CN111192994A - Heat-shrinkage-resistant polyethylene lithium battery diaphragm and preparation method thereof - Google Patents
Heat-shrinkage-resistant polyethylene lithium battery diaphragm and preparation method thereof Download PDFInfo
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- CN111192994A CN111192994A CN202010129221.4A CN202010129221A CN111192994A CN 111192994 A CN111192994 A CN 111192994A CN 202010129221 A CN202010129221 A CN 202010129221A CN 111192994 A CN111192994 A CN 111192994A
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- -1 polyethylene lithium Polymers 0.000 title claims abstract description 70
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 239000000843 powder Substances 0.000 claims abstract description 105
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 96
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 96
- 239000012621 metal-organic framework Substances 0.000 claims abstract description 83
- 239000010416 ion conductor Substances 0.000 claims abstract description 77
- 239000000463 material Substances 0.000 claims abstract description 50
- 239000004745 nonwoven fabric Substances 0.000 claims abstract description 46
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 54
- 239000003446 ligand Substances 0.000 claims description 54
- 229920000642 polymer Polymers 0.000 claims description 38
- 239000002904 solvent Substances 0.000 claims description 38
- 239000002002 slurry Substances 0.000 claims description 35
- 239000002243 precursor Substances 0.000 claims description 28
- 150000001868 cobalt Chemical class 0.000 claims description 27
- 239000000835 fiber Substances 0.000 claims description 26
- 239000011230 binding agent Substances 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 22
- 238000001035 drying Methods 0.000 claims description 21
- 238000002156 mixing Methods 0.000 claims description 19
- 238000005507 spraying Methods 0.000 claims description 17
- 239000004698 Polyethylene Substances 0.000 claims description 16
- QMKYBPDZANOJGF-UHFFFAOYSA-N benzene-1,3,5-tricarboxylic acid Chemical compound OC(=O)C1=CC(C(O)=O)=CC(C(O)=O)=C1 QMKYBPDZANOJGF-UHFFFAOYSA-N 0.000 claims description 16
- 230000008878 coupling Effects 0.000 claims description 16
- 238000010168 coupling process Methods 0.000 claims description 16
- 238000005859 coupling reaction Methods 0.000 claims description 16
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 claims description 16
- 229920000573 polyethylene Polymers 0.000 claims description 14
- 238000009987 spinning Methods 0.000 claims description 14
- 238000010041 electrostatic spinning Methods 0.000 claims description 12
- 238000013007 heat curing Methods 0.000 claims description 12
- 238000009998 heat setting Methods 0.000 claims description 12
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 11
- 239000012982 microporous membrane Substances 0.000 claims description 11
- 238000009960 carding Methods 0.000 claims description 10
- 238000003825 pressing Methods 0.000 claims description 10
- 239000004642 Polyimide Substances 0.000 claims description 9
- 238000001914 filtration Methods 0.000 claims description 9
- 229920001721 polyimide Polymers 0.000 claims description 9
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical group [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 claims description 8
- 229910001981 cobalt nitrate Inorganic materials 0.000 claims description 8
- 229910007822 Li2ZrO3 Inorganic materials 0.000 claims description 4
- 229910010488 Li4TiO4 Inorganic materials 0.000 claims description 4
- 229910007848 Li2TiO3 Inorganic materials 0.000 claims description 3
- 229910010565 Li4ZrO4 Inorganic materials 0.000 claims description 3
- 229910007562 Li2SiO3 Inorganic materials 0.000 claims description 2
- 229910052909 inorganic silicate Inorganic materials 0.000 claims description 2
- 239000007788 liquid Substances 0.000 abstract description 15
- 238000010521 absorption reaction Methods 0.000 abstract description 14
- 150000002500 ions Chemical class 0.000 abstract description 8
- 230000014759 maintenance of location Effects 0.000 abstract description 5
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 238000011065 in-situ storage Methods 0.000 abstract description 4
- 239000012784 inorganic fiber Substances 0.000 abstract description 4
- 239000002121 nanofiber Substances 0.000 abstract description 4
- 239000000243 solution Substances 0.000 description 45
- 239000011248 coating agent Substances 0.000 description 17
- 238000000576 coating method Methods 0.000 description 17
