CN115000630A - Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof - Google Patents

Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof Download PDF

Info

Publication number
CN115000630A
CN115000630A CN202210706764.7A CN202210706764A CN115000630A CN 115000630 A CN115000630 A CN 115000630A CN 202210706764 A CN202210706764 A CN 202210706764A CN 115000630 A CN115000630 A CN 115000630A
Authority
CN
China
Prior art keywords
carbon fiber
khco
flame
lithium ion
ion battery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202210706764.7A
Other languages
Chinese (zh)
Other versions
CN115000630B (en
Inventor
李帆
张立斌
赵海玉
陈朝晖
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangsu Housheng New Energy Technology Co Ltd
Original Assignee
Jiangsu Housheng New Energy Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangsu Housheng New Energy Technology Co Ltd filed Critical Jiangsu Housheng New Energy Technology Co Ltd
Priority to CN202210706764.7A priority Critical patent/CN115000630B/en
Publication of CN115000630A publication Critical patent/CN115000630A/en
Application granted granted Critical
Publication of CN115000630B publication Critical patent/CN115000630B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M50/44—Fibrous material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—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
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Cell Separators (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention discloses a flame-retardant carbon fiber lithium ion battery diaphragm and a preparation method thereof; according to the invention, the hollow and porous hollow carbon fiber is prepared, the characteristic of high reactivity of isocyanate groups is utilized, the carbon fiber with loose pores is generated by the reaction with water, the surface area of the carbon fiber is increased, then the carbon fiber is treated by nitric acid, the surface area of the carbon fiber is increased, and simultaneously carboxyl groups are grafted on the surface of the carbon fiber to enhance the hydrophilicity of the carbon fiber, so that the KHCO-loaded carbon fiber is improved 3 Rate of reactionAnd (4) rate and capacity are improved. According to the invention, the carbon fiber and the PVDF powder are mixed to prepare the coating layer, the rough surface of the hollow carbon fiber is used for increasing the caking property and the electrolyte wettability, so that the problem of powder shedding of the PVDF coating in the processes of early coating and later cell manufacturing is greatly solved.

