Electrode preparation method, electrode prepared by electrode preparation method, energy storage device comprising electrode and electrode production system

Abstract

The invention relates to an electrode preparation method, an electrode prepared by the method, an energy storage device comprising the electrode and an electrode production system for carrying out the method. The preparation method comprises the following steps: (a) providing a self-supporting electrode film which comprises a first side and a second side opposite to the first side, and the second side comprises a to-be-deposited area on which metal is deposited when the self-supporting electrode film is in contact with an electrolyte for an electrodeposition reaction; (b) providing an electrolyte containing a salt of a metal to be deposited; and (c) contacting at least the region to be deposited of the second side of the self-supporting electrode film with the electrolyte, and performing an electrodeposition reaction in the region to be deposited, thereby depositing a current collector of the metal to be deposited on the second side, where the electrodeposition temperature is 0 to 70 DEG C. According to the electrode prepared by the method disclosed by the invention, the active substance in the electrode has excellent first discharge specific capacity, first coulombic efficiency and cycle performance.

Description

Technical Field

[0001] The present invention generally relates to the technical field of electrochemical energy storage. Specifically, the present invention relates to a method for preparing an electrode, an electrode obtained by the method, an energy storage device including the electrode, and an electrode production system for performing the method for preparing the electrode. Background Art

[0002] Electrochemical energy storage devices have a wide range of applications in fields such as consumer electronics, electric vehicles, and energy storage power grids. The electrode provides a place for charge storage / release and is an important component in electrochemical devices. Traditional methods for preparing electrodes are to coat or spray electrode slurries on current collectors, or to bond self-supporting electrode membranes to current collectors by hot pressing. As people's requirements for the performance of electrochemical energy storage devices, such as initial discharge specific capacity, initial Coulombic efficiency, and cycling performance, are getting higher and higher, new methods for preparing electrodes are needed to better meet the growing needs of people. In view of this, there is still a need to develop a new method for preparing electrodes, and the energy storage devices assembled from the electrodes prepared by this method have excellent initial discharge specific capacity, initial Coulombic efficiency, and cycling performance. Summary of the Invention

[0003] The present invention is made in view of the above problems existing in the prior art.

[0004] In a first aspect, the present invention relates to a method for preparing an electrode, comprising:

[0005] (a) providing a self-supporting electrode membrane, which includes a first side and a second side opposite to the first side, and the second side includes a deposition region where a metal is deposited thereon when contacting with an electrolyte to perform an electrodeposition reaction;

[0006] (b) providing an electrolyte containing a salt of the metal to be deposited;

[0007] (c) contacting at least the deposition region of the second side of the self-supporting electrode membrane with the electrolyte, and performing an electrodeposition reaction in the deposition region, so as to deposit a current collector of the metal to be deposited on the second side, wherein the electrodeposition temperature is 0 to 70 °C, preferably 0 to 30 °C, more preferably 0 to 20 °C, and even more preferably 0 to 10 °C.

[0008] The preparation method of the present invention can significantly reduce the volume and mass ratio of auxiliary components (such as sheet current collectors for coating active materials) in the battery by electro-depositing a current collector on a self-supporting electrode membrane, and improve the mass specific capacity and volume specific capacity of the energy storage device. Further, in addition to the increase in specific capacity brought about by the reduction in the mass and volume of the auxiliary components, unexpectedly, compared with the electrodes prepared by coating positive and negative active materials on positive and negative current collectors, the electrodes prepared by the preparation method of the present invention have a higher first discharge specific capacity, a higher first Coulombic efficiency, and more excellent cycling performance.

[0009] The inventors unexpectedly found that when preparing an electrode by electro-depositing on an electrode membrane, controlling the electro-deposition temperature (i.e., the electrolyte temperature) within a specific range, especially within a relatively low temperature range, can improve the first discharge specific capacity, the first Coulombic efficiency, and the cycling performance of the active substances contained in the electrode.

[0010] In addition, the inventors also unexpectedly found that during electro-deposition, by providing an auxiliary conductor in contact with the self-supporting electrode membrane on a part or all of the corresponding area on the first side of the self-supporting electrode membrane that is opposite to the deposition area on the second side, not only can the electro-deposition efficiency be significantly improved and the uniformity of the deposited current collector layer be improved, but also the first discharge specific capacity and the cycling performance of the electrode thus prepared can be significantly improved.

[0011] In addition, the inventors also found that by regulating the surface roughness of the self-supporting electrode membrane, etc., the first discharge specific capacity, the first Coulombic efficiency, and the cycling performance of the active substances contained therein can be further improved.

[0012] In a second aspect, the present invention relates to an electrode prepared by the method described in the first aspect of the present invention.

[0013] In a third aspect, the present invention relates to an energy storage device comprising the electrode described in the second aspect of the present invention.

[0014] In a fourth aspect, the present invention relates to an electrode production system, comprising:

[0015] A self-supporting electrode membrane providing module for providing a self-supporting electrode membrane, the self-supporting electrode membrane comprising a first side and a second side opposite to the first side, the second side comprising a deposition area where metal is deposited thereon when in contact with an electrolyte for an electro-deposition reaction;

[0016] An optional surface cleaning and treatment module, located upstream of the electro-deposition module, for cleaning and treating the surface of the self-supporting electrode membrane;

[0017] An electrolyte providing module for providing an electrolyte for electro-deposition to the electro-deposition module;

[0018] A temperature control module for controlling the temperature of the electrodeposition module to control the electrodeposition temperature at 0 to 70 °C, preferably 0 to 30 °C, more preferably 0 to 20 °C, and even more preferably 0 to 10 °C;

[0019] An electrodeposition module, located downstream of the self-supporting electrode film providing module and the electrolyte providing module, for depositing a current collector on the second side of the self-supporting electrode film;

[0020] An optional cleaning and drying module, located downstream of the electrodeposition module, for cleaning and drying the prepared electrode;

[0021] A transmission module for moving the self-supporting electrode film between the various modules of the electrode production system; and

[0022] An optional collection and transportation module for collecting and transporting the prepared electrodes.

[0023] The electrode production system of the present invention has the advantages of simple process, high production efficiency, low energy consumption, no pollution, and can be conveniently combined with the commonly used production equipment in the prior art, etc., which is conducive to realizing continuous and large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To more clearly illustrate the technical solutions of the present invention, the drawings required for describing the embodiments will be briefly described below. It should be understood that these drawings are only for facilitating those skilled in the art to more easily understand the present invention, rather than intending to limit the scope of the present invention.

[0025] Figure 1 It is a schematic diagram of the electrode preparation method of the present invention.

[0026] Figure 2 It is a schematic diagram of setting an auxiliary conductor and a protective layer on the self-supporting electrode film.

[0027] Figure 3 It shows the first charge-discharge curves at a constant current of button half-cell 1 and button half-cell 2 prepared according to Example 1.

[0028] Figure 4 It respectively shows pictures of the negative electrode 1 ( Figure 4 b) and the negative electrode 2 ( Figure 4 a) after 100 charge-discharge cycles.

[0029] Figure 5 It shows the change of the areal density (mg / cm 2 ) and the thickness with the electrodeposition time during the preparation of the negative electrode 3.

[0030] Figure 6 It shows the electrodeposition coverage effect with the electrodeposition time (Figure 6 a: 60 seconds, Figure 6 b: 120 seconds).

[0031] Figure 7 respectively show the cross-sectional scanning electron microscope images of the negative electrode 2 ( Figure 7 b) and the negative electrode 6 ( Figure 7 a).

[0032] Figure 8 Shows a schematic diagram of testing the internal resistance value of the electrode by the two-probe method.

[0033] Figure 9 Shows the impedance test results of the coin half-cell 1 and the coin half-cell 2.

[0034] Figure 10 Shows the variation of the discharge specific capacity and energy density of the full cell 1 and the full cell 2 with the number of cycles.

[0035] Figure 11 Shows the pictures of the negative electrodes prepared at different electrodeposition temperatures, where from left to right are the negative electrode 9, the negative electrode 10, the negative electrode 11, and the negative electrode 12.

[0036] Figure 12 Is a schematic diagram of an embodiment of the electrode production system of the present invention.

[0037] Figure 13 Is a schematic diagram of another embodiment of the electrode production system of the present invention. Detailed implementation mode

[0038] In order to make the invention purpose, technical solution and beneficial technical effects of this application clearer, the following will describe this application in detail. It should be noted that the various aspects, features, implementation modes, and their advantages described in this application can be compatible and / or combined together.

[0039] Unless otherwise specified, the meaning of the scientific and technical terms in this specification is the same as that generally understood by those skilled in the art.

[0040] In this application, unless otherwise specified, the temperature is room temperature (25 °C), the atmosphere is air, and the pressure is atmospheric pressure.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "middle", etc. is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0042] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0043] The present invention relates to a method for preparing an electrode, an electrode obtained by the method, an energy storage device including the electrode, and an electrode production system for performing the method for preparing the electrode.

[0044] The electrode can be an electrode in an energy storage device, such as a secondary battery, such as a lithium-ion secondary battery, a sodium-ion secondary battery, a capacitor, such as a supercapacitor, such as a positive electrode and / or a negative electrode.

[0045] The present invention will be specifically described below.

