阅读说明：本技术 一种制备ncm高镍三元正极材料前驱体的方法 (Method for preparing precursor of NCM high-nickel ternary cathode material ) 是由 康杰 颜志梁 石小东 钟姝 张东学 王隆肇 郑承辉 孔令瑞 黄萍 其他发明人请求不 于 2020-06-12 设计创作，主要内容包括：本发明涉及新能源汽车用锂离子动力电池技术领域,具体涉及一种制备NCM高镍三元正极材料前驱体的方法,采用镍、锰、钴的可溶性硫酸盐为原料,采用共沉淀反应工艺,反应期间使用绿色络合剂酒石酸钾钠和氨水进行分阶段络合,后经过陈化、洗涤、干燥、筛分、磁选五个工序得到高球型度、粗晶须的NCM三元前驱体；配制一定浓度的镍钴锰盐溶液,按照一定比例加入酒石酸钾钠组成的混合溶液,采用氢氧化钠的水溶液做为沉淀剂,进行共沉淀反应；最后将所得的产物进行陈化、洗涤、干燥,筛分、磁选得到高镍前驱体。采用本发明的制备方法可以制得高球型度、粗晶须且具有良好指标的NCM高镍三元正极材料前驱体。(The invention relates to the technical field of lithium ion power batteries for new energy automobiles, in particular to a method for preparing a precursor of an NCM high-nickel ternary positive electrode material, which adopts soluble sulfates of nickel, manganese and cobalt as raw materials, adopts a coprecipitation reaction process, uses a green complexing agent of potassium sodium tartrate and ammonia water to perform staged complexation during the reaction, and then obtains the NCM ternary precursor with high sphericity and coarse crystal whiskers through five procedures of aging, washing, drying, screening and magnetic separation; preparing a nickel-cobalt-manganese salt solution with a certain concentration, adding a mixed solution consisting of potassium sodium tartrate according to a certain proportion, and carrying out coprecipitation reaction by using an aqueous solution of sodium hydroxide as a precipitator; and finally, aging, washing, drying, screening and magnetically separating the obtained product to obtain the high-nickel precursor. The preparation method can be used for preparing the precursor of the NCM high-nickel ternary cathode material with high sphericity, coarse crystal whiskers and good index.)

1. A method for preparing a precursor of an NCM high-nickel ternary cathode material is characterized by comprising the following steps:

s1: preparing soluble sulfate of nickel, cobalt and manganese into solution with the molar concentration of 1.0mo1/L-2.2mo1/L according to a certain proportion of nickel, cobalt and manganese ions, adding a certain amount of potassium sodium tartrate to form mixed solution, and sequentially adding sodium hydroxide solution with a certain concentration and ammonia water for coprecipitation to prepare mixed slurry;

s2: and aging, washing, drying, screening and magnetically separating the synthesized composite slurry to obtain the precursor of the NCM high-nickel ternary cathode material.

2. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 1, wherein the precursor comprises the following steps: the coprecipitation reaction process in S1 is carried out under a protective atmosphere.

3. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 1, wherein the precursor comprises the following steps: the pH value in the coprecipitation reaction process of S1 is 9-12; the coprecipitation reaction temperature is 40-60 ℃.

4. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 1, wherein the precursor comprises the following steps: the concentration of the complexing agent potassium sodium tartrate in the mixed solution in the S1 is 0.01-0.2 mol/L; the concentration of the sodium hydroxide solution is 4-8 mol/L; the concentration of the ammonia water is 0.1-0.5 mol/L.

5. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 1, wherein the precursor comprises the following steps: in the mixed solution of nickel, cobalt and manganese ions in S1, the molar ratio of the nickel, cobalt and manganese ions is x: y: z, wherein x + y + z is 1; the chemical formula of the precursor of the NCM high-nickel ternary cathode material is (Ni)_xCo_yMn_z)OH₂Wherein x + y + z is 1, x is not less than0.6。

6. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 1, wherein the precursor comprises the following steps: the coprecipitation reaction in S1 is divided into two stages: high pH nucleation and low pH growth; wherein, in the first stage, high pH nucleation is carried out, and potassium sodium tartrate is taken as a complexing agent, namely, the mixed solution reacts with sodium hydroxide with certain concentration; in the second stage of low pH growth, ammonia water and sodium potassium tartrate are used as complexing agents, namely, the ammonia water is added while the mixed solution reacts with sodium hydroxide with certain concentration.

7. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 6, wherein the precursor comprises the following steps: the pH control range of the high pH nucleation stage is 11-12; the pH control range of the low pH growth stage is 9-11.

8. The method for preparing the precursor of the NCM high-nickel ternary cathode material according to claim 6, wherein the precursor comprises the following steps: the low pH growth stage maintains an ammonia value of 4-7 g/L.

9. The method for preparing the precursor of the NCM high-nickel ternary positive electrode material according to any one of claims 6 to 8, wherein the precursor comprises the following steps: and in the second stage reaction process, a solid lifting device is adopted to concentrate the reaction slurry to lift the solid content.

Technical Field

The invention relates to the technical field of lithium ion power batteries for new energy automobiles, in particular to a method for preparing a precursor of an NCM high-nickel ternary positive electrode material.

