CN114649637A - Co-jet spinning lithium ion battery diaphragm and preparation method thereof - Google Patents
Co-jet spinning lithium ion battery diaphragm and preparation method thereof Download PDFInfo
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- CN114649637A CN114649637A CN202210286551.3A CN202210286551A CN114649637A CN 114649637 A CN114649637 A CN 114649637A CN 202210286551 A CN202210286551 A CN 202210286551A CN 114649637 A CN114649637 A CN 114649637A
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- 238000009987 spinning Methods 0.000 title claims abstract description 63
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 60
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 60
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 239000012528 membrane Substances 0.000 claims abstract description 67
- 238000001523 electrospinning Methods 0.000 claims abstract description 37
- 229920000642 polymer Polymers 0.000 claims abstract description 29
- 239000000126 substance Substances 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000000835 fiber Substances 0.000 claims abstract description 17
- 239000002131 composite material Substances 0.000 claims abstract description 16
- 239000002904 solvent Substances 0.000 claims abstract description 14
- 239000000243 solution Substances 0.000 claims description 51
- 239000007788 liquid Substances 0.000 claims description 27
- 239000004793 Polystyrene Substances 0.000 claims description 12
- 238000007787 electrohydrodynamic spraying Methods 0.000 claims description 11
- 229920002223 polystyrene Polymers 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 10
- 239000007921 spray Substances 0.000 claims description 9
- -1 polyethylene terephthalate Polymers 0.000 claims description 8
- 239000002994 raw material Substances 0.000 claims description 8
- 239000002033 PVDF binder Substances 0.000 claims description 7
- 229920001577 copolymer Polymers 0.000 claims description 7
- 229920001721 polyimide Polymers 0.000 claims description 7
- 229920000098 polyolefin Polymers 0.000 claims description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 7
- 239000004642 Polyimide Substances 0.000 claims description 6
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 6
- 239000002105 nanoparticle Substances 0.000 claims description 6
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 6
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 6
- 229920006380 polyphenylene oxide Polymers 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- LLLVZDVNHNWSDS-UHFFFAOYSA-N 4-methylidene-3,5-dioxabicyclo[5.2.2]undeca-1(9),7,10-triene-2,6-dione Chemical compound C1(C2=CC=C(C(=O)OC(=C)O1)C=C2)=O LLLVZDVNHNWSDS-UHFFFAOYSA-N 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 10
- 238000007598 dipping method Methods 0.000 abstract description 3
- 230000004048 modification Effects 0.000 abstract description 3
- 238000012986 modification Methods 0.000 abstract description 3
- 229920001223 polyethylene glycol Polymers 0.000 description 16
- WOBHKFSMXKNTIM-UHFFFAOYSA-N Hydroxyethyl methacrylate Chemical compound CC(=C)C(=O)OCCO WOBHKFSMXKNTIM-UHFFFAOYSA-N 0.000 description 14
- 239000002202 Polyethylene glycol Substances 0.000 description 14
- 238000005507 spraying Methods 0.000 description 13
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 12
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 description 7
- 238000001878 scanning electron micrograph Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000010041 electrostatic spinning Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 239000002861 polymer material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- QTMDXZNDVAMKGV-UHFFFAOYSA-L copper(ii) bromide Chemical compound [Cu+2].[Br-].[Br-] QTMDXZNDVAMKGV-UHFFFAOYSA-L 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000005686 electrostatic field Effects 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- DWFKOMDBEKIATP-UHFFFAOYSA-N n'-[2-[2-(dimethylamino)ethyl-methylamino]ethyl]-n,n,n'-trimethylethane-1,2-diamine Chemical compound CN(C)CCN(C)CCN(C)CCN(C)C DWFKOMDBEKIATP-UHFFFAOYSA-N 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- 229910021590 Copper(II) bromide Inorganic materials 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001955 polyphenylene ether Polymers 0.000 description 1
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- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
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- 238000002145 thermally induced phase separation Methods 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
- D04H1/4282—Addition polymers
- D04H1/4318—Fluorine series
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
- D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
- D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/491—Porosity
Abstract