[0046] Electrode preparation method

[0047] In a first aspect, the present invention relates to a method for preparing an electrode, comprising:

[0048] (a) providing a self-supporting electrode film, which includes a first side and a second side opposite to the first side, and the second side includes a deposition region where a metal is deposited when contacting with an electrolyte to perform an electrodeposition reaction;

[0049] (b) providing an electrolyte containing a salt of the metal to be deposited;

[0050] (c) contacting at least the deposition region of the second side of the self-supporting electrode film with the electrolyte, and performing an electrodeposition reaction in the deposition region, so as to deposit a current collector of the metal to be deposited on the second side, wherein the electrodeposition temperature is 0 to 70 °C, preferably 0 to 30 °C, more preferably 0 to 20 °C, and even more preferably 0 to 10 °C.

[0051] By electrodepositing a current collector on the self-supporting electrode film, the preparation method of the present invention can significantly reduce the volume and mass ratio of auxiliary components (such as a sheet current collector for coating an active material) in the battery, and improve the mass specific capacity and volume specific capacity of the energy storage device. Further, in addition to the increase in specific capacity brought about by the reduction in the mass and volume of the auxiliary components, unexpectedly, compared with an electrode prepared by coating positive and negative active materials on positive and negative current collectors, the electrode prepared by the preparation method of the present invention has a higher first discharge specific capacity, a higher first Coulombic efficiency, and more excellent cycle performance.

[0052] The inventors unexpectedly found that when preparing an electrode by electrodeposition on an electrode film, controlling the electrodeposition temperature (i.e., the electrolyte temperature) within a specific range, especially within a relatively low temperature range, can improve the first discharge specific capacity, the first Coulombic efficiency, and the cycle performance of the active substances contained in the electrode.

[0053] In addition, the inventors also unexpectedly found that during electrodeposition, by providing an auxiliary conductor in contact with the self-supporting electrode film on a part or all of the corresponding area on the first side of the self-supporting electrode film that is opposite to the deposition area on the second side, not only can the electrodeposition efficiency be significantly improved and the uniformity of the deposited current collector layer be improved, but also the initial discharge specific capacity and cycling performance of the electrode thus prepared can be significantly improved.

[0054] In addition, the inventors also found that by regulating the surface roughness of the self-supporting electrode film, etc., the initial discharge specific capacity, initial Coulombic efficiency, and cycling performance of the active material contained therein can be further improved.

[0055] Figure 1 is a schematic diagram of the electrode preparation method of the present invention. Refer to Figure 1 , the electrode preparation method of the present invention may include: providing a self-supporting electrode film; providing an electrolyte containing a salt of a metal to be deposited; and electrodepositing a current collector on one side of the self-supporting electrode film.

[0056] Next, each step of the electrode preparation method of the present invention will be introduced in detail respectively.

[0057] Step (a)

[0058] Step (a) provides a self-supporting electrode film, which includes a first side and a second side opposite to the first side, and the second side includes a deposition area where a metal is deposited when in contact with an electrolyte for an electrodeposition reaction.

[0059] Those skilled in the art can easily understand that the term "self-supporting" means that the electrode film can be self-standing and has sufficient strength to be rolled up, processed, and unfolded during electrode manufacturing without other supporting elements.

[0060] The present invention has no particular requirements for the self-supporting electrode film used, and self-supporting electrode films commonly used in the art can be adopted.

[0061] In some embodiments, the self-supporting electrode film can be commercially available. In some embodiments, the self-supporting electrode film can be prepared by conventional methods in the art. As an example, the self-supporting electrode film can be obtained by uniformly dispersing an electrode active material, a conductive agent, a binder, an optional thickening agent, etc. in a certain proportion, and then through processes such as rolling and drying.

[0062] The present invention has no particular requirements for the amount of the electrode active material in the self-supporting electrode film, and the amounts commonly used in the art can be adopted. As an example, based on the total dry weight of the self-supporting electrode film, the amount of the electrode active material can be 70-99% by weight, for example, 80-90% by weight.

[0063] The present invention has no particular requirements for the type and amount of the conductive agent in the self-supporting electrode film, and the types and amounts commonly used in the art can be adopted. As an example, the conductive agent 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. In addition, as an example, based on the total dry weight of the self-supporting electrode film, the amount of the conductive agent can be 0.5-15.0 wt%, for example, 2.0-5.0 wt%.

[0064] The present invention has no particular requirements for the type and amount of the binder in the self-supporting electrode film, and the types and amounts commonly used in the art can be adopted. As an example, the binder can be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC-Na), polyacrylic acid, polyvinyl alcohol, sodium alginate, poly(ethylene oxide), polyacrylonitrile, polyimide, cellulose, and cellulose derivatives (such as cellulose acetate, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, nitrocellulose, carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, carboxyisopropyl cellulose), etc. In addition, as an example, based on the total dry weight of the self-supporting electrode film, the amount of the binder can be 0.5-15.0 wt%, for example, 2.0-5.0 wt%.

[0065] The present invention has no particular requirements for the type and amount of the thickener in the self-supporting electrode film, and the types and amounts commonly used in the art can be adopted. As an example, the thickener can be selected from sodium carboxymethyl cellulose, etc. As an example, based on the total dry weight of the self-supporting electrode film, the amount of the thickener can be 0.2-4.0 wt%, for example, 0.2-2.5 wt%.

[0066] Preferably, the surface roughness of at least one surface of the self-supporting electrode film, preferably both surfaces, can be 0.02 - 0.50 μm, such as 0.02 - 0.20 μm. The term "surface roughness" as used herein refers to the unevenness of a processed surface with smaller spacing and minute peaks and valleys, which is the distance between two adjacent wave crests or between two adjacent wave troughs. In some embodiments, the surface roughness of the surface of the self-supporting electrode film on which electrodeposition is performed can be 0.02 - 0.50 μm, such as 0.02 - 0.20 μm. In other embodiments, the surface roughness of both surfaces of the self-supporting electrode film can be 0.02 - 0.50 μm, such as 0.02 - 0.20 μm. As an example, the surface roughness can be 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50 μm, or within the range defined by any two of them. When the surface roughness of the self-supporting electrode film is within the above range, it helps to further improve the initial discharge specific capacity and cycling performance of the energy storage device prepared by the method of the present invention. The surface roughness of the self-supporting electrode film can be adjusted by methods commonly used in the art, such as by changing rolling conditions, plasma bombardment, surface etching and other technical means. The surface roughness can be measured by methods commonly used in the art, such as by interferometry, optical sectioning method, etc.

[0067] In some embodiments, the thickness of the self-supporting electrode film of the present invention can be 10 - 500 μm, such as 20 - 200 μm. As an example, the thickness of the self-supporting electrode film can be 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150, 180, 200, 220, 250, 280, 300, 320, 350, 380, 400, 420, 450, 480, 500 μm, or within the range defined by any two of them.

[0068] In some embodiments, the self-supporting electrode film is a positive electrode film, and the metal to be deposited is aluminum.

[0069] In some embodiments, the self-supporting electrode film is a negative electrode film, and the metal to be deposited is copper.

[0070] In some embodiments, the provided self-supporting electrode film may optionally be surface-cleaned before electroplating. For example, the first side or the second side or both sides of the self-supporting electrode film are washed with a solvent such as deionized water, ethanol, N-methylpyrrolidone or other organic or inorganic solvents to remove impurities and dirt on the surface of the self-supporting electrode film and ensure the surface of the self-supporting electrode film is clean. Alternatively, an air stream may be used to blow the first side or the second side or both sides of the self-supporting electrode film to remove particulate matter or residual solvent on the surface of the self-supporting electrode film. Preferably, for the first side or the second side or both sides of the self-supporting electrode film, it may be washed with a solvent and then blown with an air stream.

[0071] In some embodiments, the provided self-supporting electrode film may also optionally be surface-treated. For example, a pair of counter rollers may be provided to roll the self-supporting electrode film to apply normal stress and shear stress to its surface, thereby reducing the porosity of the self-supporting electrode film and improving the flatness of the electrode surface; and / or the self-supporting electrode film may be charged, for example, by electrostatic corona treatment, etc., to enhance the bonding force between the self-supporting electrode film and the deposited metal layer during electroplating; and / or the surface of the self-supporting electrode film may be treated with a plasma of a gas such as argon or oxygen under normal pressure or vacuum conditions, so as to produce physical and chemical effects on the surface of the self-supporting electrode film, thereby improving the wettability of the surface of the self-supporting electrode film with the electrolyte and enhancing the adhesion.

[0072] In some embodiments, step (a) further includes providing an auxiliary conductor on at least a part or all of a first region on the first side of the self-supporting electrode film, the first region being a corresponding region opposite to the deposition region on the second side, and the auxiliary conductor contacting the first region during electroplating.

[0073] The present invention has no particular requirements for the material of the auxiliary conductor, and a material having a conductive function commonly used by those skilled in the art may be used. For example, the material of the auxiliary conductor may be selected from one or more of copper, aluminum, nickel, iron, gold, silver, platinum, tantalum, etc.

[0074] It should be noted that the term "a part" means that the auxiliary conductor may form a point contact, a line contact or a surface contact with the first region. In the case of forming a point contact, the auxiliary conductor contacts the first region only at a specific point; in other cases, the auxiliary conductor forms a line contact or a surface contact with the first region.

