickel-cobalt-manganese ternary precursor with a low specific surface area, a preparation method and an application thereof. The method disclosed in the present invention improves the ammonia concentration of the reaction system by overall regulation of the production process, thereby greatly reducing the specific surface area of ​​the ternary precursor product, increasing the tap density, and reducing the particle size distribution. The specific surface area of ​​the product is 3-6 m 2 / g, tap density is 2-2.5g / cm 3 , the particle diameter is 0.5-0.8. Under the production conditions of relatively high ammonia concentration, the present invention solves the problem of product metal ratio deviation caused by excessively high ammonia concentration by reasonably regulating and optimizing process conditions such as the metal ratio of the raw material liquid and the pH range of the system, reduces the production difficulty of the product under excessively high ammonia concentration, overcomes the technical difficulties existing in the prior art, and prepares a large-particle nickel-cobalt-manganese ternary precursor product with low specific surface area and uniform particle size.

Description

Technical Field

[0001] The invention belongs to the technical field of ternary precursor preparation, and specifically relates to a nickel-cobalt-manganese ternary precursor with a low specific surface area, and a preparation method and application thereof. Background Art

[0002] In lithium-ion batteries, the ternary nickel-cobalt-manganese positive electrode material with a lower specific surface area has a small contact area with the electrolyte, which can effectively inhibit the side reaction between the surface of the positive electrode material and the electrolyte and improve the stability of the positive electrode material. However, in actual production, the specific surface area of ​​the prepared precursor is usually larger, because the actual production is mostly prepared under conditions of low ammonia concentration. In the preparation process of nickel-cobalt-manganese ternary precursors, the ammonia concentration condition has a greater influence on the specific surface area of ​​the product, and the precursor prepared under conditions of low ammonia concentration usually has a larger specific surface area. Therefore, in order to reduce the specific surface area, it is necessary to increase the ammonia concentration. However, the production difficulty of the product increases under conditions of higher ammonia concentrations, because under conditions of excessively high ammonia concentrations, the complexation of metal ions with ammonia will prevent the metal ions from being completely precipitated, which will result in a low actual nickel content in the product, and then lead to problems such as the deviation of the ratio of nickel, cobalt and manganese from the set value. Therefore, in actual production, precursors are rarely synthesized under conditions of excessively high ammonia concentrations. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a nickel-cobalt-manganese ternary precursor with a low specific surface area and a preparation method and application thereof, which specifically include the following contents:

[0004] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0005] (1) Adding a base liquid into a reaction device and introducing a protective gas;

[0006] (2) adding a ternary liquid, liquid alkali and aqueous ammonia to a reaction device for a coprecipitation reaction; controlling the temperature of the coprecipitation reaction to be 50-70° C. and the stirring speed to be 120-180 r / min; controlling the pH of the reaction system to be stable at 10-11 and the ammonia concentration to be maintained at 10-13 within 15-18 hours after the reaction starts; when the reaction time is ≥30 hours, increasing the molar ratio of the Ni metal element in the ternary liquid by 0.2-1.5, and reducing the molar ratio of the Co metal element in the ternary liquid by 0.2-1.5, while keeping the ratio of the Mn element unchanged. The specific method for adjusting the ratio of the elements in the ternary liquid can be to add materials as needed on the basis of the original ternary liquid, or to prepare a new ternary liquid, which is not limited here; when the D50 of the product particles reaches 17-20 μm, stopping the addition of materials;

[0007] (3) post-treating the product to obtain a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 3-6 m2 / g.

[0008] Preferably, the protective gas in step (1) is N2.

[0009] Preferably, the ternary liquid in step (2) is a solution in which the mass concentration of Ni, Co and Mn is 105-112 g / L; the molar ratio of Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=(46-58):(14-24):(21-32).

[0010] Preferably, the ternary liquid in step (2) is a sulfate solution of the three elements Ni, Co and Mn.

[0011] Preferably, the mass concentration of the liquid caustic soda in step (2) is 25-35%, and the addition flow rate of the liquid caustic soda is 60-80 L / h.

[0012] Preferably, the mass concentration of the ammonia water in step (2) is 10-20%, and the addition flow rate of the ammonia water is 30-50 L / h.

[0013] Preferably, the tap density of the nickel-cobalt-manganese ternary precursor with low specific surface area in step (3) is 2-2.5 g / cm 3 , the particle size distance is 0.5-0.8, and the particle size distance = (D90-D10) / D50.

[0014] A nickel-cobalt-manganese ternary precursor with low specific surface area prepared by the method disclosed by the invention.

[0015] A positive electrode material prepared by using the nickel-cobalt-manganese ternary precursor with low specific surface area prepared by the invention.

[0016] A lithium ion battery prepared by using the positive electrode material disclosed in the invention.

