A water-based carbon coating slurry for functional current collectors, a preparation method and application thereof

Abstract

The present application belongs to the technical field of lithium ion battery materials, and provides a water-based carbon-coated slurry for functional current collector, a preparation method and application thereof. The water-based carbon-coated slurry comprises a conductive agent, a binder, an interface conductive bridging agent and a solvent; the interface conductive bridging agent comprises an alkyl phenolic resin oil-soluble oligomer, the alkyl phenolic resin oil-soluble oligomer comprises a carbonization precursor chain segment as a skeleton, and an oleophilic anchoring chain segment and a hydrophilic dispersion chain segment grafted as side groups on the skeleton. The interface conductive bridging agent added in the water-based carbon-coated slurry can directly treat oil stains, convert the oil stain interface in situ into an interface with excellent electron transmission capacity, greatly reduce the interface contact resistance, eliminate the need for foil pre-cleaning, realize the "waste to treasure" of harmful oil stains, significantly improve the rate performance and first-week efficiency of the battery, and achieve the multiple goals of simplifying the process, reducing the cost and improving the battery performance.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery material technology, specifically relating to a functional current collector water-based carbon coating slurry, its preparation method, and its application. Background Technology

[0002] In the positive electrode of lithium-ion batteries, aluminum foil is usually used as the functional current collector. In order to further reduce the interfacial contact resistance and improve the adhesion between the active material layer and the aluminum foil, an aqueous conductive carbon layer is often pre-coated on the surface of the aluminum foil to form carbon-coated aluminum foil.

[0003] During the industrial rolling process of aluminum foil, rolling oil stains inevitably remain on the surface of the aluminum foil. The main components of this type of oil stains are long-chain alkanes, esters and other organic substances, which will form an insulating layer on the surface of the aluminum foil. When a water-based conductive carbon layer is directly coated, this oil stain layer will hinder the electronic conduction between the conductive carbon layer and the aluminum foil, resulting in a significant increase in interface resistance, which seriously affects the rate performance and cycle life of lithium-ion batteries.

[0004] To overcome the aforementioned problems, the industry currently employs rigorous chemical cleaning processes (such as alkaline washing and acid washing) to pretreat aluminum foil and remove oil stains. While this process can improve interfacial conductivity to some extent, it is complex, energy-intensive, generates wastewater, and significantly increases production costs. Furthermore, some studies have attempted to improve coating spreadability by adding common wetting agents to the carbon coating slurry, but these methods cannot fundamentally eliminate the high interfacial resistance problem caused by oil stains.

[0005] Therefore, how to effectively suppress or eliminate the adverse effects of residual rolling oil on the surface of foil on the interfacial resistance and electron transport of the carbon coating layer is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a functional current collector water-based carbon coating slurry, its preparation method, and its application. The present invention adds an interfacial conductive bridging agent to the water-based carbon coating slurry. This interfacial conductive bridging agent can directly treat oil stains, possessing the ability to transform the insulating oil stain interface in situ into an interface with excellent electron transport capabilities. This significantly reduces interfacial contact resistance, thereby completely eliminating the need for pre-cleaning of the foil, realizing the "turning waste into treasure" of harmful oil stains, and significantly improving the rate performance and first-cycle efficiency of the battery. This achieves multiple goals of simplifying the process, reducing costs, and improving battery performance, providing an innovative material solution for the manufacture of high-performance lithium batteries.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a functional current collector water-based carbon coating slurry, the water-based carbon coating slurry comprising a conductive agent, a binder, an interfacial conductive bridging agent, and a solvent.

[0008] The interfacial conductive bridging agent includes an alkylphenol resin oil-soluble oligomer, which comprises a carbonized precursor chain segment as a backbone, and oleophilic anchoring chain segments and hydrophilic dispersing chain segments grafted onto the backbone as side groups.

[0009] This invention adds an interfacial conductive bridging agent (the structure can be represented as an oleophilic anchoring segment - a carbonized precursor segment - a hydrophilic dispersion segment) to an aqueous carbonized slurry. This interfacial conductive bridging agent can directly treat oil stains and has the ability to transform the insulating oil stain interface in situ into an interface with excellent electron transport capabilities. It can significantly reduce the interfacial contact resistance, thereby completely eliminating the need for pre-cleaning of the foil and realizing the "turning waste into treasure" of harmful oil stains. Through the synergistic carbonization effect, it transforms the oil stains into part of the conductive interface, significantly improving the rate performance and first-cycle efficiency of the battery. This achieves multiple goals of simplifying the process, reducing costs, and improving battery performance, providing an innovative material solution for the manufacturing of high-performance lithium batteries.

[0010] The mechanism by which the interfacial conductive bridging agent added to the water-based carbon coating slurry of this invention can remove oil in situ and improve the conductivity of the carbon coating layer is as follows: Alkylphenol resin oil-soluble oligomers, through the similar compatibility between the long-chain alkyl groups in their molecules and oil, first embed and encapsulate the oil film, achieving initial interfacial wetting and anchoring. Simultaneously, under heat treatment conditions, the active phenolic resin structure undergoes self-crosslinking and curing, and catalyzes the dehydrogenation aromatization reaction of oil molecules, transforming the insulating oil components into carbon precursors. Finally, in subsequent high-temperature treatment, these coexisting carbon precursors undergo in-situ carbonization, constructing a continuous, dense, and highly conductive carbon-based interfacial layer between the foil and the carbon coating layer. This simultaneously achieves the removal of harmful oil and the construction of interfacial electron transport channels, achieving the dual purpose of oil removal and conductivity enhancement.