[0075] The expression "the corresponding region opposite to the deposition region to be deposited on the second side" refers to the region opposite to the deposition region to be deposited on the second side of the self-supporting electrode film in the normal direction of the deposition region to be deposited on the second side of the self-supporting electrode film (the thickness direction of the self-supporting electrode film). This can be referred to Figure 2 for understanding. Figure 2 FIG. is a schematic diagram of arranging an auxiliary conductor and a protective layer on a self-supporting electrode film. In Figure 2 , the auxiliary conductor 12 is arranged on the self-supporting electrode film 13, the protective layer 11 is arranged on the auxiliary conductor 12, 15 is the deposition region to be deposited on the second side of the self-supporting electrode film 13, and 14 is the corresponding region opposite to the deposition region 15 on the second side of the self-supporting electrode film 13, that is, the first region. In Figure 2 , the auxiliary conductor exemplarily completely covers the first region.

[0076] In some embodiments, the auxiliary conductor is selected from metal foils such as copper foil or aluminum foil, and step (a) further optionally includes arranging a protective layer on at least the first region on the first side of the self-supporting electrode film, and the protective layer is used to protect the first side from depositing a current collector during the electroplating process. The method further includes removing the auxiliary conductor and the optional protective layer after the electroplating is completed. As an example, the protective layer can completely cover the first side, or when the self-supporting electrode film is only partially immersed in the electrolyte, completely cover the first region but does not need to completely cover the first side of the self-supporting electrode film. As an example, the auxiliary conductor can be arranged between the first side of the self-supporting electrode film and the protective layer.

[0077] The present invention has no special requirements for the material of the protective layer, and the materials commonly used by those skilled in the art can be adopted, as long as the first side of the self-supporting electrode film can be effectively protected from depositing a current collector during the electroplating process. As an example, the protective layer can be made of a material selected from one or more of polyimide (PI), polyethylene (PE), polypropylene (PP), and polytetrafluoroethylene (PTFE).

[0078] In some embodiments, the auxiliary conductor is selected from conductive rollers, and all or at least the surface of the conductive roller is made of a metal such as copper or aluminum. It is easy for those skilled in the art to understand that when the auxiliary conductor is a conductive roller, for example, in a continuous production process, the electrode obtained by electroplating can be separated from the auxiliary conductive roller as the auxiliary conductive roller rotates and the electrode itself moves.

[0079] Step (b)

[0080] Step (b) provides an electrolyte containing a salt of the metal to be deposited.

[0081] The present invention has no particular requirements for the composition of the electrolyte, and an electrolyte commonly used in the art for electroplating can be used, as long as the electrolyte contains a salt of the metal to be deposited so as to be able to effectively deposit the metal to be deposited.

[0082] In some embodiments, the metal to be deposited may be a metal element contained in a current collector commonly used in the art. As an example, the metal to be deposited may be selected from one or more of copper, aluminum, nickel, iron, gold, silver, platinum, tantalum, etc.

[0083] It is readily understood by those skilled in the art that the electrolyte may be an aqueous system or a non-aqueous system, and includes: a solvent; a salt containing the metal to be deposited; and optionally one or more of a leveling agent, a brightening agent, a stabilizer, an acid or a base. The present invention has no particular requirements for the type of the salt containing the metal to be deposited, as long as it can effectively deposit the metal to be deposited during electroplating. As an example, the salt containing the metal to be deposited may be selected from one or more of sulfates of the metal to be deposited such as copper sulfate, zinc sulfate, nickel sulfate, chlorides such as nickel chloride, etc.

[0084] The present invention has no particular requirements for the concentration of the salt containing the metal to be deposited, and a concentration range commonly used in the art can be used. As an example, the concentration of the salt containing the metal to be deposited may be 50 - 500 g / L, for example 50 - 350 g / L.

[0085] In some embodiments, the electrolyte is an aqueous system, and the solvent includes water and optionally further includes an organic solvent miscible with water. For example, the electrolyte may be a mixed aqueous solution of copper sulfate, glucose, and sulfuric acid.

[0086] In some embodiments, the electrolyte is a non-aqueous system, and the electrolyte includes an organic solvent and / or an ionic liquid.

[0087] Preferably, the organic solvent may be selected from one or more of ethers (such as tetrahydrofuran), aromatic hydrocarbons, and their derivatives. For example, the organic solvent may be dimethyl sulfoxide. For example, the electrolyte may be AlBr 3 -MBr-benzene (where M is a metal), such as AlCl 3 -toluene-ethylbenzene.

[0088] Preferably, the ionic liquid may be selected from one or more of haloalkylpyridines, haloalkylimidazolines, or haloalkylarylammonium salts. For example, the ionic liquid may be selected from 1-ethyl-3-methylimidazolium chloride [EMIMCl].

[0089] The present invention has no special requirements for the leveling agent, brightening agent, stabilizer, acid or base contained in the electrolyte, and leveling agents, brightening agents, stabilizers, acids or bases commonly used in the art can be used. As an example, the leveling agent can be selected from one or more of metals such as cobalt, manganese, nickel, sugars such as glucose, sulfur- and phosphorus-containing organic compounds, etc.; the brightening agent can be selected from aldehydes, ketones, organic compounds containing double or triple bonds, heterocyclic compounds or metals, such as ethylene thiourea, dithiobenzimidazole, tetrahydrothiazolethione, benzalacetone, o-chlorobenzaldehyde, benzaldehyde, phenylenol (BPC), etherification products of butynediol and propargyl alcohol, saccharin (o-sulfobenzoimide), etc.; the stabilizer can be selected from compounds of S, Se, Te, such as oxygen-containing compounds, heavy metal ions such as Pb 2+ , Sn 2+ , Sb 3+ , Cd 2+ , etc., one or more of water-soluble organic compounds such as alcohols, ketones, amines, etc.; the acid can be selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, chromic acid, etc.; and the base can be selected from one or more of sodium hydroxide, soda ash, sodium silicate, sodium tripolyphosphate, etc.

[0090] The present invention also has no special requirements for the concentrations of the leveling agent, brightening agent, stabilizer, acid or base contained in the electrolyte, and concentration ranges commonly used in the art can be used. As an example, the concentration of each of the leveling agent, brightening agent, stabilizer, acid or base can be 1-100 g / L.

[0091] Step (c)

[0092] In step (c), at least the deposition region on the second side of the self-supporting electrode membrane is brought into contact with the electrolyte, and an electrodeposition reaction is carried out in the deposition region, so as to deposit a current collector of the metal to be deposited on the second side, wherein the electrodeposition temperature is 0 to 70 °C, preferably 0 to 30 °C, more preferably 0 to 20 °C, and even more preferably 0 to 10 °C.

[0093] The inventors surprisingly found that when preparing an electrode by electrodeposition on an electrode membrane, controlling the electrodeposition temperature (i.e., the electrolyte temperature) within a specific range, especially within a relatively low temperature range, can improve the initial discharge specific capacity, initial Coulombic efficiency and cycling performance of the active material contained in the electrode. When the electrodeposition temperature is in the range of 0 to 20 °C, preferably 0 to 10 °C, further improved initial discharge specific capacity, initial Coulombic efficiency and cycling performance can be achieved.

[0094] In an embodiment, the electrodeposition temperature may be from 0 to 70 °C, preferably from 0 to 30 °C, more preferably from 0 to 20 °C, still more preferably from 0 to 10 °C. For example, it may be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58, 60, 62, 65, 68, 70 °C, or within the range defined by any two of them.

[0095] It is readily understood by those skilled in the art that the electrodeposition process can be carried out by methods commonly used in the art. For example, a self-supporting electrode film can be used as the cathode, a current collector metal as the anode or a metal sheet or foil containing the current collector metal as the anode, and the cathode and anode are placed in the electrolyte. Then, a circuit is formed with an external power supply through an external circuit, where the cathode is connected to the negative pole of the power supply and the anode is connected to the positive pole of the power supply. Under the action of current, the anode dissolves and the corresponding metal is deposited on the surface of the cathode.

[0096] The present invention has no special requirements for other process conditions of the electrodeposition process, and the process conditions commonly used by those skilled in the art can be used.

[0097] In some embodiments, the current used in the electrodeposition process can be selected from any one of direct current constant current, pulse, square wave, triangular wave, sine wave, or their superimposed forms.

[0098] In some embodiments, the current density used in the electrodeposition process can be 0.1 - 10 A / dm 2 , for example 0.5 - 8 A / dm 2 .

[0099] In some embodiments, the electrodeposition time used in the electrodeposition process can be 30 - 1800 seconds, for example 50 - 1500 seconds. By way of example, the electrodeposition time can be 30, 50, 80, 100, 120, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1500, 1600, 1800 seconds, or within the range defined by any two of them.

[0100] In some embodiments, the thickness of the current collector formed by electrodeposition can be 0.1 - 20.0 μm, such as 0.5 - 15.0 μm. As an example, the thickness of the current collector formed by electrodeposition can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0 μm, or within the range defined by any two of them.

[0101] In some embodiments, the electrodeposition process can be carried out in an air atmosphere, or in a vacuum or in an atmosphere of one or more selected from argon, nitrogen, or a mixed gas thereof. Considering economic costs, the electrodeposition process is preferably carried out in an air atmosphere.

[0102] It is easy for those skilled in the art to understand that after the electrodeposition process is completed, the prepared electrode can be separated from the optional auxiliary conductor and the optional protective layer.

[0103] In some embodiments, the prepared electrode can also be cleaned and dried. As an example, the prepared electrode can be placed in water or an organic solvent for thorough cleaning, such as cleaning 1 - 5 times. Optionally, the cleaned electrode can be dried under air, argon, nitrogen or vacuum conditions by using air flow blowing or / and heating to volatilize the residual solvent on the surface, thereby obtaining a dried electrode.

