CN117691301B - Modified polyvinylidene fluoride lithium ion battery diaphragm and preparation method thereof - Google Patents
Modified polyvinylidene fluoride lithium ion battery diaphragm and preparation method thereof Download PDFInfo
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- 239000002033 PVDF binder Substances 0.000 title claims abstract description 147
- 229920002981 polyvinylidene fluoride Polymers 0.000 title claims abstract description 147
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 69
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 title claims abstract description 59
- 238000002360 preparation method Methods 0.000 title claims abstract description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 85
- 239000002041 carbon nanotube Substances 0.000 claims abstract description 27
- 229910021393 carbon nanotube Inorganic materials 0.000 claims abstract description 26
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 24
- XFNJVJPLKCPIBV-UHFFFAOYSA-N trimethylenediamine Chemical compound NCCCN XFNJVJPLKCPIBV-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000010306 acid treatment Methods 0.000 claims abstract description 22
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910002090 carbon oxide Inorganic materials 0.000 claims abstract description 18
- 239000002071 nanotube Substances 0.000 claims abstract description 18
- OWXJKYNZGFSVRC-NSCUHMNNSA-N (e)-1-chloroprop-1-ene Chemical compound C\C=C\Cl OWXJKYNZGFSVRC-NSCUHMNNSA-N 0.000 claims abstract description 16
- ZXLYUNPVVODNRE-UHFFFAOYSA-N 6-ethenyl-1,3,5-triazine-2,4-diamine Chemical compound NC1=NC(N)=NC(C=C)=N1 ZXLYUNPVVODNRE-UHFFFAOYSA-N 0.000 claims abstract description 16
- HQHSMYARHRXIDS-UHFFFAOYSA-N n,n-dimethyl-1-phenylprop-2-en-1-amine Chemical compound CN(C)C(C=C)C1=CC=CC=C1 HQHSMYARHRXIDS-UHFFFAOYSA-N 0.000 claims abstract description 14
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims abstract description 14
- YZBOZNXACBQJHI-UHFFFAOYSA-N 1-dichlorophosphoryloxyethane Chemical compound CCOP(Cl)(Cl)=O YZBOZNXACBQJHI-UHFFFAOYSA-N 0.000 claims abstract description 13
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 claims abstract description 12
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 12
- 235000019400 benzoyl peroxide Nutrition 0.000 claims abstract description 12
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 12
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 72
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 68
- WEVYAHXRMPXWCK-UHFFFAOYSA-N methyl cyanide Natural products CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 64
- 238000002156 mixing Methods 0.000 claims description 57
- 238000003756 stirring Methods 0.000 claims description 57
- 239000008367 deionised water Substances 0.000 claims description 49
- 229910021641 deionized water Inorganic materials 0.000 claims description 49
- 238000001035 drying Methods 0.000 claims description 49
- 238000005406 washing Methods 0.000 claims description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 49
- 238000006243 chemical reaction Methods 0.000 claims description 37
- 239000000243 solution Substances 0.000 claims description 37
- 229910052757 nitrogen Inorganic materials 0.000 claims description 34
- 238000001914 filtration Methods 0.000 claims description 32
- 239000000203 mixture Substances 0.000 claims description 25
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 24
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 claims description 24
- 238000001816 cooling Methods 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 24
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- 230000015572 biosynthetic process Effects 0.000 claims description 11
- 239000011259 mixed solution Substances 0.000 claims description 10
- 238000003825 pressing Methods 0.000 claims description 9
- 238000010791 quenching Methods 0.000 claims description 9
- 230000000171 quenching effect Effects 0.000 claims description 9
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 8
- -1 acetonitrile amine Chemical class 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 8
- 238000001556 precipitation Methods 0.000 claims description 8
- 238000010992 reflux Methods 0.000 claims description 8
- 238000000967 suction filtration Methods 0.000 claims description 8
- 238000009210 therapy by ultrasound Methods 0.000 claims description 8
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 150000002500 ions Chemical class 0.000 abstract description 11
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 abstract description 10
- 239000003063 flame retardant Substances 0.000 abstract description 10
- 230000000977 initiatory effect Effects 0.000 abstract description 4
- 239000007795 chemical reaction product Substances 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 13
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 10
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 238000005457 optimization Methods 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- JYEUMXHLPRZUAT-UHFFFAOYSA-N 1,2,3-triazine Chemical group C1=CN=NN=C1 JYEUMXHLPRZUAT-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical group OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 150000003904 phospholipids Chemical group 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 150000003242 quaternary ammonium salts Chemical group 0.000 description 2
- 150000003254 radicals Chemical class 0.000 description 2
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical compound ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- 241000272168 Laridae Species 0.000 description 1
- 238000005576 amination reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
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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
- 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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- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention discloses a modified polyvinylidene fluoride lithium ion battery diaphragm and a preparation method thereof, and relates to the technical field of battery diaphragms. In the preparation of a modified polyvinylidene fluoride lithium ion battery diaphragm, firstly, a sulfuric acid solution and a nitric acid solution are oxidized for a carbon nanotube to obtain a carbon oxide nanotube, then the carbon oxide nanotube and 1, 3-propylene diamine are reacted to obtain an aminated carbon nanotube, and the aminated carbon nanotube, ethyl dichlorophosphate and 2-vinyl-4, 6-diamino-1, 3, 5-triazine are reacted to obtain a modified carbon nanotube; sequentially reacting the polyvinylidene fluoride after initiation of dibenzoyl peroxide with N, N-dimethyl vinyl benzyl amine and chloropropene to obtain modified polyvinylidene fluoride; and finally, reacting the modified carbon nano tube, the modified polyvinylidene fluoride and sulfolane, and treating the reaction product with an acid treatment solution to prepare the modified polyvinylidene fluoride lithium ion battery diaphragm. The modified polyvinylidene fluoride lithium ion battery diaphragm prepared by the invention has excellent flame retardant property, ion conduction property and mechanical property.