[0011] Preferably, the oleophilic anchoring segment comprises C4-C12 long-chain alkyl and / or polyether segments. The C4-C12 long-chain alkyl group may be, for example, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, or n-dodecyl, etc.

[0012] In this invention, the function of the long-chain alkyl and / or polyether segments is to have a similar compatibility with oil stains, thereby anchoring the interfacial conductive bridging agent at the oil stain interface.

[0013] Preferably, the carbonized precursor segment is a segment containing an aromatic ring and having a crosslinkable group; the crosslinkable group includes any one or a combination of at least two of hydroxymethyl, methoxy, or epoxy groups.

[0014] Preferably, the hydrophilic dispersion segment comprises polyethylene glycol chains and / or carboxylate groups.

[0015] In this invention, the polyethylene glycol chain and / or carboxylate group function to provide steric stabilization and / or electrostatic repulsion, thereby achieving uniform dispersion of the interfacial conductive bridging agent in the aqueous system.

[0016] Preferably, the molar ratio of the oleophilic anchoring segment, the carbonized precursor segment, and the hydrophilic dispersing segment is (0.5-2):1:(0.4-2), wherein the range of the oleophilic anchoring segment "0.5-2" can be, for example, 0.5, 1, 1.5, or 2, and the range of the hydrophilic dispersing segment "0.4-2" can be, for example, 0.4, 0.5, 1, 1.5, or 2.

[0017] In the alkylphenol resin oil-soluble oligomer used in this invention, the oleophilic anchoring segment, the carbonized precursor segment, and the hydrophilic dispersing segment satisfy the above relationship. This can optimize the balance between the oleophilic anchoring ability, the carbonized precursor crosslinking to carbon ability, and the hydrophilic dispersing ability, ensuring that the interfacial conductive bridging agent can effectively anchor oil stains, stably disperse in aqueous systems, and form a continuous and dense conductive carbon interfacial layer after heat treatment.

[0018] Preferably, based on the total solid mass of the water-based carbon coating slurry, the mass content of the interfacial conductive bridging agent is 1-5 wt%, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%.

[0019] In this invention, an appropriate amount of interfacial conductive bridging agent can ensure stable dispersion of the slurry while achieving sufficient anchoring and efficient carbon conversion of the oil-contaminated interface. This avoids slurry thickening or increased costs due to excessive addition, as well as incomplete oil treatment and insignificant reduction in interfacial resistance due to insufficient addition.

[0020] Preferably, the conductive agent comprises conductive carbon black and / or graphite.

[0021] Preferably, the conductive agent comprises conductive carbon black and graphite, and the mass ratio of the conductive carbon black to graphite is (1-2):1, for example, it can be 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, etc. For example, the graphite can be artificial graphite or natural graphite, etc.

[0022] This invention uses two conductive materials: conductive carbon black and graphite. The "dot" network of carbon black and the "sheet" network of graphite intertwine to form a three-dimensional conductive structure, which helps to further improve the conductivity of the carbon coating layer.

[0023] Preferably, based on the total solid mass of the water-based carbon coating slurry, the mass content of the conductive agent is 50-70 wt%, for example, it can be 50 wt%, 55 wt%, 60 wt%, 65 wt%, or 70 wt%.

[0024] Preferably, the adhesive comprises polyacrylic acid.

[0025] Preferably, based on the total solid mass of the water-based carbon coating slurry, the mass content of the binder is 30-50 wt%, for example, it can be 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0026] Preferably, in the solid components of the water-based carbon coating slurry, the mass ratio of binder, conductive agent, and interfacial conductive bridging agent is (30-48):(50-68):(1-5), wherein the binder is selected from the range "30-48", for example, 30, 35, 40, 45, 47, or 48; the conductive agent is selected from the range "50-68", for example, 50, 55, 60, 65, 67, or 68; and the interfacial conductive bridging agent is selected from the range "1-5", for example, 1, 2, 3, 4, or 5.

[0027] In this invention, the binder, conductive agent, and interfacial conductive bridging agent satisfy the above-mentioned quality relationship, which can ensure that the carbon coating layer has sufficient structural integrity and flexibility (through the binder), forms an efficient three-dimensional electronic conduction network (through the conductive agent), and achieves sufficient oil stain anchoring and interfacial carbon conversion (through the interfacial conductive bridging agent), thereby achieving synergistic optimization of mechanical properties, conductive properties, and interfacial treatment capabilities among the three.

[0028] Preferably, the aqueous carbon coating slurry further includes a pH adjuster. For example, it could be a sodium hydroxide solution.

[0029] Preferably, the pH of the aqueous carbon coating slurry is 6-8, for example, it can be 6, 6.5, 7, 7.5 or 8.

[0030] This invention ensures that the pH of the water-based carbon coating slurry is 6-8, which is beneficial to improving the uniformity and dispersibility of the slurry.

[0031] Preferably, the aqueous carbon coating slurry further includes a wetting agent. Exemplary examples include polyether siloxane, modified polyether siloxane, or alcohol reagents, such as isopropanol.

[0032] The main function of adding a wetting agent in this invention is to reduce the surface tension of the slurry and improve the film quality of the carbon coating layer.

[0033] Preferably, the solid content of the water-based carbon coating slurry is 15-30 wt%, for example, it can be 15 wt%, 20 wt%, 25 wt%, or 30 wt%.

[0034] In a second aspect, the present invention provides a method for preparing a functional current collector water-based carbon coating slurry as described in the first aspect, the preparation method comprising the following steps: The conductive agent, adhesive, interfacial conductive bridging agent and solvent are mixed to obtain the functional current collector water-based carbon coating slurry.

