CN115275523A - Diaphragm for polyvinyl lithium battery and preparation method thereof - Google Patents

Diaphragm for polyvinyl lithium battery and preparation method thereof Download PDF

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CN115275523A
CN115275523A CN202210774292.9A CN202210774292A CN115275523A CN 115275523 A CN115275523 A CN 115275523A CN 202210774292 A CN202210774292 A CN 202210774292A CN 115275523 A CN115275523 A CN 115275523A
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base film
parts
mof
hydrogel
lithium battery
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张健明
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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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • General Physics & Mathematics (AREA)
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Abstract

The application relates to the field of lithium battery diaphragms, and particularly discloses a diaphragm for a polyethylene-based lithium battery and a preparation method thereof. The diaphragm for the polyvinyl lithium battery comprises a polyethylene base film and at least one layer of modified coating film, wherein the modified coating film is arranged on one side of the polyethylene base film, the modified coating film is prepared from modified coating liquid, and the modified coating liquid comprises the following substances in parts by weight: 45-80 parts of matrix sol solution, 3-8 parts of adhesive, 0.5-2.0 parts of coupling agent, 15-30 parts of absolute ethyl alcohol and 6-8 parts of alumina nano particles. The preparation method comprises the following steps: s1, base film treatment; s2, preparing an MOF hydrogel coating layer; s3, preparing a modified coating layer; the polyethylene base membrane surface after the aluminium oxide nano-particle coating that this application adopted forms porous covering membrane structure, effectively improves its imbibition volume and infiltration performance to the diaphragm imbibition and the ability of keeping liquid have been improved.

Description

Diaphragm for polyvinyl lithium battery and preparation method thereof
Technical Field
The application relates to the field of lithium battery diaphragms, in particular to a diaphragm for a polyethylene-based lithium battery and a preparation method thereof.
Background
In battery applications, a separator is placed between the positive and negative electrodes. The separator, which is one of important components of a lithium battery, not only prevents a short circuit between a positive electrode and a negative electrode due to physical contact, but also effectively transfers ions. Its main function is to enable ion transport and act as a physical barrier to isolate the positive and negative electrodes. Since ions need to be transported through the electrolyte, the wettability of the liquid electrolyte is an important property for evaluating battery separators. The separator must absorb and retain a large amount of liquid electrolyte to achieve low internal resistance and high ionic conductivity. The effective absorption of the liquid electrolyte can inhibit the leakage of the liquid electrolyte in the battery cycle process. The filling speed depends on the type of material, the porosity and the pore size of the separator.
Although polyolefin microporous membranes are widely used as lithium ion battery separators due to good performance, the polyolefin microporous membranes have defects in practical use because of limited thermal stability and strength, so that the polyolefin microporous membranes have poor wettability in polar electrolytes and are difficult to be sufficiently wetted.
In view of the above-mentioned related technologies, the inventor believes that the existing separator for a polyvinyl lithium battery has poor wettability and poor strength and thermal stability during the actual use process, and thus the electrochemical performance of the lithium battery is greatly affected.
Disclosure of Invention
In order to overcome the defect that the electrochemical performance of a lithium ion battery is reduced in the practical use process of the existing diaphragm for the polyvinyl lithium battery, the application provides the diaphragm for the polyvinyl lithium battery and the preparation method thereof.
In a first aspect, the present application provides a method for preparing a separator for a polyvinyl lithium battery, which adopts the following technical scheme:
the preparation method of the diaphragm for the polyvinyl lithium battery comprises a polyethylene base film and at least one layer of modified coating film, wherein the modified coating film is arranged on one side of the polyethylene base film and is prepared from modified coating liquid, and the modified coating liquid comprises the following substances in parts by weight:
45-80 parts of matrix sol liquid;
3-8 parts of an adhesive;
0.5-2.0 parts of a coupling agent;
15-30 parts of absolute ethyl alcohol;
6-8 parts of alumina nano particles.
By adopting the technical scheme, the alumina nano particles are used as the main modified material, the auxiliary matrix sol is used as the load matrix, on one hand, the hardness of the nano alumina particles in the modified coating liquid is better, and the surface of the nano alumina particles is effectively modified by the coupling agent, so that the dispersity of the nano alumina particles is further improved, the distribution uniformity of the nano alumina particles is improved, the toughness and the plasticity of the polyethylene-based film material are effectively improved, and the impact resistance of the polyethylene-based film material is improved.
