WO2019206283A1 - 聚合物隔膜及其制备方法和应用以及锂离子电池 - Google Patents

聚合物隔膜及其制备方法和应用以及锂离子电池 Download PDF

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WO2019206283A1
WO2019206283A1 PCT/CN2019/084568 CN2019084568W WO2019206283A1 WO 2019206283 A1 WO2019206283 A1 WO 2019206283A1 CN 2019084568 W CN2019084568 W CN 2019084568W WO 2019206283 A1 WO2019206283 A1 WO 2019206283A1
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hydrophilic
polymer
layer
porous
weight
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English (en)
French (fr)
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宣博文
金丽娜
曹晓东
吴金祥
单军
胡刚
何龙
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比亚迪股份有限公司
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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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • 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
    • H01M50/403—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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • 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
    • H01M50/443—Particulate 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
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing 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
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • 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
    • 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
    • H01M50/494—Tensile strength
    • 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
    • H01M50/497—Ionic conductivity
    • 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

Definitions

  • the present disclosure relates to a polymer membrane and a method and apparatus for its preparation, and to a lithium ion battery employing the polymer membrane.
  • Lithium-ion batteries are mainly composed of positive/negative materials, electrolytes, separators and battery casing packaging materials.
  • the separator is an important part of the lithium ion battery, which is used to separate the positive and negative electrodes to prevent internal short circuit of the battery; the diaphragm allows the electrolyte ions to pass freely, completing the electrochemical charging and discharging process.
  • the performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the rate performance, cycle performance and safety performance (high temperature resistance) of the battery.
  • the separator with excellent performance plays an important role in improving the overall performance of the battery.
  • the polyethylene and polypropylene microporous membranes prepared by mechanical stretching method are currently the main commercial lithium ion battery separators.
  • commercial microporous membrane shrinkage caused by closed cells near the melting temperature causes short circuit of the battery, which causes the battery to have the danger of burning and explosion at high temperature.
  • the polyolefin separator has poor adsorption to the electrolyte, which is not conducive to lithium ion during charging and discharging. Conduction.
  • polyethers such as polyethylene oxide
  • polyacrylonitriles such as polymethyl methacrylate and copolymers thereof
  • polyvinylidene fluoride are coated on both sides of the polyolefin microporous membrane.
  • a porous film of a polar polymer including polyvinylidene fluoride, and a vinylidene fluoride-hexafluoropropylene copolymer
  • the phase inversion method is one of the main methods for preparing a porous membrane, and mainly includes two forms: (1) solvent evaporation precipitation phase separation method; and (2) immersion precipitation phase separation method.
  • PVDF polyvinylidene fluoride
  • PVDF coating technology uses solvent evaporation precipitation phase separation method to make pores on the surface of polyolefin microporous membrane to obtain PVDF porous membrane.
  • the specific operation process is: dissolving or dispersing polyvinylidene fluoride in acetone.
  • porogen DMC dimethyl carbonate
  • the existing polyvinylidene fluoride (PVDF) coating technology uses low-boiling acetone as a solvent, and the operational safety needs to be improved.
  • the inventors of the present disclosure found in the research process that although the use of a high boiling solvent instead of acetone can improve the safety of operation, the performance of a lithium ion battery prepared by preparing a polyvinylidene fluoride polymer solution using a solvent having a high boiling point is markedly lowered. After research, the reason may be that the polyvinylidene fluoride polymer solution prepared by using a high boiling solvent is extremely permeable, and the polymer solution easily penetrates the separator to reach the other surface opposite to the coated surface.
  • the polyvinylidene fluoride-based polymer is also brought into the pores of the separator. Since the flowability and permeability of the polyvinylidene fluoride-based polymer are much lower than that of the organic solvent, the polyvinylidene fluoride-based polymerization carried by the organic solvent into the separator The material usually remains in the pores of the membrane, clogging the membrane, adversely affecting the permeability and porosity of the membrane, increasing the bulk impedance of the polymer membrane, reducing the ionic conductivity, and adversely affecting the performance of the finally prepared lithium ion battery.
  • the existing polyolefin separator surface generally forms a ceramic layer to improve the thermal stability of the separator and the ability to adsorb the electrolyte, even a polyolefin separator having the ceramic layer is difficult to block the polymer solution from penetrating the separator.
  • the inventors of the present disclosure conducted intensive studies on the problems in formulating a polyvinylidene fluoride-based polymer solution using a solvent having a high boiling point, and found that when a polyvinylidene fluoride-based polymer solution is prepared using a solvent having a high boiling point, Providing a hydrophilic retardation layer between a porous substrate (that is, a polyolefin porous film having a ceramic layer or not having a ceramic layer) and a polyvinylidene fluoride-based polymer can effectively inhibit a polyvinylidene fluoride-based polymer
  • the solution penetrates the hydrophilic retardation layer and enters the porous substrate, thereby effectively reducing the amount of the polyvinylidene fluoride-based polymer entering the porous substrate, improving the gas permeability and porosity of the polymer separator, and lowering the polymer.
  • the bulk impedance of the separator increases the ionic conductivity of the polymer separator, so that the
  • the present disclosure provides a polymer separator comprising a porous substrate; a hydrophilic retardation layer, the hydrophilic retardation layer being disposed on the porous substrate And a porous polar polymer bonding layer disposed on a surface of the hydrophilic retardation layer away from the porous substrate; and a porous polar polymer bonding layer
  • the porous polar polymer bonding layer has a pore diameter of 200 nm to 20 ⁇ m.
  • the present disclosure provides a method of preparing a polymer separator, the method comprising: coating a hydrophilic barrier slurry on one surface or opposite surfaces of a porous substrate a hydrophilic retardation coating layer, drying the hydrophilic retardation coating layer to form a hydrophilic retardation layer on a surface of the porous substrate; coating a polar polymer binder solution on the The hydrophilic retardation layer is away from the surface of the porous substrate to form a polar polymer binder coating, and the polar polymer binder coating is dried, in the hydrophilic retardation Forming a porous polar polymer bonding layer on the surface of the layer; or coating the hydrophilic barrier slurry on one surface or opposite surfaces of the porous substrate to form the hydrophilic barrier coating a layer, the polar polymer binder solution is coated on the surface of the hydrophilic barrier coating away from the porous substrate to form the polar polymer binder coating,
  • the present disclosure when formulating the polar polymer binder solution, either a low boiling point solvent (such as acetone) in the prior art or a high boiling point with higher operational safety can be used.
  • a low boiling point solvent such as acetone
  • a high boiling point solvent can also be used.
  • a high boiling point solvent it not only improves the operational safety, but also does not cause a significant drop in the performance of the lithium ion battery.
  • the present disclosure provides a lithium ion battery including a positive electrode tab, a negative electrode tab, and a polymer separator, wherein the polymer separator is the first aspect of the disclosure Or the polymeric separator of the third aspect.
  • FIG. 1 and 2 are photographs of the surface SEM topography of the hydrophilic retardation layer of the polymer separator prepared in Example 1-1, FIG. 1 is a photograph magnified 500 times, and FIG. 2 is a photograph magnified 5000 times.
  • FIG. 3 and 4 are SEM topographical images of the polymer separator prepared in Example 2-1A, FIG. 3 is a photograph magnified 500 times, and FIG. 4 is a photograph magnified 5000 times.
  • FIG. 5 and 6 are SEM topographical images of the polymer separator prepared in Example 2-1B, FIG. 5 is a photograph magnified 500 times, and FIG. 6 is a photograph magnified 5000 times.
  • FIG. 7 and 8 are photographs of the surface SEM topography of the polymer separator prepared in Comparative Example 1, FIG. 7 is a photograph magnified 500 times, and FIG. 8 is a photograph magnified 5000 times.
  • FIG. 9 and 10 are photographs of the surface SEM topography of the polymer separator prepared in Comparative Example 3, FIG. 9 is a photograph magnified 500 times, and FIG. 10 is a photograph magnified 5000 times.
  • Fig. 11 and Fig. 12 are photographs of SEM topography of the polymer separator side (Fig. 11) and the positive electrode side (Fig. 12) after the polymer separator prepared in Example 2-1A was peeled off from the positive electrode bonding contact surface.
  • FIG. 13 and FIG. 14 are photographs of SEM topography of the polymer separator side (FIG. 13) and the negative electrode side (FIG. 14) after the polymer separator prepared in Example 2-1A was peeled off from the negative electrode bonding contact surface.
  • FIG. 15 and FIG. 16 are graphs showing the peel strength test curves of the positive electrode and the polymer separator of the lithium ion battery prepared in Example 2-1A (FIG. 15) and Comparative Example 1 (FIG. 16), respectively.
  • FIG. 17 and 18 are graphs showing the peel strength test curves of the negative electrode and the polymer separator of the lithium ion battery prepared in Example 2-1A (FIG. 17) and Comparative Example 1 (FIG. 18), respectively.
  • the present disclosure provides a polymer separator comprising a porous substrate, a hydrophilic retardation layer, and a porous polar polymer bonding layer, the hydrophilic barrier a hysteresis layer is disposed on one surface or opposite surfaces of the porous substrate, and the porous polar polymer bonding layer is disposed on a surface of the hydrophilic retardation layer away from the porous substrate Or the hydrophilic retardation layer is disposed between the porous substrate and the porous polar polymer bonding layer.
  • the hydrophilic retardation layer is a retardation layer having hydrophilic properties.
  • the contact angle of the hydrophilic retardation layer with water may be 40° or less, for example, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8 °, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40.
  • the hydrophilic retardation layer has a contact angle with water of 20° or less.
  • the hydrophilic retardation layer has a contact angle with water of 2-18°, specifically 5-15°.
  • the contact angle is determined by the method specified in GB/T 30693-2014 plastic film and water contact angle measurement.
  • the hydrophilic retardation layer contains a binder and hydrophilic inorganic particles which are bonded to each other by the binder.
  • the hydrophilic inorganic particles may be hydrophilic Al 2 O 3 particles, hydrophilic SiO 2 particles, hydrophilic SnO 2 particles, hydrophilic ZrO 2 particles, hydrophilicity TiO 2 particles, hydrophilic SiC particles, hydrophilic Si 3 N 4 particles, hydrophilic CaO particles, hydrophilic MgO particles, hydrophilic ZnO particles, hydrophilic BaTiO 3 particles, hydrophilic LiAlO 2 particles And one or more of hydrophilic BaSO 4 particles.
  • the hydrophilic inorganic particles are one or both of hydrophilic Al 2 O 3 particles and hydrophilic SiO 2 particles.
  • the hydrophilic inorganic particles are one or both of gas phase hydrophilic SiO 2 particles, precipitation hydrophilic SiO 2 particles, and gas phase hydrophilic Al 2 O 3 particles. the above.
  • the hydrophilic inorganic particles may have a particle diameter of 1 nm to 10 ⁇ m, such as 1 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm.
  • the hydrophilic inorganic particles may have a particle diameter of from 1 nm to 5 ⁇ m. From the viewpoint of further improving the gas permeability and ionic conductivity of the polymer separator and the performance of the lithium ion battery using the polymer separator, in some specific embodiments, the hydrophilic inorganic particles have a particle diameter of 10 nm to 1 ⁇ m, In some embodiments, the hydrophilic inorganic particles have a particle diameter of 20 nm to 800 nm, and in some embodiments, the hydrophilic inorganic particles have a particle diameter of 50 nm to 350 nm.
  • the particle size described herein is the volume average particle diameter and is measured by a laser particle size analyzer.
  • the hydrophilic surface area of the inorganic particles may be 10-600m 2 / g, such as 10m 2 / g, 50m 2 / g, 100m 2 / g, 150m 2 / g, 200m 2 / g, 250m 2 / g, 300m 2 / g, 350m 2 / g, 400m 2 / g, 450m 2 / g, 500m 2 / g, 550m 2 / g or 600m 2 / g.
  • the hydrophilic inorganic particles have a specific surface area of 100 to 500 m 2 / g, in other specific embodiments, the hydrophilic inorganic particles have a specific surface area of 150-400 m 2 /g, and in some embodiments, the hydrophilic inorganic particles have a specific surface area of 200-400 m 2 / g. In still other embodiments, the hydrophilic inorganic particles have a specific surface area of from 250 to 390 m 2 /g.
  • the hydrophilic inorganic particles have a specific surface area of from 300 to 380 m 2 / g.
  • the specific surface area is determined by the method specified in the method for measuring the specific surface area of solid materials by the gas adsorption BET method of GB/T19587-2004.
  • the content of the hydrophilic inorganic particles may be 50 to 95% by weight, such as 50%, 55%, 60%, based on the total amount of the hydrophilic retardation layer. 65%, 70%, 75%, 80%, 85%, 90% or 95%. In some embodiments, the content of the hydrophilic inorganic particles may be 70-95% by weight. In other specific embodiments, the content of the hydrophilic inorganic particles may be 80-95% by weight, and some specific In an embodiment, the hydrophilic inorganic particles may be included in an amount of from 85 to 95% by weight.
  • the binder is used on the one hand to bind and fix the hydrophilic inorganic particles, and on the other hand, the ability of the polymer separator to adsorb the electrolyte can be further improved.
  • the binder may be an acrylate type polymer, a styrene-acrylate copolymer, polyvinylidene fluoride (vinylidene fluoride or vinylidene fluoride), vinylidene fluoride-hexafluoropropylene.
  • a copolymer an acrylonitrile-acrylate copolymer, a vinyl chloride-acrylate copolymer, and a butadiene-styrene copolymer.
  • the hydrophilic retardation layer may have a thickness of 0.1 to 3 ⁇ m, for example, 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1 ⁇ m, 1.1 ⁇ m, 1.2 ⁇ m, 1.3 ⁇ m, 1.4 ⁇ m, 1.5 ⁇ m, 1.6 ⁇ m, 1.7 ⁇ m, 1.8 ⁇ m, 1.9 ⁇ m, 2 ⁇ m, 2.1 ⁇ m, 2.2 ⁇ m, 2.3 ⁇ m, 2.4 ⁇ m, 2.5 ⁇ m, 2.6 ⁇ m, 2.7 ⁇ m, 2.8 ⁇ m, 2.9 ⁇ m, or 3 ⁇ m.
  • the hydrophilic retardation layer may have a thickness of 0.1 to 1 ⁇ m.
  • the hydrophilic retardation layer may have a thickness of 0.1 to 1 ⁇ m.
  • the porous substrate contains a porous polymer layer which can be used to swell the liquid electrolyte and transport lithium ions.
  • the porous polymer layer is a porous polyolefin layer, such as one or two of a porous polyethylene (PE) layer, a porous polypropylene (PP) layer, a porous polyethylene, and a porous polypropylene composite layer. More than one species.
  • the porous polyethylene and porous polypropylene composite layer may be a PE/PP/PE composite substrate layer.
  • the porous polymer layer may have a thickness of 1 to 50 ⁇ m, such as 1 ⁇ m, 5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, 45 ⁇ m or 50 ⁇ m.
  • the porous polymer layer may have a thickness of 5-20 ⁇ m. In other embodiments, the porous polymer layer may have a thickness of 8-15 ⁇ m.
  • the porous substrate may further contain a ceramic layer for improving thermal stability, mechanical properties, and electrolyte adsorption capacity of the porous polymer layer.
  • the ceramic particles in the ceramic layer may be selected from the group consisting of Al 2 O 3 , SiO 2 , SnO 2 , ZrO 2 , TiO 2 , SiC, Si 3 N 4 , CaO, MgO, ZnO, BaTiO. 3. Ceramic particles formed by sintering one or more of LiAlO 2 and BaSO 4 .
  • the ceramic layer may have a thickness of 1-5 ⁇ m, such as 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, 3.5 ⁇ m, 4 ⁇ m, 4.5 ⁇ m, or 5 ⁇ m. In some embodiments, the ceramic layer may have a thickness of 1.5-3 ⁇ m. In other specific embodiments, the thickness of the ceramic layer is greater than the thickness of the hydrophilic retardation layer.
  • the ceramic layer is disposed on one surface or opposite surfaces of the porous polymer layer.
  • a ceramic layer is disposed on one surface of the porous polymer layer, and the hydrophilic retardation layer is disposed on the other surface of the porous polymer layer, the hydrophilic retardation A layer is disposed on a surface of the ceramic layer, or the hydrophilic retardation layer is simultaneously disposed on the other surface of the porous polymer layer and on a surface of the ceramic layer.
  • the ceramic layer is disposed on opposite surfaces of the porous polymer layer, the hydrophilic retardation layer being disposed on a surface of the one-sided ceramic layer away from the porous polymer layer, or The hydrophilic retardation layer is simultaneously disposed on both sides of the ceramic layer away from the surface of the porous polymer layer.
  • the ceramic layer may be disposed between the porous polymer layer and the hydrophilic retardation layer, or a porous polymer layer may be disposed between the ceramic layer and the pro Between the aqueous retardation layers, a combination of the above two modes may also be used.
  • the porous polar polymer bonding layer serves to reduce the shrinkage ratio of the porous substrate in the vicinity of the melting temperature while functioning as a bonding, and the polymer separator and the positive electrode tab of the battery Or the negative electrode sheets are bonded together, and the ability of the porous substrate to adsorb the electrolyte can also be improved.
  • the polar polymer in the porous polar polymer bonding layer may be a polar polymer capable of achieving the above functions, and specific examples thereof may include, but are not limited to, polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluorocarbon.
  • PVDF-HFP propylene copolymer
  • VDF-HFP propylene copolymer
  • vinylidene fluoride and hexafluoropropylene a copolymer called vinylidene fluoride and hexafluoropropylene
  • vinylidene fluoride-acrylate copolymer or a copolymer of vinylidene fluoride and acrylate
  • the porous polar polymer bonding layer may have a thickness of 0.1 to 10 ⁇ m, such as 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, and 0.8 ⁇ m. , 0.9 ⁇ m, 1.0 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m.
  • the porous polar polymeric tie layer may have a thickness of 0.2-5 ⁇ m.
  • the porous polar polymeric tie layer may have a thickness of 0.7. - 3 ⁇ m, in still other embodiments of the present disclosure, the porous polar polymer bonding layer may have a thickness of 0.8 to 1.5 ⁇ m.
  • the pores in the porous polar polymer bonding layer include pores having a first pore diameter and pores having a second pore diameter
  • the first pore diameter may be 5-20 ⁇ m, specifically, 5 ⁇ m, 6 ⁇ m 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, 16 ⁇ m, 17 ⁇ m, 18 ⁇ m, 19 ⁇ m, 20 ⁇ m, etc.
  • the second pore diameter may be 200 nm to 2 ⁇ m, specifically, 200 nm, 300 nm, 400 nm, 500 nm 600 nm, 700 nm, 800 nm, 900 nm, 1 ⁇ m, 1.1 ⁇ m, 1.2 ⁇ m, 1.3 ⁇ m, 1.4 ⁇ m, 1.5 ⁇ m, 1.6 ⁇ m, 1.7 ⁇ m, 1.8 ⁇ m, 1.9
  • the first pore size is 5-10 ⁇ m and the second pore size is 200 nm-2 ⁇ m.
  • the porous polar polymer bonding layer in the polymer separator according to the present disclosure has a two-stage pore structure, and the inventors of the present disclosure have occasionally found that a large pore diameter can reduce the contact area of the polymer separator with the positive and negative surfaces. Does not block the transport of lithium ions, but its pore size is too large, which will result in poor strength of the bonding layer, poor uniformity of the pore morphology on the bonding layer, and conductivity and adhesion between the polymer separator and the positive and negative electrodes.
  • the two-stage pore size combination of the porous polar polymer bonding layer provided by the present disclosure effectively solves the above technical problems and further improves battery performance. It should be noted that the pore size described herein is a number average pore diameter.
  • the porous polar polymeric tie layer has a porosity of 20-80%, such as 20%, 30%, 40%, 50%, 60%, 70%, 80%, and the like.
  • the porous polar polymeric tie layer comprises a through hole extending through the porous polar polymeric tie layer.