[0035] Preferably, the preparation steps of the interfacial conductive bridging agent include: Alkylphenol, catalyst, and formaldehyde solution are mixed and subjected to a condensation reaction to obtain an oil-soluble phenolic oligomer; wherein the alkylphenol contains an alkyl side chain.

[0036] The oil-soluble phenolic oligomer, polyethylene glycol monomethyl ether, and catalyst are mixed and subjected to an ether exchange reaction to obtain the grafted product.

[0037] The grafted product is subjected to pH adjustment and emulsification dispersion to obtain the interfacial conductive bridging agent.

[0038] In this invention, the ether exchange reaction is a chemical grafting process in which the terminal hydroxyl group of polyethylene glycol monomethyl ether reacts with the terminal hydroxymethyl group of the phenolic oligomer.

[0039] It should be noted that whether oil-soluble phenolic oligomers have been formed can be detected by the following method: take a small amount of the reactant, dissolve it in ethanol, and drop it into water. If a milky white turbidity appears and does not dissipate, it indicates that oil-soluble oligomers with a certain molecular weight have been formed.

[0040] It should be noted that the success of chemical grafting can be tested in the following way: test the dispersibility of the grafted product in warm water. If it can change from hydrophobic to spontaneously dispersible, it indicates that the grafting was successful.

[0041] Preferably, the temperature of the condensation reaction is 100-105℃, for example, 100℃, 101℃, 102℃, 103℃, 104℃ or 105℃, and the time is 3-4h, for example, 3h, 3.2h, 3.5h, 3.8h or 4h.

[0042] In this invention, by using appropriate condensation reaction temperature and time, the degree of reaction can be controlled to obtain phenolic oligomers with suitable molecular weight and oil solubility. This avoids the problem of insufficient reaction leading to low oligomer molecular weight and poor oil solubility, as well as excessive reaction leading to excessive molecular weight, excessive crosslinking, and decreased activity in subsequent grafting reactions.

[0043] Preferably, the alkylphenol includes p-octylphenol.

[0044] Preferably, the atmosphere for the ether exchange reaction is an inert atmosphere. For example, it may be a nitrogen atmosphere or an argon atmosphere.

[0045] Preferably, the temperature of the ether exchange reaction is 120-125℃, for example, 120℃, 121℃, 122℃, 123℃, 124℃ or 125℃, and the time is 2-3h, for example, 2h, 2.2h, 2.5h, 2.8h or 3h.

[0046] In this invention, under suitable temperature and time for the ether exchange reaction, sufficient etherification reaction can be promoted between the hydroxymethyl groups at the end of the oil-soluble phenolic oligomer and the terminal hydroxyl groups of polyethylene glycol monomethyl ether, thereby achieving effective grafting of polyethylene glycol segments. At the same time, side reactions (such as excessive cross-linking of phenolic resin and thermal oxidative degradation of polyether chains) caused by excessively high temperature or time are avoided, as well as insufficient grafting rate and substandard hydrophilic dispersion ability caused by excessively low temperature or time.

[0047] Preferably, the preparation method includes the following steps: (1) Preparation of alkylphenol resin oil-soluble oligomers, the steps include: (1-1) At 90-95℃ (e.g., 90℃, 91℃, 92℃, 93℃, 94℃ or 95℃, etc.), p-octylphenol and an acidic catalyst are mixed evenly, and then formaldehyde solution is added dropwise at 95-100℃ (e.g., 95℃, 96℃, 97℃, 98℃, 99℃ or 100℃, etc.). After the addition is complete, a condensation reaction is carried out at 100-105℃ for 3-4 hours to obtain an oil-soluble phenolic oligomer; wherein, the acidic catalyst includes oxalic acid.

[0048] (1-2) The oil-soluble phenolic oligomer, polyethylene glycol monomethyl ether and acidic catalyst are stirred and mixed at 75-85℃ (e.g., 75℃, 78℃, 80℃, 82℃ or 85℃, etc.), and then an ether exchange reaction is carried out at 120-125℃ for 2-3 hours to obtain the grafted product; wherein the acidic catalyst includes p-toluenesulfonic acid.

[0049] (1-3) At ≤60℃ (e.g., 60℃, 55℃, 50℃, 45℃, 40℃ or 35℃, etc.), the pH of the grafted product is adjusted to 7-8 (e.g., 7, 7.2, 7.5, 7.8 or 8, etc.), and then water is added under stirring to emulsify and disperse, thereby obtaining an aqueous dispersion.

[0050] The aqueous dispersion is purified and concentrated to obtain an emulsion containing the alkylphenol resin oil-soluble oligomer; the solid content of the emulsion is 35-45% (for example, it can be 35%, 38%, 40%, 42% or 45%, etc.).

[0051] (2) Mix the adhesive solution with water at a viscosity of 800-3000 mPa·s (e.g., 800 mPa·s, 1000 mPa·s, 1500 mPa·s, 2000 mPa·s, 2500 mPa·s, or 3000 mPa·s, etc.) and a solid content of 15-25 wt% (e.g., 15 wt%, 18 wt%, 20 wt%, 22 wt%, or 25 wt%, etc.), and at 1000-1200 rpm (e.g., 1000 rpm, 1100 rpm, or 1200 rpm, etc.). Disperse the adhesive at a stirring rate of 20-40 min (e.g., 20 min, 25 min, 30 min, 35 min, or 40 min, etc.) to obtain an adhesive diluent with a solid content of 5-10 wt% (e.g., 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.) and a viscosity of 200-800 mPa·s (e.g., 200 mPa·s, 400 mPa·s, 600 mPa·s, or 800 mPa·s, etc.); wherein the adhesive solution includes polyacrylic acid adhesive solution.