Meanwhile, a porous coating film structure is formed on the surface of the polyethylene base film coated with the aluminum oxide nanoparticles, and the micropores can ensure the efficient movement of lithium ions between the positive electrode and the negative electrode. The porous coating film formed by the modified coating film effectively improves the liquid absorption volume and the infiltration performance, thereby improving the liquid absorption and retention capacity of the diaphragm.
Preferably, the matrix sol solution is a polypyrrole hydrogel matrix fluid, and the polypyrrole hydrogel matrix fluid is prepared by adopting the following scheme:
mixing tannic acid with water, and collecting base liquid;
dripping the pyrrole monomer solution into the matrix solution in an ice-water bath, stirring and mixing, and collecting a mixed solution;
and adding the ferric chloride solution into the mixed solution, stirring, mixing and standing to obtain the polypyrrole hydrogel matrix fluid.
By adopting the technical scheme, the composition of the matrix sol solution is further optimized, and the added polypyrrole hydrogel material is used as a loaded sol matrix, so that the bonding strength between the alumina nano powder and the polyethylene base film is improved. On the basis, the appearance of a cross-linked structure is regulated and controlled under the interaction of the complexation of metal ions, the non-covalent bond force between tannic acid and polypyrrole and the like, so that a composite material containing a large number of mesoporous structures is formed, a rapid and stable transfer channel is provided for electron transfer and ion transmission, and the multiplying power performance of the diaphragm for the polyvinyl lithium battery is improved.
Preferably, the adhesive comprises one or more of BYK306 auxiliary agent, BYK077 auxiliary agent or BYK346 auxiliary agent.
By adopting the technical scheme, the BYK series auxiliary agent which is preferably selected in the application is used as a modified adhesive material, so that the bonding strength between the alumina nano-particles and the polyethylene base film can be effectively improved.
Preferably, the modified coating film is provided with two layers, and the polyethylene base film is arranged between the two layers of the modified coating film.
By adopting the technical scheme, the structure of the diaphragm for the polyvinyl lithium battery is further optimized, and the electrochemical performance and the mechanical strength of the diaphragm for the polyvinyl lithium battery in the actual use process are effectively improved through the structure that the polyethylene base film is coated by the twice modified coating film.
Preferably, the modified coating film further comprises at least one MOF hydrogel coating layer, and the MOF hydrogel coating layer is arranged between the modified coating film and the polyethylene base film.
By adopting the technical scheme, the hydrogel coating film material with the metal-organic framework compound structure is arranged between the modified coating film and the polyethylene base film, and the metal-organic framework compound is formed by self-assembling metal ions and polydentate organic ligands containing carboxylic acid or nitrogen and the like through coordination bonds, so that the novel composite porous coordination polymer with a highly periodic network structure is provided. The metal organic framework compound hydrogel and the modified coating film form a synergistic effect by being arranged between the modified coating film and the polyethylene base film, and the effects of isolating electrons and transmitting ions are achieved.
The modified coating film and the MOF hydrogel coating layer double-coated diaphragm structure effectively improves the uniformity and uniformity of the surface aperture, effectively improves the wettability and mechanical property, and can prevent the electrode material from falling off to a certain degree. Thereby further improving the defect that the electrochemical performance of the lithium ion battery is reduced in the practical use process of the diaphragm for the polyethylene lithium battery.
Preferably, the MOF hydrogel coating layer is prepared by coating MOF hydrogel, and the MOF hydrogel comprises the following substances in parts by weight:
3-8 parts of MOF particles;
10-15 parts of chitosan;
80-100 parts of deionized water;
6-15 parts of acrylamide;
3-8 parts of polyethylene glycol diacrylate;
1-3 parts of polyethylene glycol diglycidyl ether;
0.1 to 1.2 portions of ammonium persulfate solution.
Preferably, the MOF particles comprise any one of Ni-MOF particles or Fe-MOF particles.
