阅读说明：本技术 一种单晶三元正极材料及其制备方法以及锂离子电池 (Single-crystal ternary cathode material, preparation method thereof and lithium ion battery ) 是由 同格拉格 刘丕录 吴江 于 2021-06-24 设计创作，主要内容包括：本发明提供了一种单晶三元正极材料的制备方法,包括以下步骤：A)将三元材料前驱体、锂源和添加剂混合后挤压,得到坯体；所述添加剂选自金属粉末和碳粉中的一种或多种,所述金属粉末选自金属钴粉、金属锰粉和金属镍粉中的一种或多种；B)用电弧放电对所述坯体底部点火进行自蔓延高温燃烧合成,冷却后得到中间体；C)将所述中间体依次进行破碎、整形、分级、焙烧和冷却,得到单晶三元正极材料。本发明提供的单晶三元材料制备方法工艺简单,制备成本较低,适合大规模工业化生产。(The invention provides a preparation method of a single crystal ternary cathode material, which comprises the following steps: A) mixing and extruding a ternary material precursor, a lithium source and an additive to obtain a blank; the additive is selected from one or more of metal powder and carbon powder, and the metal powder is selected from one or more of metal cobalt powder, metal manganese powder and metal nickel powder; B) igniting the bottom of the blank by using arc discharge to perform self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; C) and sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material. The preparation method of the single crystal ternary material provided by the invention is simple in process, low in preparation cost and suitable for large-scale industrial production.)

1. The preparation method of the single crystal ternary cathode material is characterized by comprising the following steps of:

A) mixing and extruding a ternary material precursor, a lithium source and an additive to obtain a blank;

the additive is selected from one or more of metal powder and carbon powder, and the metal powder is selected from one or more of metal cobalt powder, metal manganese powder and metal nickel powder;

B) igniting the bottom of the blank by using arc discharge to perform self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate;

C) and sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material.

2. The method of claim 1, wherein the ternary material precursor is selected from Ni_xCo_yMn_1-x-y(OH)₂Wherein 0.3<x<1，0<y<0.4。

3. The method of claim 1, wherein the lithium source is selected from one or more of lithium carbonate, lithium hydroxide, and lithium fluoride.

4. The preparation method according to claim 1, wherein the carbon powder is selected from one or more of carbon black, acetylene black, graphite powder, wood carbon powder and activated carbon.

5. The method of claim 1, wherein the additive is selected from the group consisting of metal powder and carbon powder.

6. The preparation method according to claim 4, wherein the molar ratio of the ternary material precursor to the lithium source to the metal powder to the carbon powder is 1: (1-1.1): (0.001-0.05): (0.01-0.05).

7. The preparation method according to claim 1, wherein the self-propagating high-temperature combustion synthesis ignition mode is arc discharge ignition, the discharge voltage of the arc discharge is 1-380V, and the discharge time is 1-60 s.

8. The preparation method according to claim 1, wherein the roasting temperature is 500-900 ℃ and the roasting time is 2-48 h.

9. A single crystal ternary cathode material prepared by the preparation method of any one of claims 1 to 8.

10. A lithium ion battery is characterized by comprising the single crystal ternary cathode material prepared by the preparation method of any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a single crystal ternary cathode material, a preparation method thereof and a lithium ion battery.

Background

Currently commercialized lithium ion battery positive electrode materials include lithium cobaltate, lithium manganate, lithium iron phosphate, and nickel cobalt manganese ternary positive electrode materials. Compared with other anode materials, the nickel-cobalt-manganese ternary anode material has higher discharge specific capacity, higher cycle performance and rate capability, and is particularly suitable to be used as an anode material of a high-energy-density lithium ion battery. The common ternary material is in a polycrystalline spherical shape, and is easily broken into a plurality of fine particles in the pole piece compaction process, so that the side reactions in the charging and discharging processes of the lithium ion battery are increased, and the cycle performance is reduced.

The existing preparation process of the nickel-cobalt-manganese ternary cathode material with the single crystal morphology mainly focuses on the aspects of precursor preparation by a hydrothermal method, sintering temperature increase, fluxing agent addition, multiple sintering, particle crushing and the like, has large unit energy consumption, and is not beneficial to large-scale application of the single crystal ternary material. For example, chinese patent publication No. CN111600010A discloses a method for preparing large single crystals of ternary materials, which comprises mixing the main raw materials of ternary materials, precipitant, template agent and fluxing agent in deionized water according to a certain proportion, hydrothermal reaction in a reaction kettle to obtain ternary material precursors, and then adding a lithium source to calcine at high temperature to obtain single crystal particles. However, this method is limited by the volume of the reaction kettle, and the energy consumption per ton of product is large and large-scale production is difficult to realize. For example, Chinese patent with publication number CN110923801A discloses a preparation method and application of a single crystal ternary material, wherein a fluxing agent is added in the process of preparing a precursor, after being uniformly mixed, the precursor is roasted for one time in an oxygen atmosphere, a roasted product is crushed and then washed by water to remove the fluxing agent, and the single crystal ternary precursor is obtained after drying; and mixing the single crystal ternary precursor with a lithium source, and carrying out secondary roasting in an oxygen-containing atmosphere to obtain the single crystal ternary material. The method consumes a large amount of water resources when removing the fluxing agent, and the single crystal ternary material can be obtained through multiple times of roasting, thereby not meeting the requirements of energy conservation and environmental protection.

Disclosure of Invention

In view of this, the technical problem to be solved by the present invention is to provide a single crystal ternary cathode material, a preparation method thereof, and a lithium ion battery.

The invention provides a preparation method of a single crystal ternary cathode material, which comprises the following steps:

A) mixing and extruding a ternary material precursor, a lithium source and an additive to obtain a blank;

the additive is selected from one or more of metal powder and carbon powder, and the metal powder is selected from one or more of metal cobalt powder, metal manganese powder and metal nickel powder;

B) igniting the bottom of the blank by using arc discharge to perform self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate;

C) and sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material.

Preferably, the ternary material precursor is selected from Ni_xCo_yMn_1-x-y(OH)₂Wherein 0.3<x<1， 0<y<0.4。

Preferably, the lithium source is selected from one or more of lithium carbonate, lithium hydroxide and lithium fluoride.

Preferably, the carbon powder is selected from one or more of carbon black, acetylene black, graphite powder, charcoal powder and activated carbon.

Preferably, the additive is selected from metal powder and carbon powder.

Preferably, the molar ratio of the ternary material precursor to the lithium source to the metal powder to the carbon powder is 1: (1-1.1): (0.001-0.05): (0.01-0.05).

Preferably, the self-propagating high-temperature combustion synthesis ignition mode is arc discharge ignition, the discharge voltage of the arc discharge is 1-380V, and the discharge time is 1-60 s.

Preferably, the roasting temperature is 500-900 ℃, and the roasting time is 2-48 h.

The invention also provides the single crystal ternary cathode material prepared by the preparation method.

The invention also provides a lithium ion battery which comprises the single crystal ternary cathode material prepared by the preparation method.

Compared with the prior art, the invention provides a preparation method of a single crystal ternary cathode material, which comprises the following steps: A) mixing and extruding a ternary material precursor, a lithium source and an additive to obtain a blank; the additive is selected from one or more of metal powder and carbon powder, and the metal powder is selected from one or more of metal cobalt powder, metal manganese powder and metal nickel powder; B) igniting the bottom of the blank by using arc discharge to perform self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; C) and sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material. According to the invention, the ternary material precursor, the lithium source and the additive are uniformly mixed and extruded into the high-density green body, so that the capacity of the reaction furnace in unit volume can be improved. And (2) igniting the bottom of the blank by using electric arc discharge, wherein the electric arc discharge can generate instantaneous high temperature of 3000 ℃ at a discharge point at the bottom of the blank, the instantaneous high temperature can ignite the metal powder and carbon powder in the blank, the blank generates a self-propagating high-temperature combustion reaction, and the precursor and the lithium salt react at high temperature to obtain an intermediate of the single crystal ternary material. And crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material. The intermediate is prepared by utilizing the heat generated by burning the metal powder and the carbon powder, so that the external high-temperature environment is not required, and the energy consumption required by the production of a large amount of anode materials is saved. The temperature is lower when the intermediate is roasted, the roasting time is short, and the energy consumption required by production is saved again. The preparation method of the single crystal ternary material provided by the invention is simple in process, low in preparation cost and suitable for large-scale industrial production.

Drawings

FIG. 1 is an electron scan photograph of an intermediate in example 1 of the present invention;

fig. 2 is an electron scanning photograph of a single crystal ternary cathode material in example 1 of the present invention.

Detailed Description

The invention provides a preparation method of a single crystal ternary cathode material, which comprises the following steps:

A) mixing and extruding a ternary material precursor, a lithium source and an additive to obtain a blank;

the additive is selected from one or more of metal powder and carbon powder, and the metal powder is selected from one or more of metal cobalt powder, metal manganese powder and metal nickel powder;

B) igniting the bottom of the blank by using arc discharge to perform self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate;

C) and sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material.

Firstly, uniformly mixing a ternary material precursor, a lithium source and an additive, and then putting the mixture into a die for extrusion to obtain a blank.

Wherein the ternary material precursor is selected from Ni_xCo_yMn_1-x-y(OH)₂Wherein 0.3<x<1， 0<y<0.4。

The lithium source is selected from one or more of lithium carbonate, lithium hydroxide and lithium fluoride.

The carbon powder is selected from one or more of carbon black, acetylene black, graphite powder, wood carbon powder and activated carbon. Preferably, the carbon powder is selected from one or more of carbon black, acetylene black and activated carbon.

In some embodiments of the invention, the additive is selected from the group consisting of metal powders and carbon powders.

The molar ratio of the ternary material precursor to the lithium source to the metal powder to the carbon powder is 1: (1-1.1): (0.001-0.05): (0.01 to 0.05), preferably 1: (1-1.05): (0.002-0.005): (0.01-0.03).

And then, putting the pressed blank into a reaction furnace, igniting the bottom of the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate.

In the invention, the self-propagating high-temperature combustion synthesis ignition mode is arc discharge ignition, the discharge voltage of the arc discharge is 1-380V, and the discharge time is 1-60 s. Preferably, the discharge voltage of the arc discharge is 3-220V, and the discharge time is 5-30 s. More preferably, the discharge voltage of the arc discharge is 12-36V, and the discharge time is 10-20 s.

And after obtaining the intermediate, sequentially crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material.

Wherein the roasting temperature is 500-900 ℃, and the roasting time is 2-48 h. More preferably, the roasting temperature is 550-750 ℃, and the roasting time is 4-10 h.

The invention also provides the single crystal ternary cathode material prepared by the preparation method.

The invention also provides a lithium ion battery which comprises the single crystal ternary cathode material prepared by the preparation method.

According to the invention, the ternary material precursor, the lithium source and the additive are uniformly mixed and extruded into the high-density green body, so that the capacity of the reaction furnace in unit volume can be improved. And (2) igniting the bottom of the blank by using electric arc discharge, wherein the electric arc discharge can generate instantaneous high temperature of 3000 ℃ at a discharge point at the bottom of the blank, the instantaneous high temperature can ignite the metal powder and carbon powder in the blank, the blank generates a self-propagating high-temperature combustion reaction, and the precursor and the lithium salt react at high temperature to obtain an intermediate of the single crystal ternary material. And crushing, shaping, grading, roasting and cooling the intermediate to obtain the single crystal ternary cathode material. The intermediate is prepared by utilizing the heat generated by burning the metal powder and the carbon powder, so that the external high-temperature environment is not required, and the energy consumption required by the production of a large amount of anode materials is saved. The temperature is lower when the intermediate is roasted, the roasting time is short, and the energy consumption required by production is saved again. The preparation method of the single crystal ternary material provided by the invention is simple in process, low in preparation cost and suitable for large-scale industrial production.

For further understanding of the present invention, the single crystal ternary cathode material, the preparation method thereof and the lithium ion battery provided by the present invention are described below with reference to the following examples, and the scope of the present invention is not limited by the following examples.

Example 1

A) According to a molar ratio of 1.04: 1: 0.01: 0.01 weight of lithium hydroxide and Ni_0.5Co_0.3Mn_0.2(OH)₂Gold, goldThe Mn powder and the carbon black are uniformly mixed and then are placed into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 24V, and the discharge time was 15 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.3Mn_0.2O₂A ternary positive electrode material; the roasting temperature is 600 ℃, and the roasting time is 8 hours.

Referring to FIGS. 1-2, FIG. 1 is an electron scan photograph of the intermediate of example 1. As can be seen from fig. 1, after the self-propagating reaction, the nickel-cobalt-manganese ternary positive electrode material intermediate with high compactness is obtained. Fig. 2 is an electron scanning photograph of the single crystal ternary cathode material of example 1. As can be seen from FIG. 2, the prepared nickel-cobalt-manganese ternary cathode material has a single crystal morphology.

Example 2

A) According to a molar ratio of 1.02: 1: 0.01: 0.02 weight of lithium hydroxide and Ni_0.5Co_0.2Mn_0.3(OH)₂Metal Ni powder and carbon black are mixed evenly and then put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 36V, and the discharge time was 8 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.2Mn_0.3O₂A ternary positive electrode material; the roasting temperature is 650 ℃, and the roasting time is 6 h.

Example 3

A) According to a molar ratio of 1.01: 1: 0.005: 0.02 weight lithium carbonate, Ni_0.6Co_0.2Mn_0.2(OH)₂Metal Co powder and acetylene black are mixed evenly and then put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 220V, and the discharge time was 2 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.6Co_0.2Mn_0.2O₂A ternary positive electrode material; the roasting temperature is 550 ℃, and the roasting time is 12 hours.

