CN101271972B - Lithium ion battery sandwich electrode piece and method for producing the same - Google Patents

Abstract

A preparation method of a lithium-ion battery sandwich electrode sheet, comprising the following steps: (1) selecting a binder and a conductive agent, and uniformly dispersing them in an N-methylpyrrolidone solvent to prepare a binder-conductive agent mixture; (2) ) fully and evenly mixing the binder-conducting agent mixture with the lithium ion battery electrode material; (3) coating and drying the prepared slurry on a coating machine; (4) using a rolling machine to prepare the prepared slurry The electrode sheet is pressed until the porosity is between 25% and 40%; (5) recoating the binder-conductive agent mixture on the surface of the electrode sheet to obtain a new coating with a thickness between 2 microns and 5 microns; ( 6) Using a counter-roller to press the entire electrode sheet once. The pole piece manufactured by the method has the advantages of good mechanical performance, stable electrochemical cycle performance and the like. The invention also relates to using the method to manufacture positive and negative pole pieces of lithium ion batteries and lithium ion batteries manufactured by using such positive and negative pole pieces.

Description

Lithium-ion battery sandwich electrode sheet and preparation method thereof

technical field

The invention relates to a lithium-ion battery sandwich electrode sheet and a preparation method thereof, in particular to a lithium-ion battery sandwich electrode sheet prepared by a two-step coating method.

Background technique

Lithium-ion battery is a high-performance secondary battery. It has the advantages of high working voltage, high volume and weight energy density, long life, low self-discharge rate, no memory effect, and good for the environment. It is widely used in mobile communication equipment , notebook computers, digital cameras, digital video cameras, personal digital assistants, electric vehicles and other fields.

Then, as the public's awareness of environmental protection is further awakened, the development of power lithium-ion batteries for electric vehicles has gradually become the main direction of lithium-ion battery development. Different from ordinary lithium-ion batteries for communications, power lithium-ion batteries have requirements for the overall performance of the battery. Higher, especially for the specific energy of the battery, high-current discharge properties and battery life. Recently, the US Department of Energy proposed the standard for lithium-ion batteries for hybrid electric vehicles: under the condition of 70% depth of discharge The specific energy density is 207Wh/L, the pulse discharge power is 45kW, and the battery life exceeds 2000 times when the capacity retention rate is 70%. In order to approach and meet these requirements, on the one hand, battery researchers are required to focus on the research and development of high-capacity and long-life electrode materials with stable performance as soon as possible. However, according to the research results in recent years, finding new electrode materials that meet these requirements, In particular, the positive electrode material is not easy; on the other hand, from the perspective of battery technology, the battery process parameters are updated, and the existing electrode materials are used to make the performance of the battery meet the requirements of the power lithium-ion battery.

Contents of the invention

The object of the present invention is to make the sandwich electrode sheet of lithium ion battery and provide a kind of preparation method of the sandwich electrode sheet of lithium ion battery, the purpose of the present invention is achieved by following measures:

A preparation method of lithium ion battery sandwich electrode sheet, it comprises the following steps:

(1) Select polyvinylidene fluoride binder and acetylene black conductive agent, and its weight ratio is between 5:1 and 1:1, and uniformly disperse in N-methylpyrrolidone (NMP) solvent to prepare binder- conductive agent mixture;

(2) Mix the binder-conductive agent mixture with the lithium-ion battery electrode material for slurrying, and control the total weight ratio of the polyvinylidene fluoride binder and the acetylene black conductive agent in the electrode sheet between 2% and 8%. , fully mix the slurry evenly;

(3) Coating and drying the prepared slurry on a coating machine, and controlling the thickness of the electrode sheet between 40 microns and 120 microns;

(4) Use a rolling machine to compress the prepared electrode sheet to a porosity between 25% and 40%;

(5) Evenly disperse the polyvinylidene fluoride binder and the acetylene black conductive agent with a weight ratio of 5:1 to 1:1 in N-methylpyrrolidone to prepare another slurry, and the other slurry The material is re-coated on the surface of the electrode sheet, and the dry thickness of the new coating is between 2 microns and 5 microns;

(6) Using a counter-roller to press the entire electrode sheet once.

In the step (1), the polyvinylidene fluoride binder and the acetylene black conductive agent are selected, and their weight ratio is controlled at about 2:1.