By adopting the technical scheme, the MOF material is prepared from Ni and Fe, and the MOF material of the metal elements of Ni and Fe prepared by the method has good specific surface area of a sensor modified electrode material and good electron transmission capability, so that the diaphragm for the polyvinyl lithium battery prepared by the method has good electrochemical performance.
In a second aspect, the present application provides a method for preparing a separator for a lithium polyvinyl battery, comprising the steps of:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film with acetone, naturally drying, and collecting to obtain a washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating MOF hydrogel on two sides of a washing base film, and drying in an oven after coating to prepare the base film coated with the MOF hydrogel coating layer;
s3, preparing a modified coating layer: and then, soaking the base film coated with the MOF hydrogel coating layer in the modified coating solution, performing dip-coating treatment, and drying in a drying oven to obtain the diaphragm for the polyvinyl lithium battery.
By adopting the technical scheme, the preparation steps are optimized, the uniformity and the uniformity of the surface aperture are effectively improved, the wettability and the mechanical property are improved, and the electrode material can be prevented from falling off to a certain degree through a simple multilayer coating scheme. Meanwhile, the method is simple and easy to implement, saves the cost and improves the preparation efficiency.
In summary, the present application has the following beneficial effects:
firstly, the alumina nano-particles are used as a main modified material, and the auxiliary matrix sol is used as a load matrix, so that on one hand, the hardness of the nano-alumina particles in the modified coating liquid is better, and the surface of the nano-alumina particles is effectively modified through the coupling agent, so that the dispersity of the nano-alumina particles is further improved, the distribution uniformity of the nano-alumina particles is improved, the toughness and plasticity of the polyethylene base film material are effectively improved, and the impact resistance of the polyethylene base film material is improved.
Meanwhile, a porous coating film structure is formed on the surface of the polyethylene base film coated with the aluminum oxide nanoparticles, and the micropores can ensure the efficient movement of lithium ions between the positive electrode and the negative electrode. The porous coating film formed by the modified coating film effectively improves the liquid absorption volume and the infiltration performance, thereby improving the liquid absorption and retention capacity of the diaphragm.
Secondly, the structure of the diaphragm for the polyethylene-based lithium battery is further optimized, and the electrochemical performance and the mechanical strength of the diaphragm for the polyethylene-based lithium battery in the actual use process are effectively improved through the structure that the polyethylene-based base film is coated by the twice modified coating film.
And thirdly, the hydrogel coating film material with the metal-organic framework compound structure is arranged between the modified coating film and the polyethylene base film, and the metal-organic framework compound is formed by self-assembling metal ions and multi-tooth organic ligands containing carboxylic acid or nitrogen and the like through coordination bonds, so that the novel composite porous coordination polymer with a highly periodic network structure is provided. The application further arranges between the modified coating film and the polyethylene base film, so that the metal organic framework compound hydrogel and the modified coating film form a synergistic effect, and the effects of isolating electrons and transmitting ions are achieved.
The modified coating film and the MOF hydrogel coating layer double-coated diaphragm structure effectively improves the uniformity and uniformity of the surface aperture, effectively improves the wettability and mechanical property, and can prevent the electrode material from falling off to a certain degree. Thereby further improving the defect that the electrochemical performance of the lithium ion battery is reduced in the practical use process of the diaphragm for the polyvinyl lithium battery.
Detailed Description
The present application will be described in further detail with reference to examples.
Preparation example
Preparation example 1
Preparation of polypyrrole hydrogel matrix fluid: mixing 0.5g tannic acid with 0.15L water, and collecting base liquid;
5g of pyrrole monomer solution is dripped into the matrix solution in an ice-water bath at the temperature of 0 ℃, stirred and mixed at the speed of 1000r/min, and mixed solution is collected;
adding 60g of 3mol/L ferric chloride solution into the mixed solution, stirring and mixing, and standing in an ice water bath to obtain the polypyrrole hydrogel matrix fluid.
Preparation example 2
Preparation of modified coating solution 1: 4.5kg of polypyrrole hydrogel matrix liquid, 0.3kg of BYK306 auxiliary agent, 0.05kg of silane coupling agent KH-550, 1.5kg of absolute ethyl alcohol and 0.6kg of alumina nano-particles are taken, stirred and mixed to prepare the modified coating liquid 1.
