WO2016161920A1 - 复合隔膜及其制备方法以及锂离子电池 - Google Patents

复合隔膜及其制备方法以及锂离子电池 Download PDF

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WO2016161920A1
WO2016161920A1 PCT/CN2016/078395 CN2016078395W WO2016161920A1 WO 2016161920 A1 WO2016161920 A1 WO 2016161920A1 CN 2016078395 W CN2016078395 W CN 2016078395W WO 2016161920 A1 WO2016161920 A1 WO 2016161920A1
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composite
lithium
gel
barium sulfate
separator
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PCT/CN2016/078395
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English (en)
French (fr)
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尚玉明
丁小磊
何向明
王莉
王要武
李建军
高剑
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江苏华东锂电技术研究院有限公司
清华大学
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Publication of WO2016161920A1 publication Critical patent/WO2016161920A1/zh
Priority to US15/726,385 priority Critical patent/US20180034029A1/en

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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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H01M50/406—Moulding; Embossing; Cutting
    • 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
    • H01M50/417—Polyolefins
    • 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
    • H01M50/42—Acrylic resins
    • 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
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • H01M50/489—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
    • H01M50/497—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 invention relates to a composite separator for a lithium ion battery, a method of preparing the same, and a lithium ion battery using the composite separator.
  • a gel electrolyte also called a gel polymer electrolyte, is a composite of a polymer and an electrolyte, and the electrolyte is encapsulated in a network formed by the polymer to form a gel.
  • Lithium ion batteries using gel polymer electrolytes are commonly known as gel polymer batteries.
  • gel polymer electrolytes Compared with traditional liquid electrolytes, gel polymer electrolytes have the advantages of not easy to leak, high flexibility, high physical and chemical stability, but also have some disadvantages, such as low mechanical strength, low ion conductivity, and charge and discharge of batteries. There is a certain gap between the rate performance and the liquid electrolyte battery, so its application is mostly limited to the field of digital batteries used in low magnification. In the field of power batteries, it is still necessary to improve the electrical properties of the gel polymer electrolyte charge and discharge ratio.
  • the researchers doped nano-ceramic particles (such as TiO 2 nanoparticles, SiO 2 nanoparticles, Al 2 O 3 nanoparticles, etc.) in the gel polymer electrolyte to prepare composite gel electrolytes, using nanoparticles.
  • nano-ceramic particles such as TiO 2 nanoparticles, SiO 2 nanoparticles, Al 2 O 3 nanoparticles, etc.
  • the complexing effect and large specific surface effect form a fast ion transport channel at the organic-inorganic interface, which can improve the ion conductivity of the gel electrolyte and improve the rate performance and cycle stability of the battery.
  • the particles due to the low zeta potential of the nano ceramic particles and the high surface energy, the particles are easily agglomerated, and the agglomerated nanoparticles hardly exert the characteristics possessed by the nanomaterial itself.
  • a composite separator comprising a separator substrate and a composite gel composited with the separator substrate, the composite gel comprising a gel polymer and a nanometer surface-modified lithium carboxylate group dispersed in the gel polymer Barium sulfate.
  • a method for preparing a composite separator comprising: adding a solution in which a lithium carboxylate is dissolved in an organic solvent to a soluble cerium salt aqueous solution, mixing to form a first solution; providing a soluble sulfate aqueous solution having a pH of 8-10, the soluble solution An aqueous solution of sulphate is added to the first solution to form a precipitate; the precipitate is separated, washed with water and dried to obtain nano strontium sulfate having a surface modified with a lithium carboxylate group; the surface is modified with a lithium carboxylate group The nano-barium sulfate is dispersed in an organic solvent to form a dispersion; a gel polymer is added to the dispersion, uniformly mixed to obtain the composite gel; and the composite gel is combined with a separator substrate to obtain the composite separator.
  • a lithium ion battery comprising a positive electrode, a negative electrode, and a gel polymer electrolyte membrane disposed between the positive electrode and the negative electrode, the gel polymer electrolyte membrane comprising the composite membrane, and non-water permeating the composite membrane Electrolyte.
  • the present invention prepares a highly dispersible nano-barium sulfate particle surface-modified with a lithium carboxylate group, which on the one hand makes the nano-barium sulfate easy to uniformly disperse, on the other hand, changes The zeta potential of nano-barium sulfate reduces surface energy.
  • the nano-barium sulfate particles are used as doping particles and uniformly mixed with the gel polymer matrix, the nano-barium sulfate can be uniformly dispersed in the gel polymer, and the lithium carboxylate group can promote the transport of lithium ions and increase the ions.
  • Conductivity, which makes lithium-ion batteries have higher rate performance.
  • Example 1 is a scanning electron micrograph of nano-barium sulfate according to Example 1 of the present invention.
  • Example 2 is a scanning electron micrograph of a composite separator of Example 4 of the present invention.
  • Example 3 is a cycle performance curve of lithium ion batteries of Example 4 and Comparative Example 2 at different current rates.
  • Embodiments of the present invention provide a method for preparing a composite separator, which includes the following steps:
  • the composite gel is combined with a separator substrate to obtain a composite separator.
  • the step S1 includes:
  • the lithium carboxylate forms a stable lithium ruthenium carboxylate complex with the soluble bismuth salt of Ba 2+ , and the complex slowly releases Ba 2 during the subsequent precipitation of barium sulfate.
  • the effect of + is such that the barium sulfate particles do not grow too large to form nano barium sulfate.
  • the nanometer barium sulfate surface is modified with a lithium carboxylate group, so that the nano barium sulfate particles are not easily agglomerated, and is favorable for secondary dispersion in subsequent applications;
  • the lithium carboxylate group can increase the concentration of ions on the surface of the nano-barium sulfate particles and promote the transport of lithium ions in the separator.
  • the lithium carboxylate has at least 8 carbon atoms.
  • the lithium carboxylate may be lithium oleate, lithium stearate, lithium lauryl benzoate, lithium cetyl benzoate or lithium polyacrylate.
  • the mass of the lithium carboxylate is preferably from 1% to 5% by mass of the subsequently theoretically formed nanometer barium sulfate.
  • the organic solvent is capable of dissolving lithium carboxylate and forming mesopores inside the barium sulfate particles during subsequent formation of barium sulfate.
  • the organic solvent is a polar water-soluble organic solvent, and may be methanol, ethanol, isopropanol, acetone, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) or N.
  • a polar water-soluble organic solvent such as methylpyrrolidone (NMP), preferably an alcoholic organic solvent such as ethanol, methanol or isopropanol.
  • the volume ratio of the organic solvent to the soluble hydrazine salt aqueous solution is from 1:1 to 2:1, preferably 1:1.
  • the concentration of the soluble cerium salt aqueous solution is in the range of 0.1 mol/L to 0.5 mol/L, and the soluble cerium salt is a commonly used soluble cerium salt such as cerium chloride, cerium nitrate or strontium sulfide.
