CN115241406A - Conductive slurry for aluminum foil surface of lithium battery positive current collector and preparation method and application thereof - Google Patents
Conductive slurry for aluminum foil surface of lithium battery positive current collector and preparation method and application thereof Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention relates to a conductive slurry for the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, and a preparation method and application thereof. The conductive slurry is used for coating and curing the surface of the aluminum foil to form a carbon coating layer; the conductive paste comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
Description
Technical Field
The invention relates to the technical field of lithium battery materials, in particular to a lithium battery positive current collector aluminum foil surface conductive slurry and a preparation method and application thereof.
Background
Lithium batteries are chemical batteries which achieve the purpose of charging and discharging by shuttling lithium ions between a positive electrode and a negative electrode. The lithium ion battery has the advantages of high energy density, high working voltage, long cycle life, large charge-discharge multiplying power and the like, so that the lithium ion battery is widely applied to the fields of new energy automobiles, 3C products and energy storage batteries. The main materials of the lithium battery comprise a positive electrode material, a negative electrode material, electrolyte and a diaphragm. Besides the main four parts, the current collectors of the positive electrode and the negative electrode are also important components of the lithium battery. For lithium ion batteries, the positive current collector typically used is aluminum foil and the negative current collector is copper foil.
Generally, in the lithium ion battery industry, rolled aluminum foil is used as a positive electrode current collector, and the current collector plays an important role in improving the charging and discharging efficiency of a lithium battery. The surface of the aluminum foil is coated with the conductive slurry, so that the polarization of the battery can be inhibited, the heat effect is reduced, the multiplying power performance of the battery is improved, meanwhile, the adhesion of an active substance and the aluminum foil can be improved, and the using amount of a binder is reduced. The carbon-coated aluminum foil is one of the aluminum foils commonly used in the industry, but the carbon-coated aluminum foil has the problems of poor adhesion and easy peeling of the carbon-coated layer, and the increase of the content of the binder in the conductive paste for improving the adhesion can reduce the conductivity of the carbon-coated layer.
In order to solve the problems, the Chinese invention patent CN107507981B discloses a carbon-coated current collector containing polydopamine, wherein the coating contains polydopamine and graphene, the scheme mainly aims at the problem that a large amount of heat generated in the battery cannot be dissipated quickly under the condition of high-current charging and discharging, and the good heat conduction characteristics of the polydopamine and the graphene are utilized to coat a composite coating of the graphene and the polydopamine on the surface of the current collector, so that the bonding strength of the current collector and an active substance is further improved, and meanwhile, the effect of reducing the internal temperature of the battery is achieved. However, in the invention, the improvement of the adhesion between the carbon coating layer and the positive electrode active material is not obvious, and the improvement of the conductivity of the carbon-coated aluminum foil is not obviously helped. Moreover, the price of the graphene is far higher than that of the conductive carbon black, and the price factor is not beneficial to industrial implementation.
Meanwhile, the invention patent CN104538638B in china mentions a lithium ion battery positive aluminum foil conductive agent, which aims to solve the technical problems of dynamic internal resistance amplification, pole piece tolerance and the like of a battery, improve gram capacity, power performance and pressure difference consistency of a battery pack, improve electrical contact between an active material and an aluminum foil current collector, reduce polarization and reduce manufacturing cost of a lithium ion battery pole piece. However, the preparation method of the present invention takes a long time, and the obtained conductive paste has a large particle size and poor dispersion stability, and it is difficult to improve the performance of a lithium battery to a large extent.
In conclusion, the conductive paste for coating the surface of the aluminum foil of the positive current collector for the lithium battery, which has the advantages of good conductivity, high heat dissipation performance, strong corrosion resistance and good binding power, can effectively improve the low-temperature discharge capacity of the lithium battery and prolong the cycle life, has wide market application value and prospect, and can effectively promote the further development of the lithium battery industry.
Disclosure of Invention
The embodiment of the invention provides conductive slurry for the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, and a preparation method and application thereof. The conductive slurry on the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery can be used for inhibiting battery polarization, reducing the heat effect and improving the multiplying power performance of the battery, and meanwhile, the adhesion of an active substance and the aluminum foil can be improved, the using amount of a binder is reduced, and the improvement of the conductivity of the battery is facilitated.