The embodiment of the invention discloses a co-jet spinning lithium ion battery diaphragm and a preparation method thereof. The co-jet spinning lithium ion battery diaphragm comprises an electrospinning film and a modified substance attached to the electrospinning film; the electrospun membrane is of a porous skeleton structure; the modifying substance is attached to the electrospun membrane in an amorphous shape. According to the co-jet spinning lithium ion battery diaphragm and the preparation method thereof, the modified substances are introduced to the surface of the electrospun fiber, so that the compatibility of a single polymer and electrolyte is improved, and the operability and mechanical property of the diaphragm are improved by adhering adjacent fibers of an electrospun membrane; the modified substance is introduced by adopting a co-jet spinning method, so that the problems of membrane size shrinkage, solvent residue, uneven adhesion and the like caused by solvent volatilization of the composite membrane prepared by the traditional membrane dipping method can be solved, and the porous membrane is prepared. Thus, the properties such as wettability, thermal stability, mechanical strength and the like of the single polymer electrospun membrane can be further improved through surface adhesion modification.
Description
Technical Field
The invention relates to a lithium ion battery diaphragm material and a preparation method thereof, and relates to the technical field of the lithium ion battery diaphragm material, in particular to a co-jet spinning lithium ion battery diaphragm and a preparation method thereof.
Background
Lithium Ion Batteries (LIBs) are attracting much attention as novel energy storage power sources due to their characteristics of high specific energy, small volume, long cycle life, light weight, little pollution and the like, and are expected to be widely applied in the fields of electric vehicles, foldable electronic devices, large-scale energy storage devices, smart grids and the like. The diaphragm is one of important components in the lithium ion battery, is an electronic poor conductor, has the main functions of obstructing positive and negative electrodes, preventing contact short circuit and providing a lithium ion transmission channel, and the properties of the diaphragm greatly influence the cycle life, the rate capability, the safety and other properties of the lithium ion battery.
The existing commercial lithium ion battery diaphragm mainly adopts polyolefin (polyethylene and polypropylene) high polymers, the raw material of the diaphragm is prepared by a melt-drawing method, a thermally induced phase separation method, a solvent casting method and other methods, the affinity of the diaphragm material and electrolyte is not good enough, and the time for the electrolyte to soak the diaphragm is prolonged, so that the production cost is increased, and the production efficiency is reduced; the traditional diaphragm also has the defects of smooth surface, small specific surface area, low porosity of the diaphragm, poor thermal shrinkage performance and the like, so that the lithium ion passing rate of a lithium ion battery assembled by the traditional diaphragm is not high enough when the lithium ion battery works, the capacity and the cycle performance of the battery are influenced to a certain extent, and the traditional diaphragm has great potential safety hazard in the using process.
The electrostatic spinning is a high-efficiency and simple method for preparing the high-porosity fiber membrane. The fiber prepared by the electrostatic spinning method has the advantages of high membrane porosity and large specific surface area, and the special interpenetrating network structure characteristic of the fiber enables the electrolyte to be well filled in a membrane matrix. However, the film prepared by the pure electrostatic spinning method is mainly overlapped by Van der Waals force between the fiber yarns, so that the electrospun film has insufficient mechanical property and poor thermal shrinkage property, and is easy to be damaged by lithium branches or external force to cause short circuit of the battery when applied to the lithium battery, thereby causing safety accidents.
Disclosure of Invention
In view of the deficiencies of the prior art, one aspect of the present invention provides a co-jet spinning lithium ion battery separator to solve at least one technical problem in the prior art.
The technical scheme of the co-jet spinning lithium ion battery diaphragm mainly comprises the following steps:
a co-jet spun lithium ion battery separator comprising an electrospun membrane and a modifying substance attached to the electrospun membrane; the electrospun membrane is of a porous skeleton structure; the modifying substance is attached to the electrospun membrane in an amorphous shape.