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 16
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical group CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 14
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 12
- 239000000853 adhesive Substances 0.000 description 10
- 230000001070 adhesive effect Effects 0.000 description 10
- 239000003792 electrolyte Substances 0.000 description 10
- 229920000098 polyolefin Polymers 0.000 description 8
- 229920003048 styrene butadiene rubber Polymers 0.000 description 8
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 7
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 7
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 7
- FWDBOZPQNFPOLF-UHFFFAOYSA-N ethenyl(triethoxy)silane Chemical compound CCO[Si](OCC)(OCC)C=C FWDBOZPQNFPOLF-UHFFFAOYSA-N 0.000 description 7
- 238000009740 moulding (composite fabrication) Methods 0.000 description 7
- 238000003756 stirring Methods 0.000 description 7
- 239000002033 PVDF binder Substances 0.000 description 5
- 239000002131 composite material Substances 0.000 description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000013329 compounding Methods 0.000 description 4
- 239000004743 Polypropylene Substances 0.000 description 3
- 229920006231 aramid fiber Polymers 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 239000010954 inorganic particle Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000001523 electrospinning Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- NKSJNEHGWDZZQF-UHFFFAOYSA-N ethenyl(trimethoxy)silane Chemical compound CO[Si](OC)(OC)C=C NKSJNEHGWDZZQF-UHFFFAOYSA-N 0.000 description 1
- WOXXJEVNDJOOLV-UHFFFAOYSA-N ethenyl-tris(2-methoxyethoxy)silane Chemical compound COCCO[Si](OCCOC)(OCCOC)C=C WOXXJEVNDJOOLV-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000009775 high-speed stirring Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000005213 imbibition Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 239000013110 organic ligand Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Nanotechnology (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Composite Materials (AREA)
- Cell Separators (AREA)
Abstract
The invention relates to a heat-shrinkage-resistant polyethylene lithium battery diaphragm and a preparation method thereof, belonging to the technical field of lithium ion battery diaphragms. The invention aims to provide a heat-shrinkage-resistant polyethylene lithium battery diaphragm and a preparation method thereof. According to the preparation method, the metal organic framework powder loaded with the lithium ion conductor is obtained through in-situ reaction and is compounded with the heat-resistant non-woven fabric containing the inorganic porous nanofiber with high specific surface area to form a high-temperature-resistant framework with high ion passing rate, the heat resistance and the mechanical property of the whole diaphragm are improved by the non-woven fabric framework containing the inorganic fiber and the metal organic framework material, and the heat shrinkage rate of the diaphragm is reduced; and further, the diaphragm has good liquid absorption and retention capacity by virtue of a porous structure rich in a metal organic framework, and can form a three-dimensional network structure with a lithium ion conductor, so that the ion passing rate is improved, and the charge and discharge performance of the battery is improved.
Description
Technical Field
The invention relates to a heat-shrinkage-resistant polyethylene lithium battery diaphragm and a preparation method thereof, belonging to the technical field of lithium ion battery diaphragms.
Background
Lithium ion batteries operate primarily by movement of lithium ions between a positive electrode and a negative electrode. Between the positive and negative electrodes of a lithium ion battery is a layer of film material, commonly referred to as a separator, which is an important component of the lithium ion battery. The separator has two basic functions: isolating the positive and negative electrodes to prevent short circuit in the battery; can be wetted by the electrolyte to form a channel for ion migration. The following characteristics should be provided in practical application: (1) the insulation of electrons; (2) high electrical conductivity; (3) good mechanical property, can be used for mechanical manufacturing treatment; (4) the thickness is uniform; (5) the amount of dimensionally stable deformation is small when heated.
