CN110600662A - Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof - Google Patents
Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof Download PDFInfo
- Publication number
- CN110600662A CN110600662A CN201910886256.XA CN201910886256A CN110600662A CN 110600662 A CN110600662 A CN 110600662A CN 201910886256 A CN201910886256 A CN 201910886256A CN 110600662 A CN110600662 A CN 110600662A
- Authority
- CN
- China
- Prior art keywords
- titanium dioxide
- hexafluoropropylene
- polyvinylidene fluoride
- composite membrane
- dioxide composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- 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
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- 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
- H01M50/44—Fibrous 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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Nanotechnology (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Materials Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Cell Separators (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention provides a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and a preparation method and application thereof, belonging to the technical field of lithium battery diaphragms. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane provided by the invention comprises polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano fiber and dibutyl phthalate. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane provided by the invention still does not have the phenomenon of thermal shrinkage at the temperature of 150 ℃, can be normally used at the temperature of 110 ℃, has high porosity, has the porosity of 50-70%, has good affinity with electrolyte, and can be used as a lithium battery diaphragm.
Description
Technical Field
The invention relates to the technical field of lithium battery diaphragms, in particular to a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and a preparation method and application thereof.
Background
Lithium ion batteries have been widely used in portable electronic devices, electric vehicles, tools, and the like because of their advantages of high energy density, low self-discharge, long cycle life, and environmental friendliness. In the construction of lithium batteries, the separator is one of the key internal layer components. The diaphragm is used for isolating the positive and negative electrode materials and transmitting lithium ions, and the safety performance and the service life of the lithium ion battery are directly influenced by the performance of the diaphragm.
With the development of the field of lithium ion batteries, the market has higher and higher requirements on the performance of the lithium ion batteries, and simultaneously, the requirements on the diaphragm are also increased sharply. An ideal separator should have good ionic conductivity, chemical stability, and good wettability and storability to the electrolyte. The existing commercial lithium battery diaphragm mainly adopts a polyethylene and polypropylene microporous membrane, but the diaphragm has the defects of poor heat resistance, low porosity and poor electrolyte affinity.
Disclosure of Invention
The invention aims to provide a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane, a preparation method and application thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane, which comprises the components of polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano fiber and dibutyl phthalate.
Preferably, the mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the carboxyl modified titanium dioxide nano-fiber to the dibutyl phthalate is 1: 0.05-0.15: 0.05-0.1.
Preferably, the preparation method of the carboxyl modified titanium dioxide nanofiber comprises the following steps:
mixing and grinding titanium dioxide nano-fibers and citric acid, dispersing in water, and centrifuging to obtain the carboxyl modified titanium dioxide nano-fibers.
Preferably, the mass ratio of the titanium dioxide nanofiber to the citric acid is 1: 0.5-1.5.
Preferably, the diameter of the titanium dioxide nanofiber is 50-300 nm, and the length of the titanium dioxide nanofiber is 1-100 microns.
Preferably, the porosity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane is 50-70%, and the pore diameter is 0.5-10 μm.
The invention also provides a preparation method of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane in the technical scheme, which comprises the following steps:
mixing polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano-fiber, dibutyl phthalate and a solvent to obtain mixed slurry;
coating the mixed slurry to obtain a composite membrane wet membrane;
and soaking the composite membrane wet membrane in a coagulating bath for phase transfer, and then drying to obtain the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane.
Preferably, the solvent is N-methylpyrrolidone.
Preferably, the temperature of the phase transfer is 20-40 ℃, and the time is 12-24 h.
The invention also provides an application of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane in the technical scheme or the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained by the preparation method in the technical scheme as a lithium battery diaphragm.
The invention provides a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane, which comprises the components of polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano fiber and dibutyl phthalate. According to the preparation method, polyvinylidene fluoride-hexafluoropropylene is used as a substrate, carboxyl modified titanium dioxide nano fiber is used as a doping material, dibutyl phthalate is used as a plasticizer, and in the process of preparing the composite membrane, the carboxyl modified titanium dioxide nano fiber can reduce the crystallinity of polyvinylidene fluoride-hexafluoropropylene, so that the porosity of the composite membrane is improved, the affinity of the composite membrane and an electrolyte is enhanced, and meanwhile, the high temperature resistance of the composite membrane is effectively improved by doping the carboxyl modified titanium dioxide nano fiber. Experimental results show that the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane provided by the invention still does not have the phenomenon of thermal shrinkage at the temperature of 150 ℃, can be normally used at the temperature of 110 ℃, has high porosity, has the porosity of 50-70%, has good affinity with electrolyte, and can be used as a lithium battery diaphragm.