[0104] Electrode

[0105] The second aspect of the present invention provides an electrode prepared by the electrode preparation method according to the first aspect of the present invention.

[0106] Energy storage device

[0107] The third aspect of the present invention provides an energy storage device, which includes the electrode according to the second aspect of the present invention.

[0108] The electrode can be the positive electrode and / or the negative electrode of the energy storage device.

[0109] In some embodiments, the energy storage device can be a lithium-ion secondary battery. For a lithium-ion secondary battery, in the case of depositing a positive electrode current collector, the positive electrode active material in the self-supporting electrode film can be 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 with an olivine structure, preferably LiMn2 O 4 , LiNiMnCoO 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.5 Co 0.3 Mn 0.2 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 and LiFePO 4 one or more of; in the case of depositing the negative electrode current collector, the negative electrode active material in the self-supporting electrode film may be selected from one or more of natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon-based materials, tin-based materials, lithium titanate, and metallic lithium, preferably one or more of graphite and silicon-based materials, more preferably one or more of graphite, silicon-carbon composites, and silicon alloys.

[0110] In some embodiments, the energy storage device may be a sodium ion secondary battery. For a sodium ion secondary battery, in the case of depositing the positive electrode current collector, the positive electrode active material may be selected from one or more of layered transition metal oxides or Prussian blue analogs, preferably NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O 2 , Na 2 FeP 2 O 7 , Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) , Na 3 V 2 (PO 4 ) 3 , NaFePO 4 and NaMnFe(CN) 6one or more of; in the case of depositing a negative electrode current collector, the negative electrode active material may be selected from one or more of natural graphite, artificial graphite, mesophase microcarbon microbeads (MCMB), hard carbon, soft carbon, silicon-based materials, and tin-based materials, preferably one or more of graphite and silicon-based materials, more preferably one or more of graphite, silicon-carbon composites, and silicon alloys.

[0111] In some embodiments, the energy storage device may be a supercapacitor. For a supercapacitor, in the case of depositing a positive electrode current collector, the positive electrode active material may be selected from one or more of metal oxides, conductive polymers, and carbon materials, preferably MnO 2 , NiO, Co 3 O 4 , polyaniline, polypyrrole, activated carbon, graphene, and biochar; in the case of depositing a negative electrode current collector, the negative electrode active material may be selected from one or more of metals, carbon materials, conductive polymers, metal oxides, and metal-organic framework (MOF) derived materials, preferably one or more of aluminum, zinc, activated carbon, graphite, polyaniline, polypyrrole, polythiophene, and MnO 2 one or more of.

[0112] Electrode production system

[0113] The fourth aspect of the present invention provides an electrode production system for performing the method according to the first aspect of the present invention, comprising:

[0114] A self-supporting electrode film providing module for providing a self-supporting electrode film, the self-supporting electrode film including a first side and a second side opposite to the first side, the second side including a deposition region on which a metal is deposited when in contact with an electrolyte for an electrodeposition reaction;

[0115] An optional surface cleaning and treatment module, located upstream of the electrodeposition module, for cleaning and treating the surface of the self-supporting electrode film;

[0116] An electrolyte providing module for providing an electrolyte for electrodeposition to the electrodeposition module;

[0117] A temperature control module for controlling the temperature of the electrodeposition module to control the electrodeposition temperature to be 0 to 70 °C, preferably 0 to 30 °C, more preferably 0 to 20 °C, and more preferably 0 to 10 °C;

[0118] An electrodeposition module, located downstream of the self-supporting electrode film providing module and the electrolyte providing module, for depositing a current collector on the second side of the self-supporting electrode film;

[0119] An optional cleaning and drying module, located downstream of the electrodeposition module, for cleaning and drying the prepared electrode;

[0120] A transfer module for moving a self-supporting electrode film between various modules of an electrode production system; and

[0121] An optional collection and conveyance module for collecting and conveying the prepared electrodes.

[0122] The electrode production system of the present invention has the advantages of simple process, high production efficiency, low energy consumption, no pollution, and can be easily combined with the production equipment commonly used in the prior art, which is conducive to realizing continuous and large-scale production.

[0123] Figure 12 It is a schematic diagram of an embodiment of the electrode production system of the present invention. Refer to Figure 12 , the electrode production system of the present invention includes a self-supporting electrode film providing module (120, which provides a self-supporting electrode film 120'), an electrolyte providing module (not shown), a temperature control module (not shown), a transfer module, and an electrodeposition area 100 (which includes a cathode 120' (self-supporting electrode film) and an anode 110).

[0124] In a typical embodiment, the self-supporting electrode film provided by the self-supporting electrode film providing module is transferred to the electrodeposition module by the transfer module, and then contacts the electrolyte provided by the electrolyte providing module in the electrodeposition module, and electrodeposition occurs. During electrodeposition, the temperature control module controls the temperature of electrodeposition.

[0125] In some embodiments, the electrode production system of the present invention further includes an optional surface cleaning and treatment module, which is located upstream of the electrodeposition module and is used for cleaning and treating the surface of the self-supporting electrode film. For the specific cleaning and treatment process, refer to the description of step (a) above, and details will not be repeated here.

[0126] In some embodiments, the electrode production system of the present invention further includes an optional cleaning and drying module 200, which is located downstream of the electrodeposition module and is used for cleaning and drying the prepared electrodes. For the specific cleaning and drying process, refer to the description of step (a) above, and details will not be repeated here.

[0127] In some embodiments, the electrode production system of the present invention further includes an optional collection and conveyance module for collecting and conveying the prepared electrodes.

[0128] In some embodiments, the electrode production system of the present invention further includes an optional auxiliary conductor setting module, which is located downstream of the self-supporting electrode film providing module and the optional surface cleaning and treatment module and upstream of the electroplating module, and is used to set an auxiliary conductor on at least a part or all of a first region on the first side of the self-supporting electrode film. The first region is a corresponding region opposite to the deposition region on the second side, and the auxiliary conductor contacts the first region during electroplating. For the specific description of the auxiliary conductor, refer to the description of step (a) above, and details will not be repeated here.

[0129] In some embodiments, the electrode production system of the present invention further includes:

[0130] An optional protective layer setting module 310, which is located downstream of the self-supporting electrode film providing module and the optional auxiliary conductor setting module and upstream of the electroplating module, and is used to set a protective layer on at least the first region on the first side of the self-supporting electrode film. The protective layer is used to protect the first side from depositing a current collector during electroplating;

[0131] An optional separation module, which is located downstream of the electroplating module and is used to remove the optional auxiliary conductor and the optional protective layer;

[0132] An optional protective layer recycling module 320, which is located downstream of the optional separation module and is used to transfer the separated protective layer to the optional protective layer setting module 310 for reuse; and

[0133] An optional rolling module, which may include a first part and an optional second part. The first part is located upstream of the self-supporting electrode film providing module and is used to roll the self-supporting electrode film. The optional second part is located downstream of the optional separation module and is used to roll the produced electrode.

[0134] In some embodiments, the starting end of the optional protective layer setting module 310 is connected to the end of the optional protective layer recycling module 320, so as to realize the recycling of the protective layer.

[0135] Figure 13 Another embodiment of the electrode production system of the present invention is shown. Refer to Figure 13 , the electrode production system further includes a rolling module, which includes a first part and an optional second part. The first part is located upstream of the self-supporting electrode film providing module and is used to roll the self-supporting electrode film. The optional second part is located downstream of the optional separation module and is used to roll the produced electrode. In some embodiments, the rolling module may only include the first part.

[0136] In some embodiments, the electrode production system of the present invention may further include other modules upstream of the self-supporting electrode film providing module for mixing, fibrillating, etc. the raw materials of the self-supporting electrode film.

[0137] In some embodiments, the electrode production system of the present invention is a continuous production system.

[0138] In some embodiments, the electrode production system of the present invention is an automated production system. It is easy for those skilled in the art to understand that automatic sampling devices for self-supporting electrode films, electrolytes, anodes for electrodeposition, etc. can be used as required to achieve automated production.

[0139] Example

[0140] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0141] Example 1: The thickness and weight of the current collector and their respective proportions of the thickness and weight of the entire electrode

[0142] Prepare a self-supporting graphite electrode film according to the following method: Mix graphite (S360-L2-H), conductive carbon black (TIMCAL Super P Li), polytetrafluoroethylene (MSK-F104), and polyvinylidene fluoride (HSV900) in a mass ratio of 85:5:5:5 and disperse evenly by ball milling at 600 rpm for 60 min. Then, under the conditions of 180 °C and 200 kgf / cm 2 Perform multiple roll extrusions to the target parameters (to a film thickness of 100 μm).

[0143] Preparation of the negative electrode: Prepare a mixed aqueous solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at a concentration of 20 g / L, and sulfuric acid at a concentration of 65 g / L as the electrolyte for copper plating on the negative electrode surface. Stick an insulating PE film on one surface of the self-supporting graphite electrode film prepared as above. Then immerse the graphite film with the insulating PE film attached and the copper foil together in the prepared electrolyte. Use the graphite film with the insulating PE film attached as the cathode and the copper foil as the anode. Use direct current as the power source and use a current density of 2.5 A / dm 2 to perform electrodeposition at 0 °C for 100 seconds. Then take out the graphite film with the insulating PE film attached, remove the insulating PE film, and after drying, obtain negative electrode 1 with an electrodeposited current collector thickness of 1.2 μm. Correspondingly, the self-supporting graphite electrode film prepared as above is at 180 °C and 500 kgf / cm 2Under the condition of [specific condition not provided in the original], it was thermocompression laminated with a 9-μm carbon-coated copper foil (8-μm copper + 1-μm carbon, purchased from Shenzhen Kejing Co., Ltd. (MTI)) to obtain the negative electrode 2.