Preparation example 3
Preparation of modified coating liquid 2: taking 6kg of polypyrrole hydrogel matrix fluid, 0.5kg of BYK306 auxiliary agent, 0.1kg of silane coupling agent KH-550, 2.2kg of absolute ethyl alcohol and 0.7kg of alumina nano particles, and stirring and mixing to prepare the modified coating solution 2.
Preparation example 4
Preparing a modified coating solution 3: 8kg of polypyrrole hydrogel matrix fluid, 0.8kg of BYK306 auxiliary agent, 0.2kg of silane coupling agent KH-550, 3.0kg of absolute ethyl alcohol and 0.8kg of alumina nano-particles are taken, stirred and mixed to prepare the modified coating liquid 3.
Preparation example 5
The modified coating solution 4 is different from the preparation example 2 in that the BYK077 additive used in the preparation example is used in place of the BYK306 additive, and the other conditions and the preparation method are the same as those in the preparation example 2.
Preparation example 6
The modified coating solution 5 is different from preparation example 2 in that the BYK346 aid used in this preparation example is used instead of the BYK306 aid, and the other conditions and preparation method are the same as those in preparation example 2.
Preparation example 7
MOF particle 1:
adding 0.5g of nickel chloride, 0.04g of trimesic acid and 0.5kg of water into 2kg of DMF, stirring, mixing, reacting at 90 ℃ for 10 hours under heat preservation, collecting reaction liquid, washing the reaction liquid with DMF and deionized water respectively, and drying in vacuum to obtain the MOF particle 1.
Preparation example 8
MOF particle 2:
adding 0.48g of ferric chloride, 0.04g of trimesic acid and 0.5kg of water into 2kg of DMF, stirring, mixing, reacting at 90 ℃ for 10 hours under heat preservation, collecting reaction liquid, washing the reaction liquid with DMF and deionized water respectively, and drying in vacuum to obtain the MOF particle 2.
Preparation example 9
MOF hydrogel 1:
taking 3kg of MOF particles 1, 10kg of chitosan, 80kg of deionized water, 6kg of acrylamide, 3kg of polyethylene glycol diacrylate, 1kg of polyethylene glycol diglycidyl ether and 0.1kg of ammonium persulfate solution with the mass fraction of 0.4%, stirring and mixing to prepare the MOF hydrogel 1.
Preparation example 10
MOF hydrogel 2:
taking 5kg of MOF particles 1, 12kg of chitosan, 90kg of deionized water, 11kg of acrylamide, 5kg of polyethylene glycol diacrylate, 2kg of polyethylene glycol diglycidyl ether and 0.6kg of ammonium persulfate solution with the mass fraction of 0.4%, stirring and mixing to prepare the MOF hydrogel 2.
Preparation example 11
8kg of MOF particles 1, 15kg of chitosan, 100kg of deionized water, 15kg of acrylamide, 8kg of polyethylene glycol diacrylate, 3kg of polyethylene glycol diglycidyl ether and 1.2kg of ammonium persulfate solution with the mass fraction of 0.4 percent are stirred and mixed to prepare the MOF hydrogel 3.
Preparation example 12
MOF hydrogel 4:
stirring and mixing 5kg of MOF particles 2, 12kg of chitosan, 90kg of deionized water, 11kg of acrylamide, 5kg of polyethylene glycol diacrylate, 2kg of polyethylene glycol diglycidyl ether and 0.6kg of ammonium persulfate solution with the mass fraction of 0.4 percent to prepare the MOF hydrogel 4.
Examples
Example 1
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and (3) dipping one side of the washed base film in the modified coating solution 1, performing dip-coating treatment, and drying in an oven to obtain the diaphragm for the modified coating film polyvinyl lithium battery with the thickness of 0.3 mu m.
Example 2
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and dipping one side of the washed base film into the modified coating liquid 2, performing dip-coating treatment, and drying in an oven to obtain the modified coating film polyvinyl lithium battery diaphragm with the thickness of 0.3 mu m.
Example 3
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and (3) soaking one side of the washed base film in the modified coating solution 3, performing dip-coating treatment, and drying in an oven to obtain the diaphragm for the modified coating film polyvinyl lithium battery with the thickness of 0.3 mu m.
