Functional current collector with high ductility and binding power as well as preparation method and application of functional current collector

Abstract

The invention discloses a functional current collector with high ductility and binding power as well as a preparation method and application thereof, and relates to the field of battery manufacturing. The preparation method comprises the following steps: 1, kneading silicone rubber and white carbon black to obtain a base material; adding the nickel-coated graphite powder, a cross-linking agent, a coupling agent and a catalyst into the base material, and uniformly mixing to obtain conductive slurry; 2, coating the surface of the substrate layer with conductive slurry, and vulcanizing to obtain a conductive adhesive layer; the membrane is a composite membrane; and step 3, plating a metal layer on the surface of the composite film through a water plating process to obtain the functional current collector. The preparation method has the beneficial effects that the functional current collector prepared by the preparation method has excellent ductility and binding power.

Description

Technical Field

[0001] The present invention relates to the field of battery manufacturing, and in particular to a high-ductility, high-adhesion functional current collector and a preparation method and application thereof. Background Art

[0002] Currently, copper foil and aluminum foil are mostly used as current collectors for the positive and negative electrodes in lithium batteries and sodium batteries. This type of current collector has high cost and quality, which is not conducive to controlling battery costs and improving energy density. In this regard, composite foil has obvious advantages over traditional foil. The metal layer on the surface of the composite foil is thinner, and the polymer layer inside is lighter, which makes it possible to greatly reduce the overall weight of the current collector, thereby increasing the energy density of the lithium-ion battery; at the same time, the thinner metal layer on the surface of the functional current collector is easier to disconnect than the current collector of traditional foil when the lithium-ion battery experiences thermal runaway, thereby isolating the connection between the active material and the current collector, preventing the lithium-ion battery from continuing to experience thermal runaway.

[0003] Composite foil current collectors are usually a "sandwich" structure, with an inner layer of polymer high molecular weight and metal conductive layers on both sides. Among the functional current collectors currently produced in industrial quantities, composite copper current collectors usually use PE polyethylene base film as the inner polymer high molecular weight layer. However, the PE polyethylene base film has poor ductility and poor adhesion to the metal layer, which in turn affects the energy density, cycle life and safety of the battery. When making a composite copper current collector, it is necessary to magnetron sputter-plate a 30-60nm transition copper layer on both sides of the base film, and then thicken the copper layer to about 1 μm by water electroplating to obtain a functional copper current collector. The magnetron sputtering equipment required for the magnetron sputtering process is expensive and complex to operate, with low metal target utilization, low production capacity and low yield, which affects the mass production of composite copper current collectors.

[0004] Therefore, in order to solve the above problems, the present invention prepares a functional current collector with high ductility, adhesion and low batch production cost. Summary of the Invention

[0005] The purpose of the present invention is to provide a functional current collector with high ductility, adhesion and low batch production cost, and a preparation method and application thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a high-ductility, high-adhesion functional current collector comprises the following steps: Step 1: Dehydrate and knead silicone rubber and white carbon black to obtain a base material; add nickel-coated graphite powder, a crosslinking agent, a coupling agent, and a catalyst to the base material and mix them evenly to obtain a conductive paste; Step 2: Coating the surface of the base layer with a conductive paste and vulcanizing it to obtain a conductive adhesive layer; this is used as a composite film; Step 3: A metal layer is plated on the surface of the composite film through a water plating process to obtain a functional current collector.

[0007] More optimally, the base layer is a polyethylene film with a thickness of 3-6 μm; the metal layer is a copper layer with a thickness of 0.5-1.5 μm; and the conductive adhesive layer is 50-100 nm.

[0008] More optimally, during the water plating process, the water plating solution includes the following components: 70-100 g / L anhydrous copper sulfate, 80-100 g / L sulfuric acid, 50-70 ppm chloride ions, 8-15 mL / L leveling agent (including but not limited to AMS-222A, sourced from Suzhou Jie Rui Mei Technology Co., Ltd.), 1-3 mL / L brightener (including but not limited to AMS-222B, sourced from Suzhou Jie Rui Mei Technology Co., Ltd.); Process parameters: temperature 20-27°C, current density 3-5A / dm 2 , voltage 1.3-1.8V, coating speed 1-3m / min.