The lithium-ion battery electrode material in the described step (2) comprises the lithium-ion battery active material selected from the following materials:

1) Li _x Ni _1-y M _y A _z O _2-z ;

2) Li _x Co _1-y M _y A _z O _2-z ;

3) Li _x Mn _1-y M _y A _z O _2-z ;

4) Li _x Fe _1-y M _y PO ₄ ;

5) Li _x Ni _a Co _b Mn _c O ₂ , a+b+c=1;

6) Natural graphite;

7) Artificial graphite;

Among them: 0.9≤x≤1.1, 0≤y≤0.2, 0≤z≤0.2, M is one or 2 selected from Mn, Co, Ni, Fe, Al, Cu, Cr, Mg, Ba or rare earth elements Elements, A is one selected from F, S, P, Cl.

The binder-conductive agent mixture in the step (2) is mixed with the lithium-ion battery electrode material and stirred at a high speed at a speed of 3000 to 4000 revolutions per minute, stirring for 10 minutes every time, stopping for 10 minutes in the middle, and the high-speed stirring takes a long time in 2 hours.

In the step (6), the electrode center layer is pressed by a counter-roller, so that the porosity of the electrode sheet is 25% to 40%.

The thickness of the new coating in the step (6) is about 3 microns, and the pressure of 3-5 atmospheric pressure is used to press the whole once.

In the step (6), use a counter-roller to press the electrode sheet with a pressure of 3 to 5 atmospheres.

Another object of the present invention is to provide a lithium-ion battery sandwich electrode sheet manufactured according to the above preparation method of a lithium-ion battery sandwich electrode sheet and a lithium-ion battery prepared using such a sandwich electrode sheet.

Compared with the prior art, the sandwich electrode sheet prepared according to the preparation method provided by the present invention has the following advantages:

(1) The specific capacity and specific energy of the electrode are high. The amount of binder and conductive agent used in this electrode material is less, the total amount of electrode material coating additives is no more than 3% (weight ratio), plus the amount of coating layer, additives only account for 5% of the total weight of electrode materials. % to 6%, which is much lower than the 10% to 15% of common electrode materials, and the reduction of inert substances is conducive to improving the specific capacity and specific energy of electrode materials.

(2) The mechanical properties of the electrode are good. This surface-coated sandwich electrode material is not prone to the phenomenon of falling off of the electrode active material (that is, "dropping"), and the electrode sheet has excellent toughness and good processability.

(3) Good stability. The surface coating layer can reduce the direct contact between the electrode active material and the main components of the electrolyte, thereby reducing the dissolution of the active material during the electrode cycle, which also reduces the dissolved Mn, Ni, Co, and Fe ions from passing through the battery separator to the negative electrode material The possibility of surface deposition, therefore, the lithium-ion battery prepared by this type of electrode has good cycle performance.

Description of drawings

The lithium-ion battery sandwich electrode sheet of the present invention and its preparation method will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Fig. 1 is a schematic cross-sectional structure diagram of a sandwich electrode sheet prepared by the two-step coating method of the present invention.

Fig. 2 is a graph of the cycle performance of a battery assembled with a sandwich electrode sheet prepared by the two-step coating method of the present invention and a common electrode sheet.

Detailed ways

The lithium-ion battery sandwich electrode sheet of the present invention and the preparation method thereof will be further described in conjunction with the examples below. The lithium-ion battery electrode material involved in the preparation method includes materials selected from the following materials 1) to 6):

1) Li _x Ni _1-y M _y A _z O _2-z ;

2) Li _x Co _1-y M _y A _z O _2-z ;

3) Li _x Mn _1-y M _y A _z O _2-z ;

4) Li _x Fe _1-y M _y PO ₄ ;

5) Li _x Ni _a Co _b Mn _c O ₂ , a+b+c=1;

6) Commonly used lithium-ion battery anode materials (natural graphite or artificial graphite);

Among them: 0.9≤x≤1.1, 0≤y≤0.2, 0≤z≤0.2, M is one or 2 selected from Mn, Co, Ni, Fe, Al, Cu, Cr, Mg, Ba or rare earth elements Elements, A is one selected from F, S, P, Cl.