According to a preferred embodiment of the present invention, the electrospun membrane is one or more of a polyolefin membrane, a polyvinylidene fluoride and copolymer membrane thereof, a polyethylene terephthalate membrane, a polystyrene membrane, a polyphenylene oxide membrane, a polystyrene membrane, and a polyimide membrane.
According to a preferred embodiment of the present invention, the electrospun membrane has a thickness of 10-100 μm.
According to a preferred embodiment of the present invention, the modifying substance is one or more of a branched modified polymer, a hyperbranched modified polymer, and modified organic-inorganic nanoparticles.
The invention also provides a preparation method of the co-jet spinning lithium ion battery diaphragm.
The preparation method of the co-jet spinning lithium ion battery diaphragm comprises the following steps:
preparing an electrospinning solution: adding a high molecular raw material into a first solvent, and mechanically stirring and dissolving to prepare an electrospinning solution;
preparing an electronic injection liquid: dissolving the modified substance in a second solvent, and mechanically stirring to obtain an electric spray liquid;
preparing a co-jet spinning lithium ion battery diaphragm: and (3) preparing the co-jet spinning lithium ion battery diaphragm from the electro-spinning solution and the electro-spraying solution in a coaxial co-jet spinning mode.
According to a preferred embodiment of the invention, the electrospinning solution and the electro-spraying liquid are respectively added into an injector, the electrospinning solution is connected with a core needle, the electro-spraying liquid is connected with a shell nozzle, and an electrospinning device is connected for standby; and adjusting the distance between the coaxial co-jet spinning needle and the receiving roller and the solution flow rate, wrapping the outer wall of the core nozzle by the spinning solution when small liquid drops are formed below the core nozzle, turning on a high-voltage power supply, adjusting the voltage, and preparing the lithium ion composite diaphragm.
According to a preferred embodiment of the present invention, the polymer material is one or more of polyolefin, polyvinylidene fluoride and its copolymer, polyethylene terephthalate, polystyrene, polyphenylene oxide, polystyrene and polyimide.
According to a preferred embodiment of the present invention, the mass fraction of the polymeric raw material in the electrospinning solution is 10% to 20%.
According to a preferred embodiment of the present invention, the modifying substance is one or more of a branched modified polymer, a hyperbranched modified polymer, and modified organic-inorganic nanoparticles.
According to a preferred embodiment of the present invention, the polymer material is a polyvinylidene fluoride-hexafluoropropylene copolymer; the modified substance is three-arm branched polyethylene glycol methacrylate (3 PEG); the first solvent is a mixture of 3: 1, a mixed solution of acetone and N-N dimethylformamide; the second solvent is acetone.
According to a preferred embodiment of the present invention, the method for preparing the co-jet spinning lithium ion battery separator comprises:
preparing an electrospinning solution: will MW＝4×105g mol-1PVDF-HFP (b) was added in a volume ratio of 3: 1, fully stirring in a mixed solution of acetone and N-N dimethylformamide to prepare a polymer solution with the mass fraction of 16%;
preparing an electric spraying liquid: dissolving the three-arm branched polyethylene glycol methacrylate in acetone to prepare a 6 wt% uniform solution, and mechanically stirring to prepare the electric spray liquid;
preparing a co-jet spinning lithium ion battery diaphragm: respectively adding the spinning solution and the electro-spraying liquid into a 5ml injector, adopting a coaxial co-spraying spinning needle, connecting the electro-spinning liquid with a core needle, connecting the electro-spraying liquid with a shell needle, and pumping the electro-spraying liquid with an injector for 1.2ml h-1The injection rate of (1) propels the solution, the DC high voltage generator is used as a device of the high voltage electrostatic field, the set voltage is 18kV, the cylindrical roller is used as a receiving plate, the rotating speed of the roller is 500r ≤-1The vertical distance from the roller to the core needle is 15cm, and the core needle is lower than the shell needle by a certain length so as to ensure that the electrospinning filament is wrapped with the three-arm branched polyethylene glycol methacrylate polymer; when small liquid drops are formed below the core nozzle, the spinning solution wraps the outer wall of the core nozzle, a high-voltage power supply is turned on, the voltage is adjusted, and the lithium ion composite diaphragm is prepared; and after spinning is finished, placing the composite diaphragm in a vacuum drying oven for drying for 24 hours at 40 ℃ to obtain the lithium ion battery diaphragm.