Description

Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a flame-retardant carbon fiber lithium ion battery diaphragm and a preparation method thereof.
Background
The polyolefin diaphragm is the most extensive lithium battery diaphragm at present, has extensive application market, but the polyolefin diaphragm has the shortcoming of low melting point, poor heat resistance, lower puncture-proof performance, and poor flame retardant property, especially in the electrolyte, because the polyolefin diaphragm is self-property reason, often with electrolyte wettability poor, cause its ion through rate low, seriously influenced the performance of battery, consequently, need develop a lithium ion battery diaphragm that has high wetting, high flame retardant and high mechanical properties at present urgently in order to satisfy the market and use.
Disclosure of Invention
The invention aims to provide a flame-retardant carbon fiber lithium ion battery diaphragm and a preparation method thereof, and aims to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: a flame-retardant carbon fiber lithium ion battery diaphragm has the following characteristics: the battery diaphragm comprises a base film and flame-retardant carbon fiber coating layers coated on two sides of the base film;
the flame-retardant carbon fiber coating layer comprises the following components in parts by weight: 5-10 parts of PVDF powder and 25-45 parts of KHCO 3 @ C fiber, 0.6-1.6 parts of dispersing agent, 7-10 parts of thickening agent, 2-4 parts of adhesive, 0.2-0.5 part of wetting agent and 0.05-0.2 part of defoaming agent.
Further, the dispersant is an aliphatic amide dispersant; the thickening agent is a carboxymethyl cellulose sodium thickening agent; the adhesive is a polyacrylic acid adhesive; the wetting agent is an alkyl sulfate wetting agent; the defoaming agent is polyether defoaming agent.
Further, said KHCO 3 @ C fiber is KHCO supported by hollow carbon fiber 3 And (4) preparing.
A preparation method of a flame-retardant carbon fiber lithium ion battery diaphragm comprises the following steps:
s1, preparing hydrophilic hollow carbon fibers;
s2, preparing KHCO3@ C fiber:
s21, mixing 3-5 parts of hydrophilic hollow carbon fiber with 100-plus-120 parts of ultrapure water, magnetically stirring for 1-1.5h, and then continuing to disperse for 1.5-3h by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, introducing carbon dioxide/nitrogen mixed gas, and continuously introducing gas for 2-4 hours;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting a suction filtration product, fully washing the suction filtration product by using deionized water, putting the suction filtration product in a vacuum drying oven for drying for 24 hours, and obtaining the KHCO3@ C fiber to be prepared after the vacuum drying is finished;
s3, mixing the dispersing agent, the PVDF powder and the KHCO 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 10-30min at the speed of 100-300rpm, adding the thickening agent, continuously stirring for 20-60min at the speed of 200-500 rpm, adding the binder, stirring for 30-50min at the speed of 350-500rpm, finally adding the wetting agent and the defoaming agent, continuously stirring for 20-40min at the speed of 400-600rpm, filtering to remove iron, and obtaining the KHCO coated by PVDF 3 @ C coating slurry;
s4, coating the PVDF with KHCO 3 And coating the @ C coating slurry on two sides of the polyolefin diaphragm, and baking and drying to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
Further, in step S1, the preparation method of the hydrophilic hollow carbon fiber specifically includes the following steps:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide to prepare a mixed solution, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning is finished to obtain a carbon fiber preform;
s13, heating the carbon fiber preform in air to 250-plus-300 ℃, preserving heat for 1-2h, then filling nitrogen, slowly heating to 950-plus-1050 ℃ under the protection of nitrogen, preserving heat for 1-2h for complete carbonization, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30-45min, performing vacuum load treatment for 1-1.5h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2-4 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1-2h, performing suction filtration and drying to obtain the hydrophilic hollow carbon fiber.
The application firstly utilizes the electrostatic spinning technology to prepare the hollow carbon fiber, diphenylmethane diisocyanate is added in external liquid of an electrostatic spinning machine as a foaming agent, the diphenylmethane diisocyanate contains-NCO groups which are unsaturated bonds and have higher reactivity, and because the atomic composition of the diphenylmethane diisocyanate contains N, O elements and has higher electronegativity, the diphenylmethane diisocyanate is easy to react with substances containing active hydrogen, after the diphenylmethane diisocyanate is mixed with water, the isocyanate groups can react with the water to cause the polymer solution to generate phase separation and cause pores inside the polymer, after the electrostatic spinning, N-dimethylformamide in the external liquid can be quickly volatilized under the action of high pressure to generate the hollow carbon fiber, and the hollow carbon fiber is reacted with the water in distilled water to generate the pores, and then the hollow carbon fiber is subjected to deoxidation and dehydrogenation reaction in a high-temperature environment, finally, the porous hollow carbon fiber is formed.
The introduction of the carbon fibers increases the mechanical property of the material on one hand, and enhances the conductivity of the material on the other hand, thereby being beneficial to enhancing the rapid transmission of lithium ions; in addition, the carbon fiber prepared by the method is of a hollow structure, so that the lithium ion conductivity is further improved, the specific surface area of the material is increased, and the liquid absorption and retention capacity of the diaphragm is enhanced.
Then, the invention uses concentrated nitric acid to graft the carbon fiber, and uses vacuum loading technology to ensure that the hollow pipe and the inner pore of the carbon fiber can still contact with sufficient concentrated nitric acid for modification, a rough surface with carboxyl is generated on the surface of the hollow pipe and the inner pore of the carbon fiber, and the hydrophilicity of the carbon fiber is enhanced and increasedThe surface area of the material is large, and more KHCO can be loaded 3 。