The performance of the diaphragm is related to the void ratio, the pore size and distribution, the air permeability, the thermal performance, the mechanical performance and the like. Because the polyolefin material diaphragm has the advantages of high tear strength, good acid and alkali resistance, low material price and the like, most of diaphragms used by the lithium ion battery at present mainly comprise a PP (polypropylene) diaphragm, a PE (polyethylene) diaphragm, a PP/PE double-layer or three-layer composite diaphragm and the like, the production process is relatively mature, and the domestic industry is rapidly developed in recent years. But polyolefin diaphragm still has more defects, the dry method uniaxial stretching polyolefin diaphragm is easier to shrink thermally than the wet method biaxial stretching diaphragm, and experiments prove that the shrinkage rate of the uniaxial stretching diaphragm exceeds 1% after being treated for 4 hours at 85 ℃; in the high-power discharge process, the local temperature of the battery rises rapidly, when the temperature is close to the melting starting point of the diaphragm, the positive and negative pole pieces can be contacted by thermal contraction, and the instant heat generation is a huge potential danger. Therefore, it is required to modify a polyolefin separator.
At present, the methods for modifying the polyolefin diaphragm mainly comprise coating, compounding and the like.
The Chinese patent with application number 201610149926.6 discloses a composite lithium ion battery diaphragm material and a preparation method thereof. The battery diaphragm material is of a three-layer structure, wherein the first layer and the third layer are polymer porous films, and inorganic particles are attached to the opposite sides of the two polymer porous films; the intermediate layer is a nonwoven impregnated with a polymeric binder. The preparation method comprises the following steps: firstly, coating inorganic nano particles uniformly dispersed in a volatile solvent on a glass plate, and coating a polymer solution on the glass plate after the solvent is volatilized to obtain a polymer porous film with one side attached with the inorganic particles; and finally, carrying out hot rolling compounding on the porous film attached with the inorganic particles and the non-woven fabric impregnated with the polymer adhesive. The battery diaphragm material with the sandwich-like structure provided by the invention has the excellent characteristics of high liquid absorption rate, uniform pore size distribution, good wettability, good heat resistance and the like, improves the interface stability with an electrode material, and improves the safety performance, the cycle performance and the rate capability of a battery.
The Chinese patent with application number 201510967229.7 discloses a composite coating lithium ion battery diaphragm and a preparation method thereof. The composite coating lithium ion battery diaphragm consists of a base film, an aramid fiber coating coated on one side of the base film and a PVDF coating coated on the other side of the base film, wherein the aramid fiber coating is obtained by coating, soaking and drying aramid fiber slurry, and the thickness of the coating is 0.5-4 mu m; the PVDF coating is obtained by coating and drying aqueous PVDF slurry, and the thickness of the coating is 0.1-2 mu m. The invention also provides a preparation method of the diaphragm. The diaphragm provided by the invention has the characteristics of good thermal property and mechanical property of the aramid coating, good wettability and liquid retention of the PVDF coating to an electrolyte, effective bonding of a battery and a pole piece, and small environmental pollution, and is beneficial to preparing a lithium ion battery with longer cycle life and higher safety. Tests show that the diaphragm has good air permeability, liquid absorption rate, thermal shrinkage and tensile strength, and the lithium ion battery prepared by the diaphragm can obviously prolong the cycle life of the battery.
In summary, the existing polyolefin separator has poor electrolyte wettability and thermal stability, and even if the existing polyolefin separator is modified by coating, compounding and other methods, the use temperature of the existing polyolefin separator is not more than 150 ℃, otherwise, the contact short circuit of a positive electrode and a negative electrode can be caused by the thermal shrinkage of the separator.
Disclosure of Invention
The invention provides a heat-shrinkage-resistant polyethylene lithium battery diaphragm and a preparation method thereof, aiming at the defects of poor heat resistance, poor wettability, easy thermal deformation and poor ionic conductivity of the existing lithium battery polymer diaphragm.
The invention solves the first technical problem by providing a preparation method of a polyethylene lithium battery diaphragm with heat shrinkage resistance.
