Electrode preparation method, electrode prepared thereby and energy storage device comprising the electrode

Abstract

The present application relates to a kind of electrode preparation method and the electrode and energy storage device comprising the electrode prepared by it, wherein the preparation method includes: (1) preparation electrode film piece, including: (a) mixing, electrode active material, conductive additive, non-fibrillar binder are mixed uniformly, then add fibrillar binder, and the resulting mixture is handled into flocculent or mud shape;Or electrode active material, conductive additive, non-fibrillar binder and fibrillar binder are mixed uniformly, and the resulting mixture is handled into flocculent or mud shape;(b) forming, the flocculent or mud shape product of step (a) is formed into electrode film piece;(2) deposition current collector, including: by physical deposition method on the surface of electrode film piece obtained in step (1) deposition metal layer as current collector.The energy storage device of the present application has improved cycle performance, rate capability and initial coulomb efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemistry, in particular the field of energy storage. Specifically, the present application relates to a method for preparing an electrode, an electrode prepared thereby, and an energy storage device comprising the electrode, such as a lithium-ion secondary battery, a sodium-ion secondary battery, a lithium-sulfur secondary battery, or a capacitor. BACKGROUND

[0002] An electrode is an important component of an electrochemical energy storage device, such as a secondary battery, and its specific capacity and working voltage can have a great impact on the energy of the electrochemical device. As the use of energy storage devices in life becomes more and more widespread, people's demand for high-performance (e.g., good cycle performance and rate performance and higher first coulombic efficiency) energy storage devices is increasing. An electrode is generally prepared by mixing an active material, etc. with a solvent, then coating on a current collector and drying. However, the electrodes prepared by the prior art method still have problems such as low energy density, poor cycle performance and rate performance, and low first coulombic efficiency, which are difficult to meet the increasing demand of people.

[0003] In view of the above problems, those skilled in the art still need to develop a new electrode preparation method, compared with the electrode prepared by the traditional preparation method, the electrode prepared by the method has good cycle performance (including improved first discharge specific capacity and cycle discharge specific capacity, which means higher energy density under the same conditions), rate performance and improved first coulombic efficiency. SUMMARY

[0004] The present application is made in view of the above problems in the prior art.

[0005] In a first aspect, the present application relates to a method for preparing an electrode, comprising:

[0006] (1) preparing an electrode membrane, comprising:

[0007] (a) mixing

[0008] mixing the electrode active material, the conductive additive, the non-fibrillated binder uniformly, then adding the fibrillated binder, and processing the resulting mixture into a flocculent or muddy shape; or

[0009] mixing the electrode active material, the conductive additive, the non-fibrillated binder and the fibrillated binder uniformly, and processing the resulting mixture into a flocculent or muddy shape;

[0010] (b) shaping

[0011] shaping the flocculent or muddy product obtained in step (a) into an electrode membrane;

[0012] (2) depositing a current collector, comprising:

[0013] A metal layer is deposited on one surface of the electrode film obtained in step (1) as a current collector by a physical deposition method.

[0014] The electrode preparation method of the present application does not use solvents such as organic solvents, thereby overcoming some of the defects of conventional electrode preparation methods, which avoid the use of expensive and toxic organic solvents such as N-methyl pyrrolidone, are environmentally friendly and have cost advantages.

[0015] In addition, compared with the electrode prepared by the conventional electrode preparation method (e.g., coating the electrode active material on the current collector), the electrode active material, the conductive additive, the non-fibrillated cellulose and the fibrillated cellulose are mixed and then formed into an electrode film, and then the current collector is deposited on the obtained electrode film, thereby significantly reducing the volume and mass ratio of the sheet-shaped current collector for coating the active material in the energy storage device, and improving the mass specific capacity and volume specific capacity of the energy storage device.

[0016] Further, the inventors surprisingly found that, compared with the conventional electrode obtained by coating the positive and negative active materials on the positive and negative current collectors, in addition to the increase in specific capacity due to the reduction in the mass and volume of the auxiliary components, in the electrode prepared by the method of the present application, the electrode active material has improved first discharge specific capacity and cycle discharge specific capacity, even at an increased charge and discharge rate. This is beneficial to improve the energy density of the energy storage device and improve the cycle performance and rate performance of the energy storage device. In addition, compared with the conventional electrode obtained by coating the positive and negative active materials on the positive and negative current collectors, the energy storage device including the electrode prepared by the method of the present application also has improved first coulombic efficiency.

[0017] In addition, the inventors also unexpectedly found that by adjusting the addition order of the fibrillated binder, the treatment temperature of the electrode film, and / or the temperature of the physical deposition process, etc., the first coulombic efficiency or the discharge specific capacity can be further improved, and / or the peeling force between the current collector and the electrode film can be increased or the impedance of the electrode film can be reduced.

[0018] The electrode prepared by the electrode preparation method of the first aspect of the present application has improved cycle performance (including improved first discharge specific capacity and cycle discharge specific capacity) and rate performance, and higher first coulombic efficiency.

[0019] Alternatively or additionally, the electrode prepared by the electrode preparation method of the first aspect of the present application has improved peeling force between the current collector and the electrode film.

[0020] Alternatively or additionally, the electrode prepared by the electrode preparation method of the first aspect of the present application has reduced impedance.

[0021] In a second aspect, the present application relates to an electrode prepared by the electrode preparation method according to the first aspect of the present application.

[0022] In a third aspect, the present application relates to an energy storage device comprising a positive electrode and a negative electrode, wherein at least one of the positive electrode and the negative electrode, preferably both the positive electrode and the negative electrode, comprise an electrode according to the second aspect of the present application.

[0023] The present application will be described in detail below by way of exemplary embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the present application, the accompanying drawings required for describing the embodiments will be briefly described below. It should be understood that these drawings are only for the convenience of the technicians to more easily understand the present application, and are not intended to limit the scope of the present application.

[0025] Figure 1 Scanning electron microscope picture of the positive electrode film 21 prepared for Example 1.

[0026] Figure 2 Scanning electron microscope picture of the positive electrode film 22 prepared for Example 1.

[0027] Figure 3 Cyclic voltammogram of the CR2032 button half-cell assembled with the negative electrode 1 and the negative electrode 2 prepared for Example 2.

[0028] Figure 4 Galvanostatic first charge-discharge curve of the CR2032 button half-cell assembled with the negative electrode 1 and the negative electrode 2 prepared for Example 2.

[0029] Figure 5 Thermal flow curve of the negative electrode film 6 prepared for Example 4.

[0030] Figure 6 Galvanostatic first charge-discharge curve of the CR2032 button half-cell assembled with the negative electrode 6 and the negative electrode 7 respectively prepared for Example 4.

[0031] Figure 7 Comparison of the first coulombic efficiency of the CR2032 button half-cell assembled with the negative electrode 6 and the negative electrode 7 respectively prepared for Example 4.

[0032] Figure 8 Graph showing the electrochemical impedance (ohm) spectrum of the positive electrode 26, the positive electrode 27 and the positive electrode 28 respectively prepared for Example 5.

[0033] Figure 9To show the graph of the discharge specific capacity (mAh / g) of the negative electrode active material and the entire negative electrode of the negative electrode 11 and the negative electrode 12 each with respect to the cycle number.

[0034] Figure 10 To show the graph of the discharge specific capacity (mAh / g) of the positive electrode active material and the entire positive electrode of the positive electrode 29 and the positive electrode 30 each at different rates with respect to the cycle number.

[0035] Figure 11 To show the graph of the discharge specific capacity (mAh / g) of the entire battery of the secondary battery 1 and the secondary battery 2 with respect to the cycle number.

[0036] Figure 12 To show the graph of the charge-discharge voltage (V) versus the discharge specific capacity (mAh / g) of the entire battery of the secondary battery 1 and the secondary battery 2 in the first charge-discharge cycle. DETAILED DESCRIPTION

[0037] In order to make the purposes, technical solutions and beneficial technical effects of the present application clearer, the present application will be described in detail below. It should be noted that the various aspects, features, embodiments, and advantages described in the present application can be compatible and / or combined together.

[0038] Unless otherwise specified, the meanings of the scientific and technical terms in the present specification are the same as those generally understood by those skilled in the art.

[0039] The present application relates to an electrode preparation method and an electrode prepared thereby, and an energy storage device, such as a lithium ion secondary battery, a sodium ion secondary battery, a lithium-sulfur secondary battery, or a capacitor, a supercapacitor, a lithium ion capacitor, comprising the electrode.

[0040] The present application will be described in detail below.

[0041] Electrode preparation method

[0042] In a first aspect, the present application relates to an electrode preparation method, comprising:

[0043] (1) preparing an electrode film, comprising:

[0044] (a) mixing

[0045] mixing the electrode active material, the conductive additive, and the non-fibrillated binder uniformly, then adding the fibrillated binder, and processing the resulting mixture into a flocculent or muddy state; or

[0046] mixing the electrode active material, the conductive additive, the non-fibrillated binder, and the fibrillated binder uniformly, and processing the resulting mixture into a flocculent or muddy state;

[0047] (b) forming

[0048] forming the flocculent or muddy product obtained in step (a) into an electrode sheet;

[0049] (2) depositing a current collector, comprising:

[0050] depositing a metal layer as a current collector on one surface of the electrode sheet obtained in step (1) by a physical deposition method.

[0051] The electrode preparation method of the present application does not use solvents such as organic solvents, thereby overcoming some defects of conventional electrode preparation methods, which avoid the use of expensive and toxic organic solvents such as N-methyl pyrrolidone, are environmentally friendly and have cost advantages.

[0052] In addition, compared with the electrode prepared by the conventional electrode preparation method (e.g. coating the electrode active material on the current collector), the electrode active material, the conductive additive, the non-fibrillated cellulose and the fibrillated cellulose are mixed and then formed into an electrode sheet, and then the current collector is deposited on the obtained electrode sheet, thereby significantly reducing the volume and mass ratio of the sheet-shaped current collector for coating the active material in the energy storage device, and improving the mass specific capacity and volume specific capacity of the energy storage device.

