CN117276552B - Multilayer structure current collector and preparation method thereof - Google Patents
Multilayer structure current collector and preparation method thereof Download PDFInfo
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 30
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/661—Metal or alloys, e.g. alloy coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/661—Metal or alloys, e.g. alloy coatings
- H01M4/662—Alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/668—Composites of electroconductive material and synthetic resins
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
The invention discloses a multilayer structure current collector and a preparation method thereof, wherein the multilayer structure current collector comprises the following components: a base layer having two surfaces in the thickness direction; the conductive layer is arranged on at least one surface of the matrix layer and comprises at least one group of unit layers with a first conductive filler layer, a metal layer and a second conductive filler layer which are sequentially compounded as a circulating matrix; wherein the first conductive filler layer and/or the second conductive filler layer comprises uniformly or unevenly distributed agglomerates formed on the surface layer to increase the adhesion capability of the metal layer. The current collector and the preparation method can quickly form a coating bonding interface with certain roughness and provide good corrosion resistance.
Description
Technical Field
The invention relates to the technical field of current collectors, in particular to a multilayer structure current collector and a preparation method thereof.
Background
Current collectors refer to structures or parts that collect current, typically metallic foil materials, such as copper foil, aluminum foil; in order to further increase the energy density, a composite current collector is further introduced in the prior art; for the positive current collector, the active material is required to be coated finally, and the active material of the battery can corrode the metal layer during the use process, so that the conductivity is affected.
In the prior art, a scheme of arranging a protective layer on the surface of the conductive layer is adopted, and the protective layer can select related acid and alkali corrosion resistant metal elements and play a role in protection through physical, chemical and other deposition modes.
However, although the bonding to the film is improved to some extent by the primer layer in the above manner, the processing cost is relatively high, and thus further improvement is required.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a multilayer structure current collector and a method for manufacturing the same, which can rapidly form a coating bonding interface having a certain roughness and provide good corrosion resistance.
The technical scheme of the invention is as follows:
A multi-layered structure current collector comprising:
a base layer having two surfaces in the thickness direction;
The conductive layer is arranged on at least one surface of the matrix layer and comprises at least one group of unit layers with a first conductive filler layer, a metal layer and a second conductive filler layer which are sequentially compounded as a circulating matrix;
wherein the first conductive filler layer and/or the second conductive filler layer comprises uniformly or unevenly distributed agglomerates formed on the surface layer to increase the adhesion capability of the metal layer.
Further, the surface roughness of the first conductive filler layer and/or the second conductive filler layer is 20% -50% of the thickness of the corresponding coating.
The preparation method of the multilayer structure current collector comprises the following steps:
S1, providing a substrate layer capable of being wound;
s2, providing a first conductive filler and a first aggregation regulator to form a first conductive filler layer on the outer surface of the matrix layer;
S3, forming a metal layer on the outer surface of the first conductive filler layer;
s4, providing a second conductive filler and a second aggregation regulator to form a second conductive filler layer on the outer surface of the matrix layer;
s5, selecting the circulation times according to actual needs to obtain the multilayer structure current collector with a certain thickness.
Further, the thickness of the matrix layer is 1-20 mu m; the substrate layer is a metal foil; or, a composite current collector; or, a polymer film.
Further, the conductive filler in the first conductive filler layer and/or the second conductive filler layer comprises nanoscale chromium, nickel, metal alloy thereof and carbon-based filler or combination thereof, and the particle size is selected to be 50-200nm.
Further, the solid content of the conductive filler is 10-30%.
Further, the first conductive filler layer and the second conductive filler layer also comprise a binder, and the mass ratio of the binder to the conductive filler is (0.02-0.05): 1; the binder is at least one of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose and SBR.
Further, the first and/or second agglomeration modifiers include a dispersant and a solvent at a lower threshold level, and the solvent is volatile to form a gas during drying.
Further, the lower threshold content is set to be such that when the conductive filler is agglomerated in the solvent, the particle size distribution thereof is shifted by 5 to 10% due to the agglomeration.
Further, the consumption of the dispersing agent is 0.5-5% of the mass of the conductive filler.
Further, the drying condition is that the temperature of the first section of oven is 65-75 ℃, the time is 20-30 seconds, the temperature of the second section of oven is 75-85 ℃, and the time is 15-30 seconds; the temperature of the third section of oven is 65-75 ℃ and the time is 5-20 seconds; the thickness of the first conductive filler layer and the second conductive filler layer is 0.1-20 μm.