[0009] More optimally, the raw materials of the conductive paste include the following components: by weight, 100-120 parts of silicone rubber, 25-30 parts of white carbon black, 240-250 parts of nickel-coated graphite powder, 3-15 parts of a crosslinking agent, 3-10 parts of a coupling agent, and 1-5 parts of a catalyst; The silicone rubber includes 107 silicone rubber; the crosslinking agent includes phenyltributylonoxime silane; the coupling agent includes N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; and the catalyst includes dibutyltin dilaurate.

[0010] In a further embodiment, the silicone rubber is 107 silicone rubber and vinyl polysiloxane in a mass ratio of (0.8-1):0.2; the crosslinking agent is phenyltributylanoxime silane and modified aminopropyltriethoxysilane in a mass ratio of 9:(2-4); and the catalyst is dibutyltin dilaurate and peroxide initiator in a mass ratio of 4:1.

[0011] More optimally, the preparation method of the modified aminopropyltriethoxysilane is: S1: Tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, and N,N-dimethylformamide are mixed, and phosphorus oxychloride is slowly added dropwise. After the addition is complete, the temperature is raised to 95-100°C and the reaction is maintained for 8-10 hours to obtain an aminophosphoric acid ester. In this process, triethylamine acts as an acid-binding agent to promote the forward reaction. The hydroxymethyl group in tris(hydroxymethyl)aminomethane hydrochloride reacts with phosphorus oxychloride to generate an aminophosphoric acid ester with a rigid cage-like phosphate group.

[0012] S2: Mix cardanol and anhydrous aluminum chloride, heat to 90-95°C, and add epichlorohydrin dropwise. After reacting for 2-3 hours, add sodium hydroxide solution with a concentration of 10-12wt%, continue to heat to 100-105°C, keep warm for 3-4 hours, and cool to obtain epoxidized cardanol. In this process, anhydrous aluminum chloride acts as a Lewis acid catalyst to activate the hydroxyl group of cardanol. The chlorine of epichlorohydrin reacts with the hydroxyl group of cardanol to undergo nucleophilic substitution reaction to obtain epoxidized cardanol. Since cardanol itself contains a carbon-carbon double bond, epoxidized cardanol having an epoxy group and a carbon-carbon double bond is obtained.

[0013] S3: Mix amino phosphate and epoxidized cardanol, raise the temperature to 90-100°C under a nitrogen atmosphere, and react for 2-3 hours; cool to 0°C, add formic acid and 30wt% hydrogen peroxide, and maintain for 4-5 hours to obtain a modifier; in this process, the amino group of amino phosphate and the epoxy group of epoxidized cardanol are pre-reacted and grafted; then the carbon-carbon double bond contained in the epoxidized cardanol is used to form an epoxy group under the oxidation action of formic acid and hydrogen peroxide; thereby, a modifier having a caged phosphate group and an epoxy group is obtained.

[0014] S4: Mix the modifier and aminopropyltriethoxysilane, raise the temperature to 90-100°C under a nitrogen atmosphere, maintain the temperature for 4-5 hours, and cool to room temperature to obtain modified aminopropyltriethoxysilane. During this process, the epoxy groups of the modifier react and graft with the amino groups of the aminopropyltriethoxysilane. Because the modifier contains caged phosphate groups, a modified aminopropyltriethoxysilane containing phosphate groups is obtained.

[0015] More optimally, the raw materials of the aminophosphoric acid ester include the following components: by weight, 16-18 parts of tris(hydroxymethyl)aminomethane hydrochloride, 10-12 parts of triethylamine, 50-60 parts of N,N-dimethylformamide, and 8-10 parts of phosphorus oxychloride; The raw materials of the epoxidized cardanol include the following components: 150-155 parts of cardanol, 0.15-0.2 parts of anhydrous aluminum chloride, 0.8-1 parts of epichlorohydrin, and 32-40 parts of sodium hydroxide solution in parts by weight; The raw materials of the modifier include the following components: 100-120 parts of epoxidized cardanol, 70-80 parts of amino phosphoric acid ester, 70-75 parts of formic acid, and 35-40 parts of hydrogen peroxide in parts by weight; The raw materials of the modified aminopropyltriethoxysilane include the following components: 90-100 parts of a modifier and 50-60 parts of aminopropyltriethoxysilane by weight.