The preparation method of the heat-shrinkage-resistant polyethylene lithium battery diaphragm comprises the following steps:
a. preparation of heat-resistant non-woven fabric: carrying out surface coupling treatment on the nano-scale inorganic porous fiber, dispersing the nano-scale inorganic porous fiber in a solution of a heat-resistant polymer to prepare a spinning solution, and carrying out electrostatic spinning, carding to form a net and pressing to obtain a heat-resistant non-woven fabric;
b. preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1: 0.5-1: 30-50; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting for 6-10 h at 60-250 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 1-5 mL;
c. preparing a high-temperature-resistant framework layer: b, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of the two sides of the heat-resistant non-woven fabric obtained in the step a, and drying to obtain a high-temperature-resistant framework layer; wherein, in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 20-40%, and the weight percentage of the binder is 3-8%;
d. preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
According to the method, the metal organic framework powder loaded with the lithium ion conductor is obtained through in-situ reaction and is compounded with the heat-resistant non-woven fabric containing the inorganic porous nanofiber with high specific surface area to form a high-temperature-resistant framework with high ion passing rate, the heat resistance and the mechanical property of the whole diaphragm are improved by the non-woven fabric framework containing the inorganic fiber and the metal organic framework material, and the heat shrinkage rate of the diaphragm is reduced; and further, the diaphragm has good liquid absorption and retention capacity by virtue of a porous structure rich in a metal organic framework, and can form a three-dimensional network structure with a lithium ion conductor, so that the ion passing rate is improved, and the charge and discharge performance of the battery is improved.
Wherein, the step a is a process for preparing the heat-resistant non-woven fabric. Carrying out surface coupling treatment on the nano-scale inorganic porous fiber, dispersing the nano-scale inorganic porous fiber in a solution of a heat-resistant polymer to prepare a spinning solution, and carrying out electrostatic spinning, carding to form a net and pressing to obtain the heat-resistant non-woven fabric.
The surface coupling treatment commonly used in the art is suitable for the present invention, and preferably, the surface coupling treatment is performed on the nano-scale inorganic porous fiber by using a silane coupling agent. The molecular structural formula of the silane coupling agent is generally Y-R-Si (OR)3The silane coupling agent is adopted to modify the nanoscale inorganic porous fiber, so that the nanoscale inorganic porous fiber can be more firmly and uniformly dispersed, the common silane coupling agent is suitable for the invention, such as A151 (vinyl triethoxysilane), A171 (vinyl trimethoxysilane), A172 (vinyl tris (β -methoxyethoxy) silane) and the like, as the conventional coupling treatment, the use amount of the coupling agent is preferably 1-3% of the weight of the nanoscale inorganic porous fiber, and the surface coupling treatment adopts high-speed stirring equipment, such as stirring treatment for 30min at the rotating speed of 800rpm by using a high-speed mixer.
The heat-resistant polymer is a polymer material which can maintain the main physical properties of the polymer material under the condition of continuous use at 250 ℃, and the heat-resistant polymer is preferably polyimide, and can greatly improve the heat resistance of the diaphragm by adopting the heat-resistant polymer as a raw material for electrostatic spinning.
Dissolving a heat-resistant polymer in a solvent commonly used in the field, wherein the selection of the solvent is not particularly limited, obtaining a solution of the heat-resistant polymer, and then dispersing nano-scale inorganic porous fibers in the solution to prepare a spinning solution for electrostatic spinning. The electrospinning may be performed by a method commonly used in the art and by a electrospinning device commonly used in the art. The mass ratio of the nano inorganic porous fiber subjected to coupling treatment in the spinning solution to the heat-resistant polymer to the solvent is 1-3: 10-20: 80-120.
And the step b is mainly used for preparing the metal organic framework material powder loaded with the lithium ion conductor powder. Dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; and mixing the metal organic framework precursor solution with the lithium ion conductor powder, reacting for 6-10 h at 60-250 ℃ to ensure that the lithium ion conductor powder is dispersed and loaded in the metal organic framework material powder, and then filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder.
The Metal-Organic Frameworks (MOF) is a novel porous network structure material formed by Metal ions and Organic ligands through coordination connection, and the MOF has the following unique and potential advantages of large specific surface area of ①, no dead volume of ②, large porosity, firm and flexible and adjustable ③ framework, and regular ④ pores, so that the transfer rate of guest molecules in the MOF is high.
Preferably, the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid.
Preferably, in the step b, the weight ratio of the soluble cobalt salt, the first ligand, the second ligand and the dimethylformamide is 1:0.7:0.8: 40.
Preferably, in the step b, the lithium ion conductor is Li2ZrO3、Li4ZrO4、Li2TiO3、Li4TiO4、Li2SiO3、Li4SiO4At least one of (1).
Preferably, in the step b, the mass-to-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 3 mL.
And c, preparing the high-temperature-resistant framework layer, and compounding the metal organic framework material powder loaded with the lithium ion conductor powder and the heat-resistant non-woven fabric to obtain the high-temperature-resistant framework layer. Specifically, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the two side surfaces of the heat-resistant non-woven fabric obtained in the step a, and drying to obtain the high-temperature-resistant framework layer.
The solvent is mainly used for preparing the slurry, and may be an organic solvent commonly used in the art, such as chloroform, tetrahydrofuran, and the like. The binder mainly plays a role in binding, so that the metal organic framework material powder loaded with the lithium ion conductor powder is coated on the surface of the heat-resistant non-woven fabric to obtain the high-temperature-resistant framework layer, and the binder is preferably one of polyvinylidene fluoride, polytetrafluoroethylene and styrene butadiene rubber.
In the step, the preparation of the slurry is critical, preferably, the slurry contains 30 wt% of the metal organic framework material powder loaded with the lithium ion conductor powder and 5 wt% of the binder.
And d, preparing the polyethylene lithium battery diaphragm with heat shrinkage resistance. And coating the adhesive on the polyethylene microporous membrane layer, then adhering the polyethylene microporous membrane layer coated with the adhesive on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm. Namely, polyethylene microporous films are bonded on two surfaces of the high-temperature resistant framework layer, and the diaphragm is obtained after curing.
Preferably, the temperature of the heat setting and curing is 80-85 ℃, and the time is 4-8 h.
The invention solves a second technical problem by providing a polyethylene lithium battery diaphragm with heat shrinkage resistance.
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by adopting the preparation method of the heat-shrinkage-resistant polyethylene lithium battery diaphragm. The diaphragm is a three-layer composite film, the upper layer and the lower layer are both polyethylene microporous films, and the middle layer is a high-temperature-resistant framework layer. The metal organic framework powder loaded with the lithium ion conductor is obtained through in-situ reaction, and is compounded with the heat-resistant non-woven fabric containing the inorganic porous nano-fiber with high specific surface area to form a high-temperature-resistant framework layer with high ion passing rate, so that the diaphragm has good thermal stability, good liquid absorption and retention capacity and good ionic conductivity.
Compared with the prior art, the invention has the following beneficial effects:
according to the method, the metal organic framework powder loaded with the lithium ion conductor is obtained through in-situ reaction and is compounded with the heat-resistant non-woven fabric containing the inorganic porous nanofiber with high specific surface area to form a high-temperature-resistant framework with high ion passing rate, the heat resistance and the mechanical property of the whole diaphragm are improved by the non-woven fabric framework containing the inorganic fiber and the metal organic framework material, and the heat shrinkage rate of the diaphragm is reduced; and further, the diaphragm has good liquid absorption and retention capacity by virtue of a porous structure rich in a metal organic framework, and can form a three-dimensional network structure with a lithium ion conductor, so that the ion passing rate is improved, and the charge and discharge performance of the battery is improved.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.
Example 1
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by the following method, and specifically comprises the following steps:
a. preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:0.5:1: 30; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting at 105 ℃ for 10h, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 1 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li2ZrO3。
c. Preparing a high-temperature-resistant framework layer: mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 3 mu m, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 20%, and the weight percentage of the binder is 5%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 8 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 37 mu m, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.5%; the diaphragm is immersed in 1mol/L electrolyte of ethylene carbonate/dimethyl carbonate/diethyl carbonate (the mass ratio is 1: 1) of lithium hexafluorophosphate for 24h, the liquid absorption rate is 368.4%, and the lithium ion conductivity of the surface of the diaphragm is 1.93 mS/cm by adopting an electrochemical workstation.
Example 2
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by the following method, and specifically comprises the following steps:
a. preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:1:0.5: 50; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting for 6 hours at 100 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 5 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li4TiO4。
c. Preparing a high-temperature-resistant framework layer: mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 3 mu m, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 40%, and the weight percentage of the binder is 3%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 4 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 37 mu m, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.5%; the diaphragm is immersed in 1mol/L electrolyte of lithium hexafluorophosphate, ethylene carbonate/dimethyl carbonate/diethyl carbonate (the mass ratio is 1: 1) for 24h, the liquid absorption rate is 369.1%, and the lithium ion conductivity of the surface of the diaphragm is 1.89mS/cm when the diaphragm is tested by an electrochemical workstation.
Example 3
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by the following method, and specifically comprises the following steps:
a. preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt with first ligand and second ligand in dimethylObtaining a metal organic framework precursor solution in formamide; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:0.6:0.7: 35; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting for 7 hours at 100 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 2 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li2TiO3。
c. Preparing a high-temperature-resistant framework layer: b, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 4 microns, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 25%, and the weight percentage of the binder is 8%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 5 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 40 μm, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.4%; the diaphragm is immersed in an electrolyte of 1mol/L lithium hexafluorophosphate, ethylene carbonate/dimethyl carbonate/diethyl carbonate (the mass ratio is 1: 1) for 24h, the liquid absorption rate is 374.8%, and the lithium ion conductivity of the surface of the diaphragm is 1.98mS/cm by adopting an electrochemical workstation.
Example 4
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by the following method, and specifically comprises the following steps:
a. preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:0.7:0.9: 45; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting at 105 ℃ for 9 hours, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 4 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li4TiO4。
c. Preparing a high-temperature-resistant framework layer: b, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 5 microns, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 35%, and the weight percentage of the binder is 6%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 7 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 42 μm, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.4%; the diaphragm was immersed in an electrolyte of 1mol/L lithium hexafluorophosphate, ethylene carbonate/dimethyl carbonate/diethyl carbonate (mass ratio 1: 1) for 24 hours, and the liquid absorption rate obtained was 373.1%, and the surface lithium ion conductivity thereof was 1.95mS/cm as measured by an electrochemical workstation.
Example 5
The heat-shrinkage-resistant polyethylene lithium battery diaphragm is prepared by the following method, and specifically comprises the following steps:
a. preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:0.8:0.6: 40; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting for 8 hours at 100 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 3.5 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li4ZrO4。
c. Preparing a high-temperature-resistant framework layer: b, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 5 microns, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 30%, and the weight percentage of the binder is 4%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 85 ℃ for 6 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 42 μm, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.3%; the diaphragm is immersed in 1mol/L electrolyte of ethylene carbonate/dimethyl carbonate/diethyl carbonate (the mass ratio is 1: 1) of lithium hexafluorophosphate for 24h, the liquid absorption rate is 379.5%, and the lithium ion conductivity of the surface of the diaphragm is 2.07mS/cm when tested by an electrochemical workstation.