Further, the thickness of the metal layer is controlled to be 0.1-1 mu m.
Further, the first conductive filler and/or the second conductive filler comprise nano graphene oxide and nano conductive filler, and the nano graphene oxide and the nano conductive filler are dispersed in a solvent to obtain conductive filler slurry; wherein, the concentration of the graphene oxide is controlled to be 0.5-1g/L, the solid content of the conductive filler is controlled to be 10% -30%, and the coating is carried out after the conductive filler is fully dispersed.
Further, the width of the graphene oxide sheet is 0.5-3 mu m, and the particle size of the nano conductive filler is 0.1-0.5 mu m.
Further, the first agglomeration regulator and/or the second agglomeration regulator are/is set as an acidic regulator, the pH is controlled to be 1.5-2, the mass ratio of the additive amount to the conductive filler slurry is (0.08-0.1): 1, and the conductive filler slurry is coated by adopting a spraying or coating mode and is further heated and dried.
Further, the metal layer is made of aluminum or an alloy material containing aluminum.
Further, the matrix layer is a metal foil containing aluminum and aluminum copper alloy; or a composite current collector, wherein the conductive material of the composite current collector is aluminum or copper-aluminum alloy material.
The invention has the beneficial effects that: the anti-corrosion nickel, chromium and carbon-based conductive filler can protect aluminum, copper and the like in the current collector, and further form agglomerates in the conductive filler layer and cooperate with a gas atmosphere formed by a volatile solvent to promote the agglomerates to be dispersed and aggregated on the surface layer of the coating, so that the distribution of large-particle-size particles on the surface of the coating is increased to a certain extent, the roughness of the surface is relatively high, and the anti-corrosion nickel, chromium and carbon-based conductive filler is easy to combine with other coatings; the agglomerates are further arranged to be GO and are matched with an acidic agglomeration regulator to further and more conveniently regulate the roughness of the formed coating.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments.
A multi-layered structure current collector comprising:
The substrate layer can be a metal foil material such as aluminum foil, aluminum copper alloy and the like which react with acid, or a polymer film layer such as PP, PET, PI and the like; or a composite current collector, wherein the conductive material of the composite current collector is aluminum or copper-aluminum alloy material;
The conductive layer is arranged on at least one surface of the matrix layer and comprises at least one group of unit layers with a first conductive filler layer, a metal layer and a second conductive filler layer which are sequentially compounded as a circulating matrix;
Wherein the first conductive filler layer and the second conductive filler layer comprise uniformly or unevenly distributed aggregates formed on the surface layer so as to increase the adhesion capability of the metal layer; the diameter of the formed agglomerate is adjusted and selected according to the particle diameter and the property of the conductive filler and the thickness of the coating, for example, the average diameter of the agglomerate can be 0.5-5 mu m, the average diameter of the agglomerate can be 5-10 mu m, and the like, and the surface roughness of the formed coating is about 20-50% of the thickness of the corresponding coating.
The preparation method of the current collector comprises the following steps:
S1, providing a substrate layer capable of being wound;
s2, providing a first conductive filler and a first aggregation regulator to form a first conductive filler layer on the outer surface of the substrate layer, wherein the outer surface refers to the side which is opposite to the outer side of the substrate layer, and the same applies below;
S3, forming a metal layer on the outer surface of the first conductive filler layer;
s4, providing a second conductive filler and a second aggregation regulator to form a second conductive filler layer on the outer surface of the matrix layer;
s5, selecting the circulation times according to actual needs to obtain a current collector structure with a certain thickness.
Wherein,
For the substrate layer is aluminum-containing metal foil, the thickness of the substrate layer can be 8-15 mu m according to actual requirements; the thickness of the matrix layer is 3-15 mu m for the polymer layer or the composite current collector; of course, other thicknesses are also within the scope of the present application.
The conductive filler in the first conductive filler layer and the second conductive filler layer comprises nanoscale chromium, nickel, metal alloy thereof and carbon-based filler or a combination thereof, and the particle size is selected to be 50-200nm, so that the conductive filler has relatively good corrosion resistance and can protect metal aluminum in the current collector to a certain extent; after sieving, conductive filler particles with relatively concentrated particle sizes are selected to be distributed and dispersed in a solvent, the solid content (mass) is controlled to be 10-30%, the conductive fillers in the first conductive filler layer and the second conductive filler layer also comprise a binder, and the mass ratio of the binder to the conductive filler is (0.02-0.05): 1, and the conductive filler is sheared and dispersed at high speed; the binder is at least one of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose and SBR.