In a first aspect, an embodiment of the present invention provides a conductive paste for a surface of an aluminum foil of a positive current collector of a lithium battery, where the conductive paste is used to coat and cure the surface of the aluminum foil to form a carbon coating;
the conductive paste comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
Preferably, the conductive agent includes: conductive carbon black with primary particle size D50 of 30-60nm;
the dispersant comprises: polyvinylpyrrolidone or hydrophilic acrylic hyperbranched block copolymers; wherein the molecular formula of the polyvinylpyrrolidone is (C) 6 H 9 NO) n N is the average number of 1-vinyl-2-pyrrolidone mer, said polyvinylpyrrolidoneHas an average molecular weight of 10,000 to 1,600,000;
the second solvent includes: one or more of ethanol, isopropanol, N-dimethylformamide, ethyl acetate, dibutyl phthalate or other hydrophilic polar solvents;
the pH regulator comprises: one or more of alkanolamine pH regulator, ammonia water, sodium hydroxide, calcium hydroxide, potassium hydroxide or sodium citrate;
the leveling agent comprises: one or more of acrylic acid copolymer, fluorine modified acrylate, phosphate modified acrylate, alkylphenol polyoxyethylene, polyamine ethylene oxide condensate or nonionic polyethylene glycol ester;
the adhesive comprises: one or more of polyacrylate type binder, SBR type binder, polyacrylonitrile type binder or other resin type binder.
In a second aspect, an embodiment of the present invention provides a method for preparing a conductive paste for an aluminum foil surface of a positive current collector of a lithium battery, where the method includes:
step 1, dispersing a dispersant in water to form a dispersant aqueous solution, and standing;
step 2, mixing and dispersing water, the standing dispersant aqueous solution, sodium carboxymethyl cellulose and a second solvent to obtain a first mixed solution;
step 3, adding a conductive agent into the first mixed solution in multiple times, and continuously mixing and dispersing to obtain a second mixed solution;
step 4, adding a pH regulator, a flatting agent, a binder and a silane coupling agent into the second mixed solution, and mixing and dispersing to obtain the conductive slurry; the conductive paste comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
Preferably, the dispersion or mixed dispersion is specifically: dispersing by using any one of a refiner, a high-speed disperser, an ultrasonic disperser, a high-pressure homogenizer and a sand mill.
Preferably, the dispersing or mixing dispersing method in the steps 1 to 3 specifically comprises: dispersing by adopting a high-speed dispersion machine, wherein the linear speed is 7-15 m/s; wherein the mixing and dispersing time is 5-30 minutes.
Preferably, the mixing and dispersing method in the step 4 specifically comprises the following steps: two or three of an ultrasonic disperser, a high-pressure homogenizer and a sand mill are adopted for dispersing in sequence; wherein the mixing and dispersing time is 5-40 minutes.
Preferably, the conductive agent includes: conductive carbon black with primary particle size D50 of 30-60nm;
the dispersant comprises: polyvinylpyrrolidone or hydrophilic acrylic hyperbranched block copolymers; wherein the molecular formula of the polyvinylpyrrolidone is (C) 6 H 9 NO) n N is the average number of 1-vinyl-2-pyrrolidone mer, the average molecular weight of the polyvinylpyrrolidone is between 10,000 and 1,600,000;
the second solvent includes: one or more of ethanol, isopropanol, N-dimethylformamide, ethyl acetate, dibutyl phthalate or other hydrophilic polar solvents;
the pH regulator comprises: one or more of alkanolamine pH regulator, ammonia water, sodium hydroxide, calcium hydroxide, potassium hydroxide or sodium citrate;
the leveling agent comprises: one or more of acrylic copolymer, fluorine modified acrylate, phosphate modified acrylate, alkylphenol polyoxyethylene, polyamine ethylene oxide condensate or nonionic polyethylene glycol ester;
the adhesive comprises: one or more of polyacrylate type binder, styrene butadiene latex SBR type binder, polyacrylonitrile type binder or other resin type binder.
In a third aspect, the embodiment of the invention provides a positive electrode current collector of a lithium battery, which comprises an aluminum foil substrate and a carbon coating layer; the carbon coating layer is obtained by drying the conductive slurry for the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery in the first aspect.
