阅读说明：本技术 锂离子电池三元正极材料表面包覆碳的处理方法及燃烧装置 (Processing method for coating carbon on surface of ternary positive electrode material of lithium ion battery and combustion device ) 是由 王中旭 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种锂离子电池三元正极材料表面包覆碳的处理方法及燃烧装置,该处理方法为：将碳源置于乙醇和丙酮的混合溶液,磁力搅拌后过滤,获得黑色溶液；将氢氧化锂(LiOH)、柠檬酸溶于所述黑色溶液中,搅拌均匀后烘干,获得第一黑色粉末；将所述第一黑色粉末、NCM正极材料粉体以及PVA混合,球磨后,获得第二黑色粉末；将所述第二黑色粉末在燃烧装置内经火焰燃烧法,即可得到表面包覆碳的NCM三元正极材料粉体。本发明所制备的三元NCM正极材料具有良好的循环稳定性,采用火焰燃烧法,快速固化腐殖酸,既形成了有效的碳包覆,又通过臭氧的强氧化作用防止烧结过程中包覆碳对NCM表面氧的夺取,有效抑制了晶格氧的逸失。(The invention discloses a processing method and a combustion device for coating carbon on the surface of a ternary cathode material of a lithium ion battery, wherein the processing method comprises the following steps: placing a carbon source in a mixed solution of ethanol and acetone, magnetically stirring, and filtering to obtain a black solution; dissolving lithium hydroxide (LiOH) and citric acid in the black solution, uniformly stirring and drying to obtain first black powder; mixing the first black powder, NCM positive electrode material powder and PVA, and performing ball milling to obtain second black powder; and (3) carrying out flame combustion on the second black powder in a combustion device to obtain the NCM ternary cathode material powder with the carbon-coated surface. The ternary NCM cathode material prepared by the invention has good circulation stability, and humic acid is rapidly solidified by adopting a flame combustion method, so that effective carbon coating is formed, the capture of coating carbon to NCM surface oxygen in the sintering process is prevented by the strong oxidation effect of ozone, and the escape of lattice oxygen is effectively inhibited.)

1. A processing method for coating carbon on the surface of a ternary cathode material of a lithium ion battery is characterized by comprising the following steps:

placing a carbon source in a mixed solution of ethanol and acetone, magnetically stirring, and filtering to obtain a black solution;

dissolving lithium hydroxide (LiOH) and citric acid in the black solution, uniformly stirring and drying to obtain first black powder;

mixing the first black powder, NCM positive electrode material powder and PVA, and performing ball milling to obtain second black powder;

and (3) carrying out flame combustion on the second black powder in a combustion device to obtain the NCM ternary cathode material powder with the carbon-coated surface.

2. The treatment method for coating carbon on the surface of the ternary cathode material of the lithium ion battery according to claim 1, wherein humic acid is placed in a mixed solution of ethanol and acetone, and is filtered after magnetic stirring to obtain a black solution, and specifically comprises the following steps:

step 1.1, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

step 1.2, preparing a mixed solution of ethanol and acetone according to a volume ratio of 2-5: 1;

step 1.3, adding humic acid into the mixed solution, wherein the adding proportion is that 200-300g of humic acid is added into every 100ml of solution;

step 1.4, stirring for 30-60 minutes at 30-50 ℃, wherein the stirring speed is 500-600 r/min;

and step 1.5, filtering to obtain a black solution.

3. The treatment method for coating carbon on the surface of the ternary cathode material of the lithium ion battery according to claim 1 or 2, wherein lithium hydroxide (LiOH) and citric acid are dissolved in the black solution, uniformly stirred and dried to obtain a first black powder, and specifically:

step 2.1, adding LiOH into the black solution;

step 2.2, adding 30-50 g of LiOH into each 100ml of black solution according to the proportion;

step 2.3, stirring at a rotating speed of 500-600 r/min for 30-60 min;

step 2.4, adding citric acid into the liquid, and adjusting the pH value to be 1-2.5;

and 2.5, drying the liquid at 120-150 ℃ to obtain first black powder.