Example 4

A) According to a molar ratio of 1.05: 1: 0.008: 0.01 weight of lithium hydroxide and Ni_0.8Co_0.1Mn_0.1(OH)₂Metal Mn powder and active carbon, evenly mixing, putting into a die, and extruding into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 24V, and the discharge time was 12 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.8Co_0.1Mn_0.1O₂A ternary positive electrode material; the roasting temperature is 630 ℃, and the roasting time is 10 hours.

Example 5

A) According to a molar ratio of 1.03: 1: 0.002: 0.015 weight of lithium carbonate and Ni_0.8Co_0.1Mn_0.1(OH)₂Metal Mn powder and graphite powder are mixed evenly and then put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 380V, and the discharge time was 2 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi₀₈Co_0.1Mn_0.1O₂A ternary positive electrode material; the roasting temperature is 680 ℃, and the roasting time is 5 h.

Example 6

A) According to a molar ratio of 1.02: 1: 0.03: 0.02 weight of lithium hydroxide and Ni_0.3Co_0.3Mn_0.4(OH)₂Metal Ni powder and charcoal powder are mixed evenly and then put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 24V, and the discharge time was 10 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.3Co_0.3Mn_0.4O₂A ternary positive electrode material; the roasting temperature is 600 ℃, and the roasting time is 8 hours.

Example 7

A) According to a molar ratio of 1.05: 1: 0.04: 0.05 weight of lithium carbonate and Ni_0.5Co_0.3Mn₀₂(OH)₂Metal Mn powder and carbon black are evenly mixed and then are placed into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 36V, and the discharge time was 10 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.3Mn_0.2O₂A ternary positive electrode material; the roasting temperature is 800 ℃, and the roasting time is 5 h.

Example 8

A) According to a molar ratio of 1.04: 1: 0.01: 0.01 weight of lithium hydroxide and Ni_0.5Co_0.3Mn_0.2(OH)₂Metal Mn powder and carbon black are evenly mixed and then are placed into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 24V, and the discharge time was 25 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.2Mn_0.3O₂A ternary positive electrode material; the roasting temperature is 680 ℃, and the roasting time is 15 h.

Example 9

A) According to a molar ratio of 1.01: 1: 0.003: 0.008 weigh lithium carbonate and Ni_0.6Co_0.2Mn_0.2(OH)₂Metal Mn powder and acetylene black are mixed evenly and then put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 24V, and the discharge time was 20 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.2Mn_0.3O₂A ternary positive electrode material; the roasting temperature is 580 ℃, and the roasting time is 10 hours.

Example 10

A) According to a molar ratio of 1: 1: 0.005: 0.02 weight lithium carbonate, Ni_0.5Co_0.3Mn_0.2(OH)₂The metal Co powder and the active carbon are mixed evenly and then are put into a die to be extruded into a blank.

B) Then putting the pressed blank into a reaction furnace, igniting the blank by using electric arc discharge to carry out self-propagating high-temperature combustion synthesis, and cooling to obtain an intermediate; the discharge voltage of the arc discharge was 36V, and the discharge time was 6 s.

C) Crushing, shaping, roasting and cooling the intermediate to obtain the single crystal LiNi_0.5Co_0.3Mn_0.2O₂A ternary positive electrode material; the roasting temperature is 700 ℃, and the roasting time is 8 h.

Comparative example 1

According to a molar ratio (Ni + Co + Mn): k: mg is 30: 2: 1 weigh Ni_0.5Co_0.3Mn_0.2(OH)₂Adding KCl and MgCl into a high-speed mixer, uniformly mixing, sintering at 650 ℃ for 8h in an oxygen atmosphere, crushing, washing with water, and drying to obtain a single crystal ternary precursor; mixing the molar ratio (Ni + Co + Mn): li-1: 1.05 weighing the single crystal ternary precursor and LiOH, mixing uniformly, and oxidizingSecondary sintering is carried out for 16 hours at 800 ℃ under the gas atmosphere; cooling, dissociating and sieving to obtain single crystal LiNi_0.5Co_0.3Mn_0.2O₂A ternary positive electrode material.

The electric energy consumption and the water consumption of each ton of single crystal ternary cathode material of the examples 1 to 10 and the comparative example 1 are counted. As shown in table 1, according to the preparation method of the present invention, energy consumption in material production can be reduced, production cycle can be shortened, and production cost of the single crystal ternary cathode material can be significantly reduced.

TABLE 1 COMPARATIVE TABLE OF ELECTRICITY AND WATER CONSUMPTION FOR EXAMPLES 1-10 AND COMPARATIVE EXAMPLE 1

The lithium ion battery positive pole piece prepared by the embodiments 1-10 and the comparative example 1 is tested for the compaction density, and the results are shown in table 2.

TABLE 2 comparison of compacted densities of examples 1-10 and comparative example 1

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.