Example 4
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and (3) soaking one side of the washed base film in the modified coating solution 4, performing dip-coating treatment, and drying in an oven to obtain the diaphragm for the modified coating film polyvinyl lithium battery with the thickness of 0.3 mu m.
Example 5
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and (3) soaking one side of the washed base film in the modified coating solution 5, performing dip-coating treatment, and drying in an oven to obtain the diaphragm for the modified coating film polyvinyl lithium battery with the thickness of 0.3 mu m.
Example 6
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing a modified coating layer: and (3) completely soaking the washed base film in the modified coating solution 1, performing dip-coating treatment, and drying in an oven to obtain two layers of modified coating film polyvinyl lithium battery diaphragms with the thickness of 0.3 mu m.
Example 7
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating the MOF hydrogel 1 on two sides of a washing base film, and drying in an oven after coating to prepare the base film coated with the MOF hydrogel coating layer with the thickness of 0.3 mu m;
s3, preparing a modified coating layer: and (3) completely soaking the base film with the MOF hydrogel coating layer into the modified coating liquid 1, performing dip-coating treatment, and drying in an oven to obtain two layers of modified coating film polyvinyl lithium battery diaphragms with the thickness of 0.3 mu m.
Example 8
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating the MOF hydrogel 2 on two sides of a washing base film, and drying in an oven after coating to prepare the base film coated with the MOF hydrogel coating layer with the thickness of 0.3 mu m;
s3, preparing a modified coating layer: and (3) completely soaking the base film with the MOF hydrogel coating layer into the modified coating liquid 1, performing dip-coating treatment, and drying in an oven to obtain two layers of modified coating film polyvinyl lithium battery diaphragms with the thickness of 0.3 mu m.
Example 9
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating the MOF hydrogel 3 on two sides of a washing base film, and drying in a drying oven after the coating is finished to prepare the base film coated with the MOF hydrogel coating layer with the thickness of 0.3 mu m;
s3, preparing a modified coating layer: and (3) completely soaking the base film with the MOF hydrogel coating layer into the modified coating liquid 1, performing dip-coating treatment, and drying in an oven to obtain two layers of modified coating film polyvinyl lithium battery diaphragms with the thickness of 0.3 mu m.
Example 10
A preparation method of a diaphragm for a polyvinyl lithium battery comprises the following steps:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film by using acetone, naturally drying the polyethylene base film at room temperature, and collecting the washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating the MOF hydrogel 4 on two sides of a washing base film, and drying in an oven after coating to prepare the base film coated with the MOF hydrogel coating layer with the thickness of 0.3 mu m;
s3, preparing a modified coating layer: and (3) completely soaking the base film with the MOF hydrogel coating layer into the modified coating solution 1, performing dip-coating treatment, and drying in a drying oven to obtain two layers of 0.3-micron-thick modified coating film polyvinyl lithium battery diaphragms.
Comparative example
Comparative example 1
A separator for a lithium battery, which is different from example 1 in that the separator for a lithium battery was assembled using a polyethylene film as it is in comparative example 1.
Comparative example 2
A separator for a lithium battery, which is different from example 1 in that silica nanoparticles are used instead of alumina nanoparticles in the modified coating liquid used in comparative example 1.
Performance test
The separators for lithium batteries prepared in examples 1 to 10 and comparative examples 1 to 2 were tested for wettability, mechanical strength and ionic conductivity.
Wettability: and (4) testing the contact angle. The diaphragm sample is flatly placed on a test bearing table of a contact angle measuring instrument, deionized water is used as a reagent, the test amount is 35 mu L, and contact angle data are recorded after liquid drops are dripped for 30 s.
Adopt the puncture intensity of intelligent stretcher test diaphragm sample, the sample preparation of puncture intensity: cutting the diaphragm sample into a square with the side length of 10 cm;
ionic conductivity: cutting the sample diaphragm into a wafer with the diameter of 19mm by a stamping method, recording the thickness D of the test sample wafer, placing the sample diaphragm soaked with the electrolyte between two identical gaskets, and assembling the sample diaphragm into the button cell in a glove box under the atmosphere of argon.