The first agglomeration regulator and the second agglomeration regulator comprise a dispersant and a solvent with lower threshold content, the solvent can be deionized water, and of course, the solvent is preferably selected from solvents with lower boiling point, such as ethanol, acetone and the like, and can be dried in a vacuum environment, so that the solvent is more volatile to form gas in the drying process, on one hand, the coating can be provided with a certain hole after being solidified, and on the other hand, a small amount of agglomerated conductive particles are further pushed to move towards the surface of the coating, so that the distribution of large-particle-size particles on the surface layer of the coating is uneven, and the surface roughness is increased to a certain extent.
The lower threshold value is calibrated by setting a small amount of agglomeration of the conductive filler in a solvent, determining the offset of the particle size distribution due to the agglomeration by a particle size analyzer, wherein the offset of the agglomeration is preferably 5% -10%, and the adding amount of the dispersing agent is defined as the lower threshold value content so as to form a suspension of a small amount of agglomerated particles in the formed conductive filler layer solution. The consumption of the dispersing agent is 0.5% -5% of the mass of the conductive filler, and the dispersing agent selects the existing products such as Disperbyk103, disperbyk106, solsperse3000, solsperse13940, solsperse17000 and the like according to actual requirements.
Coating the upper dispersion liquid on the surface of the substrate layer, and drying, wherein the coating mode can be a blade coating mode, a coating machine coating mode, a screen printing mode or a spraying mode; during drying, the temperature of the first section of oven is 65-75 ℃, the time is 20-30 seconds, the temperature of the second section of oven is 75-85 ℃, and the time is 15-30 seconds; the temperature of the third section of oven is 65-75 ℃ and the time is 5-20 seconds; the thickness of the first conductive filler layer and the second conductive filler layer is about 0.5-20 μm.
The metal layer can be formed by vapor deposition (such as evaporation or sputtering) or water electroplating, and the thickness is controlled to be about 0.1-1 μm; because the surface of the first/second conductive filler layer has relatively larger particle diameter particles to be deposited, the surface of the first/second conductive filler layer has more gaps, molecules of the subsequent metal layer are easy to deposit in the gaps of the first/second conductive filler layer, and the effect of the metal layer and the conductive filler layer is increased.
In addition, the application further discloses a preparation method of the current collector with controllable aggregate formation regulation, which comprises the following steps:
the main differences are that:
In the steps S2 and S4, the conductive filler layer comprises nano graphene oxide (the particle size of the graphene oxide is 0.5-3 mu m) and nano conductive filler, wherein the conductive filler can be carbon-based conductive filler such as conductive graphite, conductive carbon black or metal conductive filler, or nano metal powder, and the particle size is 0.1-0.5 mu m; the concentration of GO is controlled to be 0.5-1g/L, the solid content of the conductive filler is controlled to be 10% -30%, and after full dispersion, the conductive filler is further homogenized or ultrasonically coated after being sheared and stirred at high speed;
the first/second agglomeration regulator is acid regulator such as sulfuric acid or hydrochloric acid solution, with pH of 1.5-2, the mass ratio of the additive amount to the conductive filler slurry is (0.08-0.1): 1, and the first/second agglomeration regulator is coated into the conductive filler slurry by spraying or coating, and further heated and dried (drying conditions are the same as above); at this time, in the mixing process of the agglomeration regulator and the conductive filler layer slurry, the pH of the system gradually becomes acidic, and the GO can generate agglomeration under the acidic condition, especially the surface layer preferentially reaches the agglomeration pH of the GO, and a small amount of conductive filler is wrapped, so that a core-shell structure with relatively compact internal filling is formed, the subsequent further processing (the texture is relatively compact, the strength is higher, the agglomeration is not easy to collapse due to extrusion) is facilitated, the particle size and the content of the formed agglomeration can be dynamically adjusted through the acid-base regulator and the GO content, and the roughness of the surface can be further controlled.