4. The processing method for coating carbon on the surface of the ternary cathode material of the lithium ion battery according to claim 3, wherein the first black powder, the NCM cathode material powder and PVA are mixed and ball-milled to obtain a second black powder, and specifically comprises the following steps:

3.1, mixing the first black powder and NCM positive electrode material powder according to the mass ratio of 1: 50-75;

step 3.2, dripping PVA into the powder obtained in the step 3.1, wherein the mass ratio of the PVA is 0.5-1%;

and 3.3, ball-milling the mixture in a planetary ball mill for 4-6 hours at the rotating speed of the ball mill of 150-200 r/min to obtain second black powder.

5. The method for processing the carbon-coated surface of the ternary cathode material of the lithium ion battery according to claim 4, wherein the second black powder is subjected to a flame combustion method in a combustion device to obtain the carbon-coated NCM ternary cathode material powder, and the method specifically comprises the following steps:

step 4.1, carrying out flame combustion on the second black powder at 800-1000 ℃ in a combustion device;

step 4.2, the feeding speed of the second black powder in the flame is 5-7 g/cm 2;

4.3, setting the flame combustion distance to be 10-20 cm;

4.4, controlling the flowing time of the powder in the flame to be 2-3 seconds through airflow at the bottom of the flame;

and 4.5, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

6. The processing method of the surface coating carbon of the ternary cathode material of the lithium ion battery according to claim 5, wherein the combustion device comprises a cylinder, a feeding screening mechanism, a combustion mechanism, a strong ozone oxidation mechanism and a material collecting disc, the feeding screening mechanism is located on the upper side of the cylinder and used for feeding the second black powder into the combustion mechanism, the combustion mechanism is arranged in the middle of the cylinder and used for carrying out short-time high-temperature flame combustion on the fed second powder to solidify the surface coating to form crystalline carbon, the strong ozone oxidation mechanism is arranged on the lower side of the cylinder and used for upwards floating and dropping the second black powder, and the material collecting disc is arranged at the bottom of the cylinder and used for collecting the carbon-coated high-nickel NCM cathode material.

7. The method for processing the surface of the ternary cathode material of the lithium ion battery coated with carbon according to claim 6, wherein the feeding and screening mechanism comprises a feeding screen, a vibration compression spring and a vibration motor, wherein two sides of the feeding screen are arranged in the cylinder through the vibration compression spring, and the vibration motor is arranged outside the cylinder and is connected with one vibration compression spring.

8. The method for treating the surface of the ternary cathode material of the lithium ion battery with carbon coating is characterized in that the combustion mechanism comprises a circular nozzle and a fuel gas source, the circular nozzle is an annular disc, a plurality of nozzles are uniformly arranged on the annular disc, and the circular nozzle is connected with the inner wall of the cylinder and is communicated with the fuel gas source outside the cylinder.

9. The processing method for coating carbon on the surface of the ternary cathode material of the lithium ion battery according to claim 8, wherein the ozone strong oxidation mechanism comprises a ground pole annular steel pipe, a high voltage pole annular steel pipe, an annular insulating member, an oxygen gas source and an alternating current power source, the ground pole annular steel pipe is positioned on the upper side of the high voltage pole annular steel pipe and is communicated with the oxygen gas source, an enamel layer is arranged on the outer wall of the ground pole annular steel pipe, the annular insulating member is arranged on the lower side of the high voltage pole annular steel pipe, and the annular insulating member is grounded and is loaded on the alternating current power source to form an electric field between the pole annular steel pipe and the high voltage pole annular steel pipe.

10. The method for processing the surface of the ternary cathode material of the lithium ion battery coated with carbon according to claim 9, wherein a K-type thermocouple is arranged on one side of the cylinder in a penetrating manner and is positioned above the circular nozzle.

Technical Field

The invention belongs to the technical field of new energy material preparation methods, and particularly relates to a treatment method for coating carbon on the surface of a ternary positive electrode material of a lithium ion battery and a combustion device.