[0144] Preparation of half-cells: The negative electrode 1 and the negative electrode 2 were respectively cut into circular wafers with a diameter of 14 mm, vacuum dried at 80 °C for 12 h, and then transferred to a glove box filled with argon (water and oxygen content < 0.5 ppm). The negative electrode, Celgard 2350 separator, lithium sheet, stainless steel gasket, and stainless steel spring piece were successively placed in a CR2032 coin cell case. Subsequently, 25 μL of electrolyte (the electrolyte is a 1 M LiPF 6 solution in the following mixed solvent: Among them, ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1, and 10% fluoroethylene carbonate (FEC) and 1% vinylene carbonate (VC) were added based on the total volume fraction of EC + DEC). After laminating the sheets, hydraulic encapsulation was carried out, and it was left standing for 12 h to allow the electrolyte to fully infiltrate into the pores of the electrode, thereby obtaining the coin half-cell 1 and the coin half-cell 2.

[0145] Charge-discharge test: At a temperature of 30 °C, the CR2032 coin half-cells 1 and 2 were lithiated with a constant current at a rate of 0.2C to 0.005 V, then left standing for 5 min, and then delithiated with a constant current at a rate of 0.5C to 2.0 V. This is one charge-discharge cycle. The discharge capacity and charge capacity during the first charge-discharge cycle were recorded as the first discharge capacity and the first charge capacity. Similarly, the discharge capacity and charge capacity during the nth cycle were respectively recorded as the discharge capacity and charge capacity of the nth cycle. Dividing the first discharge capacity by the first charge capacity and multiplying by 100% gives the first Coulombic efficiency.

[0146] Table 1 lists the thickness and weight of the current collectors of the negative electrode 1 and the negative electrode 2 and their respective proportions in the corresponding overall negative electrodes.

[0147] Table 1: Thickness and weight of the current collectors of the negative electrode 1 and the negative electrode 2 and their respective proportions in the thickness and weight of the overall negative electrodes

[0148]

[0149] As can be seen from Table 1, compared with the traditional current collectors obtained by thermocompression lamination, the ultra-thin current collectors obtained by electrodeposition can significantly reduce the thickness and weight of the current collector layer and their proportions in the thickness and weight of the overall electrode, thereby significantly increasing the proportion of the active material in the electrode.

[0150] Figure 3 Shows the first charge-discharge curves at a constant current of the coin half-cell 1 and the coin half-cell 2. Combining Figure 1, the initial Coulombic efficiencies of the button half-cell 1 and the button half-cell 2 are 80.81% and 73.02% respectively. This indicates that the electrodes prepared by the method of the present invention have a higher initial Coulombic efficiency.

[0151] Figure 4 Figures 4a and 4b respectively show Figure 4 the negative electrode 1 ( Figure 4 b) and the negative electrode 2 ( Figure 4 a) after 100 charge-discharge cycles. As can be seen from

[0152] Example 2: Electroplating time

[0153] Prepare a mixed aqueous solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at a concentration of 20 g / L, and sulfuric acid at a concentration of 65 g / L as the electrolyte for copper plating on the surface of the negative electrode. Stick an insulating PE film on one side of the self-supporting graphite electrode film prepared in Example 1. Then immerse the graphite electrode film and the copper foil together in the electrolyte and connect them to a power supply to form a two-electrode system, where the graphite electrode film is used as the cathode and the copper foil is used as the anode. Use direct current as the power supply and use a current density of 2.5 A / dm 2 to perform electroplating at 0 °C for 100 seconds. Then take out the graphite film with the insulating PE film attached, remove the insulating PE film, and dry it to obtain the negative electrode 3 including the electroplated current collector. Record the deposition amount of copper on the surface of the graphite electrode and the relationship between the covering effect and the deposition time.

[0154] Figure 5 Figure 6 shows the change of the areal density (mg / cm 2 ) and the thickness during the preparation process of the negative electrode 3 with the electroplating time. As can be seen from Figure 5 it, as the electroplating time increases, both the thickness and the areal density of the electroplated current collector increase; when the electroplating time reaches 600 seconds, the areal density and thickness close to those of the commercial copper foil (purchased from Shenzhen Kejing Company (MTI), the same below) can be basically achieved.

[0155] Figure 6 Figures 6a and 6b respectively show the change of the electroplating covering effect during the preparation process of the negative electrode 3 with the electroplating time ( Figure 6 a: 60 seconds, Figure 6 b: 120 seconds). Figure 6 Figures 6a and Figure 6 6b show that at 60 seconds of electroplating, the electroplated current collector has not completely covered the self-supporting graphite electrode film; at 120 seconds of electroplating, the electroplated current collector has completely covered the self-supporting graphite electrode film.

[0156] Combined with Figure 5 and Figure 6 a - 6b, it can be seen that the method of the present invention can quickly achieve uniform coverage of the ultra - thin current collector on the surface of the self - supporting electrode film, which is suitable for large - scale application.

[0157] Example 3: Uniformity of electrodeposited current collector

[0158] Provide the self - supporting graphite electrode film prepared in Example 1 and cut it into strips of 2×10 cm. Prepare a mixed aqueous solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at 20 g / L, and sulfuric acid at 65 g / L as the electrolyte for copper plating on the negative electrode surface. Divide the strips of the self - supporting graphite electrode film into 2 groups, with 1 strip in each group. One group is pasted with an insulating PE film on one side, and the other group is pasted with an auxiliary conductive copper foil of equal area on one side and then conformally pasted with an insulating PE film. Immerse the 2 long - strip electrode films vertically into the electrolyte with 4 / 5 of their area, and connect them to a two - electrode system with a power supply, where the self - supporting graphite electrode film is used as the cathode and the copper foil is used as the anode. Use direct current as the power supply, and use a current density of 2.5 A / dm 2 , and perform electrodeposition at 0 °C for 600 seconds. After the electrodeposition is completed, take out the graphite film with the insulating PE film attached, remove the insulating PE film, rinse it 3 times with deionized water, and dry it to obtain negative electrode 4; after the electrodeposition is completed, take out the graphite film with both the auxiliary conductive copper foil and the insulating PE film attached, remove the auxiliary conductive copper foil and the insulating PE film, rinse it 3 times with deionized water, and dry it to obtain negative electrode 5. Divide the parts of negative electrode 4 and negative electrode 5 immersed in the electrolyte into upper, middle, and lower sections, and record the thickness (average value of the samples) of the copper current collectors deposited in each of the upper, middle, and lower sections respectively.

[0159] Preparation of button half - cells: Assemble negative electrode 4 and negative electrode 5 into button half - cells respectively according to the method in Example 1. Then perform 100 charge - discharge cycle tests, with other conditions the same as in Example 1 except that the charge - discharge rate is 1C.

[0160] Discharge specific capacity: Take the discharge capacity of each cycle as the numerator and the weight (dry weight) of the active material in the positive electrode active material layer of the battery as the denominator, and divide the two to obtain the discharge specific capacity.

[0161] Table 2 lists the thickness, average thickness, and variance of the upper, middle, and lower sections of negative electrode 4 and negative electrode 5 respectively.

[0162] Table 2: Thickness, average thickness, and variance of the upper, middle, and lower sections of negative electrode 4 and negative electrode 5

[0163]

[0164] As can be seen from Table 2, compared with the negative electrode 4 with only the insulating PE film set during the electrodeposition process, the upper, middle, and lower sections of the negative electrode 5 with both the insulating PE film and the auxiliary conductive copper foil set during the electrodeposition process have greater thicknesses, and the variance of the thickness is smaller. This indicates that by setting an auxiliary conductor on the opposite side of the self-supporting electrode film where electrodeposition occurs during the electrodeposition process, it helps to improve the deposition rate and deposition uniformity.

[0165] Table 3 lists the test results of the electrochemical performance of the button half-cells assembled from the negative electrode 4 and the negative electrode 5 respectively.

[0166] Table 3: Test Results of the Electrochemical Performance of the Button Half-Cells Assembled from the Negative Electrode 4 and the Negative Electrode 5

[0167]

[0168] The button half-cell assembled from the negative electrode 5 has an initial discharge specific capacity of approximately 263.4 mAh / g, while the button half-cell assembled from the negative electrode 4 only has an initial discharge specific capacity of approximately 249.7 mAh / g. This is unexpected because the negative electrode active materials used in the negative electrode 4 and the negative electrode 5 are the same, and it is generally considered that their discharge specific capacities should be the same, but the results show that the button half-cell assembled from the negative electrode prepared by the method of the present invention has a higher discharge specific capacity. This indicates that the electrode preparation method of the present invention is beneficial to improving the discharge specific capacity of the active material.

[0169] In addition, the button half-cell assembled from the negative electrode prepared by the method of the present invention also has a higher specific capacity retention rate, which indicates that the electrode preparation method of the present invention is beneficial to improving the cycling performance.

[0170] Example 4: Interface Bonding between the Self-Supporting Electrode Film and the Current Collector

[0171] A commercial current collector (copper foil purchased from Shenzhen Kejing Company (MTI)) is provided.