Comparative example 1
a. Preparing the non-woven fabric: preparing a spinning solution from a heat-resistant polymer; wherein the mass ratio of the heat-resistant polymer to the solvent is 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1:0.5:1: 30; mixing the metal organic framework precursor solution with the lithium ion conductor powder, reacting for 10h at 105 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass volume of the lithium ion conductor powder and the metal organic framework precursor solutionThe ratio is 1 g: 1 mL; the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid; the lithium ion conductor is Li2ZrO3。
c. Preparing a high-temperature-resistant framework layer: mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of two sides of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side of the heat-resistant non-woven fabric is 3 mu m, and drying to obtain a high-temperature-resistant framework layer; in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 20%, and the weight percentage of the binder is 5%. The solvent is chloroform; the adhesive is styrene butadiene rubber.
d. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 8 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
The thickness of the obtained diaphragm is 37 mu m, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 1.2 percent; the diaphragm was immersed in an electrolyte of 1mol/L lithium hexafluorophosphate, ethylene carbonate/dimethyl carbonate/diethyl carbonate (mass ratio 1: 1) for 24 hours, and the liquid absorption rate was 237.1%, and the surface lithium ion conductivity thereof was 1.59 mS/cm as measured by an electrochemical workstation. Comparative example 1 no inorganic fiber was implanted in the heat-resistant spinning film, affecting heat shrinkage resistance and liquid absorption.
Comparative example 2
a. Preparation of heat-resistant non-woven fabric: adding a silane coupling agent of vinyltriethoxysilane and nano-scale porous alumina fibers into a high-speed mixer, stirring at the rotating speed of 800rpm for 30min, performing surface coupling treatment, and dispersing in a solution of a heat-resistant polymer to prepare a spinning solution; wherein the mass ratio of the nano porous alumina fiber to the heat-resistant polymer to the solvent is 2: 15: 80; electrostatic spinning, carding, forming a net and pressing at 70 ℃ to obtain heat-resistant non-woven fabric with the thickness of 20 mu m for later use; the heat-resistant polymer is polyimide; the solvent is N-methyl-2-pyrrolidone.
b. Preparing a high-temperature-resistant framework layer: mixing lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the two side surfaces of the heat-resistant non-woven fabric obtained in the step a, wherein the spraying thickness of one side is 3 microns, and drying to obtain a high-temperature-resistant framework layer; wherein, in the slurry, the weight percentage of the lithium ion conductor powder is 20 percent, and the weight percentage of the binder is 5 percent. The solvent is chloroform; the adhesive is styrene butadiene rubber.
c. Preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing at the temperature of 80 ℃ for 8 hours to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
Comparative example 2 does not use a metal organic framework to support the internal ion conductor, affecting the lithium ion conduction and imbibition capacity. The thickness of the obtained diaphragm is 37 mu m, the diaphragm is processed for 4 hours at 105 ℃, and the shrinkage rate is 0.5%; the separator was immersed in an electrolyte of 1mol/L lithium hexafluorophosphate, ethylene carbonate/dimethyl carbonate/diethyl carbonate (mass ratio 1: 1) for 24 hours, and the liquid absorption rate obtained was 159.9%, and the surface lithium ion conductivity thereof was 0.82mS/cm as measured by an electrochemical workstation.
Claims (10)
1. A preparation method of a polyethylene lithium battery diaphragm with heat shrinkage resistance is characterized by comprising the following steps:
a. preparation of heat-resistant non-woven fabric: carrying out surface coupling treatment on the nano-scale inorganic porous fiber, dispersing the nano-scale inorganic porous fiber in a solution of a heat-resistant polymer to prepare a spinning solution, and carrying out electrostatic spinning, carding to form a net and pressing to obtain a heat-resistant non-woven fabric;
b. preparing the metal organic framework material powder loaded with the lithium ion conductor powder: dissolving soluble cobalt salt, a first ligand and a second ligand in dimethylformamide to obtain a metal organic framework precursor solution; the weight ratio of the soluble cobalt salt to the first ligand to the second ligand to the dimethylformamide is 1: 0.5-1: 30-50; and mixing the metal organic framework precursor solution with lithium ion conductor powder, reacting for 6-10 h at 60-250 ℃, filtering and drying to obtain the metal organic framework material powder loaded with the lithium ion conductor powder, wherein the mass-volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 1-5 mL;
c. preparing a high-temperature-resistant framework layer: b, mixing the metal organic framework material powder loaded with the lithium ion conductor powder, a solvent and a binder to form slurry, uniformly spraying the slurry on the surfaces of the two sides of the heat-resistant non-woven fabric obtained in the step a, and drying to obtain a high-temperature-resistant framework layer; wherein, in the slurry, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 20-40%, and the weight percentage of the binder is 3-8%;
d. preparing a polyethylene lithium battery diaphragm with heat shrinkage resistance: and (3) bonding the polyethylene microporous membrane layers on the surfaces of the two sides of the high-temperature-resistant framework layer, and then performing heat setting and curing to obtain the heat-shrinkage-resistant polyethylene lithium battery diaphragm.
2. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: and in the step a, silane coupling agent is adopted to carry out surface coupling treatment on the nano inorganic porous fiber.
3. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step a, the heat-resistant polymer is polyimide; the mass ratio of the nano inorganic porous fiber subjected to coupling treatment in the spinning solution to the heat-resistant polymer to the solvent is 1-3: 10-20: 80-120.
4. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step b, the soluble cobalt salt is cobalt nitrate; the first ligand is trimesic acid; the second ligand is isophthalic acid.
5. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step b, the weight ratio of the soluble cobalt salt, the first ligand, the second ligand and the dimethylformamide is 1:0.7:0.8: 40.
6. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step b, the lithium ion conductor is Li2ZrO3、Li4ZrO4、Li2TiO3、Li4TiO4、Li2SiO3、Li4SiO4At least one of (1).
7. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step b, the mass volume ratio of the lithium ion conductor powder to the metal organic framework precursor solution is 1 g: 3 mL.
8. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the slurry in the step c, the weight percentage of the metal organic framework material powder loaded with the lithium ion conductor powder is 30%, and the weight percentage of the binder is 5%.
9. The method for preparing a polyethylene lithium battery separator resistant to thermal shrinkage according to claim 1, wherein: in the step d, the temperature of heat setting and curing is 80-85 ℃, and the time is 4-8 h.
10. A polyethylene lithium battery diaphragm of heat-resistant shrink which characterized in that: the preparation method of the polyethylene lithium battery separator with heat shrinkage resistance as defined in any one of claims 1 to 9.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111969163A (en) * | 2020-08-31 | 2020-11-20 | 重庆大学 | Lithium battery composite diaphragm, manufacturing method thereof and lithium battery |
| CN112321840A (en) * | 2020-11-06 | 2021-02-05 | 华南师范大学 | Metal organic framework material and preparation method and application thereof |
| CN112670664A (en) * | 2020-12-21 | 2021-04-16 | 广东微电新能源有限公司 | Diaphragm, preparation method thereof and chemical battery |
| CN113802118A (en) * | 2021-08-04 | 2021-12-17 | 西安理工大学 | A kind of preparation method of lithium metasilicate/nickel composite material |
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2020
- 2020-02-28 CN CN202010129221.4A patent/CN111192994A/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111969163A (en) * | 2020-08-31 | 2020-11-20 | 重庆大学 | Lithium battery composite diaphragm, manufacturing method thereof and lithium battery |
| CN112321840A (en) * | 2020-11-06 | 2021-02-05 | 华南师范大学 | Metal organic framework material and preparation method and application thereof |
| CN112670664A (en) * | 2020-12-21 | 2021-04-16 | 广东微电新能源有限公司 | Diaphragm, preparation method thereof and chemical battery |
| CN112670664B (en) * | 2020-12-21 | 2023-11-03 | 广东微电新能源有限公司 | Separator and preparation method thereof, chemical battery |
| CN113802118A (en) * | 2021-08-04 | 2021-12-17 | 西安理工大学 | A kind of preparation method of lithium metasilicate/nickel composite material |
| CN113802118B (en) * | 2021-08-04 | 2022-10-04 | 西安理工大学 | A kind of preparation method of lithium metasilicate/nickel composite material |
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