Background

The lithium ion battery has the advantages of working voltage, energy density, high safety and the like, and is widely applied to the fields of movable electronic equipment, electric automobiles, medical supplies, aerospace, national defense and the like. The anode material is a core material for forming the lithium ion battery, and the currently commercialized anode material mainly comprises LiFePO with an olivine structure₄Layered structured LiCoO₂And the ternary system LiNi_xMn_yCo_zO₂(x+y+z＝1，NCM)。

The NCM has the synergistic effect of Ni, Mn and Co, shows the advantages of high discharge specific capacity, simple synthesis process and low cost, and has good application prospect. However, the electrochemical performance of the NCM cathode material is seriously influenced due to the problems of serious Li/Ni mixed discharge, irreversible phase change, surface residual lithium, side reaction between the material surface and electrolyte and the like. Researches show that the surface coating of carbon is one of effective modes for enhancing the conductivity of the cathode material, reducing the surface residual lithium, reducing the surface irreversible phase change and inhibiting the side reaction of the electrolyte and the surface. The carbon-based coating layer comprises activated carbon, graphite, graphene and the like, so that impedance can be reduced, capacity can be improved, a three-dimensional conductive network can be formed on the surface of the anode material, and electrode dynamics is greatly improved.

However, during the sintering preparation of the NCM material, there is usually serious lattice oxygen loss, so that the NCM cathode material needs to be prepared by sintering in a pure oxygen environment. During the carbon coating of the NCM, the carbon material provides a reducing environment that promotes the escape of oxygen from the material lattice.

Disclosure of Invention

In view of the above, the main objective of the present invention is to provide a method for treating carbon coating on the surface of a ternary cathode material of a lithium ion battery and a combustion apparatus.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

the embodiment of the invention provides a processing method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

placing a carbon source in a mixed solution of ethanol and acetone, magnetically stirring, and filtering to obtain a black solution;

dissolving lithium hydroxide (LiOH) and citric acid in the black solution, uniformly stirring and drying to obtain first black powder;

mixing the first black powder, NCM positive electrode material powder and PVA, and performing ball milling to obtain second black powder;

and (3) carrying out flame combustion on the second black powder in a combustion device to obtain the NCM ternary cathode material powder with the carbon-coated surface.

In the above scheme, the humic acid is placed in a mixed solution of ethanol and acetone, and the mixed solution is filtered after magnetic stirring to obtain a black solution, specifically:

step 1.1, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

step 1.2, preparing a mixed solution of ethanol and acetone according to a volume ratio of 2-5: 1;

step 1.3, adding humic acid into the mixed solution, wherein the adding proportion is that 200-300g of humic acid is added into every 100ml of solution;

step 1.4, stirring for 30-60 minutes at 30-50 ℃, wherein the stirring speed is 500-600 r/min;

and step 1.5, filtering to obtain a black solution.

In the above scheme, the lithium hydroxide (LiOH) and citric acid are dissolved in the black solution, and are uniformly stirred and then dried to obtain a first black powder, specifically:

step 2.1, adding LiOH into the black solution;

step 2.2, adding 30-50 g of LiOH into each 100ml of black solution according to the proportion;

step 2.3, stirring at a rotating speed of 500-600 r/min for 30-60 min;

step 2.4, adding citric acid into the liquid, and adjusting the pH value to be 1-2.5;

and 2.5, drying the liquid at 120-150 ℃ to obtain first black powder.

In the above scheme, the first black powder, the NCM positive electrode material powder and PVA are mixed and ball-milled to obtain a second black powder, specifically:

3.1, mixing the first black powder and NCM positive electrode material powder according to the mass ratio of 1: 50-75;

step 3.2, dripping PVA into the powder obtained in the step 3.1, wherein the mass ratio of the PVA is 0.5-1%;

and 3.3, ball-milling the mixture in a planetary ball mill for 4-6 hours at the rotating speed of the ball mill of 150-200 r/min to obtain second black powder.

In the above scheme, the second black powder is subjected to a flame combustion method in a combustion device to obtain a carbon-coated NCM ternary positive electrode material powder, specifically:

step 4.1, carrying out flame combustion on the second black powder at 800-1000 ℃ in a combustion device;

step 4.2, the feeding speed of the second black powder in the flame is 5-7 g/cm 2;

4.3, setting the flame combustion distance to be 10-20 cm;

4.4, controlling the flowing time of the powder in the flame to be 2-3 seconds through airflow at the bottom of the flame;

and 4.5, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

In the above scheme, burner includes barrel, reinforced sieve material mechanism, combustion mechanism, the strong oxidation mechanism of ozone, receives the charging tray, reinforced sieve material mechanism is located the barrel upside for put in second black powder to combustion mechanism, combustion mechanism sets up the intermediate position at the barrel, is used for carrying out short-term high temperature flame burning solidification surface cladding thing formation crystalline state carbon to the second powder of putting in, the strong oxidation mechanism of ozone sets up the downside at the barrel for upwards urge to float whereabouts second black powder, receive the charging tray setting in the bottom of barrel for collect the high nickel NCM cathode material of carbon cladding.