[0172] A current collector with the same thickness as the commercial current collector is prepared by electrodeposition. The specific method is as follows: The self-supporting graphite electrode film prepared in Example 1 is provided, and an insulating PE film is attached to one side thereof. A mixed aqueous solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at a concentration of 20 g / L, and sulfuric acid at a concentration of 65 g / L is prepared as the electrolyte for copper plating on the surface of the graphite self-supporting electrode film. The graphite self-supporting electrode film attached with the insulating PE film and the copper foil are immersed in the electrolyte together and connected to a power supply to form a two-electrode system, where the graphite self-supporting electrode film attached with the insulating PE film is used as the cathode and the copper foil is used as the anode. Direct current is used as the power supply, and a current density of 2.5 A / dm 2 is used for electrodeposition at 0 °C for 720 seconds. Then it is washed 3 times with deionized water and dried to obtain the negative electrode 6.

[0173] The 180° peeling test was carried out on the negative electrode 2 and the negative electrode 6 using a universal testing machine (ZWICK Z020) according to the following method: Fix the active material surface of the composite electrode to be tested on a horizontally placed substrate, and attach a test tape to the current collector side. Fix the tape and the substrate to the universal testing machine ZWICK Z020 through clamps respectively, with both ends at 180°. Tensile at a rate of 5 cm / min, that is, conduct current collector peeling on the electrode surface, and record the peeling force and displacement information.

[0174] Figure 7 a and 7b respectively show the cross-sectional scanning electron microscope images of the negative electrode 2 ( Figure 7 b) and the negative electrode 6 ( Figure 7 a). The cross-sectional scanning electron microscope test was carried out using a Zeiss Gemini electron microscope, and the test conditions were: magnification 3k, acceleration voltage 5kV.

[0175] From Figure 7 it can be seen that for the commercial current collector obtained by traditional lamination and composite, even under high temperature and high pressure lamination and composite, inevitable delamination still occurred. In contrast, the current collector obtained by electrodeposition has a closer combination with the self-supporting electrode film. This is manifested mechanically as the peeling strength of the negative electrode 6 being significantly higher than that of the negative electrode 2 (see Table 4).

[0176] Table 4: Comparison of the bonding force between the commercial current collector and the electrodeposited current collector

[0177] Electrode Peak stripping force / N Average stripping force / N Negative electrode 2 8.426 5.753 Negative electrode 6 13.735 10.442

[0178] Example 5: Internal resistance of the electrode

[0179] The internal resistances of the negative electrode 1 and the negative electrode 2 prepared in Example 1, and the self-supporting electrode film prepared in Example 1 alone (i.e., not composite with any current collector) were tested using a two-probe system (the principle is as Figure 8 , Yuaneng BER2500).

[0180] Table 5: Comparison of internal resistances

[0181] Electrode Internal resistance / mΩ Negative electrode 1 8.1 Negative electrode 2 23.5 Separate self-supporting electrode film 6.8

[0182] See Figure 8 , the resistance value measured by the two-probe method for the internal resistance of the electrode can be split into the intrinsic resistance R of the self-supporting electrode film 电极膜 , the intrinsic resistance R of the foil (current collector) 箔材 , the contact resistance R' between the self-supporting electrode film and the upper probe A 电极膜-A , the contact resistance R' between the electrode film and the foil 电极膜-箔材 , the contact resistance R' between the foil and the lower probe B 箔材-B and the sum R总 。

[0183] Referring to Table 5, compared with the single self-supporting electrode film, the total internal resistance of the negative electrode 1 prepared by electrodeposition only increases slightly, while the internal resistance of the negative electrode 2 prepared by traditional lamination composite increases to about 3 times. This indicates that the use of electrodeposition method to prepare the current collector can simultaneously achieve less consumption of metal materials and lower electrode internal resistance, improving the economy and energy efficiency of the battery.

[0184] Example 6: Electrode Impedance

[0185] The button half-cell 1 and button half-cell 2 prepared in Example 1 were used for AC impedance testing. The assembled button half-cell 1 and button half-cell 2 were charged and discharged at a rate of 0.1C in the voltage range of 0.005 - 1.5V for 3 charge-discharge cycles and then lithiated to the state of SOC (State of Charge) 50% for impedance testing.

[0186] Electrochemical impedance measurement was carried out using a Chenhua CHI660e electrochemical workstation under the following conditions: frequency range from 100 kHz to 0.01 Hz, and the amplitude of the AC voltage was 10 mV.

[0187] Figure 9 The impedance test results of the button half-cell 1 and button half-cell 2 are shown. Referring to Figure 9 , the impedance of the button half-cell 1 is about 15 Ω, while the impedance of the button half-cell 2 is about 22 Ω. This indicates that the electrode prepared by the electrodeposited current collector has better interfacial contact and thus smaller interfacial impedance.

[0188] Example 7: Application of Lithium-Ion Battery - Electrode Cycling

[0189] The negative electrodes 1 and 2 prepared in Example 1 were used as the negative electrodes of the lithium-ion secondary battery.

[0190] Preparation of self-supporting lithium iron phosphate electrode film: Lithium iron phosphate (P198 - S20), conductive carbon black (TIMCAL SuperP Li), polytetrafluoroethylene, and polyvinylidene fluoride were ball-milled at a mass ratio of 85:5:5:5 for 60 min at a rotation speed of 600 rpm until evenly dispersed. Then, it was roll-extruded multiple times at 180 °C and 200 kgf / cm 2 to the target parameters (the thickness of the film was 150 μm).

[0191] The positive electrode of a lithium-ion secondary battery is prepared as follows: Inside a glove box, aluminum chloride powder is added to the ionic liquid 1-ethyl-3-methylimidazolium chloride [EMIMCl] at a molar ratio of aluminum chloride to ionic liquid of 1.3:1. After stirring and dissolving, an electrolyte for aluminum electrodeposition is obtained. One side of the self-supporting lithium iron phosphate electrode film prepared as above is pasted with an insulating PE film, and together with an aluminum foil (purchased from Shenzhen Kejing Company (MTI), the same below), it is immersed in the electrolyte and connected to a power supply to form a two-electrode system, where the lithium iron phosphate film serves as the cathode and the aluminum foil serves as the anode. Direct current is used as the power supply, and a current density of 3.5 A / dm 2 is applied for electrodeposition at 25 °C for 180 seconds. After that, the self-supporting lithium iron phosphate electrode film with the insulating PE film attached is taken out, the insulating PE film is removed, and after drying, the positive electrode 1 with an electrodeposited current collector thickness of 2 μm is obtained. Correspondingly, the self-supporting lithium iron phosphate electrode film is thermocompression laminated with a 16-μm carbon-coated aluminum foil (15-μm aluminum + 1-μm carbon) under the conditions of 180 °C and 500 kgf / cm 2 to obtain the positive electrode 2.

[0192] Lithium-ion battery assembly: The negative electrodes 1 and 2 are cut into circular pieces with a diameter of 14 mm, and the positive electrodes 1 and 2 are cut into circular pieces with a diameter of 13 mm. After vacuum drying at 80 °C for 12 h, they are transferred to an argon-filled glove box (water and oxygen content < 0.5 ppm). The positive electrode, Celgard 2350 separator, negative electrode, stainless steel gasket, and stainless steel spring piece are sequentially placed into a CR2032 button battery case. 25 μL of electrolyte (the electrolyte is a 1 M solution of LiPF 6 in the following mixed solvent: ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed at a volume ratio of 1:1, and 10% fluoroethylene carbonate (FEC) and 1% vinylene carbonate (VC) are added based on the total volume fraction of EC + DEC)) is dropped on both sides of the separator. After lamination, hydraulic encapsulation is carried out, and it is left standing for 12 h to allow the electrolyte to fully infiltrate into the electrode pores. The positive electrode 1 and the negative electrode 1 form the full cell 1, and the positive electrode 2 and the negative electrode 2 form the full cell 2.

[0193] Charge-discharge cycle test: First, the prepared full cells 1 and 2 are subjected to 3 charge-discharge cycles at a rate of 0.1C to activate the electrode materials, where the discharge cut-off voltage is 2.5 V and the charge cut-off voltage is 3.7 V. After each charge or discharge process is completed, it is left standing for 5 min before proceeding to the next process. After activation, cyclic charge-discharge tests are carried out at a rate of 0.5C for 100 cycles (the charge-discharge cut-off voltages are the same as those in the activation process).

[0194] The energy density of the full cell can be calculated by using the measured discharge capacity, the charge and discharge cut-off voltages, and taking the mass of the electrode (including the current collector) as the denominator. For the discharge specific capacity, the discharge capacity of each cycle is used as the numerator, and the weight (dry weight) of the active material contained in the positive electrode active material layer of the cell is used as the denominator, and the two are divided to obtain the discharge specific capacity.

[0195] Figure 10 The variation of the discharge specific capacity and energy density of full cell 1 and full cell 2 with the number of cycles is shown. From Figure 10 It can be seen that compared with full cell 2, full cell 1 has a higher energy density throughout the cycle.

[0196] In addition, full cell 1 has an initial discharge specific capacity of about 150 mAh / g, while full cell 2 only has an initial discharge specific capacity of about 100 mAh / g. This is unexpected because the positive electrode active materials used in full cell 1 and full cell 2 are the same, and it is generally considered that the discharge specific capacities of the two should be close, but the results show that full cell 1 has a significantly higher discharge specific capacity than full cell 2. This indicates that the electrode preparation method of the present invention is beneficial to improving the discharge specific capacity of the active material.