[0016] More optimally, white carbon black is directly added to the conductive paste, and / or modified white carbon black is added; The preparation method of the modified silica comprises the following steps: mixing silica, toluene, and water, heating the mixture to 80-85° C., adding aminopropyltriethoxysilane dropwise, and maintaining the temperature for 20-24 hours to obtain amination silica; mixing epoxidized cardanol and amination silica, heating the mixture to 50-60° C., and reacting the mixture for 2-4 hours to obtain modified silica; in the process, the first step is to hydrolyze aminopropyltriethoxysilane and react with silica to obtain amination silica; and the second step is to react epoxidized cardanol having a carbon-carbon double bond with amination silica to obtain modified silica having a carbon-carbon double bond.

[0017] The amination silica comprises the following components: by weight, 25-30 parts of silica, 80-90 parts of toluene, 10-20 parts of water, and 7.5-8 parts of aminopropyltriethoxysilane; The raw materials of modified silica include, by weight, 40-50 parts of epoxidized cardanol and 60-70 parts of amination silica.

[0018] A functional current collector is obtained by a preparation method of a functional current collector with high ductility and adhesion.

[0019] A functional current collector is used for positive and negative electrodes in a battery.

[0020] Compared with the prior art, the present invention has the following advantages: (1) The conductive adhesive layer is set by chemical synthesis instead of sputtering the transition copper layer by magnetron sputtering equipment. The magnetron sputtering process is eliminated and expensive magnetron sputtering equipment is not required. This can greatly reduce the cost of mass production and quickly increase mass production capacity. In addition, the quality rate can be greatly improved by eliminating one step of the process.

[0021] (2) In this scheme, a composite film is formed by coating a polyethylene-based film with a conductive paste of a specific composition as a base, and then a functional current collector is formed by water plating. The mechanical properties of the polyethylene-based film and the ductility and adhesion of the conductive adhesive layer formed by the conductive paste are utilized to ensure the comprehensive performance of the functional current collector.

[0022] In the initial design, 107 silicone rubber was used as the crosslinking matrix. With the aid of the crosslinking agent phenyltributylanoxime silane and coupling agents including N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, the material was vulcanized using the catalyst dibutyltin dilaurate (vulcanization process parameters: 23±2°C for 24 hours). This formed a room-temperature crosslinked network (the primary crosslinked network), effectively ensuring crosslinking performance. The addition of silica improved the surface roughness and conductivity of the conductive adhesive layer, thereby enhancing the adsorption and bonding between the conductive adhesive layer and the polyethylene film, and between the conductive adhesive layer and the copper layer.

[0023] In a further scheme, since the 107 silicone rubber molecules are flexible chains, the intermolecular interaction force is weak, the mechanical properties are poor, and their low surface energy leads to poor bonding strength; therefore, the components of the conductive adhesive layer are further optimized; first, modified aminopropyltriethoxysilane with a caged phosphate group is introduced as a crosslinker. Since the caged phosphate group is a rigid structure, it can improve the flexible chain segment of the silicone rubber; second, vinyl polysiloxane is further introduced, and modified silica with a carbon-carbon double bond is limitedly introduced. The introduced peroxide initiator is used to produce vulcanization, and the double bonds are cross-linked to form a second cross-linked network; together with the first cross-linked network formed by 107 silicone rubber and phenyltributylanoxime silane; a three-dimensional cross-linked network is formed by the fusion of the first and second cross-linked networks, which can improve the chain entanglement and cross-linking points of the conductive adhesive layer silicone rubber, adapt to the deformation of the current collector substrate, and help form a more stable conductive adhesive layer bonding layer. In addition, since the polyethylene-based film can generate active free radicals under the initiation of a peroxide initiator, free radicals can be generated at the interface between the conductive adhesive layer and the polyethylene-based film to promote interfacial cross-linking, enhance interfacial interaction, and enhance the bonding effect, thereby enhancing the overall bonding force of the functional current collector, correspondingly increasing the elongation, and effectively improving the mechanical properties of the functional current collector.