[0053] Further, the inventors surprisingly found that, compared with the conventional electrode obtained by coating the positive and negative active materials on the positive and negative current collectors, in addition to the increase in specific capacity due to the reduction in the mass and volume of the auxiliary components, in the electrode prepared by the method of the present application, the electrode active material has improved first discharge specific capacity and cycle discharge specific capacity, even at an increased charge-discharge rate. This is beneficial to improve the energy density of the energy storage device and improve the cycle performance and rate performance of the energy storage device. In addition, compared with the conventional electrode obtained by coating the positive and negative active materials on the positive and negative current collectors, the energy storage device comprising the electrode prepared by the method of the present application also has improved first coulombic efficiency.

[0054] In addition, the inventors also unexpectedly found that by adjusting the addition order of the fibrillated binder, the treatment temperature of the electrode sheet, and / or the temperature of the physical deposition process, etc., the first coulombic efficiency or the discharge specific capacity can be further improved, and / or the peeling force between the current collector and the electrode sheet can be increased or the impedance of the electrode sheet can be reduced.

[0055] The electrode preparation method of the present application comprises preparing an electrode sheet and depositing a current collector. Each step will be described in detail below.

[0056] Preparation of an electrode sheet

[0057] The preparation of the electrode film includes a mixing and a shaping step.

[0058] It is noted that the term "electrode film" refers to a film (i.e. active material layer) prepared from a mixture of electrode active material, conductive additive, binder, etc., and does not include a current collector. In contrast, the term "electrode" or "electrode sheet" includes not only the "electrode film" but also the "current collector".

[0059] Mixing

[0060] The purpose of the mixing process is to obtain a mixture of electrode active material, conductive additive, non-fibrillated binder, and optional fibrillated binder, to facilitate the subsequent steps.

[0061] In some embodiments, the mixing process mixes the electrode active material, conductive additive, non-fibrillated binder, and fibrillated binder uniformly, and processes the resulting mixture into a flocculent or muddy state.

[0062] The inventors have found in their research that the addition of non-fibrillated binder helps to alleviate the stress during the rolling process, to avoid the particles from being pressed into a hard and brittle mass, and thus to avoid cracks on the surface of the electrode film. In addition, the inventors have also unexpectedly found that the addition of non-fibrillated binder can significantly reduce the electrode side reactions and improve the initial coulombic efficiency.

[0063] In contrast to the non-fibrillated binder, the addition of fibrillated binder can perform a fibrillation process to process the resulting mixture into a flocculent or muddy state. In this context, the term "fibrillation" refers to the "fibrillated binder" originally in a granular state being stretched into a fibrous state under the action of mechanical shear force, and being entangled with the electrode active material and conductive additive, etc., to form a three-dimensional network. The inventors have also unexpectedly found in their research that the order of addition of the fibrillated binder during the mixing process can have a significant impact on the initial coulombic efficiency and the discharge specific capacity, such as the initial discharge specific capacity. Specifically, the later the order of addition of the fibrillated binder during the mixing process, the higher the initial coulombic efficiency and the discharge specific capacity, such as the initial discharge specific capacity, of the corresponding energy storage device, such as a secondary battery, such as a lithium-ion secondary battery.

[0064] Therefore, in preferred embodiments, the mixing process mixes the electrode active material, conductive additive, and non-fibrillated binder uniformly, then adds the fibrillated binder, and processes the resulting mixture into a flocculent or muddy state.

[0065] It is to be noted that the term "fibrillated binder" refers to a binder component that is subjected to shear force during the electrode film preparation process, and as a result, the structure slips and extends into a fiber network having a winding and coating function in the electrode structure. In contrast, the term "non-fibrillated binder" refers to a binder component that is dissolved / melted by a solvent or heat, thereby forming a coating within the electrode, and achieving adhesion using interaction forces (including van der Waals forces, hydrogen bonds, covalent interactions, etc.) with each component of the electrode. Thus, the "fibrillated binder" is different from the "non-fibrillated binder".

[0066] The preparation method of the present application does not have a particular requirement for the type of non-fibrillated binder, and any type of non-fibrillated binder commonly used in the art can be used. As an example, the non-fibrillated binder is selected from one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyacrylic acid, sodium alginate, poly(ethylene oxide), polyacrylonitrile (PAN), polyvinyl alcohol, polyimide (PI), cellulose, and cellulose derivatives (e.g., cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), nitrocellulose, carboxymethyl cellulose (CMC), carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium cellulose, sodium nitrocellulose, and sodium carboxyalkyl cellulose), preferably one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyacrylic acid, and sodium alginate.

[0067] Similarly, the preparation method of the present application does not have a particular requirement for the type of fibrillated binder, and any type of fibrillated binder commonly used in the art can be used. As an example, the fibrillated binder is selected from polytetrafluoroethylene. Preferably, the volume average particle diameter D v 50is in the range of 0.1-1000 μm, preferably 200-600 μm. v 50Particle diameter refers to a value at which the particles (e.g., fibrillated binder) each occupying 50% of the total sample volume are present in the volume cumulative distribution curve of the particles (e.g., fibrillated binder) less than the particle diameter value and greater than the particle diameter value. The D v 50Particle diameter can be measured by a method commonly used by those skilled in the art. As an example, a laser particle size analyzer can be used.

[0068] Similarly, the preparation method of the present application does not have a particular requirement for the type of conductive additive, and any conductive additive commonly used in the art can be used. As an example, the conductive additive can be selected from one or more of graphite, superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0069] As will be readily appreciated by those skilled in the art, in addition to the electrode active material, the electrically conductive additive, the non-fibrillar binder and the fibrillar binder, other commonly used materials for electrode preparation, such as thickening agents, film formation promoters, etc., can be added during the mixing process.

[0070] In some embodiments, the weight ratio of the amount of the fibrillar binder added to the amount of the non-fibrillar binder added is in the range of 0.1:1 to 10:1, preferably 0.1:1 to 3.0:1, based on the total weight of all components subjected to mixing, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 4.0:1, 5.0:1, 6.0:1, 8.0:1, 10.0:1, or a range defined by any two of them. When the amount of the fibrillar binder added to the amount of the non-fibrillar binder added is in the above range, it is advantageous for the fibrillar binder and the non-fibrillar binder to better play a synergistic role, thereby being advantageous for improving the cycle performance (including the initial discharge capacity and the cycle discharge capacity), the rate capability and the initial coulombic efficiency.

[0071] In some embodiments, the electrode active material is added in an amount of 80-98 wt.%, preferably 90-98 wt.%, based on the total weight of all components being mixed; the electrically conductive additive is added in an amount of 0.5-10 wt.%; the non-fibrillated binder is added in an amount of 0.5-10 wt.%, preferably 1-8 wt.%; and the fibrillated binder is added in an amount of 0.5-10 wt.%, preferably 1-5 wt.%. Those skilled in the art will readily appreciate that the total weight of all components being mixed is 100%. By way of example, the fibrillated binder can be added in an amount of 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, 2.5 wt.%, 3.0 wt.%, 3.5 wt.%, 4.0 wt.%, 4.5 wt.%, 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.%, 10.0 wt.%, or within a range defined by any two of them, and / or the non-fibrillated binder can be added in an amount of 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, 2.5 wt.%, 3.0 wt.%, 3.5 wt.%, 4.0 wt.%, 4.5 wt.%, 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.%, 10.0 wt.%, or within a range defined by any two of them, based on the total weight of all components being mixed.

[0072] In some embodiments, the total amount of the non-fibrillated binder and the fibrillated binder is 1-15 wt.%, preferably 1-10 wt.%, based on the total weight of all components being mixed. For example, the total amount of the non-fibrillated binder and the fibrillated binder can be 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, 2.5 wt.%, 3.0 wt.%, 3.5 wt.%, 4.0 wt.%, 4.5 wt.%, 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.%, 10.0 wt.%, 10.5 wt.%, 11.0 wt.%, 11.5 wt.%, 12.0 wt.%, 12.5 wt.%, 13.0 wt.%, 13.5 wt.%, 14.0 wt.%, 14.5 wt.%, 15.0 wt.%, or within a range defined by any two of them, based on the total weight of all components being mixed.

[0073] For the content of each of the above components, those skilled in the art will readily appreciate that, after the electrode membrane is prepared, the content of each of the above components is also within the above range, based on the dry weight of the electrode membrane.

[0074] The electrode preparation method of the present application does not have a special requirement for the mixing method, and a mixing method commonly used in the art can be used, for example, the mixture can be mixed by one or more of ball milling, jet milling, high-speed shearing machine or mechanical grinding. As an example, a person skilled in the art can mix by a planetary ball mill or mechanical stirring. For example, when mixing by mechanical stirring, the rotation speed of the mechanical stirring can be controlled to be 50-10000 rpm, for example, 50 rpm, 100 rpm, 300 rpm, 500 rpm, 1000 rpm, 2000 rpm, 3000 rpm, 5000 rpm, 8000 rpm, 10000 rpm, or a range defined by any two of them, and / or the mixing time is 5-720 minutes, for example, 5 minutes, 30 minutes, 60 minutes, 120 minutes, 240 minutes, 300 minutes, 360 minutes, 420 minutes, 720 minutes, or a range defined by any two of them. In addition, for example, zirconium oxide can be used as a ball milling medium, and the volume fraction of zirconium oxide is less than 30%. A person skilled in the art can easily understand that the flocculation or mud processing of the mixture added with the fibrillated binder can also be carried out by one or more of ball milling, jet milling (i.e. air flow milling or energy flow milling), high-speed shearing machine, or mechanical grinding. Therefore, preferably, in the embodiments, the mixture added with the fibrillated binder is processed into flocculation or mud while being mixed.

