CN115850863A - Polypropylene film, preparation method thereof, composite current collector and application - Google Patents
Polypropylene film, preparation method thereof, composite current collector and application Download PDFInfo
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- CN115850863A CN115850863A CN202211656040.2A CN202211656040A CN115850863A CN 115850863 A CN115850863 A CN 115850863A CN 202211656040 A CN202211656040 A CN 202211656040A CN 115850863 A CN115850863 A CN 115850863A
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- -1 Polypropylene Polymers 0.000 title claims abstract description 226
- 239000004743 Polypropylene Substances 0.000 title claims abstract description 221
- 229920001155 polypropylene Polymers 0.000 title claims abstract description 221
- 239000002131 composite material Substances 0.000 title claims abstract description 73
- 238000002360 preparation method Methods 0.000 title abstract description 22
- 239000002070 nanowire Substances 0.000 claims abstract description 101
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims abstract description 58
- 239000002994 raw material Substances 0.000 claims abstract description 29
- 229910052588 hydroxylapatite Inorganic materials 0.000 claims abstract description 24
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical compound [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 claims abstract description 24
- VTGNXADCFUDPLG-UHFFFAOYSA-N O(O)O.[Cu] Chemical compound O(O)O.[Cu] VTGNXADCFUDPLG-UHFFFAOYSA-N 0.000 claims abstract description 8
- SEFNWANLZIRUGT-UHFFFAOYSA-N [Gd].OOO Chemical compound [Gd].OOO SEFNWANLZIRUGT-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims description 45
- 239000002184 metal Substances 0.000 claims description 45
- 239000010410 layer Substances 0.000 claims description 44
- 238000000034 method Methods 0.000 claims description 28
- 239000011241 protective layer Substances 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 239000000155 melt Substances 0.000 claims description 15
- 239000012528 membrane Substances 0.000 claims description 15
- 238000009826 distribution Methods 0.000 claims description 14
- 238000009998 heat setting Methods 0.000 claims description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 12
- 238000005266 casting Methods 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 10
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 7
- 239000012768 molten material Substances 0.000 claims description 7
- 230000001360 synchronised effect Effects 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 4
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 3
- 239000005751 Copper oxide Substances 0.000 claims description 3
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000002134 carbon nanofiber Substances 0.000 claims description 3
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 3
- 239000002041 carbon nanotube Substances 0.000 claims description 3
- 229910000423 chromium oxide Inorganic materials 0.000 claims description 3
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 3
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 3
- JGDFBJMWFLXCLJ-UHFFFAOYSA-N copper chromite Chemical compound [Cu]=O.[Cu]=O.O=[Cr]O[Cr]=O JGDFBJMWFLXCLJ-UHFFFAOYSA-N 0.000 claims description 3
- 229910000431 copper oxide Inorganic materials 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 3
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 3
- 239000002096 quantum dot Substances 0.000 claims description 3
- 229910001120 nichrome Inorganic materials 0.000 claims 1
- 229920000642 polymer Polymers 0.000 description 15
- 239000000853 adhesive Substances 0.000 description 10
- 230000001070 adhesive effect Effects 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 8
- 230000002950 deficient Effects 0.000 description 8
- 238000009713 electroplating Methods 0.000 description 8
- 238000001816 cooling Methods 0.000 description 7
- 150000001875 compounds Chemical class 0.000 description 6
- 238000001755 magnetron sputter deposition Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000004804 winding Methods 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 229920006242 ethylene acrylic acid copolymer Polymers 0.000 description 4
- 229920002521 macromolecule Polymers 0.000 description 4
- 238000005240 physical vapour deposition Methods 0.000 description 4
- 238000007738 vacuum evaporation Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 241001391944 Commicarpus scandens Species 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- 230000002457 bidirectional effect Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 229910052809 inorganic oxide Inorganic materials 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910000623 nickel–chromium alloy Inorganic materials 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920006254 polymer film Polymers 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 238000009827 uniform distribution Methods 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000004353 Polyethylene glycol 8000 Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- GEVMESGZABCIMM-UHFFFAOYSA-M [OH-].[Cu+]=O Chemical compound [OH-].[Cu+]=O GEVMESGZABCIMM-UHFFFAOYSA-M 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000001505 atmospheric-pressure chemical vapour deposition Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000007607 die coating method Methods 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000007765 extrusion coating Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- QUQMBZBYZFWOQA-UHFFFAOYSA-M gadolinium(3+) oxygen(2-) hydroxide Chemical compound [OH-].[O-2].[Gd+3] QUQMBZBYZFWOQA-UHFFFAOYSA-M 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- UQBBITJKXYYJPG-UHFFFAOYSA-M hydroxy(oxo)tungsten Chemical compound O[W]=O UQBBITJKXYYJPG-UHFFFAOYSA-M 0.000 description 1
- 238000010952 in-situ formation Methods 0.000 description 1
- 238000009421 internal insulation Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229940085678 polyethylene glycol 8000 Drugs 0.000 description 1
- 235000019446 polyethylene glycol 8000 Nutrition 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
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Abstract
The application relates to a polypropylene film, a preparation method thereof, a composite current collector and application, and belongs to the technical field of batteries. The polypropylene film provided by the application comprises the following raw materials in percentage by mass: 90 to 99.9 percent of polypropylene and 0.1 to 10 percent of hydroxyl-containing sub-nanowire; the hydroxyl-containing sub-nanowire comprises one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire and a copper oxyhydroxide sub-nanowire. The polypropylene film provided by the application can improve the surface adhesion performance and the mechanical property of the polypropylene film.
Description
Technical Field
The application relates to the technical field of batteries, in particular to a polypropylene film, a preparation method thereof, a composite current collector and application.
Background
The composite current collector can be prepared by taking a high-molecular polymer film as a base film and depositing a layer of metal material on the surface of the base film. Compared with the traditional current collector, the composite current collector using the high-molecular polymer film as the base film has the characteristics of low cost, light weight, good internal insulation and the like, so that the cost of the battery can be reduced and the energy density and the safety of the battery can be improved when the composite current collector is applied to the battery.
However, the composite current collector prepared by using the conventional polypropylene film as a base film has the following problems: (1) because the polypropylene film has weaker polarity and lower surface tension and the affinity between the polypropylene film with low surface tension and the metal layer with high surface tension is poorer, the adhesion between the two interfaces is lower and the combination is not firm, namely, the problem of poor surface adhesion performance of the polypropylene film exists. (2) The polypropylene film has low mechanical property indexes such as elastic modulus, tensile strength and the like, so that the mechanical property of the polypropylene film is relatively poor, and the problems that the film is easy to break, the yield is reduced and the mechanical property of the prepared composite current collector is poor are caused in the preparation process of the composite current collector.