[0024] At the same time, in a further scheme, the surface of silica is chemically modified by pre-modified silica, which effectively promotes the dispersion of silica in the conductive adhesive layer. The carbon-carbon double chains on its surface bend and wrap around the flexible chain segments of silicone rubber, effectively improving the interface effect between the silicone rubber of the conductive adhesive layer and the polyethylene base film, further improving the comprehensive performance of the conductive adhesive layer.

[0025] In summary, through the above-mentioned solution, this patent prepares a functional current collector with high ductility, adhesion and low batch production cost. DETAILED DESCRIPTION

[0026] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0027] It should be noted that the purchase manufacturers of all raw materials involved in the present invention are exemplified without any special restrictions: in the following embodiments, tris (hydroxymethyl) aminomethane hydrochloride CAS is 1185-53-1; cardanol CAS is 37330-39-5; aminopropyl triethoxysilane CAS is 919-30-2; 107 silicone rubber (ɑ, ω⁃ dihydroxy polydimethylsiloxane), viscosity is 80000 MPa s (25 ° C), industrial grade, purchased from Dow Corning Corporation of the United States; white carbon black (R947), industrial grade, purchased from Evonik Degussa Group of Germany; nickel-coated graphite powder (FIC120) mesh number is 120 mesh, industrial grade, Purchased from Guangdong Yangming Xiangxin Technology Co., Ltd.; phenyl trisbutyl ketoxime silane, content ≥90%, industrial grade, purchased from Hangzhou Guibao Chemical Co., Ltd.; coupling agent (N⁃βaminoethyl⁃γaminopropyltrimethoxysilane), content ≥98%, industrial grade, purchased from Chongyue (Guangzhou) Trading Co., Ltd.; catalyst (dibutyltin dilaurate), tin content 18.3%-18.9%, industrial grade, purchased from Jilin Huaxin Chemical Co., Ltd.; vinyl polysiloxane, viscosity 500 cSt, brand Shenzhen Jipeng; AMS-222A, sourced from Suzhou Jie Rui Mei Technology Co., Ltd., AMS-222B, sourced from Suzhou Jie Rui Mei Technology Co., Ltd.) In the following embodiments, the preparation method of modified aminopropyltriethoxysilane is: S1: Mix 16 parts of tris(hydroxymethyl)aminomethane hydrochloride, 10 parts of triethylamine, and 50 parts of N,N-dimethylformamide, slowly add 8 parts of phosphorus oxychloride dropwise, and after the addition is complete, heat to 95°C and keep the temperature for 8 hours to obtain aminophosphoric acid ester; S2: 150 parts of cardanol and 0.15 parts of anhydrous aluminum chloride were mixed, heated to 90°C, and 0.8 parts of epichlorohydrin were added dropwise. After reacting for 2 hours, 32 parts of 10 wt% sodium hydroxide solution were added dropwise. The temperature was further raised to 100°C, kept warm for 3 hours, and cooled to obtain epoxidized cardanol. S3: 70 parts of amino phosphorate and 100 parts of epoxidized cardanol were mixed, heated to 90°C under a nitrogen atmosphere, and reacted for 2 hours; cooled to 0°C, and 70 parts of formic acid and 65 parts of 30 wt% hydrogen peroxide were added, and kept for 4 hours to obtain a modifier; S4: 90 parts of the modifier and 50 parts of aminopropyltriethoxysilane were mixed, and the temperature was raised to 90° C. under a nitrogen atmosphere, maintained for 4 hours, and cooled to room temperature to obtain modified aminopropyltriethoxysilane.