[0197] Example 8: Influence of electrodeposition temperature

[0198] The negative electrodes 9, 10, 11, and 12 were prepared in the same manner as the negative electrode 1 in Example 1, except for the following: the electrodeposition temperatures were 70 °C, 30 °C, 10 °C, and 0 °C, respectively. Button half-cells were assembled respectively according to the button half-cell assembly method in Example 1, and charge and discharge cycle tests were carried out at a rate of 0.5C according to the method in Example 7.

[0199] Figure 11 Pictures of the negative electrodes prepared at different electrodeposition temperatures are shown, where the negative electrodes 9, 10, 11, and 12 are from left to right in sequence.

[0200] The charge and discharge cycle test results of the button half-cells assembled from the negative electrodes 9, 10, 11, and 12 are summarized in Table 8.

[0201] Table 8: Charge and discharge cycle test results of button half-cells

[0202]

[0203] As can be seen from Table 8, the electrodeposition temperature has a great influence on the discharge specific capacity and cycling performance of the button half-cells assembled with the prepared electrodes. Unexpectedly, as the electrodeposition temperature gradually decreases, the initial discharge specific capacity, the discharge specific capacity after 50 cycles, and the specific capacity retention rate of the button half-cells assembled with the prepared electrodes all gradually increase, indicating that a lower electrodeposition temperature is beneficial to improving the initial discharge specific capacity and cycling performance.

[0204] Example 9: Roughness of the self-supporting electrode film

[0205] A self-supporting graphite electrode film with a surface roughness of 0.02 μm was prepared as follows: The self-supporting graphite electrode film prepared in Example 1 was roll-extruded to the target parameters (surface roughness of 0.02 μm).

[0206] A self-supporting graphite electrode film with a surface roughness of 0.2 μm was prepared as follows: The surface roughness of the self-supporting graphite electrode film prepared in Example 1 was adjusted to 0.2 μm by plasma etching under the following conditions: The process gas was argon, the argon rate was 40 sccm, the current was 0.1 A, the gas pressure was 2 mTorr, and the etching time was 300 s.

[0207] An aqueous mixed solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at a concentration of 20 g / L, and sulfuric acid at a concentration of 65 g / L was prepared as the electrolyte for copper plating on the negative electrode surface. The self-supporting graphite electrode films with surface roughnesses of 0.02 μm and 0.2 μm were respectively pasted with an insulating PE film on one side, and then immersed in the electrolyte together with copper foil, and connected to a power supply to form a two-electrode system, where the self-supporting graphite electrode film was used as the cathode and the copper foil was used as the anode. Electric power was used as the power supply, and a current density of 2.5 A / dm 2 was used for electrodeposition at 0 °C for 100 seconds. Then, the self-supporting graphite electrode films with the insulating PE film attached were taken out, the insulating PE film was removed, and after drying, the negative electrode 13 (corresponding to the self-supporting graphite electrode film with a roughness of 0.02 μm) and the negative electrode 14 (corresponding to the self-supporting graphite electrode film with a roughness of 0.2 μm) with an electrodeposited current collector thickness of 1 μm were obtained. Correspondingly, the self-supporting graphite electrode films were thermally laminated with 9-μm carbon-coated copper foil (8-μm copper + 1-μm carbon, purchased from Shenzhen Kejing Company (MTI)) under the conditions of 180 °C and 500 kgf / cm 2 to obtain the negative electrode 15 (corresponding to the self-supporting graphite electrode film with a roughness of 0.02 μm) and the negative electrode 16 (corresponding to the self-supporting graphite electrode film with a roughness of 0.2 μm).

[0208] The half-cells were assembled according to the method in Example 1 and cycled for charge and discharge 100 times at a rate of 0.5C. The test results are summarized in Table 9.

[0209] Table 9: Influence of Roughness

[0210]

[0211] As can be seen from Table 9, for the self-supporting graphite electrode film with a surface roughness of 0.02 μm, the half-cell corresponding to the negative electrode 13 prepared by electrodeposition from it is superior to the negative electrode 15 prepared by hot pressing and compounding from it in terms of the initial specific capacity, the remaining specific capacity after 100 cycles, and the specific capacity retention rate. A similar rule can also be found from the comparison between the negative electrode 14 and the negative electrode 16. However, compared with the case when the surface roughness is 0.02 μm, when the surface roughness is 0.2 μm, the improvement amplitude of the method of the present invention for properties such as the initial specific capacity is greater than that of hot pressing and compounding.

[0212] Example 10: Application in Supercapacitors

[0213] Preparation of self-supporting activated carbon electrode film: The self-supporting activated carbon electrode film was prepared according to the same preparation method as the self-supporting graphite electrode film in Example 1, except for the following: graphite was replaced with activated carbon (YP-80F).

[0214] In the glove box, aluminum chloride powder was added to the ionic liquid 1-ethyl-3-methylimidazolium chloride [EMIMCl] at a molar ratio of aluminum chloride: ionic liquid of 1.3:1, and after stirring and dissolving, an aluminum-plated electrolyte was obtained. The self-supporting activated carbon electrode film prepared as above was adhered with an insulating PE film on one side, and together with the aluminum foil, it was immersed in the electrolyte and connected to a power supply to form a two-electrode system, where the self-supporting activated carbon electrode film was used as the cathode and the aluminum foil was used as the anode. Direct current was used as the power supply, and a current density of 3.5 A / dm 2 was used for electrodeposition at 25 °C for 180 seconds. Then, the self-supporting activated carbon electrode film adhered with the insulating PE film was taken out, the insulating PE film was removed, and after drying, electrode a with an electrodeposited current collector thickness of 2 μm was obtained. Correspondingly, the self-supporting activated carbon electrode film was hot-pressed and laminated with a 16-μm carbon-coated aluminum foil (15-μm aluminum + 1-μm carbon) under the conditions of 180 °C and 500 kgf / cm 2 to make electrode b.

[0215] Electrode a and electrode b were transferred out of the glove box, washed three times and then dried overnight under vacuum (80 °C). The prepared electrode a and electrode b were respectively assembled into symmetric supercapacitor 1 and supercapacitor 2, and the electrolyte used was an aqueous solution of 6M KOH.

[0216] The specific capacitance (with the mass of the active material, excluding the mass of the current collector, as the denominator) and energy density (with the mass of the electrode including the current collector as the denominator) of supercapacitor 1 and supercapacitor 2 were tested according to the national standard GBT34870.1-2017.

[0217] Table 10 lists the properties of electrode a and electrode b.

[0218] Table 10: Properties of Activated Carbon Electrodes

[0219]

[0220] Table 11 lists some performances of supercapacitor 1 and supercapacitor 2.

[0221] Table 11: Supercapacitor Performances

[0222] Supercapacitor Specific capacitance of activated carbon (F / g) Overall energy density of supercapacitor / (Wh / kg) Supercapacitor 1 298 8.53 Supercapacitor 2 285 6.85

[0223] As can be seen from Table 11, compared with supercapacitor 2, supercapacitor 1 has better specific capacitance, which is also unexpected because those skilled in the art generally believe that the same active material will have the same specific capacitance. In addition, supercapacitor 1 has a higher energy density than supercapacitor 2.

[0224] Example 11: Application in Sodium-Ion Batteries

[0225] Preparation of the negative electrode:

[0226] Preparation of the self-supporting hard carbon electrode film: The preparation method of the self-supporting hard carbon electrode film is the same as that of the self-supporting graphite electrode film in Example 1, except that the active material is replaced with hard carbon (such as Kuraray type-2).

[0227] Prepare a mixed aqueous solution of copper sulfate pentahydrate at a concentration of 200 g / L, glucose at a concentration of 20 g / L, and sulfuric acid at a concentration of 65 g / L as the electrolyte for copper plating on the surface of the negative electrode. Stick an insulating PE film on one side of the self-supporting hard carbon electrode film, immerse the hard carbon film and the copper foil together in the electrolyte, and connect them to a power supply to form a two-electrode system, where the self-supporting hard carbon electrode film is used as the cathode and the copper foil is used as the anode. Use direct current as the power supply, and use a current density of 2.5 A / dm 2 for electroplating at 0 °C for 100 seconds. Then take out the self-supporting hard carbon electrode film with the insulating PE film attached, remove the insulating PE film, and after drying, obtain the negative electrode 7 with an electroplated current collector thickness of 1 μm. Correspondingly, the self-supporting hard carbon electrode film is thermocompression laminated with a 9-μm carbon-coated copper foil (8-μm copper + 1-μm carbon) under the conditions of 180 °C and 500 kgf / cm 2 to obtain the negative electrode 8.

[0228] Preparation of the positive electrode:

[0229] Preparation of self-supporting Prussian blue electrode film: The preparation method of the self-supporting Prussian blue electrode film is the same as that of the self-supporting lithium iron phosphate electrode film in Example 7, except that the active material is replaced with Prussian blue (NaHCF).

[0230] In a glove box, aluminum chloride powder was added to the ionic liquid 1-ethyl-3-methylimidazolium chloride [EMIMCl] at a molar ratio of aluminum chloride: ionic liquid of 1.3:1, and after stirring and dissolving, an aluminum-plated electrolyte was obtained. One side of the self-supporting Prussian blue electrode film was pasted with an insulating PE film, and together with the aluminum foil, it was immersed in the electrolyte and connected to a power supply to form a two-electrode system, where the self-supporting Prussian blue electrode film served as the cathode and the aluminum foil served as the anode. Direct current was used as the power supply, and a current density of 2.5 A / dm 2 was applied for electrodeposition at 25 °C for 180 seconds. Then, the self-supporting Prussian blue electrode film with the insulating PE film attached was taken out, the insulating PE film was removed, and after drying, a positive electrode 3 with an electrodeposited current collector thickness of 2 μm was obtained. Correspondingly, the self-supporting Prussian blue electrode film was thermally laminated with a 16-μm carbon-coated aluminum foil (15-μm aluminum + 1-μm carbon) at 180 °C and 500 kgf / cm 2 to prepare a positive electrode 4.

