阅读说明：本技术 一种掺杂型锂离子电池用前驱体、正极材料及该前驱体和正极材料的制备方法 (Precursor for doped lithium ion battery, positive electrode material and preparation methods of precursor and positive electrode material ) 是由 许开华 蒋振康 张坤 陈康 李聪 黎俊 孙海波 范亮姣 于 2019-08-27 设计创作，主要内容包括：本发明公开了一种掺杂型锂离子电池用镍钴锰前驱体,该前驱体为放射形金属氢氧化物,化学表达式为：Ni_(0.7)Co_(0.1)Mn_(0.2-x)Mg_x(OH)_2,其中,0.02≤x≤0.04。本发明还公开了该镍钴锰前驱体的制备方法。本发明通过在共沉淀过程中直接加入Mg掺杂元素,使掺杂元素能够均匀的分布在前驱体颗粒中,从而有效的发挥掺杂元素的改性作用,而镁掺杂有助于形成良好的层状结构,增强材料结构稳定性,改善高镍三元材料的循环性能。(The invention discloses a nickel-cobalt-manganese precursor for a doped lithium ion battery, which is a radioactive metal hydroxide and has the chemical expression as follows: ni 0.7 Co 0.1 Mn 0.2‑x Mg x (OH) 2 Wherein x is more than or equal to 0.02 and less than or equal to 0.04. The invention also discloses a preparation method of the nickel-cobalt-manganese precursor. According to the invention, the Mg doping element is directly added in the coprecipitation process, so that the doping element can be uniformly distributed in the precursor particles, the modification effect of the doping element is effectively exerted, and the magnesium doping is beneficial to forming a good layered structure, enhancing the structural stability of the material and improving the cycle performance of the high-nickel ternary material.)

1. The nickel-cobalt-manganese precursor for the doped lithium ion battery is characterized by being a radioactive metal hydroxide, and having the chemical expression as follows: ni_0.7Co_0.1Mn_0.2-xMg_x(OH)₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04.

2. The nickel-cobalt-manganese precursor for the doped lithium ion battery according to claim 1, wherein the average particle size of the nickel-cobalt-manganese precursor for the doped lithium ion battery is 15-25 μm.

3. A positive electrode material for a lithium ion battery having the precursor of claim 1, wherein the positive electrode material has a molecular formula of LiNi_0.7Co_0.1Mn_0.2-x Mg_xO₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04.

4. A method for preparing the nickel-cobalt-manganese precursor for the doped lithium ion battery according to claim 1 or 2, wherein the method comprises the following steps:

step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.2-x: x (x is more than or equal to 0.02 and less than or equal to 0.04) is fully mixed with nickel salt, cobalt salt, manganese salt and magnesium salt to prepare a mixed salt solution for later use;

step 2, respectively adding the mixed salt solution, the alkali solution and the ammonia water in the step 1 into a reaction kettle in an inert gas atmosphere, and carrying out coprecipitation reaction under stirring;

step 3, when the granularity of the precursor particles in the reaction kettle reaches the required size, stopping the reaction, and transferring the materials in the reaction kettle to an ageing tankPerforming middle aging, then centrifugally washing and drying to obtain a radioactive nickel-cobalt-manganese precursor Ni_0.7Co_0.1Mn_0.2-xMg_x(OH)₂。

5. The method according to claim 4, wherein in step 1, the nickel salt is at least one of nickel chloride, nickel sulfate and nickel nitrate; the cobalt salt is at least one of cobalt chloride, cobalt sulfate and cobalt nitrate; the manganese salt is at least one of manganese chloride, manganese sulfate and manganese nitrate; the magnesium salt is at least one of magnesium chloride, magnesium sulfate and magnesium nitrate.

6. The method according to claim 5, wherein in the step 1, the concentration of nickel, cobalt, manganese and magnesium ions in the mixed salt solution is 1-3 mol/L.

7. The method for preparing the nickel-cobalt-manganese precursor for the doped lithium ion battery according to claim 6, wherein in the step 2, the molar concentration of the alkali solution is 3-5 mol/L, and the molar concentration of the ammonia water is 8-12 mol/L; the alkali in the alkali solution is sodium hydroxide or potassium hydroxide.

8. The method for preparing the nickel-cobalt-manganese precursor for the doped lithium ion battery according to any one of claims 4 to 7, wherein in the step 2, the reaction temperature of the coprecipitation reaction is 40 to 70 ℃, the reaction pH is 11 to 12.5, the stirring speed is 150 to 250rpm, and the reaction time is 60 to 90 hours.