[0017] Beneficial effects of the present invention:

[0018] (1) The present invention improves the ammonia concentration of the reaction system by overall regulation of the production process, thereby significantly reducing the specific surface area of ​​the ternary precursor product, increasing the tap density, and reducing the particle size distribution. The specific surface area of ​​the product is 3-6 m 2 / g, tap density is 2-2.5g / cm 3 , the particle diameter distance is 0.5-0.8. The positive electrode material prepared by the ternary precursor product prepared by the present invention has a small contact area with the electrolyte, which can effectively inhibit the side reaction between the surface of the positive electrode material and the electrolyte and improve the stability of the positive electrode material.

[0019] (2) The method disclosed in the present invention solves the problem of product metal ratio deviation caused by excessively high ammonia concentration by reasonably regulating and optimizing process conditions such as the metal ratio of the raw material liquid and the pH range of the system under production conditions of relatively high ammonia concentration, reduces the difficulty of producing products under excessively high ammonia concentration, overcomes the technical difficulties existing in the prior art, and prepares a large-particle nickel-cobalt-manganese ternary precursor product with low specific surface area and uniform particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a SEM image of a precursor prepared by the method disclosed in the present invention;

[0021] Figure 2 This is an enlarged SEM image of the precursor prepared by the method disclosed in the present invention. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-2 The present invention is described in detail with specific embodiments. The embodiments shown below do not limit the invention described in the claims. In addition, the entire contents of the configurations shown in the following embodiments are not limited to the solutions required as the invention described in the claims.

[0023] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0024] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0025] (2) adding the ternary liquid, liquid alkali and aqueous ammonia to a reaction device for coprecipitation reaction; controlling the temperature of the coprecipitation reaction to be 50-70° C. (e.g., 52° C., 54° C., 56° C., 58° C., 60° C., 65° C., 68° C., etc.) and the stirring speed to be 120-180 r / min (e.g., 133 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min, etc.); controlling the pH of the reaction system to be stable at 15-18 h (e.g., 15.5 h, 16 h, 16.5 h, 17 h, 17.5 h, etc.) at the beginning of the reaction; 10-11 (e.g. 10.2, 10.5, 10.8, 10.9, etc.), the ammonia concentration is maintained at 10-13 (e.g. 10.5, 11, 11.5, 12, 12.5, etc.); when the reaction time is ≥30h (e.g. 31h, 32h, 33h, 34h, 35h, etc.), the molar ratio of Ni metal element in the ternary liquid is increased by 0.2-1.5 (e.g. 0.3, 0.4, 0.5, 0.7, 0.9, 1.0, 1.2, 1.4, etc.), and the molar ratio of cobalt metal in the ternary liquid is reduced by 0.2-1.5 (e.g. 0.3, 0.4, 0.5, 0.7, 0.9, 1.0, 1.2, 1.4, etc.). 5, 0.7, 0.9, 1.0, 1.2, 1.4, etc.); when the D50 of the product particles reaches 17-20 μm (for example, 18 μm, 19 μm, 19.5 μm, etc.), stop adding materials; the ternary liquid is a solution in which the mass concentration of Ni, Co, and Mn is 105-112 g / L (for example, 106 g / L, 108 g / L, 110 g / L, 111 g / L, etc.); the molar ratio of Ni, Co, and Mn in the ternary liquid is Ni:Co:Mn=(46-58):(14-24):(21-32); the ternary liquid is N The mass concentration of the liquid alkali is 25-35% (for example, 26%, 28%, 30%, 32%, 34%, etc.), and the flow rate of adding the liquid alkali is 60-80L / h (for example, 65L / h, 70L / h, 75L / h, 78L / h, etc.); the mass concentration of the ammonia water is 10-20% (for example, 12%, 14%, 16%, 18%, etc.), and the flow rate of adding the ammonia water is 30-50L / h (for example, 32L / h, 35L / h, 38L / h, 40L / h, 45L / h, 48L / h, etc.).

[0026] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 3-6 m 2 / g, tap density is 2-2.5g / cm 3 , the particle size distance is 0.5-0.8.

