Metal organic precursor solution applied to composite current collector as well as preparation method and application of metal organic precursor solution

Abstract

The invention discloses a metal organic precursor solution as well as a preparation method and application thereof, and the metal organic precursor solution comprises the following components in percentage by mass: 10%-30% of a metal organic precursor, 15%-40% of a binder and the balance of a solvent. After the prepared metal organic precursor solution is sprayed on a base membrane, functional groups in the binder and the surface of the base membrane are subjected to physical and chemical effects, the metal organic precursor is decomposed in the thermocuring and sintering processes to form metal nanoparticles, and the metal nanoparticles and the binder cooperate to construct an organic-inorganic gradient interface; according to the invention, the composition diversification and structure gradient synergism is realized, by compounding binders with different proportions and mechanisms, the method adapts to different PET, PP and other polymer base membrane characteristics, an interface layer with transition gradient and high reaction activity is formed on the surface of the base membrane, the adhesion strength and long-term stability between a metal coating and the base membrane can be remarkably improved, and the service life of the metal coating is prolonged. And meanwhile, an optimized low-temperature sintering process also ensures the friendliness to the heat-sensitive base membrane.

Description

Technical Field

[0001] This invention belongs to the field of composite current collector technology, specifically relating to a metal-organic precursor solution for composite current collectors, its preparation method, and its application. Background Technology

[0002] Current collectors are an indispensable electrode material in lithium-ion batteries, playing a crucial role in carrying active materials and collecting and conducting microcurrents. Composite current collectors have a "sandwich" structure, with an inner polymer layer and conductive metal layers on both sides. Currently, in industrially mass-produced composite current collectors, composite aluminum foil typically uses PET as the base film, and then aluminum layers are deposited on both sides of the base film. Although PET composite aluminum foil can improve flexibility, the interfacial bonding between the aluminum layer and the PET film is weak, making it prone to dissolution, swelling, or reaction in the electrolyte. This can lead to the metal layer detaching during use, affecting conductivity.

[0003] To address the technical challenge of weak adhesion between the metal layer and the substrate film, current industrially used physical or chemical treatment methods have significant limitations. For example, while corona treatment or plasma activation can temporarily increase the surface tension of the substrate film, the effect diminishes over time and requires expensive equipment. Directly spraying adhesives can lead to uneven coating or gas release in a vacuum environment due to residual organic solvents and high volume shrinkage stress, thus contaminating the coating environment. Furthermore, although nanoimprinting or laser etching can enhance mechanical interlocking by constructing micro- and nano-structures, they require highly precise equipment and may damage the integrity of the substrate film.

[0004] Therefore, this invention proposes a metal-organic precursor solution, its preparation method, and its application. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a metal-organic precursor solution for use in composite current collectors, its preparation method, and its application.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the metal-organic precursor solution applied to the composite current collector comprises the following components by mass percentage: 10%~30% organometallic precursor, 15%~40% binder, balance is solvent; The metal-organic precursor is an aluminum precursor or a copper precursor. The binder comprises a silane coupling agent, a resin, and cellulose, wherein the mass ratio of the silane coupling agent, the resin, and the cellulose is 4~16:2~10:1.

[0009] Furthermore, the solvent is a mixture of deionized water and an organic solvent, wherein the organic solvent includes at least one of ethanol, isopropanol, or ethylene glycol butyl ether.

[0010] Furthermore, the aluminum precursor includes aluminum oxide or an organoaluminum complex with the general formula Al(OR¹)(OR²)(OR³), wherein R¹, R², and R³ are independently selected from C1-C5 alkyl, carboxyl, and aromatic groups; The copper precursor includes copper neodecanoate, copper octoate, or copper nanoparticles.

[0011] Furthermore, the silane coupling agent is a compound of γ-aminopropyltriethoxysilane and phenyltrimethoxysilane in a mass ratio of 1.5 to 3:1; The resin is a water-based epoxy resin, polyester resin, or acrylic resin. The cellulose includes at least one of hydroxyethyl cellulose, hydroxypropyl methylcellulose, and methylcellulose.

[0012] Furthermore, in the organometallic precursor solution, the weight percentage of resin is 5-15%, and the weight percentage of cellulose is 1-5%.