For the metal layer or the current collector interface is made of aluminum-containing materials, such as aluminum or copper-aluminum alloy materials, the aluminum-aluminum alloy material is easy to react with aluminum molecules in an acidic atmosphere, so that slight corrosion is generated, and the interface binding force is increased; similarly, the hydrogen produced also causes voids in the corresponding coating and enriches the surface layer with agglomerates of relatively large particle size.
Example 1
S1, providing a substrate layer capable of being wound, wherein the substrate layer is made of 12 mu m aluminum foil;
S2, providing a first conductive filler and a first agglomeration regulator, wherein the first conductive filler is nickel powder with the particle size of 100nm, the nickel powder is dispersed in ethanol at room temperature, polyvinylidene fluoride with the mass of 2% of the nickel powder is added into the solution, the solid content of the first conductive nickel powder is controlled to be 12%, the first agglomeration regulator is dispersant Disperbyk103 which is added into the ethanol in advance, the dosage is controlled to be 0.8%, a suspension is prepared after the dispersion is fully stirred, a small amount of agglomerated nickel powder (the agglomeration amount is about 8%) is formed in the suspension, the coating operation is immediately carried out, the coating thickness is about 5 mu m, and the surface roughness Ra is measured to be about 2.4 mu m after the drying;
s3, forming a metal layer on the outer surface of the first conductive filler layer, wherein the metal layer is an aluminum layer with the thickness of 0.2 mu m, and sputtering;
s4, providing a second conductive filler and a second aggregation regulator to form a second conductive filler layer on the outer surface of the matrix layer, wherein the second conductive filler and the second aggregation regulator are the same, and coating and drying to obtain the surface three-layer current collector structure.
Example two
S1, providing a substrate layer capable of being wound, wherein the substrate layer is an 8 mu mPP film;
S2, providing a first conductive filler and a first agglomeration regulator, wherein the first conductive filler is 80nm nickel powder, (ultrasonic) is dispersed in ethanol, SBR (styrene butadiene rubber) with the mass of 5% of aluminum powder is added into the solution, the solid content of the first conductive nickel powder is controlled to be 20%, the first agglomeration regulator is dispersant byk106 which is added into the ethanol in advance, the dosage is controlled to be 1.5%, a suspension is prepared after the dispersion is fully stirred, a small amount of agglomerated nickel powder (the agglomeration amount is about 5%) is formed, coating operation is immediately carried out, the coating thickness is about 10 mu m, and the surface roughness Ra is measured to be about 4.5 mu m after drying;
S3, forming a metal layer on the outer surface of the first conductive filler layer, wherein the metal layer is an aluminum layer with the thickness of 0.4 mu m, and performing vapor deposition;
S4, providing a second conductive filler and a second aggregation regulator, wherein the second conductive filler is the same as the first aggregation regulator in the first embodiment, and coating and drying to obtain the current collector structure with three layers on the surface.
Example III
S1, providing a substrate layer capable of being wound, wherein the substrate layer is a composite current collector with a 10 mu mPP substrate, and two sides of the composite current collector comprise aluminum layers with the thickness of 1 mu m respectively;
s2, providing a first conductive filler and a first agglomeration regulator, wherein the first conductive filler is 150nm chromium powder, dispersing the first conductive filler in acetone, adding polyvinylidene fluoride accounting for 4% of the mass of aluminum powder into the solution, controlling the solid content of the first conductive nickel powder to be 25%, controlling the dosage to be 3% by adding a dispersing agent Solsperse3000 into ethanol in advance into the first agglomeration regulator, fully stirring and dispersing to obtain a suspension, forming a small amount of agglomerated chromium powder (the agglomeration amount is about 6%), immediately performing coating operation, coating thickness is about 12 mu m, and measuring surface roughness Ra to be about 5 mu m after drying;
S3, forming a metal layer on the outer surface of the first conductive filler layer, wherein the metal layer is an aluminum layer with the thickness of 0.8 mu m, and performing vapor deposition;
S4, providing a second conductive filler and a second agglomeration regulator, wherein the second conductive filler comprises graphene oxide with the diameter of 1.5 mu m and conductive carbon black with the diameter of 0.3 mu m, the concentration of GO is controlled to be 0.5g/L, the solid content of the system is controlled to be 25%, the second agglomeration regulator is a dilute sulfuric acid solution, the pH is 2, the content is 8% of the mass of the conductive filler slurry, and the second conductive filler is sprayed towards the surface of the slurry in an atomizing way; the thickness of the coating was about 20 μm, and after drying, the surface roughness was measured to be 6.0 μm, to obtain a composite current collector having a surface three-layer structure.