KHCO 3 The KHCO can be loaded on the surface of the carbon fiber to play a role of flame retardance, and when the temperature is raised to the decomposition temperature, the KHCO 3 Decompose to release water vapor and CO 2 Latent heat is absorbed, and the concentration of oxygen and combustible gas near the surface of a combustion object is diluted, so that surface combustion is difficult to carry out; the protective layer formed on the surface prevents oxygen and heat from entering, and the potassium carbonate generated by decomposition of the protective layer has good high-temperature resistance, so that the capability of resisting open fire of the material can be improved.
Meanwhile, in the preparation process, the invention also strictly limits the high-temperature heating and drying temperature, and the drying temperature is strictly limited below 80 ℃ so as to ensure KHCO in the preparation process 3 The product is degraded by heat.
Further, in step S11, the concentration of polymethyl methacrylate in the polymethyl methacrylate solution is 10 to 12 wt%, the concentration of diphenylmethane diisocyanate in the mixed solution is 16 to 27 wt%, and the concentration of polyacrylonitrile is 10 to 12 wt%.
Further, in step S12, the electrostatic spinning parameters are: the electrostatic spinning voltage is 12-15kv, the flow rate of the outer layer is 1.2-1.8mL/h, and the flow rate of the inner layer liquid is 1-1.5 mL/h.
Further, in step S22, the volume ratio of carbon dioxide to nitrogen in the carbon dioxide/nitrogen mixed gas is (65-75): (25-35).
Further, in step S23, the vacuum drying oven has working parameters of a drying temperature of 70 to 80 ℃ and a vacuum degree of 0.08 to 0.1 Mpa.
Further, in step S4, the temperature for baking and drying is 65-70 ℃.
Compared with the prior art, the invention has the following beneficial effects: the invention firstly prepares hollow and porous hollow carbon fiber, utilizes the characteristic of high reactivity of isocyanate group to react with water to generate carbon fiber with loose pores, increases the surface area of the carbon fiber, and then uses nitric acid to treat the carbon fiber, increases the surface area and grafts carboxyl on the surface of the carbon fiber, thereby enhancing the hydrophilicity of the carbon fiberThereby increasing the load KHCO 3 The reaction rate is increased, and the loading capacity is improved. According to the invention, the carbon fiber and the PVDF powder are mixed to prepare the coating layer, the rough surface of the hollow carbon fiber is used for increasing the caking property and the electrolyte wettability, so that the problem of powder shedding of the PVDF coating in the processes of early coating and later cell manufacturing is greatly solved.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1.
S1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 12 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring for 6 hours to prepare a mixed solution with the concentration of the diphenylmethane diisocyanate being 27 wt% and the concentration of the polyacrylonitrile being 12 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, setting electrostatic spinning voltage to be 15kv, outer layer flow velocity to be 1.8mL/h, inner layer liquid flow velocity to be 1.5mL/h, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1 hour, then filling nitrogen, slowly heating to 1050 ℃ under the protection of nitrogen, preserving heat for 1 hour for complete carbonization, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration, and drying to obtain the hydrophilic hollow carbon fiber.
S2, preparing KHCO 3 @ C fiber:
s21, mixing 5 parts of hydrophilic hollow carbon fiber with 120 parts of ultrapure water, magnetically stirring for 1 hour, and then continuously dispersing for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, and introducing carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting a filtration product, fully washing the filtration product by using deionized water, putting the filtration product into a vacuum drying oven, drying for 24 hours at the drying temperature of 80 ℃ and the vacuum degree of 0.08Mpa, and obtaining the KHCO to be prepared after the vacuum drying is finished 3 @ C fiber;
s3, according to the weight percentage, 1.2 percent of aliphatic amide dispersant, 7 percent of PVDF powder and 25 percent of KHCO are mixed 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 30min at the speed of 300pm, adding 9% of carboxymethyl cellulose sodium thickening agent, continuously stirring for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether type defoaming agent, continuously stirring for 30min at the speed of 550rpm, filtering and removing iron to obtain KHCO coated by PVDF 3 @ C coating slurry;
s4, coating the PVDF with KHCO 3 The @ C coating slurry is coated on two sides of a 9-micron-thick polyethylene diaphragm, the thickness of one-side coating is 3 microns, and the flame-retardant carbon fiber lithium ion battery diaphragm can be obtained by rolling after being baked in a 70-DEG C oven.
Example 2.
This example increased KHCO in step S3 compared to example 1 3 The amount of @ C fiber added;
s1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 12 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring for 6 hours to prepare a mixed solution with the diphenylmethane diisocyanate concentration of 27 wt% and the polyacrylonitrile content of 12 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, setting electrostatic spinning voltage to be 15kv, outer layer flow velocity to be 1.8mL/h, inner layer liquid flow velocity to be 1.5mL/h, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1h, filling nitrogen, slowly heating to 1050 ℃ under the protection of the nitrogen, preserving heat for 1h, completely carbonizing, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration, and drying to obtain the hydrophilic hollow carbon fiber.
S2, preparing KHCO 3 @ C fiber:
s21, mixing 5 parts of hydrophilic hollow carbon fibers with 120 parts of ultrapure water, magnetically stirring for 1 hour, and then continuously dispersing for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, and introducing carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting a filtration product, fully washing with deionized water, and carrying out suction filtrationPlacing the product in a vacuum drying oven at 80 deg.C and vacuum degree of 0.08Mpa, drying for 24 hr, and vacuum drying to obtain KHCO 3 @ C fibers;