Disclosure of Invention
Based on the above, it is necessary to provide a polypropylene film, a preparation method thereof, a composite current collector and applications thereof, so as to improve the surface adhesion property and the mechanical property of the polypropylene film.
The first aspect of the present application provides a polypropylene film, which comprises the following raw materials by mass: 90 to 99.9 percent of polypropylene and 0.1 to 10 percent of hydroxyl-containing sub-nanowire;
the hydroxyl-containing sub-nanowire comprises one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire and a copper oxyhydroxide sub-nanowire.
In some embodiments, the hydroxyl-containing sub-nanowires have a diameter of less than 1nm and an aspect ratio of greater than or equal to 10.
In some embodiments, the hydroxyl-containing nanowires have a diameter of less than 1nm, and the hydroxyl-containing nanowires have an aspect ratio of 10 to 1000.
In some embodiments, the polypropylene has a melt index of 3g/10min to 4g/10min at 230 ℃ under a 2.16kg load.
In some embodiments, the polypropylene has a molecular weight distribution index of 4.5 to 5.3.
In some embodiments, the polypropylene has an isotacticity greater than or equal to 96%.
A second aspect of the present application provides a method of producing a polypropylene film as described in the first aspect of the present application, comprising the steps of:
mixing the polypropylene and the hydroxyl-containing sub-nanowires, melting, and extruding a molten material;
and sequentially carrying out casting sheet treatment and biaxial tension treatment on the molten material.
In some embodiments, the temperature of the melting is from 200 ℃ to 260 ℃.
In some embodiments, the biaxial stretching comprises the steps of: and sequentially carrying out preheating treatment, synchronous stretching treatment and heat setting treatment on the membrane obtained by the cast sheet treatment.
In some more specific embodiments, the pre-heating treatment is carried out in two stages, the temperatures of the two stages being sequentially increased, the temperatures of the two stages being sequentially 130 ℃ to 145 ℃ and 145 ℃ to 155 ℃.
In some more specific embodiments, the simultaneous stretching is performed in three stages, the temperatures of the three stages are sequentially increased, the temperatures of the three stages are sequentially 152 ℃ to 156 ℃,156 ℃ to 160 ℃,160 ℃ to 163 ℃, the longitudinal stretching ratio is 6 times to 8 times, and the transverse stretching ratio is 5 times to 7 times.
In some more specific embodiments, the heat-setting treatment is carried out in two stages, the temperatures of the two stages being sequentially increased, and the temperatures of the two stages being sequentially 162 ℃ to 165 ℃ and 165 ℃ to 169 ℃.
In some embodiments, the biaxial stretching process comprises the steps of: and sequentially carrying out longitudinal stretching treatment, transverse stretching treatment and heat treatment on the membrane obtained by the casting sheet treatment.
In some more specific embodiments, the preheating temperature of the longitudinal stretching treatment is 110 ℃ to 140 ℃, the temperature of the longitudinal stretching is 140 ℃ to 150 ℃, and the longitudinal stretching ratio is 6 times to 8 times.
In some more specific embodiments, the preheat temperature for the transverse stretching process is 120 ℃ to 140 ℃, the temperature for the transverse stretching is 150 ℃ to 160 ℃, the transverse stretching ratio is 5 times to 7 times, and the heat setting temperature is 165 ℃ to 170 ℃.
In some more specific embodiments, the temperature of the heat treatment is from 120 ℃ to 140 ℃.
A third aspect of the present application provides a composite current collector comprising a substrate and a metal layer on at least one surface of the substrate, the substrate comprising the polypropylene film according to the first aspect of the present application or the polypropylene film produced by the production method according to the second aspect of the present application.
In some embodiments, the metal layer has a thickness of 500nm to 2000nm.
In some embodiments, the composite current collector further comprises a protective layer on a surface of the metal layer.
In some more specific embodiments, the material of the protective layer comprises one or more of copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, copper chromium oxide, nickel chromium alloy, graphite, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.
In some more specific embodiments, the protective layer has a thickness of 10nm to 150nm, and the protective layer has a thickness less than or equal to one tenth of the thickness of the metal layer.
A fourth aspect of the present application provides an electrode sheet comprising the composite current collector of the third aspect of the present application.
A fifth aspect of the present application provides a battery comprising an electrode sheet according to the fourth aspect of the present application.
A sixth aspect of the present application provides an electric device comprising the battery according to the fifth aspect of the present application.
Compared with the prior art, the polypropylene film, the preparation method, the composite current collector and the application thereof have at least the following advantages:
(1) The hydroxyl-containing sub-nanowires in the polypropylene film have similarity with polypropylene macromolecules in size and property, the hydroxyl-containing sub-nanowires can be uniformly distributed in a polypropylene macromolecule chain, and a three-dimensional network structure of the hydroxyl-containing sub-nanowires-polypropylene macromolecules can be formed by means of strong intermolecular force between the hydroxyl-containing sub-nanowires and the polypropylene macromolecules, so that the mechanical properties of the prepared polypropylene film and the mechanical properties of the composite current collector can be improved.
(2) The hydroxyl-containing sub-nanowires in the polypropylene film can be uniformly dispersed on the film surface, and the polarity of the polypropylene film surface can be improved due to the fact that the hydroxyl-containing sub-nanowires are rich in polar functional group hydroxyl, so that the surface tension of the polypropylene film can be improved, the improvement of the surface adhesion performance of the polypropylene film can be promoted, and the adhesion force between the polypropylene film and the metal layer can be further improved.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, specific embodiments thereof are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.
In the description of the present application, unless otherwise defined, terms of art and terminology not specifically described have the same meaning as commonly understood by those skilled in the art and are common general knowledge of those skilled in the art, and methods not specifically described are conventional methods well known to those skilled in the art. The term "plurality" in this application means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present application, the technical features described in the open manner include a closed technical solution including the listed features, and also include an open technical solution including the listed features.
One embodiment of the present application provides a polypropylene film, which comprises the following raw materials by mass: 90 to 99.9 percent of polypropylene and 0.1 to 10 percent of hydroxyl-containing sub-nanowire;
the hydroxyl-containing sub-nanowire comprises one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire and a copper oxyhydroxide sub-nanowire.