9. The method for preparing the nickel-cobalt-manganese positive electrode material for the doped lithium ion battery according to claim 3, wherein the method comprises the following steps: mixing the precursor prepared by the preparation method of any one of claims 4 to 8 with a lithium source, and sintering at high temperature in an atmosphere furnace filled with oxygen to obtain doped lithium ionsNickel-cobalt-manganese positive electrode material LiNi for sub-battery_0.7Co_0.1Mn_0.2-x Mg_xO₂。

10. The method for preparing the nickel-cobalt-manganese positive electrode material for the doped lithium ion battery according to claim 9, wherein the ratio of lithium is 1.05, the sintering temperature is 700-900 ℃, and the sintering time is 9-14 h.

Technical Field

The invention belongs to the technical field of battery materials, and particularly relates to a precursor and a positive electrode material for a doped lithium ion battery, and preparation methods of the precursor and the positive electrode material.

Background

In the face of the increasing energy demand due to the continuous development of science and technology and the environmental problems caused by the use of fossil energy, Lithium Ion Batteries (LIBs) are distinguished by the advantages of high specific energy, small self-discharge, high open circuit voltage, no memory effect, long cycle life, small environmental pollution and the like; the anode material is a key component of the lithium ion battery, not only takes part in electrochemical reaction as an electrode material, but also serves as a lithium ion source, and determines the safety, performance, cost and service life of the battery to a great extent; with the continuous expansion and extension of the application scenes of the lithium ion battery, the capacity requirement of the lithium ion battery is higher and higher. The layered nickel-cobalt-manganese ternary composite cathode material is a novel lithium ion battery cathode material which is mainstream at present, and under the conventional working voltage of a 4.4V lithium ion battery, the higher the content of nickel in the cathode material is, and the larger the specific capacity of the material is. Under such circumstances, high nickel ternary positive electrode materials represented by 622, 712, 811, and the like have attracted more and more attention and have become hot spots of research in recent years. However, due to ternary LiNi_1-x-yCo_xMn_yO₂The characteristics of the self structure of the anode material are that the thermal stability, the cycle performance and the rate performance of the material are not satisfactory with the continuous increase of the nickel content. In order to improve the comprehensive electrochemical performance of the high-nickel ternary material, researchers have proposed various methods, the methods commonly used at present are mainly ion doping and surface coating, and relatively few researches have focused on improving some problems of the high-nickel ternary material by regulating the internal structure of the material.

Disclosure of Invention

In view of the above, the main object of the present invention is to provide a nickel-cobalt-manganese precursor for a doped lithium ion battery, which solves the problems of poor stability, cycle performance and rate capability and low specific discharge capacity of the existing materials; the invention also aims to provide a preparation method of the precursor, a positive electrode material prepared from the precursor and a preparation method of the positive electrode material.

In order to achieve the purpose, the technical scheme of the invention is realized as follows: a nickel-cobalt-manganese precursor for a doped lithium ion battery is a radioactive metal hydroxide, and has the chemical expression: ni_0.7Co_0.1Mn_0.2-xMg_x(OH)₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04.

Preferably, the average particle size of the nickel-cobalt-manganese precursor for the doped lithium ion battery is 15-25 μm.

The second technical scheme of the invention is realized as follows: the precursor is used as the anode material for the lithium ion battery, and the molecular formula of the anode material is LiNi_0.7Co_0.1Mn_0.2-xMg_xO₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04.

The third technical scheme of the invention is realized as follows: a preparation method of a nickel-cobalt-manganese precursor for a doped lithium ion battery is characterized by comprising the following steps:

step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.2-x: x (x is more than or equal to 0.02 and less than or equal to 0.04) is fully mixed with nickel salt, cobalt salt, manganese salt and magnesium salt to prepare a mixed salt solution for later use;

step 2, respectively adding the mixed salt solution, the alkali solution and the ammonia water in the step 1 into a reaction kettle through a metering pump in an inert gas atmosphere, and stirring for coprecipitation reaction;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an ageing tank for ageing, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni_0.7Co_0.1Mn_0.2-xMg_x(OH)₂。

Preferably, in the step 1, the nickel salt is at least one of nickel chloride, nickel sulfate and nickel nitrate; the cobalt salt is at least one of cobalt chloride, cobalt sulfate and cobalt nitrate; the manganese salt is at least one of manganese chloride, manganese sulfate and manganese nitrate; the magnesium salt is at least one of magnesium chloride, magnesium sulfate and magnesium nitrate.

Preferably, in the step 1, the concentration of nickel, cobalt, manganese and magnesium ions in the mixed salt solution is 1-3 mol/L.