  • the soluble sulfate is slowly added to the first solution, and the soluble sulfate SO 4 2- forms a nano-sized barium sulfate with the slowly released Ba 2+ in the first solution, and the nano-barium sulfate surface modification It has a lithium carboxylate group and contains mesopores inside.
  • the soluble sulfate may be a commonly used soluble sulfate such as sodium sulfate, potassium sulfate, ammonium sulfate or aluminum sulfate.
  • the concentration of the aqueous solution of the soluble sulfate is in the range of 0.1 mol/L to 0.5 mol/L.
  • the molar ratio of the soluble sulfate to the soluble cerium salt is 1:1.
  • the aqueous solution of the soluble sulfate is adjusted by an alkaline solution such as ammonia water, sodium hydroxide or potassium hydroxide to have a pH of preferably 8 to 10.
  • the precipitate is centrifuged from the solution, washed with water for 3-4 times and vacuum dried to obtain nano-barium sulfate having a surface modified with a lithium carboxylate group, and the particle size ranges from 30 nm to 500 nm.
  • the specific surface area is 5 m 2 /g to 20 m 2 /g.
  • Each nanometer barium sulfate particle contains mesopores, and the pore diameter of the mesopores ranges from 6 nm to 10 nm.
  • the reaction temperature of the entire process is preferably from 15 ° C to 45 ° C.
  • the preparation of the composite gel in the step S2 comprises:
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group is added to the organic solvent and then dispersed by mechanical stirring or ultrasonic vibration.
  • the time of stirring and sonication depends on the dispersion, and is preferably 0.5 to 2 hours.
  • the gel polymer is gradually added to the dispersion while stirring the dispersion, and stirring is continued to uniformly mix the dispersion with the gel polymer, thereby modifying the surface with a lithium carboxylate group.
  • the nano-barium sulfate is uniformly dispersed in the gel polymer matrix.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group and a gel polymer can be dispersed in the organic solvent.
  • the organic solvent may be a polar solvent such as one or more of NMP, DMF, DMAc and acetone.
  • the gel polymer is a gel polymer commonly used in gel electrolyte lithium ion batteries, such as polymethyl methacrylate (PMMA), a copolymer of vinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyacrylonitrile. At least one of (PAN) and polyethylene oxide (PEO).
  • the step of combining the composite gel with the membrane substrate in the step S3 may specifically include:
  • step S31 the composite gel of step S2 is attached to the separator substrate to form a composite gel layer;
  • the composite gel may be applied to both sides or one side of the separator substrate by a method such as knife coating, dip coating, extrusion coating or the like.
  • the separator substrate may be taken out after immersing the composite gel, and the composite gel may penetrate into the pores of the separator substrate, and a thin layer having a thickness of 10 ⁇ m or less may be formed on the surface of the separator substrate.
  • the separator substrate may be a polyolefin porous film, and the polyolefin porous film may be a polypropylene porous film, a polyethylene porous film, a polypropylene porous film, or a polypropylene-polyethylene-polypropylene composite porous film.
  • the base film is used to insulate electrons and pass lithium ions through the pores of the porous membrane.
  • the base film can be a commercially available lithium ion battery separator, such as a separator manufactured by Asahi, Tosei, Tobe, Ube, and Celgard. This embodiment employs a Celgard-2325 type separator manufactured by Celgard.
  • the pore former is a poor solvent of the gel polymer, such as water, ethanol, methanol, or a mixed solution thereof, so that the solvent in the composite gel layer can be partially removed from the gel polymer.
  • the pore forming agent is an aqueous ethanol solution (ethanol content of 2 to 20% by weight).
  • the soaking time can be from 0.5 hours to 5 hours.
  • the separator substrate to which the composite gel layer is attached after being taken out of the pore former may be immersed in deionized water.
  • step S33 it is preferably dried at 40 ° C to 60 ° C for 24 hours to 48 hours to obtain a porous composite separator.
  • Embodiments of the present invention provide a composite separator including the separator substrate and a composite gel composited with the separator substrate.
  • the composite gel may be in the form of a layer attached to the surface of the separator substrate.
  • the membrane substrate has pores into which the composite gel can be filled.
  • the thickness of the composite gel layer formed on the surface of the separator substrate is preferably 2 ⁇ m to 10 ⁇ m.
  • the composite gel comprises a gel polymer and nano-barium sulfate having a surface modified with a lithium carboxylate group dispersed in the gel polymer.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group has a particle diameter of about 30 nm to 500 nm, preferably 30 nm to 120 nm.
  • the gel polymer is a gel polymer commonly used in gel electrolyte lithium ion batteries, such as at least one of PMMA, PVDF-HFP, PAN and PEO.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group is uniformly dispersed in the gel polymer.
  • the composite gel may also include an amount of an organic solvent that is compatible with the gel polymer.
  • the organic solvent may be one or more of NMP, DMF, DMAc, and acetone.
  • the composite membrane can be immersed in a non-aqueous electrolyte to form a gel polymer electrolyte membrane.
  • the surface of the nanometer barium sulfate is modified with a lithium carboxylate group, the nanometer barium sulfate is not easy to be agglomerated, and is easy to be uniformly dispersed, and can be uniformly dispersed in the gel polymer in the process of preparing the composite gel without segregation.
  • the nanometer barium sulfate surface group contains lithium ions, which further facilitates the transport of lithium ions in the composite gel.
  • the nanometer barium sulfate contains mesopores inside, and a certain gap is formed between the barium sulfate particles and the particles, so that the porosity of the composite membrane is increased to facilitate the penetration of the electrolyte, and the wettability of the separator is further improved.
  • Embodiments of the present invention provide a lithium ion battery including a positive electrode, a negative electrode, and a gel polymer electrolyte membrane disposed between the positive electrode and the negative electrode, the gel polymer electrolyte membrane including the composite separator, and the composite membrane Non-aqueous electrolyte in the medium.
  • the non-aqueous electrolyte solution comprises a solvent and a lithium salt solute dissolved in a solvent
  • the solvent may be selected from the group consisting of a cyclic carbonate, a chain carbonate, a cyclic ether, a chain ether, a nitrile, and an amide.
  • the lithium salt solute may be selected from lithium chloride (LiCl), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium methanesulfonate (LiCH 3 SO 3 ), lithium trifluoromethanesulfonate (LiCF 3 SO) 3 ) one or more of lithium hexafluoroarsenate (LiAsF 6 ), lithium perchlorate (LiClO 4 ), and lithium bis(oxalate) borate (LiBOB).
  • LiCl lithium chloride
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiCH 3 SO 3 lithium methanesulfonate
  • LiCF 3 SO lithium trifluoromethanesulfonate
  • LiAsF 6 lithium hexafluoroarsenate
  • LiClO 4 lithium perchlorate
  • LiBOB lithium bis
  • the positive electrode may include a positive electrode current collector and a positive electrode material layer for supporting the positive electrode material layer and conducting current, and may be in the form of a foil or a mesh.