s3, according to the weight percentage, 1.2 percent of aliphatic amide dispersant, 7 percent of PVDF powder and 35 percent of KHCO are mixed 3 Mixing the @ C fibers, adding into ultrapure water, premixing for 30min at the speed of 300pm, adding 9% of carboxymethylcellulose sodium thickening agent, continuously stirring for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether type defoaming agent, continuously stirring for 30min at the speed of 550rpm, filtering and deironing to obtain the KHCO coated with PVDF 3 @ C coating slurry;
s4, coating the PVDF on the KHCO 3 And coating the @ C coating slurry on two sides of a 9-micron-thick polyethylene diaphragm, wherein the thickness of one side of the diaphragm is 3 microns, and baking the diaphragm in a 70-DEG C oven and then rolling the diaphragm to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
Example 3.
This example increased KHCO in step S3 compared to example 1 3 The amount of @ C fiber added;
s1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 12 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring for 6 hours to prepare a mixed solution with the diphenylmethane diisocyanate concentration of 27 wt% and the polyacrylonitrile content of 12 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, wherein electrostatic spinning voltage is 15kv, the flow rate of an outer layer is 1.8mL/h, the flow rate of an inner layer liquid is 1.5mL/h, distilled water is used as a coagulating bath, fibers obtained by spinning are settled in the distilled water, and after spinning is finished, suction filtration is carried out to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1h, filling nitrogen, slowly heating to 1050 ℃ under the protection of the nitrogen, preserving heat for 1h, completely carbonizing, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration, and drying to obtain the hydrophilic hollow carbon fiber.
S2, preparing KHCO 3 @ C fiber:
s21, mixing 5 parts of hydrophilic hollow carbon fibers with 120 parts of ultrapure water, magnetically stirring for 1 hour, and then continuously dispersing for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, and introducing carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting a filtration product, fully washing the filtration product by using deionized water, putting the filtration product into a vacuum drying oven, drying for 24 hours at the drying temperature of 80 ℃ and the vacuum degree of 0.08Mpa, and obtaining the KHCO to be prepared after the vacuum drying is finished 3 @ C fiber;
s3, according to the weight percentage, 1.2 percent of aliphatic amide dispersant, 7 percent of PVDF powder and 45 percent of KHCO 3 Mixing the @ C fibers, adding into ultrapure water, premixing for 30min at the speed of 300pm, adding 9% of carboxymethylcellulose sodium thickening agent, continuously stirring for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether type defoaming agent, continuously stirring for 30min at the speed of 550rpm, filtering and deironing to obtain the KHCO coated with PVDF 3 @ C coating slurry;
s4, coating the PVDF with KHCO 3 Coating the @ C coating slurry on two sides of a 9-micron-thick polyethylene diaphragm, wherein the thickness of one side of the diaphragm is 3 microns, baking the diaphragm in a 70-DEG C oven, and rolling the diaphragm to obtain the flame-retardant carbon fiber lithiumAn ion battery separator.
Example 4.
S1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 10 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring for 6 hours to prepare a mixed solution with the diphenylmethane diisocyanate concentration of 16 wt% and the polyacrylonitrile content of 10 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, setting electrostatic spinning voltage to be 12kv, outer layer flow velocity to be 1.2mL/h, inner layer liquid flow velocity to be 1mL/h, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1h, filling nitrogen, slowly heating to 950 ℃ under the protection of the nitrogen, preserving heat for 1h, completely carbonizing, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration, and drying to obtain the hydrophilic hollow carbon fiber.
S2, preparing KHCO 3 @ C fiber:
s21, mixing 3 parts of hydrophilic hollow carbon fiber with 100 parts of ultrapure water, magnetically stirring for 1 hour, and then continuously dispersing for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, and introducing carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s23, after the ventilation treatment is finished, carrying out suction filtration and collecting a filtration product to ensure thatWashing with deionized water, vacuum drying at 80 deg.C under 0.08Mpa for 24 hr in a vacuum drying oven, and vacuum drying to obtain KHCO 3 @ C fibers;
s3, according to the weight percentage, 0.6 percent of aliphatic amide dispersant, 5 percent of PVDF powder and 25 percent of KHCO are mixed 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 10min at the speed of 100pm, adding 7% of carboxymethyl cellulose sodium thickening agent, continuously stirring for 20min at the speed of 200rpm, adding 2% of polyacrylic acid binder, continuously stirring for 30min at the speed of 350rpm, finally adding 0.2% of alkyl sulfate wetting agent and 0.05% of polyether type defoaming agent, continuously stirring for 20min at the speed of 400rpm, filtering and removing iron to obtain KHCO coated by PVDF 3 @ C coating slurry;
s4, coating the PVDF with KHCO 3 And coating the @ C coating slurry on two sides of a 9-micron-thick polyethylene diaphragm, wherein the thickness of one side of the diaphragm is 3 microns, and baking the diaphragm in a 70-DEG C oven and then rolling the diaphragm to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
Example 5.
S1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 10 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an inner solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring the mixture for 6 hours to prepare a mixed solution of the diphenylmethane diisocyanate with the concentration of 16 wt% and the polyacrylonitrile with the concentration of 10 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, setting electrostatic spinning voltage to be 12kv, outer layer flow velocity to be 1.2mL/h, inner layer liquid flow velocity to be 1mL/h, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1h, filling nitrogen, slowly heating to 950 ℃ under the protection of the nitrogen, preserving heat for 1h, completely carbonizing, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration and drying to obtain the hydrophilic hollow carbon fiber.