Description
Technical Field
The invention relates to the technical field of battery diaphragms, in particular to a modified polyvinylidene fluoride lithium ion battery diaphragm and a preparation method thereof.
Background
In the new era, the gradual exhaustion of energy and environmental pollution become the most urgent problems facing human beings. Therefore, the development and development of new clean energy sources are particularly critical. In this case, lithium ion batteries have received much attention as a secondary battery having high specific energy, large capacity, long life, and environmental friendliness. Every corner of people's daily life has the figure of lithium cell. In recent years, the amount of lithium ion batteries has been continuously increased, and the use of lithium ion batteries has gradually become the largest secondary battery in the market. Moreover, as the construction speed of new energy automobiles is continuously increased, the application of lithium ion batteries therein is increasing. In addition, in recent years, the application of the device is rapidly expanded to the fields of large-scale power equipment such as energy storage power stations and electric airplanes. In the future, lithium ion batteries will also have a more huge market, expanding continuously in various fields.
The lithium battery separator is a main component in the battery, and has a non-negligible effect although the separator does not undergo any reaction in the battery. As an important component of the lithium ion battery, the lithium battery diaphragm not only needs to separate the direct contact of the positive electrode and the negative electrode, but also prevents the contact short circuit inside the battery; meanwhile, the lithium ion battery provides a channel for free shuttling of lithium ions between the anode and the cathode, so that electrochemical reaction of the lithium ion battery can be carried out. The structure of the diaphragm has great influence on the performance of the lithium ion battery, and the mechanical property, the flame retardant property and the ion conduction property of the common battery diaphragm are poor. Therefore, the modified polyvinylidene fluoride lithium ion battery diaphragm with excellent flame retardant property, ion conduction property and mechanical property is prepared.
Disclosure of Invention
The invention aims to provide a modified polyvinylidene fluoride lithium ion battery diaphragm and a preparation method thereof, which are used for solving the problems in the prior art.
In order to solve the technical problems, the invention provides the following technical scheme:
the modified polyvinylidene fluoride lithium ion battery diaphragm is characterized by being prepared by reacting a modified carbon nano tube, modified polyvinylidene fluoride and sulfolane and then treating the reaction product with an acid treatment solution.
As optimization, the modified carbon nano tube is prepared by oxidizing a carbon nano tube by sulfuric acid solution and nitric acid solution, reacting with 1, 3-propylene diamine to obtain an aminated carbon nano tube, and reacting with ethyl dichlorophosphate and 2-vinyl-4, 6-diamino-1, 3, 5-triazine.
Preferably, the carbon nanotubes are NACO-CNTs, available from New materials Inc. of the family Jiaxing.
As optimization, the modified polyvinylidene fluoride is prepared by sequentially reacting polyvinylidene fluoride after initiation of dibenzoyl peroxide with N, N-dimethyl vinyl benzyl amine and chloropropene.
Optimally, the polyvinylidene fluoride model is 6020, and is obtained from the plastic raw material company of the gull of Dongguan city.