Compared with the prior art, the co-jet spinning lithium ion battery diaphragm and the preparation method thereof have the following beneficial effects:
according to the co-jet spinning lithium ion battery diaphragm and the preparation method thereof, the modified substances are introduced to the surface of the electrospun fiber, so that the compatibility of a single polymer and electrolyte is improved, and the operability and mechanical property of the diaphragm are improved by adhering adjacent fibers of an electrospun membrane; the modified substance is introduced by adopting a co-jet spinning method, so that the problems of membrane size shrinkage, solvent residue, uneven adhesion and the like caused by solvent volatilization of the composite membrane prepared by the traditional membrane dipping method can be solved, and the porous membrane is prepared. Thus, the properties such as wettability, thermal stability, mechanical strength and the like of the single polymer electrospun membrane can be further improved through surface adhesion modification.
Additional features of the invention will be set forth in part in the description which follows. Additional features of some aspects of the invention will become apparent to those of ordinary skill in the art upon examination of the following description and accompanying drawings or may be learned by the manufacture or operation of the embodiments. The features of the present disclosure may be realized and attained by practice or use of various methods, instrumentalities and combinations of the specific embodiments described below.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention. Like reference symbols in the various drawings indicate like elements. Wherein the content of the first and second substances,
FIG. 1 is an SEM image of a PVDF-HFP electrospun membrane in an example of the present invention;
FIG. 2 is a contact angle graph of a PVDF-HFP electrospun membrane in an example of the invention;
FIG. 3 is a DSC of 3PEG in example of the present invention;
FIG. 4 is a schematic diagram of a coaxial co-jet spinning device for preparing a co-jet spun electrospun membrane according to an embodiment of the invention;
FIG. 5 is an SEM image of a co-spun electrospun membrane according to an example of the invention;
FIG. 6 is a graph of contact angle of co-spun electrospun membranes in an example of the invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that if the terms "first", "second", etc. are used in the description and claims of the present invention and in the accompanying drawings, they are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances in order to facilitate the description of the embodiments of the invention herein. Furthermore, if the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In the present invention, if the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. are referred to, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. These terms are used primarily to better describe the invention and its embodiments and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.
Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the present invention can be understood by those skilled in the art as appropriate.
In addition, in the present invention, the terms "mounted," "disposed," "provided," "connected," "sleeved," and the like should be construed broadly if they are referred to. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
The embodiment of the invention discloses a co-jet spinning lithium ion battery diaphragm.
As shown in fig. 1 to 6, the co-spray lithium ion battery separator may mainly include an electrospun membrane and a modifying substance attached to the electrospun membrane. The electrospun membrane is of a porous skeleton structure. The modified substance is attached to the electrospun membrane in a random structure. Wherein the electrospun membrane serves as a flexible substrate framework and provides porous mechanical support; the modified substance is attached to the surface of the electrospun membrane, so that the compatibility of the electrospun membrane and electrolyte is improved, and the modified substance is used as a binder to adhere adjacent electrospun fiber membranes together. Preferably, the electrospun membrane has a thickness of 10-100 μm.
Illustratively, the electrospun film may be one or more of a polyolefin film, a polyvinylidene fluoride and copolymers thereof film, a polyethylene terephthalate film, a polystyrene film, a polyphenylene ether film, a polystyrene film, and a polyimide film.
The modified substance needs to have good compatibility with the electrolyte, good adhesion, excellent chemical and electrochemical stability, high conductivity and the like.
Illustratively, the modifying species may be one or more of a branched modified polymer, a hyperbranched modified polymer, and modified organic-inorganic nanoparticles.
According to the co-jet spinning lithium ion battery diaphragm provided by the embodiment of the invention, the compatibility of a single polymer and an electrolyte is improved by introducing the modified substance on the surface of the electrospinning fiber, and the operability and mechanical property of the diaphragm are improved by adhering adjacent fibers of the electrospinning film; the modified substance is introduced by adopting a co-jet spinning method, so that the problems of membrane size shrinkage, solvent residue, uneven adhesion and the like caused by solvent volatilization of the composite membrane prepared by the traditional membrane dipping method can be solved, and the porous membrane is prepared. Thus, the properties such as wettability, thermal stability, mechanical strength and the like of the single polymer electrospun membrane can be further improved through surface adhesion modification.
The embodiment of the invention also discloses a preparation method of the co-jet spinning lithium ion battery diaphragm.
The preparation method of the co-jet spinning lithium ion battery diaphragm comprises the following steps:
preparing an electrospinning solution: adding the high molecular raw material into the first solvent, and mechanically stirring and dissolving to obtain the electrospinning solution.
Preparing an electric spraying liquid: and dissolving the modified substance in a second solvent, and mechanically stirring to obtain the electro-spray liquid.
Preparing a co-jet spinning lithium ion battery diaphragm: and (3) preparing the co-jet spinning lithium ion battery diaphragm from the electro-spinning solution and the electro-spraying solution in a coaxial co-jet spinning mode. Respectively adding the electrospinning solution and the electronic spraying solution into an injector, wherein the electrospinning solution is connected with a core needle head, the electronic spraying solution is connected with a shell spray head, and the electronic spraying solution is connected with an electrospinning device for standby; and adjusting the distance between the coaxial co-jet spinning needle and the receiving roller and the solution flow rate, wrapping the outer wall of the core nozzle by the spinning solution when small liquid drops are formed below the core nozzle, turning on a high-voltage power supply, adjusting the voltage, and preparing the lithium ion composite diaphragm.
The polymer material may be one or more selected from polyolefin (PP, PE), polyvinylidene fluoride (PVDF) and its copolymer, polyethylene terephthalate (PET), Polystyrene (PS), polyphenylene oxide (PPO), polystyrene, and Polyimide (PI).
Wherein the mass fraction of the high molecular raw material in the electrospinning liquid is 10-20%.
The modified substance is one or more of branched modified polymer, hyperbranched modified polymer and modified organic-inorganic nanoparticles.
The following provides a specific example of the preparation method of the co-spun lithium ion battery separator of the present invention.
The preparation method of the co-jet spinning lithium ion battery diaphragm mainly comprises the following steps:
preparing an electrospinning solution: will MW＝4×105g mol-1Polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) was added in a volume ratio of 3: 1, fully stirring in a mixed solution of acetone and N-N dimethylformamide to prepare a polymer solution with the mass fraction of 16% to prepare an electrospinning solution;
preparing an electric spraying liquid: dissolving three-arm branched polyethylene glycol methacrylate (3PEG) in acetone to prepare 6 wt% of uniform solution, and mechanically stirring to prepare an electric spray liquid;
preparing a co-jet spinning lithium ion battery diaphragm: respectively adding the spinning solution and the electric spraying solution into a 5ml injector, adopting a coaxial co-spraying spinning needle, connecting the electric spinning solution with a core needle, connecting the electric spraying solution with a shell needle, and pumping the injector for 1.2ml h-1Injection rate of (2) promoting solutionSetting voltage to 18kV by using DC high-voltage generator as high-voltage electrostatic field device, setting cylindrical roller as receiving plate, and rotating speed of the roller at 500r &-1The vertical distance from the roller to the core needle is 15cm, and the core needle is lower than the shell needle by a certain length so as to ensure that the electrospinning filament is wrapped with the three-arm branched polyethylene glycol methacrylate polymer; when small liquid drops are formed below the core nozzle, the spinning solution wraps the outer wall of the core nozzle, a high-voltage power supply is turned on, and voltage is adjusted, so that the electric spraying liquid and the spinning solution are sprayed and spun simultaneously to prepare the lithium ion composite diaphragm; and after spinning is finished, drying the composite diaphragm in a vacuum drying oven at 40 ℃ for 24h to obtain the lithium ion battery diaphragm.
The prepared PVDF-HFP electrospun membrane is subjected to morphology analysis by a scanning electron microscope (SEM, FEI Quanta 200SEM), and an SEM image is shown in figure 1, and it can be seen from the SEM image that the prepared electrospun membrane has a uniformly distributed porous structure and uniform fiber diameters in the membrane. The PVDF-HFP electrospun membrane was tested for surface wettability using a contact angle test system (JC2000A) and the contact angle with water at room temperature is shown in FIG. 2.
In this embodiment, a schematic diagram of a membrane prepared by a coaxial co-jet spinning device is shown in fig. 4, a scanning electron microscope (SEM, FEI Quanta 200SEM) is used to analyze the morphology of the prepared co-jet spinning membrane, and an SEM image is shown in fig. 5. The surface wettability of the composite separator was tested using a contact angle test system diagram (JC2000A), and the contact angle with water at room temperature is shown in fig. 6, where the composite separator showed better wettability than a single PVDF-HFP electrospun film due to the 3PEG surface attachment.
In this example, the preparation method of the three-arm branched polyethylene glycol methacrylate (3PEG) specifically includes the following steps:
the macroinitiator tris (2-bromoisobutyrate) propane (TMPBr) was added to the polymerization flask under nitrogen atmosphere3) (0.07g), polyethylene glycol methacrylate (PEGMA) (5.4g,18mmol), dry toluene (5mL) and 1,1,4,7,10, 10-hexamethyltriethylenetetramine (ligand HMTETA) (82.5mg,0.36mmol) and finallyAdding CuBr2(51.5mg,0.36 mmol). The solution was subjected to three repeated freeze-pump-thaw cycles to remove oxygen and water from the reaction flask. The reaction was magnetically stirred in an oil bath at 85 ℃ for 6 hours, and at the end of the reaction, the flask was cooled in liquid nitrogen to terminate the polymerization. The polymer was repeatedly dissolved, precipitated in excess ether, filtered, then the copper salt was further removed by dialysis from the polymer, and dried under vacuum at 45 ℃ to give a colloidal solid, three-arm branched polyethylene glycol methacrylate (3 PEG).
The DSC chart of the prepared three-arm branched polyethylene glycol methacrylate (3PEG) is shown in figure 2, the polymer is in a completely amorphous state, the glass transition temperature is (-57.6 ℃), and the polymer has good segment motion capability at room temperature and is beneficial to the transmission of lithium ions.
The preparation method of the co-jet spinning lithium ion battery diaphragm adopts a co-jet spinning mode, and utilizes a coaxial co-jet spinning needle head to perform electro-spinning and simultaneously electro-spray modified substances. The preparation method is a preparation method of the composite diaphragm, and the method is changed into a co-spraying spinning mode, and the three-arm branched polyethylene glycol methacrylate (3PEG) is attached to the surface of the fiber filament in a spraying mode while the fiber filament is electrospun, so that the attachment uniformity of the three-arm branched polyethylene glycol methacrylate (3PEG) is improved.
The lithium ion battery diaphragm prepared by the method comprises an electrospinning film and three-arm branched polyethylene glycol methacrylate (3PEG) attached to the electrospinning film, the electrospinning film can provide a porous skeleton structure, the three-arm branched polyethylene glycol methacrylate (3PEG) attached to the fiber film is in a completely amorphous state, has high conductivity, is in a gel state after absorbing electrolyte, and the introduction of the three-arm branched polyethylene glycol methacrylate (3PEG) can improve the compatibility of the composite diaphragm and the electrolyte, improve the wettability of the diaphragm, increase the adhesion of adjacent fiber films, improve the mechanical property of the composite diaphragm and improve the thermal shrinkage of the composite diaphragm.
It should be noted that all of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except for mutually exclusive features and/or steps.
In addition, the above-described embodiments are exemplary, and those skilled in the art, having benefit of this disclosure, will appreciate numerous solutions that are within the scope of the disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.
Claims (9)
1. The co-jet spinning lithium ion battery separator is characterized by comprising an electrospun membrane and a modified substance attached to the electrospun membrane;
the electrospun membrane is of a porous skeleton structure;
the modifying substance is attached to the surface of the electrospun fiber in an amorphous shape.
2. The co-spun lithium ion battery separator of claim 1, wherein the electrospun membrane is one or more of a polyolefin membrane, a polyvinylidene fluoride and copolymers thereof membrane, an ethylene terephthalate membrane, a polystyrene membrane, a polyphenylene oxide membrane, a polystyrene membrane, and a polyimide membrane.
3. The co-spun lithium ion battery separator according to claim 1, wherein the electrospun membrane has a thickness of 10-100 μ ι η.
4. The co-spun lithium ion battery separator according to claim 1, wherein the modifying substance is one or more of a branched modified polymer, a hyperbranched modified polymer, and modified organic-inorganic nanoparticles.
5. The preparation method of the co-jet spinning lithium ion battery separator as claimed in one of claims 1 to 4, characterized in that the preparation method of the co-jet spinning lithium ion battery separator comprises the following steps:
preparing an electrospinning solution: adding a high molecular raw material into a first solvent, and mechanically stirring and dissolving to prepare an electrospinning solution;
preparing an electronic injection liquid: dissolving the modified substance in a second solvent, and mechanically stirring to obtain an electric spray liquid;
preparing a co-jet spinning lithium ion battery diaphragm: and (3) preparing the co-jet spinning lithium ion battery diaphragm from the electro-spinning solution and the electro-spraying solution in a coaxial co-jet spinning mode.
6. The method for preparing the co-jet spinning lithium ion battery separator according to claim 5, wherein the method for preparing the co-jet spinning lithium ion battery separator by the electrospinning solution and the electrospray solution in a coaxial co-jet spinning mode comprises the following steps:
respectively adding the electrospinning solution and the electro-spraying liquid into an injector, wherein the electrospinning solution is connected with a core needle head, the electro-spraying liquid is connected with a shell spray head, and the electro-spraying liquid is connected with an electrospinning device for standby;
and adjusting the distance between the coaxial co-jet spinning needle head and the receiving roller and the solution flow rate, wrapping the outer wall of the core nozzle with the electro-spinning solution when small liquid drops are formed below the core nozzle, turning on a high-voltage power supply, adjusting the voltage, and preparing the lithium ion composite diaphragm.
7. The method for preparing the co-jet spinning lithium ion battery separator according to claim 5, wherein the polymer raw material is one or more of polyolefin, polyvinylidene fluoride and copolymers thereof, polyethylene terephthalate, polystyrene, polyphenylene oxide, polystyrene and polyimide.
8. The preparation method of the co-jet spinning lithium ion battery separator according to claim 5, wherein the mass fraction of the polymer raw material in the electrospinning solution is 10% -20%.
9. The method for preparing the co-jet spinning lithium ion battery separator according to claim 5, wherein the modified substance is one or more of a branched modified polymer, a hyperbranched modified polymer and modified organic-inorganic nanoparticles.
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