On one hand, the method can realize the uniform distribution of the hydroxyl-containing nanowires in the polypropylene polymer chain by utilizing the similarity of the hydroxyl-containing nanowires and the polypropylene polymer in size and property, and form a three-dimensional network structure of the hydroxyl-containing nanowires-polypropylene polymer by means of strong intermolecular force between the hydroxyl-containing nanowires and the polypropylene polymer, so as to improve the mechanical property of the polypropylene film; on the other hand, the hydroxyl-containing sub-nanowires which are uniformly dispersed on the polypropylene film surface can improve the polarity of the polypropylene film surface due to the fact that the hydroxyl-containing sub-nanowires are rich in polar functional group hydroxyl, so that the surface tension of the polypropylene film is improved, and the improvement of the surface adhesion performance of the polypropylene film is promoted. This application can control the elasticity modulus, tensile strength, surface tension and defective rate performance such as polypropylene membrane through the content of polypropylene and the sub-nano line that contains the hydroxyl in the control polypropylene membrane to promote the mechanical properties of this polypropylene membrane and the compound mass flow body of metal level and contain this polypropylene membrane. When the content of the hydroxyl-containing sub-nanowires in the polypropylene film is too low, the improvement of the performance of the polypropylene film is not obvious; when the content of the hydroxyl-containing sub-nanowires in the polypropylene film is too high, the film forming property is poor, and film breaking is easy to occur in the preparation process of the polypropylene film, so that the reject ratio is improved.
The hydroxyl group-containing sub-nanowire may include one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire, and a copper oxyhydroxide sub-nanowire, and may further include other kinds of hydroxyl group-containing inorganic oxide sub-nanowires, and the present application is not particularly limited. The hydroxyapatite sub-nanowire, the hydroxyl gadolinium oxide sub-nanowire, the hydroxyl tungsten oxide sub-nanowire and the hydroxyl copper oxide sub-nanowire belong to inorganic oxide sub-nanowires, have good affinity and compatibility with metal atoms, and can promote the adhesion of the surface of the polypropylene film to the metal layer, so that the adhesion of the surface of the polypropylene film and the metal layer can be improved; on the other hand, the synthesis of hydroxy group-containing sub-nanowires is not easy, but the synthesis methods of the above-mentioned hydroxyapatite, gadolinium oxyhydroxide, tungsten oxyhydroxide, and copper oxyhydroxide sub-nanowires are relatively simple and easy to obtain.
In some embodiments, the hydroxyl-containing nanowires have a diameter of less than 1nm and an aspect ratio of greater than or equal to 10.
The diameter and the length-diameter ratio of the hydroxyl-containing sub-nanowire are controlled, the hydroxyl-containing sub-nanowire is further similar to a polypropylene polymer in size and property, so that the hydroxyl-containing sub-nanowire is uniformly distributed in a polymer chain, and a three-dimensional network structure of the hydroxyl-containing sub-nanowire-polypropylene polymer is formed by means of strong intermolecular force between the hydroxyl-containing sub-nanowire and the polypropylene polymer, so that the mechanical property of a polypropylene film is further improved, and the mechanical property of a composite current collector containing the polypropylene film is further improved. When the length-diameter ratio of the hydroxyl-containing sub-nanowire is too low, the hydroxyl-containing sub-nanowire and a polypropylene polymer hardly form an effective three-dimensional network structure, so that the improvement of the mechanical property of the polypropylene film is limited. This application can control the elastic modulus, tensile strength, surface tension and the defective rate of polypropylene film through the slenderness ratio of the sub-nanometer line that control contains hydroxyl to further improve the surface adhesion performance and the mechanical properties of polypropylene film, and then promote the adhesion of this polypropylene film and metal level and contain the mechanical properties of the compound mass flow body of this polypropylene film. It is understood that the diameter of the hydroxyl group-containing nanowires may be, for example, 0.1nm, 0.2nm, 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 0.99nm, etc., and the aspect ratio of the hydroxyl group-containing nanowires may be, for example, 10, 50, 100, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, etc.
In some embodiments, the hydroxyl-containing sub-nanowires have a diameter of less than 1nm, and the hydroxyl-containing sub-nanowires have an aspect ratio of 10 to 1000.
In some embodiments, the polypropylene has a melt index of 3g/10min to 4g/10min at 230 ℃ under a 2.16kg load.
This application can control the elastic modulus, tensile strength, surface tension and the defective rate of polypropylene film through the melt index of control polypropylene to further improve the surface adhesion performance and the mechanical properties of polypropylene film, and then promote the adhesion of this polypropylene film and metal level and contain the mechanical properties of the compound mass flow body of this polypropylene film. When the melt index of the polypropylene is too low, the molecular weight of the polypropylene is too high, so that the film forming property in the film drawing process is poor; when the melt index of polypropylene is too high, the molecular weight of polypropylene is too low, resulting in poor film forming properties, and thus poor mechanical properties of polypropylene films. It is understood that the melt index of polypropylene at 230 ℃ under a 2.16kg load can include, but is not limited to, 3g/10min, 3.1g/10min, 3.2g/10min, 3.3g/10min, 3.4g/10min, 3.5g/10min, 3.6g/10min, 3.7g/10min, 3.8g/10min, 3.9g/10min, or 4g/10min, and the like.
In some embodiments, the polypropylene has a molecular weight distribution index of 4.5 to 5.3.
This application can control the elastic modulus, tensile strength, surface tension and the defective rate of polypropylene film through the molecular weight distribution index of control polypropylene to further improve the surface adhesion performance and the mechanical properties of polypropylene film, and then promote the adhesion of this polypropylene film and metal level and contain the mechanical properties of the compound mass flow body of this polypropylene film. When the molecular weight distribution index of the polypropylene is too high, the content of the small molecular polypropylene is high, so that the mechanical property and the film forming property of a polypropylene film are poor; when the molecular weight distribution index of polypropylene is too low, film forming property in the film drawing process is deteriorated, resulting in a decrease in yield of polypropylene films. It is understood that the molecular weight distribution index of the polypropylene can include, but is not limited to, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, or 5.3, and the like.
In some embodiments, the polypropylene has an isotacticity greater than or equal to 96%.