  • the pore diameter in the porous polar polymer bonding layer is qualitatively determined according to the SEM image of the surface of the porous polar polymer bonding layer; the porosity of the porous polar polymer bonding layer is n-butanol absorption method,
  • the separator was immersed in a solvent of a known density of n-butanol, and the volume of the void occupied by the liquid was calculated as the porosity of the separator by measuring the difference in mass before and after the impregnation of the separator.
  • the hydrophilic retardation layer and the porous polar polymer bonding layer may be disposed on at least one surface of the porous substrate, specifically, the hydrophilic retardation layer And the porous polar polymer bonding layer may be disposed on one side of the porous substrate or on both sides of the porous substrate.
  • the porous polar polymer bonding layer is attached to the surface of the hydrophilic retardation layer, that is, disposed on the hydrophilic retardation layer away from the porous substrate. on the surface.
  • the polymer membrane is composed of a porous substrate, a hydrophilic retardation layer, and a porous polar polymer bonding layer, the porous substrate being a porous polymer a layer, the hydrophilic retardation layer is attached to a surface of the porous substrate, and the porous polar polymer bonding layer is attached to a surface of the hydrophilic retardation layer.
  • the hydrophilic retardation layer and the porous polar polymer bonding layer may be sequentially disposed on one surface of the porous substrate (ie, the polymer separator has the following structure: porous polymer layer
  • the polymer membrane of the present disclosure is composed of a porous substrate, a hydrophilic retardation layer, and a porous polar polymer bonding layer, which is porously polymerized.
  • the layer consists of a layer of matter and a layer of ceramic.
  • the ceramic layer is attached to the surface of the porous polymer layer, and the hydrophilic retardation layer is attached to the surface of the ceramic layer, the porous polar polymer
  • the bonding layer is attached to the surface of the hydrophilic retardation layer (that is, the polymer separator has the following structure: porous polymer layer
  • the porous polymer layer is attached to a surface of the ceramic layer, the hydrophilic retardation layer is attached to a surface of the porous polymer layer, and the porous polar polymer is bonded A layer is attached to the surface of the hydrophilic retardation layer (that is, the polymer separator has the following structure: ceramic layer
  • the ceramic layer is attached to a surface of the porous polymer layer, and the other surface of the ceramic layer and the porous polymer layer are sequentially attached with a hydrophilic retardation layer and a porous polarity.
  • the polymer bonding layer ie, the polymer separator has the following structure: porous polar polymer bonding layer
  • porous polar polymerization Material bonding layer porous polar polymerization Material bonding layer
  • the polymer membrane according to the present disclosure may have a total thickness of conventionally selected, and may generally be 5 to 50 ⁇ m, such as 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, 45 ⁇ m or 50 ⁇ m.
  • the total thickness of the polymeric membrane may range from 8 to 30 [mu]m. In still other embodiments, the total thickness of the polymeric membrane may range from 10 to 20 [mu]m.
  • the polymer separator according to the present disclosure has a high gas permeability.
  • the polymer membrane according to the present disclosure has a Gurley value of 100-900 Sec/100 mL, such as 100 Sec/100 mL, 150 Sec/100 mL, 200 Sec/100 mL, 250 Sec/100 mL, 300 Sec/100 mL, 350 Sec/100 mL, 400 Sec/100 mL, 450 Sec.
  • the polymer membrane may have a Gurley value of 120-600 Sec/100 mL. In other embodiments, the polymer membrane may have a Gurley value of 120-500 Sec/100 mL. In still other embodiments, the polymer membrane may have a Gurley value of 150-350 Sec/100 mL, such as 200-300 Sec/100 mL.
  • the Gurley value can be used to characterize the gas permeability. It refers to the time required for a certain amount of air to pass through a specific area of the membrane under a specific pressure, which is related to the porosity, pore size, thickness and the tortuosity of the pore. It is a measure of the permeability of a diaphragm.
  • the hydrophilic retardation layer in the polymer separator according to the present disclosure is more hydrophilic and effective than the ceramic layer in the prior polymer separator for improving the thermal stability of the separator and the adsorption capacity of the electrolyte.
  • the polar polymer enters the porous substrate during the grounding process.
  • the pores in the porous polar polymer tie layer have a larger pore size in the polymer separator according to the present disclosure than the existing polymer separator (the porous polymer bond layer of the existing polymer separator)
  • the pore diameter is usually from 0.5 to 1 ⁇ m, and the pore diameter in the porous polar polymer bonding layer of the polymer separator according to the present disclosure may be 3 ⁇ m or more, usually 3 to 10 ⁇ m, such as 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m.
  • the porous polar polymer bonding layer is a multilayer wire mesh interlaced structure, and a part of the surface of the hydrophilic retardation layer is exposed through the multilayer wire mesh interlacing structure; however, the existing The porous polar polymeric tie layer in the polymeric separator is more dense and honeycomb-like.
  • the present disclosure provides a method of preparing a polymer separator, the method comprising: forming a hydrophilicity on one surface or opposite surfaces of a porous substrate using a hydrophilic retardation slurry a retardation layer; forming a porous polar polymer bonding layer on the surface of the hydrophilic retardation layer away from the porous substrate by using a polar polymer binder solution, the hydrophilic retardation slurry a hydrophilic inorganic particle containing a dispersion medium containing an organic solvent and a polar polymer dispersed in the organic solvent, and a binder dispersed in the dispersion medium ( Or polar polymer binder) and pore former.
  • the method is simple, convenient, easy to implement and industrialized, and the polar polymer solution does not penetrate into the pores of the porous substrate during the preparation process, ensuring a low bulk impedance and high ion conductance of the polymer membrane.
  • the polymer separator obtained by the method is used for a lithium ion battery, the performance of the lithium ion battery is not deteriorated or otherwise adversely affected.
  • the method can be used to prepare a polymeric membrane of the first aspect of the present disclosure.
  • the method specifically comprises: coating a hydrophilic retardation slurry on one surface or opposite surfaces of the porous substrate to form a pro a water-blocking coating layer, drying the hydrophilic retardation coating layer to form the hydrophilic retardation layer on a surface of the porous substrate; coating the polar polymer binder solution in the The hydrophilic retardation layer forms a polar polymer binder coating on the surface of the porous substrate, and the polar polymer binder coating is dried on the surface of the hydrophilic retardation layer.
  • a porous polar polymeric tie layer is formed.
  • the hydrophilic retardation coating layer is dried to form a hydrophilic retardation layer and then coated with a polar polymer binder solution, which can further improve the gas permeability and ionic conductivity of the finally prepared polymer separator, and further improve the adoption.
  • the performance of the lithium ion battery of the polymer membrane is dried to form a hydrophilic retardation layer and then coated with a polar polymer binder solution, which can further improve the gas permeability and ionic conductivity of the finally prepared polymer separator, and further improve the adoption.
  • the hydrophilic retardation coating layer may be dried to form a hydrophilic retardation layer, and then the polar polymer binder solution may be coated, or the hydrophilic barrier coating may not be applied.
  • the layer is dried, but the polar polymer binder solution is applied directly to the surface of the hydrophilic retardation coating.
  • the method specifically comprises: applying a hydrophilic retardation slurry to one surface of the porous substrate or opposite surfaces to form a hydrophilic retardation coating, and polymerizing the polarities Applying a binder solution to form a polar polymer binder coating on the surface of the hydrophilic barrier coating away from the porous substrate, the hydrophilic retardation coating and the The polar polymeric binder coating is dried to form a hydrophilic retardation layer on the surface of the porous substrate and a porous polar polymeric bonding layer on the surface of the hydrophilic retardation layer.
  • the preparation method may further comprise the step of coating the hydrophilic retardation slurry on at least one surface of the porous substrate (eg, a surface, relative The two surfaces, etc.) form a hydrophilic retardation coating, optionally drying the hydrophilic retardation coating to form a hydrophilic retardation layer; coating the polar polymeric binder solution
  • the hydrophilic retardation coating or the surface of the hydrophilic retardation layer forms a polar polymer binder coating; bonding the hydrophilic retardation coating to the polar polymer
  • the coating is dried to form a hydrophilic retardation layer and a porous polar polymeric tie layer, or the polar polymeric binder coating is dried to form a porous polar polymeric tie layer.
  • the porous substrate may be a porous polymer film or a composite film of a porous polymer film and a ceramic film.
  • the porous polymer film may be a porous polyolefin film.
  • the porous polymer film may be a porous polyethylene film, a porous polypropylene film, a porous polyethylene, and a porous polypropylene composite film.
  • the porous polyethylene and porous polypropylene composite film may be a PE/PP/PE composite film.
  • the ceramic in the ceramic film may be selected from the group consisting of Al 2 O 3 , SiO 2 , SnO 2 , ZrO 2 , TiO 2 , SiC, Si 3 N 4 , CaO, MgO, ZnO, BaTiO 3 , LiAlO 2 and BaSO 4 .
  • the ceramic particles formed by sintering one or more of the ceramic particles, that is, the ceramic particles in the ceramic film may be selected from the group consisting of Al 2 O 3 particles, SiO 2 particles, SnO 2 particles, ZrO 2 particles, TiO 2 particles, SiC.
  • the porous polymer film may have a thickness of 1 to 50 ⁇ m, such as 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, 3.5 ⁇ m, 4 ⁇ m, 4.5 ⁇ m, 5 ⁇ m, 5.5 ⁇ m, 6 ⁇ m, 6.5 ⁇ m.
  • the ceramic film may have a thickness of 5-20 ⁇ m. In other embodiments, the ceramic film may have a thickness of 8-15 ⁇ m. In still other embodiments, the ceramic film may have a thickness of 1-5 ⁇ m. In some embodiments, the ceramic film may have a thickness of 1.5-3 ⁇ m.
  • the hydrophilic retardation slurry may contain a dispersion medium, and hydrophilic inorganic particles dispersed in the dispersion medium, and a binder.
  • the hydrophilic inorganic particles may have a particle diameter of 1 nm to 10 ⁇ m, such as 1 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m.
  • the hydrophilic inorganic particles may have a particle diameter of from 1 nm to 5 ⁇ m. From the viewpoint of further improving the gas permeability and ionic conductivity of the finally prepared polymer separator, and the performance of the lithium ion battery using the polymer separator, in some embodiments, the hydrophilic inorganic particles may have a particle diameter of 1 nm. To 2 ⁇ m, in other specific embodiments, the hydrophilic inorganic particles have a particle diameter of 10 nm to 1 ⁇ m. In other specific embodiments, the hydrophilic inorganic particles have a particle diameter of 20 nm to 800 nm, and some specific In an embodiment, the hydrophilic inorganic particles have a particle diameter of 50 nm to 350 nm.
  • the hydrophilic inorganic particles may have a specific surface area of 10 to 600 m 2 /g, such as 10 m 2 /g, 50 m 2 /g, 100 m 2 /g, 150 m 2 /g , 200m 2 / g, 250m 2 / g, 300m 2 / g, 350m 2 / g, 400m 2 / g, 450m 2 / g, 500m 2 / g, 550m 2 / g or 600m 2 / g.
  • 10 to 600 m 2 /g such as 10 m 2 /g, 50 m 2 /g, 100 m 2 /g, 150 m 2 /g , 200m 2 / g, 250m 2 / g, 300m 2 / g, 350m 2 / g, 400m 2 / g, 450m 2 / g, 500m 2 / g, 550m 2 / g or 600m 2 / g
  • the hydrophilic inorganic particles may have a specific surface area of 100 to 500 m 2 /g from the viewpoint of further improving the gas permeability and ionic conductivity of the finally prepared polymer separator and the performance of the lithium ion battery using the polymer separator.
  • the hydrophilic inorganic particles have a specific surface area of from 150 to 400 m 2 /g. In other embodiments, the hydrophilic inorganic particles have a specific surface area of from 200 to 400 m 2 /g.
  • the hydrophilic inorganic particles have a specific surface area of from 250 to 390 m 2 /g, and in some embodiments, the hydrophilic inorganic particles have a specific surface area of from 300 to 380 m 2 /g.
  • the specific surface area is determined by a method for determining a specific surface area of a solid substance by a gas adsorption BET method of GB/T19587-2004.
  • hydrophilic inorganic particles may include, but are not limited to, hydrophilic Al 2 O 3 particles, hydrophilic SiO 2 particles, hydrophilic SnO 2 particles, pro Aqueous ZrO 2 particles, hydrophilic TiO 2 particles, hydrophilic SiC particles, hydrophilic Si 3 N 4 particles, hydrophilic CaO particles, hydrophilic MgO particles, hydrophilic ZnO particles, hydrophilic BaTiO 3 particles, the hydrophilic particles LiAlO 2, BaSO 4 particles and a hydrophilic one or two or more kinds.
  • the hydrophilic inorganic particles are one or both of hydrophilic Al 2 O 3 particles and hydrophilic SiO 2 particles.
  • the hydrophilic inorganic particles are one or both of gas phase hydrophilic SiO 2 particles, precipitation hydrophilic SiO 2 particles, and gas phase hydrophilic Al 2 O 3 particles. the above.
  • the binder in the hydrophilic retardation slurry, may be an acrylate type polymer, a styrene-acrylate copolymer, a polyvinylidene fluoride, a vinylidene fluoride.
  • a hexafluoropropylene copolymer One or more of a hexafluoropropylene copolymer, an acrylonitrile-acrylate copolymer, a vinyl chloride-acrylate copolymer, and a butadiene-styrene copolymer.
  • the dispersion medium in the hydrophilic retardation slurry, can be selected according to the kind of the hydrophilic inorganic particles and the binder to enable the hydrophilic inorganic particles and the binder
  • the agent forms a uniform and stable slurry.
  • Specific examples of the dispersion medium may include, but are not limited to, one or more of water, ethanol, isopropanol, cyclohexane, tetrahydrofuran, dichloromethane, and chloroform.
  • the content of the hydrophilic inorganic particles in the hydrophilic retardation slurry may be 50 to 95% by weight, preferably 70 to 95% by weight, such as 50% by weight, 55. % by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight or 95% by weight.
  • the hydrophilic inorganic particles may be included in an amount of 80 to 95% by weight. In other specific embodiments, the hydrophilic inorganic particles may be included in an amount of 85 to 95% by weight.
  • the amount of the binder can be selected in accordance with the amount of the hydrophilic inorganic particles to bind and fix the hydrophilic inorganic particles.
  • the binder may be included in an amount of 1 to 30 parts by weight, such as 1 part by weight, 2 parts by weight, or 3 parts by weight relative to 100 parts by weight of the hydrophilic inorganic particles.
  • the binder may be included in an amount of 2 to 25 parts by weight based on 100 parts by weight of the hydrophilic inorganic particles, and in other specific examples, relative to 100 parts by weight of the hydrophilic inorganic particles.
  • the binder may be included in an amount of 5 to 20 parts by weight.
  • the hydrophilic retardation slurry may further contain a dispersing agent to further improve the stability of the hydrophilic retardation slurry.
  • the dispersing agent may be a common substance which can promote the dispersibility of the inorganic particles in a liquid medium, and specific examples thereof may include, but are not limited to, one or two of polyvinyl alcohol (PVA) and sodium polyacrylate (PAANa). .
  • PVA polyvinyl alcohol
  • PAANa sodium polyacrylate
  • the amount of the dispersant may be a conventional choice.
  • the dispersant may be used in an amount of 0.1 to 10 parts by weight, such as 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6, based on 100 parts by weight of the hydrophilic inorganic particles. Parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight Or 10 parts by weight.
  • the dispersant may be used in an amount of 0.2 to 5 parts by weight relative to 100 parts by weight of the hydrophilic inorganic particles, and in other specific examples, relative to 100 parts by weight of the hydrophilic inorganic particles.
  • the dispersant may be used in an amount of from 0.3 to 2 parts by weight.
  • the hydrophilic retardation slurry may further contain a thickener to further improve the coatability of the hydrophilic barrier slurry.
  • the thickener may be one or both of a cellulose type thickener and a polyacrylate type alkali swellable thickener such as BASF Latekoll D thickener.
  • the thickener may be used in an amount of 0.1 to 10 parts by weight, such as 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, per 100 parts by weight of the hydrophilic inorganic particles.
  • the thickener may be used in an amount of 0.5 to 5 parts by weight relative to 100 parts by weight of the hydrophilic inorganic particles, and in other embodiments, relative to 100 parts by weight of the hydrophilic inorganic particles.
  • the thickener may be used in an amount of from 0.8 to 2 parts by weight.
  • the pH of the hydrophilic retardation slurry can be adjusted to be alkaline.
  • the pH of the hydrophilic retardation slurry can be 8-10. Such as 8, 8.5, 9, 9.5 or 10.
  • the hydrophilic retardation slurry preferably has a solid content of 2 to 30% by weight, such as 2% by weight, 5% by weight, 10% by weight, 15% by weight, and 20% by weight. 25% by weight, 30% by weight.
  • the hydrophilic barrier slurry may have a solids content of from 5 to 25% by weight.
  • the coating amount of the hydrophilic barrier slurry on the surface of the porous substrate can be selected according to the thickness of the desired hydrophilic retardation layer.
  • the hydrophilic retardation slurry is applied in an amount such that the hydrophilic retardation layer has a thickness of 0.1 to 3 ⁇ m, for example, 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, and 0.6 ⁇ m.
  • the hydrophilic retardation slurry is applied in an amount such that the hydrophilic retardation layer has a thickness of 0.1 to 1 ⁇ m.
  • the hydrophilic barrier slurry is The coating amount is such that the hydrophilic retardation layer has a thickness of 0.3 to 0.8 ⁇ m.
  • the hydrophilic retardation coating may be dried at a temperature of 10 to 120 ° C, such as 10 ° C, 20 ° C, 30 ° C, 40 ° C, 50 ° C, 60 ° C, 70 ° C. , 80 ° C, 90 ° C, 100 ° C, 110 ° C, 120 ° C.
  • the temperature at which the hydrophilic barrier coating is dried is not higher than 100 °C.
  • the drying temperature is not higher than 80 ° C, for example, 10-80 ° C, specifically 10 ° C, 15 ° C, 20 ° C, 25 ° C, 30 ° C, 35 ° C, 40 ° C, 45 °C, 50 ° C, 55 ° C, 60 ° C, 65 ° C, 70 ° C, 75 ° C, or 80 ° C.
  • the drying temperature is 40-60 ° C, such as 50-60 ° C. Drying the hydrophilic barrier coating can be carried out under normal pressure or under reduced pressure. In still other embodiments, drying the hydrophilic barrier coating can be carried out under normal pressure. In some embodiments, drying the hydrophilic barrier coating can be carried out in a forced air drying oven.
  • the duration in which the hydrophilic barrier coating is dried can be selected depending on the drying temperature and the type of dispersant employed. Generally, the duration of drying of the hydrophilic barrier coating can range from 0.1 to 24 hours, such as 0.1 hours, 1 hour, 3 hours, 5 hours, 10 hours, 15 hours, 20 hours, or 24 hours. In some embodiments, the hydrophilic barrier coating may be dried for a duration of 5-18 hours. In other embodiments, the hydrophilic barrier coating may be dried for a duration of 8-15 hours. .
  • the contact angle of the hydrophilic retardation layer with water may be 40° or less, for example, 1°, 2°, 3°, 4°, 5°, 6°, 7 °, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 °.
  • the hydrophilic retardation layer has a contact angle with water of 20° or less.
  • the hydrophilic retardation layer obtained above has a contact angle with water of 2-18°, specifically 5-15°. The contact angle is determined by the method specified in GB/T 30693-2014 plastic film and water contact angle measurement.
  • the polar polymer binder solution contains an organic solvent and a polar polymer binder and a pore former dispersed in the organic solvent.
  • the polar polymer binder may be one of a polyvinylidene fluoride, a vinylidene fluoride-hexafluoropropylene copolymer, and a vinylidene fluoride-acrylate copolymer. Or two or more.