[0028] Example 1: A method for preparing a high-ductility, adhesive functional current collector, comprising the following steps: Step 1: 100 parts of silicone rubber (107 silicone rubber) and 25 parts of white carbon black are put into a kneader, vacuumed and stirred evenly, and dehydrated at 120°C for 2 hours. The mixture is taken out and placed in a planetary mixer to obtain a base material; 240 parts of nickel-coated graphite powder, 3 parts of a crosslinking agent (phenyltributylanoxime silane), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane), and 4 parts of a catalyst (dibutyltin dilaurate) are added to the base material and mixed evenly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer, and a conductive paste is coated on its surface and vulcanized. The vulcanization process parameters are: placing it at 23°C for 24 hours to obtain a conductive adhesive layer; this is used as the composite film; Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0029] Example 2: Based on Example 1, the amount of crosslinking agent is 9 parts, and the rest is the same as Example 1; the details are as follows: Step 1: 100 parts of silicone rubber (107 silicone rubber) and 25 parts of white carbon black are put into a kneader, vacuumed and stirred evenly, and dehydrated at 120°C for 2 hours. The mixture is taken out and placed in a planetary mixer to obtain a base material; 240 parts of nickel-coated graphite powder, 9 parts of a crosslinking agent (phenyltributylanoxime silane), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane), and 4 parts of a catalyst (dibutyltin dilaurate) are added to the base material and mixed evenly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer, and a conductive paste is coated on its surface and vulcanized. The vulcanization process parameters are: placing it at 23°C for 24 hours to obtain a conductive adhesive layer; this is used as the composite film; Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0030] Example 3: Based on Example 1, the amount of crosslinking agent is 15 parts, and the rest is the same as Example 1; the details are as follows: Step 1: 100 parts of silicone rubber (107 silicone rubber) and 25 parts of white carbon black are put into a kneader, vacuumed and stirred evenly, and dehydrated at 120°C for 2 hours. The mixture is taken out and placed in a planetary mixer to obtain a base material; 240 parts of nickel-coated graphite powder, 15 parts of a crosslinking agent (phenyltributylanoxime silane), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane), and 4 parts of a catalyst (dibutyltin dilaurate) are added to the base material and mixed evenly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer, and a conductive paste is coated on its surface and vulcanized. The vulcanization process parameters are: placing it at 23°C for 24 hours to obtain a conductive adhesive layer; this is used as the composite film; Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0031] Example 4: Based on Example 2, a further solution is implemented, and the rest is the same as Example 1; the details are as follows: Preliminary preparation: 25 parts of silica, 80 parts of toluene, and 20 parts of water were mixed, heated to 80°C, 7.5 parts of aminopropyltriethoxysilane were added dropwise, and the mixture was kept warm for 20 hours to obtain amination silica; 40 parts of epoxidized cardanol and 60 parts of amination silica were mixed, heated to 50°C, and reacted for 5 hours to obtain modified silica; Step 1: 110 parts of silicone rubber (107 silicone rubber and vinyl polysiloxane in a mass ratio of 0.9:0.2) and modified silica are put into a kneader, vacuum-mixed and uniformly stirred, and dehydrated at 120°C for 2 hours to obtain a base material; the base material is taken out and placed in a planetary mixer, 240 parts of nickel-coated graphite powder, 12 parts of a crosslinking agent (phenyl trisbutyl ketoxime silane and modified aminopropyl triethoxysilane in a mass ratio of 9:3), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane), and 5 parts of a catalyst (4:1 dibutyltin dilaurate and peroxide initiator BPO) are added to the base material and mixed uniformly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer and irradiated at room temperature with an irradiation dose of 50 kGy. A conductive paste is then coated on the surface of the film and vulcanized. The vulcanization process parameters are: 23°C for 24 hours and heat treatment at 100°C for 1.5 hours to obtain a conductive adhesive layer. This is used as a composite film. Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0032] Example 5: Based on Example 4, the component ratios are different; specifically as follows: Preliminary preparation: 30 parts of silica, 80 parts of toluene, and 20 parts of water were mixed, heated to 80°C, 8 parts of aminopropyltriethoxysilane were added dropwise, and the mixture was kept warm for 20 hours to obtain amination silica; 40 parts of epoxidized cardanol and 60 parts of amination silica were mixed, heated to 50°C, and reacted for 5 hours to obtain modified silica; Step 1: 120 parts of silicone rubber (107 silicone rubber and vinyl polysiloxane in a mass ratio of 1:0.2) and modified silica are put into a kneader, vacuum-mixed and uniformly stirred, and dehydrated at 120°C for 2 hours to obtain a base material; the base material is taken out and placed in a planetary mixer, 250 parts of nickel-coated graphite powder, 13 parts of a crosslinking agent (phenyl trisbutyl ketoxime silane and modified aminopropyl triethoxysilane in a mass ratio of 9:4), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane), and 5 parts of a catalyst (4:1 dibutyltin dilaurate and peroxide initiator BPO) are added to the base material and mixed uniformly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as a base layer and irradiated at room temperature with an irradiation dose of 50 kGy. A conductive paste is coated on the surface of the film and vulcanized. The vulcanization process parameters are: 23°C for 24 hours and heat treatment at 110°C for 2 hours to obtain a conductive adhesive layer. This is used as a composite film. Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0033] Example 6: Based on Example 4, the component ratios are different; specifically as follows: Preliminary preparation: 28 parts of silica, 80 parts of toluene, and 20 parts of water were mixed, heated to 80°C, 7.5 parts of aminopropyltriethoxysilane were added dropwise, and the mixture was kept warm for 20 hours to obtain amination silica; 40 parts of epoxidized cardanol and 60 parts of amination silica were mixed, heated to 50°C, and reacted for 5 hours to obtain modified silica; Step 1: 100 parts of silicone rubber (107 silicone rubber and vinyl polysiloxane in a mass ratio of 0.8:0.2) and modified silica are put into a kneader, vacuum-mixed and uniformly stirred, and dehydrated at 120°C for 2 hours to obtain a base material; the base material is taken out and placed in a planetary mixer, 240 parts of nickel-coated graphite powder, 13 parts of a crosslinking agent (phenyl trisbutyl ketoxime silane and modified aminopropyl triethoxysilane in a mass ratio of 9:4), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane), and 5 parts of a catalyst (4:1 dibutyltin dilaurate and peroxide initiator BPO) are added to the base material and mixed uniformly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as a base layer and irradiated at room temperature with an irradiation dose of 50 kGy. A conductive paste is coated on the surface of the film and vulcanized. The vulcanization process parameters are: placing at 23°C for 24 hours and heat treating at 110°C for 1.5 hours to obtain a conductive adhesive layer. This is used as a composite film. Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0034] Comparative Example 1: Based on Example 1, the base film material is PP, and the rest is the same as Example 1; Comparative Example 2: Based on Example 1, the conductive adhesive layer was not coated, and a copper layer was plated using magnetron sputtering. The target material was a target material of the metal layer material (purity>99.9%), the target power was 7kW, the vacuum degree was 0.1Pa, the gas source was argon, the argon flow rate was 250m / min, and the coating time was 15s; water plating pretreatment was performed; Comparative Example 3: Based on Example 4, amino-treated silica was used instead of modified silica; the details are as follows: Pre-preparation: Mix 25 parts of silica, 80 parts of toluene, and 20 parts of water, heat to 80°C, add 7.5 parts of aminopropyltriethoxysilane dropwise, and keep warm for 20 hours to obtain amination silica; Step 1: 100 parts of silicone rubber (107 silicone rubber and vinyl polysiloxane in a mass ratio of 0.8:0.2) and amino-treated silica are put into a kneader, vacuum-mixed and uniformly stirred, and dehydrated at 120°C for 2 hours to obtain a base material; the base material is taken out and placed in a planetary mixer, 250 parts of nickel-coated graphite powder, 13 parts of a crosslinking agent (phenyl trisbutyl ketoxime silane and modified aminopropyl triethoxysilane in a mass ratio of 10:3), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane), and 5 parts of a catalyst (4:1 dibutyltin dilaurate and peroxide initiator BPO) are added to the base material and mixed evenly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer and irradiated at room temperature with an irradiation dose of 50 kGy. A conductive paste is then coated on the surface of the film and vulcanized. The vulcanization process parameters are: 23°C for 24 hours and heat treatment at 100°C for 1.5 hours to obtain a conductive adhesive layer. This is used as a composite film. Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0035] Comparative Example 4: Based on Example 4, aminopropyltriethoxysilane was used instead of modified aminopropyltriethoxysilane; the details are as follows: Preliminary preparation: 25 parts of silica, 80 parts of toluene, and 20 parts of water were mixed, heated to 80°C, 7.5 parts of aminopropyltriethoxysilane were added dropwise, and the mixture was kept warm for 20 hours to obtain amination silica; 40 parts of epoxidized cardanol and 60 parts of amination silica were mixed, heated to 50°C, and reacted for 5 hours to obtain modified silica; Step 1: 100 parts of silicone rubber (107 silicone rubber and vinyl polysiloxane in a mass ratio of 0.8:0.2) and modified silica are put into a kneader, vacuum-mixed and uniformly stirred, and dehydrated at 120°C for 2 hours to obtain a base material; the base material is taken out and placed in a planetary mixer, 250 parts of nickel-coated graphite powder, 13 parts of a crosslinking agent (phenyl trisbutyl ketoxime silane and aminopropyl triethoxysilane in a mass ratio of 10:3), 4 parts of a coupling agent (N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane), and 5 parts of a catalyst (4:1 dibutyltin dilaurate and peroxide initiator BPO) are added to the base material and mixed uniformly to obtain a conductive paste; Step 2: A polyethylene film with a thickness of 4.5 μm is used as the base layer and irradiated at room temperature with an irradiation dose of 50 kGy. A conductive paste is then coated on the surface of the film and vulcanized. The vulcanization process parameters are: 23°C for 24 hours and heat treatment at 100°C for 1.5 hours to obtain a conductive adhesive layer. This is used as a composite film. Step 3: Copper metal is plated on the surface of the composite film by water plating. During the water plating process, the water plating solution includes the following components: 80g / L anhydrous copper sulfate, 80g / L sulfuric acid, 60ppm chloride ion, 10mL / L leveler AMS-222A, 2mL / L brightener AMS-222B; the water plating process is: temperature 25℃, current density 4A / dm 2 , voltage 1.5V, and coating speed 2m / min to obtain a functional current collector.