[0052] (3) Mix the emulsion described in step (1) and the binder dilution described in step (2), and disperse at a stirring rate of 1000-1200 rpm (e.g., 1000 rpm, 1100 rpm or 1200 rpm, etc.) for 5-15 min (e.g., 5 min, 8 min, 10 min, 12 min or 15 min, etc.) to obtain the first mixture.

[0053] (4) Add a conductive agent with a mass fraction of w1 to the first mixture and disperse it at a stirring rate of 1500-1800 rpm (e.g., 1500 rpm, 1600 rpm, 1700 rpm, or 1800 rpm, etc.) for 20-40 minutes (e.g., 20 minutes, 25 minutes, 30 minutes, 35 minutes, or 40 minutes, etc.). Then add a conductive agent with a mass fraction of w2 and disperse it at a stirring rate of 2000-2600 rpm (e.g., 2000 rpm, 2200 rpm, 2400 rpm, or 2600 rpm, etc.). The mixture is subjected to a concentration of 0-40 min (e.g., 20 min, 25 min, 30 min, 35 min, or 40 min) to obtain a second mixture; wherein, w1:w2 = (0.4-0.6):(0.4-0.6) (the selection range of w1 "0.4-0.6" can be, for example, 0.4, 0.45, 0.5, 0.55, or 0.6, and the selection range of w2 "0.4-0.6" can be, for example, 0.4, 0.45, 0.5, 0.55, or 0.6), and w1+w2=1; the conductive agent includes conductive carbon black and graphite in a mass ratio of (1-2):1.

[0054] (5) Add water to the second mixture until the solid content is 15-25wt% (e.g., 15wt%, 20wt%, or 25wt%), and disperse at a stirring rate of 2000-2600rpm (e.g., 2000rpm, 2200rpm, 2400rpm, or 2600rpm) for 20-40min (e.g., 20min, 25min, 30min, 35min, or 40min). Then add a pH adjuster to adjust the pH of the slurry system to 6-8, add a wetting agent, and disperse at a stirring rate of 10-15rpm (e.g., 10rpm, 11rpm, 12rpm, 13rpm, 14rpm, or 15rpm) for 30-45min (e.g., 30min, 35min, 40min, or 45min). After that, perform homogenization treatment to obtain the functional current collector water-based carbon coating slurry.

[0055] Preferably, during the homogenization process, the pressure is 500-700 bar, for example, 500 bar, 600 bar, or 700 bar.

[0056] The present invention does not limit the number of homogenization processes; for example, it may be 1 time, 2 times, or 3 times.

[0057] Thirdly, the present invention provides a functional current collector comprising a foil and a carbon coating layer disposed on at least one surface of the foil, the carbon coating layer being prepared by coating and heat treatment using an aqueous carbon coating slurry as described in the first aspect.

[0058] The water-based carbon coating slurry provided by this invention can be directly coated on unwashed, oily industrial aluminum foil, and its penetration resistance is significantly reduced (as low as 2.5mΩ).

[0059] Preferably, the foil material includes aluminum foil.

[0060] Preferably, the thickness of the carbon coating layer on one side is 0.5-1.5 μm, for example, it can be 0.5 μm, 1 μm or 1.5 μm.

[0061] Preferably, the heat treatment temperature is 150-250℃, for example, it can be 150℃, 175℃, 200℃, 225℃ or 250℃.

[0062] The present invention does not limit the coating method of the carbon coating layer. For example, the slot coating method can be used.

[0063] Fourthly, the present invention provides a lithium-ion battery, wherein the electrodes of the lithium-ion battery include the functional current collector as described in the third aspect.

[0064] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0065] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adds an interfacial conductive bridging agent to the water-based carbon coating slurry. This interfacial conductive bridging agent can directly treat oil stains and has the ability to transform the insulating oil stain interface in situ into an interface with excellent electron transport capability. It can significantly reduce the interfacial contact resistance, thereby completely eliminating the need for pre-cleaning of foil materials and realizing the "turning waste into treasure" of harmful oil stains. Through the synergistic carbonization effect, it transforms them into part of the conductive interface, significantly improving the rate performance and first-cycle efficiency of the battery. Thus, it achieves multiple goals of simplifying the process, reducing costs and improving battery performance, and provides an innovative material solution for the manufacturing of high-performance lithium batteries.

[0066] (2) The water-based carbon coating slurry provided by the present invention has low cost and is conducive to its widespread use. Detailed Implementation

[0067] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0068] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0069] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0070] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0071] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0072] It should be noted that the specifications of the raw materials required for preparing the alkylphenol resin oil-soluble oligomers in the following embodiments are as follows: ① 4-Octylphenol, purchased from Sinopharm Group, model TCI-O0562, 98.0% (GC), 25g, Sinopharm code TO056225G; ② Formaldehyde, purchased from Sinopharm Group, model Acros-410730050, 5kg, Sinopharm code C410730050, to be prepared into a 37wt% formaldehyde solution; ③ Polyethylene glycol monomethyl ether, purchased from Sinopharm Group, model TCI-P2183, 500g, Sinopharm code TP2183500G; ④ Herbs ⑤ Sodium hydroxide, purchased from Sinopharm Group, model Acros-423150010, 1kg, Sinopharm code C423150010; ⑥ Deionized water, self-made; ⑦ Anhydrous ethanol, purchased from Sinopharm Group, model GR (Shanghai Test), ≥99.9%, 500mL, Sinopharm code 10009259; ⑧ p-Toluenesulfonic acid, purchased from Sinopharm Group, model 99% (Wokai), 25g, Sinopharm code XW0110415404.