This application can control the elastic modulus, tensile strength, surface tension and the defective rate of polypropylene film through the isotacticity of control polypropylene to further improve the mechanical properties of polypropylene film, and then promote the mechanical properties who contains the compound mass flow body of this polypropylene film. When the isotacticity of the polypropylene is higher, the higher the regularity of polypropylene molecules is, the higher the orientation degree and the crystallinity of the polypropylene film can be improved, and therefore the mechanical property of the polypropylene film is further improved. It is understood that the isotacticity of the polypropylene may include, but is not limited to, 96%, 97%, 98%, or 99%, etc.
Another embodiment of the present application provides a method for preparing the polypropylene film, comprising the steps of:
mixing polypropylene and hydroxyl-containing sub-nanowires, melting, and extruding molten materials;
the molten material is subjected to a sheet casting treatment and a biaxial stretching treatment in this order.
The polypropylene film prepared by the preparation method comprises the hydroxy-containing sub-nanowire, wherein the hydroxy-containing sub-nanowire comprises one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire and a copper oxyhydroxide sub-nanowire. On one hand, the method can utilize the similarity of the hydroxyl-containing sub-nanowires and the polypropylene polymer in size and property to realize the uniform distribution of the hydroxyl-containing sub-nanowires in the polypropylene polymer chain, and forms a three-dimensional network structure of the hydroxyl-containing sub-nanowires-polypropylene polymer by means of strong intermolecular force between the hydroxyl-containing sub-nanowires and the polypropylene polymer, so that the mechanical property of the prepared polypropylene film is improved; on the other hand, the hydroxyl-containing sub-nanowires which are uniformly dispersed on the polypropylene film surface can improve the polarity of the polypropylene film surface due to the fact that the hydroxyl-containing sub-nanowires are rich in polar functional group hydroxyl, so that the surface tension of the polypropylene film is improved, and the improvement of the surface adhesion performance of the polypropylene film is promoted. According to the preparation method, the content of the polypropylene and the hydroxyl-containing sub-nanowires in the raw material of the polypropylene film is controlled, so that the performances of the polypropylene film, such as the elastic modulus, the tensile strength, the surface tension, the reject ratio and the like, can be controlled, and the adhesive force between the polypropylene film and the metal layer and the mechanical property of the composite current collector containing the polypropylene film are further improved.
In some embodiments, the polypropylene film obtained by the biaxial stretching treatment is further subjected to a winding treatment, and the tension of the winding treatment is 20N/m to 30N/m. It is understood that the take-up tension may be, for example, 20N/m, 22N/m, 24N/m, 26N/m, 28N/m, or 30N/m, etc.
In some embodiments, the temperature of the melting is from 200 ℃ to 260 ℃. It is understood that the melting temperature may include, but is not limited to, 200 deg.C, 210 deg.C, 220 deg.C, 230 deg.C, 240 deg.C, 250 deg.C, 260 deg.C, etc.
In some embodiments, the biaxial stretching comprises the steps of: and sequentially carrying out preheating treatment, synchronous stretching treatment and heat setting treatment on the membrane obtained by the cast sheet treatment. It should be noted that the mechanical properties of the polypropylene film can be improved by controlling the steps and processes of biaxial stretching.
In some more specific embodiments, the pre-heating treatment is carried out in two stages, the temperatures of the two stages being sequentially increased, the temperatures of the two stages being sequentially 130 ℃ to 145 ℃ and 145 ℃ to 155 ℃. It is understood that 130 ℃ to 145 ℃ may include, but is not limited to, 130 ℃, 132 ℃, 135 ℃, 138 ℃, 140 ℃, 142 ℃, or 145 ℃, etc., and 145 ℃ to 155 ℃ may include, but is not limited to, 145 ℃, 147 ℃, 149 ℃, 151 ℃, 153 ℃, or 155 ℃, etc. The temperature of the two pretreatment stages may be, for example, 130 ℃, 140 ℃, 142 ℃,145 ℃, 155 ℃ or the like in this order.
In some more specific embodiments, the simultaneous stretching is carried out in three stages, the temperatures of the three stages being sequentially increased, the temperatures of the three stages being sequentially 152 ℃ to 156 ℃,156 ℃ to 160 ℃,160 ℃ to 163 ℃, the longitudinal stretching ratio being 6 times to 8 times, and the transverse stretching ratio being 5 times to 7 times. It is understood that 152 ℃ to 156 ℃ may include, but is not limited to 152 ℃, 153 ℃, 154 ℃, 155 ℃ or 156 ℃, etc., 156 ℃ to 160 ℃ may include, but is not limited to 156 ℃, 157 ℃, 158 ℃, 159 ℃ or 160 ℃, etc., 160 ℃ to 163 ℃ may include, but is not limited to 160 ℃, 161 ℃,162 ℃, or 163 ℃, etc. The longitudinal stretching ratio may be, for example, 6 times, 6.5 times, 7 times, 7.5 times, or 8 times, and the transverse stretching ratio may be, for example, 5 times, 5.5 times, 6 times, 6.5 times, or 7 times. The temperature of the three stages of simultaneous stretching may be, for example, 152 ℃,156 ℃,160 ℃,156 ℃, 157 ℃, 163 ℃, 155 ℃,156 ℃,160 ℃ or the like in this order.
In some more specific embodiments, the heat-setting treatment is carried out in two stages, the temperatures of the two stages being successively increased, and the temperatures of the two stages being successively 162 ℃ to 165 ℃ and 165 ℃ to 169 ℃. It is understood that 162 ℃ to 165 ℃ may include, but is not limited to, 162 ℃, 163 ℃, 164 ℃ or 165 ℃ and the like, and 165 ℃ to 169 ℃ may include, but is not limited to, 165 ℃, 166 ℃, 167 ℃, 168 ℃ or 169 ℃ and the like. The temperatures of the two stages of the heat-setting treatment may be, for example, 162 ℃ and 165 ℃ or 163 ℃ and 165 ℃ or 165 ℃ and 167 ℃ or 165 ℃ and 169 ℃ in this order.
In some embodiments, the biaxial stretching process comprises the steps of: and sequentially carrying out longitudinal stretching treatment, transverse stretching treatment and heat treatment on the membrane obtained by the casting sheet treatment. It should be noted that the mechanical properties of the polypropylene film can be improved by controlling the steps and processes of biaxial stretching. And (3) cooling the film to room temperature after longitudinal stretching treatment, and then performing transverse stretching treatment.