In a fourth aspect, embodiments of the present invention provide a positive electrode of a lithium battery, including the positive electrode current collector of the lithium battery described in the third aspect.
In a fifth aspect, an embodiment of the present invention provides a lithium battery including the lithium battery positive electrode described in the fourth aspect.
According to the conductive slurry on the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery, which is provided by the embodiment of the invention, the uniformly dispersed carbon black is used as a framework structure, so that the polarization of the battery can be effectively inhibited, the heat effect is reduced, and the rate capability of the battery is improved; the processing stability of the slurry is improved and the coating construction difficulty is reduced by using the second solvent; the sodium carboxymethyl cellulose is matched with the dispersing agent for use, so that the dispersing effect is enhanced, the viscosity of the slurry is adjusted, and the subsequent coating is facilitated; the pH regulator is compounded with the binder to enhance the binding power and improve the dispersion stability of the slurry; the adhesive force between the aluminum foil substrate and the slurry is enhanced by adding a silane coupling agent as a framework material. The carbon-coated layer formed by curing the conductive paste after coating can improve the adhesion of the active substance and the aluminum foil, and is beneficial to reducing the using amount of the adhesive.
Drawings
The technical solutions of the embodiments of the present invention are further described in detail with reference to the accompanying drawings and embodiments.
Fig. 1 is a flowchart of a method for preparing a conductive paste on an aluminum foil surface of a current collector of a positive electrode of a lithium battery according to an embodiment of the present invention.
Detailed Description
The invention is further illustrated by the following figures and specific examples, but it should be understood that these examples are for the purpose of illustration only and are not to be construed as in any way limiting the present invention, i.e., as in no way limiting its scope.
The invention relates to conductive slurry for the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, which is used for coating and curing the surface of the aluminum foil to form a carbon coating and comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
The conductive agent includes: conductive carbon black, preferably having a primary particle size D50 of 30 to 60nm;
the dispersant comprises: polyvinylpyrrolidone or hydrophilic acrylic hyperbranched block copolymers; wherein the molecular formula of the polyvinylpyrrolidone is (C) 6 H 9 NO) n N is the average number of 1-vinyl-2-pyrrolidone mer, the average molecular weight of the polyvinylpyrrolidone is between 10,000 and 1,600,000, specifications include but are not limited to K15, K30, K60, K90, preferably K30; the hydrophilic acrylic hyperbranched segmented copolymer is a finished product dispersant, and the brand types of the hydrophilic acrylic hyperbranched segmented copolymer include but are not limited to BYK LP N21954, WP2021, WSGK05A, ADS-20 and the like.
The molecular weight of the sodium carboxymethylcellulose is 2000-20000; the dispersant is matched for use to enhance the dispersion effect and adjust the viscosity of the slurry, thereby facilitating the subsequent coating.
The second solvent includes: one or more of ethanol, isopropanol, N-dimethylformamide, ethyl acetate, dibutyl phthalate or other hydrophilic polar solvents are mixed; the processing stability of the slurry is improved through the second solvent, and the coating construction difficulty is reduced.
The adhesive comprises: one or more of polyacrylate type binder, styrene butadiene latex SBR type binder, polyacrylonitrile type binder or other resin type binder.
The pH regulator comprises: one or more of alkanolamine pH regulator, ammonia water, sodium hydroxide, calcium hydroxide, potassium hydroxide or sodium citrate; the pH regulator is compounded with the binder for use, so that the binding power is enhanced, and the dispersion stability of the slurry is improved.
The leveling agent comprises: one or more of acrylic copolymer, fluorine modified acrylate, phosphate modified acrylate, alkylphenol polyoxyethylene, polyamine ethylene oxide condensate or nonionic polyethylene glycol ester;
the silane coupling agent is a finished product, and the type of the silane coupling agent comprises one or a mixture of more of A-150, A-151, A-171, A-172, A-187, A-174, A-1891, A-189, A-1100, A-1120, KH-550, KH-560, KH-570, KH-580, KH-590, KH-902, KH-792 and KH-903, and can be used as a framework material to enhance the adhesive force between the aluminum foil base material and the slurry.