  • the material of the cathode current collector may be selected from aluminum, titanium or stainless steel.
  • the positive electrode material layer is disposed on at least one surface of the positive electrode current collector.
  • the positive electrode material layer includes a positive electrode active material, and further optionally includes a conductive agent and a binder. A conductive agent and a binder may be uniformly mixed with the positive electrode active material.
  • the positive electrode active material may be, for example, lithium iron phosphate, spinel lithium manganate, lithium cobaltate or lithium nickelate.
  • the negative electrode may include a negative electrode current collector and a negative electrode material layer for supporting the negative electrode material layer and conducting current, and the shape may be a foil or a mesh.
  • the material of the anode current collector may be selected from copper, nickel or stainless steel.
  • the anode material layer is disposed on at least one surface of the anode current collector.
  • the negative material layer includes a negative active material, and further optionally includes a conductive agent and a binder. A conductive agent and a binder may be uniformly mixed with the anode active material.
  • the negative active material may be graphite, acetylene black, microbead carbon, carbon fiber, carbon nanotube or cracked carbon or the like.
  • a solution prepared by dissolving 0.01 g of lithium oleate in 50 ml of anhydrous methanol is added to 50 ml of a 0.5 mol/L barium chloride solution, and uniformly mixed for 20 minutes to 30 minutes to form a mixed solution; 50 ml, 0.5 mol/
  • the sodium sulfate solution of L is adjusted to a pH of 8 to 9 by aqueous ammonia, and is slowly added to the above mixed solution, and a precipitate is obtained by centrifugation.
  • the precipitate was washed 3 times in deionized water, and finally vacuum dried in a drying oven at 80 ° C to obtain nano barium sulfate having a surface modified with a lithium carboxylate group.
  • the nanometer barium sulfate particles have a small particle size of about 30 nm to 50 nm, and the nano barium sulfate particles form a certain gap with the particles, and each nanometer barium sulfate particle contains mesopores inside.
  • the mesopore pore size is from 6 nm to 10 nm.
  • the nanometer barium sulfate has a specific surface area of about 19.9 m 2 /g.
  • a solution formed by dissolving 0.02 g of lithium stearate in 100 ml of N,N-dimethylformamide is added to 100 ml of a 0.5 mol/L lanthanum nitrate solution, and uniformly mixed for 20 minutes to 30 minutes to form a mixed solution; 100 ml of a 0.5 mol/L potassium sulfate solution was adjusted to a pH of 8 to 9 with a dilute sodium hydroxide solution, and slowly added to the above mixed solution, and a precipitate was obtained by centrifugation.
  • the precipitate was washed 3 to 4 times in deionized water, and finally dried in a vacuum oven at 80 ° C to obtain nano-barium sulfate having a surface modified with a lithium carboxylate group.
  • the nanometer barium sulfate has a particle diameter of 50 nm to 80 nm.
  • a solution prepared by dissolving 0.03 g of lithium polyacrylate in 150 ml of acetone was added to 150 ml of a 0.5 mol/L barium chloride solution, and uniformly mixed for 20 minutes to 30 minutes to form a mixed solution; 150 ml, 0.5 mol/L
  • the ammonium sulfate solution was adjusted to a pH of 8 to 9 with a dilute potassium hydroxide solution, and slowly added to the above mixed solution, and a precipitate was obtained by centrifugation.
  • the precipitate was washed 3 times in deionized water, and finally vacuum dried in a drying oven at 80 ° C to obtain nano barium sulfate having a surface modified with a lithium carboxylate group.
  • the nanometer barium sulfate has a particle diameter of 80 nm to 120 nm.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group prepared in Example 1 was dispersed in acetone to form a dispersion, and PVDF-HFP was added thereto, and stirred and dissolved to prepare a composite gel liquid.
  • the mass ratio of nano-barium sulfate and PVDF-HFP having a surface modified with a lithium carboxylate group was 0.2:1.
  • the total content of PVDF-HFP and nano-barium sulfate having a surface modified with a lithium carboxylate group in the composite gel solution was 10% by weight.
  • the polypropylene separator was immersed in the composite gel solution, taken out after 5 minutes, then immersed in water, taken out after 30 minutes, and finally vacuum dried in an oven at 80 ° C for 24 hours to obtain a composite separator.
  • a large number of micropores are present on the surface of the composite membrane, and the composite gel is evenly distributed on the surface of the membrane substrate, and no nanometer barium sulfate agglomerated particles are observed.
  • the composite separator was immersed in an electrolytic solution containing 1.0 M of LiPF 6 and a mixed solvent of EC and DEC in a volume ratio of 1:1. Soaking for 5 minutes allows the composite membrane to fully absorb the electrolyte to form a gel polymer electrolyte membrane.
  • the thickness of the composite separator, the liquid absorption rate, and the ionic conductivity of the gel polymer electrolyte membrane were tested. The results are shown in Table 1.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group prepared in Example 1 was dispersed in N-methylpyrrolidone to form a dispersion, and PMMA was added thereto, followed by stirring to dissolve, thereby preparing a composite gel liquid.
  • the mass ratio of nano-barium sulfate to PMMA having a surface modified with a lithium carboxylate group was 0.2:1.
  • the total content of PMMA in the composite gel solution and nano-barium sulfate having a surface modified with a lithium carboxylate group was 10% by weight.
  • the polypropylene separator was immersed in the composite gel solution, taken out after 5 minutes, then immersed in water, taken out after 30 minutes, and finally vacuum dried in an oven at 80 ° C for 24 hours to obtain a composite separator.
  • a gel polymer electrolyte membrane was prepared by the same method as in Example 4, and the thickness, the liquid absorption rate, and the ionic conductivity of the gel polymer electrolyte membrane were tested. The results are shown in Table 1.
  • the nano-barium sulfate having a surface modified with a lithium carboxylate group prepared in Example 1 was dispersed in N,N-dimethylformamide to form a dispersion, PAN was added thereto, and stirred to dissolve to obtain a composite gel liquid.
  • the mass ratio of nano-barium sulfate and PAN having a surface modified with a lithium carboxylate group was 0.2:1.
  • the total content of PAN in the composite gel solution and nano-barium sulfate having a surface modified with a lithium carboxylate group was 10% by weight.
  • the polypropylene separator was immersed in the composite gel solution, taken out after 5 minutes, then immersed in water, taken out after 30 minutes, and finally vacuum dried in an oven at 80 ° C for 24 hours to obtain a composite separator.
  • a gel polymer electrolyte membrane was prepared by the same method as in Example 4, and the thickness, the liquid absorption rate, and the ionic conductivity of the gel polymer electrolyte membrane were tested. The results are shown in Table 1.
  • PVDF-HFP was added to acetone, and stirred to dissolve to obtain a PVDF-HFP gel solution.
  • the content of PVDF-HFP in the gel solution was 10% by weight.