[0075] Molding

[0076] The molding method of the flocculation or mud product of the present application is not particularly limited, and a technical means commonly used by a person skilled in the art can be used. As an example, the flocculation or mud product can be molded into an electrode film by one or more of roll pressing (e.g. hot roll molding), extrusion molding, injection molding, blow molding, coating molding, or casting molding, preferably roll pressing (e.g. hot roll molding), extrusion molding. Hot roll molding refers to the molding of the fibrillated electrode material by a hot roll press multiple times. During the roll pressing process, the flocculation or mud powder is molded, and with the increase of the pressure and the number of times, the thickness of the electrode film is continuously thinned, and the compacted density is continuously improved. Heating can improve the flowability of the polymer, improve the processability of the electrode film, and on the other hand, can also make the non-fibrillated binder melt and uniformly coat and bond the other components of the electrode film, so as to achieve a closer adhesion between the components of the electrode film. As an example, during the hot roll molding process, the roll pressing pressure can be controlled to be 0.1×10 3 -20.0×10 3 kgf / cm 2 , the roll pressing temperature is 10-200℃, the roll pressing speed is 0.5-50 m / min, and the roll pressing number is 1-30 times. As an example, the roll pressing pressure can be 0.1×10 30.2 x 10 3 0.3 x 10 3 0.5 x 10 3 0.8 x 10 3 1.0 x 10 3 2.0 x 10 3 5.0 x 10 3 10.0 x 10 3 15.0 x 10 3 20.0 x 10 3 kgf / cm 2 or any two of them, and / or the roll temperature can be in the range of 10, 20, 30, 40, 50, 60, 70, 80, 100, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 °C, or any two of them.

[0077] In some embodiments, preferably, there is no pre-forming step before step (b) is performed. Not performing a pre-forming step facilitates batch production of the electrode film, simplifies the process, and improves production efficiency.

[0078] In some embodiments, after the electrode film sheet is prepared, the resulting electrode film sheet is kept at a temperature of 100-250 °C, preferably 150-200 °C, preferably in vacuum, for 4-20 h, preferably 8-16 h. By subjecting the electrode film sheet to the above heat treatment, the initial coulombic efficiency can be improved. This is believed to be due to the fact that the above heat treatment helps to reduce side reactions of the electrode during charge and discharge. By way of example, the temperature at which the resulting electrode film sheet is treated can be in the range of 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 °C, or any two of them, and / or the treatment time can be in the range of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 h, or any two of them.

[0079] In some embodiments, the thickness of the electrode film produced in the forming step is 10-1000 μm, preferably 50-200 μm. By way of example, the thickness of the electrode film produced in the forming step can be 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 μm, or a range defined by any two of them.

[0080] depositing a current collector

[0081] After the electrode film is produced, a metal layer is deposited on one surface of the resulting electrode film as a current collector by a physical deposition method, thereby obtaining an electrode.

[0082] In some embodiments, before the current collector is deposited on the electrode film by the physical deposition method, a patterned mask is applied to the surface of the electrode film on which the current collector is to be deposited. For example, the patterned mask can be selected from a rectangle, a triangle, a ring, and the like. The application of the patterned mask is advantageous in reducing the amount of the deposited current collector, saving cost; and a good current conduction function can be maintained even with a reduced deposition amount by the design of the mask pattern.

[0083] In some embodiments, before the current collector is deposited on the electrode film by the physical deposition method, a pretreatment step is performed on the electrode film, which is selected from at least one of the following: plasma cleaning and surface etching.

[0084] In some embodiments, the electrode film is pretreated by plasma. For example, a vacuum or non-vacuum plasma cleaning can be performed, and oxygen, helium, argon or xenon can be used as the process gas.

[0085] In some embodiments, the electrode film is pretreated by surface etching. For example, oxygen can be used as the etchant, and the etching time is for example 1-20 min, preferably 1-10 min.

[0086] In the present application, the current collector is deposited on one surface of the electrode film by a physical deposition method. By way of example, the physical deposition method (physical vapor deposition method) can be selected from one or more of sputter plating (e.g. magnetron sputtering), evaporation plating or ion plating.

[0087] In some embodiments, the physical deposition method is magnetron sputtering. For example, the target material of the magnetron sputtering is selected from a metallic material, such as one or more of the elements or alloys selected from copper, aluminum, nickel, titanium, tin, iron, gold, platinum. The process conditions of the magnetron sputtering are as follows: the substrate temperature is 10-300°C, preferably 20-200°C, the substrate (i.e. the electrode membrane) rotation speed is 0-20 rpm, the target-substrate distance is 50-200 mm; the main chamber vacuum is 5x10 -3 -5x10 -6 Pa, the process gas pressure is 0.5-15 Pa, the power supply power is 20-500 W, and the sputtering time is 20-5000 s. The inventors have found that by adjusting the substrate temperature during the magnetron sputtering process, it is possible to improve the peel strength between the current collector and the electrode membrane and reduce the impedance. As an example, the substrate temperature during the magnetron sputtering process can be 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 °C, or a range defined by any two of them.

[0088] In some embodiments, the thickness of the current collector prepared by the electrode preparation method of the present application is 0.1-10 μm, preferably 0.5-2 μm. As an example, the thickness of the current collector can be 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0 μm, or a range defined by any two of them.

[0089] In some embodiments, the ratio of the thickness of the current collector to the thickness of the electrode membrane prepared by the method of the present application is in the range of 0.0001:1 to 0.1000:1, preferably 0.005:1 to 0.0300:1. As an example, the ratio of the thickness of the current collector to the thickness of the electrode membrane can be 0.0001:1, 0.0050:1, 0.0100:1, 0.0200:1, 0.0300:1, 0.0400:1, 0.0500:1, 0.0600:1, 0.0700:1, 0.0800:1, 0.0900:1, 0.1000:1, or a range defined by any two of them.

[0090] Electrode

[0091] The second aspect of the present application provides an electrode prepared by the electrode preparation method according to the first aspect of the present application.

[0092] Energy storage device

[0093] The third aspect of the present application provides an energy storage device comprising a positive electrode and a negative electrode, wherein at least one of the positive electrode and the negative electrode, preferably both the positive electrode and the negative electrode, comprise an electrode according to the second aspect of the present application.

[0094] In some embodiments, the energy storage device is a lithium-ion secondary battery, a sodium-ion secondary battery, a lithium-sulfur secondary battery, or a capacitor, a supercapacitor, a lithium-ion capacitor, preferably a lithium-ion secondary battery, a sodium-ion secondary battery.

[0095] The energy storage device of the present application is described below by way of example of a lithium-ion secondary battery. It is readily understood by the person skilled in the art that the description with respect to a lithium-ion secondary battery can be adapted to obtain a sodium-ion secondary battery, a lithium-sulfur secondary battery, or a capacitor, a supercapacitor, a lithium-ion capacitor of the present application.

[0096] Lithium-ion secondary battery

[0097] In some embodiments, the energy storage device of the present application is a lithium-ion secondary battery.

[0098] The present application does not particularly require the type of the positive electrode active material of the lithium-ion secondary battery, and any positive electrode active material commonly used in the art can be employed. In some embodiments, the positive electrode active material is selected from one or more of, for example, lithium transition metal complex oxides, complex oxides obtained by adding other transition metals or non-transition metals or non-metals to the lithium transition metal complex oxides. In some embodiments, the layered transition metal oxide can have a general formula Li x M y O2, wherein M is selected from one or more of Mn, Fe, Ni, Co, Cr, Ti, Zn, V, Al, Zr, Ce and Mg, the general formula satisfying the valence balance. In addition, the layered transition metal oxide can also be doped with an element having a large electronegativity, such as one or more of S, N, F, Br, Cl, I, CN, etc. For example, the positive electrode active material can be selected from one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, lithium-containing phosphates of olivine structure, such as LiFeMnPO4, LiCoO2, LiMn2O4, LiNiMnCoO2, LiNi 0.5 Co 0.3 Mn 0.2 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2O2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiFePO4, LiNiCoAlO2, and Li2TiO, etc.

[0099] In some embodiments, the amount of the positive active material is 80-98 wt%, preferably 90-98 wt%, based on the dry weight of the positive electrode sheet.

[0100] In some embodiments, any negative active material commonly used by those skilled in the art can be employed. For example, the negative active material can be one or more of natural graphite, artificial graphite, meso-carbon microbe (MCMB), hard carbon, soft carbon, silicon-based material, tin-based material, lithium titanate, and metallic sodium, preferably one or more of graphite and silicon-based material, more preferably one or more of graphite, silicon-carbon composite, and silicon alloy.

[0101] In some embodiments, the amount of the negative active material is 80-98 wt%, preferably 90-98 wt%, based on the dry weight of the negative electrode sheet.

[0102] Those skilled in the art will readily understand that, when the energy storage device of the present application is a secondary battery, the secondary battery further comprises an electrolyte.

[0103] In some embodiments, the electrolyte is a non-aqueous liquid electrolyte. The present application does not particularly require the kind of the non-aqueous liquid electrolyte. The non-aqueous liquid electrolyte comprises a non-aqueous organic solvent and an electrolyte lithium salt.

[0104] In some embodiments, the non-aqueous organic solvent can be selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), vinylene carbonate (VC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0105] In some embodiments, the electrolyte lithium salt can be selected from one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroborate (LiBF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethylsulfonylimide (LiTFSI), lithium trifluoromethylsulfonate (LiTFS), lithium difluoro-oxalato-borate (LiDFOB), lithium bis-oxalato-borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluoro-di-oxalato-phosphate (LiDFOP), and lithium tetrafluoro-oxalato-phosphate (LiTFOP).

[0106] In some embodiments, the concentration of lithium ions in the non-aqueous liquid electrolyte is 0.5 to 1.5 mol / L, for example, 0.8-1.2 mol / L.

[0107] In some embodiments, the non-aqueous liquid electrolyte also optionally includes an additive. As an example, the additive can include an additive that facilitates negative electrode film formation or an additive that facilitates positive electrode film formation, and can also include an additive that improves battery performance, for example, an additive that improves battery performance at high or low temperatures, etc.

[0108] As will be readily understood by one skilled in the art, when the electrolyte is a liquid electrolyte, the lithium ion secondary battery also includes a porous separator. The present application does not have a particular limitation on the porous separator used, and a commonly used porous separator having electrochemical stability and chemical stability can be used, for example, it can be a single layer or a multi-layer film of one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, for example, a PP / PE / PP three-layer porous film. When a solid electrolyte is used, the separator can also be omitted.