And (3) testing conditions: using an electrochemical workstation, setting the AC amplitude to 10mV and the scanning frequency to 1-1 × 106Hz. Obtaining the resistance Rb of the diaphragm at the moment from an alternating current impedance spectrogram obtained by an electrochemical workstation, and obtaining the ionic conductivity of the sample diaphragm through calculation: δ = D/(Rb × S).
The results of the above test tests are shown in table 1.
TABLE 1 Performance test Table
Sample(s) Contact angle/° Puncture Strength/N Ion conductivity/mS/cm
Example 1 7.2 6.58 1.05
Example 2 7.1 6.62 1.08
Example 3 7.3 6.60 1.06
Example 4 7.0 6.65 1.05
Example 5 7.2 6.62 1.06
Example 6 7.2 6.85 1.15
Example 7 7.2 7.23 1.45
Example 8 7.4 7.25 1.48
Example 9 7.2 7.28 1.46
Example 10 7.4 7.16 1.43
Comparative example 1 116 5.64 0.55
Comparative example 2 25 5.84 0.62
By combining the performance test tables of examples 1 to 10, comparative examples 1 to 1 and table 1, comparison can be found out that:
the examples 1 to 5, 6, 7 to 10 and the comparative examples 1 to 2 were compared as a comparative group, specifically as follows:
(1) Firstly, comparing the performances of the embodiments 1-5 with the comparative examples 1-2, and as can be seen from the data in table 1, the data of the embodiments 1-5 are obviously superior to the data of the comparative examples 1-2, which indicates that the technical scheme of the application adopts the alumina nanoparticles as the main modified material and the auxiliary matrix sol as the load matrix, on one hand, the hardness of the nano alumina particles in the modified coating liquid is better, and the surface of the nano alumina particles is effectively modified by the coupling agent, so that the dispersibility of the nano alumina particles is further improved, the uniform distribution performance of the nano alumina particles is improved, the toughness and plasticity of the polyethylene base film material are effectively improved, and the impact resistance of the polyethylene base film material is improved.
Meanwhile, a porous coating film structure is formed on the surface of the polyethylene base film coated with the aluminum oxide nanoparticles, and the micropores can ensure the efficient movement of lithium ions between the positive electrode and the negative electrode. The porous coating film formed by the modified coating film effectively improves the liquid absorption volume and the infiltration performance, thereby improving the liquid absorption and retention capacity of the diaphragm.
(2) Comparing the embodiment 6 with the embodiment 1, the data of the embodiment 6 further reflects that the structure of the diaphragm for the polyvinyl lithium battery is further optimized, and the electrochemical performance and the mechanical strength of the diaphragm for the polyvinyl lithium battery in the actual use process are effectively improved through the structure that the polyethylene base film is coated by the twice modified coating film.
(3) Comparing examples 7 to 10 with example 6, it can be found by combining the data in table 1 that a hydrogel coating material having a metal-organic framework compound structure is disposed between the modified coating film and the polyethylene base film, and the metal-organic framework compound is a novel composite porous coordination polymer having a highly periodic network structure, which is formed by self-assembling metal ions and multidentate organic ligands containing carboxylic acid or nitrogen through coordination bonds. The application further arranges between the modified coating film and the polyethylene base film, so that the metal organic framework compound hydrogel and the modified coating film form a synergistic effect, and the effects of isolating electrons and transmitting ions are achieved.
The modified coating film and the MOF hydrogel coating layer double-coated diaphragm structure effectively improves the uniformity and uniformity of the surface aperture, effectively improves the wettability and mechanical property, and can prevent the electrode material from falling off to a certain degree. Thereby further improving the defect that the electrochemical performance of the lithium ion battery is reduced in the practical use process of the diaphragm for the polyvinyl lithium battery.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims (8)

1. The diaphragm for the polyethylene-based lithium battery is characterized by comprising a polyethylene base film and at least one layer of modified coating film, wherein the modified coating film is arranged on one side of the polyethylene base film and is prepared from modified coating liquid, and the modified coating liquid comprises the following substances in parts by weight:
45-80 parts of matrix sol liquid;
3-8 parts of an adhesive;
0.5-2.0 parts of a coupling agent;
15-30 parts of absolute ethyl alcohol;
6-8 parts of aluminum oxide nanoparticles.