  • the polypropylene separator was immersed in the PVDF-HFP gel solution, taken out after 5 minutes, then immersed in water, taken out after 30 minutes, and finally vacuum dried in an oven at 80 ° C for 24 hours to obtain a composite separator.
  • a gel polymer electrolyte membrane was prepared by the same method as in Example 4, and the thickness, the liquid absorption rate, and the ionic conductivity of the gel polymer electrolyte membrane were tested. The results are shown in Table 1.
  • the commercial nano barium sulfate was dispersed in acetone to be dispersed, and PVDF-HFP was added thereto, and stirred and dissolved to prepare a composite gel liquid.
  • the mass ratio of nano-barium sulfate and PVDF-HFP having a surface modified with a lithium carboxylate group was 0.2:1.
  • the total content of PVDF-HFP and nano-barium sulfate having a surface modified with a lithium carboxylate group in the composite gel solution was 10% by weight.
  • the polypropylene separator was immersed in the composite gel solution, taken out after 5 minutes, then immersed in water, taken out after 30 minutes, and finally vacuum dried in an oven at 80 ° C for 24 hours to obtain a composite separator.
  • a gel polymer electrolyte membrane was prepared by the same method as in Example 4, and the thickness, the liquid absorption rate, and the ionic conductivity of the gel polymer electrolyte membrane were tested. The results are shown in Table 1.
  • Comparative example 1 Comparative example 2
  • Example 4 Example 5
  • Example 6 Diaphragm thickness ( ⁇ m) 30 31 31 33 36
  • Liquid absorption rate 180wt% 200wt% 250wt% 240wt% 250wt%
  • Ionic conductivity mS/cm 0.36 0.41 0.52 0.54 0.68
  • nanometer barium sulfate Adding nanometer barium sulfate to the gel polymer, because the nanometer barium sulfate has a large specific surface area, it is easy to adsorb liquid, and in addition, nano barium sulfate has a certain influence on the pore formation of the gel polymer, so that the void ratio of the formed pores is large. , can improve the liquid absorption rate of the composite diaphragm.
  • Comparative Example 2 commercial nano-barium sulfate was used, but the dispersion was uneven in the composite gel, and it was easy to agglomerate, and it was difficult to exhibit a large specific surface area. Therefore, the effect of improving the liquid absorption rate and the ionic conductivity of the composite separator was not remarkable. Further, the nano-barium sulfate used in Examples 4 to 6 has mesopores, and also promotes the improvement of the liquid absorption rate.
  • the composite separators of Example 4 and Comparative Example 2 were assembled into a lithium ion battery, and the other components of the lithium ion battery were the same, at 0.1 C, 0.5 C, 1 C, 2 C, 4 C, 8 C, and 0.2 C rates. Perform rate performance testing. Specifically, the lithium ion battery is firstly charged and discharged with a constant current of 5 C for 5 times, and all subsequent charging rates are 0.2 C, and the discharge rates are 0.5 C, 1 C, 2 C, 4 C, 8 C, and 0.2 C, respectively.