In the above scheme, reinforced sieve material mechanism is including reinforced screen cloth, vibration compression spring, vibrating motor, the both sides of reinforced screen cloth are passed through vibration compression spring and are set up in the barrel, vibrating motor sets up outside the barrel and with one of them vibration compression spring connection.

In the above scheme, the combustion mechanism comprises a circular nozzle and a fuel gas source, the circular nozzle is an annular disc, a plurality of nozzles are uniformly distributed on the annular disc, and the circular nozzle is connected with the inner wall of the cylinder and communicated with the fuel gas source outside the cylinder.

In the above scheme, ozone strong oxidation mechanism includes utmost point annular steel pipe, high-voltage pole annular steel pipe, annular insulating part, oxygen air supply, alternating current power supply, utmost point annular steel pipe is located the upside of utmost point annular steel pipe to with oxygen air supply intercommunication, be provided with enamel layer on the outer wall of utmost point annular steel pipe, the downside of high-voltage pole annular steel pipe sets up annular insulating part, ground connection on the annular insulating part to the loading is used for forming the electric field on alternating current power supply between utmost point annular steel pipe, high-voltage pole annular steel pipe.

In the scheme, a K-type thermocouple is arranged on one side of the cylinder in a penetrating mode and is located above the circular nozzle.

Compared with the prior art, the ternary NCM cathode material prepared by the invention has good circulation stability, humic acid is rapidly solidified by adopting a flame combustion method, effective carbon coating is formed, the capture of carbon coated on the surface of the NCM in the sintering process is prevented by the strong oxidation effect of ozone, and the escape of lattice oxygen is effectively inhibited.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a schematic view of a combustion apparatus according to the present invention;

FIG. 2 is a schematic view of the construction of the feed screen of the combustion apparatus of the present invention;

FIG. 3 is a schematic view of the construction of an annular nozzle of the combustion apparatus of the present invention;

FIG. 4 is a sectional view of the ozone strong oxidizing mechanism of the combustion apparatus 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 described in further detail below with reference to the accompanying drawings and 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 same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, the terms describing the positional relationships in the drawings are only for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, article, or apparatus that comprises the element.

The embodiment of the invention provides a processing method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

step 1, placing a carbon source in a mixed solution of ethanol and acetone, magnetically stirring, and filtering to obtain a black solution;

step 2, dissolving lithium hydroxide (LiOH) and citric acid in the black solution, uniformly stirring and drying to obtain first black powder;

step 3, mixing the first black powder, NCM positive electrode material powder and PVA, and performing ball milling to obtain second black powder;

and 4, carrying out flame combustion on the second black powder in a combustion device to obtain the NCM ternary cathode material powder with the carbon coated surface.

Specifically, step 1 specifically comprises:

step 1.1, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

step 1.2, preparing a mixed solution of ethanol and acetone according to a volume ratio of 2-5: 1;

step 1.3, adding humic acid into the mixed solution, wherein the adding proportion is that 200-300g of humic acid is added into every 100ml of solution;

step 1.4, stirring for 30-60 minutes at 30-50 ℃, wherein the stirring speed is 500-600 r/min;

and step 1.5, filtering to obtain a black solution.

The step 2 specifically comprises the following steps:

step 2.1, adding LiOH into the black solution;

step 2.2, adding 30-50 g of LiOH into each 100ml of black solution according to the proportion;

step 2.3, stirring at a rotating speed of 500-600 r/min for 30-60 min;

step 2.4, adding citric acid into the liquid, and adjusting the pH value to be 1-2.5;

and 2.5, drying the liquid at 120-150 ℃ to obtain first black powder.