  • the organic solvent may be a low boiling organic solvent (an organic solvent having a boiling point lower than 60 ° C), such as acetone; or a high boiling solvent such as a solvent having a boiling point of 60 ° C or higher. It may also be a mixture of a low boiling solvent and a high boiling solvent.
  • the content of the low boiling point solvent can be controlled to be no higher than the safety threshold at which the explosion occurs, from the viewpoint of further improving the operational safety.
  • the organic solvent is a low boiling point solvent, specifically acetone.
  • the lithium ion battery prepared by using the polymer separator exhibits markedly improved large-rate discharge performance and high-temperature performance.
  • the hydrophilic inorganic particles may have a particle diameter of 1 nm to 2 ⁇ m, 10 nm to 1 ⁇ m, 20 nm to 800 nm, or 50 nm to 350 nm, and the contact angle of the hydrophilic retardation layer with water may be 20° or less, and The polar polymer binder coating is dried at a temperature not higher than 60 °C.
  • the organic solvent is a high boiling solvent, such as an organic solvent having a boiling point of 60 ° C or higher (eg, 60-260 ° C). In some embodiments, the organic solvent is organic having a boiling point of 120 ° C or higher. Solvent (e.g., 120-260 ° C). In other embodiments, the organic solvent is an organic solvent having a boiling point of 140 ° C or higher (e.g., 140-260 ° C). In still other embodiments, the organic solvent has a boiling point of 145-260 ° C, such as 150-230 ° C.
  • organic solvent may include, but are not limited to, triethyl phosphate, N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide. One or two or more. According to this embodiment, operational safety can be improved.
  • the organic solvent is a mixture of a low boiling solvent and a high boiling solvent.
  • the low boiling point solvent and the high boiling point solvent are each the same as described above.
  • the content of the high boiling point solvent may be 0.1 to 99.9% by weight, specifically 20 to 90% by weight, more specifically 40 to 70% by weight, based on the total amount of the organic solvent, and further may be
  • the content of the low boiling point solvent may be from 0.1 to 99.9% by weight, specifically from 10 to 80% by weight, more specifically from 30 to 60% by weight, and further may from 45 to 55% by weight.
  • the pore former is simultaneously dried or coated with the hydrophilic retardation coating layer and the polar polymer binder coating layer A polymeric binder coating that forms a volatile gas when dried.
  • the pore former may be a substance which is solid at the coating temperature and which forms a volatile gas under the above drying conditions.
  • the pore former may specifically be dry ice.
  • the polar polymer binder solution may have a weight ratio of the pore former of 0.5 to 5 parts by weight, specifically 0.5, with respect to 100 parts by weight of the organic solvent. Parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, etc., in some embodiments, relative to 100 parts by weight
  • the weight ratio of the pore former may be 0.8 to 3 parts by weight, and in other specific examples, the weight ratio of the pore former may be 1-2 parts by weight relative to 100 parts by weight of the organic solvent. .
  • the polar polymer binder solution has a concentration of the polar polymer binder of 1 to 30% by weight, such as 2% by weight, 5% by weight, 10% by weight 15% by weight, 20% by weight, 25% by weight, and 30% by weight.
  • the concentration of polar polymer in the polar polymeric binder solution is from 2 to 25% by weight.
  • the concentration of the polar polymer binder in the polar polymer binder solution may be 5- 20% by weight.
  • the concentration of the polar polymeric binder in the polar polymeric binder solution is a critical concentration (typically from 8 to 15% by weight, specifically from 10 to 12% by weight).
  • the critical concentration refers to the concentration of the polar polymer binder solution passing through the porous substrate, and the polar polymer can be bonded in an environment of 25 ° C, 1 standard atmospheric pressure and a relative humidity of RH 45% to 55%.
  • the solution is coated on one surface of the porous substrate, and it is observed whether the polar polymer binder solution permeates the porous substrate within 1 hour, and is at a concentration that is transmitted through the porous substrate and a concentration that does not penetrate the porous substrate. The concentration between them is taken as the critical concentration.
  • the concentration of the polar polymer binder is a critical concentration
  • the polar polymer binder is in a solution, which is microscopically gel-like, and the single molecule is difficult to flow and diffuse, which can strengthen the polar polymer molecules.
  • the interaction between the two forms an ideal physical cross-linking network structure during solvent evaporation, so that the polymer separator has more excellent gas permeability and ionic conductivity.
  • the lithium ion battery using the polymer separator has superior performance. performance.
  • the coating amount of the polar polymer binder solution can be selected according to the thickness of the desired polar polymer bonding layer.
  • the coating amount of the polar polymer binder solution may be such that the thickness of the finally formed porous polar polymer bonding layer is 0.1 to 10 ⁇ m, such as 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1.0 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m.
  • the polar polymer binder solution may be applied in an amount such that the finally formed porous polar polymer tie layer may have a thickness of 0.2 to 5 ⁇ m.
  • the polar polymer The coating amount of the binder solution may be such that the thickness of the finally formed porous polar polymer bonding layer may be 0.7 to 3 ⁇ m, and in some embodiments, the coating amount of the polar polymer binder solution may be made.
  • the finally formed porous polar polymer bonding layer may have a thickness of 0.8 to 1.5 ⁇ m.
  • drying the polar polymer binder coating can be carried out at a temperature not higher than 120 °C.
  • drying the polar polymeric binder coating can be carried out at a temperature not higher than 60 ° C, and can be 10-60 ° C, for example: 10 ° C, 15 ° C, 20 ° C, 25 ° C, 30 ° C, 35 ° C, 40 ° C, 45 ° C, 50 ° C, 55 ° C, or 60 ° C.
  • the polar polymeric binder coating is dried at a temperature of from 20 to 55 °C. In still other embodiments, the polar polymeric binder coating is dried at a temperature of from 30 to 45 °C. The duration of drying the polar polymeric binder coating can be selected based on the drying temperature.
  • the duration of drying the polar polymeric binder coating may be from 0.1 to 36 hours, specifically, such as 0.1 hours, 1 hour, 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 36 hours and so on. In some embodiments, the duration of drying the polar polymeric binder coating can be from 5 to 30 hours. In other embodiments, the duration of drying the polar polymeric binder coating can be 8-24 hours, and in some specific examples, 10-24 hours.
  • the above-mentioned coated hydrophilic retardation slurry and polar polymer binder solution may be subjected to a conventional coating method such as roll coating, spray coating, immersion coating, and silk.
  • a conventional coating method such as roll coating, spray coating, immersion coating, and silk.
  • a hydrophilic retardation layer and a porous polar polymer bonding layer may be formed on one side of the porous substrate, or a hydrophilic layer may be formed on both sides of the porous substrate.
  • a barrier layer and a porous polar polymeric tie layer may be formed on one side of the porous substrate, or a hydrophilic layer may be formed on both sides of the porous substrate.
  • the finally prepared polymer membrane is composed of a porous substrate, a hydrophilic retardation layer, and a porous polar polymer tie layer, the porous substrate being a porous polymer a film, the hydrophilic retardation layer is attached to a surface of the porous substrate, and the porous polar polymer bonding layer is attached to a surface of the hydrophilic retardation layer.
  • the hydrophilic retardation layer and the porous polar polymer bonding layer may be sequentially disposed on one surface of the porous substrate (that is, the polymer separator has the following structure: porous polymer film
  • the finally prepared polymer membrane is composed of a porous substrate, a hydrophilic retardation layer, and a porous polar polymer bonding layer, which is a porous polymerization.
  • a composite film of a film and a ceramic film is attached to the surface of the porous polymer film, and the hydrophilic retardation layer is attached to the surface of the ceramic film, the porous polar polymer The bonding layer is attached to the surface of the hydrophilic retardation layer (that is, the polymer separator has the following structure: porous polymer film
  • the porous polymer film is attached to a surface of the ceramic layer, the hydrophilic retardation layer is attached to a surface of the porous polymer film, and the porous polar polymer is bonded
  • the layer is attached to the surface of the hydrophilic retardation layer (that is, the polymer membrane has the following structure: ceramic membrane
  • the ceramic film is attached to the surface of the porous polymer film, and the other surface of the ceramic film and the porous polymer film are sequentially bonded to the hydrophilic retardation layer and the porous polar polymer.
  • the layer ie, the polymer separator has the following structure: porous polar polymer bonding layer
  • the present disclosure provides a polymer membrane prepared by the method of the second aspect of the present disclosure.
  • the polymer membrane is provided with a hydrophilic retardation layer such that the polar polymer binder solution does not penetrate into the pores of the porous substrate when preparing the porous polar polymer binder layer, and the polymer membrane has a lower
  • the bulk impedance and high ionic conductivity do not cause a decrease in the performance of the lithium ion battery using the polymer separator, and the polar polymer binder solution can use a higher boiling organic solvent, which can significantly improve the operation safety. Sex.
  • the polymer separator prepared by the method of the second aspect of the present disclosure may have a total thickness of 5 to 50 ⁇ m, such as 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m. 35 ⁇ m, 40 ⁇ m, 45 ⁇ m or 50 ⁇ m.
  • the total thickness of the polymeric membrane may range from 8 to 30 microns. In other embodiments, the total thickness of the polymeric membrane may range from 10 to 20 microns.
  • the polymer separator prepared by the method of the second aspect of the present disclosure has high gas permeability.
  • the polymer membrane prepared by the method of the second aspect of the present disclosure has a Gurley value of 100-900 Sec/100 mL, such as 100 Sec/100 mL, 150 Sec/100 mL, 200 Sec/100 mL, 250 Sec/100 mL, 300 Sec/100 mL, 350 Sec/ 100 mL, 400 Sec/100 mL, 450 Sec/100 mL, 500 Sec/100 mL, 550 Sec/100 mL, 600 Sec/100 mL, 650 Sec/100 mL, 700 Sec/100 mL, 750 Sec/100 mL, 800 Sec/100 mL, 850 Sec/100 mL or 900 Sec/100 mL.
  • the polymer membrane may have a Gurley value of 120-600 Sec/100 mL. In other embodiments, the polymer membrane may have a Gurley value of 120-500 Sec/100 mL. In still other embodiments, the polymer membrane prepared by the method of the second aspect of the present disclosure has a Gurley value of 150-350 Sec/100 mL, specifically 200-300 Sec/100 mL.
  • the hydrophilic retardation layer in the polymer membrane prepared by the method of the second aspect of the present disclosure is compared with the ceramic layer in the prior polymer membrane for improving the thermal stability of the membrane and the adsorption capacity of the electrolyte. It is more water-based and can effectively block the polar polymer from entering the porous substrate during the preparation process.
  • the polymer separator prepared by the method of the second aspect of the present disclosure has a larger pore diameter in the porous polar polymer bonding layer (the porous pore of the existing polymer separator)
  • the pore diameter in the polymer polymer bonding layer is usually from 0.5 ⁇ m to 1 ⁇ m, and the pore diameter in the porous polar polymer bonding layer of the polymer separator according to the present disclosure is 3 ⁇ m or more, usually 3 to 10 ⁇ m, such as 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m)
  • the porous polar polymer bonding layer is a multilayer wire mesh interlaced structure, and a part of the surface of the hydrophilic retardation layer passes through the multilayer wire mesh interlaced structure The exposure is visible; however, the porous polar polymeric tie layer in the existing polymeric separator is more dense and honeycomb-like.
  • the present disclosure provides the use of the polymer separator of the first or third aspect of the present disclosure in a lithium ion battery.
  • the polymer film is used for a lithium ion battery, and can be firmly bonded to the positive electrode tab and the negative electrode tab of the lithium ion battery, and has strong binding force with the positive electrode tab and the negative electrode tab, so that the lithium ion battery has a comparative advantage.
  • the high hardness does not cause the battery performance to be weakened or other adverse effects on the battery.
  • the lithium ion battery has better electrical performance and better safety.
  • the present disclosure provides a lithium ion battery including a positive electrode tab, a negative electrode tab, and a polymer separator, wherein the polymer separator is the first aspect of the disclosure Or the polymeric separator of the third aspect.
  • the polymer separator in the lithium ion battery can be firmly combined with the positive electrode tab and the negative electrode tab, has high hardness, better electrical performance and good safety.
  • the positive electrode tab is made by coating a positive electrode material for a lithium ion battery, a conductive agent, and a binder onto an aluminum foil.
  • the positive electrode material used includes any positive electrode material usable for a lithium ion battery, for example, lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), lithium manganese oxide (LiMn 2 O 4 ), and lithium iron phosphate (LiFePO 4 ).
  • the negative electrode tab is made by coating a negative electrode material for a lithium ion battery, a conductive agent, and a binder onto a copper foil.
  • the negative electrode material used includes any negative electrode material usable for a lithium ion battery, for example, one or more of graphite, soft carbon, and hard carbon.
  • the lithium ion battery according to the present disclosure may or may not contain an electrolytic solution.
  • the electrolyte is well known to those skilled in the art and contains a lithium salt and an organic solvent.
  • the lithium salt may be a dissociable lithium salt, and may be, for example, one or more selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), and lithium tetrafluoroborate (LiBF 4 ).
  • the organic solvent may be selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) and vinylene carbonate.
  • VC ethylene carbonate
  • the concentration of the lithium salt in the electrolyte may be from 0.8 to 1.5 mol/L.
  • a lithium ion battery according to the present disclosure may be prepared by a method comprising the following steps:
  • the polymer separator is disposed between the positive electrode tab and the negative electrode tab to form a battery pole core, and then packaged.
  • Step S2 can be carried out by a conventional method in the technical field of lithium ion battery preparation, which is not particularly limited in the present disclosure.
  • the electrolyte may be filled into the battery core, or may be directly packaged without filling the electrolyte.
  • the contact angle of the hydrophilic retardation layer and water is determined by the method specified in GB/T30693-2014 Plastic film and water contact angle measurement.
  • the particle size is measured by a laser particle size analyzer and is a volume average particle diameter.
  • Examples 1-1 to 1-4 were used to prepare a hydrophilic retardation layer according to the present disclosure.
  • Hydrophilic silica (specific surface area 380 m 2 /g, particle size 80 nm, purchased from Aladdin) and acrylate adhesive (P1005, purchased from Shanghai Aigao Chemical Co., Ltd.) prepared by gas phase method , dispersant (PVA, purchased from Aladdin), dispersant (PAANa, purchased from Showa Denko, Japan), carboxymethyl cellulose (CMC, purchased from Daicel, Japan) as a thickener at a solid content of 95:5: 0.4:0.4:1.5 (weight ratio) was dispersed in water, the solid content was controlled to be 8% by weight, the pH of the slurry was adjusted to 8.5, and the mixture was uniformly stirred to form a hydrophilic retardation slurry.
  • PVA dispersant
  • PAANa dispersant
  • CMC carboxymethyl cellulose
  • the hydrophilic retardation slurry was applied by a gravure roll coating to a single-sided ceramic separator (9 ⁇ m PE + 2 ⁇ m ceramic layer, and the ceramic particles in the ceramic layer were micron-sized alumina ceramic particles, purchased from Shandong Guozhu , the same under both sides, drying at 55 ° C for 12 hours, to obtain a membrane with a hydrophilic retardation layer, wherein the hydrophilic retardation layer has a thickness of 0.5 ⁇ m, the contact angle of the hydrophilic retardation layer and water It is 7°.
  • Figures 1 and 2 show SEM topographical images of the hydrophilic retardation layer.
  • Hydrophilic silica prepared by precipitation method (specific surface area: 370 m 2 /g, particle size 150 nm, purchased from Aladdin), acrylate adhesive (P1005, purchased from Shanghai Aigao Chemical Co., Ltd.) , dispersant (PVA), dispersant (PAANa), thickener Latekoll D (purchased from BASF) dispersed in water at a solid content of 95:8:0.4:0.4:1.0 (weight ratio), controlling the solid content of the slurry to 6 The weight % was adjusted to adjust the pH of the slurry to 9.6, and the mixture was uniformly stirred to form a hydrophilic retardation slurry.
  • PVA dispersant
  • PAANa dispersant
  • thickener Latekoll D purchased from BASF
  • the hydrophilic retardation slurry was applied to both sides of the single-sided ceramic separator by a gravure roll coating method, and dried at 50 ° C for 14 hours to obtain a separator having a hydrophilic retardation layer, wherein the hydrophilic retardation was carried out.
  • the thickness of the layer was 0.7 ⁇ m, and the contact angle of the hydrophilic retardation layer and water was 11°.
  • Hydrophilic alumina prepared surface area 350 m 2 /g, particle size 200 nm, purchased from Aladdin), acrylate adhesive (P2010, purchased from Shanghai Aigao Chemical Co., Ltd.) ), dispersant (PVA), dispersant (PAANa), thickener Latekoll D (purchased from BASF) dispersed in water at a solids content of 95:10:0.4:0.4:1.4 (weight ratio) to control the solids content of the slurry 22% by weight, the pH of the slurry was adjusted to 8.2, and the mixture was stirred uniformly to form a hydrophilic retardation slurry.
  • PVA dispersant
  • PAANa dispersant
  • thickener Latekoll D purchased from BASF
  • the hydrophilic retardation slurry was applied to both sides of the single-sided ceramic separator by spraying, and dried at 50 ° C for 8 hours to obtain a separator having a hydrophilic retardation layer, wherein the thickness of the hydrophilic retardation layer At 0.6 ⁇ m, the contact angle of the hydrophilic barrier layer and water was 13°.
  • Hydrophilic alumina prepared surface area 320 m 2 /g, particle size 320 nm, purchased from Aladdin), acrylate adhesive (P2010, purchased from Shanghai Aigao Chemical Co., Ltd.) ), dispersant (PVA), dispersant (PAANa), thickener Latekoll D (purchased from BASF) dispersed in water at a solid content of 95:12:0.4:0.4:0.8 (weight ratio) to control the solid content of the slurry 15% by weight, the pH of the slurry was adjusted to 9.5, and the mixture was uniformly stirred to form a hydrophilic retardation slurry.
  • the hydrophilic retardation slurry was applied to both sides of the single-sided ceramic separator by a gravure roll coating method, and dried at 50 ° C for 12 hours to obtain a separator having a hydrophilic retardation layer, wherein the hydrophilic retardation was carried out.
  • the thickness of the layer was 0.8 ⁇ m, and the contact angle of the hydrophilic retardation layer and water was 12°.
  • P(VDF-HFP) powder (Kynar powerflex LBG powder, purchased from Arkema, the same below) was dissolved in N,N-dimethylformamide to control the concentration of P(VDF-HFP) as a critical The concentration (10% by weight) was stirred well. The temperature of the solution formed by stirring was lowered to 20 ° C, and dry ice was added to obtain a polar polymer binder solution in which dry ice was added in an amount of 1 part by weight based on 100 parts by weight of N,N-dimethylformamide. .
  • the polar polymer binder solution was applied by gravure roll coating to the surface of the hydrophilic retardation layer on both sides of the separator having the hydrophilic retardation layer prepared in Example 1-1 at 45 ° C
  • the air was dried for 10 hours to form a porous polar polymer tie layer, thereby obtaining a polymer separator according to the present disclosure.
  • LiCoO 2 , PVDF binder and carbon black were slurried in a mass ratio of 100:0.8:0.5, coated on an aluminum foil, and dried to form a LiCoO 2 positive electrode sheet having a thickness of 0.114 mm.
  • Styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) were dispersed in water, and stirred at a high speed of 2.5:1.5:90:6 at room temperature (25 ° C) for 3.5 hours with artificial graphite and conductive agent.
  • a good material is applied to the copper foil and dried to form a graphite negative pole piece having a thickness of 0.135 mm.
  • the LiCoO 2 positive electrode tab, the graphite negative electrode tab and the polymer separator prepared in the step (2) are prepared by winding to prepare a CSL454187 LiCoO 2 /graphite soft-packed lithium ion battery core.
  • the electrolyte is packaged to obtain a lithium ion battery; wherein the original ceramic surface faces the positive electrode, the electrolyte in the electrolyte is lithium hexafluorophosphate, the concentration is 1 mol/L, and the organic solvent is EC, EMC and DEC by weight ratio 1:1:1. Mix the resulting mixture.