  • the charge and discharge cutoff voltage is 2.8 V ⁇ 4.3V. It can be seen from the cycle results that as the discharge rate increases, the discharge capacity of the lithium ion battery of Example 4 decreases less and has a better magnification.
  • the present invention prepares a highly dispersible nano-barium sulfate particle with a surface modified with a lithium carboxylate group.
  • the lithium carboxylate group makes the nano barium sulfate difficult to agglomerate and makes nano barium sulfate It can be uniformly dispersed after being mixed with the gel polymer; and the lithium carboxylate group changes the zeta potential of the nano barium sulfate, reduces the surface energy, and increases the concentration of the surface-loaded ions on the surface of the nano-barium sulfate particles.
  • the nano-barium sulfate particles are used as doping particles and uniformly mixed with the gel polymer matrix, the nano-barium sulfate can be uniformly dispersed in the gel polymer, and the lithium carboxylate group can promote the transport of lithium ions and increase the ions.

Abstract

本发明涉及一种复合隔膜，包括隔膜基材及与该隔膜基材复合的复合凝胶，该复合凝胶包括凝胶聚合物及分散于该凝胶聚合物中的表面修饰有羧酸锂基团的纳米硫酸钡。本发明还涉及一种复合隔膜的制备方法及一种锂离子电池。

Description

复合隔膜及其制备方法以及锂离子电池 技术领域
本发明涉及一种用于锂离子电池的复合隔膜及其制备方法以及应用该复合隔膜的锂离子电池。
背景技术
凝胶电解质，也称凝胶聚合物电解质，是聚合物与电解液的复合体，电解液被包裹在聚合物形成的网络中形成凝胶。采用凝胶聚合物电解质的锂离子电池俗称为凝胶聚合物电池。
与传统的液态电解质相比，凝胶聚合物电解质拥有不易漏液、高柔韧性、高物理化学稳定性等优点，但也存在一些缺点，如机械强度低，离子传导率低，电池的充放电倍率性能与液态电解液电池相比有一定差距，因而其应用大多限制在低倍率使用的数码电池领域。在动力电池领域，尚需提高凝胶聚合物电解质充放倍率电性能。为提高离子传导率，研究者在凝胶聚合物电解质中掺杂纳米陶瓷颗粒（如TiO2纳米颗粒、SiO2纳米颗粒、Al2O3纳米颗粒等），制备复合凝胶电解质，利用纳米粒子的络合效应及大比表面效应，在有机-无机界面形成快速离子传输通道，可提高凝胶电解质的离子传导性能，提高电池的倍率性能及循环稳定。但由于纳米陶瓷颗粒低Zeta电位以及高表面能，颗粒极易团聚，团聚的纳米颗粒几乎未发挥纳米材料本身所拥有的特性。实验表明，市售的大多数无机纳米颗粒均不易分散，即使在超声及随后的球磨处理后也达不到高分散的效果，不论聚合物的成分以及添加的纳米颗粒量多少，纳米颗粒都易于从基体中离析出来。
发明内容
有鉴于此，确有必要提供一种具有较高离子传导率复合隔膜及其制备方法，以及应用该复合隔膜的锂离子电池。
一种复合隔膜，包括隔膜基材及与该隔膜基材复合的复合凝胶，该复合凝胶包括凝胶聚合物及分散于该凝胶聚合物中的表面修饰有羧酸锂基团的纳米硫酸钡。
一种复合隔膜的制备方法，包括将羧酸锂溶解于有机溶剂形成的溶液加入到可溶性钡盐水溶液中，混合形成第一溶液；提供pH值为8~10的可溶性硫酸盐水溶液，将该可溶性硫酸盐水溶液加入到该第一溶液中，反应生成沉淀物；将该沉淀物分离、水洗并干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡；将该表面修饰有羧酸锂基团的纳米硫酸钡分散于有机溶剂，形成分散液；在该分散液中加入凝胶聚合物，均匀混合得到该复合凝胶；以及将该复合凝胶与隔膜基材复合，得到该复合隔膜。
一种锂离子电池，包括正极、负极以及设置在该正极与负极之间的凝胶聚合物电解质膜，该凝胶聚合物电解质膜包括所述复合隔膜，以及渗透于该复合隔膜中的非水电解液。
与现有技术比较，本发明制备了一种表面修饰有羧酸锂基团的高分散性纳米硫酸钡颗粒，该羧酸锂基团一方面使纳米硫酸钡易于均匀分散，另一方面改变了纳米硫酸钡的Zeta电位，降低表面能。将该纳米硫酸钡颗粒作为掺杂颗粒，与凝胶聚合物基体混合均匀，该纳米硫酸钡可以在该凝胶聚合物中均匀分散，并且羧酸锂基团能够促进锂离子的传输，提高离子电导率，从而使锂离子电池具有较高的倍率性能。
 附图说明
图1为本发明实施例1的纳米硫酸钡的扫描电镜照片。
图2为本发明实施例4的复合隔膜的扫描电镜照片。
图3为实施例4及对比例2的锂离子电池在不同电流倍率下的循环性能曲线。
具体实施方式
下面将结合附图及具体实施例对本发明提供的复合隔膜及其制备方法以及锂离子电池作进一步的详细说明。
本发明实施例提供一种复合隔膜的制备方法，其包括以下步骤：
S1，制备表面修饰有羧酸锂基团的纳米硫酸钡；
S2，制备复合凝胶；以及
S3，将该复合凝胶与隔膜基材复合，得到复合隔膜。
具体地，该步骤S1包括：
S11，将羧酸锂溶解于有机溶剂形成的溶液加入到可溶性钡盐水溶液中，混合形成第一溶液；
S12，提供一pH值为8~10的可溶性硫酸盐水溶液，将该可溶性硫酸盐水溶液加入到该第一溶液中，反应生成沉淀物；
S13，将该沉淀物分离、水洗并干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡；
在该步骤S11中，该羧酸锂与可溶性钡盐的Ba2+形成一种稳定的钡-羧酸锂络合物，该络合物在后续沉淀硫酸钡的过程中起到缓慢释放Ba2+的作用，使该硫酸钡颗粒不会生长过大，从而形成纳米硫酸钡。另外，在沉淀硫酸钡的过程中该纳米硫酸钡表面修饰有羧酸锂基团，从而使该纳米硫酸钡颗粒不易团聚，并有利于后续应用时的二次分散；在后续制备的硫酸钡复合隔膜中，该羧酸锂基团可以增加纳米硫酸钡颗粒表面载离子的浓度，促进锂离子在隔膜中传输。
该羧酸锂中含碳原子数至少为8个。该羧酸锂可以为油酸锂、硬脂酸锂、十二烷基苯甲酸锂、十六烷基苯甲酸锂或聚丙烯酸锂。该羧酸锂的质量优选为后续理论上形成的纳米硫酸钡质量的1%~5%。