[0013] This invention also proposes a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: S1: Mix the silane coupling agent with half of the solvent, adjust the pH to 4-5, and stir to fully hydrolyze it to obtain a hydrolyzed solution; S2: Mix the organometallic precursor with the other half of the solvent, add resin and cellulose, and shear at high speed to obtain a metal precursor dispersion. S3: Add the hydrolysis solution to the metal precursor dispersion and stir until homogeneous. Filter the solution through a sieve to obtain the metal-organic precursor solution for use in composite current collectors.

[0014] Furthermore, the solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3.

[0015] The present invention also proposes a current collector comprising a base film, a coating attached to the base film, and a metal layer on the surface of the coating. The coating is formed by spraying the metal-organic precursor solution of any one of claims 1 to 5, which is applied to the composite current collector, onto the surface of the base film and then curing it.

[0016] Furthermore, the preparation method of this current collector includes the following steps: S1: A wet-coated base film is obtained by spraying a metal-organic precursor solution onto the pretreated base film surface; S2: Place the wet-coated base film in an oven at 80~100℃ for 1~2 minutes to heat cure, and then sinter it at 130~200℃ for 1~5 minutes under an inert atmosphere to obtain a sintered base film; S3: The sintered base film is then sent into a vacuum coating equipment to deposit a surface metal layer to obtain a current collector.

[0017] Furthermore, the bonding force between the base film and the metal layer is not less than 1.5 N / mm.

[0018] Beneficial effects of this invention: When the metal-organic precursor solution prepared by this invention is sprayed onto the base film, the functional groups in the binder interact with the surface of the base film through physicochemical reactions. During the thermosetting and sintering process, the metal-organic precursor decomposes to form metal nanoparticles, which synergistically construct an organic-inorganic gradient interface with the binder. This alleviates the interfacial stress caused by the difference in thermal expansion coefficients and achieves a lasting bond through strong forces such as covalent bonds and coordination bonds.

[0019] This invention achieves a synergy between compositional diversification and structural gradient. By compounding binders with different ratios and mechanisms, it adapts to the characteristics of different polymer base films such as PET and PP, forming an interface layer with a transitional gradient and high reactivity on the base film surface. This significantly improves the adhesion strength and long-term stability between the metal coating and the base film. At the same time, the optimized low-temperature sintering process also ensures friendliness to heat-sensitive base films.

[0020] In this invention, the binder system and the metal precursor form an organic-inorganic gradient interface during sintering. The silane coupling agent binds to the base film surface through Si-OC covalent bonds, and at the other end, it forms coordination bonds or hydrogen bonds with the metal precursor or subsequent metal layer through functional groups such as -NH2. The metal precursor decomposes into metal nanoparticles during low-temperature sintering. These particles are uniformly dispersed in the binder network and form physical-chemical crosslinks with resin and cellulose through surface functional groups, enhancing interfacial toughness and adhesion, while promoting uniform coating distribution and reducing stress concentration. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] All raw materials used in this invention are commercially available in the field.

[0025] Preparation Example 1 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 12 parts of γ-aminopropyltriethoxysilane, 5 parts of phenyltrimethoxysilane and 24 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 hour to obtain a hydrolyzed solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 25 parts of aluminum sec-butoxide with 24 parts of solvent, add 8 parts of water-based acrylic resin and 2 parts of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0026] Preparation Example 2 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 15 parts of γ-aminopropyltriethoxysilane, 8 parts of phenyltrimethoxysilane and 22 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 hour to obtain a hydrolysis solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 20 parts of aluminum sec-butoxide with 23 parts of solvent, add 10 parts of water-based acrylic resin and 2 parts of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0027] Preparation Example 3 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 20 parts of γ-aminopropyltriethoxysilane, 10 parts of phenyltrimethoxysilane and 25 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 hour to obtain a hydrolyzed solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 25 parts of aluminum sec-butoxide with 25 parts of solvent, add 15 parts of water-based acrylic resin and 3 parts of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0028] Comparative Preparation Example 1 The difference between this comparative preparation example and preparation example 1 is that no silane coupling agent is added, while the rest of the preparation process is the same as that of preparation example 1, resulting in the organometallic precursor solution of this comparative preparation example 1.