Example 1

Taking LiNi _0.8 Co _0.15 Al _0.05 O ₂ as the research object, using optimized electrode additives (including vinylidene fluoride binder and acetylene black conductive agent) and two-step coating method, an electrode sheet with a service life of more than 2000 times was prepared (The capacity retention rate is more than 70%). This novel electrode sheet preparation method can be used in power lithium ion batteries. The specific preparation method of this sandwich electrode sheet comprises the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 10g of acetylene black conductive agent in 350g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: Take 120g of the binder-conductive agent mixture prepared in the first step, mix it with 200g LiNi _0.8 Co _0.15 Al _0.05 O ₂ to make slurry, stir at a high speed of 4000 rpm, and stir for 10 minutes every time, pause in the middle 10 minutes, the high-speed stirring time is not less than 2 hours, and the whole slurry is fully mixed and even.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the thickness of the dried electrode sheet between 40 μm and 120 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 30%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 3g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 2 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 2

Taking _LiCoO2 as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 12g of acetylene black conductive agent in 400g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: Take 120g of the binder-conductive agent mixture prepared in the first step, mix it with 200g LiCoO ₂ to make slurry, stir at a high speed of 4000 rpm, stir for 10 minutes every time, stop for 10 minutes in the middle, and stir at a high speed The time is not less than 2 hours, and the whole slurry is fully mixed evenly.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 40 μm and 100 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 35%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 4g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 2 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 3

Taking LiMn ₂ O ₄ as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 10g of acetylene black conductive agent in 370g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: take 150g of the binder-conductive agent mixture prepared in the first step, mix it with 200g LiMn ₂ O ₄ and make a slurry, stir at a high speed of 3000 revolutions per minute, stir every 10 minutes, and stop for 10 minutes in the middle, The high-speed stirring time is not less than 2 hours, and the whole slurry is fully mixed evenly.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 50 μm and 100 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 35%.

Step 5: Take 5g of selected polyvinylidene fluoride (PVDF) binder and 2.5g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare slurry, and re-coat on the surface of the electrode sheet Once, the dry thickness of the new coating is 2 μm to 5 μm.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 4

Taking _LiFePO4 as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 16g of acetylene black conductive agent in 350g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: Take 160g of the binder-conductive agent mixture prepared in the first step, mix it with 200g LiFePO ₄ to make slurry, stir at a high speed of 4000 rpm, stir for 10 minutes every time, stop for 10 minutes in the middle, and stir at a high speed The time is not less than 2 hours, and the whole slurry is fully mixed evenly.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 40 μm and 80 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 30%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 3g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 2 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 5

Taking LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 20g of acetylene black conductive agent in 300g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: get the binder-conducting agent mixture 160g that the first step makes, and 200gLiCo _1/3 Ni _1/3 Mn _1/3 O ₂ mixed pulping, with the rotating speed of 4000 revolutions per minute high-speed stirring, every Stir for 10 minutes, pause for 10 minutes in the middle, and stir at high speed for no less than 2 hours to fully mix the entire slurry.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 40 μm and 120 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 30%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 3g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 2 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 6

Taking mesophase carbon microspheres (MCMB) as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 10g of acetylene black conductive agent in 300g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: Take 100g of the binder-conductive agent mixture prepared in the first step, mix 50g of NMP and 200g of mesophase carbon microspheres to make slurry, and stir at a high speed of 4000 rpm, every stirring for 10 minutes, pause in the middle 10 minutes, the high-speed stirring time is not less than 2 hours, and the whole slurry is fully mixed and even.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 40 μm and 120 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 35%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 2g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 2 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

Example 7

Taking natural graphite beads (Natural Graphite Beads) as the research object, the specific preparation method of this sandwich electrode sheet includes the following steps:

The first step: uniformly disperse 20g of polyvinylidene fluoride (PVDF) binder and 8g of acetylene black conductive agent in 320g of N-methylpyrrolidone (NMP) solvent to prepare a binder-conductive agent mixture.

The second step: Take 100g of the binder-conductive agent mixture prepared in the first step, mix 80g of NMP and 200g of natural graphite microspheres to make slurry, stir at a high speed of 4000 revolutions per minute, stir for 10 minutes every time, and stop for 10 minutes in the middle. Minutes, the high-speed stirring time is not less than 2 hours, and the whole slurry is fully mixed evenly.

Step 3: Coating and drying the prepared slurry on a coating machine, and controlling the dry thickness of the electrode sheet between 40 μm and 120 μm.

Step 4: Use a rolling machine to press the prepared electrode sheet to a porosity of about 35%.

Step 5: Take another 5g of selected polyvinylidene fluoride (PVDF) binder and 3g of acetylene black conductive agent, evenly disperse in 100g of N-methylpyrrolidone (NMP) to prepare a slurry, and re-coat the surface of the electrode sheet once , The dry thickness of the new coating is 3 μ m ~ 5 μ m.