S2, preparing KHCO 3 @ C fiber:
s21, mixing 3 parts of hydrophilic hollow carbon fiber with 100 parts of ultrapure water, magnetically stirring for 1 hour, and then continuously dispersing for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, and introducing carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting a filtration product, fully washing the filtration product by using deionized water, putting the filtration product into a vacuum drying oven, drying for 24 hours at the drying temperature of 80 ℃ and the vacuum degree of 0.08Mpa, and obtaining the KHCO to be prepared after the vacuum drying is finished 3 @ C fibers;
s3, according to the weight percentage, 1.6 percent of aliphatic amide dispersant, 10 percent of PVDF powder and 45 percent of KHCO are mixed 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 10min at the speed of 100pm, adding 10% of carboxymethyl cellulose sodium thickening agent, continuously stirring for 20min at the speed of 200rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 350rpm, finally adding 0.5% of alkyl sulfate wetting agent and 0.2% of polyether type defoaming agent, continuously stirring for 20min at the speed of 400rpm, filtering and removing iron to obtain KHCO coated by PVDF 3 @ C coating slurry;
s4, coating the PVDF on the KHCO 3 And coating the @ C coating slurry on two sides of a 9-micron-thick polyethylene diaphragm, wherein the thickness of one side of the diaphragm is 3 microns, and baking the diaphragm in a 70-DEG C oven and then rolling the diaphragm to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
Comparative example 1.
Comparative example 1 no KHCO was prepared 3 @ C fibers;
s1, according to weight percentage, 1.2 percent of aliphatic amide dispersant, 7 percent of PVDF powder and 45 percent of KHCO 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 30min at the speed of 300pm, adding 9% of carboxymethyl cellulose sodium thickening agent, continuously stirring for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether type defoaming agent, continuously stirring for 30min at the speed of 550rpm, filtering and removing iron to obtain KHCO coated by PVDF 3 @ C coating slurry;
s2, coating KHCO on PVDF 3 The @ C coating slurry is coated on two sides of a 9-micron-thick polyethylene diaphragm, the thickness of one-side coating is 3 microns, and the flame-retardant carbon fiber lithium ion battery diaphragm can be obtained by rolling after being baked in a 70-DEG C oven.
Comparative example 2.
In contrast to example 1, no coating was prepared for this comparative example;
comparative example 3.
Comparative example no KHCO was prepared, compared to example 1 3 @ C fiber;
s1, preparing hydrophilic hollow carbon fibers:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a 12 wt% polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an inner solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide, continuously stirring for 3-6h to prepare a mixed solution with the diphenylmethane diisocyanate concentration of 27 wt% and the polyacrylonitrile content of 12 wt%, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, setting electrostatic spinning voltage to be 15kv, outer layer flow velocity to be 1.8mL/h, inner layer liquid flow velocity to be 1.5mL/h, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning to obtain a carbon fiber preform;
s13, heating the carbon fiber preform to 250 ℃ in air, preserving heat for 1h, filling nitrogen, slowly heating to 1050 ℃ under the protection of the nitrogen, preserving heat for 1h, completely carbonizing, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30min, performing vacuum load treatment for 1h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1h, performing suction filtration, and drying to obtain the hydrophilic hollow carbon fiber.
S2, mixing 1.2% of aliphatic amide dispersant, 7% of PVDF powder and 25% of hydrophilic hollow carbon fiber according to weight percentage, adding the mixture into ultrapure water, premixing the mixture for 30min at the speed of 300pm, adding 9% of carboxymethyl cellulose sodium thickener, continuing to stir the mixture for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuing to stir the mixture for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether defoamer, continuing to stir the mixture for 30min at the speed of 550rpm, and filtering the mixture to remove iron to obtain coating slurry;
s3, coating the coating slurry on two sides of a polyethylene diaphragm with the thickness of 9 microns, wherein the thickness of a single-side coating is 3 microns, and baking the polyethylene diaphragm in an oven at 70 ℃ and then rolling the polyethylene diaphragm to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
Comparative example 4.
In the comparative example, hydrophilic hollow carbon fibers are not prepared, and AM-C-F-1 nano carbon fibers sold by Yam scientific and technology Limited, Zhejiang are only used for equivalent substitution;
s1, preparing KHCO 3 @ C fiber:
s11, mixing 5 parts of carbon nanofibers with 120 parts of ultrapure water, magnetically stirring for 1 hour, and then continuing to disperse for 1.5 hours by ultrasonic to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s12, adding potassium carbonate, preparing the carbon nanofiber dispersion liquid into a saturated potassium carbonate solution, and introducing a carbon dioxide/nitrogen mixed gas, wherein the volume ratio of carbon dioxide to nitrogen in the mixed gas is 67.5: 32.5, continuously ventilating for 2.5 h;
s13, after the ventilation treatment is finished, carrying out suction filtration and collectingFiltering the product, washing with deionized water, drying in a vacuum drying oven at 80 deg.C and 0.08Mpa for 24 hr, and vacuum drying to obtain KHCO 3 @ C fiber;
s2, according to the weight percentage, 1.2 percent of aliphatic amide dispersant, 7 percent of PVDF powder and 25 percent of KHCO are mixed 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 30min at the speed of 300pm, adding 9% of carboxymethyl cellulose sodium thickening agent, continuously stirring for 20min at the speed of 450rpm, adding 4% of polyacrylic acid binder, continuously stirring for 30min at the speed of 500rpm, finally adding 0.35% of alkyl sulfate wetting agent and 0.15% of polyether type defoaming agent, continuously stirring for 30min at the speed of 550rpm, filtering and removing iron to obtain KHCO coated by PVDF 3 @ C coating slurry;