[0029] Comparative Preparation Example 2 The difference between this comparative preparation example and preparation example 1 is that no metal precursor is added, while the rest of the preparation process is the same as that of preparation example 1, resulting in the metal-organic precursor solution of this comparative preparation example 2.

[0030] Comparative preparation example 3 The difference between this comparative preparation example and preparation example 1 is that no resin is added, but the rest of the preparation process is the same as that of preparation example 1, resulting in the metal-organic precursor solution of this comparative preparation example 3.

[0031] Comparative preparation example 4 The difference between this comparative preparation example and preparation example 1 is that cellulose is not added, but the rest of the preparation process is the same as that of preparation example 1, resulting in the metal-organic precursor solution of this comparative preparation example 4.

[0032] Preparation Example 4 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 10 parts of γ-aminopropyltriethoxysilane, 6 parts of phenyltrimethoxysilane and 22 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 hour to obtain a hydrolysis solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 28 parts of copper neodecanoate with 23 parts of solvent, add 10 parts of water-based acrylic resin and 1 part of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0033] Preparation Example 5 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 18 parts of γ-aminopropyltriethoxysilane, 7 parts of phenyltrimethoxysilane and 20 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 h to obtain a hydrolysis solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 25 parts of copper neodecanoate with 23 parts of solvent, add 8 parts of water-based acrylic resin and 2 parts of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0034] Preparation Example 6 This preparation example provides a method for preparing a metal-organic precursor solution for use in composite current collectors, comprising the following steps: 1) Mix 25 parts of γ-aminopropyltriethoxysilane, 10 parts of phenyltrimethoxysilane and 26 parts of solvent, adjust the pH to 4.5 with dilute acetic acid, and stir at 60°C for 1 hour to obtain a hydrolysate solution. The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:3. 2) Mix 30 parts of copper neodecanoate with 28 parts of solvent, add 12 parts of water-based acrylic resin and 3 parts of hydroxyethyl cellulose, and shear at 3000 rpm for 30 min to obtain a metal precursor dispersion. 3) Slowly add the hydrolysate from step 1) to the metal precursor dispersion from step 2), stir at 500 rpm for 2 hours, and filter through a 100-mesh sieve to obtain the organometallic precursor solution.

[0035] Comparative preparation example 5 The difference between this comparative preparation example and preparation example 4 is that no silane coupling agent is added, while the rest of the preparation process is the same as that of preparation example 4, resulting in the organometallic precursor solution of this comparative preparation example 5.

[0036] Comparative preparation example 6 The difference between this comparative preparation example and preparation example 4 is that no metal precursor is added, while the rest of the preparation process is the same as that of preparation example 4, resulting in the metal-organic precursor solution of this comparative preparation example 6.

[0037] Comparative preparation example 7 The difference between this comparative preparation example and preparation example 4 is that no resin is added, but the rest of the preparation process is the same as that of preparation example 4, resulting in the metal-organic precursor solution of this comparative preparation example 7.

[0038] Comparative Preparation Example 8 The difference between this comparative preparation example and preparation example 4 is that cellulose is not added, but the rest of the preparation process is the same as that of preparation example 4, resulting in the organometallic precursor solution of this comparative preparation example 8.

[0039] Example 1 This embodiment provides an application of a metal-organic precursor solution in the preparation of current collectors, including the following steps: 1) After corona treatment, a 12μm thick PET base film was ultrasonically sprayed with a metal-organic precursor solution at 25℃ and 50% relative humidity, with the droplet diameter controlled at 20μm and the wet film thickness at 5μm to obtain a wet-coated base film. 2) Place the wet-coated base film in a drying oven at 100℃ for 90 seconds to pre-cur it, and then sinter it in nitrogen at 180℃ for 3 minutes to obtain the sintered base film; 3) The sintered base film is fed into a vacuum coating equipment, and a 2μm thick aluminum layer is deposited by magnetron sputtering or vapor deposition to obtain the current collector sample.

[0040] The organometallic precursor solutions were obtained from Preparation Examples 1-3 and Comparative Preparation Examples 1-4, respectively, resulting in current collector samples 1-3 and 11-14.