Step 6: Use a counter-rolling machine to re-press the entire electrode sheet once with a pressure of about 3 to 5 atmospheres.

The microstructure of the electrode sheet prepared by the above method is complex, please refer to FIG. 1 for the schematic cross-sectional structure of the electrode sheet. The electrode consists of four layers, from the surface to the inside are the surface coating layer 1, this layer is a composite of binder and conductive agent, the thickness is not more than 5μm, the second layer is the electrode material layer 2, this layer It is the central layer or the main layer of the electrode. Below the central layer is the surface coating 3 of the current collector (this layer does not exist when using a common current collector), and the bottom layer is an aluminum foil current collector 4.

Compared with ordinary electrodes, the advantages of this composite electrode sheet are as follows:

(1) The specific capacity and specific energy of the electrode are high. The amount of binder and conductive agent used in this electrode material is less, the total amount of electrode material coating additives is no more than 3% (weight ratio), plus the amount of coating layer, additives only account for 5% of the total weight of electrode materials. % to 6%, which is much lower than the 10% to 15% of common electrode materials, and the reduction of inert substances is conducive to improving the specific capacity and specific energy of electrode materials.

(2) The mechanical properties of the electrode are good. The surface-coated electrode material is not prone to shedding of the electrode active material (that is, material dropping phenomenon), and the electrode sheet has excellent toughness and good processability.

(3) Good stability. Since the surface coating layer of this electrode material can reduce the direct contact between the electrode active material and the main components of the electrolyte, thereby reducing the dissolution of the active material during the electrode cycle, which also reduces the dissolved Mn, Ni, and Co ions passing through the battery. The possibility of depositing the separator to the surface of the negative electrode material, because after a long cycle, the protective layer on the electrode surface can avoid the damage and structural collapse of the active material on the electrode surface close to the separator. From these aspects, this new type of lithium-ion battery sandwich The electrochemical cycle performance of the electrode sheet is particularly good.

The following description adopts the inventive method to manufacture the performance of the lithium-ion battery that pole piece produces

(1) Manufacture of positive electrode sheet

Using the slurry configured in Examples 1 to 5, the thickness of the aluminum foil current collector is 28 μm, the width is 320 mm, the thickness of the electrode center coating is about 70 μm, and the thickness of the surface coating is 3 μm. After drying the slurry coating in Example 1, it can be manufactured A positive electrode sheet with a density of 187g/m ² on one side was obtained. After pressing, the electrode sheet has excellent mechanical properties, is easy to be wound and processed, and the active material is not easy to fall off from the current collector, and there is no "dropping" phenomenon.

(2) Manufacture of negative electrode sheet

With the slurry configured in Examples 6 to 7, the thickness of the copper foil current collector is 18 μm, the width is 320 mm, the thickness of the electrode center coating is about 50 μm, and the thickness of the surface coating is 3 μm. After drying with the slurry coating in Example 6, The negative electrode sheet with a density of 112g/m ² on one side can be prepared. After pressing, the electrode sheet has excellent mechanical properties and is easy to be wound.

(3) Manufacture of button batteries

Using the above-mentioned positive electrode sheet and negative electrode sheet, Celgard 2400 diaphragm, 1mol/L LiPF ₆ /EC+DEC (weight ratio is 1: 1) electrolyte (containing 5% vinylidene carbonate (VC) additive), in Assemble the button battery in the glove box, and control the negative electrode sheet to have a surplus of 5% to 10% compared with the corresponding positive electrode material in both capacity and area. According to the common process of button battery manufacturing, after cutting, drying, assembling, liquid injection, sealing and pressing, the resulting battery is formed.

(4) Formation of battery

The formation system of the battery is: use a current density of 0.1mA/cm ² to charge and discharge at a constant current for 3 times, the charge cut-off voltage of Example 1 is 4.1V, and the discharge cut-off voltage is 3.0V. After the formation is completed, the battery is cycled Performance Testing.

The system of the battery cycle performance test in Example 1 is to first charge the battery at a constant current density of 2mA/cm ² to 4.1V, then charge the battery at a constant voltage of 4.1V to a current density of 0.1mA/cm ² , and then let it stand 10 minutes, and finally discharge to 3.0V with a current density of 2mA/cm ² , let it stand for 10 minutes, and cycle 2000 times with this system.