[0036] Performance test: The functional current collectors prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to the following tests: (1) Elongation test: According to the standard of GB / T 1040.3-2006, samples were taken from the functional copper current collector in the transverse direction and the elongation test was performed; (2) Adhesion test: A layer of Permacel P-94 double-sided tape was adhered to a 1 mm thick aluminum foil, the functional current collector was adhered on the double-sided tape, and a layer of ethylene acrylic acid copolymer film (DuPont Nurcel0903, thickness of 50 μm) was covered on the functional current collector. Then, the functional current collector was placed on a 1.3×10 5 N / m 2 The film was hot-pressed at 120°C for 10 seconds, cooled to room temperature, and cut into 150mm x 15mm strips. The ethylene acrylic acid copolymer film strip was fixed to the upper fixture of the tensile testing machine, and the remaining film strip was fixed to the lower fixture. After being fixed, the two strips were peeled off at an angle of 180° and a speed of 100mm / min to test the adhesion.

[0037] The results are shown in the following table:

[0038] Conclusion: By modifying the substrate material and the conductive adhesive coating method, this method improves the ductility and adhesion of the functional current collector. Compared to Comparative Example 2, this method eliminates the magnetron sputtering step and directly performs water electroplating, reducing the manufacturing cost of the functional current collector. This reduced step significantly improves the yield. Furthermore, by optimizing the conductive adhesive layer, the overall performance of the functional current collector is effectively improved.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a functional current collector with high ductility and adhesion, characterized by: The following steps are involved: Step 1: Dehydrate and knead silicone rubber and white carbon black to obtain a base material; Adding nickel-coated graphite powder, a crosslinking agent, a coupling agent, and a catalyst into a base material and mixing them uniformly to obtain a conductive paste; Step 2: Coating the surface of the base layer with a conductive paste and vulcanizing it to obtain a conductive adhesive layer; this is used as a composite film; Step 3: A metal layer is plated on the surface of the composite film through a water plating process to obtain a functional current collector.

2. The method for preparing a high-ductility, high-adhesion functional current collector according to claim 1, characterized in that: The base layer is a polyethylene film with a thickness of 3-6 μm; the metal layer is a copper layer with a thickness of 0.5-1.5 μm; and the conductive adhesive layer is 50-100 nm.

3. The method for preparing a high-ductility, high-adhesion functional current collector according to claim 1, characterized in that: During the water plating process, the water plating solution includes the following components: 70-100 g / L anhydrous copper sulfate, 80-100 g / L sulfuric acid, 50-70 ppm chloride ions, 8-15 mL / L leveling agent, and 1-3 mL / L brightener; Process parameters: temperature 20-27°C, current density 3-5A / dm 2 , voltage 1.3-1.8V, coating speed 1-3m / min.