  • Example 2-1B A lithium ion battery was prepared in the same manner as in Example 2-1A except that in the step (1), the polar polymer binder solution was applied by immersion coating method to the examples. a surface of a hydrophilic retardation layer on both sides of a separator having a hydrophilic retardation layer prepared by 1-3, wherein a separator having a hydrophilic retardation layer is immersed in a polar polymer binder solution, immersion time It is 30 seconds.
  • Example 2-2A A lithium ion battery was prepared in the same manner as in Example 2-1A except that a polymer separator was prepared by dissolving P(VDF-HFP) powder in N-methylpyrrolidone, and controlling The concentration of P(VDF-HFP) was a critical concentration (12% by weight) and was stirred well. The temperature of the solution formed by stirring was lowered to 20 ° C, and dry ice was added to obtain a polar polymer binder solution in which dry ice was added in an amount of 1.5 parts by weight based on 100 parts by weight of N-methylpyrrolidone.
  • the polar polymer binder solution was applied by gravure roll coating to the surface of the hydrophilic retardation layer on both sides of the separator having the hydrophilic retardation layer prepared in Example 1-2, respectively.
  • the film was dried by blasting for 24 hours to form a porous polar polymer bonding layer, thereby obtaining a polymer separator according to the present disclosure.
  • Example 2-2B A lithium ion battery was prepared in the same manner as in Example 2-2A except that in the step (1), the polar polymer binder solution was applied by immersion coating method to the examples. a surface of a hydrophilic retardation layer on both sides of a separator having a hydrophilic retardation layer prepared by 1-4, wherein a separator having a hydrophilic retardation layer is immersed in a polar polymer binder solution, immersion time It is 30 seconds.
  • Example 2-3A A lithium ion battery was prepared in the same manner as in Example 2-1A except that the polymer separator was prepared by dissolving P(VDF-HFP) powder in triethyl phosphate to control P.
  • the concentration of (VDF-HFP) was a critical concentration (12% by weight), and the mixture was uniformly stirred.
  • the temperature of the solution formed by stirring was lowered to 20 ° C, and dry ice was added to obtain a polar polymer binder solution in which dry ice was added in an amount of 1.8 parts by weight based on 100 parts by weight of triethyl phosphate.
  • the polar polymer binder solution was applied by gravure roll coating to the surface of the hydrophilic retardation layer on both sides of the separator having the hydrophilic retardation layer prepared in Example 1-2 at 30 ° C
  • the air was dried for 24 hours to form a porous polar polymer tie layer, thereby obtaining a polymer separator according to the present disclosure.
  • Example 2-3B A lithium ion battery was prepared in the same manner as in Example 2-3A except that in the step (1), the polar polymer binder solution was applied by immersion coating method to the examples. a surface of a hydrophilic retardation layer on both sides of a separator having a hydrophilic retardation layer prepared by 1-3, wherein a separator having a hydrophilic retardation layer is immersed in a polar polymer binder solution, immersion time It is 30 seconds.
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1A except that in the step (1), the separator having the hydrophilic retardation layer was the one-sided ceramic separator of Example 1-1. (9 ⁇ mPE+2 ⁇ m ceramic layer) instead, the polar polymer binder solution is directly applied to both sides of the single-sided ceramic separator, and N,N-dimethylformamide is replaced by an equal weight of acetone to obtain a polymer.
  • Membrane the polymer membrane does not have a hydrophilic retardation layer).
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-3B except that the separator having a hydrophilic retardation layer was used as the single-sided ceramic of Examples 1-3 in the preparation of the polymer separator. Instead of the separator (9 ⁇ m PE + 2 ⁇ m ceramic layer), the polar polymer binder solution was directly applied to both sides of the single-sided ceramic separator, and triethyl phosphate was replaced with an equal weight of acetone to obtain a polymer separator (the polymerization) The separator does not have a hydrophilic retardation layer).
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1A except that the polar polymer binder solution contained no dry ice.
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1A except that the separator having a hydrophilic retardation layer was used as the one-sided ceramic of Examples 1-3 in the preparation of the polymer separator. Instead of the separator (9 ⁇ m PE + 2 ⁇ m ceramic layer), the polar polymer binder solution was directly applied to both side surfaces of the single-sided ceramic separator to obtain a polymer separator (the polymer membrane did not have a hydrophilic retardation layer).
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1B except that in the step (1), the blast was not dried at 35 ° C for 20 hours, but was blown at 120 ° C for 8 hours. hour.
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1B except that the concentration of P(VDF-HFP) was controlled to be 4% by weight in the preparation of the polar polymer binder solution (non- Critical concentration).
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1B except that the concentration of P(VDF-HFP) was controlled to be 22% by weight in the preparation of the polar polymer binder solution (non- Critical concentration).
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1B except that N,N-dimethylformamide was replaced with an equal weight of acetone in the preparation of the polar polymer binder solution. .
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 2-1B, except that in the preparation of the polar polymer binder solution, N,N-dimethylformamide was used in an equal weight of acetone and Instead of the mixed solution of N,N-dimethylamide, the weight ratio of acetone to N,N-dimethylformamide was 1:1.
  • a separator having a hydrophilic retardation layer was prepared in the same manner as in Example 1-1, except that in the step (1), the vapor phase hydrophilic silica was made of quartz (having a specific surface area of 10 m 2 /g, The particle size was 10 ⁇ m instead, thereby obtaining a separator having a hydrophilic retardation layer, and the hydrophilic retardation layer was formed to have a contact angle of 38° with water; a polymer separator was prepared in the same manner as in Example 2-1A. Unlike the lithium ion battery, the separator having the hydrophilic retardation layer prepared in Example 8 was used.
  • a separator having a hydrophilic retardation layer was prepared in the same manner as in Example 1-3 except that the vapor phase hydrophilic aluminum oxide was aluminized aluminum oxide (having a specific surface area of 130 m 2 /g). Instead of the particle size of 5 ⁇ m, a separator having a hydrophilic retardation layer was obtained, and the hydrophilic retardation layer was formed to have a contact angle of 32° with water; a polymer was prepared in the same manner as in Example 2-1B. The separator and the lithium ion battery were different from the separator having the hydrophilic retardation layer prepared in Example 9.
  • Example 10 A lithium ion battery was prepared in the same manner as in Example 2-1B except that in the step (1), the polar polymer binder solution was applied by spray coating to Example 1 3 The surface of the hydrophilic retardation layer on both sides of the separator having the hydrophilic retardation layer prepared.
  • a polymer separator and a lithium ion battery were prepared in the same manner as in Example 10 except that the hydrophilic barrier slurry was applied to both sides of the single-sided ceramic separator in the same manner as in Example 10, and was not dried. Instead, the polar polymer binder solution was sprayed directly by the method of Example 10, and then dried in the same manner as in Example 10 to obtain a polymer separator.
  • microstructure of the polymer separator prepared in each of the examples and the comparative examples was observed using a scanning electron microscope (SEM, JEOL, JSM-7600FE).
  • FIGS. 3 and 4 show SEM topographical photographs of the polymer separator prepared in Example 2-1A
  • Figs. 5 and 6 show SEM topography photographs of the polymer separator prepared in Example 2-1B.
  • the porous polar polymer bonding layer having a relatively good porosity can be prepared by the method of the present disclosure, and the surface of the porous polar polymer bonding layer prepared at the same time. It has a porous membrane layer.
  • 7 and 8 show SEM topographical photographs of the polymer separator prepared in Comparative Example 1
  • Figs. 9 and 10 show SEM topographical photographs of the polymer separator prepared in Comparative Example 3.
  • the pores in the porous polar polymeric tie layer of the polymer membrane surface according to the present disclosure comprise a pore having a first pore size and having a second pore size a hole having a first pore diameter of 5-20 ⁇ m and a second pore diameter of 200 nm-2 ⁇ m, wherein a part of the surface of the hydrophilic retardation layer is exposed through the multilayered wire mesh interweaving structure; Comparative Example 1
  • the porous polar polymeric tie layer in the prepared polymer separator is relatively dense and honeycomb-like.
  • the pores in the porous polar polymeric tie layer of the polymeric membrane prepared by the method of the present disclosure comprise a pore having a first pore size and having a second The pores of the pore size, the first pore diameter is 5-20 ⁇ m, and the second pore diameter is 200 nm-2 ⁇ m.
  • the polymer separator according to the present disclosure showed better gas permeability.
  • the apparent porosity of the polymer membrane is calculated according to the following formula:
  • ⁇ M is the apparent density
  • ⁇ f is the areal density
  • ⁇ P is the bulk density
  • d is the thickness of the polymer separator.
  • the polymer membranes according to the present disclosure have a higher apparent porosity.
  • the polymer separator (area 5 mm ⁇ 5 mm) was isothermally heat treated at 90 ° C and 120 ° C for 2 h and 1 h, respectively, to characterize the temperature resistance of the polymer separator.
  • the diameter of the steel needle is 1 mm using a universal testing machine.
  • Thickness of polymer membrane 2 single-plane density of polar polymer coating on both surfaces of polymer membrane
  • the polymer diaphragm is cut into a disk having a diameter of 17 mm. After drying, it is overlapped by three layers and placed between two stainless steel (SS) electrodes to absorb a sufficient amount of electrolyte (electrolyte is lithium hexafluorophosphate, the concentration is 1 mol/L, organic
  • the solvent is a mixture of EC, EMC and DEC at a weight ratio of 1:1:1. It is sealed in a 2016 type button cell.
  • the electrochemical impedance workstation (Shanghai Chenhua, CHI 660C) is used for AC impedance test and AC signal. The frequency range is from 0.01 Hz to 1 MHz, and the sinusoidal potential amplitude is 5 mV.
  • the intersection of the linear and real axes is the bulk resistance of the polymer membrane.
  • the ionic conductivity of the polymer membrane is calculated by the following formula:
  • A is the contact area between the stainless steel plate and the polymer separator.
  • R is the bulk impedance of the polymer electrolyte.
  • the polymer separator according to the present disclosure exhibits excellent ionic conductivity.
  • the prepared lithium ion battery (after 85 ° C, 4 h, 1 MPa hot pressing) was dissected in a fully charged state, and the mechanical strength of the peeling was measured by a universal testing machine.
  • the test standard was tested with reference to the peel strength of the adhesive tape of GBT 2792-2014. Method; and taking the obtained positive and negative pole pieces and the separator to take a picture.
  • 11 and FIG. 12 and FIG. 13 and FIG. 14 respectively show SEM topographic photographs of the positive electrode and the negative electrode of the lithium ion battery prepared in Example 2-1A after peeling off from the polymer separator
  • FIG. 15 and FIG. 17 respectively show The peel strength test curves of the positive electrode and the negative electrode of the lithium ion battery prepared in Example 2-1A
  • FIG. 16 and FIG. 18 respectively show the peel strength test curves of the positive electrode and the negative electrode of the lithium ion battery prepared in Comparative Example 1 as a comparison .
  • the polymer separator according to the present disclosure has a high viscosity to both the positive electrode and the negative electrode of the lithium ion battery.
  • the test results are listed in Table 3. As shown in Table 3, the lithium ion battery according to the present disclosure has a higher hardness.
  • the 25 °C cycle performance test was carried out on the lithium ion battery after the separation of the sample and the comparative examples prepared by using the (Guangzhou Lanqi, BK6016) lithium ion battery performance test cabinet.
  • the specific method is as follows.
  • the batteries were charged to 0.70 V cutoff at 0.7 C, 0.2 C, respectively; left for 10 min, put at 3.0 C or 0.2 C to 3.0 V, and cycled.
  • the test results of Table 4 indicate that the lithium ion battery according to the present disclosure exhibits more excellent cycle performance.
  • the lithium ion battery performance test cabinet (Guangzhou Lanqi, BK6016) was used to test the cycle performance of the 45 °C lithium ion battery obtained in the examples and the comparative examples.
  • the test method is: charging the battery to 0.70 V cutoff at 0.7 C; leaving it for 10 min, putting it at 0.7 C to 3.0 V, and circulating.
  • the cycle results are shown in Table 5.
  • the test results show that the lithium ion battery according to the present disclosure exhibits more excellent high temperature cycle performance. It can thus be seen that the polymer membrane according to the present disclosure is advantageous for improving the high temperature performance of the battery.
  • the lithium ion battery performance test cabinet (Guangzhou Lanqi, BK6016) was used to conduct the rate discharge performance test on the Lithium ion batteries obtained in the examples and the comparative examples.
  • the specific test method is as follows.
  • the rate discharge test results are shown in Table 6.
  • the test results show that the lithium ion battery according to the present disclosure shows good rate discharge performance.
  • the lithium ion batteries obtained in the examples and the comparative examples were subjected to a storage performance test at 85 ° C for 4 hours.
  • the test method is as follows.
  • Example 3 2314 87.7 Example 4 2217 84.0 Example 5 2236 84.7 Example 6 2573 97.5 Example 7 2577 97.6 Example 8 2202 83.4 Example 9 2237 84.7 Example 10 2252 85.3 Example 11 2224 84.2
  • Example 2-1A Comparative Example 1 and Comparative Example 4, and comparing Example 2-3B with Comparative Example 2, it can be seen that by providing a hydrophilic retardation layer, even a high boiling point solvent is used.
  • the polymer solution and the prepared lithium ion battery also have good rate discharge performance, and particularly show a significantly improved discharge performance under large rate discharge conditions.
  • Example 2-1B Comparing Example 2-1B with Example 3, it can be seen that drying the polar polymer binder coating at a temperature not higher than 60 ° C can significantly improve the gas permeability of the prepared polymer separator and The ionic conductivity significantly improves the performance of the final prepared lithium ion battery. Comparing Example 2-1B with Examples 4 and 5, it can be seen that controlling the concentration of the polar polymer in the polar polymer binder solution to a critical concentration can significantly improve the gas permeability of the prepared polymer separator and The ionic conductivity significantly improves the performance of the final prepared lithium ion battery.
  • Example 2-1A and Example 2-1B with Examples 8 and 9, respectively it can be seen that making the contact angle of the hydrophilic retardation layer with water not higher than 20° can further improve the finally prepared lithium.
  • the performance of the ion battery Comparing Example 10 with Example 11, it can be seen that drying the hydrophilic retardation coating layer and coating the polar polymer binder solution to form a polar polymer bonding layer can further improve the prepared polymerization.
  • the gas permeability and ionic conductivity of the separator increase the performance of the finally prepared lithium ion battery.