The step 3 specifically comprises the following steps:

3.1, mixing the first black powder and NCM positive electrode material powder according to the mass ratio of 1: 50-75;

step 3.2, dripping PVA into the powder obtained in the step 3.1, wherein the mass ratio of the PVA is 0.5-1%;

and 3.3, ball-milling the mixture in a planetary ball mill for 4-6 hours at the rotating speed of the ball mill of 150-200 r/min to obtain second black powder.

The step 4 specifically comprises the following steps:

step 4.1, carrying out flame combustion on the second black powder at 800-1000 ℃ in a combustion device;

step 4.2, the feeding speed of the second black powder in the flame is 5-7 g/cm 2;

4.3, setting the flame combustion distance to be 10-20 cm;

4.4, controlling the flowing time of the powder in the flame to be 2-3 seconds through airflow at the bottom of the flame;

and 4.5, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

Example 1

The embodiment 1 of the invention provides a treatment method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

101, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

102, preparing a mixed solution of ethanol and acetone according to the volume ratio of 2: 1;

103, adding humic acid into the mixed solution, wherein the adding proportion is that 200g of humic acid is added into every 100ml of solution;

104, stirring for 30 minutes at 30 ℃, wherein the stirring speed is 500 r/min;

105, filtering to obtain a black solution;

106, adding LiOH into the black solution;

step 107, adding 30g of LiOH into each 100ml of black solution;

108, stirring for 30min at the rotating speed of 500 r/min;

step 109, adding citric acid into the liquid, and adjusting the pH value to 1;

step 110, drying the liquid at 120 ℃ to obtain first black powder;

111, mixing the first black powder and NCM positive electrode material powder according to a mass ratio of 1: 50;

112, dripping PVA into the powder obtained in the step 111, wherein the mass ratio of the PVA is 0.5%;

step 113, ball-milling the mixture in a planetary ball mill for 4 hours at the rotating speed of 150r/min to obtain second black powder;

step 114, burning the second black powder in a combustion device by flame at 800 ℃;

step 115, putting the second black powder into the flame at a speed of 5g/cm 2;

step 116, setting the flame burning distance at 10 cm;

step 117, controlling the flowing time of the powder in the flame to be 2 seconds through airflow at the bottom of the flame;

and step 118, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

Example 2

The embodiment 2 of the invention provides a treatment method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

101, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

102, preparing a mixed solution of ethanol and acetone according to the volume ratio of 5: 1;

103, adding humic acid into the mixed solution, wherein the adding proportion is that 300g of humic acid is added into every 100ml of solution;

104, stirring for 60 minutes at 50 ℃, wherein the stirring speed is 600 r/min;

105, filtering to obtain a black solution;

106, adding LiOH into the black solution;

step 107, adding 50g of LiOH into each 100ml of black solution;

108, stirring at the rotating speed of 600r/min for 60 min;

step 109, adding citric acid into the liquid, and adjusting the pH value to 2.5;

step 110, drying the liquid at 150 ℃ to obtain first black powder;

111, mixing the first black powder and NCM positive electrode material powder according to a mass ratio of 1: 75;

112, dripping PVA into the powder obtained in the step 111, wherein the mass ratio of the PVA is 1%;

step 113, ball-milling the mixture in a planetary ball mill for 6 hours at the rotating speed of 200r/min to obtain second black powder;

step 114, burning the second black powder in a combustion device by flame of 1000 ℃;

step 115, putting the second black powder into the flame at a speed of 7g/cm 2;

step 116, setting the flame burning distance at 20 cm;

step 117, controlling the flowing time of the powder in the flame to be 3 seconds through airflow at the bottom of the flame;

and step 118, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

Example 3

The embodiment 3 of the invention provides a treatment method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

101, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

102, preparing a mixed solution of ethanol and acetone according to the volume ratio of 3: 1;

103, adding humic acid into the mixed solution, wherein the adding proportion is that 250g of humic acid is added into every 100ml of solution;

104, stirring for 30-60 minutes at 40 ℃, wherein the stirring speed is 550 r/min;

105, filtering to obtain a black solution;

106, adding LiOH into the black solution;

step 107, adding 40g of LiOH into each 100ml of black solution;

108, stirring for 45min at the rotating speed of 550 r/min;

step 109, adding citric acid into the liquid, and adjusting the pH value to 2;

step 110, drying the liquid at 135 ℃ to obtain first black powder;