The conductive slurry on the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery provided by the embodiment of the invention can be prepared by the preparation method shown in figure 1. The method specifically comprises the following steps:
the standing time is preferably 24 hours.
and 140, adding the pH regulator, the flatting agent, the binder and the silane coupling agent into the second mixed solution, mixing and dispersing to obtain the conductive slurry.
The dispersion or mixing dispersion in the steps is specifically as follows: dispersing by using any one of a refiner, a high-speed disperser, an ultrasonic disperser, a high-pressure homogenizer and a sand mill.
The preferable scheme is that the dispersing or mixing dispersing method in the steps 1 to 3 specifically adopts a high-speed dispersing machine to disperse, and the linear speed is 7m/s-15m/s; the mixing and dispersing time is 5-30 minutes. The mixing and dispersing method in the step 4 specifically adopts two or three of an ultrasonic disperser, a high-pressure homogenizer and a sand mill to disperse in sequence; the mixing and dispersing time is 5-40 minutes. The purposes of uniform dispersion and concentrated particle size distribution of the carbon black are achieved by mixing and dispersing in various modes in the last step.
Further, the high-pressure homogenizer is preferably one of a cavitation nozzle type, a collision valve type, and a Y-type alternating high-pressure homogenizer. The pressure is controlled at 20-120Mpa, and the cycle times are 1-5 times. The zirconium beads used for the sand mill dispersion are preferably 0.1mm to 0.8mm to obtain a smaller particle size of the carbon black.
The conductive paste prepared by the invention is coated on an aluminum foil matrix of a lithium battery positive current collector, and the aluminum foil with a carbon coating layer, namely the carbon-coated aluminum foil, is obtained after drying and is used as a positive current collector.
The positive electrode current collector of the lithium battery can be used for the lithium battery, and particularly used in the positive electrode of the lithium battery.
In order to better understand the technical solutions provided by the present invention, the following description will respectively illustrate the preparation of conductive paste and the characteristics thereof by using the methods provided by the above embodiments of the present invention.
Example 1
The embodiment provides a preparation method of conductive slurry on the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, wherein the conductive slurry comprises the following components in parts by mass: 64 parts of water, 10 parts of conductive carbon black, 1 part of polyvinylpyrrolidone, 0.2 part of sodium carboxymethylcellulose, 20 parts of ethanol, 0.5 part of alkanolamine, 0.1 part of alkylphenol polyoxyethylene, 4 parts of polyacrylic acid binder and 0.2 part of silane coupling agent KH 560.
The polyvinylpyrrolidone used as a dispersant of the conductive paste has an average molecular weight of 40000.
The conductive agent carbon black used has a particle size D50 of 45nm.
The dispersion mode is that firstly polyvinylpyrrolidone is dispersed in water to form dispersant aqueous solution, after standing, the dispersant aqueous solution is mixed and dispersed with water, sodium carboxymethyl cellulose and ethanol through a high-speed homogenizer, then conductive carbon black is added for three times and dispersed through a high-pressure homogenizer, and finally alkanolamine, alkylphenol ethoxylate, polyacrylic acid binder and silane coupling agent KH560 are added for dispersion and sanding through the high-pressure homogenizer to obtain conductive slurry.
And coating the conductive slurry on the surface of the aluminum foil, curing to form a carbon coating layer with the dry film thickness of 2 mu m, and preparing a current collector sheet for electrical property test.
Example 2
The embodiment provides a preparation method of conductive slurry on the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, which is basically the same as that in the embodiment 1, except that the average molecular weight of polyvinylpyrrolidone used as a dispersing agent of the conductive slurry is 360000.
Example 3
This example provides a method for preparing conductive paste on the surface of aluminum foil of the current collector of the positive electrode of a lithium battery, which is substantially the same as that in example 1, except that the dry film thickness is 10um.
Example 4
The embodiment provides a preparation method of conductive slurry on the surface of an aluminum foil of a current collector of a positive electrode of a lithium battery, which is basically the same as that in the embodiment 1, except that after a dispersant aqueous solution is stood still, the dispersant aqueous solution is mixed and dispersed with water, sodium carboxymethyl cellulose and ethanol through a high-speed refiner, then conductive carbon black is added for three times and is continuously dispersed through the high-speed refiner to obtain primary dispersed slurry, the obtained primary dispersed slurry is subjected to sanding, and finally alkanolamine, alkylphenol ethoxylates, polyacrylic acid binder and silane coupling agent KH560 are added and mixed through the high-speed refiner to obtain the conductive slurry.