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Abstract

公开了一种聚合物隔膜及其制备方法以及含有该聚合物隔膜的锂离子电池，所述聚合物隔膜含有多孔基材、亲水性阻滞层以及多孔极性聚合物粘结层，亲水性阻滞层设置在所述多孔基材的至少一个表面上，亲水性阻滞层设置在所述亲水性阻滞层远离所述多孔基材的表面上。

Description

聚合物隔膜及其制备方法和应用以及锂离子电池
相关申请的交叉引用
本公开要求于2018年4月28日提交中国专利局、申请号为201810402852.1、申请名称为“聚合物隔膜及其制备方法和应用以及锂离子电池及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及一种聚合物隔膜及其制备方法和应用，本公开还涉及采用该聚合物隔膜的锂离子电池。
背景技术
锂离子电池主要由正/负极材料、电解质、隔膜及电池外壳包装材料组成。隔膜是锂离子电池的重要组成部分，用于分隔正、负极，防止电池内部短路；隔膜允许电解质离子自由通过，完成电化学充放电过程。隔膜的性能决定了电池的界面结构、内阻等，直接影响电池的倍率性能、循环性能以及安全性能(耐高温性能)等特性，性能优异的隔膜对提高电池的综合性能具有重要的作用。
由于具有原料价格低廉、制备工艺简单、机械强度高、电化学稳定性强等特点，机械拉伸法制备的聚乙烯、聚丙烯微孔膜是目前主要商用的锂离子电池隔膜。但是，商用微孔膜在熔融温度附近闭孔收缩造成电池短路，使电池具有高温下燃烧和爆炸的危险；除此之外，聚烯烃隔膜对电解液吸附性差，不利于充放电过程中锂离子的传导。
目前，在聚烯烃微孔膜两侧涂覆聚醚类(如聚氧化乙烯)、聚丙烯腈类、聚丙烯酸酯类(如聚甲基丙烯酸甲酯及其共聚物)、聚偏氟乙烯类(包括聚偏氟乙烯、以及偏氟乙烯-六氟丙烯共聚物)等极性聚合物的多孔膜是可以改善隔膜吸附电解液性能，同时降低微孔膜在熔融温度附近收缩比率的主要方法。倒相法是制备多孔膜的主要方法之一，其主要包括两种形式：(1)溶剂蒸发沉淀相分离法；(2)浸入沉淀相分离法。
在实际生产中，聚偏氟乙烯系(PVDF)涂覆技术已得到了广泛应用。聚偏氟乙烯系(PVDF)涂覆技术采用溶剂蒸发沉淀相分离法在聚烯烃微孔膜表面造孔得到PVDF多孔膜，其具体操作工艺为：将聚偏氟乙烯溶解或分散于丙酮中，并添加一定量的致孔剂DMC(二甲基碳酸酯)，形成浆液，将该浆液涂布在聚烯烃微孔膜表面并进行干燥。干燥的过程中，先挥发除去潜溶剂丙酮，再蒸发除去致孔剂DMC，从而留下孔隙。
公开内容
现有的聚偏氟乙烯系(PVDF)涂覆技术采用低沸点丙酮作为溶剂，操作安全性有待提高。本公开的发明人在研究过程中发现尽管采用高沸点的溶剂代替丙酮，可以提高操作安全性，但是采用高沸点的溶剂配制聚偏氟乙烯系聚合物溶液而制备的锂离子电池的性能明显下降，经过研究发现，其原因可能在于：采用高沸 点的溶剂配制的聚偏氟乙烯系聚合物溶液渗透性极强，聚合物溶液极易穿透隔膜而到达与涂布面相对的另一个表面，从而将聚偏氟乙烯系聚合物也带入隔膜的孔隙中，由于聚偏氟乙烯系聚合物的流动性和渗透性远低于有机溶剂，被有机溶剂携带进入隔膜的聚偏氟乙烯系聚合物通常存留在隔膜的孔隙中，堵塞隔膜，对隔膜的透气性和孔隙率产生不利影响，提高聚合物隔膜的本体阻抗，降低离子电导率，对最终制备的锂离子电池的性能产生不良影响。尽管现有的聚烯烃隔膜表面通常形成陶瓷层以提高隔膜的热稳定性以及吸附电解液的能力，但是即便具有所述陶瓷层的聚烯烃隔膜也难以阻挡聚合物溶液穿透隔膜。
针对采用高沸点的溶剂配制聚偏氟乙烯系聚合物溶液时存在的问题，本公开的发明人进行了深入的研究，发现：采用高沸点的溶剂配制聚偏氟乙烯系聚合物溶液时，如果在多孔基材(即，具有陶瓷层或不具有陶瓷层的聚烯烃多孔膜)与聚偏氟乙烯系聚合物之间设置亲水性阻滞层，能有效地抑制聚偏氟乙烯系聚合物溶液透过亲水性阻滞层而进入多孔基材中，从而有效地降低进入多孔基材中的聚偏氟乙烯系聚合物的量，提高聚合物隔膜的透气性和孔隙率，降低聚合物隔膜的本体阻抗，提高聚合物隔膜的离子电导率，使得制备的锂离子电池仍然具有较好的性能。在此基础上完成了本公开。
根据本公开的第一个方面，本公开提供了一种聚合物隔膜，该聚合物隔膜含有多孔基材；亲水性阻滞层，所述亲水性阻滞层设置在所述多孔基材的一个表面或者相对的两个表面上；以及多孔极性聚合物粘结层，所述多孔极性聚合物粘结层设置在所述亲水性阻滞层远离所述多孔基材的表面上，所述多孔极性聚合物粘结层的孔径200nm-20μm。
根据本公开的第二个方面，本公开提供了一种聚合物隔膜的制备方法，该方法包括：将亲水性阻滞浆液涂布在多孔基材的一个表面或者相对的两个表面上形成亲水性阻滞涂层，将所述亲水性阻滞涂层干燥，在所述多孔基材的表面形成亲水性阻滞层；将极性聚合物粘结剂溶液涂布在所述亲水性阻滞层远离所述多孔基材的表面上，形成极性聚合物粘结剂涂层，将所述极性聚合物粘结剂涂层进行干燥，在所述亲水性阻滞层表面形成多孔极性聚合物粘结层；或者，将所述亲水性阻滞浆液涂布在所述多孔基材的一个表面或者相对的两个表面上形成所述亲水性阻滞涂层，将所述极性聚合物粘结剂溶液涂布在所述亲水性阻滞涂层远离所述多孔基材的表面上形成所述极性聚合物粘结剂涂层，将所述亲水性阻滞涂层和所述极性聚合物粘结剂涂层进行干燥，在所述多孔基材表面形成所述亲水性阻滞层以及在所述亲水性阻滞层表面形成所述多孔极性聚合物粘结层；所述亲水性阻滞浆液含有分散介质、以及分散在所述分散介质中的亲水性无机颗粒以及粘合剂，所述极性聚合物粘结剂溶液含有有机溶剂以及分散在所述有机溶剂中的极性聚合物和造孔剂。
根据本公开的聚合物隔膜的制备方法，在配制极性聚合物粘结剂溶液时，既可以采用现有工艺中的低沸点溶剂(如丙酮)，也可以采用操作安全性更高的高沸点溶剂，还可以采用低沸点溶剂和高沸点溶剂的混合物。采用高沸点溶剂时，不仅能提高操作安全性，而且不会导致锂离子电池的性能明显下降。根据本公开的第三个方面，本公开提供了一种锂离子电池，该锂离子电池包括正极极片、负极极片以及聚合物隔膜，其中，所述聚合物隔膜为本公开第一个方面或者第三个方面所述的聚合物隔膜。
附图说明
图1和图2为实施例1-1制备的聚合物隔膜的亲水性阻滞层的表面SEM形貌图片，图1为放大500倍的照片，图2为放大5000倍的照片。
图3和图4为实施例2-1A制备的聚合物隔膜的表面SEM形貌图片，图3为放大500倍的照片，图4为放大5000倍的照片。
图5和图6为实施例2-1B制备的聚合物隔膜的表面SEM形貌图片，图5为放大500倍的照片，图6为放大5000倍的照片。
图7和图8为对比例1制备的聚合物隔膜的表面SEM形貌图片，图7为放大500倍的照片，图8为放大5000倍的照片。
图9和图10为对比例3制备的聚合物隔膜的表面SEM形貌图片，图9为放大500倍的照片，图10为放大5000倍的照片。
图11和图12为将实施例2-1A制备的聚合物隔膜与正极粘结接触面剥离后，聚合物隔膜侧(图11)以及正极侧(图12)的SEM形貌照片。
图13和图14为将实施例2-1A制备的聚合物隔膜与负极粘结接触面剥离后，聚合物隔膜侧(图13)以及负极侧(图14)的SEM形貌照片。
图15和图16分别为实施例2-1A(图15)以及对比例1(图16)制备的锂离子电池的正极与聚合物隔膜的剥离强度测试曲线图。
图17和图18分别为实施例2-1A(图17)以及对比例1(图18)制备的锂离子电池的负极与聚合物隔膜的剥离强度测试曲线图。
具体实施方式
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
根据本公开的第一个方面，本公开提供了一种聚合物隔膜，该聚合物隔膜包括多孔基材、亲水性阻滞层以及多孔极性聚合物粘结层，所述亲水性阻滞层设置在所述多孔基材的一个表面或者相对的两个表面上，且所述多孔极性聚合物粘结层设置在所述亲水性阻滞层远离所述多孔基材的表面上，或者说所述亲水性阻滞层设置在所述多孔基材和所述多孔极性聚合物粘结层之间。
根据本公开的聚合物隔膜，所述亲水性阻滞层为具有亲水特性的阻滞层。根据本公开的聚合物隔膜，所述亲水性阻滞层与水的接触角可以为40°以下，例如1°、2°、3°、4°、5°、6°、7°、8°、9°、10°、11°、12°、 13°、14°、15°、16°、17°、18°、19°、20°、21°、22°、23°、24°、25°、26°、27°、28°、29°、30°、31°、32°、33°、34°、35°、36°、37°、38°、39°或者40°。一些具体实施例中，所述亲水性阻滞层与水的接触角为20°以下。在所述亲水性阻滞层与水接触角为20°以下时，能更为明显地提高聚合物隔膜的性能，例如：更为明显地提高聚合物隔膜的透气性和离子电导率，使得采用该聚合物隔膜的锂离子电池显示出更为优异的性能。另一些具体实施例中，所述亲水性阻滞层与水的接触角为2-18°，具体可以为5-15°。所述接触角采用GB/T30693-2014塑料薄膜与水接触角的测量中规定的方法测定。
根据本公开的聚合物隔膜，所述亲水性阻滞层含有粘合剂以及亲水性无机颗粒，所述亲水性无机颗粒通过所述粘合剂相互粘合。
根据本公开的聚合物隔膜，所述亲水性无机颗粒可以为亲水性Al 2O 3颗粒、亲水性SiO 2颗粒、亲水性SnO 2颗粒、亲水性ZrO 2颗粒、亲水性TiO 2颗粒、亲水性SiC颗粒、亲水性Si 3N 4颗粒、亲水性CaO颗粒、亲水性MgO颗粒、亲水性ZnO颗粒、亲水性BaTiO 3颗粒、亲水性LiAlO 2颗粒和亲水性BaSO 4颗粒中的一种或两种以上。一些具体实施例中，所述亲水性无机颗粒为亲水性Al 2O 3颗粒和亲水性SiO 2颗粒中的一种或两种。另一些具体实施例中，所述亲水性无机颗粒为气相法亲水性SiO 2颗粒、沉淀法亲水性SiO 2颗粒和气相法亲水性Al 2O 3颗粒中的一种或两种以上。
根据本公开的聚合物隔膜，所述亲水性无机颗粒的粒径可以为1nm至10μm，如1nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm。一些具体实施例中，所述亲水性无机颗粒的粒径可以为1nm至5μm。从进一步提高聚合物隔膜的透气性和离子电导率以及采用该聚合物隔膜的锂离子电池性能的角度出发，一些具体实施例中，所述亲水性无机颗粒的粒径为10nm至1μm，又一些具体实施例中，所述亲水性无机颗粒的粒径为20nm至800nm，再一些具体实施例中，所述亲水性无机颗粒的粒径为50nm至350nm。本文中所述粒径为体积平均粒径，采用激光粒度仪测定。
根据本公开的一些实施例，所述亲水性无机颗粒的比表面积可以为10-600m 2/g，如10m 2/g、50m 2/g、100m 2/g、150m 2/g、200m 2/g、250m 2/g、300m 2/g、350m 2/g、400m 2/g、450m 2/g、500m 2/g、550m 2/g或600m 2/g。从进一步提高聚合物隔膜的透气性和离子电导率以及采用该聚合物隔膜的锂离子电池性能的角度出发，一些具体实施例中，所述亲水性无机颗粒的比表面积为100-500m 2/g，另一些具体实施例中，所述亲水性无机颗粒的比表面积为150-400m 2/g，又一些具体实施例中，所述亲水性无机颗粒的比表面积为200-400m 2/g，再一些具体实施例中，所述亲水性无机颗粒的比表面积为250-390m 2/g，另一些具体实施例中，所述亲水性无机颗粒的比表面积为300-380m 2/g。所述比表面积采用GB/T19587-2004气体吸附BET法测定固态物质比表面积方法中规定的方法测定。
根据本公开的聚合物隔膜，以所述亲水性阻滞层的总量为基准，所述亲水性无机颗粒的含量可以为50-95重量％，如50％、55％、60％、65％、70％、75％、80％、85％、90％或95％。一些具体实施例中，所述 亲水性无机颗粒的含量可以为70-95重量％，另一些具体实施例中，所述亲水性无机颗粒的含量可以为80-95重量％，又一些具体实施例中，所述亲水性无机颗粒的含量可以为85-95重量％。
根据本公开的聚合物隔膜，所述粘合剂一方面用于粘合并固定亲水性无机颗粒，另一方面还可以进一步提高聚合物隔膜的吸附电解液的能力。一些具体实施例中，所述粘合剂可以为丙烯酸酯型聚合物、苯乙烯-丙烯酸酯共聚物、聚偏氟乙烯(偏氟乙烯又称偏二氟乙烯)、偏氟乙烯-六氟丙烯共聚物、丙烯腈-丙烯酸酯共聚物、氯乙烯-丙烯酸酯共聚物和丁二烯-苯乙烯共聚物中的一种或两种以上。
根据本公开的聚合物隔膜，所述亲水性阻滞层的厚度可以为0.1-3μm，例如：0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2μm、2.1μm、2.2μm、2.3μm、2.4μm、2.5μm、2.6μm、2.7μm、2.8μm、2.9μm、或者3μm。一些具体实施例中，所述亲水性阻滞层的厚度可以为0.1-1μm，另一些具体实施例中，所述亲水性阻滞层的厚度可以为0.3-0.8μm。
根据本公开的聚合物隔膜，所述多孔基材含有多孔聚合物层，可以用于溶胀液体电解液并传输锂离子。一些具体实施例中，所述多孔聚合物层为多孔聚烯烃层，例如多孔聚乙烯(PE)层、多孔聚丙烯(PP)层、多孔聚乙烯和多孔聚丙烯复合层中的一种或两种以上。所述多孔聚乙烯和多孔聚丙烯复合层可以为PE/PP/PE复合基材层。
根据本公开的聚合物隔膜，所述多孔聚合物层的厚度可以为1-50μm，如1μm、5μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm或50μm。一些具体实施例中，所述多孔聚合物层的厚度可以为5-20μm，另一些具体实施例中，所述多孔聚合物层的厚度可以为8-15μm。
根据本公开的聚合物隔膜，所述多孔基材还可以含有陶瓷层，所述陶瓷层用于提高多孔聚合物层的热稳定性、力学性能和电解液吸附能力。一些具体实施例中，所述陶瓷层中的陶瓷颗粒可以为由选自Al 2O 3、SiO 2、SnO 2、ZrO 2、TiO 2、SiC、Si 3N 4、CaO、MgO、ZnO、BaTiO 3、LiAlO 2和BaSO 4中的一种或两种以上烧结形成的陶瓷颗粒。一些具体实施例中，所述陶瓷层的厚度可以为1-5μm，如1μm、1.5μm、2μm、2.5μm、3μm、3.5μm、4μm、4.5μm或5μm。一些具体实施例中，所述陶瓷层的厚度可以为1.5-3μm。另一些具体实施例中，所述陶瓷层的厚度大于所述亲水性阻滞层的厚度。
根据本公开的聚合物隔膜含有陶瓷层时，所述陶瓷层设置在多孔聚合物层的一个表面或者相对的两个表面上。根据本公开的一些实施例，陶瓷层设置在多孔聚合物层的一个表面上，所述亲水性阻滞层设置在所述多孔聚合物层的另一个表面上、所述亲水性阻滞层设置在所述陶瓷层的表面上、或者所述亲水性阻滞层同时设置在所述多孔聚合物层的另一个表面上和所述陶瓷层的表面上。根据本公开的另一些实施例，陶瓷层设置在多孔聚合物层相对的两个表面上，所述亲水性阻滞层设置在单侧的陶瓷层远离多孔聚合物层的表面上、或者所述亲水性阻滞层同时设置在两侧的陶瓷层远离所述多孔聚合物层的表面上。根据本公开的一些实施例，所述陶瓷层可以设置在所述多孔聚合物层和所述亲水性阻滞层之间，也可以是多孔聚合物层设置在所述陶瓷 层和所述亲水性阻滞层之间，还可以为上述两种方式的组合。
根据本公开的聚合物隔膜，所述多孔极性聚合物粘结层用于降低多孔基材在熔融温度附近的收缩比率，同时起到粘结的作用，将聚合物隔膜与电池的正极极片或负极极片粘结在一起，还可以提高多孔基材的吸附电解液的能力。所述多孔极性聚合物粘结层中的极性聚合物可以为能实现上述功能的极性聚合物，其具体实例可以包括但不限于聚偏氟乙烯(PVDF)、偏氟乙烯-六氟丙烯共聚物(P(VDF-HFP)，或称为偏氟乙烯和六氟丙烯的共聚物)、以及偏氟乙烯-丙烯酸酯共聚物(或称为偏二氟乙烯和丙烯酸酯的共聚物)中的一种或两种以上。
根据本公开的聚合物隔膜，所述多孔极性聚合物粘结层的厚度可以为0.1-10μm，如0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1.0μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm。在本公开的一些具体实施例中，多孔极性聚合物粘结层的厚度可以为0.2-5μm，在本公开的另一些具体实施例中，多孔极性聚合物粘结层的厚度可以为0.7-3μm，在本公开的又一些具体实施例中，多孔极性聚合物粘结层的厚度可以为0.8-1.5μm。
根据本公开的聚合物隔膜，多孔极性聚合物粘结层中的孔包括具有第一孔径的孔和具有第二孔径的孔，所述第一孔径可以为5-20μm，具体如5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm、15μm、16μm、17μm、18μm、19μm、20μm等；所述第二孔径可以为200nm-2μm，具体如200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2μm等。一些具体实施例中，所述第一孔径为5-10μm，所述第二孔径为200nm-2μm。根据本公开的聚合物隔膜中的多孔极性聚合物粘结层具有两级孔径结构，本公开的发明人在偶然间发现，大的孔径可以减少聚合物隔膜与正、负极面的接触面积，不阻挡锂离子传输，但其孔径过大又会造成粘结层的强度较差，粘结层上的孔洞形貌的均匀性差，且聚合物隔膜与正、负极之间的导电性和粘附性差；小的孔径可以提高孔洞形貌的均匀性，保证粘结层强度，进一步提高聚合物隔膜与正、负极之间的导电性和粘附性，但粘结性过小会阻挡锂离子传输，影响电池的性能。本公开提供的多孔极性聚合物粘结层两级孔径结合有效解决了上述技术问题，进一步提高了电池性能。需要说明的是，本文中所述孔径为个数平均孔径。
一些具体实施例中，所述多孔极性聚合物粘结层的孔隙率为20-80％，具体如20％、30％、40％、50％、60％、70％、80％等。
一些具体实施例中，所述多孔极性聚合物粘结层包括贯通多孔极性聚合物粘结层的通孔。
本公开中，多孔极性聚合物粘结层中的孔径根据多孔极性聚合物粘结层表面的SEM图像定性测定；多孔极性聚合物粘结层的孔隙率采用正丁醇吸收法，将隔膜浸入已知密度的正丁醇溶剂中，通过测量隔膜浸润前后的质量差，计算隔膜被液体所占据的空隙体积，作为隔膜孔隙率。
根据本公开的聚合物隔膜，所述亲水性阻滞层以及所述多孔极性聚合物粘结层可以设置在多孔基材的至少一个表面上，具体的，所述亲水性阻滞层以及所述多孔极性聚合物粘结层可以设置在多孔基材的一面， 也可以设置在多孔基材的两面。在本公开的一些具体实施例中，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面，即设置在所述亲水性阻滞层远离所述多孔基材的表面上。
根据本公开的聚合物隔膜，在一种实施方式中，该聚合物隔膜由多孔基材、亲水性阻滞层和多孔极性聚合物粘结层组成，所述多孔基材为多孔聚合物层，所述亲水性阻滞层附着在所述多孔基材的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面。根据该实施方式，可以在多孔基材的一个表面依次设置所述亲水性阻滞层和所述多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔聚合物层|亲水性阻滞层|多孔极性聚合物粘结层)，也可以在多孔基材的两个相对的表面各自依次设置所述亲水性阻滞层和所述多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔极性聚合物粘结层|亲水性阻滞层|多孔聚合物层|亲水性阻滞层|多孔极性聚合物粘结层)。