s3, coating the PVDF with KHCO 3 And coating the @ C coating slurry on two sides of a 9-micron-thick polyethylene diaphragm, wherein the thickness of one side of the diaphragm is 3 microns, and baking the diaphragm in a 70-DEG C oven and then rolling the diaphragm to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
In the above embodiment, the polyacrylonitrile is a polyacrylonitrile product with a molecular weight of 15 ten thousand produced by the Hubei Energer Hua Engineers technology Limited company;
the polymethylmethacrylate is a polymethylmethacrylate product sold by sigma aldrich (shanghai) trade ltd under the designation NIST 1488;
the diphenylmethane diisocyanate is a diphenylmethane diisocyanate product sold by Wuhan Dynasty chemical industry Co., Ltd;
the dispersant is a vinyl bis stearamide product sold by Pan (Shanghai) International trade company, Inc.;
the thickening agent is sodium carboxymethyl cellulose;
the adhesive is polyacrylic acid sold by sigma aldrich (Shanghai) trade company Limited and having a molecular weight of 45 ten thousand;
the wetting agent is sodium dodecyl sulfate;
the defoaming agent is a PT-5021 type polyether defoaming agent sold by field chemical;
the polyethylene diaphragm is prepared by rolling and forming a film by using low-density polyethylene, wherein the low-density polyethylene is low-density polyethylene sold by Dow company in America and the model number of the polyethylene is 320E.
And (3) detection, namely performing performance detection on the products of the examples 1-5 and the comparative examples 1-4, wherein the detection results are shown in the following table:
as can be seen from the table:
Figure BDA0003705695470000121
as can be seen by comparing examples 1-5 with comparative examples 1-4, KHCO is present 3 The modification of the @ C fiber greatly improves the mechanical strength (needling strength) of the diaphragm;
comparing examples 1-3 with comparative examples 1-2, it can be seen that KHCO is contained in the slurry 3 When the mass ratio of the @ C fiber is gradually increased from 25% to 45%, the anode-hot-pressing stripping performance of the corresponding composite diaphragm is better and better, namely the adhesion to the anode piece is better and better, and the adhesion is higher than that of the anode piece without KHCO 3 The composite diaphragm corresponding to the size of the @ C fiber is far higher than a pure polyolefin diaphragm without a coating;
comparing examples 1-3 with comparative examples 1-2, it can be seen that KHCO is contained in the slurry 3 When the mass ratio of the @ C fiber is gradually increased from 25% to 45%, the ionic conductivity of the corresponding composite diaphragm is higher and higher than that of the composite diaphragm without KHCO 3 The composite diaphragm corresponding to the sizing agent of the @ C fiber is simultaneously far higher than a pure polyolefin diaphragm without a coating, and the KHCO is proved 3 Modification of the @ C fiber can effectively improve the ionic conductivity of the diaphragm;
when examples 1 to 3 and comparative example 1 are compared, KHCO is contained in the slurry 3 When the mass ratio of the @ C fiber is gradually increased to 45% from 25%, the peeling strength of the coating corresponding to the composite diaphragm is higher and higher, namely, the powder falling prevention capacity is stronger and stronger, and the peeling strength is far higher than that of the coating without KHCO 3 The composite diaphragm corresponding to the pulp of the @ C fiber proves KHCO 3 The effectiveness of the @ C fiber on shedding prevention;
the examples 1 to 3,Comparison of comparative examples 1-2 shows that KHCO is present in the slurry 3 When the mass ratio of the @ C fiber is gradually increased from 25% to 45%, the thermal shrinkage performance of the corresponding composite diaphragm is better and better, and the thermal shrinkage performance is better than that of the composite diaphragm without KHCO 3 The composite diaphragm corresponding to the pulp of the @ C fiber is far superior to a pure polyolefin diaphragm without a coating layer, and the KHCO is proved 3 The effectiveness of the @ C fiber in improving the heat resistance and the KHCO of the C fiber, PVDF and possessing the flame retardant property 3 The three components can act synergistically to further improve the heat shrinkage performance of the diaphragm.
Comparing examples 1-3 with comparative examples 1-2, it can be seen that KHCO is contained in the slurry 3 When the mass ratio of the @ C fiber is gradually increased from 25% to 35%, the air permeability of the corresponding composite diaphragm is deteriorated, and when KHCO is adopted 3 When the mass ratio of the @ C fiber is further increased to 45%, the air permeability of the corresponding composite diaphragm is seriously deteriorated, and the @ C fiber and the composite diaphragm are all compared without KHCO 3 The composite membrane corresponding to the size of the @ C fiber is inferior to the pure polyolefin membrane without coating, so in order to balance the various properties of the composite membrane, KHCO 3 The amount of @ C fiber added is moderate, not as high as is preferred.
When examples 1 to 3 and comparative examples 1 to 2 are compared, as for the oxygen index: PVDF-coated KHCO 3 Composite diaphragm modified by @ C fiber and without addition of KHCO 3 Composite membranes corresponding to a slurry of @ C fibers > uncoated pure polyolefin membranes, confirming KHCO 3 The @ C fiber can effectively improve the flame retardant property of the diaphragm.
When examples 1 to 3 are compared with comparative examples 3 to 4, KHCO prepared in the present invention can be seen 3 In the @ C fiber, the hollow carbon fiber is porous and hollow, has larger specific surface area and can load more KHCO 3 And because the structure is porous, the surface of the composite material is rougher compared with the surface of common carbon fiber, and the composite material can be better crosslinked and fixed with PVDF.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The flame-retardant carbon fiber lithium ion battery diaphragm is characterized in that: the battery diaphragm comprises a base film and flame-retardant carbon fiber coating layers coated on two sides of the base film;