[0109] In some embodiments, the electrolyte is a gel electrolyte. The present application does not have a particular requirement for the type of gel electrolyte, and any gel electrolyte conventionally used in the art can be used. In some embodiments, the gel electrolyte can include a polymer matrix, and a liquid electrolyte including a lithium salt and a non-aqueous organic solvent. The polymer matrix can be selected from one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer P(VDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). The liquid electrolyte can be the same as described above.

[0110] Similarly, as will be readily understood by one skilled in the art, when the electrolyte is a gel electrolyte, a porous separator can also be optionally included. The gel electrolyte can be at least partially filled in the pores of the porous separator. The description of the porous separator is the same as that of the porous separator used with the liquid electrolyte.

[0111] In some embodiments, the electrolyte is a solid-state electrolyte. The present application does not have a particular requirement for the type of solid-state electrolyte, and any solid-state electrolyte conventionally used in the art can be used. The solid-state electrolyte can be selected from one or more of inorganic solid-state electrolytes or polymer electrolytes, preferably one or more of oxides, sulfides and polymers. For example, the solid-state electrolyte can be selected from one or more of lithium garnet oxide (Li7La3Zr2O12, abbreviated as LLZO), tin oxide (SnO2), bismuth oxide (Bi2O3), lithium sulfide (Li2S), sodium sulfide (Na2S), silicates, phosphates, siloxanes, perovskite oxides, lithium oxides and polymer solid-state electrolytes, etc. 12

[0112] The above describes the energy storage device of the present application by taking a lithium-ion secondary battery as an example. It is easy for those skilled in the art to understand that the energy storage device of the present application can also be a sodium-ion secondary battery, a lithium-sulfur secondary battery or a capacitor (e.g. a supercapacitor, a lithium-ion capacitor), and those skilled in the art can refer to the above-described lithium-ion secondary battery and make appropriate adjustments to obtain the sodium-ion secondary battery, the lithium-sulfur secondary battery or the capacitor (e.g. the supercapacitor, the lithium-ion capacitor) of the present application.

[0113] In some embodiments, the energy storage device of the present application is a sodium-ion secondary battery. When the energy storage device is a sodium-ion secondary battery, the positive electrode active material is selected from one or more of layered transition metal oxides or Prussian blue analogues, preferably Na2FeFe(CN)6(NaHCF), NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, Na2FeP2O7, Na4Fe3(PO4)2(P2O7), Na3V2(PO4)3, NaFePO4 and NaMnFe(CN)6, etc., preferably the amount of the positive electrode active material is 80-98 wt.%, preferably 90-98 wt.%, based on the dry weight of the positive electrode film; and / or

[0114] The negative electrode active material is selected from one or more of natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon-based materials, tin-based materials, preferably one or more of graphite and silicon-based materials, more preferably one or more of graphite, silicon-carbon composite, silicon alloy, preferably the amount of the negative electrode active material is 80-98 wt.%, preferably 90-98 wt.%, based on the dry weight of the negative electrode film.

[0115] ​In some embodiments, the energy storage device of the present application is a lithium-sulfur secondary battery. When the energy storage device is a lithium-sulfur secondary battery, the positive electrode active material is selected from one or more of inorganic compounds such as lithium sulfide, titanium sulfide, phosphorus sulfide, or organic compounds having one or more of straight-chain alkyl, branched-chain alkyl, cycloalkane, arene, heteroatom-containing arene, sulfur-combined compounds, preferably one or more of sulfur-carbon composite positive electrode materials, sulfurized polyacrylonitrile, preferably, the amount of the positive electrode active material is 80-98 wt.%, preferably 90-98 wt.%, based on the dry weight of the positive electrode film; and / or

[0116] The negative electrode active material can be a negative electrode active material commonly used in lithium-sulfur secondary batteries, for example, selected from metal lithium, preferably, the amount of the negative electrode active material is 80-99 wt.%, preferably 90-99 wt.%, based on the dry weight of the electrode film.

[0117] In some embodiments, the energy storage device of the present application is a capacitor. When the energy storage device is a capacitor, the positive electrode active material is selected from one or more of metal oxides, conductive polymers, carbon materials, preferably one or more of MnO2, NiO, Co3O4, polyaniline, polypyrrole, activated carbon, graphene, biochar, preferably, the amount of the positive electrode active material is 80-98 wt.%, preferably 90-98 wt.%, based on the dry weight of the positive electrode film; and / or

[0118] The negative electrode active material is selected from one or more of metals, carbon materials, conductive polymers, metal oxides, metal-organic framework (MOF) derived materials, preferably one or more of aluminum, zinc, activated carbon, graphite, polyaniline, polypyrrole, polythiophene, MnO2, preferably, the amount of the negative electrode active material is 80-98 wt.%, preferably 90-98 wt.%, based on the dry weight of the negative electrode film.

[0119] For supercapacitors or lithium-ion capacitors, those skilled in the art can refer to the above embodiments and make appropriate adjustments.

[0120] Example

[0121] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0122] I. Measurement method

[0123] 1. Scanning electron microscope test

[0124] The prepared electrode film was fixed on the sample stage and sent into the sample chamber of the scanning electron microscope (Zeiss Gemini) to observe the surface morphology of the electrode film.

[0125] 2. Volume average particle size D v 50

[0126] The sample to be tested was added to an appropriate amount of ethanol solvent to make the concentration of the sample to be tested 0.01 g / L, and ultrasonic dispersion was formed into a dispersion liquid. Then a Mastor 2000 laser particle size analyzer was used for testing to obtain the equivalent particle size distribution information.

[0127] 3. Peeling force

[0128] The active material side of the composite electrode to be tested was fixed on a horizontally placed substrate, and a test tape was attached on the current collector side. The tape and the substrate were fixed on a universal testing machine ZWICKZ020 through clamps, respectively, with both ends at 180°. The stretching started at a rate of 5 cm / min, i.e. the current collector peeling on the electrode surface, and the peeling force and displacement information were recorded.

[0129] 4. Thermal performance test

[0130] Differential scanning calorimetry (DSC) was used for testing, and the heat absorption and release information of the electrode film during the heating process was recorded to characterize the phase transition of the non-fibrillated binder during the heat treatment. The test conditions are as follows: using Q5000IR instrument, the atmosphere is argon, and the temperature is raised from 20°C to 300°C at a rate of 10°C / min. The signal recorded during the heating process is taken as the measurement result.

[0131] 5. Electrode electrochemical performance test

[0132] 5.1 Cyclic voltammetry curve

[0133] Cyclic voltammetry test was performed using an electrochemical workstation (CHI660e, Chenhua). The voltage range was 0.005V-2V. The cyclic voltammetry curve was measured at a scan rate of 1mV s-1. During the measurement, the voltage was first reduced from 2V to 0.005V, and then increased from 0.005V to 2V.

[0134] 5.2 Impedance

[0135] Electrochemical impedance was measured using CHI660e of Chenhua. The electrochemical impedance measurement conditions were: frequency range 100kHz to 0.01Hz, and alternating current voltage amplitude 10mV.

[0136] 5.3 Battery charge and discharge test

[0137] Battery cycle data was collected at room temperature using a battery tester (LAND, 2001CT).

[0138] 5.3.1 Lithium-ion battery charge-discharge test

[0139] Half-cell charge-discharge test

[0140] The negative half-cell charge-discharge test condition is: at a temperature of 30°C, the CR2032 button half-cell is charged to 1.5V at a current of 0.5C rate, then stands for 5min, then discharged to 0.005V at a current of 0.5C rate, then stands for 5min, which is a charge-discharge cycle. The discharge capacity and charge capacity at the first charge-discharge cycle are recorded as the first discharge capacity (i.e. the delithiation capacity, the same below) and the first charge capacity (i.e. the lithiation capacity, the same below). Similarly, the discharge capacity and charge capacity at the n-th cycle are recorded as the n-th discharge capacity and the n-th charge capacity, respectively.

[0141] The positive half-cell charge-discharge test condition is: at a temperature of 30°C, the CR2032 button half-cell is charged to 4.3V at a current of 0.5C rate, then stands for 5min, then discharged to 3.0V at a current of 0.5C rate, then stands for 5min, which is a charge-discharge cycle. The discharge capacity and charge capacity at the first charge-discharge cycle are recorded as the first discharge capacity and the first charge capacity. Similarly, the discharge capacity and charge capacity at the n-th cycle are recorded as the n-th discharge capacity and the n-th charge capacity, respectively.

[0142] Full-cell charge-discharge test:

[0143] The full-cell charge-discharge test condition of the assembled full cell is: at a temperature of 30°C, the battery is charged to 4.3V at a current of 0.5C rate, then stands for 5min, then discharged to 3.0V at a current of 0.5C rate, then stands for 5min, which is a charge-discharge cycle. The discharge capacity and charge capacity at the first charge-discharge cycle are recorded as the first discharge capacity and the first charge capacity. Similarly, the discharge capacity and charge capacity at the n-th cycle are recorded as the n-th discharge capacity and the n-th charge capacity, respectively.

[0144] The discharge capacity measured for the negative half-cell is divided by the mass of the negative electrode, i.e. the discharge gram capacity of the whole negative electrode; the discharge capacity measured is divided by the mass of the negative active material, i.e. the discharge gram capacity of the negative active material.

[0145] Similarly, the discharge capacity measured for the positive half-cell is divided by the mass of the positive electrode, i.e. the discharge gram capacity of the whole positive electrode; the discharge capacity of the positive active material obtained is divided by the mass of the positive active material, i.e. the discharge gram capacity of the positive active material.

[0146] Similarly, the discharge capacity measured for the full cell is divided by the mass of the positive electrode, i.e. the discharge specific capacity (discharge gram capacity) of the positive electrode tab is obtained.

[0147] In the above test, the first discharge capacity is divided by the first charge capacity, and then multiplied by 100% to obtain the first coulombic efficiency.

[0148] In the above test, the percentage of the residual capacity of the nth cycle is the charge capacity at the nth cycle divided by the first charge capacity, and then multiplied by 100%.

[0149] 5.3.2 Sodium-ion secondary battery charge-discharge test

[0150] The charge-discharge test conditions of the assembled battery are as follows: at a temperature of 30°C, the battery is charged to 4V at a current of 0.5C rate, then rested for 5min, then discharged to 2V at a current of 0.5C, then rested for 5min, which is one charge-discharge cycle. The discharge capacity and charge capacity at the first charge-discharge cycle are recorded as the first discharge capacity and the first charge capacity.

[0151] 5.4 Super capacitor capacitance test

[0152] The capacitance of the super capacitor is tested according to the national standard GBT34870.1-2017.

[0153] II. Examples

[0154] Example 1: Effect of the addition of non-fibrillated binder on the processing molding

[0155] NCM523, conductive carbon black (TIMCAL Super P Li, same below), polytetrafluoroethylene (Chemours 601X, same below) (fibrillated binder), sodium carboxymethyl cellulose (DAICEL CMC2200, same below) (non-fibrillated binder) are mixed in a mass ratio of 85:5:5:5, and ball milled (ball milling conditions: zirconium oxide grinding balls, volume ratio less than 30%, unless otherwise specified, the ball milling conditions in other examples are the same as this) at a speed of 100 rpm for 30 min to mix uniformly. The obtained mixture after ball milling is in a flocculent or muddy state. Then roll extrusion (pressure 500 kgf / cm 2 ) at 180°C until the thickness is 80μm, named as positive electrode film 21.

[0156] The positive electrode film 22 does not use non-fibrillated binder, i.e. the ratio of NCM523, conductive carbon black, polytetrafluoroethylene is 85:5:10, and the other preparation process is consistent with that of the positive electrode film 21.

[0157] As Figure 1 and Figure 2As shown, in the absence of non-fibrillated binders, the positive electrode particles are compressed, agglomerated, and broken, resulting in a hard and brittle electrode film surface with cracks. This may be because non-fibrillated binders help relieve stress during the rolling process.

[0158] Example 2: Effect of adding non-fibrillated binder on electrochemical performance

[0159] Graphite (S360-L2-H), conductive carbon black (TIMCAL SuperP Li), polytetrafluoroethylene (MSK-F104) (fibrillated binder), and polyvinylidene fluoride (HSV900) (non-fibrillated binder) were mixed in a mass ratio of 85:5:5:5 and ball-milled at 300 rpm for 30 minutes until homogeneous. The resulting mixture was flocculent or muddy. It was then extruded by rollers at 180°C (pressure 800 kgf / cm²). 2 Until the thickness reaches 60 μm, it is named negative electrode film 1.

[0160] The negative electrode membrane 2 does not use a non-fibrillated binder, i.e., the ratio is graphite: conductive carbon black: polytetrafluoroethylene = 85: 5: 10, and the other preparation processes are consistent with those of the negative electrode membrane 1.

[0161] Two 2 μm thick copper metal layers were deposited on the surfaces of two negative electrode films using magnetron sputtering, resulting in negative electrode 1 and negative electrode 2, respectively. The magnetron sputtering conditions were: substrate temperature 30℃, substrate rotation speed 0 rpm, target-substrate distance 80 mm, and main cavity vacuum of 8 × 10⁻⁶. -4 The process gas (argon) pressure is 0.5 Pa, the power supply is 120 W, and the sputtering time is 2500 s.

[0162] After depositing the copper metal layer, the cells were sliced ​​and vacuum dried. They were then transferred to a glove box and assembled into CR2032 button half-cells under an argon atmosphere. The counter electrode was a 450 μm thick lithium sheet. The electrolyte was a solution of 50 μL of 1M LiPF6 in ethylene carbonate (EC): diethyl carbonate (DEC) = 1:1 (with 10% fluoroethylene carbonate (FEC) and 1% vinylene carbonate (VC) added based on the total volume fraction of EC+DEC). The separator was Celgard 2500 with a thickness of 30 μm.

[0163] like Figure 3 As shown, the reduction peak of negative electrode 2 (from the irreversible decomposition of polytetrafluoroethylene) is particularly significant in the voltage range of 0.4-0.9V. In contrast, negative electrode 1 shows a significantly reduced electrode side reaction when a non-fibrillated binder is added.

[0164] Figure 4Constant current first charge-discharge curves of CR2032 button half-cells assembled with negative electrode 1 and negative electrode 2 prepared in Example 2 are described. Negative electrode 1 improves the first coulombic efficiency from 68% to 80% compared to negative electrode 2.

[0165] Example 3: Effect of fibrillated binder addition sequence

[0166] Negative electrode sheet 3, negative electrode sheet 4 and negative electrode sheet 5 were prepared with a mass ratio of silicon carbon (Timrex 950K): conductive carbon black (TIMCAL C45): polytetrafluoroethylene (MSK-F104) (fibrillated binder): sodium alginate (Timrex) (non-fibrillated binder) of 93:2:2.5:2.5.

[0167] Negative electrode sheet 3 was prepared by first mixing silicon carbon, conductive carbon black and sodium alginate at 8000 rpm for 30 min, followed by adding polytetrafluoroethylene and repeating once. The resulting mixture was flocculent or muddy. Negative electrode sheet 4 was prepared by mixing silicon carbon, conductive carbon black, polytetrafluoroethylene and sodium alginate at 8000 rpm for 30 min. The resulting mixture was flocculent or muddy. Negative electrode sheet 5 was prepared by first mixing silicon carbon, conductive carbon black and polytetrafluoroethylene at 8000 rpm for 30 min, followed by adding sodium alginate and repeating once. The resulting mixture was flocculent or muddy.

[0168] The shaping of negative electrode sheet 3, negative electrode sheet 4 and negative electrode sheet 5, followed by magnetron sputtering and half-cell assembly were the same as in Example 2. The first coulombic efficiency and discharge specific capacity of the half-cells corresponding to negative electrode sheet 3, negative electrode sheet 4 and negative electrode sheet 5 are summarized in Table 1.

[0169] Table 1 Electrochemical performance of half-cells corresponding to negative electrode sheet 3-5

[0170]

[0171] As can be seen from Table 1, the later the addition of fibrillated binder such as polytetrafluoroethylene during the mixing process, the better the electrochemical performance of the corresponding electrode. Without wishing to be bound by any theory, this can be because the fibrillation process of fibrillated binders such as polytetrafluoroethylene can hinder the uniform dispersion of the particles.

[0172] Example 4: Effect of heat treatment of electrode sheet

[0173] Graphite (BTR-918): Ketjen black (EC 600JD): Polyacrylic acid (LA133) (non-fibrillated binder): Polytetrafluoroethylene (MSK-F104) (fibrillated binder) were mixed at a mass ratio of 80:10:5:5 and uniformly dispersed by an air jet mill (process gas: compressed air, air pressure: 0.3 MPa, room temperature, same below) for 1 h, and the obtained mixture was in a flocculent or muddy state. Then, the mixture was roll-extruded (pressure: 100 kgf / cm 2 ) at room temperature until the thickness was 100 μm to prepare an anode sheet 6 and an anode sheet 7, respectively. In addition, the anode sheet 6 was further vacuum-stored at 180°C for 12 h and naturally cooled down; the anode sheet 7 was not treated. The molding of the anode sheet 6 and the anode sheet 7 (to obtain an anode 6 and an anode 7), and the subsequent magnetron sputtering and half-cell assembly were the same as in Example 2.

[0174] Figure 5 The heat flow curve of the anode sheet 6 prepared in Example 4 was shown. In the Figure 5 , the heat flow of the anode sheet 6 first decreased with the increase of temperature, reached the minimum at about 165°C, then rapidly increased and tended to be stable. It indicated that the non-fibrillated binder underwent phase transition, and the initial powder state melted. After cooling down, it re-solidified and bonded the electrode material particles together.

[0175] Figure 6 The constant current first charge-discharge curves of the CR2032 button half-cells assembled by the anode 6 and the anode 7 prepared in Example 4, respectively, were shown. In the case of heat treatment of the anode sheet before magnetron sputtering, the electrode side reaction was significantly reduced.

[0176] Figure 7 The comparison of the first coulombic efficiency of the CR2032 button half-cells assembled by the anode 6 and the anode 7 prepared in Example 4, respectively, was shown. Compared with the anode 7, the anode 6 improved the first coulombic efficiency from about 70% to about 83%.

[0177] Example 5: Interfacial adhesion and impedance

[0178] Lithium manganese iron phosphate (LiFeMnPO4), carbon nanotube (CNT-3213), sodium alginate (Kelton), and polytetrafluoroethylene (Chemours 601X) were mixed at a mass ratio of 86:4:7:3, and dispersed by an air jet mill (same above) for 60 min, and the obtained mixture was in a flocculent or muddy state. Then, the mixture was roll-pressed (1 x 10 3 kgf / cm 2 ) at 150°C to a thickness of 150 μm to prepare a positive electrode sheet.

[0179] The obtained positive electrode film was laminated with commercial carbon-coated aluminum foil (MTI, 15μm aluminum + 1μm carbon coating) by hot pressing (180℃, 200kg) to obtain positive electrode 26; the obtained positive electrode film was then deposited with an ultrathin aluminum current collector (current collector thickness 1.5μm) by magnetron sputtering to obtain positive electrode 27. The magnetron sputtering conditions were: substrate temperature 25℃, substrate rotation speed 20rpm, target-substrate distance 85mm, and main cavity vacuum degree 3×10 -5 The sputtering conditions were: Pa, argon gas pressure 1.2 Pa, sputtering power 70 W, sputtering time 50 min. The substrate temperature of cathode 28 during magnetron sputtering current collector process was 150 °C, and other conditions were the same as those of cathode 27.

[0180] Then the peel force between the positive electrode membrane and the corresponding current collector in positive electrode 26-28 was tested, and the results are summarized in Table 2.

[0181] Table 2. Results of peel force test for positive electrode current collector

[0182] Number Peel force peak / N Peel force average / N Positive electrode 26 14.45 6.52 Positive electrode 27 18.95 12.47 Positive electrode 28 37.25 19.68

[0183] As shown in Table 2, compared to the positive electrode 26 prepared by combining a positive electrode film with commercially available carbon-coated aluminum foil, the peel force between the positive electrode film and the current collector is greater in both peak and average peel force in the positive electrode prepared by physical deposition, such as magnetron sputtering. Furthermore, the peel force of the positive electrode 28, with a substrate temperature of 150°C during sputtering, is greater than that of the positive electrode 27, with a substrate temperature of 25°C.

[0184] The prepared electrodes were assembled into CR2032 button half-cells as described in Example 6, and then impedance tests were performed.

[0185] Figure 8 To display the electrochemical impedance (ohm) spectra of the cathodes 26, 27, and 28 prepared according to Example 5. From Figure 8 As can be seen, compared with the positive electrode 26 made by combining the positive electrode film with commercial carbon-coated aluminum foil, the positive electrodes 27 and 28, which are deposited by physical deposition such as magnetron sputtering, have lower impedance, especially the impedance of the positive electrode 28 is lower than that of the positive electrode 27.

[0186] Example 6: Specific capacity and capacity surplus ratio

[0187] The preparation process of the dry electrode is as follows:

[0188] The components were mixed in a mass ratio of graphite (MS-QCG-X) : Ketjen black (EC-300J) : sodium carboxymethyl cellulose (DAICEL CMC2200) : polytetrafluoroethylene (MSK-F104) = 80:10:6:4, and dispersed for 4 h at 5000 rpm using a high-speed shearing machine. The resulting mixture was flocculated or muddy. The mixture was then roll-pressed (800 kgf / cm 2 ) at 180°C to a thickness of 70 μm, and then vacuum stored at 180°C for 16 h and naturally cooled to room temperature, to obtain a negative electrode sheet.

[0189] The obtained negative electrode sheet was hot-press laminated (180°C, 200 kgf / cm 2 ) with a commercial carbon-coated copper foil (MTI, 12 μm copper + 1 μm carbon coating) to obtain a negative electrode 11; a 1 μm thick copper and aluminum current collector was deposited on the obtained negative electrode sheet by magnetron sputtering to obtain a negative electrode 12. The magnetron sputtering conditions were: substrate temperature 150°C, substrate rotation speed 5 rpm, target-substrate distance 145 mm, main chamber vacuum degree 8 x 10 -6 Pa, argon gas pressure 0.5 Pa, sputtering power 150 W, and sputtering time 75 min.

[0190] The components were mixed in a mass ratio of NCM523 (T52S) : Ketjen black (EC-300J) : sodium carboxymethyl cellulose (DAICEL CMC2200) : polytetrafluoroethylene (MSK-F104) = 80:10:6:4, and dispersed for 4 h at 5000 rpm using a high-speed shearing machine. The resulting mixture was flocculated or muddy. The mixture was then roll-pressed (600 kgf / cm 2 ) at 180°C to a thickness of 100 μm, and then vacuum stored at 180°C for 16 h and naturally cooled to room temperature, to obtain a positive electrode sheet.

[0191] The obtained positive electrode sheet was hot-press laminated (180°C, 200 kgf / cm 2 ) with a commercial carbon-coated aluminum foil (MTI, 20 μm aluminum + 1 μm carbon coating) to obtain a positive electrode 29; a 1 μm thick aluminum current collector was deposited on the obtained positive electrode sheet by magnetron sputtering to obtain a positive electrode 30. The magnetron sputtering conditions were: substrate temperature 150°C, substrate rotation speed 5 rpm, target-substrate distance 145 mm, main chamber vacuum degree 8 x 10 - 6 Pa, argon gas pressure 0.5 Pa, sputtering power 150 W, and sputtering time 75 min.

[0192] The process for preparing a wet electrode was as follows:

[0193] The wet negative electrode was prepared as follows: the materials were dispersed in NMP in a mass ratio of graphite (MS-QCG-X): Ketjen black (EC-300J): polyvinylidene fluoride (SHV900) = 80:10:10 (the same binder ratio as in negative electrodes 11 and 12), with a solid content of 50%, and a uniform, flowable slurry was formed by ball milling at 300 rpm for 30 min using a ball mill, and the slurry was uniformly coated on a copper foil using a doctor blade, and a wet negative electrode (i.e., wet graphite @ commercial copper) was obtained after vacuum drying.

[0194] The wet positive electrode was prepared as follows: the materials were dispersed in NMP in a mass ratio of NCM523 (T52S): Ketjen black (EC-300J): polyvinylidene fluoride (SHV900) = 80:10:10 (the same binder ratio as in positive electrodes 29 and 30), with a solid content of 40%, and a uniform, flowable slurry was formed by ball milling at 500 rpm for 40 min using a ball mill, and the slurry was uniformly coated on an aluminum foil using a doctor blade, and a wet positive electrode (i.e., wet NCM523 @ commercial aluminum) was obtained after vacuum drying.

[0195] The dry and wet negative electrodes prepared above were assembled into negative electrode CR2032 button half-cells in the manner described in Example 2.

[0196] Positive electrode CR2032 button half-cells were manufactured in a similar manner to the negative electrode CR2032 button half-cells, except that the dry and wet positive electrodes prepared above were used instead of the dry and wet negative electrodes prepared above as the working electrode, and lithium metal was used as the counter electrode.

[0197] The discharge specific capacity of the electrode active material and the discharge specific capacity of the electrode as a whole were measured for the half-cells corresponding to negative electrodes 11-12 and positive electrodes 29-30, respectively. Figure 9 The test results of the discharge specific capacity of the negative electrode half-cells corresponding to negative electrodes 11-12 are presented in Table 1, Figure 10 The test results of the discharge specific capacity of the positive electrode half-cells corresponding to positive electrodes 29-30 at different rates are presented in Table 2.

[0198] As can be seen from Table 1 and Table 2, Figures 9-10 under the same conditions, the electrode active material and the electrode as a whole have higher discharge specific capacity (including the first discharge specific capacity and the cyclic discharge specific capacity) in the electrode prepared by the method of the present application than in the electrode prepared by hot pressing of the dry electrode film and the commercial current collector. This is beneficial to improving the energy density of the energy storage device and improving the cycle performance of the energy storage device.

[0199] In addition, the inventors also studied the cyclic discharge specific capacity of the electrode at different rates. See Figure 10Even if the charge and discharge rate is changed, the electrode prepared by the method of the present application still has higher cycle discharge specific capacity of the electrode active material and the overall electrode than the electrode prepared by hot-pressing lamination of the dry electrode film and the commercial current collector, which shows that the energy storage device such as the secondary battery prepared by the preparation method of the present application also has improved rate performance.

[0200] Further, the inventors also replaced the positive electrode active material with lithium iron phosphate, lithium cobaltate, NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O2) prepared by different methods, respectively, and replaced the negative electrode active material with silicon-carbon material prepared by different methods, respectively, and prepared the positive electrode or the negative electrode in the same way (except that the active materials were different, other conditions were the same). Then, the active material discharge specific capacity of the prepared positive electrode and negative electrode, the electrode positive discharge specific capacity and the capacity remaining ratio were measured, and the test results are summarized in Table 3.

[0201] Table 3: Specific capacity and capacity remaining ratio of different electrodes after 100 cycles

[0202]

[0203]

[0204] *: "dry method" refers to the preparation of an electrode from electrode active material, conductive additive, non-fibrillated binder and fibrillated binder by the method of the present application;

[0205] **: "wet method" refers to the preparation of an electrode by uniformly dispersing electrode active material, conductive additive and binder in a solvent to form a slurry with certain fluidity, and then coating the electrode slurry on a metal foil current collector and drying;

[0206] ***: The active material specific capacity and the overall electrode specific capacity in Table 3 are the results measured at 0.5C rate.

[0207] As can be seen from Table 3, when different electrode active materials are used for testing, compared with the wet electrode film and the electrode prepared by hot-pressing lamination of the dry electrode film and the commercial current collector, the electrode prepared by the dry electrode film of the present application and the magnetron sputtering current collector has higher overall cycle discharge specific capacity of the electrode, and the specific capacity of the active material is also significantly improved.

[0208] In addition, the secondary battery including the electrode prepared by the method of the present application has a higher capacity remaining ratio after 100 cycles, which shows that the life characteristics of the secondary battery are improved.

[0209] Example 7: Cycle discharge specific capacity and energy density of secondary battery

[0210] The negative electrode 14 and the positive electrode 32 were prepared in the same manner as the negative electrode 11 and the positive electrode 29 (both of which employed commercial carbon-coated current collectors) in Example 6, and the negative electrode 15 and the positive electrode 33 were prepared in the same manner as the negative electrode 12 and the positive electrode 30 (both of which were magnetron sputter-deposited current collectors) in Example 6. The negative electrode 14 and the positive electrode 32, and the negative electrode 15 and the positive electrode 33 were then assembled into secondary batteries with a negative electrode capacity to positive electrode capacity ratio (N / P ratio) = 1.15, respectively. The separators and electrolytes employed in the secondary batteries were the same as in Example 2.

[0211] Figure 11 Figures showing the discharge specific capacity of the entire secondary battery as a function of cycle number for secondary batteries employing commercial current collectors and secondary batteries employing magnetron sputter-deposited current collectors are presented. As can be seen from Figure 11 , the secondary batteries employing magnetron sputter-deposited current collectors exhibit higher cycle discharge specific capacities. This indicates that energy storage devices such as secondary batteries prepared using the method of the present application exhibit improved cycle performance.

[0212] Figure 12 Figures showing the charge and discharge voltage versus the discharge specific capacity of the entire secondary battery for the first charge and discharge cycle for secondary batteries employing commercial current collectors and secondary batteries employing magnetron sputter-deposited current collectors are presented. As can be seen from Figure 12 , the secondary batteries employing magnetron sputter-deposited current collectors can provide higher discharge specific capacities at the same electrochemical window.

[0213] The inventors further varied the type of electrode active material, prepared additional secondary batteries under the same conditions, and tested the energy densities of these secondary batteries. The results of the energy density tests are summarized in Table 4.

[0214] Table 4 Energy density test results

[0215]

[0216] As can be seen from Table 4, the secondary batteries employing magnetron sputter-deposited current collectors exhibit higher energy densities than the secondary batteries employing commercial current collectors.

[0217] Example 8: Supercapacitors

[0218] Activated carbon: Ketjen black: polyvinylidene fluoride: polytetrafluoroethylene were mixed in a mass ratio of 90:5:1:4, and dispersed using an air jet mill for 0.5 h to mix uniformly, and the resulting mixture was flocculated or mud-like, and then roll-pressed (pressure 500 kgf / cm 2 , 160°C) to a thickness of 100 μm to obtain an electrode film.

[0219] Two of the prepared electrode films were hot-pressed (temperature 180°C, pressure 200 kgf / cm 2 ) with commercial carbon-coated 20 μm aluminum foil as positive and negative electrodes (combination 1, i.e. activated carbon | commercial aluminum foil).

[0220] In addition, two of the prepared electrode films were each coated with 1 μm of aluminum current collector by magnetron sputtering, under the following magnetron sputtering conditions: substrate temperature 100°C, substrate rotation speed 5 rpm, target-substrate distance 65 mm, main chamber vacuum 8 x 10 -4 Pa, argon gas pressure 0.5 Pa, sputtering power 150 W, sputtering time 15 min. The obtained electrodes were used as positive and negative electrodes (combination 2, i.e. activated carbon | magnetron aluminum).

[0221] The above-prepared positive and negative electrodes of combinations 1 and 2 (i.e. activated carbon | commercial aluminum foil and activated carbon | magnetron aluminum) were assembled into capacitors, which were structure-symmetrical capacitors. The electrolyte used was 6 M KOH aqueous solution.

[0222] Some parameters of the activated carbon electrodes are summarized in Table 5.

[0223] Table 5. Parameters of activated carbon electrodes (under the same active material loading)

[0224]

[0225] Table 6. Performance of activated carbon supercapacitors (under the same active material loading)

[0226]

[0227] As can be seen from Tables 5-6, compared with the capacitor prepared by combination 1 (i.e. activated carbon | commercial aluminum foil), the supercapacitor prepared by the method of the present application has a significantly higher proportion of active material, and the electrode active material also unexpectedly has a higher specific capacitance, so that the supercapacitor prepared by the method of the present application has a significantly higher overall specific capacitance and energy density.

[0228] Example 9: Sodium-ion secondary battery

[0229] Hard carbon: conductive carbon black: sodium carboxymethyl cellulose: polytetrafluoroethylene were mixed in a mass ratio of 90:4:3:3, and the obtained mixture was dispersed by an air jet mill for 0.5 h, and the obtained mixture was in the form of flocs or mud. Then the floc or mud product was roll-pressed (pressure 800 kgf / cm 2 ) at 180°C to a thickness of 100 μm to obtain a negative electrode film.

[0230] Prussian blue (Na2FeFe(CN)6(NaHCF)) : conductive carbon black : sodium carboxymethylcellulose : polytetrafluoroethylene were mixed in a mass ratio of 90 : 4 : 3 : 3, and then dispersed for 0.5 h using an air jet mill (under the same conditions as before). The resulting mixture was in the form of a flocculent or muddy mass. The flocculent or muddy mass was then roll-pressed at 180°C (pressure 600 kgf / cm 2 ) to a thickness of 100 μm, to obtain a positive electrode film.

[0231] The negative electrode film and the positive electrode film were stored in a vacuum at 150°C for 24 h, and then naturally cooled to room temperature.

[0232] The resulting positive electrode film and negative electrode film were each hot-pressed to be laminated with a commercial carbon-coated 20 μm aluminum foil, to obtain a commercial aluminum foil positive electrode and a commercial aluminum foil negative electrode. The resulting positive electrode film and negative electrode film were each provided with a 1 μm aluminum current collector by magnetron sputtering, under the following conditions: substrate temperature 150°C, substrate rotation speed 5 rpm, target-to-substrate distance 80 mm, main chamber vacuum 8 x 10 -6 Pa, argon gas pressure 0.5 Pa, sputtering power 80 W, sputtering time 20 min, to obtain a magnetron sputtered positive electrode and a magnetron sputtered negative electrode.

[0233] Separator: Celgard 2325, thickness 30 μm;

[0234] Electrolyte: 1 M NaPF6solution in DME (100 vol.%).

[0235] The resulting positive and negative electrodes were assembled with a separator and an electrolyte into a sodium-ion secondary battery (N / P ratio = 1.15).

[0236] Table 7. Summary of partial parameters of sodium-ion secondary batteries (under the same active material load)

[0237]

[0238] Table 8. Comparison of performance of sodium-ion batteries

[0239]

[0240] As can be seen from Tables 7-8, compared with a sodium-ion secondary battery prepared by compounding with a commercial aluminum foil, a sodium-ion secondary battery prepared by the method of the present application is more compact and lightweight, and the electrode active material unexpectedly has a higher specific capacity, so that the sodium-ion secondary battery prepared by the method of the present application has a significantly higher energy density.

[0241] Example 10: Deposition of current collector by evaporation

[0242] NCM523: Ketjenblack: sodium carboxymethyl cellulose: polytetrafluoroethylene were dispersed by a high-speed shearing machine at 5000 rpm for 4 h at a mass ratio of 80:10:6:4, and the obtained mixture was in a flocculent or muddy state. Then the flocculent or muddy product was rolled at 180 °C to a thickness of 100 μm to obtain a positive electrode film. The obtained positive electrode film was stored in vacuum at 180 °C for 16 h and naturally cooled to room temperature. Then an aluminum layer with a thickness of 1 μm was deposited on the surface of the cooled positive electrode film by vacuum evaporation, and the evaporation conditions were as follows: evaporation temperature 680 °C, vacuum degree 10 -2 Pa, evaporation time 15 min.

[0243] The above description is only exemplary embodiments of the present application. It should be noted that for those skilled in the art, improvements can be made to the present application without departing from the inventive concept, but these all belong to the protection scope of the present application.

Claims

1. A method for preparing an electrode, comprising: (1) preparing an electrode sheet, comprising: (a) mixing mixing an electrode active material, a conductive additive, a non-fibrillar binder uniformly, and then adding a fibrillar binder, and processing the resulting mixture into a flocculent or muddy form; (b) shaping shaping the flocculent or muddy product from step (a) into an electrode sheet, wherein there is no pre-shaping step prior to step (b); (2) depositing a current collector, comprising: depositing a metal layer as a current collector on one surface of the electrode sheet from step (1) by a physical deposition method; wherein step (1) further comprises, after the electrode sheet is prepared, heat treating the resulting electrode sheet by keeping it at a temperature of 100-250 °C in vacuum for 4-20 h; wherein the method for preparing an electrode does not use a solvent.

2. The method for preparing an electrode according to claim 1, wherein the heat treating is performed by keeping the resulting electrode sheet at a temperature of 150-200 °C in vacuum for 8-16 h.

3. The method for preparing an electrode according to claim 1, wherein the physical deposition method is selected from one or more of sputter plating, evaporation plating, or ion plating.

4. The method for preparing an electrode according to claim 1, wherein the physical deposition method is magnetron sputtering.

5. The electrode preparation method according to claim 4, wherein the process conditions of the magnetron sputtering are: substrate temperature of 10-300℃, substrate rotation speed of 0-20 rpm, target-substrate distance of 50-200 mm; main chamber vacuum degree of 5x10 -3 -5x10 -6 Pa, process gas pressure of 0.5-15 Pa, power supply power of 20-500 W, and sputtering time of 20-5000 s.

6. The method for preparing an electrode according to claim 5, wherein the substrate temperature is 20-200 °C.

7. The method for preparing an electrode according to any one of claims 1-6, wherein one or more of the following conditions are met: i. the mixing in step (a) is performed by one or more of ball milling, jet milling, high speed shear, or mechanical milling; ii. the shaping of the flocculent or muddy product from step (a) into an electrode sheet is performed by one of roll shaping, extrusion shaping, injection molding, blow molding, coating molding, or casting; iii. step (2) comprises depositing a patterned metal layer as a current collector on the one surface of the electrode sheet from (1); iv. step (2) comprises, prior to depositing the metal layer, a pre-treatment step for the electrode sheet selected from one or more of plasma cleaning and surface etching.

8. The method for preparing an electrode according to claim 7, wherein the roll shaping is hot roll shaping.

9. The method for preparing an electrode according to claim 7, wherein the shaping of the flocculent or muddy product from step (a) into an electrode sheet is performed by one of roll shaping, extrusion shaping.

10. The electrode production method according to claim 7, wherein the roll forming conditions are a roll temperature of 10 to 200°C, a roll pressure of 0.1 x 10 3 -20.0 x 10 3 kgf / cm 2 , a roll speed of 0.5 to 50 m / min, and a number of rollings of 1 to 30. 1 11. The method for preparing an electrode according to claim 7, wherein the process gas for the plasma cleaning is selected from one or more of oxygen, helium, argon, or xenon.

12. The method for preparing an electrode according to claim 7, wherein the time for the surface etching is 1-10 min.

13. The method for preparing an electrode according to any one of claims 1-6, wherein one or more of the following conditions are met: vi. the non-fibrillar binder is selected from one or more of polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, sodium alginate, poly(ethylene oxide), polyacrylonitrile (PAN), polyimide (PI), cellulose, and cellulose derivatives; vii. the fibrillated binder is selected from polytetrafluoroethylene; viii. a weight ratio of an added amount of the fibrillated binder to an added amount of the non-fibrillated binder is 0.1:1 to 10:1, based on a dry weight of the electrode sheet; ix. the added amount of the fibrillated binder is 0.5-10% by weight, based on the dry weight of the electrode sheet; x. the added amount of the non-fibrillated binder is 0.5-10% by weight, based on the dry weight of the electrode sheet; or xi. a total added amount of the non-fibrillated binder and the fibrillated binder is 1-15% by weight, based on the dry weight of the electrode sheet.

14. The electrode production method according to claim 13, wherein the cellulose derivative is selected from the group consisting of cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, nitrocellulose, carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose, sodium carboxymethyl cellulose, and sodium nitrocellulose.

15. The electrode production method according to claim 13, wherein the non-fibrillated binder is selected from one or more of polyvinylidene fluoride, sodium carboxymethyl cellulose, polyacrylic acid, and sodium alginate.

16. The electrode production method according to claim 13, wherein a weight ratio of an added amount of the fibrillated binder to an added amount of the non-fibrillated binder is 0.1:1 to 3.0:1, based on a dry weight of the electrode sheet.

17. The electrode production method according to claim 13, wherein the added amount of the fibrillated binder is 1-5% by weight, based on the dry weight of the electrode sheet.

18. The electrode production method according to claim 13, wherein the added amount of the non-fibrillated binder is 1-8% by weight, based on the dry weight of the electrode sheet.

19. The electrode production method according to claim 13, wherein a total added amount of the non-fibrillated binder and the fibrillated binder is 1-10% by weight, based on the dry weight of the electrode sheet.

20. The electrode production method according to any one of claims 1-6, wherein the electrically conductive additive is selected from one or more of graphite, carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

21. The electrode production method according to any one of claims 1-6, wherein the electrically conductive additive is selected from one or more of super-P, acetylene black, and ketjen black.

22. The electrode production method according to any one of claims 1 to 6, wherein The amount of the electrically conductive additive is 0.5-10% by weight, based on a dry weight of the electrode sheet.

23. The electrode production method according to any one of claims 1-6, wherein one or more of the following conditions is satisfied: xii. a ratio of a thickness of the current collector to a thickness of the electrode sheet is in a range of 0.0001:1 to 0.1000:1; xiii. the thickness of the current collector is 0.1-10 μm; or xiv. the thickness of the electrode sheet is 10-1000 μm.

24. The electrode production method according to claim 23, wherein a ratio of a thickness of the current collector to a thickness of the electrode sheet is in a range of 0.0050: 1 to 0.0300:

1.

25. The electrode production method according to claim 23, wherein the thickness of the current collector is 0.5-2 μm.

26. The electrode production method according to claim 23, wherein the thickness of the electrode sheet is 50-200 μm.

27. An electrode produced according to the electrode production method of any one of claims 1-26.

28. An energy storage device comprising a positive electrode and a negative electrode, wherein at least one of the positive electrode and the negative electrode comprises the electrode according to claim 27.

29. The energy storage device according to claim 28, wherein the positive electrode and the negative electrode comprise the electrode according to claim 27.

30. The energy storage device according to claim 28, wherein the energy storage device is a lithium-ion secondary battery, a sodium-ion secondary battery, a lithium-sulfur secondary battery, or a capacitor.

31. The energy storage device according to claim 30, wherein the capacitor is a supercapacitor.

32. The energy storage device according to claim 30, wherein the capacitor is a lithium-ion capacitor.

33. The energy storage device according to claim 28, wherein the energy storage device is a lithium-ion secondary battery or a sodium-ion secondary battery.

34. The energy storage device according to claim 30, wherein when the energy storage device is a lithium-ion secondary battery, a positive electrode active material is selected from one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-containing phosphate of olivine structure.

35. The energy storage device of claim 30, wherein when the energy storage device is a lithium-ion secondary battery, the positive active material is selected from one or more of LiFeMnPO4, LiCoO2, LiMn2O4, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.5 Co 0.3 Mn 0.2 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, and LiFePO4.

36. The energy storage device according to any one of claims 34-35, wherein in the lithium-ion secondary battery, an amount of the positive electrode active material is 80-98% by weight based on a dry weight of the positive electrode sheet.

37. The energy storage device according to any one of claims 34-35, wherein in the lithium-ion secondary battery, an amount of the positive electrode active material is 90-98% by weight based on a dry weight of the positive electrode sheet.

38. The energy storage device according to claim 30, wherein when the energy storage device is a lithium-ion secondary battery, a negative electrode active material is selected from one or more of natural graphite, artificial graphite, hard carbon, soft carbon, silicon-based material, tin-based material, lithium titanate, and metallic lithium.

39. The energy storage device according to claim 30, wherein when the energy storage device is a lithium-ion secondary battery, a negative electrode active material is mesocarbon microbead.

40. The energy storage device according to claim 30, wherein when the energy storage device is a lithium-ion secondary battery, a negative electrode active material is selected from one or more of graphite and silicon-based material.

41. The energy storage device according to claim 30, wherein when the energy storage device is a lithium-ion secondary battery, a negative electrode active material is selected from one or more of graphite, silicon-carbon composite, and silicon alloy.

42. The energy storage device of any one of claims 38-41, wherein the amount of the negative electrode active material is 80-98 wt% based on the dry weight of the negative electrode film in a lithium-ion secondary battery.

43. The energy storage device of any one of claims 38-41, wherein the amount of the negative electrode active material is 90-98 wt% based on the dry weight of the negative electrode film in a lithium-ion secondary battery.

44. The energy storage device of claim 30, wherein the positive electrode active material is selected from one or more of layered transition metal oxides or Prussian blue analogues when the energy storage device is a sodium-ion secondary battery.

45. The energy storage device of claim 30, wherein when the energy storage device is a sodium-ion secondary battery, the positive active material is selected from Na2FeFe(CN)6 (NaHCF), NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2, Na2FeP2O7, Na4Fe3(PO4)2(P2O7), Na3V2(PO4)3, NaFePO4, and NaMnFe(CN)6.

46. The energy storage device of any one of claims 44-45, wherein the amount of the positive electrode active material is 80-98 wt% based on the dry weight of the positive electrode film in a sodium-ion secondary battery.

47. The energy storage device of any one of claims 44-45, wherein the amount of the positive electrode active material is 90-98 wt% based on the dry weight of the positive electrode film in a sodium-ion secondary battery.

48. The energy storage device of claim 30, wherein the negative electrode active material is selected from one or more of natural graphite, artificial graphite, hard carbon, soft carbon, silicon-based materials, and tin-based materials when the energy storage device is a sodium-ion secondary battery.

49. The energy storage device of claim 30, wherein the negative electrode active material is mesocarbon microbeads when the energy storage device is a sodium-ion secondary battery.

50. The energy storage device of claim 30, wherein the negative electrode active material is selected from one or more of graphite and silicon-based materials when the energy storage device is a sodium-ion secondary battery.

51. The energy storage device of claim 30, wherein the negative electrode active material is selected from one or more of graphite, silicon-carbon composites, and silicon alloys when the energy storage device is a sodium-ion secondary battery.

52. The energy storage device of any one of claims 48-51, wherein the amount of the negative electrode active material is 80-98 wt% based on the dry weight of the negative electrode film in a sodium-ion secondary battery.

53. The energy storage device of any one of claims 48-51, wherein the amount of the negative electrode active material is 90-98 wt% based on the dry weight of the negative electrode film in a sodium-ion secondary battery.

54. The energy storage device of claim 30, wherein the positive electrode active material is selected from one or more of lithium sulfide, titanium sulfide, phosphorus sulfide, or organic compounds having linear alkyl, branched alkyl, naphthenic, aromatic hydrocarbons, heteroatom-containing aromatic hydrocarbons combined with sulfur when the energy storage device is a lithium-sulfur secondary battery.

55. The energy storage device of claim 30, wherein the positive electrode active material is selected from one or more of sulfur-carbon composite positive electrode materials and sulfidized polyacrylonitrile when the energy storage device is a lithium-sulfur secondary battery.

56. The energy storage device of any one of claims 54-55, wherein the amount of the positive electrode active material is 80-98 wt% based on the dry weight of the positive electrode film in a lithium-sulfur secondary battery.

57. The energy storage device of any one of claims 54-55, wherein the amount of the cathode active material is 90-98 wt% based on the dry weight of the cathode sheet in a lithium-sulfur secondary battery.

58. The energy storage device of claim 30, wherein the anode active material is selected from metallic lithium when the energy storage device is a lithium-sulfur secondary battery.

59. The energy storage device of claim 58, wherein the amount of the anode active material is 80-99 wt% based on the dry weight of the anode sheet in a lithium-sulfur secondary battery.

60. The energy storage device of claim 58, wherein the amount of the anode active material is 90-99 wt% based on the dry weight of the anode sheet in a lithium-sulfur secondary battery.

61. The energy storage device of claim 30, wherein the cathode active material is selected from one or more of a metal oxide, a conductive polymer, and a carbon material when the energy storage device is a capacitor.

62. The energy storage device of claim 30, wherein the cathode active material is selected from one or more of Mn02, NiO, Co304, polyaniline, polypyrrole, activated carbon, graphene, and biochar when the energy storage device is a capacitor.

63. The energy storage device of any one of claims 61-62, wherein the amount of the cathode active material is 80-98 wt% based on the dry weight of the cathode sheet in a capacitor.

64. The energy storage device of any one of claims 61-62, wherein the amount of the cathode active material is 90-98 wt% based on the dry weight of the cathode sheet in a capacitor.

65. The energy storage device of claim 30, wherein the anode active material is selected from one or more of a metal, a carbon material, a conductive polymer, a metal oxide, a metal-organic framework-derived material when the energy storage device is a capacitor.

66. The energy storage device of claim 30, wherein the anode active material is selected from one or more of aluminum, zinc, activated carbon, graphite, polyaniline, polypyrrole, polythiophene, and Mn02 when the energy storage device is a capacitor.

67. The energy storage device of any one of claims 65-66, wherein the amount of the anode active material is 80-98 wt% based on the dry weight of the anode sheet in a capacitor.

68. The energy storage device of any one of claims 65-66, wherein the amount of the anode active material is 90-98 wt% based on the dry weight of the anode sheet in a capacitor.

Images