[0231] Sodium-ion battery assembly: Referring to the assembly method of the lithium-ion battery in Example 7, the negative electrode 7 and the positive electrode 3, and the negative electrode 8 and the positive electrode 4 were respectively assembled into sodium-ion batteries 1 and 2 in an argon-filled glove box, where the electrolyte was a solution of 1 M NaPF 6 in DME (100% by volume).

[0232] Referring to the charge-discharge cycle test method of the sodium-ion battery in Example 7, the sodium-ion batteries 1 and 2 were tested. The test results are summarized in Table 12.

[0233] Table 12: Comparison of sodium-ion battery performance

[0234]

[0235] As can be seen from Table 12, sodium-ion battery 1 has significantly higher specific capacities of the positive electrode active material and the negative electrode active material than sodium-ion battery 2, which is unexpected because it is generally believed in the art that the same electrode active material will have the same specific capacity. In addition, sodium-ion battery 1 has a higher energy density than sodium-ion battery 2.

[0236] The above are only exemplary embodiments of the present invention. It should be noted here that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, improvements can still be made to the present invention, but these all fall within the protection scope of the present invention.

Claims

1. A method for preparing an electrode, comprising: (a) providing a self-supporting electrode film comprising a first side and a second side opposite to the first side, the second side comprising a to-be-deposited region on which a metal is deposited when in contact with an electrolyte to undergo an electrodeposition reaction; (b) providing an electrolyte containing a salt of the metal to be deposited; (c) contacting at least the area to be deposited on the second side of the self-supporting electrode film with the electrolyte, and performing an electrodeposition reaction in the area to be deposited, thereby depositing a current collector of the metal to be deposited on the second side, wherein the electrodeposition temperature is 0 to 70°C, preferably 0 to 30°C, more preferably 0 to 20°C, and more preferably 0 to 10°C.

2. The method according to claim 1, wherein step (a) further comprises providing an auxiliary conductor on at least a portion or all of a first region on a first side of the self-supporting electrode film, the first region being a corresponding region opposite to a region to be deposited on the second side, and the auxiliary conductor contacts the first region during electrodeposition.

3. The method according to claim 2, wherein the auxiliary conductor is selected from a metal foil such as a copper foil or an aluminum foil, and step (a) also optionally includes providing a protective layer on at least the first region of the first side of the self-supporting electrode film, wherein the protective layer is used to protect the first side from being deposited with a current collector during the electrodeposition process, and the method further includes removing the auxiliary conductor and the optional protective layer after the electrodeposition is completed.

4. The method according to claim 2, wherein the auxiliary electric conductor is selected from a conductive roller, the entirety of which or at least its surface is made of metal such as copper or aluminum. 5 . The method according to claim 1 , wherein the self-supporting electrode film is a cathode film, and the metal to be deposited is aluminum. 6 . The method according to claim 1 , wherein the self-supporting electrode film is a cathode film, and the metal to be deposited is copper.

7. The method according to any one of claims 1 to 6, wherein one or more of the following conditions are met: (i) the surface roughness of the self-supporting electrode film is 0.02-0.50 μm, for example 0.02-0.20 μm; (ii) the protective layer is made of one or more materials selected from polyimide (PI), polyethylene (PE), polypropylene (PP), and polytetrafluoroethylene (PTFE); (iii) the electrolyte is an aqueous system or a non-aqueous system and comprises: a solvent; a salt containing the metal to be deposited; and optionally one or more of a leveler, a brightener, a stabilizer, an acid or a base, Preferably, when the electrolyte is an aqueous system, the solvent comprises water and optionally further comprises an organic solvent miscible with water; When the electrolyte is a non-aqueous system, the electrolyte includes an organic solvent and / or an ionic liquid; Preferably, the organic solvent is selected from one or more of ethers such as tetrahydrofuran, aromatic hydrocarbons, and derivatives thereof; and / or the ionic liquid is selected from one or more of halogenated alkyl pyridines, halogenated alkyl imidazolines, or halogenated alkyl aryl ammonium salts; Preferably, when performing electrodeposition, the self-supporting electrode film is used as a cathode and a metal foil containing the metal to be deposited, for example, a metal foil of the metal to be deposited, is used as an anode.

8. The method according to any one of claims 1 to 7, wherein the process conditions during the electrodeposition of the current collector further include one or more of the following: the current is selected from any one of a DC constant current, a pulse, a square wave, a triangle wave, a sine wave, or a superposition thereof; the current density is 0.1-10 A / dm 2 ; the electrodeposition time is 30-1800 seconds; and the thickness of the electrodeposited current collector is 0.1-20 μm.

9. The method according to any one of claims 1 to 8, wherein one or more of the following are satisfied: (iv) step (a) further comprises washing the self-supporting electrode film with a solvent, and / or purging the self-supporting electrode film with a gas flow; (v) step (a) further comprises placing the self-supporting electrode film in a charged state; or (vi) Step (a) further comprises performing a surface treatment on the self-supporting electrode film using plasma.

10. An electrode prepared by the method according to any one of claims 1 to 9.

11. An energy storage device comprising the electrode according to claim 10.

12. The energy storage device according to claim 11, wherein any one of the following conditions is met: (vii) The energy storage device is a lithium ion secondary battery, and preferably, the 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 olivine structure lithium phosphate, preferably LiMn2O4, LiNiMnCoO2, 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 One or more of O2 and LiFePO4, Preferably, the negative electrode active material is selected from one or more of natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, silicon-based materials, tin-based materials, lithium titanate and metallic lithium, preferably one or more of graphite and silicon-based materials, more preferably one or more of graphite, silicon-carbon composites and silicon alloys; or (viii) The energy storage device is a sodium ion secondary battery. Preferably, the positive electrode active material is selected from one or more of layered transition metal oxides or Prussian blue analogs, preferably NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 One or more of O2, Na2FeP2O7, Na4Fe3(PO4)2(P2O7), Na3V2(PO4)3, NaFePO4 and NaMnFe(CN)6, Preferably, the negative electrode active material is selected from one or more of natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, silicon-based materials and tin-based materials, preferably one or more of graphite and silicon-based materials, more preferably one or more of graphite, silicon-carbon composites and silicon alloys; or (ix) The energy storage device is a supercapacitor, and preferably, the positive electrode active material is selected from one or more of metal oxides, conductive polymers and carbon materials, preferably one or more of MnO2, NiO, Co3O4, polyaniline, polypyrrole, activated carbon, graphene and biochar, Preferably, 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 and MnO2.

13. An electrode production system for carrying out the method according to any one of claims 1 to 9, comprising: A self-supporting electrode film providing module for providing a self-supporting electrode film, the self-supporting electrode film comprising a first side and a second side opposite to the first side, the second side comprising a to-be-deposited area on which a metal is deposited when in contact with an electrolyte for an electrodeposition reaction; an optional surface cleaning and treatment module, located upstream of the electrodeposition module, for cleaning and treating the surface of the self-supporting electrode film; An electrolyte supply module, used for providing an electrolyte for electrodeposition to the electrodeposition module; A temperature control module, used to control the temperature of the electrodeposition module to control the electrodeposition temperature to be 0 to 70°C, preferably 0 to 30°C, more preferably 0 to 20°C, more preferably 0 to 10°C; an electrodeposition module, located downstream of the self-supporting electrode film providing module and the electrolyte providing module, for depositing a current collector on a second side of the self-supporting electrode film; an optional cleaning and drying module, located downstream of the electrodeposition module, for cleaning and drying the prepared electrode; A transmission module, used to move the self-supporting electrode membrane between various modules of the electrode production system; and An optional collection and transport module is used to collect and transport the prepared electrodes.

14. The electrode production system according to claim 13 further includes an optional auxiliary conductor setting module, which is located downstream of the self-supporting electrode film providing module and the optional surface cleaning and treatment module and upstream of the electro-deposition module, and is used to set an auxiliary conductor on at least a part or all of the first area on the first side of the self-supporting electrode film, wherein the first area is a corresponding area opposite to the area to be deposited on the second side, and the auxiliary conductor contacts the first area during electro-deposition.

15. The electrode production system according to claim 14, further comprising: an optional protective layer setting module, located downstream of the self-supporting electrode film providing module and the optional auxiliary conductor setting module and upstream of the electrodeposition module, for setting a protective layer on at least the first region of the first side of the self-supporting electrode film, wherein the protective layer is used to protect the first side from being deposited with a current collector during the electrodeposition process; an optional separation module, located downstream of the electrodeposition module, for removing the optional auxiliary electrical conductor and the optional protective layer; an optional protective layer recycling module, located downstream of the optional separation module, for transferring the separated protective layer to the optional protective layer setting module for reuse; and An optional rolling module, the rolling module comprising a first part and an optional second part, wherein the first part is located upstream of the self-supporting electrode membrane providing module and is used to roll the self-supporting electrode membrane, and the optional second part is located downstream of the optional separation module and is used to roll the prepared electrode.

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