In some more specific embodiments, the preheat temperature for the longitudinal stretching process is 110 ℃ to 140 ℃, the temperature for the longitudinal stretching is 140 ℃ to 150 ℃, and the longitudinal stretching ratio is 6 times to 8 times. It is understood that the preheating temperature of the longitudinal stretching treatment may be, for example, 110 ℃, 120 ℃,130 ℃ or 140 ℃, the temperature of the longitudinal stretching may be, for example, 140 ℃, 142 ℃, 146 ℃, 148 ℃ or 150 ℃, and the longitudinal stretching ratio may be, for example, 6 times, 6.5 times, 7 times, 7.5 times or 8 times.
In some more specific embodiments, the preheat temperature for the transverse stretching process is 120 ℃ to 140 ℃, the temperature for the transverse stretching is 150 ℃ to 160 ℃, the transverse stretching ratio is 5 times to 7 times, and the heat setting temperature is 165 ℃ to 170 ℃. It is understood that the preheating temperature in the transverse stretching treatment may be, for example, 120 ℃, 125 ℃,130 ℃, 135 ℃ or 140 ℃, the transverse stretching temperature may be, for example, 150 ℃,152 ℃, 154 ℃,156 ℃, 158 ℃ or 160 ℃, and the transverse stretching ratio may be, for example, 5 times, 5.5 times, 6 times, 6.5 times or 7 times.
In some more specific embodiments, the temperature of the heat treatment is from 120 ℃ to 140 ℃. The heat treatment is performed to eliminate internal stress in the film and to improve thermal stability of the film. It is understood that the temperature of the heat treatment may be, for example, 120 ℃, 125 ℃,130 ℃, 135 ℃ or 140 ℃.
In another embodiment, the present disclosure provides a composite current collector, including a substrate and a metal layer, the metal layer being located on at least one surface of the substrate, and the substrate includes the polypropylene film or the polypropylene film prepared by the preparation method.
The surface adhesion performance and the mechanical property of the polypropylene film or the polypropylene film prepared by the preparation method are improved, so that the adhesive force between the base material and the metal layer in the composite current collector and the mechanical property of the composite current collector are improved. The metal layer is provided on the surface of the substrate for the purpose of electrical conduction.
In some embodiments, the material of the metal layer includes one or more of copper, aluminum, silver, gold, nickel, and alloys thereof.
In some embodiments, the metal layer has a thickness of 500nm to 2000nm. It is understood that the thickness of the metal layer may be, for example, 500nm, 800nm, 1100nm, 1400nm, 1700nm, 2000nm, or the like. In some preferred embodiments, the metal layer has a thickness of 700nm to 1200nm.
In some embodiments, the method of preparing the metal layer comprises one or more of physical vapor deposition, electroplating, and electroless plating.
In some more specific embodiments, the physical vapor deposition comprises one or more of resistance-heated vacuum evaporation, electron beam-heated vacuum evaporation, laser-heated vacuum evaporation, and magnetron sputtering.
In some embodiments, the composite current collector further comprises a protective layer on a surface of the metal layer. The protective layer can prevent the metal layer from being chemically corroded or physically damaged.
In some more specific embodiments, the material of the protective layer includes one or more of copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, copper chromium oxide, nickel chromium alloy, graphite, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.
In some more specific embodiments, the protective layer has a thickness of 10nm to 150nm, and the protective layer has a thickness less than or equal to one tenth of the thickness of the metal layer. It is understood that the thickness of the protective layer may include, but is not limited to, 10nm, 20nm, 30nm, 50nm, 70nm, 100nm, 120nm, 150nm, or the like. In some preferred embodiments, the protective layer has a thickness of 20nm to 100nm, and the protective layer has a thickness less than or equal to one tenth of the thickness of the metal layer.
In some more specific embodiments, the method of preparing the protective layer comprises one or more of physical vapor deposition, chemical vapor deposition, in-situ formation, and coating. The physical vapor deposition is preferably one or more of vacuum evaporation and magnetron sputtering. The chemical vapor deposition is preferably one or more of atmospheric pressure chemical vapor deposition and plasma enhanced chemical vapor deposition. The in-situ forming is preferably a method for forming a metal oxide passivation layer on the surface of the metal layer in situ. The coating is preferably one or more of die coating, blade coating and extrusion coating.
Yet another embodiment of this application still provides an electrode piece, includes above-mentioned compound mass flow body. It should be noted that, for example, the electrode sheet of the present application may be obtained by mixing a positive electrode active material/a negative electrode active material, a conductive agent, a binder and a solvent to form a slurry, and coating the slurry on the composite current collector of the present application by using a method for preparing an electrode sheet, which is well known to those skilled in the art. The electrode sheet can be divided into a positive electrode sheet and a negative electrode sheet according to the difference of active materials. The method for preparing the electrode plate is not particularly limited, and the above preparation method may be a preparation method known to those skilled in the art.
Still another embodiment of this application provides a battery, includes above-mentioned electrode sheet. The electrode sheet may be a positive electrode sheet or a negative electrode sheet, and the battery is not particularly limited in this application, and the battery may include, but is not limited to, a lithium ion secondary battery, a lithium ion polymer secondary battery, a lithium metal secondary battery, a lithium polymer secondary battery, or the like.
Still another embodiment of this application still provides a power consumption device, includes above-mentioned battery. The battery may be used as a power source or an energy storage unit in the electrical device, and the electrical device includes, but is not limited to, an electric vehicle, a smart home appliance, a computer, a tablet, a mobile phone, a digital camera, and the like.
The present application will be described in further detail with reference to specific examples and comparative examples.
Example 1
The preparation method of the polypropylene film comprises the following steps:
s1, selecting raw materials
The selected polypropylene has a melt index of 3g/10min, a molecular weight distribution index of 4.5 and an isotacticity of 96% at 230 ℃ and under a load of 2.16 kg; the selected hydroxyl-containing sub-nanowire is a hydroxyapatite sub-nanowire with the diameter of 0.8nm and the length-diameter ratio of 10;
s2. Melt extrusion
Respectively adding the raw materials into corresponding double-screw extruders, respectively melting 99.9% and 0.1% of polypropylene and hydroxyapatite nanowires by mass percent at 240 ℃, filtering by a filter (10-micron filter screen), and extruding a melt through a die head at the temperature of 250 ℃;
s3. Casting sheet
Casting the molten material extruded by the die head onto a casting sheet roller, and performing cooling treatment and molding by the casting sheet roller and water cooling, wherein the cooling temperature is 25 ℃;
s4, bidirectional stretching
And (4) asynchronously stretching the membrane obtained in the step (S3):
first, longitudinal stretching is performed: preheating at 135 deg.C, stretching at 140 deg.C, longitudinal stretching ratio of 7 times, and cooling to room temperature after longitudinal stretching; then, transverse stretching is carried out: preheating at 135 deg.C, stretching at 150 deg.C, stretching ratio at 6 times, and heat setting at 165 deg.C; then, carrying out heat treatment at the temperature of 125 ℃;
s5, rolling
And (4) cooling the film obtained in the step (S4) by platform area air, and then, entering a winding system for winding the film sheet by a traction system, wherein the winding tension is 30N/m.
The preparation method of the composite current collector comprises the following steps:
s1, placing the prepared polypropylene film in a magnetron sputtering chamber, plating a metal layer with the thickness of 80nm on the polypropylene film in the magnetron sputtering chamber by a magnetron sputtering method by taking copper metal with the purity of 99.99% as a target material and argon as an air source to obtain a composite film;
s2, electroplating by taking the composite film prepared in the step S1 as a base material, wherein the electroplating comprises the following three processes:
(1) Preparing a metal layer by electroplating: the components of the electroplating solution are 150g/L copper sulfate, 120g/L sulfuric acid, 60mg/L chloride ion, 1mg/L sodium polydithio-dipropyl sulfonate, 0.5mg/L jiannan green and 200mg/L polyethylene glycol 8000, the temperature of the electroplating solution is 25 ℃, and the average cathode current density is 2A/dm 2 Electroplating for 5min;
(2) Preparing a protective layer: after the electroplating is finished, cleaning the plated composite film in a clear water tank, preparing a surface protection layer in a protection layer preparation tank containing 5g/L of potassium dichromate water solution, treating at 25 ℃ for 30s, and finally cleaning through the clear water tank;
(3) And (3) drying: and drying the cleaned composite film at the temperature of 70 ℃ in an oven to obtain the composite copper current collector with the total thickness of the copper metal layer and the protective layer being 1 mu m.
Example 2
The polypropylene film was prepared essentially as in example 1, except that: the mass percentage of the polypropylene and the hydroxyapatite nanowire in the raw materials is respectively 95 percent and 5 percent.
The composite current collector was prepared in the same manner as in example 1.
Example 3
The polypropylene film was prepared essentially as in example 1, except that: the mass percentage of the polypropylene and the hydroxyapatite nanowire in the raw materials is respectively 90 percent and 10 percent.
The composite current collector was prepared in the same manner as in example 1.
Example 4
The polypropylene film was prepared in substantially the same manner as in example 1, except that: the length-diameter ratio of the hydroxyapatite sub-nanowire in the raw material is 100.
The composite current collector was prepared in the same manner as in example 1.
Example 5
The polypropylene film was prepared essentially as in example 1, except that: the length-diameter ratio of the hydroxyapatite sub-nanowire in the raw material is 1000.
The method of making the composite current collector was the same as in example 1.
Example 6
The polypropylene film was prepared essentially as in example 1, except that: the melt index of the polypropylene in the feed was 3.5g/10min at 230 ℃ under a 2.16kg load.
The method of making the composite current collector was the same as in example 1.
Example 7
The polypropylene film was prepared essentially as in example 1, except that: the melt index of the polypropylene in the raw material at 230 ℃ under a load of 2.16kg was 4g/10min.
The composite current collector was prepared in the same manner as in example 1.
Example 8
The polypropylene film was prepared in substantially the same manner as in example 1, except that: the polypropylene in the feed had a molecular weight distribution index of 4.9.
The method of making the composite current collector was the same as in example 1.
Example 9
The polypropylene film was prepared essentially as in example 1, except that: the molecular weight distribution index of the polypropylene in the feed was 5.3.
The method of making the composite current collector was the same as in example 1.
Example 10
The polypropylene film was prepared in substantially the same manner as in example 1, except that: the isotacticity of the polypropylene in the raw material was 97%.
The method of making the composite current collector was the same as in example 1.
Example 11
The polypropylene film was prepared essentially as in example 1, except that: the isotacticity of the polypropylene in the raw material was 99%.
The method of making the composite current collector was the same as in example 1.
Example 12
The polypropylene film was prepared essentially as in example 1, except that: the step S4 of bidirectional stretching adopts a synchronous stretching process, and the stretching process is as follows: the method comprises the following steps of dividing the device into a preheating area, a stretching area and a heat setting area, wherein the preheating area is divided into two sections, and the temperature is sequentially increased, namely 135 ℃ and 150 ℃; the stretching area is divided into three sections, and the temperature is sequentially increased, namely 154 ℃, 157 ℃ and 160 ℃; stretching ratio: the longitudinal stretching magnification was 7 and the transverse stretching magnification was 6. The heat setting zone is divided into two sections, and the temperature is increased sequentially, namely 163 ℃ and 166 ℃.
The composite current collector was prepared in the same manner as in example 1.
Example 13
The polypropylene film was prepared essentially as in example 1, except that: replacing the hydroxyapatite sub-nanowire in the raw material with a gadolinium oxyhydroxide sub-nanowire.
The method of making the composite current collector was the same as in example 1.
Example 14
The polypropylene film was prepared essentially as in example 1, except that: the hydroxyapatite sub-nanowire in the raw material is a tungsten oxyhydroxide sub-nanowire.
The method of making the composite current collector was the same as in example 1.
Example 15
The polypropylene film was prepared in substantially the same manner as in example 1, except that: replacing the hydroxyapatite sub-nanowire in the raw material with the copper oxyhydroxide sub-nanowire.
The composite current collector was prepared in the same manner as in example 1.
Example 16
The polypropylene film was prepared in substantially the same manner as in example 1, except that: the length-diameter ratio of the hydroxyapatite sub-nanowire in the raw material is 9.
The method of making the composite current collector was the same as in example 1.
Example 17
The polypropylene film was prepared essentially as in example 1, except that: the melt index of the polypropylene in the feed at 230 ℃ under a load of 2.16kg was 2.9g/10min.
The method of making the composite current collector was the same as in example 1.
Example 18
The polypropylene film was prepared essentially as in example 1, except that: the melt index of the polypropylene in the feed at 230 ℃ under a load of 2.16kg was 4.1g/10min.
The composite current collector was prepared in the same manner as in example 1.
Example 19
The polypropylene film was prepared essentially as in example 1, except that: the molecular weight distribution index of the polypropylene in the feed was 4.4.
The composite current collector was prepared in the same manner as in example 1.
Example 20
The polypropylene film was prepared essentially as in example 1, except that: the molecular weight distribution index of the polypropylene in the feed was 5.4.
The method of making the composite current collector was the same as in example 1.
Example 21
The polypropylene film was prepared essentially as in example 1, except that: the isotacticity of the polypropylene in the raw material was 95%.
The method of making the composite current collector was the same as in example 1.
Comparative example 1
The polypropylene film was prepared essentially as in example 1, except that: the raw material does not contain hydroxyapatite nanowires, and the mass percentage of the polypropylene is 100%.
The method of making the composite current collector was the same as in example 1.
Comparative example 2
The polypropylene film was prepared essentially as in example 1, except that: the mass contents of the polypropylene and the hydroxyapatite nanowire in the raw materials are respectively 89% and 11%.
The method of making the composite current collector was the same as in example 1.
Performance testing of Polypropylene films and composite Current collectors
The purpose of preparing the polypropylene film is to improve the mechanical property and the surface adhesion property of the film, and further improve the performance of a composite current collector prepared by using the polypropylene film as a base material. For a polypropylene film, the mechanical properties of the film are usually represented by the elastic modulus and tensile strength of the film, and the surface adhesion property of the polypropylene film mainly depends on the surface tension of the polypropylene film and is finally expressed on the adhesive force between the polypropylene film and a metal layer in the composite current collector. In addition, the reject ratio caused by membrane rupture in the preparation process of the polypropylene membrane is counted. The results are shown in tables 1 and 2.
(1) The test method of the elastic modulus and the tensile strength comprises the following steps: and testing the elastic modulus and tensile strength of the prepared polypropylene film and the composite current collector according to the national standard GB/T1040.3-2006.
(2) Surface tension test method: the surface tension of the prepared polypropylene film was tested according to GB/T14216-2008.
(3) The method for testing the adhesive force between the polypropylene film and the metal layer in the composite current collector comprises the following steps: at 1mm thicknessAdhering a Permacel P-94 double-sided adhesive tape on the aluminum foil, adhering a composite current collector on the double-sided adhesive tape, covering a layer of ethylene acrylic acid copolymer film (Dupont Nurcel0903, thickness 50 μm) on the composite current collector, and covering the film on the aluminum foil at 1.3 × 10 5 N/m 2 Hot pressing at 120 deg.C for 10s, cooling to room temperature, and cutting into small strips of 150mm × 15 mm. And then fixing the small strip of the ethylene acrylic acid copolymer film of the sample on an upper clamp of a tensile machine, fixing the rest part on a lower clamp, peeling the small strip of the ethylene acrylic acid copolymer film and the fixed strip of the ethylene acrylic acid copolymer film at an angle of 180 degrees and a speed of 100mm/min, and testing the peeling force, namely the adhesive force between the polypropylene film and the metal layer.
(4) The method for testing the defective rate comprises the following steps: the number of defective products caused by film rupture in the preparation process is proportional to the total product number, and the number is calculated by the length because the widths are consistent.
TABLE 1 Performance test results for Polypropylene films
| Group of | Modulus of elasticity (MPa) | Tensile Strength (MPa) | Surface tension (mN/m) | Percent defective |
| Example 1 | 4010 | 200 | 37 | 0 |
| Example 2 | 5266 | 273 | 46 | 0 |
| Example 3 | 4311 | 218 | 51 | 0 |
| Example 4 | 4451 | 226 | 40 | 0 |
| Example 5 | 4845 | 249 | 44 | 0 |
| Example 6 | 3853 | 191 | 38 | 0 |
| Example 7 | 3672 | 180 | 40 | 0 |
| Example 8 | 3893 | 193 | 38 | 0 |
| Example 9 | 3755 | 185 | 39 | 0 |
| Example 10 | 4195 | 211 | 37 | 0 |
| Example 11 | 4522 | 230 | 37 | 0 |
| Example 12 | 4113 | 206 | 37 | 0 |
| Example 13 | 4079 | 204 | 39 | 0 |
| Example 14 | 3923 | 195 | 38 | 0 |
| Example 15 | 3977 | 198 | 40 | 0 |
| Example 16 | 3585 | 175 | 35 | 0 |
| Example 17 | 4213 | 212 | 34 | 6 |
| Example 18 | 3539 | 172 | 42 | 3 |
| Example 19 | 4096 | 205 | 35 | 5 |
| Example 20 | 3568 | 174 | 40 | 2 |
| Examples21 | 3619 | 177 | 37 | 0 |
| Comparative example 1 | 3503 | 170 | 30 | 0 |
| Comparative example 2 | 3839 | 191 | 52 | 3 |
Table 2 performance test results of composite current collectors
From examples 1 to 3 and comparative examples 1 to 2, it can be seen that: the content of the hydroxyapatite nanowires in the raw materials is increased, the elastic modulus and the tensile strength of the prepared polypropylene film show a trend of increasing first and then decreasing, and the elastic modulus and the tensile strength of the corresponding composite current collector also show the same trend; the surface tension of the polypropylene film tends to increase, and the adhesive force between the polypropylene film and the metal layer in the corresponding composite current collector tends to increase. When the content of the hydroxyapatite nanowires in the raw materials is too high, membrane rupture is easy to occur in the preparation process of the polypropylene membrane. From examples 1 to 15 and comparative example 1, it can be seen that: compared with the polypropylene film prepared in the comparative example 1, the polypropylene films prepared in the examples 1 to 15 of the present application have obviously improved mechanical properties and surface adhesion properties.
As can be seen from examples 1, 4, 5 and 16: the length-diameter ratio of the hydroxyapatite sub-nanowires in the raw materials is improved, the elastic modulus and the tensile strength of the prepared polypropylene film show an increasing trend, and the elastic modulus and the tensile strength of the corresponding composite current collector also show the same trend; the surface tension of the polypropylene film tends to increase, and the adhesive force between the polypropylene film and the metal layer in the corresponding composite current collector tends to increase. When the length-diameter ratio of the hydroxyapatite sub-nanowire is too low, the performance of the prepared polypropylene film and the composite current collector is not obviously improved.