Background

With the development of the new energy automobile industry, the demand on the ternary positive electrode material market of the power battery with high gram capacity, high voltage, long cycle and low cost is increased. The ternary positive electrode material also developed from the original NCM111 to NCM523 and NCM622, and NCM811 and NCA. The nickel content in the anode material is improved, the cobalt content is reduced, the gram capacity of the material is improved, and the cost of raw materials is reduced, so that the high nickel material is the key for improving the added value of the anode product and is a competitive high place for various large enterprises at home and abroad. For the ternary cathode material, the performance of the ternary cathode material is mainly influenced by the corresponding precursor, so that the ternary cathode material is very important for improving the preparation method of the nickel-cobalt-manganese precursor.

The main method for preparing the nickel-cobalt-manganese precursor at the present stage comprises the following steps: firstly, preparing nickel-cobalt-manganese solid salt into a mixed solution with a certain concentration and a certain proportion, and carrying out coprecipitation crystallization on the mixed solution, a precipitator and a complexing agent; and secondly, aging, washing, drying, sieving, removing iron and other processes are carried out on the crystallization slurry to obtain the nickel-cobalt-manganese hydroxide precursor.

Due to the characteristics of the ammonia complexing agent and the high-nickel precursor, when a high-nickel large-particle precursor product is prepared, the conditions of ball cracking, non-uniform particles and the like are easily caused in the reaction or the subsequent drying and screening process, and the performance of the subsequent anode material is further influenced by the precursor stage.

Disclosure of Invention

Aiming at the problems, the invention provides a method for preparing the precursor of the NCM high-nickel ternary cathode material, and the precursor of the NCM high-nickel ternary cathode material with high sphericity, coarse crystal whiskers and good indexes can be prepared by the method provided by the invention.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method for preparing a precursor of an NCM high-nickel ternary cathode material comprises the following steps:

s1: preparing soluble sulfate of nickel, cobalt and manganese into solution with the molar concentration of 1.0mo1/L-2.2mo1/L according to a certain proportion of nickel, cobalt and manganese ions, adding a certain amount of potassium sodium tartrate to form mixed solution, sequentially adding sodium hydroxide solution with a certain concentration and ammonia water, stirring and mixing to perform coprecipitation to prepare mixed slurry;

s2: and aging, washing, drying, screening and magnetically separating the synthesized composite slurry to obtain the precursor of the NCM high-nickel ternary cathode material.

Further, the coprecipitation reaction process in the S1 is carried out under a protective atmosphere; wherein the protective atmosphere is usually a nitrogen atmosphere.

Preferably, the pH value during the coprecipitation reaction in S1 is 9-12; the coprecipitation reaction temperature is 40-60 ℃.

Preferably, the concentration of the complexing agent potassium sodium tartrate in the mixed solution in the S1 is 0.01-0.2 mol/L; the concentration of the sodium hydroxide solution is 4-8 mol/L; the concentration of the ammonia water is 0.1-0.5 mol/L.

Further, in the mixed solution of nickel, cobalt and manganese ions in S1, the molar ratio of nickel, cobalt and manganese ions is x: y: z, wherein x + y + z is 1; the chemical formula of the precursor of the NCM high-nickel ternary cathode material is (Ni)_xCo_yMn_z)OH₂Wherein x + y + z is 1(x ≧ 0.6).

Further, the coprecipitation reaction in S1 is divided into two stages: high pH nucleation and low pH growth; wherein, in the first stage, high pH nucleation is carried out, and potassium sodium tartrate is taken as a complexing agent, namely, the mixed solution reacts with sodium hydroxide with certain concentration; in the second stage of low pH growth, ammonia water and sodium potassium tartrate are used as complexing agents, namely, the ammonia water is added while the mixed solution reacts with sodium hydroxide with certain concentration.

Preferably, the pH control range of the high pH nucleation stage is 11-12; the pH control range of the low pH growth stage is 9-11.

Preferably, the low pH growth stage maintains an ammonia value of 4 to 7 g/L.

Furthermore, in the second stage reaction process, a solid lifting device is adopted to concentrate the reaction slurry to lift the solid content.

The temperature of the drying process in S2 is 90-130 ℃; the stirring speed in the coprecipitation reaction process is 900-.

Compared with the prior art, the invention has the following beneficial effects:

the method for preparing the NCM high-nickel ternary material precursor provided by the technology can obtain the NCM high-nickel ternary positive electrode material precursor with high sphericity, compact surface and good index, and is controllable in equipment and related conditions and easy to operate.

Description of the figures

FIG. 1 is a process flow diagram illustrating a method for preparing a high-nickel ternary material precursor according to an embodiment of the present invention;

FIG. 2 is a 2000-fold scanning electron microscope image of the high-nickel ternary material precursor prepared in example 1 of the present invention;

FIG. 3 is a 5000-fold scanning electron microscope image of the high-nickel ternary material precursor prepared in example 1 of the present invention;

FIG. 4 is a 2000-fold scanning electron microscope image of the high-nickel ternary material precursor prepared in example 2 of the present invention;

fig. 5 is a 5000-fold scanning electron microscope image of the high-nickel ternary material precursor prepared in example 2 of the present invention.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention,