CN114772582A - Composite carbon material and application thereof in lithium ion battery - Google Patents

Abstract

The invention discloses a preparation method of a composite carbon material, which comprises the following steps: dispersing carbon nanotubes, a surfactant and glucose in deionized water, and carrying out hydrothermal reaction to obtain hydrothermal carbon; and drying and carbonizing the hydrothermal carbon, mixing the carbonized hydrothermal carbon with potassium hydroxide, performing an activation reaction, washing with water to be neutral, and drying to obtain the composite carbon material. The invention also discloses the composite carbon material prepared by the preparation method and application of the composite carbon material in a lithium ion battery. When the carbon composite material disclosed by the invention is applied to a lithium ion battery taking LiI as a positive electrode material, the LiI can be adsorbed, the shuttle effect of the LiI in the battery is inhibited, the self-discharge of the lithium ion battery is reduced, and the rate characteristic and the cycle stability of the battery are improved; and a plurality of carbon materials are selected for combination, so that the contact between electrode active materials is greatly increased, the conductivity is improved, and the rapid charge and discharge of the battery are facilitated. The material used in the invention is easy to obtain, the preparation method is simple, and the industrial production is convenient.

Description

A composite carbon material and its application in lithium ion batteries

technical field

The invention relates to the technical field of lithium ion batteries, in particular to a composite carbon material and its application in lithium ion batteries.

Background technique

Compared with other secondary batteries, lithium-ion batteries have successfully dominated the energy market due to their high energy density and good cycle stability. With the rapid development of the lithium-ion battery industry, the market has put forward more stringent requirements for the rapid charge-discharge performance and high and low temperature performance of lithium-ion batteries. The optimization of cathode materials in lithium-ion batteries is one of the important ways to improve the above performance. one. High-nickel ternary is the mainstream development trend of cathode materials for lithium-ion batteries at present, but the structural stability of high-nickel and the cost of rare metal cobalt restrict the further development of high-nickel ternary.

Lithium iodide, as one of the cathode materials of lithium-ion batteries, is abundant in stock, low in cost, and the charge-discharge mechanism of conversion reaction type has little effect under high-rate and high-low temperature charge-discharge. However, under the existing formulation system, lithium iodide as the positive electrode material of lithium ion battery has problems such as poor conductivity, easy deliquescence, and serious ion shuttle effect. Therefore, it is urgent to find a suitable formulation system.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is the problem of existing lithium ion batteries using lithium iodide as a positive electrode material, thereby providing a composite carbon material and its application in lithium ion batteries.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is as follows:

The invention provides a preparation method of composite carbon material, comprising the following steps:

S1: disperse carbon nanotubes, surfactant and glucose in deionized water, and then perform hydrothermal reaction to obtain hydrothermal carbon;

S2: the hydrothermal carbon is dried and then carbonized, and the carbonized hydrothermal carbon is mixed with potassium hydroxide and activated to obtain a crude composite carbon material;

S3: washing the crude composite carbon material with water to neutrality and drying to obtain the composite carbon material.

Further, the carbon nanotube has a diameter of 5-20 nm and a tube length of 5-15 μm;

The surfactant is sodium dodecylbenzenesulfonate (SDBS).

The mass ratio of the carbon nanotubes, surfactant and glucose is 5-12:1:800-1500.

In step S1, the hydrothermal reaction temperature is 160-200°C, and the reaction time is 7-12h;

In step S2, carbonization is carried out in an argon atmosphere at 600-900 °C for 1-3 hours;

The activation reaction is 800-1000℃ for 1-3h.

The present invention also provides a composite carbon material prepared by the above preparation method.