From example 1, example 6, example 7, example 17 and example 18, it can be seen that: the melt index of polypropylene in the raw materials is improved, the elastic modulus and the tensile strength of the prepared polypropylene film show a reduced trend, and the elastic modulus and the tensile strength of the corresponding composite current collector also show the same trend; the surface tension of the polypropylene film is increased, and the adhesive force between the polypropylene film and the metal layer in the corresponding composite current collector tends to be increased. When the melt index of polypropylene in the raw material is too low or too high, the polypropylene film is easy to break in the preparation process.
From example 1, example 8, example 9, example 19 and example 20, it can be seen that: the molecular weight distribution index of polypropylene in the raw material is improved, the elastic modulus and the tensile strength of the prepared polypropylene film show a reduced trend, and the elastic modulus and the tensile strength of the corresponding composite current collector also show the same trend; the surface tension of the polypropylene film is increased, and the adhesive force between the polypropylene film and the metal layer in the corresponding composite current collector tends to be increased. When the molecular weight distribution index of polypropylene in the raw material is too low or too high, the polypropylene film is easy to break in the preparation process.
From examples 1, 10, 11 and 21, it can be seen that: the isotacticity of polypropylene in the raw materials is improved, the elastic modulus and the tensile strength of the prepared polypropylene film show an increasing trend, and the elastic modulus and the tensile strength of the corresponding composite current collector also show the same trend; and the surface tension of the polypropylene film is unchanged, and the adhesive force between the polypropylene film and the metal layer in the corresponding composite current collector is unchanged.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent application shall be subject to the appended claims, and the description shall be used to interpret the contents of the claims.
Claims (11)
1. The polypropylene film is characterized by comprising the following raw materials in percentage by mass: 90 to 99.9 percent of polypropylene and 0.1 to 10 percent of hydroxyl-containing sub-nanowire;
the hydroxyl-containing sub-nanowire comprises one or more of a hydroxyapatite sub-nanowire, a gadolinium oxyhydroxide sub-nanowire, a tungsten oxyhydroxide sub-nanowire and a copper oxyhydroxide sub-nanowire.
2. The polypropylene film of claim 1, wherein the hydroxyl-containing sub-nanowires have a diameter of less than 1nm, and an aspect ratio of the hydroxyl-containing sub-nanowires is greater than or equal to 10; preferably, the aspect ratio of the hydroxyl-containing sub-nanowire is 10 to 1000.
3. The polypropylene film according to any one of claims 1 to 2, wherein the polypropylene has at least one of the following characteristics (1) to (3):
(1) The melt index of the polypropylene at 230 ℃ under a load of 2.16kg is 3g/10 min-4 g/10min;
(2) The molecular weight distribution index of the polypropylene is 4.5-5.3;
(3) The polypropylene has an isotacticity greater than or equal to 96%.
4. A method for producing a polypropylene film according to any one of claims 1 to 3, comprising the steps of:
mixing the polypropylene and the hydroxyl-containing sub-nanowires, melting, and extruding molten materials;
and sequentially carrying out casting sheet treatment and biaxial tension treatment on the molten material.
5. The method of claim 4, wherein the biaxial stretching comprises the steps of: sequentially carrying out preheating treatment, synchronous stretching treatment and heat setting treatment on the membrane obtained by the casting sheet treatment;
optionally, the temperature of the melting is 200 ℃ to 260 ℃;
optionally, the preheating treatment is performed in two stages, wherein the temperatures of the two stages are sequentially increased, and the temperatures of the two stages are 130-145 ℃ and 145-155 ℃ in sequence;
optionally, the synchronous stretching is performed in three stages, the temperature of the three stages is sequentially increased, the temperature of the three stages is sequentially 152-156 ℃, 156-160 ℃, 160-163 ℃, the longitudinal stretching ratio is 6-8 times, and the transverse stretching ratio is 5-7 times;
optionally, the heat setting treatment is performed in two stages, wherein the temperatures of the two stages are sequentially increased, and the temperatures of the two stages are 162 ℃ to 165 ℃ and 165 ℃ to 169 ℃.
6. The method for preparing according to claim 4, wherein the biaxial stretching treatment comprises the steps of: sequentially carrying out longitudinal stretching treatment, transverse stretching treatment and heat treatment on the membrane obtained by the casting sheet treatment;
optionally, the preheating temperature of the longitudinal stretching treatment is 110-140 ℃, the longitudinal stretching temperature is 140-150 ℃, and the longitudinal stretching ratio is 6-8 times;
optionally, the preheating temperature of the transverse stretching treatment is 120-140 ℃, the transverse stretching temperature is 150-160 ℃, the transverse stretching ratio is 5-7 times, and the heat setting temperature is 165-170 ℃;
optionally, the temperature of the heat treatment is 120 ℃ to 140 ℃.
7. A composite current collector comprising a substrate and a metal layer, wherein the metal layer is located on at least one surface of the substrate, and the substrate comprises the polypropylene film according to any one of claims 1 to 3 or the polypropylene film produced by the production method according to any one of claims 4 to 6;
optionally, the thickness of the metal layer is 500nm to 2000nm.
8. The composite current collector of claim 7, further comprising a protective layer on a surface of the metal layer;
optionally, the material of the protective layer comprises one or more of copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, copper chromium oxide, nichrome, graphite, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene;
optionally, the thickness of the protective layer is 10nm to 150nm, and the thickness of the protective layer is less than or equal to one tenth of the thickness of the metal layer.
9. An electrode sheet comprising the composite current collector of any one of claims 7 to 8.
10. A battery comprising the electrode sheet claimed in claim 9.
11. An electric device comprising the battery according to claim 10.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211656040.2A CN115850863A (en) | 2022-12-22 | 2022-12-22 | Polypropylene film, preparation method thereof, composite current collector and application |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211656040.2A CN115850863A (en) | 2022-12-22 | 2022-12-22 | Polypropylene film, preparation method thereof, composite current collector and application |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117261303A (en) * | 2023-11-21 | 2023-12-22 | 扬州纳力新材料科技有限公司 | Polypropylene film and preparation method thereof, composite current collector, electrode plate and application |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117261303A (en) * | 2023-11-21 | 2023-12-22 | 扬州纳力新材料科技有限公司 | Polypropylene film and preparation method thereof, composite current collector, electrode plate and application |
| CN117261303B (en) * | 2023-11-21 | 2024-02-23 | 扬州纳力新材料科技有限公司 | Polypropylene film and preparation method thereof, composite current collector, electrode plate and application |
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