该有机溶剂能够溶解羧酸锂，且在后续形成硫酸钡过程中使硫酸钡颗粒内部形成介孔。该有机溶剂为极性水溶性有机溶剂，可以为甲醇、乙醇、异丙醇、丙酮、N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)或N-甲基吡咯烷酮(NMP)等极性水溶性有机溶剂，优选为醇类有机溶剂，如乙醇、甲醇或异丙醇。该有机溶剂与可溶性钡盐水溶液体积比为1：1至2：1，优选为1：1。
该可溶性钡盐水溶液浓度范围为0.1mol/L~0.5mol/L，该可溶性钡盐为氯化钡、硝酸钡或硫化钡等常用可溶性钡盐。
在该步骤S12中，所述可溶性硫酸盐缓慢加入第一溶液，该可溶性硫酸盐的SO4 2-与第一溶液中缓慢释放的Ba2+形成纳米尺寸的硫酸钡，该纳米硫酸钡表面修饰有羧酸锂基团，内部含有介孔。所述可溶性硫酸盐可以为硫酸钠、硫酸钾、硫酸铵或硫酸铝等常用可溶性硫酸盐。所述可溶性硫酸盐水溶液浓度范围为0.1mol/L ~0.5mol/L。该可溶性硫酸盐与该可溶性钡盐的摩尔比为1:1。所述可溶性硫酸盐水溶液通过氨水、氢氧化钠或氢氧化钾等碱性溶液进行调节，使pH值优选为8~10。
在该S13步骤中，将沉淀物从溶液中离心分离，并经过水洗3~4次和真空干燥后，即得到表面修饰有羧酸锂基团的纳米硫酸钡，粒径范围为30nm~500nm，比表面积为5m2/g~20m2/g。每一纳米硫酸钡颗粒中均含有介孔，介孔的孔径范围为6nm~10nm。
在上述S11~S13步骤中，优选的，整个过程反应温度优选为15℃~45℃。
该步骤S2制备复合凝胶包括：
S21，将该表面修饰有羧酸锂基团的纳米硫酸钡分散于有机溶剂，形成分散液；以及
S22，在该分散液中加入凝胶聚合物，均匀混合得到该复合凝胶。
在该步骤S21中，该表面修饰有羧酸锂基团的纳米硫酸钡加入该有机溶剂后可通过机械搅拌或超声振荡等方式进行分散。搅拌及超声的时间视分散情况而定，优选为0.5~2小时。
在该步骤S22中，在搅拌该分散液的同时将该凝胶聚合物逐步加入该分散液中，继续搅拌，使分散液与凝胶聚合物均匀混合，从而使表面修饰有羧酸锂基团的纳米硫酸钡均匀分散在该凝胶聚合物基体中。
该表面修饰有羧酸锂基团的纳米硫酸钡与凝胶聚合物能够分散于该有机溶剂。该有机溶剂可以为极性溶剂，如NMP、DMF、 DMAc及丙酮中的一种或多种。该凝胶聚合物为凝胶电解质锂离子电池中常用的凝胶聚合物，如聚甲基丙烯酸甲酯（PMMA）、偏氟乙烯-六氟丙烯的共聚物(PVDF-HFP)，聚丙烯腈（PAN）及聚氧化乙烯（PEO）中的至少一种。
在该复合凝胶中，纳米硫酸钡:凝胶聚合物= 2 wt%~30wt%。该复合凝胶的固含量=(凝胶聚合物+纳米硫酸钡):溶剂= 2 wt%~15wt%。
该步骤S3将该复合凝胶与隔膜基材复合的步骤具体可以包括：
S31，将步骤S2的复合凝胶附着于隔膜基材上，形成复合凝胶层；
S32，将附着有该复合凝胶层的该隔膜基材浸于造孔剂中，从而在凝胶聚合物中造孔；以及
S33，烘干得到所述复合隔膜。
在步骤S31中，可以采用刮涂、浸涂、挤出涂布等方法，将该复合凝胶涂覆于隔膜基材的两侧或单侧。例如可以是将该隔膜基材浸于该复合凝胶后取出，该复合凝胶可以渗透于该隔膜基材的孔隙中，并可以在该隔膜基材表面形成厚度为10微米以内的薄层。该隔膜基材可以为聚烯烃多孔膜，该聚烯烃多孔膜可以为聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯多孔膜或聚丙烯-聚乙烯-聚丙烯复合多孔膜。该基膜用于隔绝电子并使锂离子从多孔膜的微孔中通过。该基膜可以采用市售的锂离子电池隔膜，如日本旭化成Asahi、东燃化学Tonen、宇部Ube、美国Celgard等公司生产的隔膜产品。本实施例采用Celgard公司生产的Celgard-2325型隔膜。
在步骤S32中，该造孔剂为该凝胶聚合物的不良溶剂，如水、乙醇、甲醇、或其混合溶液，从而可以使该复合凝胶层中的溶剂从该凝胶聚合物中部分脱出，形成微孔。在一实施例中，该造孔剂为乙醇水溶液（乙醇含量2~20wt%）。该浸泡时间可以为0.5小时~5小时。从该造孔剂取出后该附着有复合凝胶层的隔膜基材可用去离子水浸泡。
在步骤S33中，优选在40°C~60°C干燥24小时~48小时，得到多孔的复合隔膜。
本发明实施例提供一种复合隔膜，其包括所述隔膜基材以及与该隔膜基材复合的复合凝胶。该复合凝胶可以为层状，附着在该隔膜基材表面。该隔膜基材具有孔隙，该复合凝胶可填充于该孔隙中。形成在该隔膜基材表面的该复合凝胶层厚度优选为2μm~10μm。
该复合凝胶包括凝胶聚合物及分散于该凝胶聚合物中的表面修饰有羧酸锂基团的纳米硫酸钡。该表面修饰有羧酸锂基团的纳米硫酸钡粒径约为30nm~500nm，优选为30 nm~120nm。该凝胶聚合物为凝胶电解质锂离子电池中常用的凝胶聚合物，如PMMA、PVDF-HFP， PAN及PEO中的至少一种。该表面修饰有羧酸锂基团的纳米硫酸钡在该凝胶聚合物中均匀分散。
另外，该复合凝胶还可包括一定量的有机溶剂，与该凝胶聚合物相溶。该有机溶剂可以为NMP、DMF、DMAc及丙酮中的一种或多种。
在该复合凝胶中的质量比为，纳米硫酸钡:凝胶聚合物= 2 wt%-30wt%。该复合凝胶的固含量=(凝胶聚合物+纳米硫酸钡):溶剂= 2 wt%-15wt%。
在使用时，可将该复合隔膜在非水电解液中浸泡，形成凝胶聚合物电解质膜。
所述纳米硫酸钡表面修饰有羧酸锂基团，该纳米硫酸钡不易团聚，易于均匀分散，在制备复合凝胶的过程中能够均匀地分散在凝胶聚合物中，不会产生偏析。所述纳米硫酸钡表面基团含有锂离子，进一步有利于锂离子在复合凝胶中传输。该纳米硫酸钡内部含有介孔，且该硫酸钡微粒与微粒之间形成一定的空隙，使该复合隔膜孔隙率增大，利于电解液的渗透，使隔膜的浸润性进一步得到改善。
本发明实施例提供一种锂离子电池，包括正极、负极以及设置在该正极与负极之间的凝胶聚合物电解质膜，该凝胶聚合物电解质膜包括该复合隔膜，以及渗透于该复合隔膜中的非水电解液。
该非水电解液包括溶剂及溶于溶剂的锂盐溶质，该溶剂可选自环状碳酸酯、链状碳酸酯、环状醚类、链状醚类、腈类及酰胺类中的一种或多种，如碳酸乙烯酯、碳酸丙烯酯、碳酸二乙酯、碳酸二甲酯、碳酸甲乙酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、二乙醚、乙腈、丙腈、苯甲醚、丁酸酯、戊二腈、已二腈、γ-丁内酯、γ-戊内酯、四氢呋喃、1,2-二甲氧基乙烷及乙腈及二甲基甲酰胺中的一种或多种。该锂盐溶质可选自氯化锂（LiCl）、六氟磷酸锂（LiPF6）、四氟硼酸锂（LiBF4）、甲磺酸锂（LiCH3SO3）、三氟甲磺酸锂（LiCF3SO3）、六氟砷酸锂（LiAsF6）、高氯酸锂（LiClO4）及双草酸硼酸锂（LiBOB）中的一种或多种。
该正极可包括正极集流体及正极材料层，该正极集流体用于担载该正极材料层并传导电流，形状可以为箔片或网状。该正极集流体的材料可以选自铝、钛或不锈钢。该正极材料层设置在该正极集流体至少一表面。该正极材料层包括正极活性材料，进一步可选择的包括导电剂以及粘结剂。导电剂以及粘结剂可以与所述正极活性材料均匀混合。该正极活性材料可以为如磷酸铁锂、尖晶石锰酸锂、钴酸锂或镍酸锂等。
该负极可包括负极集流体及负极材料层，该负极集流体用于担载该负极材料层并传导电流，形状可以为箔片或网状。该负极集流体的材料可以选自铜、镍或不锈钢。该负极材料层设置在该负极集流体至少一表面。该负极材料层包括负极活性材料，进一步可选择的包括导电剂以及粘结剂。导电剂以及粘结剂可以与所述负极活性材料均匀混合。该负极活性材料可以为石墨、乙炔黑、微珠碳、碳纤维、碳纳米管或裂解碳等。