[0041] Example 2 This embodiment provides an application of a metal-organic precursor solution in the preparation of current collectors, including the following steps: 1) After treating a 10μm thick PP base film with nitrogen plasma, a metal-organic precursor solution was slit-coated to obtain a wet-coated base film with a wet film thickness of 3μm. 2) Place the wet-coated base film in a 90℃ oven for 2 minutes to pre-cur it, and then sinter it in nitrogen at 150℃ for 4 minutes to obtain the sintered base film; 3) The sintered base film is fed into a vacuum coating equipment, and a 1.5 μm thick copper layer is deposited by magnetron sputtering to obtain the current collector sample.

[0042] The organometallic precursor solutions were obtained from Preparation Examples 4-6 and Comparative Preparation Examples 5-8, respectively, resulting in current collector samples 4-6 and 15-18.

[0043] Comparative Example 1 Comparative Example 1 provides a method for preparing a composite current collector, comprising the following steps: After corona treatment, a 12μm thick PET base film was coated with acrylic adhesive, and a 2μm thick aluminum layer was deposited by magnetron sputtering or vapor deposition to obtain composite current collector sample 19.

[0044] The adhesion of the current collector samples prepared in Examples 1-2 and Comparative Example 1 was tested using the cross-cut adhesion test, and the results are shown in Table 1.

[0045] Table 1

[0046] As can be seen from Table 1, the composite current collector prepared by this invention has better bonding force. This is because the amino group provided by the silane coupling agent can form hydrogen bonds or covalent bonds with the carbonyl / carboxyl groups on the surface of the PET base film, react with the hydroxyl groups on the surface of the PP base film, and form coordination bonds with metals such as copper and aluminum, thereby constructing a strong polar interface. The benzene ring structure provided by the silane coupling agent provides hydrophobicity and flexibility, effectively reducing the internal stress of the interface layer and enhancing the physical compatibility between the interface layer and the base film surface. After hydrolysis and condensation, the silane coupling agent forms a hybrid network on the surface of the base film, and further forms a covalent network of base film-silane-resin with functional groups such as carboxyl and hydroxyl groups in the resin, realizing molecular-level connection from the base film to the resin. At the same time, the resin acts as a stress buffer layer, absorbing the shear stress caused by the mismatch of the thermal expansion coefficients between the interface layer and the base film surface. The silane layer ensures that this stress can be effectively transferred from the resin layer and dispersed into the base film body, preventing stress concentration that leads to delamination. The cellulose polymer chains encapsulate and stably disperse the initial aggregates of silane and resin and the metal precursor through physical entanglement and hydrogen bonding, preventing phase separation or precipitation before storage and spraying, ensuring the homogeneity and stability of the precursor solution, and thinning after shearing, providing a certain degree of pseudoplasticity. This makes the viscosity of the solution decrease under the spraying shear force, easy to atomize, and the viscosity recovers rapidly after reaching the base film surface, preventing solution sagging and excessive penetration, thereby accurately controlling the wet film thickness and morphology. In the subsequent heat treatment process, it also ensures the flatness of the current collector sample surface.

[0047] In the aluminum precursor system, corresponding to current collector samples 1-3 and 11-14, as shown in Table 1, the current collector samples prepared by this invention exhibit strong bonding between the metal layer and the base film, a low probability of metal layer detachment during use, low sheet resistance, good electrical conductivity, good resistance to damp heat, and are not easily dissolved, swollen, or reacted in the electrolyte. In particular, when the mass ratio of silane coupling agent, resin, and cellulose is 17:8:2, the bonding between the metal layer and the base film in the current collector sample is strongest. At this point, the amount of silane coupling agent is sufficient to cover the interfacial active sites between the base film and the metal layer, the resin can completely encapsulate the silane coupling agent molecules and fill the interfacial micro-gaps, and the cellulose avoids interfacial defects caused by excessive stacking of molecular chains, ultimately achieving the optimal value of interlayer bonding force, which can serve as a qualified lithium-ion battery electrode material. When the metal-organic precursor solution component is missing, the bonding force between the metal layer and the base film in the current collector sample drops to half that of this invention, and the resistance to damp heat is poor, failing to meet the requirements of the electrode material.

