Method for improving hydrophilicity and thermal stability of polypropylene lithium-ion battery separator

A lithium-ion battery, thermal stability technology, applied in the direction of battery components, circuits, electrical components, etc., can solve the problems of easy peeling off of the coated modified coating, difficult operation of graft modification, etc., and achieve the modification method Simple, simple experimental operation, prevent shrinkage effect

Active Publication Date: 2014-08-20
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is: in the modification method of the hydrophilicity and thermal stability of the diaphragm at present, there is difficulty in grafting modification operation; the shortcoming that the modified coating is easy to fall off, in order to solve this technical problem , the technical scheme adopted in the present invention is:

Method used

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  • Method for improving hydrophilicity and thermal stability of polypropylene lithium-ion battery separator
  • Method for improving hydrophilicity and thermal stability of polypropylene lithium-ion battery separator
  • Method for improving hydrophilicity and thermal stability of polypropylene lithium-ion battery separator

Examples

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Embodiment 1

[0041] The monomer diallyl dimethyl ammonium chloride (4.5g) was added in distilled water (30mL), and the initiator ammonium persulfate (APS, the amount of the initiator accounted for 1% of the monomer mass) was added to the distilled water, And react at 70°C for 10 hours to obtain a cationic polyelectrolyte (homopolymer of diallyldimethylammonium chloride) solution;

[0042] Add monomer acrylic acid (4.5g) to distilled water (30mL), add initiator ammonium persulfate (APS, the amount of initiator accounts for 1% of monomer mass) to distilled water, and react at 70°C for 10h, During the reaction, by adding 1mol / L sodium hydroxide solution to the system, the final pH value of the reaction system was adjusted to be 7 to obtain an anionic polyelectrolyte (acrylic acid-sodium acrylate copolymer) solution;

[0043] Pretreatment: the original polypropylene microporous membrane (infrared spectrum as attached figure 1 The spectral line corresponding to the "original film" in the middl...

Embodiment 2

[0047] Get 4.5g of the total mass of diallyldimethylammonium chloride and acrylamide, dissolve it in 30mL of water, add 0.045g (accounting for 1% of the total monomer mass) initiator ammonium persulfate to the system at 70°C After reacting for 10 hours, a cationic polyelectrolyte (copolymer of diallyldimethylammonium chloride and acrylamide) solution was prepared. Wherein, the ratio of the amount of diallyldimethylammonium chloride monomer to the amount of acrylamide monomer is 7:1, and the consumption is 4.2g and 0.3g respectively;

[0048] Take 4.5 g of the total mass of acrylic acid and acrylamide, add it to 30 mL of distilled water, add 0.045 g of initiator ammonium persulfate (accounting for 1% of the total mass of the monomer) and react at 70 ° C for 10 h to prepare an anionic polyelectrolyte (acrylic acid- Acrylamide copolymer) solution, wherein, the ratio of the amount of acrylic acid monomer and acrylamide monomer is 9:1, and the consumption is respectively 4.0g and 0...

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Abstract

Aiming at the problem that hydrophilicity and thermal stability of a polypropylene lithium-ion battery separator are poor, the invention provides a method for layer-by-layer self-assembly of polyelectrolyte on the surface of a separator so as to improve the hydrophilicity and thermal stability of the polypropylene lithium-ion battery separator. According to the technical scheme, an aqueous solution polymerization method is adopted for respectively preparing anion polyelectrolyte containing an anion structural unit and cation polyelectrolyte containing a cation structural unit, and a pretreated polypropylene separator is repeatedly and alternately soaked in two polyelectrolyte solutions, so that macromolecule polyelectrolyte is self assembled onto the surface of the polypropylene separator under the action of an electrostatic force; the polypropylene lithium-ion battery separator prepared by adopting the method provided by the invention has high hydrophilicity and thermal stability, a static water contact angle is as low as 30 degrees; after the polypropylene lithium-ion battery separator is treated for 4 hours at the temperature of 130 DEG C, thermal shrinkage of the polypropylene lithium-ion battery separator is about 15% only; the method is easy to operate and strong in practicability, the defects of chemical modification and a general coating method are overcome, and the method disclosed by the invention can be put into industrial production.

Description

technical field [0001] The invention belongs to the field of preparation of polymer composite functional films, and in particular relates to a process for improving the hydrophilicity and thermal stability of polypropylene lithium-ion battery separators. Background technique [0002] Lithium-ion battery separator is a polymer microporous membrane material located between the positive and negative electrodes of the lithium-ion battery. Allow the ions in the electrolyte to pass freely between the positive and negative electrodes to keep the electrochemical reactions of the battery orderly and reversible. [0003] Polypropylene has the advantages of good chemical stability, heat resistance, acid and alkali resistance, high mechanical strength, and low price. It is a polymer membrane material with superior performance. Polypropylene separators prepared by melt stretching and thermally induced phase separation have also attracted increasing attention and have been widely used in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/42C08J9/40H01M2/16H01M50/403H01M50/417H01M50/491
CPCY02E60/10
Inventor 蒋姗李夏倩马洁丁永红俞强
Owner CHANGZHOU UNIV
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