Example IV
S1, providing a substrate layer capable of being wound, wherein the substrate layer is a composite current collector with a substrate of 8 mu mPET, and two sides of the composite current collector comprise aluminum layers with the thickness of 1 micrometer;
s2, providing a first conductive filler and a first aggregation regulator, wherein the first conductive filler and the first aggregation regulator are the same as the second conductive filler and the second aggregation regulator in the third embodiment;
S3, forming a metal layer on the outer surface of the first conductive filler layer, wherein the metal layer is an aluminum layer with the thickness of 0.1 mu m, and performing vapor deposition;
s4 provides a second conductive filler and a second aggregation regulator as in S2, except that the thickness of the coating is about 10 mu m, and after drying, the surface roughness is measured to be 5.2 mu m, so that the composite current collector with the surface three-layer structure is obtained.
Example five
S1, providing a substrate layer capable of being wound, wherein the substrate layer is a composite current collector with a7 mu mPP substrate, and two sides of the composite current collector comprise aluminum layers with 0.5 mu m each;
S2, providing a first conductive filler and a first aggregation regulator, wherein the first conductive filler and the first aggregation regulator are the same as those in the first embodiment, and the difference is that the coating thickness is about 2 mu m, and the surface roughness after drying is about 1.0 mu m;
S3, forming a metal layer on the outer surface of the first conductive filler layer, wherein the metal layer is an aluminum layer with the thickness of 1 mu m, and performing vapor deposition;
S4 provides a second conductive filler and a second agglomeration regulator as in S2.
S5, repeating the unit layer structure once to form a current collector structure with six layers on the surface.
Example six
The difference from the fifth example is that the single coating thickness in S2, S4 is 0.5 μm and the agglomeration amount is controlled to be about 3% (the addition amount of the dispersant is 1.5%), wherein the surface roughness after the single coating is about 0.15 μm and the coating is performed only once.
Example seven
The difference from the sixth embodiment is that the first conductive filler provided in S2 includes graphene oxide sheets of 0.5 μm and conductive carbon black of 0.3 μm, the concentration of GO is controlled to be 0.5g/L, the solid content of the system is controlled to be 25%, the second aggregation regulator is dilute sulfuric acid solution, the pH is 2, and the content is 8% of the mass of the conductive filler slurry, and the dispersion system is atomized and sprayed; the thickness of single coating is about 0.3 μm, and the surface roughness is 0.1 μm;
S4, selecting 50nm nickel powder from a second conductive filler layer, dispersing the nickel powder in ethanol (ultrasonically), adding SBR (styrene butadiene rubber) with the mass of 5% of aluminum powder into the solution, controlling the solid content of the first conductive nickel powder to be 20%, controlling the dosage of the first agglomeration regulator to be 2.5% of dispersant Disperbyk106 which is a dispersant added in ethanol in advance, fully stirring and dispersing the mixture to prepare a suspension, forming a small amount of agglomerated nickel powder (the agglomeration amount is about 2%), and immediately performing coating operation to obtain a single coating thickness of 0.1 mu m and a surface roughness of about 0.05 mu m;
The procedure was repeated twice.
Comparative example one: according to the normal dispersant addition amount in the first example, the relevant slurry was prepared, and the other conditions were the same, and the measured surface roughness was only 1.3. Mu.m.
Peel strength test
The first example was 135.3N/m, the second example was 125.8N/m, the third example was 142.3N/m, the fourth example was 148.6N/m, and the fifth example was 140.7N/m; example six is 132.4N/m; embodiment seven is 136.6N/m; comparative example one was 108.8N/m.
The method has the advantages that the stripping strength can be further improved by adjusting the GO agglomeration mode in an acidic atmosphere, probably because certain corrosion is generated between the GO and aluminum, the permeation effect of a coating interface is increased, and then the binding force is improved, meanwhile, because the agglomeration is carried out in a mode of forming agglomerates by coating for multiple times, the agglomeration mainly occurs on the surface layer of the coating in cooperation with the pushing of gas generated by corrosion, the roughness of the surface of the formed coating is improved, and a certain gas-flushed hole is generated between the large-particle-size agglomeration and the conductive filler in the outward discharge process of the generated gas, so that the permeation of metal layer molecules in the subsequent surface metal layer forming process is facilitated.