The test shows that the cycle performance comparison of the sandwich electrode sheet prepared by this two-step coating method and the battery assembled by the electrode sheet prepared by the traditional method is shown in Figure 2. After the deep charge and discharge cycle, the battery capacity drops by more than 30% (curve A); and the electrode sheet prepared by the method of the present invention, the battery capacity only drops by about 10% (curve B). , the electrochemical lifetime has been significantly improved.

It can be seen from the above results that the method of using the lithium-ion battery sandwich electrode sheet prepared by the present invention is a method for producing a composite long-life electrochemical electrode sheet. The life of the battery electrode sheet produced by this method is significantly improved and can meet the requirements of hybrid power Lifetime requirements of lithium-ion batteries for automobiles. Not only that, the pulse discharge performance, specific energy and specific capacity of the battery have also been improved to varying degrees. Therefore, this electrode sheet preparation method will be of great significance to the future development of lithium-ion batteries.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the claims of the present invention shall fall within the scope of the claims of the present invention.

Claims (8)

1. a preparation method of lithium ion battery sandwich electrode sheet, described electrode sheet comprises electrode central layer, it is characterized in that, described electrode sheet preparation process comprises the following steps: (1) Select polyvinylidene fluoride binder and acetylene black conductive agent, its weight ratio is between 5:1 to 1:1, and uniformly disperse in N-methylpyrrolidone solvent to prepare binder-conductive agent mixture; (2) The binder-conductive agent mixture is mixed with the lithium ion battery electrode material to make pulp, and the weight ratio of the polyvinylidene fluoride binder and the acetylene black conductive agent in the electrode sheet is controlled at 2% to 8% in this step. %, fully mix the slurry evenly; (3) Coating and drying the prepared slurry on a coating machine to obtain an electrode center layer, controlling the thickness of the electrode center layer to be 40 microns to 120 microns; (4) Using a rolling machine to compress the prepared electrode center layer to a porosity between 25% and 40%; (5) Select polyvinylidene fluoride binder and acetylene black conductive agent again, its weight ratio is between 5:1 to 1:1, uniformly disperse in N-methylpyrrolidone to prepare another slurry, the all Said another slurry is re-coated once on the surface of the electrode center layer, and the dry thickness of the new coating is between 2 microns and 5 microns; (6) Using a counter-rolling machine to re-press the sandwich electrode piece as a whole. 2. The preparation method of lithium ion battery sandwich electrode sheet as claimed in claim 1, is characterized in that: in step (1), polyvinylidene fluoride binder and acetylene black conductive agent are selected, and its weight ratio is 2:1. 3. The preparation method of lithium-ion battery sandwich electrode sheet as claimed in claim 1, is characterized in that: described lithium-ion battery electrode material comprises the material that is selected from following material 1) to 6) representation: 1) Li _x Ni _1-y M _y A _z O _2-z ; 2) Li _x Co _1-y M _y A _z O _2-z ; 3) Li _x Mn _1-y M _y A _z O _2-z ; 4) Li _x Fe _1-y M _y PO ₄ ; 5) Li _x Ni _a Co _b Mn _c O ₂ , a+b+c=1; 6) Natural graphite or artificial graphite; Among them: 0.9≤x≤1.1, 0≤y≤0.2, 0≤z≤0.2, M is one or 2 selected from Mn, Co, Ni, Fe, Al, Cu, Cr, Mg, Ba or rare earth elements Elements, A is one selected from F, S, P, Cl. 4. The preparation method of the lithium-ion battery sandwich electrode sheet as claimed in claim 1, characterized in that: use a counter-roller to press the electrode center layer, and control the porosity of the electrode center layer to 30%. 5 . The method for preparing a lithium-ion battery sandwich electrode sheet according to claim 1 , wherein the thickness of the new coating is 3 microns, and the whole is pressed once with a pressure of 3 to 5 atmospheres. 6. The preparation method of lithium ion battery sandwich electrode sheet as claimed in claim 1, is characterized in that: after described binder-conductive agent mixture mixes with lithium ion battery electrode material, with the rotating speed of 3000 to 4000 revolutions per minute high-speed Stir, every 10 minutes of stirring, stop for 10 minutes in the middle, and the high-speed stirring time is not less than 2 hours. 7. A lithium-ion battery sandwich electrode sheet manufactured according to the method of any one of claims 1 to 6. 8. A lithium ion battery with the lithium ion battery sandwich electrode sheet according to claim 7.