111, mixing the first black powder and NCM positive electrode material powder according to a mass ratio of 1: 60;

112, dripping PVA into the powder obtained in the step 111, wherein the mass ratio of the PVA is 0.7%;

step 113, ball-milling the mixture in a planetary ball mill for 5 hours at the rotating speed of 175r/min to obtain second black powder;

step 114, subjecting the second black powder to 900-degree flame combustion in a combustion device;

step 115, putting the second black powder into the flame at a speed of 6g/cm 2;

step 116, setting the flame burning distance at 15 cm;

step 117, controlling the flowing time of the powder in the flame to be 2.5 seconds through airflow at the bottom of the flame;

and step 118, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

Example 4

The embodiment 4 of the invention provides a treatment method for coating carbon on the surface of a ternary cathode material of a lithium ion battery, which comprises the following steps:

101, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

102, preparing a mixed solution of ethanol and acetone according to the volume ratio of 4: 1;

103, adding the humic acid into the mixed solution, wherein the adding proportion is that 280g of the humic acid is added into every 100ml of the solution;

104, stirring for 55 minutes at 35 ℃, wherein the stirring speed is 580 r/min;

105, filtering to obtain a black solution;

106, adding LiOH into the black solution;

107, adding 47g of LiOH into each 100ml of black solution;

108, stirring for 45min at the rotating speed of 580 r/min;

step 109, adding citric acid into the liquid, and adjusting the pH value to 1.5;

step 110, drying the liquid at 140 ℃ to obtain first black powder;

111, mixing the first black powder and NCM positive electrode material powder according to a mass ratio of 1: 65;

112, dripping PVA into the powder obtained in the step 111, wherein the mass ratio of the PVA is 0.7%;

step 113, ball-milling the mixture in a planetary ball mill for 5.5 hours at the rotating speed of the ball mill of 170r/min to obtain second black powder;

step 114, subjecting the second black powder to 820-degree flame combustion in a combustion device;

step 115, putting the second black powder into the flame at a speed of 5.5g/cm 2;

step 116, setting the flame burning distance at 15 cm;

step 117, controlling the flowing time of the powder in the flame to be 2 seconds through airflow at the bottom of the flame;

and step 118, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

Example 5

Embodiment 5 of the present invention provides a method for treating a carbon-coated surface of a ternary positive electrode material for a lithium ion battery, the method comprising:

101, adopting humic acid as a carbon source, wherein the purity requirement is analytically pure AR;

102, preparing a mixed solution of ethanol and acetone according to the volume ratio of 5: 1;

103, adding humic acid into the mixed solution, wherein the adding proportion is that 200g of humic acid is added into every 100ml of solution;

104, stirring for 30 minutes at 50 ℃, wherein the stirring speed is 500 r/min;

105, filtering to obtain a black solution;

106, adding LiOH into the black solution;

step 107, adding 50g of LiOH into each 100ml of black solution;

108, stirring at the rotating speed of 500r/min for 60 min;

step 109, adding citric acid into the liquid, and adjusting the pH value to 1;

step 110, drying the liquid at 150 ℃ to obtain first black powder;

111, mixing the first black powder and NCM positive electrode material powder according to a mass ratio of 1: 50;

112, dripping PVA into the powder obtained in the step 111, wherein the mass ratio of the PVA is 1%;

step 113, ball-milling the mixture in a planetary ball mill for 4 hours at the rotating speed of 200r/min to obtain second black powder;

step 114, burning the second black powder in a combustion device by flame at 800 ℃;

step 115, putting the second black powder into the flame at a speed of 7g/cm 2;

step 116, setting the flame burning distance at 10 cm;

step 117, controlling the flowing time of the powder in the flame to be 3 seconds through airflow at the bottom of the flame;

and step 118, cooling to room temperature, grinding, and sieving with a 200-mesh sieve to obtain the high-performance lithium ion battery NCM ternary cathode material powder with carbon coated on the surface.

In the preparation method, the reaction product of humic acid and LiOH is used as a lithium-containing carbon source and is directly mixed with the NCM integral material powder, and then the mixture is cured by flame combustion to form the high-performance lithium ion battery NCM ternary cathode material with carbon coated on the surface.