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing (20-30) a sulfuric acid solution with the mass fraction of 70-80% and a nitric acid solution with the mass fraction of 65-75% according to the mass ratio of 1 (6-10), stirring at 100-200 rpm for 4-6 hours, performing ultrasonic dispersion for 2-4 hours, adding deionized water with the mass of 50-70 times of that of the carbon nanotubes, standing for 8-12 hours, filtering with a microporous filter membrane with the aperture of 210-230 nm, washing with deionized water for 3-5 times, and drying at 55-65 ℃ for 6-8 hours to obtain oxidized carbon nanotubes; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methylpyrrolidone according to the mass ratio of 1 (1-3) (20-30), stirring for 20-40 min at the temperature of 20-30 ℃ and at the speed of 300-500 rpm in a nitrogen environment, heating to 50-70 ℃ for reacting for 1-3 h, cooling to room temperature, filtering, respectively washing with absolute ethyl alcohol and deionized water for 3-5 times, and drying at the temperature of 35-45 ℃ for 10-12 h to obtain the aminated carbon nanotubes; uniformly mixing (1-1.6): (2-4): (0.5-0.8): (10-20) of an aminated carbon nanotube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine in a mass ratio of 1 (1-1.6), stirring and reacting for 1-3 hours at 65-75 ℃ and 100-200 rpm, heating to 75-85 ℃ for continuous reaction for 10-12 hours, standing and cooling to room temperature, filtering, washing for 3-5 times by absolute ethyl alcohol, and drying for 10-14 hours at 70-90 ℃ to obtain a modified carbon nanotube;
(2) Uniformly mixing N, N-dimethylvinylbenzyl amine and N, N-dimethylformamide according to the mass ratio of 1 (20-30), and stirring for 10-30 min at 200-300 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to the mass ratio of 1 (14-16), stirring for 20-40 min at 45-55 ℃ at 100-200 rpm, heating to 65-75 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.04-0.06 times that of the polyvinylidene fluoride, continuously stirring for 20-40 min, uniformly dripping a mixed solution with the mass of 4-6 times that of the polyvinylidene fluoride in 10-30 min, continuously reacting for 7-9 h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 24-26 times that of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 3-5 times with deionized water, and drying for 8-10 h at 40-60 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1 (1-1.2) (20-30), carrying out reflux reaction for 20-24 hours at 80-90 ℃ and 100-200 rpm, carrying out suction filtration while the mixture is hot, washing the mixture for 3-5 times with acetonitrile, and drying the mixture at 40-50 ℃ for 6-8 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution from a hydrochloric acid aqueous solution with the pH value of 4.5-5.0 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing (12-16) modified polyvinylidene fluoride, modified carbon nano tubes and sulfolane according to the mass ratio of 1 (2-3), stirring for 3-5 hours at 175-185 ℃ and 800-1000 rpm in a nitrogen environment, quenching and curing for 2-4 hours in liquid nitrogen, pressing for 10-12 hours at 170-190 ℃ and 3-5 MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 22-26 hours at 20-30 ℃, immersing in acid treatment liquid for ultrasonic treatment for 10-30 min, washing for 3-5 times by using deionized water, and drying for 6-8 hours at 50-60 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
As an optimization, the reaction equation of the aminated carbon nanotube in the step (1) is as follows:
。
as an optimization, the reaction equation of the modified carbon nanotube in the step (1) is as follows:
。
as an optimization, the reaction equation of the pre-modified polyvinylidene fluoride in the step (2) is as follows:
。
as an optimization, the reaction equation of the modified polyvinylidene fluoride in the step (2) is as follows:
。
compared with the prior art, the invention has the following beneficial effects:
in the preparation of a modified polyvinylidene fluoride lithium ion battery diaphragm, firstly, a sulfuric acid solution and a nitric acid solution are oxidized for a carbon nanotube to obtain a carbon oxide nanotube, then the carbon oxide nanotube and 1, 3-propylene diamine are reacted to obtain an aminated carbon nanotube, and the aminated carbon nanotube, ethyl dichlorophosphate and 2-vinyl-4, 6-diamino-1, 3, 5-triazine are reacted to obtain a modified carbon nanotube; sequentially reacting the polyvinylidene fluoride after initiation of dibenzoyl peroxide with N, N-dimethyl vinyl benzyl amine and chloropropene to obtain modified polyvinylidene fluoride; and finally, reacting the modified carbon nano tube, the modified polyvinylidene fluoride and sulfolane, and treating the reaction product with an acid treatment solution to prepare the modified polyvinylidene fluoride lithium ion battery diaphragm.
Firstly, oxidizing a sulfuric acid solution and a nitric acid solution for a carbon nano tube to obtain an oxidized carbon nano tube, then reacting the oxidized carbon nano tube with 1, 3-propylene diamine to obtain an aminated carbon nano tube, and reacting the aminated carbon nano tube, ethyl dichlorophosphate and 2-vinyl-4, 6-diamino-1, 3, 5-triazine to obtain a modified carbon nano tube; amination is carried out on the surface of the carbon nano tube, ethylene dichloride and 2-vinyl-4, 6-diamino-1, 3, 5-triazine are grafted, phosphorus element capturing free radical is introduced to promote the formation of a carbon layer so as to isolate heat and oxygen, and the flame retardant effect of the modified polyvinylidene fluoride lithium ion battery diaphragm is improved; meanwhile, the introduced triazine structure can generate nonflammable nitrogen-containing gas, can absorb heat, dilute oxygen concentration, reduce combustion temperature and further improve the flame retardant property of the modified polyvinylidene fluoride lithium ion battery diaphragm; the grafted 2-vinyl-4, 6-diamino-1, 3, 5-triazine has a carbon-carbon double bond structure, can carry out polymerization reaction with the carbon-carbon double bond on the modified polyvinylidene fluoride, and enhances the mechanical property of the modified polyvinylidene fluoride lithium ion battery diaphragm.
Secondly, sequentially reacting the polyvinylidene fluoride after initiation of dibenzoyl peroxide with N, N-dimethyl vinyl benzyl amine and chloropropene to obtain modified polyvinylidene fluoride; finally, after the modified carbon nano tube, the modified polyvinylidene fluoride and sulfolane react, treating the mixture with an acid treatment solution to prepare a modified polyvinylidene fluoride lithium ion battery diaphragm; the polyvinylidene fluoride is sequentially reacted with N, N-dimethyl vinyl benzyl amine and chloropropene to form a quaternary ammonium salt structure, so that the ion conduction capacity of the modified polyvinylidene fluoride lithium ion battery diaphragm can be improved; meanwhile, the grafted chloropropene has a carbon-carbon double bond structure, can carry out polymerization reaction with carbon-carbon double bonds on the modified carbon nano tube, and enhances the mechanical properties of the modified polyvinylidene fluoride lithium ion battery diaphragm; sulfolane is used as a pore-forming agent to form rich pore structures on the modified polyvinylidene fluoride lithium ion battery diaphragm, so that the ion conduction capacity of the modified polyvinylidene fluoride lithium ion battery diaphragm is enhanced; and (3) acidolysis of the phospholipid structure on the modified carbon nanotube into a phosphoric acid structure by using an acid treatment liquid, so that the electrostatic bonding capability between the modified carbon nanotube and the modified polyvinylidene fluoride is enhanced, and the mechanical property and the ion conductivity of the modified polyvinylidene fluoride lithium ion battery diaphragm are further enhanced.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to more clearly illustrate the method provided by the invention, the following examples are used for describing the detailed description, and the test method of each index of the modified polyvinylidene fluoride lithium ion battery diaphragm manufactured in the following examples is as follows:
flame retardant properties: the modified polyvinylidene fluoride lithium ion battery separator obtained in each example was tested for limiting oxygen index according to GB/T2406 with the comparative example.
Ion conductivity properties: the modified polyvinylidene fluoride lithium ion battery diaphragm obtained in each example and the comparative example material are respectively cut into circular sheets with the diameter of 1cm, the circular sheets are placed between two electrodes of a stainless steel battery model, a die is clamped, then the battery device is placed into a temperature-controllable oven, alternating current impedance (R) of the film is measured at 30 ℃ by a double electrode method, ion conductivity (sigma=thickness/R area) is calculated, and ion conductivity is judged.
Mechanical properties: the modified polyvinylidene fluoride lithium ion battery diaphragm obtained in each example and the comparative example material are cut into dumbbell shapes with the length of 6mm and the width of 4mm, and are stretched under the conditions of 30 ℃ and the stretching rate of 5mm/min, and the tensile strength is tested to judge the mechanical properties.
Example 1
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 70% and a nitric acid solution with the mass fraction of 65% according to the mass ratio of 1:20:6, stirring at 100rpm for 6 hours, then performing ultrasonic dispersion for 4 hours, adding deionized water with the mass 50 times of that of the carbon nano tube, standing for 8 hours, filtering by using a microporous filter membrane with the aperture of 210nm, washing for 3 times by using the deionized water, and drying at 55 ℃ for 8 hours to obtain the carbon oxide nano tube; uniformly mixing the carbon oxide nano tube, the 1, 3-propylene diamine and the N-methyl pyrrolidone according to the mass ratio of 1:1:20, stirring for 40min at 20 ℃ and 300rpm in a nitrogen environment, heating to 50 ℃ for reaction for 3h, cooling to room temperature, filtering, respectively washing for 3 times by using absolute ethyl alcohol and deionized water, and drying for 12h at 35 ℃ to obtain the aminated carbon nano tube; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1:2:0.5:10, stirring at 100rpm for reaction for 3 hours at 65 ℃, heating to 75 ℃ for continuous reaction for 12 hours, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 3 times, and drying at 70 ℃ for 14 hours to obtain a modified carbon nano tube;
(2) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to the mass ratio of 1:20, and stirring for 30min at 200 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:14, stirring for 40min at 45 ℃ and 100rpm, heating to 65 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.04 times of the polyvinylidene fluoride, continuously stirring for 40min, uniformly dripping mixed liquid with the mass of 4 times of the polyvinylidene fluoride in 10min, continuously reacting for 9h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 24 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 3 times by deionized water, and drying for 10h at 40 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1:20, carrying out reflux reaction for 24 hours at 80 ℃ and 100rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 3 times, and drying the mixture at 40 ℃ for 8 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution from an aqueous hydrochloric acid solution with the pH of 4.5 and N, N-dimethylformamide according to the volume ratio of 1:1; uniformly mixing the modified polyvinylidene fluoride, the modified carbon nano tube and sulfolane according to the mass ratio of 1:2:12, stirring for 5 hours at 175 ℃ and 800rpm in a nitrogen environment, quenching and curing for 2 hours in liquid nitrogen, pressing for 12 hours at 170 ℃ and 3MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 26 hours at 20 ℃, immersing in acid treatment liquid for ultrasonic treatment for 10 minutes, washing for 3 times by using deionized water, and drying for 8 hours at 50 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Example 2
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 75% and a nitric acid solution with the mass fraction of 70% according to the mass ratio of 1:25:8, stirring at 150rpm for 5 hours, then performing ultrasonic dispersion for 3 hours, adding deionized water with the mass of 60 times of that of the carbon nano tube, standing for 10 hours, filtering by using a microporous filter membrane with the aperture of 220nm, washing for 4 times by using the deionized water, and drying at 60 ℃ for 7 hours to obtain the carbon oxide nano tube; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methyl pyrrolidone according to a mass ratio of 1:2:25, stirring for 30min at 25 ℃ under a nitrogen environment, heating to 60 ℃ for reaction for 2h, cooling to room temperature, filtering, washing with absolute ethyl alcohol and deionized water for 5 times respectively, and drying at 40 ℃ for 11h to obtain the aminated carbon nanotubes; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1.3:3:0.75:15, stirring at 70 ℃ and 150rpm for reaction for 2 hours, heating to 80 ℃ for continuous reaction for 11 hours, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 4 times, and drying at 80 ℃ for 12 hours to obtain a modified carbon nano tube;
(2) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to a mass ratio of 1:25, and stirring for 20min at 250 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:15, stirring for 30min at 50 ℃ and 150rpm, heating to 70 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.05 times of the polyvinylidene fluoride, continuously stirring for 30min, uniformly dripping mixed liquid with the mass of 5 times of the polyvinylidene fluoride in 20min, continuously reacting for 8h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 25 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 4 times by deionized water, and drying for 9h at 50 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1.1:25, carrying out reflux reaction for 22 hours at 85 ℃ and 150rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 4 times, and drying the mixture at 45 ℃ for 7 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution by using a hydrochloric acid aqueous solution with the pH of 4.75 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing the modified polyvinylidene fluoride, the modified carbon nano tube and sulfolane according to the mass ratio of 1:2.5:14, stirring for 4 hours at 180 ℃ and 900rpm in a nitrogen environment, quenching and curing for 3 hours in liquid nitrogen, pressing for 11 hours at 180 ℃ and 4MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 24 hours at 25 ℃, immersing in acid treatment liquid for ultrasonic treatment for 20 minutes, washing for 4 times by using deionized water, and drying for 7 hours at 55 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Example 3
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 80% and a nitric acid solution with the mass fraction of 75% according to the mass ratio of 1:30:10, stirring at 200rpm for 4 hours, then performing ultrasonic dispersion for 2 hours, adding deionized water with the mass 70 times of that of the carbon nano tube, standing for 12 hours, filtering by using a microporous filter membrane with the aperture of 230nm, washing for 5 times by using the deionized water, and drying at 65 ℃ for 6 hours to obtain the carbon oxide nano tube; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methyl pyrrolidone according to a mass ratio of 1:3:30, stirring for 20min at 500rpm at 30 ℃ under a nitrogen environment, heating to 70 ℃ for reaction for 1h, cooling to room temperature, filtering, washing with absolute ethyl alcohol and deionized water for 5 times respectively, and drying at 45 ℃ for 10h to obtain the aminated carbon nanotubes; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1.6:4:0.8:20, stirring at 200rpm at 75 ℃ for reaction for 1h, heating to 85 ℃ for continuous reaction for 10h, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 5 times, and drying at 90 ℃ for 10h to obtain a modified carbon nano tube;
(2) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to a mass ratio of 1:30, and stirring for 10min at 300 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:16, stirring for 20min at 55 ℃ and 200rpm, heating to 75 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.06 times of the polyvinylidene fluoride, continuously stirring for 20min, uniformly dripping mixed liquid with the mass of 6 times of the polyvinylidene fluoride in 30min, continuously reacting for 7h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 26 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 5 times by deionized water, and drying for 8h at 60 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1.2:30, carrying out reflux reaction for 20 hours at 90 ℃ and 200rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 5 times, and drying the mixture at 50 ℃ for 6 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution from an aqueous hydrochloric acid solution with the pH of 5.0 and N, N-dimethylformamide according to the volume ratio of 1:1; uniformly mixing the modified polyvinylidene fluoride, the modified carbon nano tube and sulfolane according to the mass ratio of 1:3:16, stirring for 3 hours at 185 ℃ and 1000rpm in a nitrogen environment, quenching and solidifying for 4 hours in liquid nitrogen, pressing for 10 hours at 190 ℃ and 5MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 22 hours at 30 ℃, immersing in acid treatment liquid for ultrasonic treatment for 30 minutes, washing for 5 times by using deionized water, and drying for 6 hours at 60 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Comparative example 1
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to a mass ratio of 1:25, and stirring for 20min at 250 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:15, stirring for 30min at 50 ℃ and 150rpm, heating to 70 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.05 times of the polyvinylidene fluoride, continuously stirring for 30min, uniformly dripping mixed liquid with the mass of 5 times of the polyvinylidene fluoride in 20min, continuously reacting for 8h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 25 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 4 times by deionized water, and drying for 9h at 50 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1.1:25, carrying out reflux reaction for 22 hours at 85 ℃ and 150rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 4 times, and drying the mixture at 45 ℃ for 7 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution by using a hydrochloric acid aqueous solution with the pH of 4.75 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing the modified polyvinylidene fluoride, the carbon nano tube and sulfolane according to the mass ratio of 1:2.5:14, stirring for 4 hours at 180 ℃ at 900rpm in a nitrogen environment, quenching and curing for 3 hours in liquid nitrogen, pressing for 11 hours at 180 ℃ at 4MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 24 hours at 25 ℃, immersing in acid treatment liquid for ultrasonic treatment for 20 minutes, washing for 4 times by using deionized water, and drying for 7 hours at 55 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Comparative example 2
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 75% and a nitric acid solution with the mass fraction of 70% according to the mass ratio of 1:25:8, stirring at 150rpm for 5 hours, then performing ultrasonic dispersion for 3 hours, adding deionized water with the mass of 60 times of that of the carbon nano tube, standing for 10 hours, filtering by using a microporous filter membrane with the aperture of 220nm, washing for 4 times by using the deionized water, and drying at 60 ℃ for 7 hours to obtain the carbon oxide nano tube; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methyl pyrrolidone according to a mass ratio of 1:2:25, stirring for 30min at 25 ℃ under a nitrogen environment, heating to 60 ℃ for reaction for 2h, cooling to room temperature, filtering, washing with absolute ethyl alcohol and deionized water for 5 times respectively, and drying at 40 ℃ for 11h to obtain the aminated carbon nanotubes; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1.3:3:0.75:15, stirring at 70 ℃ and 150rpm for reaction for 2 hours, heating to 80 ℃ for continuous reaction for 11 hours, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 4 times, and drying at 80 ℃ for 12 hours to obtain a modified carbon nano tube;
(2) Preparing an acid treatment solution by using a hydrochloric acid aqueous solution with the pH of 4.75 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing polyvinylidene fluoride, a modified carbon nano tube and sulfolane according to the mass ratio of 1:2.5:14, stirring for 4 hours at 180 ℃ and 900rpm in a nitrogen environment, quenching and curing for 3 hours in liquid nitrogen, pressing for 11 hours at 180 ℃ and 4MPa by a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 24 hours at 25 ℃, immersing in acid treatment liquid for ultrasonic treatment for 20 minutes, washing for 4 times by using deionized water, and drying for 7 hours at 55 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Comparative example 3
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 75% and a nitric acid solution with the mass fraction of 70% according to the mass ratio of 1:25:8, stirring at 150rpm for 5 hours, then performing ultrasonic dispersion for 3 hours, adding deionized water with the mass of 60 times of that of the carbon nano tube, standing for 10 hours, filtering by using a microporous filter membrane with the aperture of 220nm, washing for 4 times by using the deionized water, and drying at 60 ℃ for 7 hours to obtain the carbon oxide nano tube; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methyl pyrrolidone according to a mass ratio of 1:2:25, stirring for 30min at 25 ℃ under a nitrogen environment, heating to 60 ℃ for reaction for 2h, cooling to room temperature, filtering, washing with absolute ethyl alcohol and deionized water for 5 times respectively, and drying at 40 ℃ for 11h to obtain the aminated carbon nanotubes; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1.3:3:0.75:15, stirring at 70 ℃ and 150rpm for reaction for 2 hours, heating to 80 ℃ for continuous reaction for 11 hours, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 4 times, and drying at 80 ℃ for 12 hours to obtain a modified carbon nano tube;
(2) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to a mass ratio of 1:25, and stirring for 20min at 250 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:15, stirring for 30min at 50 ℃ and 150rpm, heating to 70 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.05 times of the polyvinylidene fluoride, continuously stirring for 30min, uniformly dripping mixed liquid with the mass of 5 times of the polyvinylidene fluoride in 20min, continuously reacting for 8h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 25 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 4 times by deionized water, and drying for 9h at 50 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1.1:25, carrying out reflux reaction for 22 hours at 85 ℃ and 150rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 4 times, and drying the mixture at 45 ℃ for 7 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution by using a hydrochloric acid aqueous solution with the pH of 4.75 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing the modified polyvinylidene fluoride and the modified carbon nano tube according to the mass ratio of 1:2.5, stirring for 4 hours at 180 ℃ and 900rpm in a nitrogen environment, quenching and solidifying for 3 hours in liquid nitrogen, pressing for 11 hours at 180 ℃ and 4MPa by using a flat vulcanizing machine, taking out and immersing in an acid treatment liquid for ultrasonic treatment for 20 minutes after film formation, washing for 4 times by using deionized water, and drying for 7 hours at 55 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Comparative example 4
The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm comprises the following preparation steps:
(1) Uniformly mixing a carbon nano tube, a sulfuric acid solution with the mass fraction of 75% and a nitric acid solution with the mass fraction of 70% according to the mass ratio of 1:25:8, stirring at 150rpm for 5 hours, then performing ultrasonic dispersion for 3 hours, adding deionized water with the mass of 60 times of that of the carbon nano tube, standing for 10 hours, filtering by using a microporous filter membrane with the aperture of 220nm, washing for 4 times by using the deionized water, and drying at 60 ℃ for 7 hours to obtain the carbon oxide nano tube; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methyl pyrrolidone according to a mass ratio of 1:2:25, stirring for 30min at 25 ℃ under a nitrogen environment, heating to 60 ℃ for reaction for 2h, cooling to room temperature, filtering, washing with absolute ethyl alcohol and deionized water for 5 times respectively, and drying at 40 ℃ for 11h to obtain the aminated carbon nanotubes; uniformly mixing an aminated carbon nano tube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine according to the mass ratio of 1:1.3:3:0.75:15, stirring at 70 ℃ and 150rpm for reaction for 2 hours, heating to 80 ℃ for continuous reaction for 11 hours, standing, cooling to room temperature, filtering, washing with absolute ethyl alcohol for 4 times, and drying at 80 ℃ for 12 hours to obtain a modified carbon nano tube;
(2) Uniformly mixing N, N-dimethyl vinyl benzyl amine and N, N-dimethyl formamide according to a mass ratio of 1:25, and stirring for 20min at 250 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to a mass ratio of 1:15, stirring for 30min at 50 ℃ and 150rpm, heating to 70 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.05 times of the polyvinylidene fluoride, continuously stirring for 30min, uniformly dripping mixed liquid with the mass of 5 times of the polyvinylidene fluoride in 20min, continuously reacting for 8h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 25 times of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 4 times by deionized water, and drying for 9h at 50 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1:1.1:25, carrying out reflux reaction for 22 hours at 85 ℃ and 150rpm, carrying out suction filtration while the mixture is hot, washing the mixture with acetonitrile for 4 times, and drying the mixture at 45 ℃ for 7 hours to obtain modified polyvinylidene fluoride;
(3) Uniformly mixing the modified polyvinylidene fluoride, the modified carbon nano tube and sulfolane according to the mass ratio of 1:2.5:14, stirring for 4 hours at 180 ℃ and 900rpm in a nitrogen environment, quenching and curing for 3 hours in liquid nitrogen, pressing for 11 hours at 180 ℃ and 4MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 24 hours at 25 ℃, washing for 4 times by using deionized water, and drying for 7 hours at 55 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
Effect example
The following table 1 shows the analysis results of flame retardant property, ion conductive property and mechanical property of the modified polyvinylidene fluoride lithium ion battery separator adopting examples 1 to 3 and comparative examples 1 to 4 of the present invention.
，
From the comparison of experimental data of examples 1-3 and comparative examples 1-4 in Table 1, it can be found that the modified polyvinylidene fluoride lithium ion battery separator prepared by the invention has good flame retardant property, ion conductive property and mechanical property.
By comparison, examples 1, 2 and 3 have high limiting oxygen index and tensile strength compared with comparative example 1, which shows that the surface of the carbon nano tube is aminated, grafted with ethyl dichlorophosphate and 2-vinyl-4, 6-diamino-1, 3, 5-triazine, and phosphorus element is introduced to capture free radicals so as to promote the formation of a carbon layer, thereby isolating heat and oxygen and improving the flame retardant effect of the modified polyvinylidene fluoride lithium ion battery diaphragm; meanwhile, the introduced triazine structure can generate nonflammable nitrogen-containing gas, can absorb heat, dilute oxygen concentration, reduce combustion temperature and further improve the flame retardant property of the modified polyvinylidene fluoride lithium ion battery diaphragm; the grafted 2-vinyl-4, 6-diamino-1, 3, 5-triazine has a carbon-carbon double bond structure, can carry out polymerization reaction with the carbon-carbon double bond on the modified polyvinylidene fluoride, and enhances the mechanical property of the modified polyvinylidene fluoride lithium ion battery diaphragm.
By comparison, examples 1, 2 and 3 have high ionic conductivity and tensile strength compared with comparative example 2, which shows that polyvinylidene fluoride reacts with N, N-dimethyl vinyl benzyl amine and chloropropene in sequence to form a quaternary ammonium salt structure, so that the ionic conductivity of the modified polyvinylidene fluoride lithium ion battery diaphragm can be improved; meanwhile, the grafted chloropropene has a carbon-carbon double bond structure, can carry out polymerization reaction with the carbon-carbon double bond on the modified carbon nano tube, and enhances the mechanical property of the modified polyvinylidene fluoride lithium ion battery diaphragm.
By comparison, examples 1, 2 and 3 have high ionic conductivity compared with comparative example 3, which shows that sulfolane is used as a pore-forming agent to form rich pore structures on the modified polyvinylidene fluoride lithium ion battery diaphragm, so that the ionic conductivity of the modified polyvinylidene fluoride lithium ion battery diaphragm is improved.
By comparison, examples 1, 2 and 3 and comparative example 4 have high ionic conductivity and tensile strength, which illustrates that acidolysis of the phospholipid structure on the modified carbon nanotube into a phosphoric acid structure by using an acid treatment solution enhances the electrostatic bonding capability between the modified carbon nanotube and the modified polyvinylidene fluoride, and further enhances the mechanical property and the ionic conductivity of the modified polyvinylidene fluoride lithium ion battery separator.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (6)
1. The preparation method of the modified polyvinylidene fluoride lithium ion battery diaphragm is characterized by comprising the following preparation steps:
(1) Uniformly mixing (20-30) a sulfuric acid solution with the mass fraction of 70-80% and a nitric acid solution with the mass fraction of 65-75% according to the mass ratio of 1 (6-10), stirring at 100-200 rpm for 4-6 hours, performing ultrasonic dispersion for 2-4 hours, adding deionized water with the mass of 50-70 times of that of the carbon nanotubes, standing for 8-12 hours, filtering with a microporous filter membrane with the aperture of 210-230 nm, washing with deionized water for 3-5 times, and drying at 55-65 ℃ for 6-8 hours to obtain oxidized carbon nanotubes; uniformly mixing carbon oxide nanotubes, 1, 3-propylene diamine and N-methylpyrrolidone according to the mass ratio of 1 (1-3) (20-30), stirring for 20-40 min at the temperature of 20-30 ℃ and at the speed of 300-500 rpm in a nitrogen environment, heating to 50-70 ℃ for reacting for 1-3 h, cooling to room temperature, filtering, respectively washing with absolute ethyl alcohol and deionized water for 3-5 times, and drying at the temperature of 35-45 ℃ for 10-12 h to obtain the aminated carbon nanotubes; uniformly mixing (1-1.6): (2-4): (0.5-0.8): (10-20) of an aminated carbon nanotube, ethyl dichlorophosphate, 2-vinyl-4, 6-diamino-1, 3, 5-triazine, triethylamine and acetonitrile amine in a mass ratio of 1 (1-1.6), stirring and reacting for 1-3 hours at 65-75 ℃ and 100-200 rpm, heating to 75-85 ℃ for continuous reaction for 10-12 hours, standing and cooling to room temperature, filtering, washing for 3-5 times by absolute ethyl alcohol, and drying for 10-14 hours at 70-90 ℃ to obtain a modified carbon nanotube;
(2) Uniformly mixing N, N-dimethylvinylbenzyl amine and N, N-dimethylformamide according to the mass ratio of 1 (20-30), and stirring for 10-30 min at 200-300 to obtain a mixed solution; uniformly mixing polyvinylidene fluoride and N, N-dimethylformamide according to the mass ratio of 1 (14-16), stirring for 20-40 min at 45-55 ℃ at 100-200 rpm, heating to 65-75 ℃ in a nitrogen environment, adding dibenzoyl peroxide with the mass of 0.04-0.06 times that of the polyvinylidene fluoride, continuously stirring for 20-40 min, uniformly dripping a mixed solution with the mass of 4-6 times that of the polyvinylidene fluoride in 10-30 min, continuously reacting for 7-9 h, cooling to room temperature, adding absolute ethyl alcohol with the mass of 24-26 times that of the polyvinylidene fluoride, standing until the precipitation mass is unchanged, filtering, washing for 3-5 times with deionized water, and drying for 8-10 h at 40-60 ℃ to obtain the pre-modified polyvinylidene fluoride; uniformly mixing pre-modified polyvinylidene fluoride, chloropropene and acetonitrile according to the mass ratio of 1 (1-1.2) (20-30), carrying out reflux reaction for 20-24 hours at 80-90 ℃ and 100-200 rpm, carrying out suction filtration while the mixture is hot, washing the mixture for 3-5 times with acetonitrile, and drying the mixture at 40-50 ℃ for 6-8 hours to obtain modified polyvinylidene fluoride;
(3) Preparing an acid treatment solution from a hydrochloric acid aqueous solution with the pH value of 4.5-5.0 and N, N-dimethylformamide according to a volume ratio of 1:1; uniformly mixing (12-16) modified polyvinylidene fluoride, modified carbon nano tubes and sulfolane according to the mass ratio of 1 (2-3), stirring for 3-5 hours at 175-185 ℃ and 800-1000 rpm in a nitrogen environment, quenching and curing for 2-4 hours in liquid nitrogen, pressing for 10-12 hours at 170-190 ℃ and 3-5 MPa by using a flat vulcanizing machine, taking out and immersing in deionized water after film formation, standing for 22-26 hours at 20-30 ℃, immersing in acid treatment liquid for ultrasonic treatment for 10-30 min, washing for 3-5 times by using deionized water, and drying for 6-8 hours at 50-60 ℃ to obtain the modified polyvinylidene fluoride lithium ion battery diaphragm.
2. The method for preparing a modified polyvinylidene fluoride lithium ion battery separator according to claim 1, wherein the reaction equation of the aminated carbon nanotubes in the step (1) is as follows:
。
3. the method for preparing a modified polyvinylidene fluoride lithium ion battery separator according to claim 1, wherein the reaction equation of the modified carbon nanotubes in the step (1) is as follows:
。
4. the method for preparing a modified polyvinylidene fluoride lithium ion battery separator according to claim 1, wherein the reaction equation of the pre-modified polyvinylidene fluoride in the step (2) is as follows:
。
5. the method for preparing a modified polyvinylidene fluoride lithium ion battery separator according to claim 1, wherein the reaction equation of the modified polyvinylidene fluoride in the step (2) is as follows:
。
6. a modified polyvinylidene fluoride lithium ion battery separator prepared by the preparation method of the modified polyvinylidene fluoride lithium ion battery separator according to any one of claims 1-5.
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