根据本公开的聚合物隔膜，在另一种实施方式中，该聚合物隔膜由多孔基材、亲水性阻滞层和多孔极性聚合物粘结层组成，所述多孔基材由多孔聚合物层和陶瓷层组成。根据该实施方式，在一个实施例中，所述陶瓷层附着在所述多孔聚合物层的表面，所述亲水性阻滞层附着在所述陶瓷层的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面(即，聚合物隔膜具有以下结构：多孔聚合物层|陶瓷层|亲水性阻滞层|多孔极性聚合物粘结层)。在另一个实施例中，所述多孔聚合物层附着在所述陶瓷层的表面，所述亲水性阻滞层附着在所述多孔聚合物层的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面(即，聚合物隔膜具有以下结构：陶瓷层|多孔聚合物层|亲水性阻滞层|多孔极性聚合物粘结层)。在又一个实施例中，所述陶瓷层附着在所述多孔聚合物层的表面，所述陶瓷层和所述多孔聚合物层的另一个表面各自依次附着亲水性阻滞层和多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔极性聚合物粘结层|亲水性阻滞层|陶瓷层|多孔聚合物层|亲水性阻滞层|多孔极性聚合物粘结层)。
根据本公开的聚合物隔膜，其总厚度可以为常规选择，一般可以为5-50μm，如5μm、6μm、7μm、8μm、9μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm或50μm。一些具体实施例中，聚合物隔膜的总厚度可以为8-30μm，又一些具体实施例中，聚合物隔膜的总厚度可以为10-20μm。
根据本公开的聚合物隔膜，具有较高的透气性。一般地，根据本公开的聚合物隔膜，Gurley值为100-900Sec/100mL，如100Sec/100mL、150Sec/100mL、200Sec/100mL、250Sec/100mL、300Sec/100mL、350Sec/100mL、400Sec/100mL、450Sec/100mL、500Sec/100mL、550Sec/100mL、600Sec/100mL、650Sec/100mL、700Sec/100mL、750Sec/100mL、800Sec/100mL、850Sec/100mL或900Sec/100mL。一些具体实施例中，聚合物隔膜的Gurley值可以为120-600Sec/100mL，另一些具体实施例中，聚合物隔膜的Gurley值可以为120-500Sec/100mL。又一些具体实施例中，所述聚合物隔膜的Gurley值可以为150-350Sec/100mL，如200-300Sec/100mL。需要说明的是，Gurley值可以用来表征透气率，它是指特定量的空气在特定的压力下通过特定面积的隔膜所需要的时间，与孔隙度、孔径、厚度和孔的曲折度有关，是衡量隔膜透过性好坏的一个量度。
与现有的聚合物隔膜中用于提高隔膜热稳定性和电解液吸附能力的陶瓷层相比，根据本公开的聚合物隔膜中的亲水性阻滞层，亲水性更强，能有效地阻滞制备过程中极性聚合物进入多孔基材中。与现有的聚合物隔膜相比，根据本公开的聚合物隔膜，多孔极性聚合物粘结层中的孔的孔径更大(现有的聚合物隔膜的多孔极性聚合物粘结层中的孔径通常为0.5-1μm，根据本公开的聚合物隔膜的多孔极性聚合物粘结层中的孔径可以为3μm以上，通常为3-10μm，如3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm)，多孔极性聚合物粘结层为多层丝网交织结构，所述亲水性阻滞层的部分表面通过所述多层丝网交织结构而暴露可见；然而现有的聚合物隔膜中的多孔极性聚合物粘结层更为致密，呈蜂窝状。
根据本公开的第二个方面，本公开提供了一种制备聚合物隔膜的方法，该方法包括：利用亲水性阻滞浆液在多孔基材的一个表面或者相对的两个表面上形成亲水性阻滞层；利用极性聚合物粘结剂溶液在所述亲水性阻滞层远离所述多孔基材的表面上形成多孔极性聚合物粘结层，所述亲水性阻滞浆液含有分散介质、以及分散在所述分散介质中的亲水性无机颗粒以及粘合剂，所述极性聚合物粘结剂溶液含有有机溶剂以及分散在所述有机溶剂中的极性聚合物(或称极性聚合物粘结剂)和造孔剂。该方法操作简单、方便，易于实现和工业化生产，且制备过程中极性聚合物溶液不会渗透到多孔基材的孔隙中，保证了聚合物隔膜具有较低的本体阻抗和较高的离子电导率，采用该方法制备获得的聚合物隔膜用于锂离子电池时，不会使锂离子电池的而性能下降或对其产生其它不利影响。本领域技术人员可以理解，该方法可以用于制备本公开第一个方面的聚合物隔膜。
根据本公开的聚合物隔膜的制备方法，在一些实施例中，所述方法具体包括：将亲水性阻滞浆液涂布在所述多孔基材的一个表面或者相对的两个表面上形成亲水性阻滞涂层，将所述亲水性阻滞涂层干燥，在多孔基材的表面形成所述亲水性阻滞层；将所述极性聚合物粘结剂溶液涂布在所述亲水性阻滞层远离所述多孔基材的表面上形成极性聚合物粘结剂涂层，将所述极性聚合物粘结剂涂层进行干燥，在亲水性阻滞层表面形成多孔极性聚合物粘结层。将亲水性阻滞涂层干燥形成亲水性阻滞层后涂布极性聚合物粘接剂溶液，这样能进一步提高最终制备的聚合物隔膜的透气性和离子电导率，并进一步提高采用该聚合物隔膜的锂离子电池的性能。
根据本公开的聚合物隔膜的制备方法，可以将亲水性阻滞涂层干燥形成亲水性阻滞层后涂布极性聚合物粘接剂溶液，也可以不将亲水性阻滞涂层干燥，而是直接在亲水性阻滞涂层表面涂布极性聚合物粘接剂溶液。在一些实施例中，所述方法具体包括：将亲水性阻滞浆液涂布在多孔基材的一个表面或者相对的两个表面上形成亲水性阻滞涂层，将所述极性聚合物粘结剂溶液涂布在所述亲水性阻滞涂层远离所述多孔基材的表面上形成极性聚合物粘结剂涂层，将所述亲水性阻滞涂层和所述极性聚合物粘结剂涂层进行干燥，在多孔基材表面形成亲水性阻滞层以及在亲水性阻滞层表面形成多孔极性聚合物粘结层。根据本公开的聚合物隔膜的制备方法，在一些实施例中，所述制备方法也可以包括如下步骤：将亲水性阻滞浆液涂布在多孔基材的至少一个表面(如一个表面、相对的两个表面等)形成亲水性阻滞涂层，可选地将所述亲水性阻滞涂层干燥，形成亲水性阻滞层；将极性聚合物粘结剂溶液涂布在所述亲水性阻滞涂层或者所述亲水性阻滞层的表面形成极性聚合物粘结剂涂层；将所述亲水性阻滞涂层和所述极性聚合物粘结剂涂层进行干燥，形成亲水性阻滞层和多孔极性聚合物粘结层，或者将所述极性聚合物粘结剂涂层进行干燥，形成多孔极性聚合物粘结层。
根据本公开的聚合物隔膜的制备方法，所述多孔基材可以为多孔聚合物膜，也可以为多孔聚合物膜和 陶瓷膜的复合膜。一些实施例中，所述多孔聚合物膜可以为多孔聚烯烃膜，一些具体实施例中，多孔聚合物膜可以为多孔聚乙烯膜、多孔聚丙烯膜、多孔聚乙烯和多孔聚丙烯复合膜。所述多孔聚乙烯和多孔聚丙烯复合膜可以为PE/PP/PE复合膜。所述陶瓷膜中的陶瓷可以为由选自Al 2O 3、SiO 2、SnO 2、ZrO 2、TiO 2、SiC、Si 3N 4、CaO、MgO、ZnO、BaTiO 3、LiAlO 2和BaSO 4中的一种或两种以上烧结形成的陶瓷颗粒，即所述陶瓷膜中的陶瓷颗粒可以为选自Al 2O 3颗粒、SiO 2颗粒、SnO 2颗粒、ZrO 2颗粒、TiO 2颗粒、SiC颗粒、Si 3N 4颗粒、CaO颗粒、MgO颗粒、ZnO颗粒、BaTiO 3颗粒、LiAlO 2颗粒和BaSO 4颗粒中的一种或两种以上。所述复合膜中，所述多孔聚合物膜的厚度可以为1-50μm，如1μm、1.5μm、2μm、2.5μm、3μm、3.5μm、4μm、4.5μm、5μm、5.5μm、6μm、6.5μm、7μm、7.5μm、8μm、8.5μm、9μm、9.5μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm或50μm。一些具体实施例中，所述陶瓷膜的厚度可以为5-20μm，另一些具体实施例中，所述陶瓷膜的厚度可以为8-15μm。又一些具体实施例中，所述陶瓷膜的厚度可以为1-5μm，又一些具体实施例中，所述陶瓷膜的厚度可以为1.5-3μm。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液可以含有分散介质、以及分散在所述分散介质中的亲水性无机颗粒以及粘合剂。
根据本公开的聚合物隔膜的制备方法，所述亲水性无机颗粒的粒径可以为1nm至10μm，如1nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm。一些具体实施例中，所述亲水性无机颗粒的粒径可以为1nm至5μm。从进一步提高最终制备的聚合物隔膜的透气性和离子电导率，以及采用该聚合物隔膜的锂离子电池性能的角度出发，一些实施例中，所述亲水性无机颗粒的粒径可以为1nm至2μm，另一些具体实施例中，所述亲水性无机颗粒的粒径为10nm至1μm，另一些具体实施例中，所述亲水性无机颗粒的粒径为20nm至800nm，又一些具体实施例中，所述亲水性无机颗粒的粒径为50nm至350nm。
根据本公开的聚合物隔膜的制备方法，所述亲水性无机颗粒的比表面积可以为10-600m 2/g，如10m 2/g、50m 2/g、100m 2/g、150m 2/g、200m 2/g、250m 2/g、300m 2/g、350m 2/g、400m 2/g、450m 2/g、500m 2/g、550m 2/g或600m 2/g。从进一步提高最终制备的聚合物隔膜的透气性和离子电导率以及采用该聚合物隔膜的锂离子电池性能的角度出发，所述亲水性无机颗粒的比表面积可以为100-500m 2/g，一些具体实施例中，所述亲水性无机颗粒的比表面积为150-400m 2/g，另一些具体实施例中，所述亲水性无机颗粒的比表面积为200-400m 2/g，再一些具体实施例中，所述亲水性无机颗粒的比表面积为250-390m 2/g，又一些具体实施例中，所述亲水性无机颗粒的比表面积为300-380m 2/g。所述比表面积采用GB/T19587-2004气体吸附BET法测定固态物质比表面积方法测定。
根据本公开的聚合物隔膜的制备方法，所述亲水性无机颗粒的具体实例可以包括但不限于亲水性Al 2O 3颗粒、亲水性SiO 2颗粒、亲水性SnO 2颗粒、亲水性ZrO 2颗粒、亲水性TiO 2颗粒、亲水性SiC颗粒、亲水性Si 3N 4颗粒、亲水性CaO颗粒、亲水性MgO颗粒、亲水性ZnO颗粒、亲水性BaTiO 3颗粒、亲水性LiAlO 2 颗粒、以及亲水性BaSO 4颗粒中的一种或两种以上。一些具体实施例中，所述亲水性无机颗粒为亲水性Al 2O 3颗粒和亲水性SiO 2颗粒中的一种或两种。另一些具体实施例中，所述亲水性无机颗粒为气相法亲水性SiO 2颗粒、沉淀法亲水性SiO 2颗粒和气相法亲水性Al 2O 3颗粒中的一种或两种以上。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液中，所述粘合剂可以为丙烯酸酯型聚合物、苯乙烯-丙烯酸酯共聚物、聚偏氟乙烯、偏氟乙烯-六氟丙烯共聚物、丙烯腈-丙烯酸酯共聚物、氯乙烯-丙烯酸酯共聚物和丁二烯-苯乙烯共聚物中的一种或两种以上。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液中，分散介质可以根据亲水性无机颗粒以及粘合剂的种类进行选择，以能使得亲水性无机颗粒和粘合剂形成均匀稳定的浆液为准。所述分散介质的具体实例可以包括但不限于水、乙醇、异丙醇、环己烷、四氢呋喃、二氯甲烷和三氯甲烷中的一种或两种以上。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液中，亲水性无机颗粒的含量可以为50-95重量％，优选为70-95重量％，如50重量％、55重量％、60重量％、65重量％、70重量％、75重量％、80重量％、85重量％、90重量％或95重量％。一些具体实施例中，所述亲水性无机颗粒的含量可以为80-95重量％，另一些具体实施例中，所述亲水性无机颗粒的含量可以为85-95重量％。粘合剂的用量可以根据亲水性无机颗粒的用量进行选择，以能将亲水性无机颗粒粘合并固定为准。一般地，所述亲水性阻滞浆液中，相对于100重量份亲水性无机颗粒，所述粘合剂的含量可以为1-30重量份，如1重量份、2重量份、3重量份、4重量份、5重量份、6重量份、7重量份、8重量份、9重量份、10重量份、11重量份、12重量份、13重量份、14重量份、15重量份、16重量份、17重量份、18重量份、19重量份、20重量份、21重量份、22重量份、23重量份、24重量份、25重量份、26重量份、27重量份、28重量份、29重量份或30重量份。一些具体实施例中，相对于100重量份亲水性无机颗粒，所述粘合剂的含量可以为2-25重量份，另一些具体实施例中，相对于100重量份亲水性无机颗粒，所述粘合剂的含量可以为5-20重量份。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液还可以含有分散剂，以进一步提高亲水性阻滞浆液的稳定性。所述分散剂可以为常见的可以促进无机颗粒在液体介质中的分散性的物质，其具体实例可以包括但不限于聚乙烯醇(PVA)和聚丙烯酸钠(PAANa)中的一种或两种。所述分散剂的用量可以为常规选择。一般地，相对于100重量份亲水性无机颗粒，所述分散剂的用量可以为0.1-10重量份，如0.1重量份、0.2重量份、0.3重量份、0.4重量份、0.5重量份、0.6重量份、0.7重量份、0.8重量份、0.9重量份、1重量份、2重量份、3重量份、4重量份、5重量份、6重量份、7重量份、8重量份、9重量份或10重量份。一些具体实施例中，相对于100重量份亲水性无机颗粒，所述分散剂的用量可以为0.2-5重量份，另一些具体实施例中，相对于100重量份亲水性无机颗粒，所述分散剂的用量可以为0.3-2重量份。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液还可以含有增稠剂，以进一步提高亲水性阻滞浆液的可涂布性能。所述增稠剂可以为纤维素型增稠剂和聚丙烯酸酯类碱溶胀型增稠剂(如巴斯夫Latekoll D增稠剂)中的一种或两种。相对于100重量份亲水性无机颗粒，所述增稠剂的用量可以为0.1-10 重量份，如0.1重量份、0.2重量份、0.3重量份、0.4重量份、0.5重量份、0.6重量份、0.7重量份、0.8重量份、0.9重量份、1重量份、2重量份、3重量份、4重量份、5重量份、6重量份、7重量份、8重量份、9重量份或10重量份。一些具体实施例中，相对于100重量份亲水性无机颗粒，所述增稠剂的用量可以为0.5-5重量份，另一些具体实施例中，相对于100重量份亲水性无机颗粒，所述增稠剂的用量可以为0.8-2重量份。
根据本公开的聚合物隔膜的制备方法，可以将，将所述亲水性阻滞浆液的pH值调节为碱性，具体的，所述亲水性阻滞浆液的pH值可以为8-10，如8、8.5、9、9.5或10。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液的固含量优选为2-30重量％，如2重量％、5重量％、10重量％、15重量％、20重量％、25重量％、30重量％。一些具体实施例中，所述亲水性阻滞浆液的固含量可以为5-25重量％。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞浆液在所述多孔基材表面的涂布量可以根据预期的亲水性阻滞层的厚度进行选择。一般地，所述亲水性阻滞浆液的涂布量使得所述亲水性阻滞层的厚度为0.1-3μm，例如：0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2μm、2.1μm、2.2μm、2.3μm、2.4μm、2.5μm、2.6μm、2.7μm、2.8μm、2.9μm、或者3μm。一些具体实施例中，所述亲水性阻滞浆液的涂布量使得所述亲水性阻滞层的厚度为0.1-1μm，另一些具体实施例中，所述亲水性阻滞浆液的涂布量使得所述亲水性阻滞层的厚度为0.3-0.8μm。
根据本公开的聚合物隔膜的制备方法，将亲水性阻滞涂层干燥的温度可以为10-120℃，如10℃、20℃、30℃、40℃、50℃、60℃、70℃、80℃、90℃、100℃、110℃、120℃。一些具体实施例中，将亲水性阻滞涂层干燥的温度为不高于100℃。另一些具体实施例中，所述干燥的温度为不高于80℃，例如10-80℃，具体可以为10℃、15℃、20℃、25℃、30℃、35℃、40℃、45℃、50℃、55℃、60℃、65℃、70℃、75℃、或者80℃。一些具体实施例中，所述干燥的温度为40-60℃，如50-60℃。将亲水性阻滞涂层干燥可以在常压下进行，也可以在减压下进行。又一些具体实施例中，将亲水性阻滞涂层干燥可以在常压下进行。一些具体实施例中，将亲水性阻滞涂层干燥可以在鼓风干燥箱中进行。将亲水性阻滞涂层干燥的持续时间可以根据干燥的温度以及采用的分散剂的种类进行选择。一般地，将亲水性阻滞涂层干燥的持续时间可以为0.1-24小时，如0.1小时、1小时、3小时、5小时、10小时、15小时、20小时或24小时。一些具体实施例中，将亲水性阻滞涂层干燥的持续时间可以为5-18小时，另一些具体实施例中，将亲水性阻滞涂层干燥的持续时间可以为8-15小时。
根据本公开的聚合物隔膜的制备方法，所述亲水性阻滞层与水的接触角可以为40°以下，例如1°、2°、3°、4°、5°、6°、7°、8°、9°、10°、11°、12°、13°、14°、15°、16°、17°、18°、19°、20°、21°、22°、23°、24°、25°、26°、27°、28°、29°、30°、31°、32°、33°、34°、35°、36°、37°、38°、39°、或者40°。一些具体实施例中，所述亲水性阻滞层与水的接触角为20°以下。在所述亲水性阻滞层与水接触角为20°以下时，能更 为明显地提高聚合物隔膜的性能，例如：更为明显地提高聚合物隔膜的透气性和离子电导率，使得采用该聚合物隔膜的锂离子电池显示出更为优异的性能。另一些具体实施例中，上述得到的亲水性阻滞层与水的接触角为2-18°，具体可以为5-15°。所述接触角采用GB/T30693-2014塑料薄膜与水接触角的测量中规定的方法测定。
根据本公开的聚合物隔膜的制备方法，所述极性聚合物粘结剂溶液含有有机溶剂以及分散在所述有机溶剂中的极性聚合物粘结剂和造孔剂。
根据本公开的聚合物隔膜的制备方法，所述极性聚合物粘结剂可以为聚偏氟乙烯、偏氟乙烯-六氟丙烯共聚物、以及偏氟乙烯-丙烯酸酯共聚物中的一种或两种以上。
根据本公开的聚合物隔膜的制备方法，所述有机溶剂可以为低沸点有机溶剂(沸点低于60℃的有机溶剂)，例如丙酮；也可以为高沸点溶剂，例如沸点为60℃以上的溶剂；还可以为低沸点溶剂和高沸点溶剂的混合物。对于低沸点溶剂和高沸点溶剂的混合物，从进一步提高操作安全性的角度出发，可以将低沸点溶剂的含量控制为不高于发生燃爆的安全阀值。
在一种实施方式中，所述有机溶剂为低沸点溶剂，具体可以为丙酮。根据该实施方式，为了使得制备的聚合物隔膜和锂离子电池显示出更为优异的性能，特别是采用该聚合物隔膜制备的锂离子电池显示出明显提高的大倍率放电性能和高温性能，所述亲水性无机颗粒的粒径可以为1nm至2μm、10nm至1μm、20nm至800nm、或者50nm至350nm，所述亲水性阻滞层与水的接触角可以为20°以下，并且将所述极性聚合物粘结剂涂层进行干燥在不高于60℃的温度下进行。
在另一种实施方式中，所述有机溶剂为高沸点溶剂，例如沸点为60℃以上的有机溶剂(如60-260℃)，一些具体实施例中，有机溶剂为沸点为120℃以上的有机溶剂(如120-260℃)，另一些具体实施例中，有机溶剂为沸点为140℃以上的有机溶剂(如140-260℃)。再一些实施例中，所述有机溶剂的沸点为145-260℃，如150-230℃。所述有机溶剂的具体实例可以包括但不限于磷酸三乙酯、N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、以及二甲基亚砜中的一种或两种以上。根据该实施方式，能提高操作安全性。