In the present application, components or processes not described in detail are all known in the art, and detailed components and process methods thereof are not described herein.
In the description of the present invention, it should be noted that the positional or positional relationship indicated by "upper, lower, inner and outer" or the like in terms is merely for convenience of describing the present invention and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first, second, or third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (10)
1. A multi-layered structure current collector comprising:
a base layer having two surfaces in the thickness direction;
The conductive layer is arranged on at least one surface of the matrix layer and comprises at least one group of unit layers with a first conductive filler layer, a metal layer and a second conductive filler layer which are sequentially compounded as a circulating matrix;
the first conductive filler layer and/or the second conductive filler layer comprises uniformly or unevenly distributed aggregates formed on the surface layer so as to increase the adhesion capability of the metal layer, wherein the aggregates have relatively larger particle size distribution than the conductive filler and are distributed on the surface layer of the corresponding conductive filler layer.
2. The multilayer structure current collector of claim 1, wherein the surface roughness of the first and/or second conductive filler layers is 20% -50% of the corresponding coating thickness.
3. The method for manufacturing a multilayer structure current collector according to claim 1 or 2, comprising the steps of:
S1, providing a substrate layer capable of being wound;
s2, providing a first conductive filler and a first aggregation regulator to form a first conductive filler layer on the outer surface of the matrix layer;
S3, forming a metal layer on the outer surface of the first conductive filler layer;
s4, providing a second conductive filler and a second aggregation regulator to form a second conductive filler layer on the outer surface of the matrix layer;
s5, selecting the circulation times according to actual needs to obtain the multilayer structure current collector with a certain thickness.
4. A method of producing a multilayer structure current collector according to claim 3, wherein the thickness of the base layer is 1 to 20 μm;
The substrate layer is a metal foil; or, a composite current collector; or, a polymer film;
The thickness of the metal layer is controlled to be 0.1-1 mu m.
5. The method for preparing a multilayer structure current collector according to claim 3, wherein the conductive filler in the first conductive filler layer and/or the second conductive filler layer comprises nanoscale chromium, nickel, metal alloys thereof, carbon-based filler or combinations thereof, and the particle size is selected to be 50-200nm; the solid content of the conductive filler is 10-30%; the first conductive filler layer and/or the second conductive filler layer also comprises a binder, and the mass ratio of the binder to the conductive filler is (0.02-0.05): 1; the binder is at least one of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose and SBR; the thickness of the first conductive filler layer and the second conductive filler layer is 0.1-20 μm.
6. The method for preparing a multilayer structure current collector according to claim 5, wherein the first aggregation regulator and/or the second aggregation regulator comprises a dispersant and a solvent having a lower threshold content, and the solvent is easily volatilized to form a gas during drying.
7. The method for producing a multilayer structure current collector according to claim 6, wherein the lower threshold content is set to be such that when the conductive filler is agglomerated in the solvent, the particle size distribution thereof is shifted by 5 to 10% by agglomeration; wherein the consumption of the dispersing agent is 0.5-5% of the mass of the conductive filler.
8. The method for preparing a multilayer structure current collector according to claim 3, wherein the first conductive filler and/or the second conductive filler comprises nano graphene oxide and nano conductive filler, and the nano graphene oxide and the nano conductive filler are dispersed in a solvent to obtain conductive filler slurry; wherein, the concentration of the graphene oxide is controlled to be 0.5-1g/L, the solid content of the conductive filler is controlled to be 10% -30%, and the coating is carried out after the conductive filler is fully dispersed;
Wherein the width of the graphene oxide is 0.5-3 mu m, and the particle size of the nano conductive filler is 0.1-0.5 mu m.
9. The method for preparing a multilayer structure current collector according to claim 8, wherein the first aggregation regulator and/or the second aggregation regulator is/are set to be an acidic regulator, the pH is controlled to be 1.5-2, the mass ratio of the additive amount to the conductive filler slurry is (0.08-0.1): 1, and the slurry is coated into the conductive filler slurry by spraying or coating, and further heated and dried.
10. The method for manufacturing a multilayer structure current collector according to claim 8 or 9, wherein the metal layer is made of an aluminum-containing or aluminum-containing alloy material;
the matrix layer is a metal foil containing aluminum and aluminum copper alloy; or a composite current collector, wherein the conductive material of the composite current collector is aluminum or copper-aluminum alloy material.
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