The invention also provides a preparation method of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane in the technical scheme, which comprises the following steps: mixing polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano-fiber, dibutyl phthalate and a solvent to obtain mixed slurry; coating the mixed slurry to obtain a composite membrane wet membrane; and soaking the composite membrane wet membrane in a coagulating bath for phase transfer, and then drying to obtain the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane. The method has the advantages of simple process, short period, energy conservation and environmental protection.
Drawings
FIG. 1 is an SEM image of the PVDF-HFP/TiO composite film obtained in examples 1-2;
FIG. 2 is a macro-scale diagram of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films obtained in examples 1-3, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1 and a commercial PP film after heat treatment;
FIG. 3 is a graph showing the shrinkage rates of the PVDF-HFP/Titania composite film obtained in example 2 and a commercial PP film after heat treatment at different temperatures;
FIG. 4 is a graph showing the results of a contact angle test of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 1 and a commercial PP film with an electrolyte, respectively;
FIG. 5 is a graph showing the battery cycle performance at 110 ℃ of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 2, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1, and a commercial PP film;
FIG. 6 is an impedance spectrum of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films obtained in examples 1-3, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1 and a commercial PP film at room temperature;
FIG. 7 is a graph showing the results of ionic conductivity at room temperature of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films obtained in examples 1 to 3, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1, and the commercial PP film.
Detailed Description
The invention provides a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane, which comprises the components of polyvinylidene fluoride-hexafluoropropylene (which can be abbreviated as PVDF-HFP), carboxyl modified titanium dioxide nano fiber and dibutyl phthalate (which can be abbreviated as DBP).
In the invention, the mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the carboxyl modified titanium dioxide nanofiber is preferably 1: 0.05-0.15, and more preferably 1: 0.08-0.12. According to the invention, the polyvinylidene fluoride-hexafluoropropylene is used as a substrate of the composite membrane, the carboxyl modified titanium dioxide nano fiber is used as a doping material to be dispersed in the substrate, the porosity of the composite membrane is effectively improved by adding the doping material, the affinity of the composite membrane and an electrolyte is further improved, and meanwhile, the titanium dioxide nano fiber has excellent heat resistance and can effectively improve the high temperature resistance of the composite membrane; in addition, the titanium dioxide nano-fibers are distributed in the substrate in a disordered way, and the growth of lithium dendrites can be inhibited to a certain extent, so that the mechanical strength of the composite membrane is improved.
In the present invention, the preparation method of the carboxyl-modified titanium dioxide nanofiber preferably comprises the following steps:
mixing and grinding titanium dioxide nano-fibers and citric acid, dispersing in water, and centrifuging to obtain the carboxyl modified titanium dioxide nano-fibers.
According to the invention, titanium dioxide nano-fibers and citric acid are mixed and ground to obtain a mixture of titanium dioxide nano-fibers and citric acid. In the invention, the mixing and grinding can make the mixing of the titanium dioxide nano-fiber and the citric acid more uniform.
In the invention, the diameter of the titanium dioxide nanofiber is preferably 50-300 nm, and more preferably 100-300 nm; the length is preferably 1 to 100 μm. In the invention, the titanium dioxide nano-fiber with the specification is beneficial to being uniformly dispersed in polyvinylidene fluoride-hexafluoropropylene.
In the invention, the mass ratio of the titanium dioxide nanofibers to the citric acid is preferably 1: 0.5-1.5, and more preferably 1: 0.8-1.2.
In the present invention, the source of the titanium dioxide nanofiber is not particularly limited, and may be a commercially available product or may be prepared by a method known to those skilled in the art, and in the embodiment of the present invention, after a titanium dioxide nanofiber precursor is prepared by an electrospinning method, it is preferably calcined at 550 ℃ to obtain the titanium dioxide nanofiber.