[0027] The SEM image of the precursor prepared by the method disclosed in the present invention is as follows: Figure 1-2 As shown in the figure, it can be seen that the product prepared by the present invention has the characteristics of low specific surface area, uniform particle size and large particles. The present invention improves the ammonia concentration of the reaction system by overall regulation of the production process, thereby greatly reducing the specific surface area of ​​the ternary precursor product, increasing the tap density, and reducing the particle size distribution. The specific surface area of ​​the product is 3-6m 2 / g, tap density is 2-2.5g / cm 3 , the particle size distance is 0.5-0.8. The positive electrode material prepared by the ternary precursor product prepared by the present invention has a small contact area with the electrolyte, which can effectively inhibit the side reaction between the surface of the positive electrode material and the electrolyte, and improve the stability of the positive electrode material. The method disclosed in the present invention, under the production conditions of higher ammonia concentration, by reasonably regulating and optimizing the process conditions such as the metal ratio of the raw material liquid and the pH range of the system, better solves the problem of product metal ratio deviation caused by excessive ammonia concentration, reduces the difficulty of product production under excessively high ammonia concentration, overcomes the technical difficulties existing in the prior art, and prepares a large-particle nickel-cobalt-manganese ternary precursor product with low specific surface area and uniform particle size. The nickel-cobalt-manganese ternary precursor with low specific surface area prepared by the method disclosed in the present invention can be used to prepare positive electrode materials, and then applied to lithium-ion batteries. The positive electrode material prepared by the precursor prepared by the method disclosed in the present invention has higher stability, and the obtained lithium-ion battery has a longer service life.

[0028] Example 1

[0029] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0030] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0031] (2) Adding a ternary liquid, liquid alkali and aqueous ammonia to a reaction device for a coprecipitation reaction; controlling the temperature of the coprecipitation reaction to be 50°C and the stirring speed to be 120 r / min; controlling the pH of the reaction system to be stable at 10 and the ammonia concentration to be maintained at 10 within 15 hours after the start of the reaction; increasing the molar ratio of the Ni element in the ternary liquid by 0.2 and reducing the molar ratio of the cobalt metal in the ternary liquid by 0.2 when the reaction time is 30 hours; stopping the addition of materials when the D50 of the product particles reaches 17 μm; the ternary liquid is a solution in which the mass concentration of the three elements Ni, Co and Mn is 105 g / L; the molar ratio of the three elements Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=46:14:21; the ternary liquid is a sulfate solution of the three elements Ni, Co and Mn; the mass concentration of the liquid alkali is 25%, and the addition flow rate of the liquid alkali is 60 L / h; the mass concentration of the aqueous ammonia is 10%, and the addition flow rate of the aqueous ammonia is 30 L / h.

[0032] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 6 m 2 / g, tap density is 2.0g / cm 3 , the particle size spacing is 0.8.

[0033] Example 2

[0034] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0035] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0036] (2) Adding a ternary liquid, liquid alkali and aqueous ammonia to a reaction device for a coprecipitation reaction; controlling the temperature of the coprecipitation reaction to be 70°C and the stirring speed to be 180 r / min; controlling the pH of the reaction system to be stable at 11 and the ammonia concentration to be maintained at 13 within 18 hours after the reaction starts; increasing the molar ratio of the Ni element in the ternary liquid by 1.5 and reducing the molar ratio of the cobalt metal in the ternary liquid by 1.5 when the reaction time is 31 hours; stopping the addition of materials when the D50 of the product particles reaches 20 μm; the ternary liquid is a solution in which the mass concentration of the three elements Ni, Co and Mn is 112 g / L; the molar ratio of the three elements Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=58:24:32; the ternary liquid is a sulfate solution of the three elements Ni, Co and Mn; the mass concentration of the liquid alkali is 35%, and the addition flow rate of the liquid alkali is 80 L / h; the mass concentration of the aqueous ammonia is 20%, and the addition flow rate of the aqueous ammonia is 50 L / h.

[0037] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 4 m 2 / g, tap density is 2.5g / cm 3 , the particle size spacing is 0.5.

[0038] Example 3

[0039] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0040] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0041] (2) adding ternary liquid, liquid alkali and ammonia water into a reaction device for coprecipitation reaction; controlling the temperature of the coprecipitation reaction to 60°C and the stirring speed to 150r / min; controlling the pH of the reaction system to be stable at 10.5-11 and the ammonia concentration to be maintained at 10-12 within 16 hours after the reaction starts; increasing the molar ratio of the Ni element in the ternary liquid by 0.5 and reducing the molar ratio of the cobalt metal in the ternary liquid by 0.5 when the reaction time is 33 hours; and when the D50 of the product particles reaches 18μ m, stop adding material; the ternary liquid is a solution in which the mass concentration of Ni, Co and Mn is 108 g / L; the molar ratio of Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=50:50:30; the ternary liquid is a sulfate solution of Ni, Co and Mn; the mass concentration of the liquid alkali is 28%, and the addition flow rate of the liquid alkali is 70 L / h; the mass concentration of the ammonia water is 15%, and the addition flow rate of the ammonia water is 45 L / h.

[0042] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 3 m 2 / g, tap density is 2.3g / cm 3 , the particle size distance is 0.6.