In the preparation method, the flame combustion method is adopted to quickly solidify the humic acid, so that effective carbon coating is formed, the coated carbon is prevented from capturing oxygen on the surface of NCM in the sintering process, and the escape of lattice oxygen is effectively inhibited.

The ternary NCM positive electrode material of the lithium ion battery prepared by the preparation method has the specific capacity of 180mAh/g, the cycle retention rate of 100 circles can reach more than 95 percent, and the ternary NCM positive electrode material has great economic and social benefits.

As shown in fig. 1, the combustion apparatus includes barrel 1, reinforced sieve material mechanism 2, combustion mechanism 3, ozone strong oxidation mechanism 4, receipts charging tray 5, reinforced sieve material mechanism 2 is located barrel 1 upside for put in the second black powder to combustion mechanism 3, combustion mechanism 3 sets up the intermediate position at barrel 1, is used for carrying out short-term high temperature flame burning solidification surface coating thing formation crystalline state carbon to the second powder of putting in, ozone strong oxidation mechanism 4 sets up the downside at barrel 1 for upwards urge to float and fall the second black powder, it sets up in the bottom of barrel 1 to receive charging tray 5, is used for collecting the high nickel NCM positive pole material of carbon cladding.

The feeding and screening mechanism 2 comprises a feeding screen 21, vibrating compression springs 22 and a vibrating motor 23, wherein two sides of the feeding screen 21 are arranged in the cylinder 1 through the vibrating compression springs 22, and the vibrating motor 23 is arranged outside the cylinder 1 and is connected with one vibrating compression spring 22.

The barrel body 1 is made of high-temperature-resistant metal, such as nickel, nickel-iron-chromium alloy, low-carbon alloy and the like, and has the size of 20cm in diameter and 60cm in height.

As shown in FIG. 2, the feed screen 21 is a circular feed screen, made of a stainless steel material 18cm in diameter with 100 mesh openings.

The combustion mechanism 3 comprises a circular nozzle 31 and a fuel gas source 32, the circular nozzle 31 is an annular disc, a plurality of nozzles are uniformly arranged on the annular disc, and the circular nozzle 31 is connected with the inner wall of the cylinder 1 and communicated with the fuel gas source 32 outside the cylinder 1.

As shown in FIG. 3, the annular disk has 6 segments of nozzles with a diameter of 18cm for providing a high temperature flame in the apparatus, and the annular nozzle 31 is placed about 40cm below the feed screen 21 and is inclined inward by 30 degrees.

The fuel gas source 32 uses the fuel gas butane.

The annular flame formed by the annular nozzle 31 forms a high temperature flame region, the temperature of which can reach over 800 ℃, and when the second black powder passes through the flame, the reaction can be rapidly carried out.

The ozone strong oxidation mechanism 4 comprises a ground pole annular steel pipe 41, a high-voltage pole annular steel pipe 42, an annular insulating part 43, an oxygen gas source 44 and an alternating current power supply, wherein the ground pole annular steel pipe 41 is positioned on the upper side of the high-voltage pole annular steel pipe 42 and communicated with the oxygen gas source 44, an enamel layer 411 is arranged on the outer wall of the ground pole annular steel pipe 41, the annular insulating part 43 is arranged on the lower side of the high-voltage pole annular steel pipe 42, the annular insulating part 43 is grounded, and the loading is used for forming an electric field between the ground pole annular steel pipe 41 and the high-voltage pole annular steel pipe 42 on the alternating current power supply.

The oxygen that lets in earth's pole annular steel pipe 41 produces ozone under the electric field effect, upwards urges the whereabouts powder of floating, keeps the powder to have certain dead time, and can provide strong oxidizing property environment, has both formed effectual carbon cladding, prevents again through the strong oxidation of ozone that cladding carbon from to the taking of NCM surface oxygen in the sintering process, has effectively inhibited the escape of lattice oxygen.

A K-type thermocouple 11 penetrates through one side of the barrel body 1, and the K-type thermocouple 11 is located above the annular nozzle 31.

The K-type thermocouple 11 is used for detecting the flame combustion temperature, and the K-type thermocouple 11 is arranged 10cm above the circular nozzle 31.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.