wherein the flame-retardant carbon fiber coating layer is KHCO coated by PVDF 3 Coating the @ C fiber coating slurry on two sides of the base film and then drying to obtain the @ C fiber coating slurry;
the PVDF-coated KHCO is calculated by weight percentage 3 The @ C fiber coating slurry comprises the following components: 5-10% of PVDF powder and 25-45% of KHCO 3 @ C fiber, 0.6-1.6% of dispersing agent, 7-10% of thickening agent, 2-4% of adhesive, 0.2-0.5% of wetting agent, 0.05-0.2% of defoaming agent and the balance of ultrapure water.
2. The flame-retardant carbon fiber lithium ion battery separator according to claim 1, characterized in that: the dispersant is aliphatic amide dispersant; the thickening agent is a carboxymethyl cellulose sodium thickening agent; the adhesive is a polyacrylic acid adhesive; the wetting agent is an alkyl sulfate wetting agent; the defoaming agent is a polyether defoaming agent.
3. The flame-retardant carbon fiber lithium ion battery separator according to claim 1, characterized in that: said KHCO 3 @ C fiber is KHCO supported by hollow carbon fiber 3 And (4) preparing.
4. The preparation method of the flame-retardant carbon fiber lithium ion battery diaphragm is characterized by comprising the following steps of:
s1, preparing hydrophilic hollow carbon fibers;
s2, preparing KHCO 3 @ C fiber:
s21, mixing 3-5 parts of hydrophilic hollow carbon fiber with 100-120 parts of ultrapure water in parts by weight, magnetically stirring for 1-1.5h, and then continuing to disperse for 1.5-3h by ultrasound to obtain uniformly dispersed hydrophilic hollow carbon fiber dispersion liquid;
s22, adding potassium carbonate, preparing the hydrophilic hollow carbon fiber dispersion liquid into a saturated potassium carbonate solution, introducing carbon dioxide/nitrogen mixed gas, and continuously introducing gas for 2-4 hours;
s23, after the ventilation treatment is finished, carrying out suction filtration, collecting suction filtration products, fully washing with deionized water, placing the suction filtration products in a vacuum drying oven for drying for 24 hours, and obtaining KHCO to be prepared after the vacuum drying is finished 3 @ C fiber;
s3, mixing the dispersing agent, the PVDF powder and the KHCO 3 Mixing the @ C fiber, adding the ultra-pure water, premixing for 10-30min at the speed of 100-300rpm, adding the thickening agent, continuously stirring for 20-60min at the speed of 200-500 rpm, adding the binder, stirring for 30-50min at the speed of 350-500rpm, finally adding the wetting agent and the defoaming agent, continuously stirring for 20-40min at the speed of 400-600rpm, filtering to remove iron, and obtaining the KHCO coated by PVDF 3 @ C coating slurry;
s4, coating the PVDF with KHCO 3 And coating the @ C coating slurry on two sides of the polyolefin diaphragm, and baking and drying to obtain the flame-retardant carbon fiber lithium ion battery diaphragm.
5. The preparation method of the flame-retardant carbon fiber lithium ion battery separator according to claim 4, characterized in that: in step S1, the method for preparing hydrophilic hollow carbon fibers specifically includes the following steps:
s11, dissolving polymethyl methacrylate in N, N-dimethylformamide, uniformly stirring to prepare a polymethyl methacrylate solution, and adding the solution into a coaxial electrostatic spinning machine to serve as an internal solution; mixing polyacrylonitrile and diphenylmethane diisocyanate, dissolving the mixture in N, N-dimethylformamide to prepare a mixed solution, and adding the mixed solution into a coaxial electrostatic spinning machine to serve as an external liquid;
s12, setting electrostatic spinning working parameters, taking distilled water as a coagulating bath, settling fibers obtained by spinning in the distilled water, and performing suction filtration after spinning is finished to obtain a carbon fiber preform;
s13, heating the carbon fiber preform in the air to 250-plus-300 ℃, preserving heat for 1-2h, then filling nitrogen, slowly heating to 950-plus-1050 ℃ under the protection of the nitrogen, preserving heat for 1-2h for complete carbonization, and cooling to room temperature to obtain hollow carbon fiber;
s14, immersing the hollow carbon fiber in concentrated nitric acid, performing ultrasonic dispersion for 30-45min, performing vacuum load treatment for 1-1.5h, performing suction filtration, alternately cleaning a suction filtration product with deionized water and ethanol for 2-4 times, immersing the suction filtration product in an absolute ethanol solution again, performing vacuum load for 1-2h, performing suction filtration and drying to obtain the hydrophilic hollow carbon fiber.
6. The preparation method of the flame-retardant carbon fiber lithium ion battery separator according to claim 5, characterized in that: in step S11, the polymethyl methacrylate solution has a polymethyl methacrylate concentration of 10 to 12 wt%, the mixed solution has a diphenylmethane diisocyanate concentration of 16 to 27 wt%, and the mixed solution has a polyacrylonitrile concentration of 10 to 12 wt%.
7. The preparation method of the flame-retardant carbon fiber lithium ion battery diaphragm according to claim 5, characterized by comprising the following steps: in step S12, the electrostatic spinning parameters are: the electrostatic spinning voltage is 12-15kv, the flow rate of the outer layer is 1.2-1.8mL/h, and the flow rate of the inner layer liquid is 1-1.5 mL/h.
8. The preparation method of the flame-retardant carbon fiber lithium ion battery separator according to claim 4, characterized in that: in step S22, the volume ratio of carbon dioxide to nitrogen in the carbon dioxide/nitrogen mixed gas is (65-75): (25-35).
9. The preparation method of the flame-retardant carbon fiber lithium ion battery separator according to claim 4, characterized in that: in step S23, the vacuum drying oven has working parameters of drying temperature of 70-80 deg.C and vacuum degree of 0.08-0.1 Mpa.
10. The preparation method of the flame-retardant carbon fiber lithium ion battery separator according to claim 4, characterized in that: in step S4, the temperature for baking and drying is 65-70 ℃.
CN202210706764.7A 2022-06-21 2022-06-21 Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof Active CN115000630B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210706764.7A CN115000630B (en) 2022-06-21 2022-06-21 Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210706764.7A CN115000630B (en) 2022-06-21 2022-06-21 Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof

Publications (2)

Publication Number Publication Date
CN115000630A true CN115000630A (en) 2022-09-02
CN115000630B CN115000630B (en) 2023-09-01

Family

ID=83036722

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210706764.7A Active CN115000630B (en) 2022-06-21 2022-06-21 Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof

Country Status (1)

Country Link
CN (1) CN115000630B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114069154A (en) * 2021-10-08 2022-02-18 天津工业大学 Lithium battery coating diaphragm and preparation method thereof
CN114335896A (en) * 2021-12-29 2022-04-12 江苏厚生新能源科技有限公司 Lithium ion battery diaphragm with high wettability and high flame retardance and preparation method thereof
CN114497887A (en) * 2022-01-26 2022-05-13 江苏厚生新能源科技有限公司 High-flame-retardant lithium ion battery diaphragm and preparation method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114069154A (en) * 2021-10-08 2022-02-18 天津工业大学 Lithium battery coating diaphragm and preparation method thereof
CN114335896A (en) * 2021-12-29 2022-04-12 江苏厚生新能源科技有限公司 Lithium ion battery diaphragm with high wettability and high flame retardance and preparation method thereof
CN114497887A (en) * 2022-01-26 2022-05-13 江苏厚生新能源科技有限公司 High-flame-retardant lithium ion battery diaphragm and preparation method thereof

Also Published As

Publication number Publication date
CN115000630B (en) 2023-09-01

Similar Documents

Publication Publication Date Title
JP7338897B2 (en) Method for producing modified solid electrolyte membrane
CN112151762B (en) Lithium-sulfur battery positive electrode material and preparation method thereof, lithium-sulfur battery positive electrode and preparation method thereof, and lithium-sulfur battery
CN111600000B (en) Carbon nanotube graphene/silicon carbon composite material, and preparation method and application thereof
CN111477816A (en) Lithium ion battery diaphragm and preparation method thereof
CN111180641A (en) Diaphragm with self-crosslinking function and preparation method thereof
CN110600660A (en) Preparation method of surface modified alumina ceramic coating diaphragm
CN114400370A (en) Fabric-reinforced sulfide solid electrolyte and dry preparation method and application thereof
CN114374055A (en) Battery separator with high mechanical strength, high flame retardance and high adhesion and preparation method thereof
Cao et al. Designing polyimide/polyacrylonitrile/polyimide sandwich composite separator for rechargeable lithium-ion batteries
CN115000630A (en) Flame-retardant carbon fiber lithium ion battery diaphragm and preparation method thereof
CN114188665B (en) Lithium ion battery diaphragm with high flame retardance and high mechanical strength and preparation method thereof
CN111244361A (en) Modified polyolefin diaphragm and preparation method and application thereof
CN114696035B (en) Cellulose-based composite diaphragm for lithium ion battery and preparation method thereof
CN111342120A (en) Polymer solid electrolyte, nano composite diaphragm and preparation method thereof, and lithium metal battery
CN114497887B (en) High-flame-retardance lithium ion battery diaphragm and preparation method thereof
CN115663403A (en) High-flame-retardant diaphragm for lithium ion battery and preparation process thereof
CN114006032B (en) Solid polymer electrolyte membrane and manufacturing method thereof
CN114256561A (en) Composite diaphragm for lithium metal battery and preparation method thereof
CN114430092A (en) Lithium ion battery diaphragm based on magnesium hydroxide nanotube and preparation method thereof
CN114243209A (en) Composite diaphragm material and preparation method and application thereof
CN109980166A (en) A kind of biomass nano fibre diaphragm, preparation method and application
CN114976491B (en) High heat-resistant battery diaphragm based on titanium dioxide coaxial tube and preparation method thereof
CN115602999B (en) Composite lithium ion battery diaphragm and preparation method and application thereof
CN115036644B (en) Lithium ion battery diaphragm based on coaxial carbon fibers and preparation method thereof
CN117477168B (en) Isolation film for sodium ion battery and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant