CN113517423A - Positive electrode material, preparation method thereof, pole piece and preparation method thereof - Google Patents
Positive electrode material, preparation method thereof, pole piece and preparation method thereof Download PDFInfo
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- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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Abstract
The invention provides a positive electrode material, a preparation method thereof, a pole piece and a preparation method thereof. The cathode material comprises a low-cobalt active material and lithium iron phosphate, and the mass ratio of the low-cobalt active material to the lithium iron phosphate is 90:10-99: 1. The pole piece comprises the positive pole material. The preparation method of the pole piece comprises the following steps: and mixing the conductive slurry with the positive electrode material to obtain positive electrode slurry, coating the positive electrode slurry on a current collector, drying and rolling to obtain the pole piece. The cathode material provided by the invention can effectively solve the problem of rapid voltage drop of the low-cobalt active material at the final stage of discharge, and the reaction potential of the electrode at the low potential is improved by blending lithium iron phosphate with lower reaction potential and cooperating with lithium ion diffusion of the low-cobalt active material at the low potential, so that the energy density of the battery is improved.
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to a positive electrode material, a preparation method thereof, a pole piece and a preparation method thereof.
Background
Ternary layered material LiNixCoyMn1-x-yO2The high-capacity high-voltage power battery has high theoretical specific capacity of 274mAh/g, high reaction platform voltage of 3.0-4.3V and excellent reaction kinetics, so that the high-capacity high-voltage power battery is widely applied to a high-energy-density power battery system. However, the ternary material widely used at present has a high Co content (y is more than 0.1), and Co ore is increasingly in short supply as a rare mineral resource. The prior art solves the problems of material cost and limited cobalt ore resources by reducing the content of ternary Co, and develops a low-cobalt active material LiNixCoyMn1-x-yO2(y is less than 0.05).
Low cobalt active material LiNixCoyMn1-x-yO2The decrease of the Co content in (y is less than 0.05) can reduce the overall conductivity of the material and improve the diffusion barrier of lithium ions in crystal lattices, thereby bringing about a serious reaction kinetics retardation problem and influencing the capacity exertion of the battery. There is a significant voltage drop especially at the end of discharge, which results in a low cobalt active material, LiNixCoyMn1-x-yO2(y is less than 0.05) energy density is reduced, and development and application of the material are influenced.
CN110931738A discloses a complex phase high voltage anode material which is composed of LiNi with hexagonal layered structurex-aCoy-aMnz- aMbO2Rock salt phase (Li + N) O and coating agent AThe chemical formula is LiNix-aCoy-aMnz-aMbO2A (Li + N) O.cA; wherein a is more than 0 and less than 0.01, x is more than or equal to 0.33 and less than 1.0, y is more than or equal to 0 and less than or equal to 0.33, z is more than 0.01 and less than 0.5, b is more than 0 and less than 0.02, c is more than 0.001 and less than 0.01, and x + y + z is 1; m is one or more of Mg, Al, Ti, Zr, Sr, Y, Ce, B, W, La, Sn, Zn and Mo; n is one or more of Ni, Co and Mn; the coating agent A is TiO2、ZrO2、Al2O3、SnO2、Li3PO4、Li2B4O7、Li4TiO4And Li2SiO3One kind of (1). However, the method exists in the LiNi which is a low-cobalt active materialxCoyMn1-x-yO2The energy density is to be improved due to the rapid voltage drop at the end of discharge.
CN111900380A discloses a method for preparing nickel cobalt lithium manganate single crystal ternary material. The method comprises the following steps: (1) lithium carbonate and precursor (Ni)0.55Co0.15Mn0.3)(OH)2Uniformly mixing with a zirconium compound to obtain a mixture; (2) placing the mixture in a sagger, scribing, cutting into pieces, and calcining to obtain single crystal Li (Ni)0.55Co0.15Mn0.3)O2A material block; (3) the material blocks are subjected to coarse crushing, airflow crushing and sieving in sequence to obtain black powder; (4) and (3) mixing the black powder and the additive by a high-speed dry method, and sintering to obtain the additive-coated black powder material. But the ternary material of the method has higher Co content, thereby improving the production cost.
CN111384392A discloses a high-nickel low-cobalt high-voltage-resistant ternary cathode material and a preparation method thereof. The piezoelectric ternary cathode material comprises a coating layer and LiNi doped with a metal element M0.65Co0.07Mn0.28O2A matrix, wherein the metal element M is at least two selected from Nb, Mg, Y, Ti, W, Al and Zr; the coating layer contains metal elements M' selected from at least two of Mg, Y, Ti, W, Al and Zr. But the ternary material of the method has higher Co content, thereby improving the production cost.
Disclosure of Invention
In view of the above-mentioned disadvantages in the prior art, the present invention aims to provide a positive electrode material, a preparation method thereof, a pole piece and a preparation method thereof. The positive electrode material provided by the invention solves the problem of low energy density in the low-cobalt active material.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a cathode material, which comprises a low-cobalt active material and lithium iron phosphate, wherein the mass ratio of the low-cobalt active material to the lithium iron phosphate is 90:10-99: 1.
The low-cobalt active material is characterized in that the percentage of cobalt in other metal elements except lithium in the low-cobalt active material is less than 5%.
In the anode material provided by the invention, the lithium iron phosphate is matched with the low-cobalt active material, the electrochemical reaction potential of the lithium iron phosphate is 3.0-3.4V, and the theoretical specific capacity is 170 mAh/g. The lithium iron phosphate is mixed with a low-cobalt active material, and lithium ion migration of the lithium iron phosphate at a reaction potential can generate a synergistic effect on lithium ion diffusion of the low-cobalt active material at a low potential (3.0-3.4V), so that the reaction potential of an electrode at the low potential is improved, and the overall energy density of the battery is improved.
In the invention, the mass ratio of the low-cobalt active material to the lithium iron phosphate is 90:10-99:1, such as 90:10, 92:8, 94:6, 96:4, 98:2 or 99: 1. In the invention, too much lithium iron phosphate can cause the whole voltage of the battery to be too low, thereby reducing the energy density; if the amount of lithium iron phosphate is too small, the function of lifting the low-potential voltage platform cannot be fully exerted.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
As a preferable technical scheme of the invention, the chemical formula of the low-cobalt active material is LiNixCoyM1-x-yO2Wherein 0.5. ltoreq. x.ltoreq.0.9, for example x is 0.5, 0.6, 0.7, 0.8 or 09, etc., 0. ltoreq. y.ltoreq.0.05, for example y is 0, 0.01, 0.02, 0.03, 0.04 or.0.05, etc., M is Mn and/or Al.
Preferably, M is Mn.
Preferably, the low cobalt active material is spherical secondary particles or a single crystal.
Preferably, the spherical secondary particles have a D50 particle size of 8-18 μm, such as 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, or 18 μm, and the like. The purpose of using this D50 range is to increase the bulk density of the material without reducing the reaction kinetics of the active species.
Preferably, the single crystal has a D50 particle size of 2-7 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, or the like. The D50 range is adopted to ensure the reaction kinetics of the material, reduce the side reaction with the electrolyte and ensure the long-term performance.
As a preferable technical scheme of the invention, the lithium iron phosphate is spherical micron lithium iron phosphate or nano lithium iron phosphate.
Preferably, the spherical micro-scale lithium iron phosphate has a D50 particle size of 5-15 μm, such as 5 μm, 10 μm, or 15 μm. The D50 range is adopted to improve the whole compaction density of the material and ensure the reaction dynamic performance of the material.
Preferably, the D50 particle size of the nano lithium iron phosphate is 0.5-2 μm, such as 0.5 μm, 1 μm, 1.5 μm or 2 μm. The purpose of this D50 range is to ensure the electrochemical reaction kinetics of the material itself and to reduce side reactions with the electrolyte.
In a second aspect, the present invention provides a method for producing the positive electrode material according to the first aspect, the method comprising the steps of:
and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio to obtain the cathode material.
As the preferable technical scheme of the invention, the mixing is stirring mixing;
preferably, the stirring and mixing is high-speed stirring and mixing.
In the present invention, the stirring rate of the high-speed stirring and mixing is 30 revolutions per minute by rotation and 2000 revolutions per minute or more, the same applies below.
In a third aspect, the present invention provides a pole piece comprising the positive electrode material according to the first aspect.
The pole piece provided by the invention uses the positive electrode material provided by the first aspect, so that the energy density of the battery can be improved.
As a preferred technical solution of the present invention, the electrode sheet includes a current collector and a coating layer coated on the current collector, and the coating layer includes the positive electrode material according to the first aspect.
Preferably, the coating further comprises a conductive agent and a binder.
Preferably, the conductive agent comprises conductive carbon black and/or conductive carbon nanotubes.
Preferably, the binder comprises any one of polyvinylidene fluoride, polytetrafluoroethylene or styrene butadiene rubber or a combination of at least two of them.
Preferably, in the coating, the mass ratio of the positive electrode material, the conductive agent and the binder is 100 (1-2) to (0.5-1.5), such as 100:1:0.5, 100:1.5:1, 100:2:0.5 or 100:1: 1.5.
Preferably, the current collector is an aluminum foil.
In a fourth aspect, the present invention provides a method for preparing a pole piece according to the third aspect, the method includes the following steps:
mixing the conductive slurry with the positive electrode material to obtain positive electrode slurry, coating the positive electrode slurry on a current collector, drying and rolling to obtain the pole piece.
In a preferred embodiment of the present invention, the mixing is stirring.
Preferably, the stirring and mixing is high-speed stirring and mixing.
Preferably, the coating is coating with a doctor blade.
Preferably, the drying temperature is 100-.
Preferably, the drying time is 15-25min, such as 15min, 17min, 20min, 23min or 25min, etc.
Preferably, after said rolling, the rolled product is cut.
Preferably, the conductive paste includes formulated amounts of a conductive agent, a binder, and a solvent.
Preferably, the solvent comprises water or a nitrogen methyl pyrrolidone solution.
Preferably, the mass ratio of the solvent to the binder is (35-45):1, such as 35:1, 40:1 or 45:1, etc.
As a further preferable technical scheme of the preparation method of the pole piece, the method comprises the following steps:
(1) stirring and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio at a high speed to obtain a positive electrode material; dispersing and stirring the conductive agent, the binder and the solvent according to the formula ratio to obtain conductive slurry;
(2) and (2) stirring and mixing the positive electrode material and the conductive slurry obtained in the step (1) at a high speed to obtain positive electrode slurry, coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying box, drying at 140 ℃ for 15-25min, and then rolling and cutting to obtain the pole piece.
Compared with the prior art, the invention has the following beneficial effects:
the cathode material provided by the invention can effectively solve the problem of rapid voltage drop of the low-cobalt active material at the final stage of discharge, and the reaction potential of the electrode at the low potential is improved by blending lithium iron phosphate with lower reaction potential and cooperating with lithium ion diffusion of the low-cobalt active material at the low potential, so that the energy density of the battery is improved.
Drawings
Fig. 1 is a discharge curve at 2C discharge rate after the electrode sheets provided in example 1 and comparative example 1 were prepared into batteries.
Fig. 2 is a discharge curve at 3C discharge rate after the electrode sheets provided in example 1 and comparative example 1 were prepared into batteries.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The following are typical but non-limiting examples of the invention:
example 1
The cathode material provided by this embodiment is composed of a low-cobalt active material and lithium iron phosphate, and the mass ratio of the low-cobalt active material to the lithium iron phosphate is 97: 3. The low-cobalt active material is a single crystal ternary material LiNi0.75Mn0.25O2(D50 is 5 μm), and the lithium iron phosphate is spherical micron lithium iron phosphate (D50 is 10 μm).
The pole piece provided by the embodiment comprises a current collector and a coating layer coated on the current collector, wherein the current collector is an aluminum foil, and the coating layer comprises the positive electrode material, conductive carbon black, conductive carbon nanotube and polyvinylidene fluoride binder provided by the embodiment with the mass ratio of 100:1:0.5: 1. The pole piece is coated on two sides, and the thickness of the coating on each side is 2 micrometers.
In this embodiment, the positive electrode material and the electrode sheet are prepared according to the following methods:
(1) stirring and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio at a high speed to obtain a positive electrode material; dispersing and stirring the conductive agent (conductive carbon black and conductive carbon nano tube), the binder (PVDF) and the solvent (N-methyl pyrrolidone NMP) for 2h at a high speed according to the formula ratio to obtain conductive slurry; the mass ratio of the solvent to the binder is 40: 1.
(2) And (2) stirring and mixing the positive electrode material and the conductive slurry in the formula amount in the step (1) at a high speed to obtain positive electrode slurry, coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a forced air drying oven, drying for 20min at 120 ℃, and then rolling and cutting to obtain the pole piece.
Example 2
The cathode material provided by this embodiment is composed of a low-cobalt active material and lithium iron phosphate, and the mass ratio of the low-cobalt active material to the lithium iron phosphate is 90: 10. The low-cobalt active material is a single crystal ternary material LiNi0.75Mn0.25O2(D50 is 7 μm), phosphoric acidThe lithium iron is spherical micron lithium iron phosphate (D50 is 5 μm).
The pole piece provided by the embodiment comprises a current collector and a coating layer coated on the current collector, wherein the current collector is an aluminum foil, and the coating layer comprises the positive electrode material, conductive carbon black, conductive carbon nanotube and polyvinylidene fluoride binder provided by the embodiment with the mass ratio of 100:1:1: 0.5. The pole piece is coated on two sides, and the thickness of the coating on each side is 2 micrometers.
In this embodiment, the positive electrode material and the electrode sheet are prepared according to the following methods:
(1) stirring and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio at a high speed to obtain a positive electrode material; dispersing and stirring the conductive agent (conductive carbon black and conductive carbon nano tube), the binder (PVDF) and the solvent (N-methyl pyrrolidone NMP) for 2h at a high speed according to the formula ratio to obtain conductive slurry; the mass ratio of the solvent to the binder is 35: 1.
(2) And (2) stirring and mixing the positive electrode material and the conductive slurry in the formula amount in the step (1) at a high speed to obtain positive electrode slurry, coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a forced air drying oven, drying for 25min at 100 ℃, and then rolling and cutting to obtain the pole piece.
Example 3
The cathode material provided by this embodiment is composed of a low-cobalt active material and lithium iron phosphate, and the mass ratio of the low-cobalt active material to the lithium iron phosphate is 99: 1. The low-cobalt active material is spherical secondary particle LiNi0.5Co0.05Mn0.45O2(D50 is 10 μm), and the lithium iron phosphate is nano lithium iron phosphate (D50 is 0.5 μm).
The pole piece provided by the embodiment comprises a current collector and a coating layer coated on the current collector, wherein the current collector is an aluminum foil, and the coating layer comprises the positive electrode material, conductive carbon black, conductive carbon nano tubes and a binder polyvinylidene fluoride provided by the embodiment with the mass ratio of 100:0.5:0.5: 1.5. The pole piece is coated on two sides, and the thickness of the coating on each side is 2 micrometers.
In this embodiment, the positive electrode material and the electrode sheet are prepared according to the following methods:
(1) stirring and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio at a high speed to obtain a positive electrode material; dispersing and stirring the conductive agent (conductive carbon black and conductive carbon nano tube), the binder (PVDF) and the solvent (N-methyl pyrrolidone NMP) for 2h at a high speed according to the formula ratio to obtain conductive slurry; the mass ratio of the solvent to the binder is 45: 1.
(2) And (2) stirring and mixing the positive electrode material and the conductive slurry in the formula amount in the step (1) at a high speed to obtain positive electrode slurry, coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a forced air drying oven, drying for 15min at 140 ℃, and then rolling and cutting to obtain the pole piece.
Example 4
The cathode material provided by this embodiment is composed of a low-cobalt active material and lithium iron phosphate, and the mass ratio of the low-cobalt active material to the lithium iron phosphate is 95: 5. The low-cobalt active material is spherical secondary particle LiNi0.5Co0.05Mn0.45O2(D50 is 18 μm), and the lithium iron phosphate is nano lithium iron phosphate (D50 is 0.5 μm).
The pole piece provided by the embodiment comprises a current collector and a coating layer coated on the current collector, wherein the current collector is an aluminum foil, and the coating layer comprises the positive electrode material, conductive carbon black, conductive carbon nano tubes and a binder polyvinylidene fluoride provided by the embodiment with the mass ratio of 100:0.5:0.5: 1.5. The pole piece is coated on two sides, and the thickness of the coating on each side is 2 micrometers.
Comparative example 1
The present comparative example is different from example 1 in that the positive electrode material is entirely composed of the same low cobalt active material as example 1, and does not contain any lithium iron phosphate. The electrode sheet provided by the present comparative example was the same as example 1 except that the positive electrode material of the present comparative example was used.
Comparative example 2
The comparative example is different from example 1 in that the mass ratio of the low cobalt active material to the lithium iron phosphate was 85: 15. The electrode sheet provided by the present comparative example was the same as example 1 except that the positive electrode material of the present comparative example was used.
Comparative example 3
The present comparative example is different from example 1 in that the mass ratio of the low cobalt active material to the lithium iron phosphate is 99.5: 0.5. The electrode sheet provided by the present comparative example was the same as example 1 except that the positive electrode material of the present comparative example was used.
Test method
The electrode sheets obtained in each example and comparative example were used as a positive electrode, a lithium sheet was used as a negative electrode, and an electrolyte was 1M LiPF6(the solvent is a mixed solution of Ethylene Carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 1: 1), assembling the button cell, and carrying out an electrochemical test.
Charging to 4.35V voltage at 0.33C rate at room temperature, and then discharging the battery to 3V voltage at 2C rate to obtain a discharge curve as shown in FIG. 1; then, the battery was charged to a voltage of 4.35V at a rate of 0.33C, and then the battery was discharged to a voltage of 3V at a rate of 3C, resulting in a discharge curve as shown in fig. 2.
As can be seen from FIGS. 1 and 2, under the 2C rate discharge condition, the discharge voltage plateau of example 1 between 3.3V and 3.5V is significantly improved compared with that of comparative example 1; under the condition of 3C rate discharge, the discharge voltage plateau of the example 1 between 3.2 and 3.4V is obviously improved compared with that of the comparative example 1.
Under the test conditions of 0.33C rate charging and 0.33C rate discharging, the energy density of the button cell is tested, and the test results are shown in the following table:
TABLE 1
| Test sample | Energy Density (Wh/kg) |
| Example 1 | 223 |
| Example 2 | 213 |
| Example 3 | 208 |
| Example 4 | 205 |
| Comparative example 1 | 207 |
| Comparative example 2 | 195 |
| Comparative example 3 | 210 |
It can be known from the above embodiments and comparative examples that the positive electrode material provided by the embodiments can effectively overcome the problem of rapid voltage drop of the low-cobalt active material at the end of discharge, and the reaction potential of the electrode at the low potential is improved by blending the lithium iron phosphate with the lower reaction potential and cooperating with lithium ion diffusion of the low-cobalt active material at the low potential, thereby improving the energy density of the battery.
The comparative example 1 does not contain lithium iron phosphate, so that a low-potential voltage platform is low and the overall energy density is not high.
And in the comparative example 2, the lithium iron phosphate is too much, so that the voltage platform of the whole electrode is too low, and the energy density is reduced.
Comparative example 3 too little lithium iron phosphate resulted in an insignificant gain in the overall energy density of the cell.
The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. The cathode material is characterized by comprising a low-cobalt active material and lithium iron phosphate, wherein the mass ratio of the low-cobalt active material to the lithium iron phosphate is 90:10-99: 1.
2. The positive electrode material of claim 1, wherein the low cobalt active material has a chemical formula of LiNixCoyM1-x-yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, y is more than or equal to 0 and less than or equal to 0.05, and M is Mn and/or Al;
preferably, M is Mn;
preferably, the low cobalt active material is spherical secondary particles or single crystals;
preferably, the spherical secondary particles have a D50 particle size of 8 to 18 μm;
preferably, the single crystal has a D50 particle size of 2-7 μm.
3. The positive electrode material according to claim 1 or 2, wherein the lithium iron phosphate is spherical micro lithium iron phosphate or nano lithium iron phosphate;
preferably, the D50 particle size of the spherical micron lithium iron phosphate is 5-15 μm;
preferably, the D50 particle size of the nano lithium iron phosphate is 0.5-2 μm.
4. A method for producing the positive electrode material according to any one of claims 1 to 3, characterized by comprising the steps of:
and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio to obtain the cathode material.
5. The method for producing a positive electrode material according to claim 4, wherein the mixing is stirring mixing;
preferably, the stirring and mixing is high-speed stirring and mixing.
6. A pole piece comprising the positive electrode material according to any one of claims 1 to 3.
7. The pole piece according to claim 6, wherein the pole piece comprises a current collector and a coating coated on the current collector, wherein the coating comprises the positive electrode material according to any one of claims 1 to 3;
preferably, the coating further comprises a conductive agent and a binder;
preferably, the conductive agent comprises conductive carbon black and/or conductive carbon nanotubes;
preferably, the binder comprises any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene or styrene butadiene rubber;
preferably, in the coating, the mass ratio of the positive electrode material, the conductive agent and the binder is 100 (1-2) to (0.5-1.5);
preferably, the current collector is an aluminum foil.
8. A method of making a pole piece as claimed in claim 6 or claim 7, comprising the steps of:
mixing the conductive slurry with the positive electrode material according to any one of claims 1 to 3 to obtain positive electrode slurry, coating the positive electrode slurry on a current collector, drying and rolling to obtain the pole piece.
9. The method for preparing the pole piece according to claim 8, wherein the mixing is stirring mixing;
preferably, the stirring and mixing is high-speed stirring and mixing;
preferably, the coating is coating with a doctor blade;
preferably, the temperature of the drying is 100-140 ℃;
preferably, the drying time is 15-25 min;
preferably, after the rolling, the rolled product is cut;
preferably, the conductive paste includes formulated amounts of a conductive agent, a binder, and a solvent;
preferably, the solvent comprises water or a nitrogen methyl pyrrolidone solvent;
preferably, the mass ratio of the solvent to the binder is (35-45): 1.
10. The method for preparing a pole piece according to claim 8 or 9, comprising the following steps:
(1) stirring and mixing the low-cobalt active material and the lithium iron phosphate according to the formula ratio at a high speed to obtain a positive electrode material;
dispersing and stirring the conductive agent, the binder and the solvent according to the formula ratio to obtain conductive slurry;
(2) and (2) stirring and mixing the positive electrode material and the conductive slurry obtained in the step (1) at a high speed to obtain positive electrode slurry, coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying box, drying at 140 ℃ for 15-25min, and then rolling and cutting to obtain the pole piece.
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| CN113517423B (en) | 2023-02-24 |
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