[0043] Example 4

[0044] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0045] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0046] (2) Adding ternary liquid, liquid alkali and ammonia water into a reaction device for coprecipitation reaction; controlling the temperature of the coprecipitation reaction to 55°C and the stirring speed to 140r / min; controlling the pH of the reaction system to be stable at 10-10.8 and the ammonia concentration to be maintained at 12-13 within 15.5h after the reaction starts; increasing the molar ratio of Ni element in the ternary liquid by 0.8 and reducing the molar ratio of cobalt metal in the ternary liquid by 0.8 when the reaction time is 32h; when the D50 of the product particles reaches 19 μm, stop adding material; the ternary liquid is a solution in which the mass concentration of Ni, Co and Mn is 110 g / L; the molar ratio of Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=55:21:28; the ternary liquid is a sulfate solution of Ni, Co and Mn; the mass concentration of the liquid alkali is 30%, and the addition flow rate of the liquid alkali is 75 L / h; the mass concentration of the ammonia water is 18%, and the addition flow rate of the ammonia water is 40 L / h.

[0047] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 5 m 2 / g, tap density is 2.2g / cm 3 , the particle size distance is 0.6.

[0048] Example 5

[0049] A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area comprises the following steps:

[0050] (1) Adding the base liquid into the reaction device and introducing the protective gas N2;

[0051] (2) Adding ternary liquid, liquid alkali and ammonia water into a reaction device for coprecipitation reaction; controlling the temperature of the coprecipitation reaction to 68°C and the stirring speed to 168r / min; controlling the pH of the reaction system to be stable at 10.4-10.6 and the ammonia concentration to be maintained at 11-12 within 16.5h after the reaction starts; increasing the molar ratio of Ni element in the ternary liquid by 1.2 and reducing the molar ratio of cobalt metal in the ternary liquid by 1.2 when the reaction time is 34h; when the D50 of the product particles reaches 1 8μm, stop adding; the ternary liquid is a solution of Ni, Co, and Mn with a mass concentration of 110g / L; the molar ratio of Ni, Co, and Mn in the ternary liquid is Ni:Co:Mn=52:23:29; the ternary liquid is a sulfate solution of Ni, Co, and Mn; the mass concentration of the liquid alkali is 32%, and the addition flow rate of the liquid alkali is 76L / h; the mass concentration of the ammonia water is 12%, and the addition flow rate of the ammonia water is 38L / h.

[0052] (3) subjecting the product to post-treatment such as aging, washing, dehydration, and drying, and finally obtaining a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 3.5 m 2 / g, tap density is 2.1g / cm 3 , the particle size distance is 0.7.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area, characterized in that: The following steps are involved: (1) Adding a base liquid into a reaction device and introducing a protective gas; (2) continuously adding ternary liquid, liquid alkali and ammonia water into the reaction device for coprecipitation reaction; the molar ratio of Ni, Co and Mn in the ternary liquid is Ni:Co:Mn=(46-58):(14-24):(21-32); controlling the temperature of the coprecipitation reaction to be 50-70°C and the stirring speed to be 120-180r / min; controlling the pH of the reaction system to be stable at 10-11 and the ammonia concentration to be maintained at 10-13 within 15-18h after the reaction starts; when the reaction time is ≥30h, increasing the molar ratio of Ni in the ternary liquid by 0.2-1.5, and reducing the molar ratio of Co in the ternary liquid by 0.2-1.5, while keeping the ratio of Mn unchanged; stopping the addition of materials when the D50 of the product particles reaches 17-20μm; (3) post-treating the product to obtain a nickel-cobalt-manganese ternary precursor product with a low specific surface area, wherein the specific surface area of ​​the nickel-cobalt-manganese ternary precursor with a low specific surface area is 3-6 m 2 / g.

2. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to claim 1, characterized in that: The protective gas in step (1) is N2.

3. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to claim 1, characterized in that: The ternary liquid in step (2) is a solution in which the mass concentration of the three elements Ni, Co and Mn is 105-112 g / L.

4. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to claim 3, characterized in that: The ternary liquid in step (2) is a sulfate solution of three elements: Ni, Co and Mn.

5. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to claim 3, characterized in that: The mass concentration of the liquid caustic soda in step (2) is 25-35%, and the addition flow rate of the liquid caustic soda is 60-80 L / h.

6. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to claim 3, characterized in that: The mass concentration of the ammonia water in step (2) is 10-20%, and the addition flow rate of the ammonia water is 30-50 L / h.

7. The method for preparing a nickel-cobalt-manganese ternary precursor with a low specific surface area according to any one of claims 1 to 6, characterized in that: The tap density of the nickel-cobalt-manganese ternary precursor with low specific surface area in step (3) is 2-2.5 g / cm 3 , the particle size distance is 0.5-0.

8.

8. A nickel-cobalt-manganese ternary precursor with low specific surface area prepared by the method according to claim 1.

9. A positive electrode material prepared using the nickel-cobalt-manganese ternary precursor with low specific surface area as claimed in claim 8.

10. A lithium ion battery prepared using the positive electrode material according to claim 9.

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