The present invention also provides a lithium ion battery positive electrode slurry, comprising the following raw materials in parts by mass:

Lithium iodide 80-90 copies;

Conductive carbon 6-10 copies;

Binder 4-10 copies;

The conductive carbon is a mixture of the above-mentioned composite carbon material and at least one of Ketjen black (KB), carbon black (Super-P), multi-walled carbon nanotubes (MWCNT) or graphene (RGO). The material accounts for 20wt.%-80wt.% of the conductive carbon;

The binder is at least one of polyvinyl butyral (PVB), polyvinylpyrrolidone (PVP), vinylpyrrolidone-vinyl acetate copolymer (PVP-VA) or polyethylene glycol (PEG2000) .

The preparation method of the above-mentioned lithium ion battery positive electrode slurry is as follows: fully dispersing lithium iodide in ethanol, and then mixing conductive carbon and a binder to obtain the lithium ion battery positive electrode slurry, and the water content in the ethanol is less than 200ppm .

The preparation method of the above-mentioned lithium ion battery positive pole piece is as follows: coating the above-mentioned lithium ion battery positive pole slurry on a current collector in an inert environment, and drying to obtain the lithium ion battery positive pole piece.

The present invention also provides a lithium ion battery, which uses the above-mentioned positive electrode piece of the lithium ion battery as the positive electrode piece.

The preparation method of the above-mentioned lithium ion battery is as follows: encapsulating the dry cell obtained by assembling the positive pole piece, the negative pole piece and the electrolyte solution, drying, liquid injection, standing, and chemical formation to obtain the lithium ion battery.

The negative pole piece can choose graphite negative electrode, silicon carbon negative electrode or lithium metal as negative electrode, and the electrolyte is DOL/DME (1:1 vol.%) of 1M LiTFSI.

The scheme provided by the present invention has the following advantages:

1. In the carbon composite material provided by the present invention, in the preparation process, the hydrothermal carbon obtained by the hydrothermal reaction of glucose is further carbonized to obtain carbon-coated carbon nanotubes, and then potassium hydroxide is used to carry out the carbon-coated carbon nanotubes. After activation treatment, a carbon composite material with a specific surface area of 2500-4000 m ² /g is obtained.

2. When the carbon composite material provided by the present invention is applied to a lithium ion battery in which LiI is used as a positive electrode material, its ultra-high specific surface area can adsorb LiI in the electrode material, inhibit the shuttle effect of LiI in the battery, and reduce the self-discharge of the lithium ion battery. ; The carbon nanotubes in the composite material can improve the electrical conductivity and mechanical stability of the material while improving the rate characteristics and cycle stability of lithium-ion batteries.

3. The present invention selects a variety of carbon materials to combine, and the carbon materials with different properties are compounded multiple times, which will greatly increase the contact between the electrode active materials, improve the conductivity, and facilitate the rapid charge and discharge of the lithium ion battery.

4. The materials used in the present invention are easy to obtain, the preparation method is simple, and the industrial production is convenient.

Detailed ways

The following examples are provided for a better understanding of the present invention, and are not limited to the best embodiments, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by combining with the features of other prior art shall fall within the protection scope of the present invention.

If the specific experimental steps or conditions are not indicated in the examples, it can be carried out according to the operations or conditions of the conventional experimental steps described in the literature in this field. The reagents or instruments used without the manufacturer's indication are all conventional reagent products that can be obtained from the market.

Example 1

The present embodiment provides a composite carbon material, and its preparation method is as follows:

(1) Weigh 0.1g of carbon nanotubes, 10mg of sodium dodecylbenzenesulfonate, and 10g of glucose, add them to 100ml of deionized water, and ultrasonically disperse them uniformly;

(2) Pour the above-mentioned uniformly dispersed carbon nanotube aqueous solution into a hydrothermal reaction kettle, and hydrothermally react at 190 °C for 10 h to obtain hydrothermal carbon;

(3) The hydrothermal carbon after the reaction in the hydrothermal kettle is dried and then transferred to a tube furnace, protected by argon gas, and carbonized at 800 °C for 2 h to obtain carbon-coated carbon nanotubes; The tube and potassium hydroxide are evenly mixed at a mass ratio of 1:5 and then transferred to a tube furnace, and activated at 800 °C for 1 h to obtain a crude composite carbon material;

(4) Washing the crude composite carbon material to neutrality and drying to obtain the composite carbon material.

This embodiment also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 80g of lithium iodide in a ball mill, add ethanol, ball mill for 20min, then add 6g Ketjen black, 2g multi-wall carbon nanotubes, 2g composite carbon material, 10g polyvinylpyrrolidone powder, and continue ball milling for 4h to obtain a uniformly dispersed positive electrode Slurry with a solids content of 38 wt.%.

This embodiment also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

The present embodiment also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Example 2

The present embodiment provides a composite carbon material, and its preparation method is as follows:

(1) Weigh 0.1g of carbon nanotubes, 10mg of sodium dodecylbenzenesulfonate, and 10g of glucose, add them to 100ml of deionized water, and ultrasonically disperse them uniformly;

(2) Pour the above-mentioned uniformly dispersed carbon nanotube aqueous solution into a hydrothermal reaction kettle, and hydrothermally react at 190 °C for 10 h to obtain hydrothermal carbon;

(3) The hydrothermal carbon after the reaction in the hydrothermal kettle is dried and then transferred to a tube furnace, protected by argon gas, and carbonized at 800 °C for 2 h to obtain carbon-coated carbon nanotubes; The tube and potassium hydroxide are evenly mixed at a mass ratio of 1:5 and then transferred to a tube furnace, and activated at 800 °C for 1 h to obtain a crude composite carbon material;

(4) Washing the crude composite carbon material to neutrality and drying to obtain the composite carbon material.

This embodiment also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 80g of lithium iodide in a ball milling jar, add ethanol, ball mill for 20min, then add 4g Ketjen black, 2g multi-wall carbon nanotubes, 4g composite carbon material, 10g polyvinylpyrrolidone powder, continue ball milling for 4h to obtain a uniformly dispersed positive electrode Slurry with a solids content of 38 wt.%.

This embodiment also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

The present embodiment also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Example 3

The present embodiment provides a composite carbon material, and its preparation method is as follows:

(1) Weigh 0.1g of carbon nanotubes, 10mg of sodium dodecylbenzenesulfonate, and 10g of glucose, add them to 100ml of deionized water, and ultrasonically disperse them uniformly;

(2) Pour the above-mentioned uniformly dispersed carbon nanotube aqueous solution into a hydrothermal reaction kettle, and hydrothermally react at 190 °C for 10 h to obtain hydrothermal carbon;

(3) The hydrothermal carbon after the reaction in the hydrothermal kettle is dried and then transferred to a tube furnace, protected by argon gas, and carbonized at 800 °C for 2 h to obtain carbon-coated carbon nanotubes; The tube and potassium hydroxide are evenly mixed at a mass ratio of 1:5 and then transferred to a tube furnace, and activated at 800 °C for 1 h to obtain a crude composite carbon material;

(4) Washing the crude composite carbon material to neutrality and drying to obtain the composite carbon material.

This embodiment also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 90 g of lithium iodide in a ball milling jar, add ethanol, ball mill for 20 min, then add 2 g of Ketjen black, 2 g of multi-walled carbon nanotubes, 2 g of composite carbon material, 3 g of vinylpyrrolidone-vinyl acetate copolymer powder and 1 g of polyethylene. The ethylene glycol powder was continuously ball-milled for 4 hours to obtain a uniformly dispersed positive electrode slurry with a solid content of 33 wt.%.

This embodiment also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

The present embodiment also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Example 4

The present embodiment provides a composite carbon material, and its preparation method is as follows:

(1) Weigh 0.1g of carbon nanotubes, 10mg of sodium dodecylbenzenesulfonate, and 10g of glucose, add them to 100ml of deionized water, and ultrasonically disperse them uniformly;

(2) Pour the above-mentioned uniformly dispersed carbon nanotube aqueous solution into a hydrothermal reaction kettle, and hydrothermally react at 190 °C for 10 h to obtain hydrothermal carbon;

(3) The hydrothermal carbon after the reaction in the hydrothermal kettle is dried and then transferred to a tube furnace, protected by argon gas, and carbonized at 800 °C for 2 h to obtain carbon-coated carbon nanotubes; The tube and potassium hydroxide are evenly mixed at a mass ratio of 1:5 and then transferred to a tube furnace, and activated at 800 °C for 1 h to obtain a crude composite carbon material;

(4) Washing the crude composite carbon material to neutrality and drying to obtain the composite carbon material.

This embodiment also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 90g of lithium iodide in a ball mill, add ethanol, ball mill for 20min, then add 2g Ketjen black, 1g multi-wall carbon nanotube, 1g graphene, 2g composite carbon material, 3g polyvinyl butyral powder and 1g The vinylpyrrolidone-vinyl acetate copolymer powder was continuously ball-milled for 4 hours to obtain a uniformly dispersed positive electrode slurry with a solid content of 32 wt.%.

This embodiment also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

The present embodiment also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Example 5

The present embodiment provides a composite carbon material, and its preparation method is as follows:

(1) Weigh 0.1g of carbon nanotubes, 10mg of sodium dodecylbenzenesulfonate, and 10g of glucose, add them to 100ml of deionized water, and ultrasonically disperse them uniformly;

(2) Pour the above-mentioned uniformly dispersed carbon nanotube aqueous solution into a hydrothermal reaction kettle, and hydrothermally react at 190 °C for 10 h to obtain hydrothermal carbon;

(3) The hydrothermal carbon after the reaction in the hydrothermal kettle is dried and then transferred to a tube furnace, protected by argon gas, and carbonized at 800 °C for 2 h to obtain carbon-coated carbon nanotubes; The tube and potassium hydroxide are evenly mixed at a mass ratio of 1:5 and then transferred to a tube furnace, and activated at 800 °C for 1 h to obtain a crude composite carbon material;

(4) Washing the crude composite carbon material to neutrality and drying to obtain the composite carbon material.

This embodiment also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 90 g of lithium iodide in a ball milling jar, add ethanol, ball mill for 20 min, then add 1 g of multi-walled carbon nanotubes, 1 g of graphene, 4 g of activated carbon-coated carbon nanotube material, 3 g of polyvinyl butyral powder and 1 g of polyvinyl butyral powder. The vinylpyrrolidone powder was continuously ball-milled for 4 hours to obtain a uniformly dispersed positive electrode slurry with a solid content of 30 wt.%.

This embodiment also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

This embodiment also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well. Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive electrode, separator, and negative electrode in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Comparative Example 1

This comparative example also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 80g of lithium iodide in a ball milling jar, add ethanol, ball mill for 20min, then add 10g multi-wall carbon nanotubes, 10g polyvinylpyrrolidone powder, and continue ball milling for 4h to obtain a uniformly dispersed positive electrode slurry with a solid content of 38wt.%.

This comparative example also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

This comparative example also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Comparative Example 2

This comparative example also provides a lithium-ion battery cathode slurry, and the preparation method is as follows:

Take 90g of lithium iodide in a ball milling jar, add ethanol, ball mill for 20min, then add 6g multi-wall carbon nanotubes, 4g polyvinylpyrrolidone powder, and continue ball milling for 4h to obtain a uniformly dispersed positive electrode slurry with a solid content of 38wt.%.

This comparative example also provides a lithium-ion battery positive pole piece, and the preparation method is as follows:

The slurry was transferred to an inert environment glove box, coated on a stainless steel current collector in an inert environment, and dried to obtain the lithium ion battery positive electrode sheet.

This comparative example also provides a lithium-ion battery, and the preparation method is as follows:

Mix the negative electrode active material graphite, conductive carbon black, binder SBR, thickener CMC, and cyclic ester ethylene carbonate in a mass ratio of 93.5:2:3:0.5:1, add deionized water solvent, and stir well Then, the negative electrode slurry is obtained, which is coated on the stainless steel current collector, and dried to obtain the negative electrode pole piece of the lithium ion battery. Stack the positive pole piece, separator film, and negative pole piece in order, wrap the cell with aluminum plastic film, inject DOL/DME (1:1 vol.%) electrolyte containing 1M LiTFSI, and then package to obtain the finished lithium ion Battery.

Test example

The performance tests were performed on the lithium ion batteries obtained in the various examples and comparative examples.

The test items include 0.3C, 1C, 5C, and 10C charge-discharge tests at room temperature of 25°C and 1C tests at 0°C, -10°C, -20°C, and -30°C. The test results are shown in Table 1 and Table 2.

Table 1 Volume retention rate experiment of each embodiment and comparative example at different temperatures

Table 2 Volume retention rate experiments of different laps of each embodiment and comparative example

It can be seen from the above two tables that the low-temperature performance and long-cycle performance of the lithium-ion battery in the comparative example without the composite carbon material provided by the present application are far inferior to those of the embodiments of the present application, indicating that the composite carbon material provided by the present application can Improve the capacity retention of lithium-ion batteries at low temperatures and in long cycle life tests.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. A preparation method of a composite carbon material is characterized by comprising the following steps:

s1: dispersing carbon nano tubes, a surfactant and glucose in deionized water, and then carrying out hydrothermal reaction to obtain hydrothermal carbon;

s2: drying and carbonizing the hydrothermal carbon, mixing the carbonized hydrothermal carbon with potassium hydroxide, and performing an activation reaction to obtain a crude composite carbon material;

s3: and washing the crude composite carbon material with water to be neutral, and drying to obtain the composite carbon material.

2. The method according to claim 1, wherein the carbon nanotube has a tube diameter of 5 to 20nm and a tube length of 5 to 15 μm;

the surfactant is sodium dodecyl benzene sulfonate.

3. The method according to claim 1 or 2, wherein the mass ratio of the carbon nanotubes, the surfactant and the glucose is 5-12:1: 800-1500.

4. The method according to any one of claims 1 to 3, wherein in step S1, the hydrothermal reaction temperature is 160-200 ℃, and the reaction time is 7-12 h;

in step S2, carbonization is carried out at 900 ℃ for 1-3h under the argon environment;

the activation reaction is 800-1000 ℃ for 1-3 h.

5. A composite carbon material produced by the production method according to any one of claims 1 to 4.

6. The lithium ion battery anode slurry is characterized by comprising the following raw materials in parts by mass:

80-90 parts of lithium iodide;

6-10 parts of conductive carbon;

4-10 parts of a binder;

the conductive carbon is the composite carbon material of claim 5 mixed with at least one of ketjen black, carbon black, multi-walled carbon nanotubes, or graphene, the composite carbon material comprising 20-80 wt.% of the conductive carbon;

the binder is at least one of polyvinyl butyral, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer and polyethylene glycol.

7. The method for preparing a positive electrode slurry for a lithium ion battery as defined in claim 6, wherein lithium iodide is dispersed in ethanol sufficiently, and then conductive carbon and a binder are mixed to obtain the positive electrode slurry for a lithium ion battery.

8. A preparation method of a lithium ion battery positive pole piece is characterized in that the lithium ion battery positive pole slurry of claim 6 or the lithium ion battery positive pole slurry prepared by the preparation method of claim 7 is coated on a current collector in an inert environment and dried to obtain the lithium ion battery positive pole piece.

9. A lithium ion battery is characterized in that the lithium ion battery positive pole piece prepared by the preparation method of claim 8 is used as a positive pole piece.

10. The method for preparing the lithium ion battery of claim 9, wherein the lithium ion battery is obtained by packaging a dry electric core obtained by assembling the positive electrode plate, the negative electrode plate and the electrolyte, drying, injecting liquid, standing and forming.