And coating the conductive slurry on the surface of the aluminum foil, curing to form a carbon-coated layer with the dry film thickness of 2um, and preparing a current collector sheet for electrical property test.
The above examples were tested and compared to a blank control aluminum foil, and the results are shown in table 1.
TABLE 1
As can be seen from the comparison in Table 1, the application of the conductive paste effectively increases the adhesion of the pole piece coating roll compared to the smooth foil.
As can be seen from the comparison in Table 1, the coating of the conductive paste provided by the invention on the surface of the aluminum foil effectively reduces the resistance of the pole piece, increases the conductivity of the pole piece, and finally can reduce the internal resistance of the complete battery, thereby reducing the heating efficiency of the lithium battery and improving the service cycle life of the lithium battery.
The conductive paste prepared in each example was centrifuged and sedimented at a centrifuge speed of 4000rpm, and the dispersion stability was determined by measuring the viscosity of the conductive paste using the upper and lower liquids, and the results are shown in table 2.
TABLE 2
As can be seen from comparison in table 2, the use of the homogenizer for dispersion can effectively increase the dispersion uniformity and stability, thereby improving the overall performance of the battery.
According to the conductive slurry on the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery, which is provided by the embodiment of the invention, the uniformly dispersed carbon black is used as a framework structure, so that the polarization of the battery can be effectively inhibited, the heat effect is reduced, and the rate capability of the battery is improved; the processing stability of the slurry is improved and the coating construction difficulty is reduced by using the second solvent; the sodium carboxymethyl cellulose is matched with the dispersing agent for use, so that the dispersing effect is enhanced, the viscosity of the slurry is adjusted, and the subsequent coating is facilitated; the pH regulator is compounded with the binder to enhance the binding power and improve the dispersion stability of the slurry; the adhesive force between the aluminum foil substrate and the slurry is enhanced by adding a silane coupling agent as a framework material. The carbon-coated layer formed by curing the conductive paste after coating can improve the adhesion of the active substance and the aluminum foil, and is beneficial to reducing the using amount of the adhesive.
The preparation method is simple, the used equipment and conditions are easy to obtain, the conductive carbon black is used as the main raw material, the cost is low, the preparation period is short, the preparation efficiency is high, the preparation method is suitable for expanding batch production, and the preparation method has positive practical significance for the development of lithium batteries.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The conductive slurry for the surface of the aluminum foil of the current collector of the positive electrode of the lithium battery is characterized in that the conductive slurry is used for coating and curing the surface of the aluminum foil to form a carbon coating layer;
the conductive paste comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
2. The conductive paste according to claim 1,
the conductive agent includes: conductive carbon black with primary particle size D50 of 30-60nm;
the dispersant comprises: polyvinylpyrrolidone or hydrophilic acrylic hyperbranched block copolymers; wherein the molecular formula of the polyvinylpyrrolidone is (C) 6 H 9 NO) n N is the average number of 1-vinyl-2-pyrrolidone mer, the polyvinylpyrrolidone has an average molecular weight of between 10,000 and 1,600,000;
the second solvent includes: one or more of ethanol, isopropanol, N-dimethylformamide, ethyl acetate, dibutyl phthalate or other hydrophilic polar solvents;
the pH regulator comprises: one or more of alkanolamine pH regulator, ammonia water, sodium hydroxide, calcium hydroxide, potassium hydroxide or sodium citrate;
the leveling agent comprises: one or more of acrylic acid copolymer, fluorine modified acrylate, phosphate modified acrylate, alkylphenol polyoxyethylene, polyamine ethylene oxide condensate or nonionic polyethylene glycol ester;
the adhesive comprises: one or more of polyacrylate type binder, styrene butadiene latex SBR type binder, polyacrylonitrile type binder or other resin type binder.