[0073] It should be noted that the specifications of the raw materials required for preparing the water-based carbon coating slurry in the following embodiments are as follows: ① Water-based polyacrylic acid (PAA), purchased from Linte Technology, model 7002; ② Deionized water, self-made; ③ Conductive carbon black, purchased from Cabot Chemical, model SHYT-150P; ④ Conventional graphite, purchased from Sinopharm Group, model: CP (Shanghai Test), ≥99.85%, 100g, Sinopharm code 20019126; ⑤ Isopropanol, purchased from Sinopharm Group, model: LC-MS (Shanghai Test), 4L, Sinopharm code 40064361; ⑥ Sodium hydroxide, purchased from Sinopharm Group, model: AR (Shanghai Test) (flakes), 500g, Sinopharm code 10019764; ⑦ Alkylphenol resin oil-soluble oligomer, self-made.

[0074] Example 1 This embodiment provides a functional current collector water-based carbon coating slurry, which includes a conductive agent, a binder, an interfacial conductive bridging agent, a pH adjuster, a wetting agent, and deionized water.

[0075] The interfacial conductive bridging agent is an alkylphenol resin oil-soluble oligomer, which includes a carbonized precursor segment as a backbone, and oleophilic anchoring segments and hydrophilic dispersing segments grafted onto the backbone as side groups. The oleophilic anchoring segment is a C8 long-chain alkyl group; the carbonized precursor segment is a segment containing an aromatic ring and having a crosslinkable group, wherein the crosslinkable group is hydroxymethyl; the hydrophilic dispersing segment is a polyethylene glycol chain; the molar ratio of the oleophilic anchoring segment, the carbonized precursor segment, and the hydrophilic dispersing segment is 1:1:0.4; and the mass content of the alkylphenol resin oil-soluble oligomer is 5 wt% based on the total solid mass of the aqueous carbon coating slurry.

[0076] The conductive agent comprises conductive carbon black and artificial graphite in a mass ratio of 1:1; based on the total solid mass of the aqueous carbon coating slurry, the mass content of the conductive agent is 65 wt%; the binder is PAA; based on the total solid mass of the aqueous carbon coating slurry, the mass content of the binder is 30 wt%; in the solid components of the aqueous carbon coating slurry, the mass ratio of binder, conductive agent, and interfacial conductive bridging agent is 30:65:5; the pH adjuster is sodium hydroxide solution; the pH of the aqueous carbon coating slurry is 7; the wetting agent is isopropanol, added at 10% of the total mass of the aqueous carbon coating slurry; the solid content of the aqueous carbon coating slurry is 20 wt%.

[0077] This embodiment also provides a method for preparing the above-mentioned functional current collector water-based carbon coating slurry, the preparation method including the following steps: (1) Preparation of alkylphenol resin oil-soluble oligomers, the steps include: (1-1) In a dry 250mL three-necked flask, add 40g of p-octylphenol and 0.5g of oxalic acid. Install a stirrer, condenser and thermometer. Heat in an oil bath to 92℃ to completely melt the p-octylphenol. Then, under stirring, slowly add 25g of 37% formaldehyde solution dropwise using a constant pressure dropping funnel, controlling the dropping time to within 1 hour and the temperature to 98℃. After the addition is complete, raise the temperature to 102℃ and carry out a condensation reaction for 3.5 hours. After the reaction is completed, a brownish-red viscous liquid is obtained, which is the oil-soluble phenolic oligomer. During the condensation reaction, a simple water separator can be connected to the top of the condenser to observe the amount of water generated in the reaction to judge the progress of the reaction.

[0078] (1-2) The oil-soluble phenolic oligomer was cooled to 80°C, and then 30g of polyethylene glycol monomethyl ether and 0.1g of p-toluenesulfonic acid were added under stirring. The temperature was then raised to 122°C and an ether exchange reaction was carried out for 2.5h under a nitrogen atmosphere to obtain a viscous graft product.

[0079] (1-3) Cool the grafted product to 55°C, then add a 10% sodium hydroxide solution to adjust the pH of the grafted product to 7.5. Then, under stirring, slowly add 100 mL of deionized water preheated to 60°C for emulsification and dispersion, so that the system gradually changes from a viscous state to a brownish-brown semi-transparent to milky-white aqueous dispersion.

[0080] The aqueous dispersion was transferred to a separatory funnel and allowed to stand to separate any trace amounts of unreacted oily matter. The upper emulsion was collected. The upper emulsion was concentrated under reduced pressure at 55°C using a rotary evaporator to remove some water and volatile impurities. The solid content was finally adjusted to 40% to obtain a brownish-red homogeneous emulsion, which is the alkylphenol resin oil-soluble oligomer. It was then passed through a 200-mesh sieve for later use.

[0081] (2) In a 200L double star mixing tank, PAA adhesive solution with a viscosity of 1900mPa·s and a solid content of 20wt% was mixed with deionized water and dispersed at a stirring rate of 1100rpm for 30min to obtain an adhesive dilution solution with a solid content of 10wt% and a viscosity of 400mPa·s.

[0082] (3) Mix the emulsion described in step (1) and the binder dilution described in step (2), and disperse them at a stirring rate of 1100 rpm for 10 min to obtain the first mixture.