Preferably, in the step 2, the molar concentration of the alkali solution is 3-5 mol/L, and the molar concentration of the ammonia water is 8-12 mol/L; the alkali in the alkali solution is sodium hydroxide or potassium hydroxide.

Preferably, in the step 2, the reaction temperature of the coprecipitation reaction is 40-70 ℃, the reaction pH is 11-12.5, the stirring speed is 150-250 rpm, and the reaction time is 60-90 h.

The fourth technical scheme of the invention is realized as follows: a preparation method of a nickel-cobalt-manganese positive electrode material for a doped lithium ion battery is characterized by comprising the steps of mixing a precursor prepared by the preparation method with a lithium source, and sintering at a high temperature in an atmosphere furnace filled with oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.2-xMg_xO₂。

Preferably, the proportion of lithium is 1.05, the sintering temperature is 700-900 ℃, and the sintering time is 9-14 h.

According to the invention, the Mg doping element is directly added in the coprecipitation process, so that the doping element can be uniformly distributed in the precursor particles, the modification effect of the doping element is effectively exerted, and the magnesium doping is beneficial to forming a good layered structure, enhancing the structural stability of the material and improving the cycle performance of the high-nickel ternary material. By controlling the synthesis process of the precursor, primary particles are directionally arranged to form a radial structure from inside to outside, and the precursor particles grow radially from inside to outside, so that the lithium salt is favorably diffused in the precursor particles in the sintering process for preparing the anode material, the reaction is more sufficient, the prepared ternary anode material can form a lithium ion diffusion channel from inside to outside, the radial structure is favorable for the extraction and the insertion of lithium ions, and the particle structure is more stable, so that the excellent electrochemical performance is shown.

Drawings

FIG. 1 is an SEM image of a Ni-Co-Mn precursor obtained in example 1 of the present invention;

fig. 2 is an SEM image of the nickel-cobalt-manganese precursor obtained in example 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the invention provides a nickel-cobalt-manganese precursor for a doped lithium ion battery, which is a radioactive metal hydroxide and has the chemical expression as follows: ni_0.7Co_0.1Mn_0.2-xMg_x(OH)₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04, and the average particle size of the nickel-cobalt-manganese precursor for the doped lithium ion battery is 15-25 mu m.

The embodiment of the invention also provides a positive electrode material for the lithium ion battery, which has the precursor, and the molecular formula of the positive electrode material is LiNi_0.7Co_0.1Mn_0.2-xMg_xO₂Wherein x is more than or equal to 0.02 and less than or equal to 0.04.

The embodiment of the invention also provides a preparation method of the nickel-cobalt-manganese precursor for the doped lithium ion battery, which comprises the following steps:

step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.2-x: x (x is more than or equal to 0.02 and less than or equal to 0.04) is fully mixed with nickel salt, cobalt salt, manganese salt and magnesium salt to prepare a mixed salt solution for later use;

wherein the nickel salt is at least one of nickel chloride, nickel sulfate and nickel nitrate; the cobalt salt is at least one of cobalt chloride, cobalt sulfate and cobalt nitrate; the manganese salt is at least one of manganese chloride, manganese sulfate and manganese nitrate; the magnesium salt is at least one of magnesium chloride, magnesium sulfate and magnesium nitrate; the concentration of nickel, cobalt, manganese and magnesium ions in the mixed salt solution is 1-3 mol/L;

step 2, respectively adding the mixed salt solution, the alkali solution and the ammonia water in the step 1 into a reaction kettle through a metering pump in an inert gas atmosphere, and stirring for coprecipitation reaction;

wherein the molar concentration of the alkali solution is 3-5 mol/L, and the molar concentration of the ammonia water is 8-12 mol/L; the alkali in the alkali solution is sodium hydroxide or potassium hydroxide; the reaction temperature of the coprecipitation reaction is 40-70 ℃, the reaction pH is 11-12.5, the stirring speed is 150-250 rpm, and the reaction time is 60-90 h.

And 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 15-25 mu m_0.7Co_0.1Mn_0.2-xMg_x(OH)₂。

The embodiment of the invention also provides a preparation method of the nickel-cobalt-manganese anode material for the doped lithium ion battery, which comprises the steps of mixing the precursor obtained by the preparation method with a lithium source, and sintering at high temperature in an atmosphere furnace filled with oxygen to obtain the nickel-cobalt-manganese anode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.2-xMg_xO₂(ii) a Wherein the proportion of lithium is 1.05, the sintering temperature is 700-900 ℃, and the sintering time is 9-14 h.