实施例（一）纳米硫酸钡的制备
实施例1
将0.01g的油酸锂溶解于50ml的无水甲醇中形成的溶液加入到50ml，0.5mol/L的氯化钡溶液中，均匀混合20分钟~30分钟形成混合溶液；将50ml，0.5mol/L的硫酸钠溶液通过氨水调节至pH值为8~9，并缓慢加入到上述混合溶液中，经过离心处理分离得到沉淀物。将该沉淀物在去离子水中洗涤3次，最后在80°C干燥箱中真空干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡。请参阅图1，所述纳米硫酸钡颗粒的粒径较小，约为30nm~50nm，所述纳米硫酸钡颗粒与颗粒之间形成一定的空隙，并且每一纳米硫酸钡颗粒内部含有介孔，该介孔孔径为6nm-10nm。该纳米硫酸钡比表面积约为19.9m2/g。
实施例2
将0.02g的硬脂酸锂溶解于100ml的N,N-二甲基甲酰胺中形成的溶液加入到100ml，0.5mol/L的硝酸钡溶液中，均匀混合20分钟~30分钟形成混合溶液；将100ml，0.5mol/L的硫酸钾溶液用稀氢氧化钠溶液调节至pH值为8~9，并缓慢加入到上述混合溶液中，经过离心处理分离得到沉淀物。将该沉淀物在去离子水中洗涤3~4次，最后在80°C干燥箱中真空干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡。该纳米硫酸钡粒径为50nm~80nm。
实施例3
将0.03g的聚丙烯酸锂溶解于150ml的丙酮中形成的溶液加入到150ml，0.5mol/L的氯化钡溶液中，均匀混合20分钟-30分钟形成混合溶液；将150ml，0.5mol/L的硫酸铵溶液用稀氢氧化钾溶液调节至pH值为8~9，并缓慢加入到上述混合溶液中，经过离心处理分离得到沉淀物。将该沉淀物在去离子水中洗涤3次，最后在80°C干燥箱中真空干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡。该纳米硫酸钡粒径为80nm~120nm。
实施例（二）复合隔膜及凝胶聚合物电解质膜的制备
实施例4
将实施例1制备的表面修饰有羧酸锂基团的纳米硫酸钡分散于丙酮中形成分散液，加入PVDF-HFP，搅拌溶解，制得复合凝胶液。表面修饰有羧酸锂基团的纳米硫酸钡与PVDF-HFP的质量比为0.2:1。复合凝胶液中PVDF-HFP与表面修饰有羧酸锂基团的纳米硫酸钡的总含量为10wt%。将聚丙烯隔膜浸于该复合凝胶液，5分钟后取出，然后浸于水中，30分钟后取出，最后在烘箱中80°C真空干燥24小时，得到复合隔膜。请参阅图2，该复合隔膜表面存在大量微孔，复合凝胶在隔膜基材表面分布均匀，未看到纳米硫酸钡团聚颗粒。将该复合隔膜浸泡在电解液中，该电解液含有1.0M的LiPF6及EC与DEC按体积比1:1形成的混合溶剂。浸泡5分钟即可使该复合隔膜充分吸取电解液，形成凝胶聚合物电解质膜。对该复合隔膜的厚度、吸液率及凝胶聚合物电解质膜离子电导率进行测试，结果如表1所示。
实施例5
将实施例1制备的表面修饰有羧酸锂基团的纳米硫酸钡分散于N-甲基吡咯烷酮中形成分散液，加入PMMA，搅拌溶解，制得复合凝胶液。表面修饰有羧酸锂基团的纳米硫酸钡与PMMA的质量比为0.2:1。复合凝胶液中PMMA与表面修饰有羧酸锂基团的纳米硫酸钡的总含量为10wt%。将聚丙烯隔膜浸于该复合凝胶液，5分钟后取出，然后浸于水中，30分钟后取出，最后在烘箱中80°C真空干燥24小时，得到复合隔膜。通过与实施例4相同的方法制备凝胶聚合物电解质膜，对该复合隔膜的厚度、吸液率及凝胶聚合物电解质膜离子电导率进行测试，结果如表1所示。
实施例6
将实施例1制备的表面修饰有羧酸锂基团的纳米硫酸钡分散于N,N-二甲基甲酰胺中形成分散液，加入PAN，搅拌溶解，制得复合凝胶液。表面修饰有羧酸锂基团的纳米硫酸钡与PAN的质量比为0.2:1。复合凝胶液中PAN与表面修饰有羧酸锂基团的纳米硫酸钡的总含量为10wt%。将聚丙烯隔膜浸于该复合凝胶液，5分钟后取出，然后浸于水中，30分钟后取出，最后在烘箱中80°C真空干燥24小时，得到复合隔膜。通过与实施例4相同的方法制备凝胶聚合物电解质膜，对该复合隔膜的厚度、吸液率及凝胶聚合物电解质膜离子电导率进行测试，结果如表1所示。
对比例1
在丙酮中加入PVDF-HFP，搅拌溶解，制得PVDF-HFP凝胶液。凝胶液中PVDF-HFP的含量为10wt%。将聚丙烯隔膜浸于该PVDF-HFP凝胶液中，5分钟后取出，然后浸于水中，30分钟后取出，最后在烘箱中80°C真空干燥24小时，得到复合隔膜。通过与实施例4相同的方法制备凝胶聚合物电解质膜，对该复合隔膜的厚度、吸液率及凝胶聚合物电解质膜离子电导率进行测试，结果如表1所示。
对比例2
将商品化的纳米硫酸钡分散于丙酮中进行分散，加入PVDF-HFP，搅拌溶解，制得复合凝胶液。表面修饰有羧酸锂基团的纳米硫酸钡与PVDF-HFP的质量比为0.2:1。复合凝胶液中PVDF-HFP与表面修饰有羧酸锂基团的纳米硫酸钡的总含量为10wt%。将聚丙烯隔膜浸于该复合凝胶液，5分钟后取出，然后浸于水中，30分钟后取出，最后在烘箱中80°C真空干燥24小时，得到复合隔膜。通过与实施例4相同的方法制备凝胶聚合物电解质膜，对该复合隔膜的厚度、吸液率及凝胶聚合物电解质膜离子电导率进行测试，结果如表1所示。
表1
对比例1 对比例2 实施例4 实施例5 实施例6
隔膜厚度 (μm) 30 31 31 33 36
吸液率 180wt% 200wt% 250wt% 240wt% 250wt%
离子电导率 (mS/cm) 0.36 0.41 0.52 0.54 0.68
在测量吸液率时，将复合隔膜浸渍于电解液中12小时，用吸水纸吸净表面液体，测量浸渍前质量W0及浸渍后质量W1，吸液率=（W1-W0）/W0。通过上述实验数据可以看到，实施例4~6的复合隔膜对电解液的吸液率及离子电导率相对与对比例1及2均有显著提高。在凝胶聚合物中加入纳米硫酸钡，由于该纳米硫酸钡比表面积大，易于吸附液体，另外，纳米硫酸钡对凝胶聚合物的成孔有一定影响，使所成孔的空隙率较大，可以提高复合隔膜的吸液率。而对比例2虽然使用商品化纳米硫酸钡，但在复合凝胶中分散不均匀，易于团聚，难以发挥比表面积大的性质，因此对复合隔膜的吸液率及离子电导率提高效果不明显。另外实施例4~6所用的纳米硫酸钡具有介孔，对吸液率的提高也有促进作用。
请参阅图3，分别将实施例4及对比例2的复合隔膜组装锂离子电池，锂离子电池的其他组件均相同，在0.1C、0.5C、1C、2C、4C、8C、0.2C倍率下进行倍率性能测试。具体地，锂离子电池先用0.1C电流进行恒流充放电5次，后续的所有充电倍率均为0.2C，放电倍率依次为0.5C、1C、2C、4C、8C及0.2C，各循环5次，充放电截止电压为2.8 V ~4.3V。从循环结果可以看到，随着放电倍率的增加，实施例4的锂离子电池放电容量下降较小，具有较好的倍率。
本发明实施例制备了一种表面修饰有羧酸锂基团的高分散性纳米硫酸钡颗粒，在沉淀硫酸钡的过程中该羧酸锂基团使纳米硫酸钡不易团聚，并且使纳米硫酸钡在后续与凝胶聚合物混合时能够分散均匀；并且该羧酸锂基团改变了纳米硫酸钡的Zeta电位，降低表面能，且增加了纳米硫酸钡颗粒表面载离子的浓度。将该纳米硫酸钡颗粒作为掺杂颗粒，与凝胶聚合物基体混合均匀，该纳米硫酸钡可以在该凝胶聚合物中均匀分散，且羧酸锂基团能够促进锂离子的传输，提高离子电导率，从而使锂离子电池具有较高的倍率性能。