在又一种实施方式中，所述有机溶剂为低沸点溶剂和高沸点溶剂的混合物。所述低沸点溶剂和所述高沸点溶剂各自与前文所述相同。在该实施方式中，以有机溶剂的总量为基准，高沸点溶剂的含量可以为0.1-99.9重量％，具体可以为20-90重量％，更具体可以为40-70重量％，进一步可以为45-55重量％；低沸点溶剂的含量可以为0.1-99.9重量％，具体可以为10-80重量％，更具体可以为30-60重量％，进一步可以为45-55重量％。
根据本公开的聚合物隔膜的制备方法，所述造孔剂为在将所述亲水性阻滞涂层和所述极性聚合物粘结剂涂层同时进行干燥，或者将所述极性聚合物粘结剂涂层进行干燥时能形成挥发性气体的物质。由此，进行上述干燥时，在有机溶剂自身成孔的基础上辅助成孔。所述造孔剂可以为在涂布温度下为固体，而在上述干燥条件下能形成挥发性气体的物质。所述造孔剂具体可以为干冰。
根据本公开的聚合物隔膜的制备方法，所述极性聚合物粘结剂溶液中，相对于100重量份有机溶剂，所述造孔剂的重量比可以为0.5-5重量份，具体如0.5重量份、1重量份、1.5重量份、2重量份、2.5重量份、3重量份、3.5重量份、4重量份、4.5重量份、5重量份等，一些具体实施例中，相对于100重量份有机溶剂，所述造孔剂的重量比可以为0.8-3重量份，另一些具体实施例中，相对于100重量份有机溶剂，所述造孔剂的重量比可以为1-2重量份。
根据本公开的聚合物隔膜的制备方法，所述极性聚合物粘结剂溶液中极性聚合物粘结剂的浓度为1-30重量％，如2重量％、5重量％、10重量％、15重量％、20重量％、25重量％、30重量％。一些具体实施例中，所述极性聚合物粘结剂溶液中极性聚合物的浓度为2-25重量％。从进一步提高最终制备的聚合物隔膜的性能以及采用该聚合物隔膜的锂离子电池性能的角度出发，所述极性聚合物粘结剂溶液中极性聚合物粘结剂的浓度可以为5-20重量％。一些具体实施例中，所述极性聚合物粘结剂溶液中极性聚合物粘结剂的浓度为临界浓度(一般为8-15重量％，具体可以为10-12重量％)。所述临界浓度是指极性聚合物粘结剂溶液透过多孔基材的浓度，可以在25℃、1标准大气压且相对湿度为RH45％～55％的环境下，将极性聚合物粘结剂溶液涂布在多孔基材一个表面，观察极性聚合物粘结剂溶液在1小时内是否透过多孔基材，将处于透过多孔基材的浓度和不透过多孔基材的浓度之间的浓度作为临界浓度。在所述极性聚合物粘结剂的浓度为临界浓度时，极性聚合物粘结剂在溶液中，微观上呈凝胶状，单分子难以流动扩散，这样能加强极性聚合物分子之间的相互作用，在溶剂蒸发过程中形成理想的物理交联网络结构，从而使得聚合物隔膜具有更为优异的透气性和离子电导率，采用该聚合物隔膜的锂离子电池具有更为优异的性能。
根据本公开的聚合物隔膜的制备方法，所述极性聚合物粘结剂溶液的涂布量可以根据预期的极性聚合物粘结层的厚度进行选择。所述极性聚合物粘结剂溶液的涂布量可以使得最终形成的多孔极性聚合物粘结层的厚度为0.1-10μm，如0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1.0μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm。一些具体实施例中，极性聚合物粘结剂溶液的涂布量可以使得最终形成的多孔极性聚合物粘结层的厚度可以为0.2-5μm，另一些具体实施例中，极性聚合物粘结剂溶液的涂布量可以使得最终形成的多孔极性聚合物粘结层的厚度可以为0.7-3μm，又一些具体实施例中，极性聚合物粘结剂溶液的涂布量可以使得最终形成的多孔极性聚合物粘结层的厚度可以为0.8-1.5μm。
根据本公开的聚合物隔膜的制备方法，将极性聚合物粘结剂涂层干燥可以在不高于120℃的温度下进行。一些具体实施例中，将极性聚合物粘结剂涂层干燥可以在不高于60℃的温度下进行，可以为10-60℃，例如：10℃、15℃、20℃、25℃、30℃、35℃、40℃、45℃、50℃、55℃、或者60℃。在不高于60℃的温度下将极性聚合物粘结剂涂层干燥，能使得极性聚合物粘结层具有更为优异的孔结构，从而能进一步提高最终制备的聚合物隔膜的透气性和离子电导率，并进一步提高采用该聚合物隔膜的锂离子电池的性能。另一些具体实施例中，将极性聚合物粘结剂涂层干燥在20-55℃的温度下进行。又一些具体实施例中，将极性聚合物粘结剂涂层干燥在30-45℃的温度下进行。将极性聚合物粘结剂涂层干燥的持续时间可以根据干燥的温度进 行选择。具体地，将极性聚合物粘结剂涂层干燥的持续时间可以为0.1-36小时，具体如0.1小时、1小时、5小时、10小时、15小时、20小时、25小时、30小时、36小时等。一些具体实施例中，将极性聚合物粘结剂涂层干燥的持续时间可以为5-30小时，另一些具体实施例中，将极性聚合物粘结剂涂层干燥的持续时间可以为8-24小时，又一些具体实施例中，10-24小时。
根据本公开的聚合物隔膜的制备方法，上述涂布亲水性阻滞浆液和极性聚合物粘结剂溶液可以采用常规涂布方法，例如辊涂法、喷涂法、浸入涂布法和丝网印刷法中的一种或两种以上的组合。
根据本公开的方法，制备的聚合物隔膜中，可以在多孔基材的单面形成亲水性阻滞层和多孔极性聚合物粘结层，也可以在多孔基材的双面形成亲水性阻滞层和多孔极性聚合物粘结层。
根据本公开的方法，在一种实施方式中，最终制备的聚合物隔膜由多孔基材、亲水性阻滞层和多孔极性聚合物粘结层组成，所述多孔基材为多孔聚合物膜，所述亲水性阻滞层附着在所述多孔基材的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面。根据该实施方式，可以在多孔基材的一个表面依次设置所述亲水性阻滞层和所述多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔聚合物膜|亲水性阻滞层|多孔极性聚合物粘结层)，也可以在多孔基材的两个相对的表面各自设置所述亲水性阻滞层和所述多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔极性聚合物粘结层|亲水性阻滞层|多孔聚合物膜|亲水性阻滞层|多孔极性聚合物粘结层)。
根据本公开的方法，在另一种实施方式中，最终制备的聚合物隔膜由多孔基材、亲水性阻滞层和多孔极性聚合物粘结层组成，所述多孔基材为多孔聚合物膜和陶瓷膜的复合膜。根据该实施方式，在一个实施例中，所述陶瓷膜附着在所述多孔聚合物膜的表面，所述亲水性阻滞层附着在所述陶瓷膜的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面(即，聚合物隔膜具有以下结构：多孔聚合物膜|陶瓷膜|亲水性阻滞层|多孔极性聚合物粘结层)。在另一个实施例中，所述多孔聚合物膜附着在所述陶瓷层的表面，所述亲水性阻滞层附着在所述多孔聚合物膜的表面，所述多孔极性聚合物粘结层附着在所述亲水性阻滞层的表面(即，聚合物隔膜具有以下结构：陶瓷膜|多孔聚合物膜|亲水性阻滞层|多孔极性聚合物粘结层)。在又一个实施例中，陶瓷膜附着在多孔聚合物膜的表面，所述陶瓷膜和所述多孔聚合物膜的另一个表面各自依次附着亲水性阻滞层和多孔极性聚合物粘结层(即，聚合物隔膜具有以下结构：多孔极性聚合物粘结层|亲水性阻滞层|陶瓷膜|多孔聚合物膜|亲水性阻滞层|多孔极性聚合物粘结层)。
根据本公开的第三个方面，本公开提供了由本公开第二个方面所述方法制备的聚合物隔膜。该聚合物隔膜通过设置亲水性阻滞层，使得在制备多孔极性聚合物粘结层时极性聚合物粘结剂溶液不会渗透到多孔基材的孔隙中，聚合物隔膜具有较低的本体阻抗和较高的离子电导率，不会引起采用该聚合物隔膜的锂离子电池的性能下降，且极性聚合物粘结剂溶液可以采用较高沸点的有机溶剂，能够明显提高操作安全性。
由本公开第二个方面所述方法制备的聚合物隔膜，其总厚度可以为常规选择，一般可以为5-50μm，如5μm、6μm、7μm、8μm、9μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm或50μm。一些具 体实施例中，聚合物隔膜的总厚度可以为8-30μm，另一些具体实施例中，聚合物隔膜的总厚度可以为10-20μm。
由本公开第二个方面所述方法制备的聚合物隔膜，具有较高的透气性。一般地，由本公开第二个方面所述方法制备的聚合物隔膜，Gurley值为100-900Sec/100mL，如100Sec/100mL、150Sec/100mL、200Sec/100mL、250Sec/100mL、300Sec/100mL、350Sec/100mL、400Sec/100mL、450Sec/100mL、500Sec/100mL、550Sec/100mL、600Sec/100mL、650Sec/100mL、700Sec/100mL、750Sec/100mL、800Sec/100mL、850Sec/100mL或900Sec/100mL。一些具体实施例中，聚合物隔膜的Gurley值可以为120-600Sec/100mL，另一些具体实施例中，聚合物隔膜的Gurley值可以为120-500Sec/100mL。又一些具体实施例中，由本公开第二个方面所述方法制备的聚合物隔膜的Gurley值为150-350Sec/100mL，具体如200-300Sec/100mL。
与现有的聚合物隔膜中用于提高隔膜热稳定性和电解液吸附能力的陶瓷层相比，由本公开第二个方面所述方法制备的聚合物隔膜中的亲水性阻滞层，亲水性更强，能有效地阻滞制备过程中极性聚合物进入多孔基材中。与现有的聚合物隔膜相比，由本公开第二个方面所述方法制备的聚合物隔膜，多孔极性聚合物粘结层中的孔的孔径更大(现有的聚合物隔膜的多孔极性聚合物粘结层中的孔径通常为0.5μm-1μm，根据本公开的聚合物隔膜的多孔极性聚合物粘结层中的孔径为3μm以上，通常为3-10μm，如3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm)，多孔极性聚合物粘结层为多层丝网交织结构，所述亲水性阻滞层的部分表面通过所述多层丝网交织结构而暴露可见；然而现有的聚合物隔膜中的多孔极性聚合物粘结层更为致密，呈蜂窝状。
根据本公开的第四个方面，本公开提供了本公开第一个方面或者第三个方面所述的聚合物隔膜在锂离子电池中的应用。将该聚合物薄膜用于锂离子电池，能与锂离子电池的正极极片和负极极片牢固地粘结在一起，与正极极片和负极极片的结合力强，使得锂离子电池具有较高的硬度，同时不会引起电池性能减弱或对电池产生其他不利影响，锂离子电池的电性能较佳，且安全性较好。
根据本公开的第五个方面，本公开提供了一种锂离子电池，所述锂离子电池包括正极极片、负极极片、以及聚合物隔膜，其中，聚合物隔膜为本公开第一个方面或者第三个方面所述的聚合物隔膜。该锂离子电池中聚合物隔膜可以与正极极片和负极极片牢固的结合在一起，硬度较高，且电性能较佳，安全性较好。
根据本公开的锂离子电池，所述正极极片是由用于锂离子电池的正极材料、导电剂和粘结剂调成浆料涂布于铝箔上制成。所用的正极材料包括任意可用于锂离子电池的正极材料，例如，氧化钴锂(LiCoO 2)、氧化镍锂(LiNiO 2)、氧化锰锂(LiMn 2O 4)和磷酸亚铁锂(LiFePO 4)中的一种或两种以上。所述负极极片是由用于锂离子电池的负极材料、导电剂和粘结剂调成浆料涂布于铜箔上制成。所用负极材料包括任意可用于锂离子电池的负极材料，例如，石墨、软碳、硬碳中的一种或两种以上。
根据本公开的锂离子电池，可以含有电解液，也可以不含有电解液。所述电解液为本领域技术人员公知，含有锂盐和有机溶剂。所述锂盐可以为可离解的锂盐，例如，可以为选自六氟磷酸锂(LiPF 6)、高氯酸锂(LiClO 4)和四氟硼酸锂(LiBF 4)中的一种或两种以上。所述有机溶剂可以为选自碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)和碳酸亚乙烯酯(VC)中的一种或两种以上。一些具体实施例中，所述电解液中，锂盐的浓度可以为0.8-1.5mol/L。
根据本公开的锂离子电池可以采用包括以下步骤的方法制备：
S1、采用本公开第二个方面所述的方法制备聚合物隔膜；
S2、将所述聚合物隔膜设置在正极极片和负极极片之间，形成电池极芯后，进行封装。
步骤S2可以采用锂离子电池制备技术领域的常规方法进行，本公开对此没有特别限定。步骤S2中，可以向电池极芯中灌装电解液，也可以不灌装电解液直接进行封装。
以下结合实施例详细说明本公开，但并不因此限定本公开的范围。
以下实施例和对比例涉及以下测试方法。
(1)面密度采用重量法测定。
(2)亲水性阻滞层和水的接触角采用GB/T30693-2014塑料薄膜与水接触角的测量中规定的方法。
(3)粒径采用激光粒度仪测定，为体积平均粒径。
(4)比表面积采用GB/T 19587-2004气体吸附BET法测定固态物质比表面积中规定的方法。
实施例1-1至1-4用于制备根据本公开的亲水性阻滞层。
实施例1-1
将用气相法制备的亲水性二氧化硅(比表面积为380m 2/g，粒径为80nm，购自阿拉丁)、丙烯酸酯类粘合剂(P1005，购自上海爱高化工有限公司)、分散剂(PVA，购自阿拉丁)、分散剂(PAANa，购自日本昭和电工)、作为增稠剂的羧甲基纤维素(CMC，购自日本大赛璐)以固含量95：5：0.4：0.4：1.5(重量比)分散在水中，控制固含量为8重量％，调节浆液的pH值为8.5，搅拌均匀，形成亲水性阻滞浆液。将亲水性阻滞浆液以凹版辊涂布的方法，涂布至单面陶瓷隔膜(9μmPE+2μm陶瓷层，陶瓷层中的陶瓷颗粒为微米级三氧化二铝陶瓷颗粒，购自山东国瓷，下同)两侧，在55℃干燥12小时，得到具有亲水性阻滞层的隔膜，其中，亲水性阻滞层的厚度为0.5μm，亲水性阻滞层和水的接触角为7°。图1和图2示出了该亲水性阻滞层的SEM形貌图片。
实施例1-2
将用沉淀法制备的亲水性二氧化硅(比表面积为370m 2/g，粒径为150nm，购自阿拉丁)、丙烯酸酯类粘合剂(P1005，购自上海爱高化工有限公司)、分散剂(PVA)、分散剂(PAANa)、增稠剂Latekoll D(购自巴斯夫)以固含量95：8：0.4：0.4：1.0(重量比)分散在水中，控制浆液的固含量为6重量％，调节浆液的pH值为9.6，搅拌均匀，形成亲水性阻滞浆液。将亲水性阻滞浆液以凹版辊涂布的方法，涂布至单面陶瓷隔膜两侧，在50℃干燥14小时，得到具有亲水性阻滞层的隔膜，其中，亲水性阻滞层的厚度为0.7μm，亲水性阻滞层和水的接触角为11°。
实施例1-3
将用气相法制备的亲水性三氧化二铝(比表面积为350m 2/g，粒径为200nm，购自阿拉丁)、丙烯酸酯类粘合剂(P2010，购自上海爱高化工有限公司)、分散剂(PVA)、分散剂(PAANa)、增稠剂Latekoll D(购自巴斯夫)以固含量95：10：0.4：0.4：1.4(重量比)分散在水中，控制浆液的固含量为22重量％，调节浆液的pH值为8.2，搅拌均匀，形成亲水性阻滞浆液。将亲水性阻滞浆液以喷涂的方法，涂布至单面陶瓷隔膜两侧，在50℃干燥8小时，得到具有亲水性阻滞层的隔膜，其中，亲水性阻滞层的厚度为0.6μm，亲水性阻滞层和水的接触角为13°。
实施例1-4
将用气相法制备的亲水性三氧化二铝(比表面积为320m 2/g，粒径为320nm，购自阿拉丁)、丙烯酸酯类粘合剂(P2010，购自上海爱高化工有限公司)、分散剂(PVA)、分散剂(PAANa)、增稠剂Latekoll D(购自巴斯夫)以固含量95：12：0.4：0.4：0.8(重量比)分散在水中，控制浆液的固含量为15重量％，调节浆液的pH为9.5，搅拌均匀，形成亲水性阻滞浆液。将亲水性阻滞浆液以凹版辊涂布的方法，涂布至单面陶瓷隔膜两侧，在50℃干燥12小时，得到具有亲水性阻滞层的隔膜，其中，亲水性阻滞层的厚度为0.8μm，亲水性阻滞层和水的接触角为12°。
以下实施例用于制备根据本公开的聚合物隔膜以及锂离子电池。
实施例2-1A
(1)将P(VDF-HFP)粉末(Kynar powerflex LBG粉末，购自阿科玛，下同)溶解于N,N-二甲基甲酰胺中，控制P(VDF-HFP)的浓度为临界浓度(为10重量％)，搅拌均匀。将搅拌形成的溶液的温度降至20℃，加入干冰，得到极性聚合物粘结剂溶液，其中，相对于100重量份N,N-二甲基甲酰胺，干冰的加入量为1重量份。
将极性聚合物粘结剂溶液以凹版辊涂布的方法，涂布至实施例1-1制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，在45℃鼓风烘干10小时，形成多孔极性聚合物粘结层，从而得到根据本公开的聚合物隔膜。
(2)将LiCoO 2、PVDF粘结剂和炭黑按照质量比100：0.8：0.5调成浆料涂布于铝箔上并烘干制成厚度为0.114mm的LiCoO 2正极极片。
将丁苯橡胶(SBR)和羧甲基纤维素(CMC)分散在水中，与人造石墨、导电剂按照质量比为2.5：1.5：90：6在室温(25℃)高速搅拌3.5小时，将搅拌好的材料涂于铜箔上并烘干制成厚度为0.135mm的石墨负极极片。
(3)在干燥房中，将LiCoO 2正极极片、石墨负极极片和步骤(2)制备的聚合物隔膜以卷绕的方式制备CSL454187型LiCoO 2/石墨软包锂离子电池极芯，灌装电解液后进行封装得到锂离子电池；其中，原陶瓷面朝向正极，电解液中的电解质为六氟磷酸锂，其浓度为1mol/L，有机溶剂为EC、EMC和DEC按重量比1：1：1混合得到的混合液。
实施例2-1B
实施例2-1B采用与实施例2-1A相同的方法制备锂离子电池，不同的是，步骤(1)中，将极性聚合物粘结剂溶液以浸入涂布法，涂布至实施例1-3制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，其中，将具有亲水性阻滞层的隔膜浸入极性聚合物粘结剂溶液中，浸渍时间为30秒。
实施例2-2A
实施例2-2A采用与实施例2-1A相同的方法制备锂离子电池，不同的是，采用以下方法制备聚合物隔膜：将P(VDF-HFP)粉末溶解于N-甲基吡咯烷酮中，控制P(VDF-HFP)的浓度为临界浓度(为12重量％)，搅拌均匀。将搅拌形成的溶液的温度降至20℃，加入干冰，得到极性聚合物粘结剂溶液，其中，相对于100重量份N-甲基吡咯烷酮，干冰的加入量为1.5重量份。将极性聚合物粘结剂溶液以凹版辊涂布的方法，分别涂布至实施例1-2制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，在35℃鼓风烘干24小时，形成多孔极性聚合物粘结层，从而得到根据本公开的聚合物隔膜。
实施例2-2B
实施例2-2B采用与实施例2-2A相同的方法制备锂离子电池，不同的是，步骤(1)中，将极性聚合物粘结剂溶液以浸入涂布法，涂布至实施例1-4制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，其中，将具有亲水性阻滞层的隔膜浸入极性聚合物粘结剂溶液中，浸渍时间为30秒。
实施例2-3A
实施例2-3A采用与实施例2-1A相同的方法制备锂离子电池，不同的是，采用以下方法制备聚合物隔膜：将P(VDF-HFP)粉末溶解于磷酸三乙酯中，控制P(VDF-HFP)的浓度为临界浓度(为12重量％)，搅拌均匀。将搅拌形成的溶液的温度降至20℃，加入干冰，得到极性聚合物粘结剂溶液，其中，相对于100重量份磷酸三乙酯，干冰的加入量为1.8重量份。将极性聚合物粘结剂溶液以凹版辊涂布的方法，涂布至实施例1-2制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，在30℃鼓风烘干24小时，形成多孔极性聚合物粘结层，从而得到根据本公开的聚合物隔膜。
实施例2-3B
实施例2-3B采用与实施例2-3A相同的方法制备锂离子电池，不同的是，步骤(1)中，将极性聚合物粘结剂溶液以浸入涂布法，涂布至实施例1-3制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面，其中，将具有亲水性阻滞层的隔膜浸入极性聚合物粘结剂溶液中，浸渍时间为30秒。
对比例1