[0083] (4) Add a conductive agent with a mass fraction of w1 to the first mixture and disperse it at a stirring rate of 1650 rpm for 30 min. Then add a conductive agent with a mass fraction of w2 and disperse it at a stirring rate of 2300 rpm for 30 min to obtain a second mixture. Wherein, w1:w2=0.5:0.5 and w1+w2=1. The conductive agent includes conductive carbon black and graphite with a mass ratio of 1:1.

[0084] (5) Add deionized water to the second mixture until the solid content is 20wt%, and disperse at a stirring rate of 2300rpm for 30min. Then add 1mol / L sodium hydroxide solution to adjust the pH of the slurry system to 7, then add isopropanol, and disperse at a stirring rate of 12rpm for 40min. After the process, perform two homogenization treatments in a homogenizer at a pressure of 600bar to obtain the functional current collector water-based carbon coating slurry.

[0085] This embodiment also provides a functional current collector, which includes an aluminum foil and a carbon coating layer disposed on both sides of the aluminum foil. The carbon coating layer is prepared by using the water-based carbon coating slurry as described above through a slot coating method and heat treatment. The aluminum foil has a width of 300 mm and a thickness of 12 μm. The carbon coating layer has a single-sided thickness of 1 μm.

[0086] The preparation steps of the carbon coating layer include: uniformly coating the surface of the aluminum foil with water-based carbon coating slurry through a slot extrusion coating machine, setting the coating line speed to 60m / min; the coated wet film is heat-treated at 200℃, and then cooled and wound up.

[0087] Example 2 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the alkylphenol resin oil-soluble oligomer is 4 wt%, and the mass content of the conductive agent is 66 wt%.

[0088] The remaining preparation methods and parameters are consistent with those in Example 1.

[0089] Example 3 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the alkylphenol resin oil-soluble oligomer is 3 wt%, and the mass content of the conductive agent is 67 wt%.

[0090] The remaining preparation methods and parameters are consistent with those in Example 1.

[0091] Example 4 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the alkylphenol resin oil-soluble oligomer is 2 wt%, and the mass content of the conductive agent is 68 wt%.

[0092] The remaining preparation methods and parameters are consistent with those in Example 1.

[0093] Example 5 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the alkylphenol resin oil-soluble oligomer is 1 wt%, and the mass content of the conductive agent is 69 wt%.

[0094] The remaining preparation methods and parameters are consistent with those in Example 1.

[0095] Example 6 The difference between this embodiment and embodiment 1 is that the water-based carbon coating slurry does not contain a pH adjuster, that is, sodium hydroxide solution is not added in step (5).

[0096] The remaining preparation methods and parameters are consistent with those in Example 1.

[0097] Example 7 The difference between this embodiment and Example 1 is that the amount of polyethylene glycol monomethyl ether added in step (1) is adjusted so that the molar ratio of the carbonized precursor segment and the hydrophilic dispersion segment is 1:2.5.

[0098] The remaining preparation methods and parameters are consistent with those in Example 1.

[0099] Example 8 The difference between this embodiment and Example 1 is that the amount of polyethylene glycol monomethyl ether added in step (1) is adjusted so that the molar ratio of the carbonized precursor chain segment and the hydrophilic dispersion chain segment is 1:0.2.

[0100] The remaining preparation methods and parameters are consistent with those in Example 1.

[0101] Example 9 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the interfacial conductive bridging agent is 0.5 wt%.

[0102] The remaining preparation methods and parameters are consistent with those in Example 1.

[0103] Example 10 The difference between this embodiment and Embodiment 1 is that, based on the total solid mass of the water-based carbon coating slurry, the mass content of the interfacial conductive bridging agent is 8 wt%.

[0104] The remaining preparation methods and parameters are consistent with those in Example 1.

[0105] Comparative Example 1 The difference between this comparative example and Example 1 is that the water-based carbon coating slurry does not contain an interfacial conductive bridging agent, i.e., step (1) is not performed.

[0106] The remaining preparation methods and parameters are consistent with those in Example 1.

[0107] Comparative Example 2 The difference between this comparative example and Example 1 is that the alkylphenol resin oil-soluble oligomer does not contain hydrophilic dispersion segments, i.e., steps (1-2) are not performed.

[0108] The remaining preparation methods and parameters are consistent with those in Example 1.

[0109] Performance testing (i) The penetration resistance of the functional current collector provided in the above embodiments and comparative examples is tested. The steps include: taking several strips with a length and width of 20×5cm, cutting the strips into small samples of 5×5cm, testing the penetration resistance under a diaphragm resistance meter, and recording the test data.

[0110] (ii) Based on the functional current collectors provided in the above embodiments and comparative examples, a positive electrode sheet is fabricated, and then a lithium-ion battery is assembled. The steps include: A positive electrode slurry was prepared by uniformly mixing positive electrode active material (lithium iron phosphate), conductive carbon black, and polyvinylidene fluoride at a mass ratio of 96:2:2 and dispersing them in the solvent N-methylpyrrolidone. The positive electrode slurry was then uniformly coated onto both surfaces of the aforementioned functional current collector to form a positive electrode active coating. The coating was dried at 120°C for 8 hours under vacuum, followed by cold pressing and slitting to obtain the positive electrode sheet. A negative electrode active material, conductive carbon black, and Li4Ti5O were then mixed... 12 A negative electrode slurry was prepared by mixing the materials evenly in deionized water at a mass ratio of 93:5:2. The negative electrode slurry was then coated onto a carbon-coated current collector and dried at 120°C for 4 hours to obtain a negative electrode sheet. The positive and negative electrode sheets were stacked in sequence and injected with an electrolyte (i.e., a carbonate solution containing 1 mol / L lithium hexafluorophosphate, with the solvent consisting of EC / EMC / DMC in a volume ratio of 1:1:1). After vacuum sealing, settling, formation, and shaping, a lithium-ion battery was obtained.