另外，本领域技术人员还可在本发明精神内做其他变化，当然，这些依据本发明精神所做的变化，都应包含在本发明所要求保护的范围之内。

Claims (13)

  1. 一种复合隔膜，包括隔膜基材及与该隔膜基材复合的复合凝胶，其特征在于，该复合凝胶包括凝胶聚合物及分散于该凝胶聚合物中的表面修饰有羧酸锂基团的纳米硫酸钡。
  2. 如权利要求1所述的复合隔膜，其特征在于，所述羧酸锂基团中碳原子数至少为8个。
  3. 如权利要求1所述的复合隔膜，其特征在于，所述纳米硫酸钡内部含有介孔。
  4. 如权利要求1所述的复合隔膜，其特征在于，该复合凝胶为层状，附着在该隔膜基材表面。
  5. 如权利要求4所述的复合隔膜，其特征在于，所述层状的复合凝胶的厚度为2μm~10μm。
  6. 如权利要求1所述的复合隔膜，其特征在于，该表面修饰有羧酸锂基团的纳米硫酸钡粒径约为30nm~500nm。
  7. 如权利要求1所述的复合隔膜，其特征在于，该凝胶聚合物为聚甲基丙烯酸甲酯、偏氟乙烯-六氟丙烯的共聚物，聚丙烯腈及聚氧化乙烯中的至少一种。
  8. 如权利要求1所述的复合隔膜，其特征在于，该纳米硫酸钡与凝胶聚合物的质量比为2 wt%~30wt%。
  9. 一种复合隔膜的制备方法，包括：
    将羧酸锂溶解于有机溶剂形成的溶液加入到可溶性钡盐水溶液中，混合形成第一溶液；
    提供一pH值为8~10的可溶性硫酸盐水溶液，将该可溶性硫酸盐水溶液加入到该第一溶液中，反应生成沉淀物；
    将该沉淀物分离、水洗并干燥，得到表面修饰有羧酸锂基团的纳米硫酸钡；
    将该表面修饰有羧酸锂基团的纳米硫酸钡分散于有机溶剂，形成分散液；
    在该分散液中加入凝胶聚合物，均匀混合得到该复合凝胶；以及
    将该复合凝胶与隔膜基材复合，得到该复合隔膜。
  10. 如权利要求9所述的复合隔膜的制备方法，其特征在于，所述第一溶液中有机溶剂与可溶性钡盐水溶液体积比为1:1至2:1，所述有机溶剂为极性水溶性有机溶剂。
  11. 如权利要求9所述的复合隔膜的制备方法，其特征在于，所述羧酸锂为油酸锂、硬脂酸锂、聚丙烯酸锂、十二烷基苯甲酸锂及十六烷基苯甲酸锂中的一种或多种的混合物，所述羧酸锂质量为纳米硫酸钡质量的1%~5%。
  12. 如权利要求9所述的复合隔膜的制备方法，其特征在于，该复合凝胶与隔膜基材复合的步骤具体包括：
    将该复合凝胶附着于隔膜基材上，形成复合凝胶层；
    将附着有该复合凝胶层的该隔膜基材浸于造孔剂中，从而在凝胶聚合物中造孔；以及
    烘干得到所述复合隔膜。
  13. 一种锂离子电池，包括正极、负极以及设置在该正极与负极之间的凝胶聚合物电解质膜，其特征在于，该凝胶聚合物电解质膜包括如权利要求1~8中任意一项所述的复合隔膜，以及渗透于该复合隔膜中的非水电解液。
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CN109004160B (zh) * 2018-06-20 2019-11-29 上海恩捷新材料科技股份有限公司 一种锂电池固态电解质用隔膜及其制作方法
CN110048057B (zh) * 2019-03-25 2021-11-19 重庆恩捷纽米科技股份有限公司 表面改性pmma/pvdf混合涂覆的锂电池复合隔膜及其制备方法
CN112909430A (zh) * 2019-12-03 2021-06-04 恒大新能源技术(深圳)有限公司 锂离子电池隔膜及其制备方法和锂离子电池

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002025527A (ja) * 2000-07-03 2002-01-25 Japan Storage Battery Co Ltd 非水電解液二次電池
CN103579560A (zh) * 2012-08-01 2014-02-12 华为技术有限公司 电池隔膜及其制备方法和锂离子电池、通信设备
CN104088155A (zh) * 2014-06-25 2014-10-08 江苏华东锂电技术研究院有限公司 复合隔膜及其制备方法，以及锂离子电池
CN104882580A (zh) * 2015-04-09 2015-09-02 江苏华东锂电技术研究院有限公司 复合隔膜及其制备方法以及锂离子电池

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101792167A (zh) * 2010-01-29 2010-08-04 张颖 改性微化硫酸钡的制备方法
US20140255792A1 (en) * 2011-10-28 2014-09-11 Lubrizol Advanced Materials, Inc. Polyurethane Based Electrolyte Systems For Electrochemical Cells
JP6303412B2 (ja) * 2013-03-19 2018-04-04 株式会社村田製作所 電池、電解質層、電池パック、電子機器、電動車両、蓄電装置および電力システム
CN103840207B (zh) * 2014-03-12 2016-09-14 中国海诚工程科技股份有限公司 一种耐高温的锂离子电池凝胶聚合物电解质及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002025527A (ja) * 2000-07-03 2002-01-25 Japan Storage Battery Co Ltd 非水電解液二次電池
CN103579560A (zh) * 2012-08-01 2014-02-12 华为技术有限公司 电池隔膜及其制备方法和锂离子电池、通信设备
CN104088155A (zh) * 2014-06-25 2014-10-08 江苏华东锂电技术研究院有限公司 复合隔膜及其制备方法，以及锂离子电池
CN104882580A (zh) * 2015-04-09 2015-09-02 江苏华东锂电技术研究院有限公司 复合隔膜及其制备方法以及锂离子电池

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6526359B1 (ja) * 2018-01-24 2019-06-05 帝人株式会社 非水系二次電池用セパレータ及び非水系二次電池
WO2019146155A1 (ja) * 2018-01-24 2019-08-01 帝人株式会社 非水系二次電池用セパレータ及び非水系二次電池
CN111512471A (zh) * 2018-01-24 2020-08-07 帝人株式会社 非水系二次电池用隔膜及非水系二次电池
CN113039679A (zh) * 2018-10-03 2021-06-25 加利福尼亚大学董事会 用于储能装置的电阻性聚合物膜
CN113039679B (zh) * 2018-10-03 2023-08-04 加利福尼亚大学董事会 用于储能装置的电阻性聚合物膜

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