采用与实施例2-1A相同的方法制备聚合物隔膜和锂离子电池，不同的是，步骤(1)中，具有亲水性阻滞层的隔膜用实施例1-1中的单面陶瓷隔膜(9μmPE+2μm陶瓷层)代替，即极性聚合物粘结剂溶液直接涂布至单面陶瓷隔膜两侧表面，并且N,N-二甲基甲酰胺用等重量的丙酮代替，得到聚合物隔膜(该聚合物隔膜不具有亲水性阻滞层)。
对比例2
采用与实施例2-3B相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备聚合物隔膜时，具有亲水性阻滞层的隔膜用实施例1-3中的单面陶瓷隔膜(9μmPE+2μm陶瓷层)代替，即极性聚合物粘结剂溶液直接涂布至单面陶瓷隔膜两侧表面，并且磷酸三乙酯用等重量的丙酮代替，得到聚合物隔膜(该聚合物隔膜不具有亲水性阻滞层)。
对比例3
采用与实施例2-1A相同的方法制备聚合物隔膜和锂离子电池，不同的是，极性聚合物粘结剂溶液不含干冰。
对比例4
采用与实施例2-1A相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备聚合物隔膜时，具有亲水性阻滞层的隔膜用实施例1-3中的单面陶瓷隔膜(9μmPE+2μm陶瓷层)代替，即极性聚合物粘结剂溶液直接涂布至单面陶瓷隔膜两侧表面，得到聚合物隔膜(该聚合物隔膜不具有亲水性阻滞层)。
实施例3
采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，步骤(1)中，不是在35℃鼓风烘干20小时，而是在120℃鼓风烘干8小时。
实施例4
采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备极性聚合物粘结剂溶液时，控制P(VDF-HFP)的浓度为4重量％(非临界浓度)。
实施例5
采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备极性聚合物粘结剂溶液时，控制P(VDF-HFP)的浓度为22重量％(非临界浓度)。
实施例6
采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备极性聚合物粘结剂溶液时，N,N-二甲基甲酰胺用等重量的丙酮代替。
实施例7
采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，在制备极性聚合物粘结剂溶液时，N,N-二甲基甲酰胺用等重量的丙酮和N,N-二甲基酰胺的混合液代替，所述混合液中，丙酮与N,N-二甲基甲酰胺的重量比为1：1。
实施例8
采用与实施例1-1相同的方法制备具有亲水性阻滞层的隔膜，不同的是，步骤(1)中，气相法亲水性二氧化硅用石英(比表面积为10m 2/g，粒径为10μm)代替，从而得到具有亲水性阻滞层的隔膜，形成的亲 水性阻滞层和水的接触角为38°；采用与实施例2-1A相同的方法制备聚合物隔膜和锂离子电池，不同的是，采用实施例8制备的具有亲水性阻滞层的隔膜。
实施例9
采用与实施例1-3相同的方法制备具有亲水性阻滞层的隔膜，不同的是，气相法亲水性三氧化二铝用醇铝法三氧化二铝(比表面积为130m 2/g，粒径为5μm)代替，从而得到具有亲水性阻滞层的隔膜，形成的亲水性阻滞层和水的接触角为32°；采用与实施例2-1B相同的方法制备聚合物隔膜和锂离子电池，不同的是，采用实施例9制备的具有亲水性阻滞层的隔膜。
实施例10
实施例10采用与实施例2-1B相同的方法制备锂离子电池，不同的是，步骤(1)中，将极性聚合物粘结剂溶液以喷涂涂布法，涂布至实施例1-3制备的具有亲水性阻滞层的隔膜两侧的亲水性阻滞层表面。
实施例11
采用与实施例10相同的方法制备聚合物隔膜和锂离子电池，不同的是，采用与实施例10相同的方法将亲水性阻滞浆液涂布在单面陶瓷隔膜两侧之后不进行烘干，而是直接采用实施例10的方法喷涂极性聚合物粘结剂溶液后，采用与实施例10相同的方法进行烘干，从而得到聚合物隔膜。
测试例
(1)聚合物隔膜表面形貌的观察：
采用扫描电子显微镜(SEM，JEOL，JSM-7600FE)观察各实施例和对比例制备的聚合物隔膜的微观形貌。
图3和图4示出了实施例2-1A制备的聚合物隔膜的SEM形貌照片，图5和图6示出了实施例2-1B制备的聚合物隔膜的SEM形貌照片。
由图3、图4、图5和图6可以看出，采用本公开的方法能制备多孔性颇佳的多孔极性聚合物粘结层，同时制备的多孔极性聚合物粘结层的表面具有多孔膜层。图7和图8示出了对比例1制备的聚合物隔膜的SEM形貌照片，图9和图10示出了对比例3制备的聚合物隔膜的SEM形貌照片。
将图3和图4与图7和图8进行比较可以看出，根据本公开的聚合物隔膜表面的多孔极性聚合物粘结层中的孔包括具有第一孔径的孔和具有第二孔径的孔，所述第一孔径为5-20μm，所述第二孔径为200nm-2μm，所述亲水性阻滞层的部分表面通过所述多层丝网交织结构而暴露可见；对比例1制备的聚合物隔膜中的多孔极性聚合物粘结层则较为致密，呈蜂窝状。
将图3和图4与图9和10进行比较可以看出，采用本公开的方法制备的聚合物隔膜的多孔极性聚合物粘结层中的孔包括具有第一孔径的孔和具有第二孔径的孔，所述第一孔径为5-20μm，所述第二孔径为200nm-2μm。
(2)聚合物隔膜透气性(Gurley值)和表观孔隙率测试
采用型号为Gurley 4110N的透气度仪进行测试。测试100mL空气在1标准大气压下通过面积为1.0平方英寸的聚合物隔膜的时间。
聚合物隔膜的透气性的测试结果列于表1。
由表1的结果可以看出，根据本公开的聚合物隔膜显示出较好的透气性。
聚合物隔膜的表观孔隙率根据如下公式计算得到：
Figure PCTCN2019084568-appb-000001
上式中，ρM为表观密度，ρf为面密度，ρP为体密度，d为聚合物隔膜的厚度。
由表1的数据可以看出，根据本公开的聚合物隔膜具有较高的表观孔隙率。
(3)聚合物隔膜热收缩率测试
在90℃和120℃温度下分别利用恒温烘箱对聚合物隔膜(面积为5mm×5mm)进行等温热处理2h和1h，表征聚合物隔膜的耐温性能。
实验结果在表1中列出，由表1的结果可知，根据本公开的聚合物隔膜具有较低的热收缩率。
(4)聚合物隔膜拉伸强度测试
根据GB/T 13022-1991中规定的方法，使用万能力学试验机测定。
实验结果在表1中列出，由表1的结果可知，根据本公开的聚合物隔膜具有较高的拉伸强度。
(5)聚合物隔膜穿刺强度测试
根据GB/T 1004-2008中规定的方法，使用万能力学试验机测定，钢针直径为1毫米。
实验结果在表1中列出，由表1可知，根据本公开的聚合物隔膜具有较高的穿刺强度。
表1
Figure PCTCN2019084568-appb-000002
Figure PCTCN2019084568-appb-000003
1：聚合物隔膜的厚度   2：极性聚合物涂层分别在聚合物隔膜两个表面的单面面密度
(6)聚合物隔膜离子电导率测试
采用交流阻抗法测试，具体操作步骤如下。
聚合物隔膜裁成直径为17mm的圆片，烘干后，重叠三层，放在两个不锈钢(SS)电极之间，吸收足量电解液(电解质为六氟磷酸锂，其浓度为1mol/L，有机溶剂为EC、EMC和DEC按重量比1：1：1混合得到的混合液)，密封于2016型扣式电池中，采用电化学工作站(上海辰华，CHI 660C)进行交流阻抗实验，交流信号频率范围为0.01Hz至1MHz，正弦波电位幅值为5mV，线性与实轴的交点即为聚合物隔膜的本体电阻，采用以下公式计算得到聚合物隔膜的离子电导率：
σ＝L/(A·R)，
其中，L表示凝胶聚合物电解质的厚度，
A为不锈钢板与聚合物隔膜的接触面积，
R为聚合物电解质的本体阻抗。
本体阻抗和聚合物隔膜的离子电导率列于表2。
由表2可知，根据本公开的聚合物隔膜显示出优异的离子电导率。
表2
Figure PCTCN2019084568-appb-000004
Figure PCTCN2019084568-appb-000005
(7)聚合物隔膜对正负极粘性与剥离强度测试
将制备的锂离子电池(经过85℃，4h，1MPa热压)在满电态下进行解剖，采用万能力学试验机测定其剥离力学强度，测定标准参照GBT 2792-2014胶粘带剥离强度的试验方法；并对所得到的正负极极片和隔膜进行拍照。图11和图12以及图13和图14分别给出了实施例2-1A制备的锂离子电池的正极和负极与聚合物隔膜剥离后的SEM形貌照片，图15和图17分别示出了实施例2-1A制备的锂离子电池的正极和负极的剥离强度测试曲线图，图16和图18分别示出了对比例1制备的锂离子电池的正极和负极的剥离强度测试曲线图作为对比。
由图11和图12以及图113和图14可知：采用本公开的聚合物隔膜制备的锂离子电池进行剥离后，聚合物隔膜的多孔极性聚合物粘结层均黏在正极材料上；部分负极料粘在聚合物隔膜上。
由图17和图18可以看出，根据本公开的聚合物隔膜对锂离子电池的正极和负极均具有较高的粘性。
(8)锂离子电池硬度测试
测试结果在表3中列出。如表3所示，根据本公开的锂离子电池具有较高的硬度。
表3
Figure PCTCN2019084568-appb-000006
(9)电池常温循环性能测试
采用(广州兰奇，BK6016)锂离子电池性能测试柜，对实施例和对比例制备得到的分容后的锂离子电池进行25℃循环性能测试，具体方法如下。
将电池分别以0.7C、0.2C充电至4.40V截止；搁置10min，以0.7C或0.2C放至3.0V，如此循环。表4的测试结果表明：根据本公开的锂离子电池显示出更为优异的循环性能。
表4
Figure PCTCN2019084568-appb-000007
(10)电池高温循环性能测试
采用(广州兰奇，BK6016)锂离子电池性能测试柜，对实施例和对比例得到的分容后的锂离子电池，进行45℃循环性能的测试。测试方法为：将电池以0.7C充电至4.40V截止；搁置10min，以0.7C放至3.0V，如此循环。循环结果见表5。
测试结果表明：根据本公开的锂离子电池显示出更为优异的高温循环性能。由此可见，根据本公开的聚合物隔膜有利于提高电池的高温性能。
表5
Figure PCTCN2019084568-appb-000008
Figure PCTCN2019084568-appb-000009
(11)电池倍率性能测试
采用(广州兰奇，BK6016)锂离子电池性能测试柜，对实施例和对比例得到的分容后的锂离子电池进行倍率放电性能测试。具体测试方法如下。
将电池用0.5C(1C＝2640mA)恒流恒压充电至4.40V，截止电流为0.02C，搁置5min，用0.2C/0.5C/1C/2C/3C/4C放电至3.0V，记录放电容量。
倍率放电测试结果列于表6。测试结果表明，根据本公开的锂离子电池显示出良好的倍率放电性能。
表6
Figure PCTCN2019084568-appb-000010
Figure PCTCN2019084568-appb-000011
(12)电池高温储存性能测试
对实施例和对比例得到的锂离子电池进行85℃4h储存性能测试。测试方法如下。
1)采用(广州兰奇，BK6016)锂离子电池性能测试柜将电池以0.5C充电至4.40V，0.02C截止；搁置5min，以0.2C放电至3.0V，记录前放电容量；
2)将电池以0.5C充电至4.40V，0.02C截止；搁置1h后测试前电压、内阻、厚度；
3)将电池放入85℃烤箱储存4h；
4)储存后测试立即厚度，常温放置2h后测试冷却厚度、后电压、后内阻；
5)将电池以0.2C放电至3.0V；
6)以0.5C充满电，搁置5min，以0.2C放电至3.0V，记录恢复容量，并计算容量恢复率(恢复容量除以前容量)。
测试结果见表7。由表7可知：根据本公开的锂离子电池高温储存后在容量保持率和容量恢复率均更好。由此可见，根据本公开的聚合物隔膜有利于提高电池的高温性能。
表7
编号 恢复容量(mAh) 容量恢复率(％)
实施例2-1A 2587 98.0
实施例2-1B 2573 97.5
实施例2-2A 2575 97.6
实施例2-2B 2576 97.6
实施例2-3A 2582 97.8
实施例2-3B 2581 97.7
对比例1 2267 87.2
对比例2 2281 89.7
对比例3 2283 89.8
对比例4 2151 81.5
实施例3 2314 87.7
实施例4 2217 84.0
实施例5 2236 84.7
实施例6 2573 97.5
实施例7 2577 97.6
实施例8 2202 83.4
实施例9 2237 84.7
实施例10 2252 85.3
实施例11 2224 84.2
将实施例2-1A与对比例1和对比例4进行比较、将实施例2-3B与对比例2进行比较，可以看出，通过设置亲水性阻滞层，即便采用高沸点溶剂配制极性聚合物溶液，制备的锂离子电池也具有良好的倍率放电性能，特别是在大倍率放电条件下显示出明显提高的放电性能。
将实施例2-1B与实施例3进行比较可以看出，将极性聚合物粘结剂涂层在不高于60℃的温度下进行干燥，能显著提高制备的聚合物隔膜的透气性和离子电导率，明显提高最终制备的锂离子电池的各项性能。将实施例2-1B与实施例4和5进行比较可以看出，控制极性聚合物粘结剂溶液中极性聚合物的浓度为临界浓度，能显著提高制备的聚合物隔膜的透气性和离子电导率，明显提高最终制备的锂离子电池的各项性能。将实施例2-1A和实施例2-1B分别与实施例8和9进行比较可以看出，使得亲水性阻滞层与水的接触角为不高于20°能进一步提高最终制备的锂离子电池的各项性能。将实施例10与实施例11进行比较可以看出，将亲水性阻滞涂层干燥后涂布极性聚合物粘结剂溶液，形成极性聚合物粘结层，能进一步提高制备的聚合物隔膜的透气性和离子电导率，从而提高最终制备的锂离子电池的各项性能。
以上详细描述了本公开的一些具体实施方式，但是，本公开并不限于此。在本公开的技术构思范围内，可以对本公开的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本公开所公开的内容，均属于本公开的保护范围。

Claims (20)

  1. 一种聚合物隔膜，该聚合物隔膜含有：
    多孔基材；
    亲水性阻滞层，所述亲水性阻滞层设置在所述多孔基材的一个表面或者相对的两个表面上；以及
    多孔极性聚合物粘结层，所述多孔极性聚合物粘结层设置在所述亲水性阻滞层远离所述多孔基材的表面上，所述多孔极性聚合物粘结层的孔径200nm-20μm。
  2. 根据权利要求1所述的聚合物隔膜，其中，所述多孔极性聚合物粘结层中的孔包括具有第一孔径的孔和具有第二孔径的孔，所述第一孔径为5-20μm，所述第二孔径为200nm-2μm；
    或者，所述第一孔径为5-10μm，所述第二孔径为200nm-2μm。
  3. 根据权利要求1或2所述的聚合物隔膜，其中，所述多孔极性聚合物粘结层的孔隙率为20-80％。
  4. 根据权利要求1-3中任意一项所述的聚合物隔膜，其中，所述多孔极性聚合物粘结层包括贯通多孔极性聚合物粘结层的通孔。
  5. 根据权利要求1-4中任意一项所述的聚合物隔膜，其中，所述亲水性阻滞层的水接触角为40°以下、20°以下或者2-18°。
  6. 根据权利要求1-5中任意一项所述的聚合物隔膜，其中，所述亲水性阻滞层含有粘合剂以及亲水性无机颗粒，所述亲水性无机颗粒通过所述粘合剂相互粘合；所述亲水性无机颗粒为亲水性Al 2O 3颗粒、亲水性SiO 2颗粒、亲水性SnO 2颗粒、亲水性ZrO 2颗粒、亲水性TiO 2颗粒、亲水性SiC颗粒、亲水性Si 3N 4颗粒、亲水性CaO颗粒、亲水性MgO颗粒、亲水性ZnO颗粒、亲水性BaTiO 3颗粒、亲水性LiAlO 2颗粒和亲水性BaSO 4颗粒中的一种或两种以上。
  7. 根据权利要求6所述的聚合物隔膜，其中，所述亲水性无机颗粒的粒径为1nm至10μm、1nm至5μm、1nm至2μm、10nm至1μm、20nm至800nm或者50nm至350nm；所述亲水性无机颗粒的比表面积为10-600m 2/g、100-500m 2/g或者150-400m 2/g。
  8. 根据权利要求6或7所述的聚合物隔膜，其中，以所述亲水性阻滞层的总量为基准，所述亲水性颗粒的含量为50-95重量％、70-95重量％或者80-95重量％。
  9. 根据权利要求1-8中任意一项所述的聚合物隔膜，其中，所述亲水性阻滞层的厚度为0.1-3μm、0.1-1μm或者0.3-0.8μm。
  10. 根据权利要求1-9中任意一项所述的聚合物隔膜，其中，所述多孔极性聚合物粘结层含有极性聚合物，所述极性聚合物为聚偏氟乙烯、偏氟乙烯-六氟丙烯共聚物以及偏氟乙烯-丙烯酸酯共聚物中的一种或两种以上；所述多孔极性聚合物粘结层的厚度为0.1-10μm、0.2-5μm、0.7-3μm或者0.8-1.5μm。
  11. 根据权利要求1-10中任意一项所述的聚合物隔膜，其中，所述多孔基材含有多孔聚合物层和陶瓷层，所述多孔基材满足以下条件中的一个或两个：
    所述陶瓷层设置在所述多孔聚合物层和所述亲水性阻滞层之间；
    所述多孔聚合物层设置在所述陶瓷层和所述亲水性阻滞层之间。
  12. 根据权利要求11所述的聚合物隔膜，其中，所述陶瓷层的厚度为1-5μm或者1.5-3μm。
  13. 根据权利要求1-12中任意一项所述的聚合物隔膜，其中，所述聚合物隔膜的Gurley值为100-900Sec/100mL、120-600Sec/100mL、120-500Sec/100mL或者150-350Sec/100mL。
  14. 一种聚合物隔膜的制备方法，该方法包括：
    将亲水性阻滞浆液涂布在多孔基材的至少一个表面上形成亲水性阻滞涂层，将所述亲水性阻滞涂层干燥，在所述多孔基材的表面形成亲水性阻滞层；
    将极性聚合物粘结剂溶液涂布在所述亲水性阻滞层远离所述多孔基材的表面上，形成极性聚合物粘结剂涂层，将所述极性聚合物粘结剂涂层进行干燥，在所述亲水性阻滞层表面形成多孔极性聚合物粘结层；
    或者，将所述亲水性阻滞浆液涂布在所述多孔基材的至少一个表面形成所述亲水性阻滞涂层，将所述极性聚合物粘结剂溶液涂布在所述亲水性阻滞涂层远离所述多孔基材的表面上形成所述极性聚合物粘结剂涂层，将所述亲水性阻滞涂层和所述极性聚合物粘结剂涂层进行干燥，在所述多孔基材表面形成所述亲水性阻滞层以及在所述亲水性阻滞层表面形成所述多孔极性聚合物粘结层；
    其中，所述亲水性阻滞浆液含有分散介质、以及分散在所述分散介质中的亲水性无机颗粒以及粘合剂，所述极性聚合物粘结剂溶液含有有机溶剂以及分散在所述有机溶剂中的极性聚合物和造孔剂。
  15. 根据权利要求14所述的方法，其中，所述造孔剂为在将所述极性聚合物粘结剂涂层干燥条件下能形成挥发性气体的物质。
  16. 根据权利要求14或15所述的方法，其中，相对于100重量份所述亲水性无机颗粒，所述粘合剂的含量为1-30重量份。
  17. 根据权利要求14-16中任意一项所述的方法，其中，所述极性聚合物粘结剂溶液中，所述极性聚合物的浓度为1-30重量％、2-25重量％、5-20重量％或者为临界浓度。
  18. 根据权利要求14-17中任意一项所述的方法，其中，所述有机溶剂包括第一有机溶剂和第二有机溶剂中的至少一种，
    所述第一有机溶剂的沸点低于60℃，所述第一有机溶剂包括丙酮；
    所述第二有机溶剂的沸点为60-260℃、120℃以上、140℃以上或者150-230℃，所述第二有机溶剂包括磷酸三乙酯、N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺和二甲基亚砜中的一种或两种以上。
  19. 根据权利要求14-18中任意一项所述的方法，其中，所述干燥在不高于120℃的温度下进行、在不高于60℃的温度下进行或者在20-55℃的温度下进行，所述干燥的持续时间为0.1-36小时。
  20. 一种锂离子电池，所述锂离子电池包括正极极片、负极极片以及聚合物隔膜，所述聚合物隔膜为权利要求1-13中任意一项所述的聚合物隔膜。
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