After the scheme is adopted, the Mg doping element is directly added in the coprecipitation process, so that the doping element can be uniformly distributed in the precursor particles, the modification effect of the doping element is effectively exerted, the magnesium doping is beneficial to forming a good layered structure, the structural stability of the material is enhanced, and the cycle performance of the high-nickel ternary material is improved. By controlling the synthesis process of the precursor, primary particles are directionally arranged to form a radial structure from inside to outside, and the precursor particles grow radially from inside to outside, so that the lithium salt is favorably diffused in the precursor particles in the sintering process for preparing the anode material, the reaction is more sufficient, the prepared ternary anode material can form a lithium ion diffusion channel from inside to outside, the radial structure is favorable for the extraction and the insertion of lithium ions, and the particle structure is more stable, so that the excellent electrochemical performance is shown.

Example 1

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.18: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.02(9:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 2mol/L for later use;

step 2, respectively adding the mixed salt solution, a sodium hydroxide solution with the concentration of 4mol/L and ammonia water with the concentration of 10mol/L into a reaction kettle through a metering pump in the nitrogen atmosphere, controlling the pH of the system to be 11-12.5 in the feeding process, and then carrying out coprecipitation reaction for 75 hours at the temperature of 55 ℃ and the stirring speed of 200 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 20 mu m_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂。

The precursor is radial as can be clearly seen in figure 1;

2) preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂Mixing with lithium source, and sintering at 800 deg.C in an atmosphere furnace filled with oxygen for 11h to obtain doped lithium ionNickel-cobalt-manganese positive electrode material LiNi for battery_0.7Co_0.1Mn_0.18Mg_0.02O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 2

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.18: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.02(9:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 1mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3mol/L and ammonia water with the concentration of 8mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and then carrying out coprecipitation reaction for 90 hours at the temperature of 40 ℃ and the stirring speed of 150 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain a radial nickel-cobalt-manganese precursor Ni with the granularity of 15 mu m_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂。

The precursor is radial as can be clearly seen in figure 2;

2) preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂Mixing with a lithium source, and sintering at high temperature for 14h in an atmosphere furnace with 700 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 3

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.18: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.02(9:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 3mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3-5 mol/L and ammonia water with the concentration of 5mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and performing coprecipitation reaction for 60 hours at the temperature of 70 ℃ and the stirring speed of 250 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 25 mu m_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.18Mg_0.02(OH)₂Mixing with a lithium source, and sintering at high temperature for 9h in an atmosphere furnace with 900 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 4

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.16: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.04(4:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 2mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3mol/L and ammonia water with the concentration of 8mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and then carrying out coprecipitation reaction for 90 hours at the temperature of 40-70 ℃ and the stirring speed of 150 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 20 mu m_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂Mixing with a lithium source, and sintering at high temperature for 14h in an atmosphere furnace with 700 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂: (ii) a Wherein the proportion of lithium is 1.05.

Example 5

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.16: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.04(4:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 2mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3-5 mol/L and ammonia water with the concentration of 5mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and performing coprecipitation reaction for 60 hours at the temperature of 70 ℃ and the stirring speed of 250 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 20 mu m_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂Mixing with a lithium source, and sintering at high temperature for 9h in an atmosphere furnace with 900 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 6

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.17: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.03 to prepare a mixed salt solution with the concentration of nickel ions, cobalt ions, manganese ions and magnesium ions being 1mol/L for later use;

step 2, respectively adding the mixed salt solution, a sodium hydroxide solution with the concentration of 4mol/L and ammonia water with the concentration of 10mol/L into a reaction kettle through a metering pump in the nitrogen atmosphere, controlling the pH of the system to be 11-12.5 in the feeding process, and then carrying out coprecipitation reaction for 75 hours at the temperature of 55 ℃ and the stirring speed of 200 rpm;

step 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required sizeTransferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain a radial nickel-cobalt-manganese precursor Ni with the particle size of 15 mu m_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.17Mg_0.03O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂Mixing with a lithium source, and sintering at high temperature for 11h in an atmosphere furnace with oxygen at 800 ℃ to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.17Mg_0.03O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 7

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.17: fully mixing nickel sulfate, cobalt sulfate, manganese sulfate and magnesium sulfate according to the proportion of 0.03 to prepare a mixed salt solution with the concentration of nickel ions, cobalt ions, manganese ions and magnesium ions being 1mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3-5 mol/L and ammonia water with the concentration of 5mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and performing coprecipitation reaction for 60 hours at the temperature of 70 ℃ and the stirring speed of 250 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 15 mu m_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂。

2) Preparation of Ni-Co-Mn alloy for doped lithium ion batteryPositive electrode material LiNi_0.7Co_0.1Mn_0.17Mg_0.03O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.17Mg_0.03(OH)₂Mixing with a lithium source, and sintering at high temperature for 9h in an atmosphere furnace with 900 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.17Mg_0.03O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 8