[0111] The lithium-ion battery was subjected to cycle performance testing at room temperature (25℃): the battery was charged to 3.65V at 1C constant current and constant voltage with a cutoff current of 0.05C, and then discharged to 2.5V at 1C constant current. This constituted one charge-discharge cycle, which was repeated for 100 cycles. The discharge capacity of the first and 100th cycles was recorded, and the capacity retention rate was calculated according to the following formula: Capacity retention rate = (discharge capacity of the 100th cycle / discharge capacity of the 1st cycle) × 100%.

[0112] The lithium-ion battery was subjected to rate performance testing at room temperature (25℃): it was charged to 4.5V at a constant current and constant voltage rate of 0.2C, and then discharged to 3.0V at a constant current rate of 0.2C, and the 0.2C discharge capacity was recorded; subsequently, the same charge-discharge test was performed sequentially at a 5C rate, and the 5C discharge capacity was recorded. The capacity retention rate was calculated using the following formula: Capacity retention rate (%) = (5C discharge capacity / 0.2C discharge capacity) × 100%.

[0113] The test results are shown in Table 1.

[0114] Table 1 analyze: As shown in Table 1, this invention adds an interfacial conductive bridging agent to the aqueous carbon coating slurry. This interfacial conductive bridging agent can directly treat oil stains and has the ability to transform the insulating oil stain interface in situ into an interface with excellent electron transport capability. It can significantly reduce the interfacial contact resistance, thereby completely eliminating the need for pre-cleaning of the foil and realizing the "turning waste into treasure" of harmful oil stains. Through the synergistic carbonization effect, it transforms the oil stains into part of the conductive interface, significantly improving the rate performance and first-cycle efficiency of the battery. This achieves multiple goals of simplifying the process, reducing costs, and improving battery performance, providing an innovative material solution for the manufacturing of high-performance lithium batteries.

[0115] A comparison of Examples 1 and 6 shows that if the pH of the aqueous carbon coating slurry is not adjusted, the dispersion uniformity of the slurry decreases, resulting in an increase in the interfacial resistance of the carbon coating layer. The initial efficiency and rate performance of the battery are significantly reduced, but the cycle stability decreases relatively little. This indicates that pH adjustment has a significant impact on the slurry dispersion and interfacial conductivity.

[0116] A comparison of Examples 1 and 7-8 shows that if the molar ratio of carbonized precursor segments to hydrophilic dispersion segments is too small, the oleophilic anchoring ability of the interfacial conductive bridging agent is insufficient, failing to effectively anchor oil stains, resulting in a significant increase in penetration resistance and a substantial deterioration in first-efficiency, capacity retention, and rate performance. If the molar ratio of carbonized precursor segments to hydrophilic dispersion segments is too large, the water dispersibility of the interfacial conductive bridging agent deteriorates, and the uniformity of the slurry decreases. Although the penetration resistance and rate performance are better than the scheme with the smaller ratio, they are still significantly worse than Example 1. This indicates that a suitable three-segment ratio is crucial for balancing anchoring and dispersion capabilities.

[0117] A comparison of Examples 1 and 9-10 shows that if the mass content of the interfacial conductive bridging agent is too low, the oil stain interface treatment is insufficient, the penetration resistance is as high as 7.23 mΩ, the first-time efficiency is only 76.8%, the capacity retention rate is 70.5%, and the rate performance is 60.2%. All indicators are close to the comparative example level, and the technical effect of the present invention cannot be achieved. If the mass content of the interfacial conductive bridging agent is too high, the slurry viscosity is too high, the dispersibility decreases, and the cost increases. However, the interface treatment capability is still strong, with a penetration resistance of 3.98 mΩ, a first-time efficiency of 88.3%, a capacity retention rate of 85.5%, and a rate performance of 78.5%.

[0118] As can be seen from the comparison between Example 1 and Comparative Example 1, if the water-based carbon coating slurry does not contain an interfacial conductive bridging agent, it cannot treat the rolling oil stains on the surface of the aluminum foil. The oil stains, as an insulating layer, seriously hinder electron conduction, and the battery performance deteriorates significantly. This proves that the interfacial conductive bridging agent is the key component for achieving the "turning waste into treasure" effect of this invention.

[0119] As can be seen from the comparison between Example 1 and Comparative Example 2, if the alkylphenol resin oil-soluble oligomer does not contain hydrophilic dispersion segments, the interfacial conductive bridge agent cannot be stably dispersed in the aqueous system, the slurry will agglomerate and settle, the coating uniformity will be poor, and the penetration resistance will be significantly higher than that of Example 1. This proves that hydrophilic dispersion segments are the necessary structural units to achieve compatibility with aqueous processes.

[0120] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A functional water-based carbon coating slurry for current collection, characterized in that, The water-based carbon coating slurry includes a conductive agent, a binder, an interfacial conductive bridging agent, and a solvent. The interfacial conductive bridging agent includes an alkylphenol resin oil-soluble oligomer, which comprises a carbonized precursor chain segment as a backbone, and oleophilic anchoring chain segments and hydrophilic dispersing chain segments grafted onto the backbone as side groups.