3. A method for preparing the conductive paste for the aluminum foil surface of the positive electrode current collector of the lithium battery as set forth in any one of claims 1 or 2, wherein the method comprises:
step 1, dispersing a dispersant in water to form a dispersant aqueous solution, and standing;
step 2, mixing and dispersing water, the standing dispersant aqueous solution, sodium carboxymethyl cellulose and a second solvent to obtain a first mixed solution;
step 3, adding a conductive agent into the first mixed solution in multiple times, and continuously mixing and dispersing to obtain a second mixed solution;
step 4, adding a pH regulator, a leveling agent, a binder and a silane coupling agent into the second mixed solution, mixing and dispersing to obtain the conductive slurry; the conductive paste comprises the following components in percentage by mass: 38-91 parts of water, 1-15 parts of conductive agent, 1-10 parts of dispersing agent, 0.1-0.2 part of sodium carboxymethylcellulose, 1-37 parts of second solvent, 0.1-0.5 part of pH regulator, 0.1-0.3 part of flatting agent, 4-8 parts of binder and 0.1-0.5 part of silane coupling agent.
4. The method according to claim 3, characterized in that the dispersion or mixed dispersion is in particular: dispersing by using any one of a refiner, a high-speed disperser, an ultrasonic disperser, a high-pressure homogenizer and a sand mill.
5. The method according to claim 4, wherein the dispersing or mixing and dispersing method in the steps 1 to 3 is specifically: dispersing by adopting a high-speed dispersion machine, wherein the linear speed is 7-15 m/s; wherein the mixing and dispersing time is 5-30 minutes.
6. The preparation method according to claim 4, wherein the mixing and dispersing method in the step 4 is specifically: two or three of an ultrasonic disperser, a high-pressure homogenizer and a sand mill are adopted for dispersing in sequence; wherein the mixing and dispersing time is 5-40 minutes.
7. The method according to claim 3,
the conductive agent includes: conductive carbon black with primary particle size D50 of 30-60nm;
the dispersant comprises: polyvinylpyrrolidone or hydrophilic acrylic hyperbranched block copolymers; wherein the molecular formula of the polyvinylpyrrolidone is (C) 6 H 9 NO) n N is the average number of 1-vinyl-2-pyrrolidone mer, the average molecular weight of the polyvinylpyrrolidone is between 10,000 and 1,600,000;
the second solvent includes: one or more of ethanol, isopropanol, N-dimethylformamide, ethyl acetate, dibutyl phthalate or other hydrophilic polar solvents;
the pH regulator comprises: one or more of alkanolamine pH regulator, ammonia water, sodium hydroxide, calcium hydroxide, potassium hydroxide or sodium citrate;
the leveling agent comprises: one or more of acrylic acid copolymer, fluorine modified acrylate, phosphate modified acrylate, alkylphenol polyoxyethylene, polyamine ethylene oxide condensate or nonionic polyethylene glycol ester;
the adhesive comprises: one or more of polyacrylate type binder, styrene butadiene latex SBR type binder, polyacrylonitrile type binder or other resin type binder.
8. The positive current collector of the lithium battery is characterized by comprising an aluminum foil matrix and a carbon coating layer; the carbon coating layer is obtained by drying the conductive slurry for the surface of the aluminum foil of the positive electrode current collector of the lithium battery in any one of the claims 1-2.
9. A positive electrode for a lithium battery comprising the positive electrode current collector for a lithium battery as claimed in claim 8.
10. A lithium battery comprising the positive electrode for a lithium battery as claimed in claim 9.
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| CN202210890456.4A Pending CN115241406A (en) | 2022-07-27 | 2022-07-27 | Conductive slurry for aluminum foil surface of lithium battery positive current collector and preparation method and application thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116462792A (en) * | 2023-06-19 | 2023-07-21 | 广州纳诺新材料技术有限公司 | Lithium battery carbon-coated foil conductive slurry, modified acrylic composite resin emulsion and preparation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116462792A (en) * | 2023-06-19 | 2023-07-21 | 广州纳诺新材料技术有限公司 | Lithium battery carbon-coated foil conductive slurry, modified acrylic composite resin emulsion and preparation method thereof |
| CN116462792B (en) * | 2023-06-19 | 2023-09-01 | 广州纳诺新材料技术有限公司 | Lithium battery carbon-coated foil conductive slurry, modified acrylic composite resin emulsion and preparation method thereof |
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