After the mixture of the titanium dioxide nano fiber and the citric acid is obtained, the mixture of the titanium dioxide nano fiber and the citric acid is dispersed in water, and then the mixture is centrifuged and dried in sequence to obtain the carboxyl modified titanium dioxide nano fiber.
In the invention, the time for dispersing the titanium dioxide nanofiber and citric acid mixture in water is preferably 1-2 h; the dispersion is preferably carried out by stirring. In the invention, the mixture of the titanium dioxide nano-fiber and the citric acid is dispersed in water, the citric acid which is free in the water is coated on the surface of the titanium dioxide fiber to form the titanium dioxide nano-fiber with carboxyl, and carboxyl groups on the titanium dioxide nano-fiber with carboxyl are mutually exclusive, so that the titanium dioxide nano-fiber modified by carboxyl is uniformly dispersed.
In the invention, the rotation speed of the centrifugation is preferably 8000-12000 rpm, more preferably 10000rpm, and the time of the centrifugation is preferably 3-7 min, more preferably 5 min.
In the present invention, the mass ratio of polyvinylidene fluoride-hexafluoropropylene to dibutyl phthalate (abbreviated as DBP) is preferably 1:0.05 to 0.1, and more preferably 1:0.07 to 0.08. In the invention, the DBP is used as a plasticizer and dispersed in the substrate, so that the mechanical property of the composite film can be improved.
In the invention, the porosity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane is preferably 50-70%, and more preferably 55-65%; the pore diameter is preferably 0.5-10 μm, and more preferably 3-8 μm; the thickness is preferably 25 to 35 μm, and more preferably 28 to 32 μm; the holes in the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane are communicated with each other.
The invention also provides a preparation method of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane in the technical scheme, which comprises the following steps:
mixing polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano-fiber, dibutyl phthalate and a solvent to obtain mixed slurry;
coating the mixed slurry to obtain a composite membrane wet membrane;
and soaking the composite membrane wet membrane in a coagulating bath for phase transfer, and then drying to obtain the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane.
The preparation method comprises the steps of mixing polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano fibers, dibutyl phthalate and a solvent to obtain mixed slurry.
In the present invention, the solvent is preferably N-methylpyrrolidone; the N-methyl pyrrolidone is mutually soluble with water and is easy to remove.
In the invention, the preferable mixing is that polyvinylidene fluoride-hexafluoropropylene and carboxyl modified titanium dioxide nano-fiber are respectively mixed with solvent, then the dispersion liquid of the polyvinylidene fluoride-hexafluoropropylene and the carboxyl modified titanium dioxide nano-fiber is mixed, and dibutyl phthalate is added; the concentration of the carboxyl modified titanium dioxide nano fiber after being dispersed in the solvent is preferably 0.02-0.1 g/mL; the concentration of the solution obtained by dissolving the polyvinylidene fluoride-hexafluoropropylene in the solvent is preferably 0.1 g/mL; in the embodiment of the present invention, the polyvinylidene fluoride-hexafluoropropylene and the carboxyl-modified titanium dioxide nanofibers are respectively dispersed in the solvent preferably by stirring, and the stirring time is preferably 12 hours; after adding the dibutyl phthalate, stirring is preferably continued for 2 hours to obtain a mixed slurry.
After the mixed slurry is obtained, the mixed slurry is preferably defoamed in the present invention. The defoaming mode is not particularly limited, and the conventional defoaming mode can be adopted, such as standing and vacuum defoaming. In the invention, defoaming can remove gas in the mixed slurry to facilitate uniform coating on a glass plate.
After defoaming is finished, the mixed slurry after defoaming is coated to obtain a composite membrane wet membrane.
The specific mode of the coating film is not particularly limited, and the required composite film can be obtained. In the embodiment of the present invention, the coating film is preferably a wet composite film formed by coating the defoamed mixed slurry on a glass plate.
After the composite membrane wet film is obtained, the composite membrane wet film is soaked in a coagulating bath for phase transfer, and then is dried, so that the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane is obtained.
In the present invention, the coagulation bath is preferably water; the temperature of the phase transfer is preferably 20-40 ℃, and the time is preferably 12-24 h. In the invention, in the phase transfer process, the N-methyl pyrrolidone and water carry out mass transfer exchange, the water is filled in the wet film of the composite film, and then the three-dimensional pore structure is obtained after drying and water evaporation.
In the invention, the drying is preferably air-blast drying, the drying temperature is preferably 55-65 ℃, and the drying time is preferably 10-14 h.
The invention also provides an application of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane in the technical scheme or the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained by the preparation method in the technical scheme as a lithium battery diaphragm.
The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane provided by the present invention, the preparation method and the application thereof are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.
Example 1
(1) Mixing ethanol, acetic acid and tetrabutyl titanate according to the mass ratio of 10:4:3, magnetically stirring for 2 hours at normal temperature, adding polyvinylpyrrolidone with the concentration of 0.045g/mL, stirring until the polyvinylpyrrolidone is completely dissolved to obtain a titanium dioxide precursor solution, then obtaining a titanium dioxide nanofiber precursor by an electrostatic spinning method, calcining the titanium dioxide nanofiber precursor for 2 hours at 550 ℃ to obtain titanium dioxide nanofibers, wherein the diameter of the titanium dioxide nanofibers is 100-300 nm, and the length of the titanium dioxide nanofibers is 1-100 micrometers;
(2) mixing and grinding titanium dioxide nano-fibers and citric acid according to the mass ratio of 1:1, dispersing in water, stirring for 2h, and centrifuging at 10000rpm for 5min to obtain carboxyl modified titanium dioxide nano-fibers;
(3) adding the carboxyl modified titanium dioxide nano-fiber into an N-methyl pyrrolidone solvent, and stirring for 12h to obtain a carboxyl modified titanium dioxide nano-fiber dispersion liquid with the concentration of 0.025 g/mL;
(4) adding polyvinylidene fluoride-hexafluoropropylene into N-methyl pyrrolidone, and stirring for 12 hours to obtain a polyvinylidene fluoride-hexafluoropropylene solution with the concentration of 0.1 g/mL;
(5) sequentially adding the carboxyl modified titanium dioxide nanofiber dispersion liquid obtained in the step (3) and dibutyl phthalate into the polyvinylidene fluoride-hexafluoropropylene solution obtained in the step (4), stirring for 2 hours, and then standing and defoaming for 12 hours to obtain mixed slurry; wherein the mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the carboxyl modified titanium dioxide nano fiber to the dibutyl phthalate is 1:0.05:0.25
(6) Coating the mixed slurry on a glass plate, immersing the glass plate in water at 30 ℃, drying the glass plate for 12 hours at 60 ℃ after immersing the glass plate in the water for 12 hours to obtain a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film with the thickness of 20-25 mu m, and marking the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film asPVDF-HFP/DBP/TiO2(5％)。
The porosity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in the embodiment is 55% through testing, and the range of the tested pore diameter is 2-5 mu m.
Example 2
(1) Mixing ethanol, acetic acid and tetrabutyl titanate according to the mass ratio of 10:4:3, magnetically stirring for 2 hours at normal temperature, adding polyvinylpyrrolidone with the concentration of 0.045g/mL, stirring until the polyvinylpyrrolidone is completely dissolved to obtain a titanium dioxide precursor solution, then obtaining a titanium dioxide nanofiber precursor by an electrostatic spinning method, calcining the titanium dioxide nanofiber precursor for 2 hours at 550 ℃ to obtain titanium dioxide nanofibers, wherein the diameter of the titanium dioxide nanofibers is 100-300 nm, and the length of the titanium dioxide nanofibers is 1-100 micrometers;
(2) mixing and grinding titanium dioxide nano fibers and citric acid according to the mass ratio of 1:1, dispersing in water, stirring for 2h, and centrifuging at 10000rpm for 5min to obtain carboxyl modified titanium dioxide nano fibers;
(3) adding the carboxyl modified titanium dioxide nano fiber into an N-methyl pyrrolidone solvent, and stirring for 12 hours to obtain a carboxyl modified titanium dioxide nano fiber dispersion liquid with the concentration of 0.05 g/mL;
(4) adding polyvinylidene fluoride-hexafluoropropylene into N-methyl pyrrolidone, and stirring for 12 hours to obtain a polyvinylidene fluoride-hexafluoropropylene solution with the concentration of 0.1 g/mL;
(5) sequentially adding the carboxyl modified titanium dioxide nanofiber dispersion liquid obtained in the step (3) and dibutyl phthalate into the polyvinylidene fluoride-hexafluoropropylene solution obtained in the step (4), stirring for 2 hours, and then standing and defoaming for 12 hours to obtain mixed slurry; wherein the mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the carboxyl modified titanium dioxide nano fiber to the dibutyl phthalate is 1:0.10: 0.25;
(6) coating the mixed slurry on a glass plate, immersing the glass plate in water at 30 ℃, drying the glass plate for 12 hours at 60 ℃ after immersing the glass plate in the water for 12 hours to obtain polyvinylidene fluoride-hexafluoropropylene/di-n-butyl rubber with the thickness of 20-25 mu mTitanium oxide composite membranes, noted as PVDF-HFP/DBP/TiO2(10％)。
The porosity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in the embodiment is 56% through testing, and the range of the tested pore diameter is 2-5 mu m.
Example 3
(1) Mixing ethanol, acetic acid and tetrabutyl titanate according to the mass ratio of 10:4:3, magnetically stirring for 2 hours at normal temperature, adding polyvinylpyrrolidone with the concentration of 0.045g/mL, stirring until the polyvinylpyrrolidone is completely dissolved to obtain a titanium dioxide precursor solution, then obtaining a titanium dioxide nanofiber precursor by an electrostatic spinning method, calcining the titanium dioxide nanofiber precursor for 2 hours at 550 ℃ to obtain titanium dioxide nanofibers, wherein the diameter of the titanium dioxide nanofibers is 100-300 nm, and the length of the titanium dioxide nanofibers is 1-100 micrometers;
(2) mixing and grinding titanium dioxide nano fibers and citric acid according to the mass ratio of 1:1, dispersing in water, stirring for 2h, and centrifuging at 10000rpm for 5min to obtain carboxyl modified titanium dioxide nano fibers;
(3) adding the carboxyl modified titanium dioxide nano fiber into an N-methyl pyrrolidone solvent, and stirring for 12 hours to obtain a carboxyl modified titanium dioxide nano fiber dispersion liquid with the concentration of 0.075 g/mL;
(4) adding polyvinylidene fluoride-hexafluoropropylene into N-methyl pyrrolidone, and stirring for 12 hours to obtain a polyvinylidene fluoride-hexafluoropropylene solution with the concentration of 0.1 g/mL;
(5) sequentially adding the carboxyl modified titanium dioxide nanofiber dispersion liquid obtained in the step (3) and dibutyl phthalate into the polyvinylidene fluoride-hexafluoropropylene solution obtained in the step (4), stirring for 2 hours, and then standing and defoaming for 12 hours to obtain mixed slurry; wherein the mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the carboxyl modified titanium dioxide nano fiber to the dibutyl phthalate is 1:0.15: 0.25;
(6) coating the mixed slurry on a glass plate, immersing the glass plate in water at 30 ℃, drying the glass plate at 60 ℃ for 12 hours after immersing the glass plate in the water for 12 hours to obtain the polymer with the thickness of 20-25 mu mComposite film of vinylidene fluoride, hexafluoropropylene and titanium dioxide, as PVDF-HFP/DBP/TiO2(15％)。
The porosity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in the embodiment is tested to be 60%, and the test pore diameter range is 2-5 μm.
Comparative example 1
According to the method of the embodiment 1, a polyvinylidene fluoride-hexafluoropropylene film (marked as PVDF/DBP) is prepared without adding the titanium dioxide nano fiber modified by carboxyl, and the thickness of the obtained PVDF/DBP is 20-25 μm.
The porosity of the polyvinylidene fluoride-hexafluoropropylene film obtained by the comparative example is 51.7, and the range of the tested aperture is 1-3 mu m.
The morphology of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in example 1-2 is characterized, and the result is shown in fig. 1, wherein (a) and (b) are SEM images of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in example 1 at different magnifications, and (c) and (d) are SEM images of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane obtained in example 2 at different magnifications. The composite films obtained in examples 1 to 2 were found to have a large number of pore structures from (a) and (c), and the pore structures in the composite films obtained in examples 1 to 2 were found to communicate with each other from (b) and (d).
The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films obtained in examples 1 to 3, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1 and a commercial PP film (polypropylene film) are all cut into circles with the same size, and then after heat treatment at 150 ℃ for 0.5h, macroscopic views (namely photos) of the films are collected, and the results are shown in fig. 2, wherein the macroscopic views a to e sequentially belong to the commercial PP film, the comparative example 1, the example 2 and the example 3, and the fact that the commercial PP film and the polyvinylidene fluoride-hexafluoropropylene film of the comparative example 1 have obvious thermal shrinkage can be known from the fig. 2, while the films of the examples 1 to 3 still keep the circles after the heat treatment, which shows that the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films provided by the invention have excellent high temperature resistance.
When the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 2 and the commercial PP film were heat-treated at different temperatures for 0.5h, the thermal shrinkage results are shown in fig. 3, the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 2 has a thermal shrinkage of 0 at 140 ℃, and the commercial PP film has a thermal shrinkage of 17%, while at 150 ℃, the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 2 has a thermal shrinkage of only 2.5%, and the commercial PP film has a thermal shrinkage of 39%.
LiPF at a concentration of 1M6The electrolyte is a test electrolyte, and the contact angles of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in example 1 and the commercial PP film with the electrolyte are respectively tested, so that the results are shown in fig. 4, wherein a is a contact angle test graph of the commercial PP film and the electrolyte, b is a contact angle test graph of the composite film obtained in example 1 and the electrolyte, the contact angle of the composite film obtained in example 1 with the electrolyte is 36 degrees, and the contact angle of the commercial PP film with the electrolyte is 66 ℃, which indicates that the composite film provided in example 1 has better affinity with the electrolyte.
The battery cycle performance of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained in the example 2, the polyvinylidene fluoride-hexafluoropropylene film obtained in the comparative example 1 and a commercial PP film (marked as PP) at 110 ℃ is tested, specifically, the charging and discharging interval is 2.5-3.6V, and the charging and discharging multiplying power is set to be 0.5C. As shown in FIG. 5, it can be seen from FIG. 5 that the specific capacity of the battery of the composite membrane obtained in example 2 is not substantially changed during 25 cycles, while the specific capacity of the battery of PVDF-HFP obtained in comparative example 1 begins to decrease significantly after 15 cycles, and can still maintain 150mAhg-1The commercial PP film is damaged due to no high temperature resistance, and normal charging and discharging can not be carried out.
The ionic conductivity of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite films obtained in examples 1-3, the polyvinylidene fluoride-hexafluoropropylene film obtained in comparative example 1 and the commercial PP film at normal temperature were tested, and the results are shown in fig. 6 and 7, wherein fig. 6 is impedance maps of different diaphragms at room temperature, fig. 7 is the ionic conductivity of each film calculated from fig. 6, it can be known from fig. 6 that the slopes of the impedance curves of the composite films obtained in examples 1-3 are all larger than those of the comparative example 1 and the commercial PP film, which shows that the ionic conductivity of the composite films obtained in examples 1-3 is better as the lithium ion diffusion impedance is smaller, and as can be known from fig. 7, the ionic conductivity of the composite films obtained in examples 1-3 is obviously better than that of the comparative example 1 and the commercial PP film.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane is characterized by comprising the components of polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano fibers and dibutyl phthalate.
2. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film according to claim 1, wherein the mass ratio of the polyvinylidene fluoride-hexafluoropropylene, the carboxyl-modified titanium dioxide nanofiber and the dibutyl phthalate is 1: 0.05-0.15: 0.05-0.1.
3. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane according to claim 1, wherein the preparation method of the carboxyl-modified titanium dioxide nanofiber comprises the steps of:
mixing and grinding titanium dioxide nano-fibers and citric acid, dispersing in water, and centrifuging to obtain the carboxyl modified titanium dioxide nano-fibers.
4. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane according to claim 3, wherein a mass ratio of the titanium dioxide nanofibers and the citric acid is 1: 0.5-1.5.
5. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film according to claim 3 or 4, wherein the titanium dioxide nanofibers have a diameter of 50 to 300nm and a length of 1 to 100 μm.
6. The polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane according to any one of claims 1 to 4, wherein the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane has a porosity of 50 to 70% and a pore diameter of 0.5 to 10 μm.
7. A method for preparing a polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane according to any one of claims 1 to 6, comprising the steps of:
mixing polyvinylidene fluoride-hexafluoropropylene, carboxyl modified titanium dioxide nano-fiber, dibutyl phthalate and a solvent to obtain mixed slurry;
coating the mixed slurry to obtain a composite membrane wet membrane;
and soaking the composite membrane wet membrane in a coagulating bath for phase transfer, and then drying to obtain the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane.
8. The method according to claim 7, wherein the solvent is N-methylpyrrolidone.
9. The method according to claim 7, wherein the phase transition temperature is 20 to 40 ℃ and the time is 12 to 24 hours.
10. Use of the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film according to any one of claims 1 to 6 or the polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite film obtained by the preparation method according to any one of claims 7 to 9 as a lithium battery separator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910886256.XA CN110600662A (en) | 2019-09-19 | 2019-09-19 | Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910886256.XA CN110600662A (en) | 2019-09-19 | 2019-09-19 | Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110600662A true CN110600662A (en) | 2019-12-20 |
Family
ID=68861082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910886256.XA Pending CN110600662A (en) | 2019-09-19 | 2019-09-19 | Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110600662A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114079124A (en) * | 2020-08-14 | 2022-02-22 | 中国科学院上海硅酸盐研究所 | Organic-inorganic composite lithium ion battery diaphragm and preparation method thereof |
| WO2022193498A1 (en) * | 2021-03-19 | 2022-09-22 | 万向一二三股份公司 | Method for preparing high-initial-coulombic-efficiency sio/graphite composite negative electrode material |
| CN116435705A (en) * | 2023-06-09 | 2023-07-14 | 苏州精控能源科技有限公司 | High-thermal-stability flame-retardant lithium battery diaphragm, preparation method thereof and lithium battery |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102190839A (en) * | 2010-03-05 | 2011-09-21 | 深圳市比克电池有限公司 | Gel polymer lithium ion battery, porous composite electrode and porous membrane composition |
| CN102311561A (en) * | 2011-04-27 | 2012-01-11 | 扬州斯培德化工有限公司 | Modified titanium dioxide grain, super-hydrophilic transparent thin film and preparation method thereof |
| KR20130099546A (en) * | 2012-02-29 | 2013-09-06 | 제일모직주식회사 | Separator comprising organic and inorganic mixture coating layer containing soluble polyimide and battery using the separator |
| CN103804708A (en) * | 2012-11-14 | 2014-05-21 | 海洋王照明科技股份有限公司 | Poly(vinylidene fluoride-hexafluoropropenyl) gel polymer film as well as preparation and application thereof |
| CN104124418A (en) * | 2014-07-25 | 2014-10-29 | 佛山市盈博莱科技有限公司 | Lithium ion battery diaphragm and preparation method thereof |
| CN104998562A (en) * | 2015-07-15 | 2015-10-28 | 上海交通大学 | Hydrophilic modification method for polytetrafluoroethylene membrane |
| CN105428571A (en) * | 2015-11-06 | 2016-03-23 | 中国第一汽车股份有限公司 | PVDF-HFP based polymer membrane prepared from polydopamine modified ceramic particles and preparation method |
-
2019
- 2019-09-19 CN CN201910886256.XA patent/CN110600662A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102190839A (en) * | 2010-03-05 | 2011-09-21 | 深圳市比克电池有限公司 | Gel polymer lithium ion battery, porous composite electrode and porous membrane composition |
| CN102311561A (en) * | 2011-04-27 | 2012-01-11 | 扬州斯培德化工有限公司 | Modified titanium dioxide grain, super-hydrophilic transparent thin film and preparation method thereof |
| KR20130099546A (en) * | 2012-02-29 | 2013-09-06 | 제일모직주식회사 | Separator comprising organic and inorganic mixture coating layer containing soluble polyimide and battery using the separator |
| CN103804708A (en) * | 2012-11-14 | 2014-05-21 | 海洋王照明科技股份有限公司 | Poly(vinylidene fluoride-hexafluoropropenyl) gel polymer film as well as preparation and application thereof |
| CN104124418A (en) * | 2014-07-25 | 2014-10-29 | 佛山市盈博莱科技有限公司 | Lithium ion battery diaphragm and preparation method thereof |
| CN104998562A (en) * | 2015-07-15 | 2015-10-28 | 上海交通大学 | Hydrophilic modification method for polytetrafluoroethylene membrane |
| CN105428571A (en) * | 2015-11-06 | 2016-03-23 | 中国第一汽车股份有限公司 | PVDF-HFP based polymer membrane prepared from polydopamine modified ceramic particles and preparation method |
Non-Patent Citations (2)
| Title |
|---|
| HAIJUAN LI等: "High Temperature Resistant Separator of PVDF-HFP/DBP/C-TiO2 for Lithium-Ion Batteries", 《MATERIALS》 * |
| 袁艳: "PVDF-HFP基聚合物微孔膜的制备及在锂离子电池中的应用", 《硕士学位论文》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114079124A (en) * | 2020-08-14 | 2022-02-22 | 中国科学院上海硅酸盐研究所 | Organic-inorganic composite lithium ion battery diaphragm and preparation method thereof |
| WO2022193498A1 (en) * | 2021-03-19 | 2022-09-22 | 万向一二三股份公司 | Method for preparing high-initial-coulombic-efficiency sio/graphite composite negative electrode material |
| CN116435705A (en) * | 2023-06-09 | 2023-07-14 | 苏州精控能源科技有限公司 | High-thermal-stability flame-retardant lithium battery diaphragm, preparation method thereof and lithium battery |
| CN116435705B (en) * | 2023-06-09 | 2023-08-15 | 苏州精控能源科技有限公司 | High-thermal-stability flame-retardant lithium battery diaphragm, preparation method thereof and lithium battery |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106159173B (en) | Polymer composite membrane and preparation method thereof, polymer composite membrane prepared by method, gel electrolyte and lithium ion battery | |
| Li et al. | Effects of an electrospun fluorinated poly (ether ether ketone) separator on the enhanced safety and electrochemical properties of lithium ion batteries | |
| WO2016165559A1 (en) | Composite separator and preparation method therefor, and lithium-ion battery | |
| TWI422090B (en) | Organic/inorganic composite separator having morphology gradient, and manufacturing method thereof and electrochemical device containing the same | |
| JP5591704B2 (en) | Batteries having inorganic / organic porous membrane | |
| TWI321860B (en) | Organic/inorganic composite porous film and electrochemical device using the same | |
| WO2016034019A1 (en) | Aqueous polymer and inorganic nanoparticle composite lithium battery separator and preparation method thereof | |
| CN113013549B (en) | Coating material for light-weight lithium ion battery diaphragm, preparation method of coating material and light-weight lithium ion battery composite diaphragm | |
| KR101676688B1 (en) | Micro porous hybrid separator, method for manufacturing the same and electrochemical device containing the same | |
| CN108281705B (en) | Modified nano SiO2Particles, method of preparing the same, and nanofiber membrane, gel electrolyte and lithium metal battery comprising the same | |
| US20140329131A1 (en) | Heat resisting separator having ultrafine fibrous layer and secondary battery having the same | |
| WO2020211621A1 (en) | Porous diaphragm and preparation method therefor, and lithium-ion battery | |
| CN110600662A (en) | Polyvinylidene fluoride-hexafluoropropylene/titanium dioxide composite membrane and preparation method and application thereof | |
| TW201351758A (en) | Isolation film of electrochemical device and manufacturing method thereof | |
| JP2018536261A (en) | Composite film, method for producing the same, and lithium battery having the same | |
| WO2017167195A1 (en) | Non-porous separator and use thereof | |
| KR20140046137A (en) | Manufacturing method of separator of lithium secondary battery and the separator manufactured thereby and the lithium secondary battery having the separator | |
| CN113224466B (en) | Pressure-sensitive polymer modified diaphragm and preparation method and application thereof | |
| WO2023179550A1 (en) | Composite oil-based separator and preparation method therefor, and secondary battery | |
| CN110556496B (en) | High-safety composite diaphragm with high-temperature self-closing function and preparation method thereof | |
| CN111916628A (en) | Lithium ion battery diaphragm and preparation method thereof | |
| CN113812037A (en) | Method of manufacturing separator and separator manufactured thereby | |
| CN109524594A (en) | A kind of application in mesoporous silicon oxide modification nonwoven cloth diaphragm and lithium-sulfur cell | |
| CN206210903U (en) | A kind of battery diaphragm and the lithium rechargeable battery including it | |
| CN110581249A (en) | Polyvinylidene fluoride-hexafluoropropylene/cellulose/titanium dioxide composite membrane and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20191220 |