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Preparation method and application of polyolefin/nanocrystal cellulose composite diaphragm

A technology of nanocrystals and composite diaphragms, applied in the direction of separators/films/diaphragms/spacers, electrical components, circuits, etc., can solve the complex phase inversion method, the composite strength of the diaphragm, the inorganic coating is easy to fall off, and cannot meet the needs of lithium batteries. To achieve the effect of improving puncture strength and tensile strength, ensuring ionic conductivity, and improving hydrophilicity

Inactive Publication Date: 2015-12-23
XUCHENG FUJIAN SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Such as German Degussa (Degussa) company disclosed a patent No. US20110206971A preparation method of a Separion ceramic diaphragm, that is, composite alumina or other inorganic substances on the cellulose non-woven fabric, Separion ceramic diaphragm reflects the cellulose is not easy to heat The characteristics of deformation, no shrinkage and melting phenomenon at 200 ° C, can improve the safety of the power battery, but the phase inversion method involved in the preparation process is more complicated, the cost is high, and the composite strength inorganic coating of the separator is easy to fall off, thus cause safety hazard
In addition, Chinese invention patent CN101710614B discloses a mesoporous nanoparticle-modified lithium battery diaphragm, Chinese invention patent CN102064301A discloses a manufacturing method of a porous multilayer composite diaphragm for lithium batteries and the prepared diaphragm, and the U.S. invention patent US20110171523A discloses a polyolefin ceramic separator for lithium-ion batteries. These patents all disclose adding inorganic particles or heat-resistant resins to improve the heat resistance of the film during the extrusion and stretching of the polyolefin separator. These methods The requirements for equipment are high, which increases the cost. Due to the existence of inorganic particles, the basic properties of the membrane such as air permeability, porosity, pore size, and thickness cannot be well controlled within a certain range, so it cannot be effectively used. , cannot meet the needs of the high-end field of lithium batteries

Method used

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  • Preparation method and application of polyolefin/nanocrystal cellulose composite diaphragm
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  • Preparation method and application of polyolefin/nanocrystal cellulose composite diaphragm

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preparation example Construction

[0036] A preparation method of polyolefin / nanocrystalline cellulose composite diaphragm, which comprises the following steps:

[0037] (1) Base membrane pretreatment

[0038] The polyolefin microporous membrane is used as the base membrane, and the base membrane is soaked in an aqueous solution of catechol derivatives, and active groups are introduced into the surface of the base membrane and the micropores, and then the attachments on the membrane surface are washed away with distilled water, and dried naturally. obtain a modified porous membrane;

[0039] (2) Coating treatment of modified porous membrane

[0040] First immerse the modified porous membrane in the polyelectrolyte aqueous solution, soak it, take it out and soak it with deionized water, then immerse it in the nanocrystalline cellulose sodium dispersion, soak it, take it out and soak it with deionized water, so that the modified porous membrane A coating is formed on the surface of the membrane; the above steps...

Embodiment 3

[0066] A preparation method of polyolefin / nanocrystalline cellulose composite diaphragm, which comprises the following steps:

[0067] 1) Preparation of nanocrystalline cellulose: Take 10 g of microcrystalline cellulose and place it in a 250 mL beaker, slowly add 120 mL of sulfuric acid with a concentration of 64%, heat to 45 ° C, stir for 30 min, and dilute with 10 times the amount of deionized water The reaction solution was used to terminate the hydrolysis reaction; the suspension in the reaction solution was transferred to a centrifuge tube, and centrifuged at a speed of 6000 rpm for 10 min to obtain the supernatant and sediment; the supernatant was removed; the sediment was washed with deionized water, and then Transfer the suspension produced by washing to a centrifuge tube for centrifugation; repeat the washing and centrifugation steps 4 times to obtain a washed solution with a pH of 2; then put the washed solution with a pH of 2 into a dialysis bag and dialyze with deio...

Embodiment 4

[0073] A preparation method of polyolefin / nanocrystalline cellulose composite diaphragm, which comprises the following steps:

[0074]1) Preparation of nanocrystalline cellulose: Take 10 g of microcrystalline cellulose and place it in a 250 mL beaker, slowly add 120 mL of sulfuric acid with a concentration of 64%, heat to 30 ° C, stir for 20 min, and dilute with 10 times the amount of deionized water The reaction solution was used to terminate the hydrolysis reaction; the suspension in the reaction solution was transferred to a centrifuge tube, and centrifuged at a speed of 6000 rpm for 10 min to obtain the supernatant and sediment; the supernatant was removed; the sediment was washed with deionized water, and then Transfer the suspension produced by washing to a centrifuge tube for centrifugation; repeat the washing and centrifugation steps 3 times to obtain a washed solution with a pH of 1; then put the washed solution with a pH of 1 into a dialysis bag and dialyze with deion...

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Abstract

The invention relates to the field of diaphragm materials and particularly relates to a preparation method and application of a polyolefin / nanocrystal cellulose composite diaphragm. The preparation method comprises the following steps: (1) preparing a nanocrystal cellulose sodium dispersion liquid; (2) performing surface pretreatment on a substrate membrane; and (3) performing coating treatment on a modified porous membrane. The polyolefin / nanocrystal cellulose composite diaphragm is applied to the field of lithium ion batteries. The length of nanocrystal cellulose is regulated by virtue of changing the formula of acid hydrolysis, so that the porosity and ionic conductivity of the composite diaphragm are improved. By virtue of applying an LBL technology, the thickness of the composite diaphragm can be changed by virtue of regulating the times of coating the surface of the modified porous membrane, and the nanocrystal cellulose has favorable mechanical strength, so that the puncture-resistant strength and tensile strength of the composite diaphragm and the heat resistance of the substrate membrane are greatly improved.

Description

technical field [0001] The invention relates to the field of diaphragm materials, in particular to a preparation method and application of a polyolefin / nanocrystalline cellulose composite diaphragm. Background technique [0002] Lithium-ion batteries are considered to be one of the most promising forms of new energy power due to their excellent electrical properties such as high energy density, long cycle life, and high voltage, and have become a research hotspot in today's second-generation batteries. Computers, cameras, video cameras, electric vehicles, electric bicycles, large power supplies and other fields. In the structure of lithium batteries, although the separator does not participate in the battery reaction, it is one of the key inner components. The lithium-ion battery separator is generally a porous polymer film, which connects and separates the positive and negative electrode materials. It is an electronic insulator, but allows lithium ions to pass through quic...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M50/403H01M50/417H01M50/44H01M50/491
CPCH01M50/409H01M50/403Y02E60/10
Inventor 李文谨陈洪隆胡洪海刘峥赵静
Owner XUCHENG FUJIAN SCI & TECH
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