2. The separator for a polyvinyl lithium battery as claimed in claim 1, wherein the matrix sol solution is a polypyrrole hydrogel matrix fluid, and the polypyrrole hydrogel matrix fluid is prepared by the following scheme:
mixing tannic acid with water, and collecting the base fluid;
in an ice water bath, dripping the pyrrole monomer solution into the matrix solution, stirring and mixing, and collecting a mixed solution;
and adding the ferric chloride solution into the mixed solution, stirring, mixing and standing to obtain the polypyrrole hydrogel matrix fluid.
3. The separator as claimed in claim 1, wherein the adhesive comprises any one or more of BYK306 aid, BYK077 aid, or BYK346 aid.
4. The separator for a polyvinyl lithium battery as claimed in claim 1, wherein the modified coating film is provided with two layers, and the polyethylene-based film is provided between the two layers of the modified coating film.
5. The separator for the polyvinyl lithium battery as claimed in claim 1, wherein the modified coating film further comprises at least one MOF hydrogel coating layer, and the MOF hydrogel coating layer is disposed between the modified coating film and the polyethylene base film.
6. The separator for the polyvinyl lithium battery as claimed in claim 5, wherein the MOF hydrogel coating layer is prepared by coating MOF hydrogel, and the MOF hydrogel comprises the following materials in parts by weight:
3-8 parts of MOF particles;
10-15 parts of chitosan;
80-100 parts of deionized water;
6-15 parts of acrylamide;
3-8 parts of polyethylene glycol diacrylate;
1-3 parts of polyethylene glycol diglycidyl ether;
0.1-1.2 parts of ammonium persulfate solution.
7. The separator of claim 6, wherein the MOF particles comprise any one of Ni-MOF particles or Fe-MOF particles.
8. The method for preparing a separator for a lithium polyvinyl battery according to any one of claims 1 to 7, comprising the steps of:
s1, base film treatment: taking a polyethylene base film, washing the polyethylene base film with acetone, naturally drying, and collecting to obtain a washed base film;
s2, preparing an MOF hydrogel coating layer: respectively coating MOF hydrogel on two sides of a washing base film, and drying in a drying oven after coating to prepare the base film coated with the MOF hydrogel coating layer;
s3, preparing a modified coating layer: and then, dipping the base film coated with the MOF hydrogel coating layer into the modified coating liquid, carrying out dip-coating treatment, and drying in an oven to obtain the diaphragm for the polyvinyl lithium battery.
CN202210774292.9A 2022-07-01 2022-07-01 Diaphragm for polyvinyl lithium battery and preparation method thereof Pending CN115275523A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105047845A (en) * 2015-06-19 2015-11-11 深圳市星源材质科技股份有限公司 High-dielectric constant nano-composite coating diaphragm and preparation method thereof
CN108630867A (en) * 2018-05-02 2018-10-09 桑德集团有限公司 Diaphragm and preparation method thereof, lithium ion battery
CN110048062A (en) * 2019-03-25 2019-07-23 惠州锂威电子科技有限公司 A kind of anti-overcharge battery diaphragm and the lithium ion battery using the diaphragm
CN113394405A (en) * 2021-05-24 2021-09-14 西安交通大学 Preparation method of electrode coating for actively preventing thermal runaway of lithium ion battery
CN114191996A (en) * 2020-08-26 2022-03-18 中南大学 Preparation method of super-hydrophobic super-oleophylic lithium-air battery composite diaphragm

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105047845A (en) * 2015-06-19 2015-11-11 深圳市星源材质科技股份有限公司 High-dielectric constant nano-composite coating diaphragm and preparation method thereof
CN108630867A (en) * 2018-05-02 2018-10-09 桑德集团有限公司 Diaphragm and preparation method thereof, lithium ion battery
CN110048062A (en) * 2019-03-25 2019-07-23 惠州锂威电子科技有限公司 A kind of anti-overcharge battery diaphragm and the lithium ion battery using the diaphragm
CN114191996A (en) * 2020-08-26 2022-03-18 中南大学 Preparation method of super-hydrophobic super-oleophylic lithium-air battery composite diaphragm
CN113394405A (en) * 2021-05-24 2021-09-14 西安交通大学 Preparation method of electrode coating for actively preventing thermal runaway of lithium ion battery

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