2. The functional manifold water-based carbon coating slurry according to claim 1, characterized in that, The oleophilic anchoring segments include long-chain alkyl and / or polyether segments of C4-C12; And / or, the carbonized precursor segment is a segment containing an aromatic ring and having a crosslinkable group; the crosslinkable group includes any one or a combination of at least two of hydroxymethyl, methoxy, or epoxy groups; And / or, the hydrophilic dispersion segment comprises a polyethylene glycol chain and / or a carboxylate group; And / or, the molar ratio of the oleophilic anchoring segment, the carbonized precursor segment, and the hydrophilic dispersing segment is (0.5-2):1:(0.4-2).

3. The functional manifold water-based carbon coating slurry according to claim 1, characterized in that, Based on the total solid mass of the water-based carbon coating slurry, the mass content of the interfacial conductive bridging agent is 1-5 wt%.

4. The functional manifold water-based carbon coating slurry according to claim 1, characterized in that, The conductive agent includes conductive carbon black and / or graphite; And / or, based on the total solids mass of the water-based carbon coating slurry, the mass content of the conductive agent is 50-70 wt%; And / or, the adhesive comprises polyacrylic acid; And / or, based on the total solids mass of the water-based carbon coating slurry, the binder content is 30-50 wt%; And / or, in the solid components of the water-based carbon coating slurry, the mass ratio of binder, conductive agent and interfacial conductive bridging agent is (30-48):(50-68):(1-5); And / or, the water-based carbon coating slurry further includes a pH adjuster; And / or, the pH of the aqueous carbon coating slurry is 6-8; And / or, the water-based carbon coating slurry further includes a wetting agent; And / or, the solid content of the water-based carbon coating slurry is 15-30 wt%.

5. A method for preparing a functional current collector water-based carbon coating slurry as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: The conductive agent, adhesive liquid, interfacial conductive bridging agent and solvent are mixed to obtain the functional current collector water-based carbon coating slurry.

6. The preparation method according to claim 5, characterized in that, The preparation steps of the interfacial conductive bridging agent include: Alkylphenol, catalyst, and formaldehyde solution are mixed and subjected to a condensation reaction to obtain an oil-soluble phenolic oligomer; wherein the alkylphenol contains an alkyl side chain. The oil-soluble phenolic oligomer, polyethylene glycol monomethyl ether, and catalyst were mixed and subjected to an ether exchange reaction to obtain the grafted product. The grafted product is subjected to pH adjustment and emulsification dispersion to obtain the interfacial conductive bridging agent.

7. The preparation method according to claim 6, characterized in that, The condensation reaction is carried out at a temperature of 100-105℃ for 3-4 hours. And / or, the alkylphenol includes p-octylphenol; And / or, the atmosphere for the ether exchange reaction is an inert atmosphere; And / or, the ether exchange reaction is carried out at a temperature of 120-125°C for 2-3 hours.

8. The preparation method according to claim 5, characterized in that, The preparation method includes the following steps: (1) Preparation of alkylphenol resin oil-soluble oligomers, the steps include: (1-1) At 90-95℃, p-octylphenol and an acidic catalyst are mixed evenly, and then formaldehyde solution is added dropwise at 95-100℃. After the addition is complete, a condensation reaction is carried out at 100-105℃ for 3-4 hours to obtain an oil-soluble phenolic oligomer; wherein, the acidic catalyst includes oxalic acid. (1-2) The oil-soluble phenolic oligomer, polyethylene glycol monomethyl ether and acidic catalyst are stirred and mixed at 75-85℃, and then subjected to ether exchange reaction at 120-125℃ for 2-3 hours to obtain the grafted product; wherein the acidic catalyst includes p-toluenesulfonic acid. (1-3) At ≤60℃, the pH of the grafted product is adjusted to 7-8, and then water is added under stirring to emulsify and disperse it to obtain an aqueous dispersion; The aqueous dispersion is purified and concentrated to obtain an emulsion containing the alkylphenol resin oil-soluble oligomer; the solid content of the emulsion is 35-45%. (2) Mix an adhesive solution with a viscosity of 800-3000 mPa·s and a solid content of 15-25 wt% with water, and disperse it at a stirring rate of 1000-1200 rpm for 20-40 min to obtain an adhesive dilution with a solid content of 5-10 wt% and a viscosity of 200-800 mPa·s; wherein the adhesive solution includes polyacrylic acid solution; (3) Mix the emulsion described in step (1) and the binder dilution described in step (2), and disperse at a stirring rate of 1000-1200 rpm for 5-15 min to obtain the first mixture; (4) Add a conductive agent with a mass fraction of w1 to the first mixture and disperse it at a stirring rate of 1500-1800 rpm for 20-40 min. Then add a conductive agent with a mass fraction of w2 and disperse it at a stirring rate of 2000-2600 rpm for 20-40 min to obtain a second mixture. Wherein, w1:w2=(0.4-0.6):(0.4-0.6), and w1+w2=1. The conductive agent includes conductive carbon black and graphite with a mass ratio of (1-2):

1. (5) Add water to the second mixture until the solid content is 15-25wt%, and disperse at a stirring rate of 2000-2600rpm for 20-40min. Then add pH adjuster to adjust the pH of the slurry system to 6-8, then add wetting agent, and disperse at a stirring rate of 10-15rpm for 30-45min. After the process is completed, homogenize to obtain functional current collector water-based carbon coating slurry.

9. A functional current collector, characterized in that, The functional current collector includes a foil and a carbon coating layer disposed on at least one surface of the foil, wherein the carbon coating layer is prepared by coating and heat treatment using an aqueous carbon coating slurry as described in any one of claims 1-4.

10. A lithium-ion battery, characterized in that, The electrodes of the lithium-ion battery include the functional current collector as described in claim 9.

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