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.16: mixing nickel chloride, cobalt chloride, manganese chloride and magnesium chloride fully according to the proportion of 0.04(4:1) to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 3mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3-5 mol/L and ammonia water with the concentration of 5mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and performing coprecipitation reaction for 60 hours at the temperature of 70 ℃ and the stirring speed of 250 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 25 mu m_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.16Mg_0.04(OH)₂Mixing with lithium source, and introducing oxygen at 800 deg.CSintering the mixture for 11 hours at high temperature in a gas atmosphere furnace to obtain the nickel-cobalt-manganese anode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.16Mg_0.04O₂(ii) a Wherein the proportion of lithium is 1.05.

Example 9

1) Preparation of Ni-Co-Mn precursor for doped lithium ion battery_0.7Co_0.1Mn_0.08Mg_0.02(OH)₂；

Step 1, mixing the components in a molar ratio of Ni: co: (Mn + Mg) 7: 1: 2 and Mn: mg is 0.18: 0.02(9:1), fully mixing nickel nitrate, cobalt nitrate, manganese nitrate and magnesium nitrate to prepare a mixed salt solution with the concentration of nickel, cobalt, manganese and magnesium ions being 3mol/L for later use;

step 2, in an inert gas atmosphere, adding the mixed salt solution, a sodium hydroxide solution with the concentration of 3mol/L and ammonia water with the concentration of 8mol/L into a reaction kettle through a metering pump respectively, controlling the pH of the system to be 11-12.5 in the feeding process, and then carrying out coprecipitation reaction for 90 hours at the temperature of 40-70 ℃ and the stirring speed of 150 rpm;

and 3, stopping the reaction when the granularity of the precursor particles in the reaction kettle reaches the required size, transferring the materials in the reaction kettle to an aging tank for aging, and then centrifugally washing and drying to obtain the radial nickel-cobalt-manganese precursor Ni with the granularity of 25 mu m_0.7Co_0.1Mn_0.08Mg_0.02(OH)₂。

2) Preparation of nickel-cobalt-manganese anode material LiNi for doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂：

The radioactive nickel-cobalt-manganese precursor Ni is_0.7Co_0.1Mn_0.08Mg_0.02(OH)₂Mixing with a lithium source, and sintering at high temperature for 14h in an atmosphere furnace with 700 ℃ and oxygen to obtain the nickel-cobalt-manganese positive electrode material LiNi for the doped lithium ion battery_0.7Co_0.1Mn_0.18Mg_0.02O₂(ii) a Wherein the proportion of lithium is 1.05.

Assembling a button cell and detecting:

the nickel-cobalt-manganese positive electrode material for the doped lithium ion battery obtained in examples 1 to 9 was used as a positive electrode, and a metal lithium plate was used as a negative electrode, and the nickel-cobalt-manganese positive electrode material and the metal lithium plate were respectively assembled into 9 button cells to perform a charge-discharge comparative test, and the test results were as follows:

table 1 shows specific discharge capacity test data of the positive electrode materials of the batteries obtained in examples 1 to 9 and the positive electrode material of the conventional battery

From table 1, it can be derived: by adopting the anode material as the anode and the metal lithium sheet as the cathode to assemble the button cell for charge-discharge comparative test, the initial discharge specific capacity can reach 198mAh/g under the multiplying power of 0.5C, the capacity retention rate can reach 98.7 percent after 100 charge-discharge cycles, while the initial discharge specific capacity of the common anode material is 183mAh/g, and the capacity retention rate is 96.2 percent after 100 charge-discharge cycles; therefore, the specific discharge capacity of the battery prepared from the nickel-cobalt-manganese anode material for the doped lithium ion battery is superior to that of the battery prepared from the conventional battery anode material.

According to the scheme of the invention, the Mg doping element is directly added in the coprecipitation process, so that the doping element can be uniformly distributed in the precursor particles, the modification effect of the doping element is effectively exerted, and the magnesium doping is beneficial to forming a good layered structure, enhancing the structural stability of the material and improving the cycle performance of the high-nickel ternary material. By controlling the synthesis process of the precursor, primary particles are directionally arranged to form a radial structure from inside to outside, and the precursor particles grow radially from inside to outside, so that the lithium salt is favorably diffused in the precursor particles in the sintering process for preparing the anode material, the reaction is more sufficient, the prepared ternary anode material can form a lithium ion diffusion channel from inside to outside, the radial structure is favorable for the extraction and the insertion of lithium ions, and the particle structure is more stable, so that the excellent electrochemical performance is shown.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.