4. The method for preparing a high-ductility, high-adhesion functional current collector according to claim 1, characterized in that: The raw materials of the conductive paste include the following components: by weight, 100-120 parts of silicone rubber, 25-30 parts of white carbon black, 240-250 parts of nickel-coated graphite powder, 3-15 parts of a crosslinking agent, 3-10 parts of a coupling agent, and 1-5 parts of a catalyst; The silicone rubber includes 107 silicone rubber; the crosslinking agent includes phenyltributylonoxime silane; the coupling agent includes N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; and the catalyst includes dibutyltin dilaurate.

5. The method for preparing a functional current collector with high ductility and adhesion according to claim 4, characterized in that: The silicone rubber is 107 silicone rubber and vinyl polysiloxane in a mass ratio of (0.8-1):0.2; the crosslinking agent is phenyl tributyl ketoxime silane and modified aminopropyl triethoxysilane in a mass ratio of 9:(2-4); and the catalyst is dibutyltin dilaurate and peroxide initiator in a mass ratio of 4:

1.

6. The method for preparing a high-ductility, high-adhesion functional current collector according to claim 5, characterized in that: The preparation method of the modified aminopropyltriethoxysilane is: S1: Mix tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, and N,N-dimethylformamide, slowly add phosphorus oxychloride dropwise, and after the addition is complete, heat to 95-100°C and keep the temperature to react for 8-10 hours to obtain aminophosphoric acid ester; S2: Mix cardanol and anhydrous aluminum chloride, heat to 90-95°C, and dropwise add epichlorohydrin. After reacting for 2-3 hours, dropwise add a 10-12 wt% sodium hydroxide solution, continue heating to 100-105°C, keep warm for 3-4 hours, and cool to obtain epoxidized cardanol; S3: mixing aminophosphoric acid ester and epoxidized cardanol, heating to 90-100°C under nitrogen atmosphere, reacting for 2-3 hours; cooling to 0°C, adding formic acid and 30 wt% hydrogen peroxide, maintaining for 4-5 hours, to obtain a modifier; S4: Mix the modifier and aminopropyltriethoxysilane, raise the temperature to 90-100° C. under a nitrogen atmosphere, maintain the temperature for 4-5 hours, and cool to room temperature to obtain modified aminopropyltriethoxysilane.

7. The method for preparing a functional current collector with high ductility and adhesion according to claim 6, characterized in that: The raw materials of the aminophosphoric acid ester include the following components: 16-18 parts of tris(hydroxymethyl)aminomethane hydrochloride, 10-12 parts of triethylamine, 50-60 parts of N,N-dimethylformamide, and 8-10 parts of phosphorus oxychloride, by weight; The raw materials of the epoxidized cardanol include the following components: 150-155 parts of cardanol, 0.15-0.2 parts of anhydrous aluminum chloride, 0.8-1 parts of epichlorohydrin, and 32-40 parts of sodium hydroxide solution in parts by weight; The raw materials of the modifier include the following components: 100-120 parts of epoxidized cardanol, 70-80 parts of amino phosphoric acid ester, 70-75 parts of formic acid, and 35-40 parts of hydrogen peroxide in parts by weight; The raw materials of the modified aminopropyltriethoxysilane include the following components: 90-100 parts of a modifier and 50-60 parts of aminopropyltriethoxysilane by weight.

8. The method for preparing a functional current collector with high ductility and adhesion according to claim 4, characterized in that: Directly adding silica and / or modified silica to the conductive paste; The modified silica preparation method comprises: mixing silica, toluene, and water, heating the mixture to 80-85° C., adding aminopropyltriethoxysilane dropwise, and maintaining the temperature for 20-24 hours to obtain amination silica; mixing epoxidized cardanol and amination silica, heating the mixture to 50-60° C., and reacting the mixture for 2-4 hours to obtain modified silica; The amination silica comprises the following components: by weight, 25-30 parts of silica, 80-90 parts of toluene, 10-20 parts of water, and 7.5-8 parts of aminopropyltriethoxysilane; The raw materials of modified silica include, by weight, 40-50 parts of epoxidized cardanol and 60-70 parts of amination silica.

9. A functional current collector obtained by the method for preparing a functional current collector with high ductility and adhesion according to any one of claims 1 to 8.

10. Application of a high ductility and adhesive functional current collector, characterized by: The functional current collector according to any one of claims 1 to 9 is applied to the positive and negative electrodes in a battery.

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