[0048] In the copper precursor system, corresponding to current collector samples 4-6 and 15-18, as shown in Table 1, the current collector samples prepared by this invention have strong bonding between the metal layer and the base film, and the possibility of metal layer detachment during use is low, with low sheet resistance. In particular, when the mass ratio of silane coupling agent, resin and cellulose is 16:10:1, the bonding between the metal layer and the base film in the current collector sample is the strongest.

[0049] As can be seen from Comparative Example 1, traditional acrylic adhesives have a bonding strength of only 0.7 N / mm, a sheet resistance of >2.0 Ω / sq, and poor resistance to damp heat, which cannot meet the requirements of electrode materials.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A metal-organic precursor solution for use in composite current collectors, characterized in that: The organometallic precursor solution comprises the following components by mass percentage: 10%~30% organometallic precursor, 15%~40% binder, balance is solvent; The metal-organic precursor is an aluminum precursor or a copper precursor. The binder comprises a silane coupling agent, a resin, and cellulose, wherein the mass ratio of the silane coupling agent, the resin, and the cellulose is 4~16:2~10:

1.

2. The organometallic precursor solution for use in composite current collectors as described in claim 1, characterized in that: The solvent is a mixture of deionized water and an organic solvent, wherein the organic solvent includes at least one of ethanol, isopropanol, or ethylene glycol butyl ether.

3. The organometallic precursor solution for use in composite current collectors as described in claim 1, characterized in that: The aluminum precursor includes aluminum oxide or an organoaluminum complex with the general formula Al(OR¹)(OR²)(OR³), wherein R¹, R², and R³ are independently selected from C1-C5 alkyl, carboxyl, and aromatic groups; The copper precursor includes copper neodecanoate, copper octoate, or copper nanoparticles.

4. The organometallic precursor solution for use in composite current collectors as described in claim 1, characterized in that: The silane coupling agent is a compound of γ-aminopropyltriethoxysilane and phenyltrimethoxysilane in a mass ratio of 1.5 to 3:

1. The resin is a water-based epoxy resin, polyester resin, or acrylic resin. The cellulose includes at least one of hydroxyethyl cellulose, hydroxypropyl methylcellulose, and methylcellulose.

5. The organometallic precursor solution for use in composite current collectors as described in claim 1, characterized in that: In the metal-organic precursor solution, the weight percentage of resin is 5-15%, and the weight percentage of cellulose is 1-5%.

6. The method for preparing the metal-organic precursor solution for use in composite current collectors as described in any one of claims 1 to 5, characterized in that: Includes the following steps: S1: Mix the silane coupling agent with half of the solvent, adjust the pH to 4-5, and stir to fully hydrolyze it to obtain a hydrolyzed solution; S2: Mix the organometallic precursor with the other half of the solvent, add resin and cellulose, and shear at high speed to obtain a metal precursor dispersion. S3: Add the hydrolysis solution to the metal precursor dispersion and stir until homogeneous. Filter the solution through a sieve to obtain the metal-organic precursor solution for use in composite current collectors.

7. The method for preparing the metal-organic precursor solution for use in composite current collectors as described in claim 6, characterized in that: The solvent is a mixture of deionized water and ethanol in a mass ratio of 1:

3.

8. A current collector comprising a base film, a coating adhered to the base film, and a metal layer on the surface of the coating, characterized in that: The coating is formed by spraying the metal-organic precursor solution of any one of claims 1 to 5 onto the surface of the base film and curing it.

9. The method for preparing the current collector as described in claim 8, characterized in that: Includes the following steps, S1: A wet-coated base film is obtained by spraying a metal-organic precursor solution onto the pretreated base film surface; S2: Place the wet-coated base film in an oven at 80~100℃ for 1~2 minutes to heat cure, and then sinter it at 130~200℃ for 1~5 minutes under an inert atmosphere to obtain a sintered base film; S3: The sintered base film is then sent into a vacuum coating equipment to deposit a surface metal layer to obtain a current collector.

10. The current collector as described in claim 8, characterized in that: The bonding force between the base film and the metal layer is not less than 1.5 N / mm.

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