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Grafting modified high polymer material, and preparation method and application thereof

A polymer material and graft modification technology, which is applied in the field of graft modified polymer materials and its preparation and application, can solve the problem of battery performance degradation, easy electrolyte leakage, affecting lithium ion conductivity and long-term use performance And other issues

Active Publication Date: 2012-05-02
上海世龙科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the poor affinity between the polyolefin diaphragm used in the existing lithium-ion battery and the commonly used ester electrolyte, and the polyolefin diaphragm is too high in crystallinity, and it is difficult to be swollen and coagulated by the electrolyte. Gelling leads to limited electrolyte absorption by the diaphragm, low liquid retention rate, and easy leakage of the electrolyte, which affects the conductivity and long-term service performance of lithium ions; in addition, in the prior art, by coating the polyolefin diaphragm and neutral groups to improve the affinity of the polyolefin microporous membrane, but the performance of the battery after repeated charging and discharging of this kind of separator decreases, the stability is poor, and it also affects the performance of the battery and other defects.

Method used

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  • Grafting modified high polymer material, and preparation method and application thereof
  • Grafting modified high polymer material, and preparation method and application thereof
  • Grafting modified high polymer material, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Select thickness to be 5g polyethylene non-woven fabrics of 50 microns as macromolecule material (number-average molecular weight is 200,000, average pore diameter is 1.7 microns), this polyethylene non-woven fabrics is soaked in by 10g vinyl acetate and 40g ethyl acetate The resulting solution was irradiated to 30kGy with gamma rays produced by a cobalt source in a nitrogen atmosphere, taken out and extracted with ethyl acetate for 2 days in a Soxhlet extractor to obtain a modified PE-g with a grafting rate of 90%. -PVAc non-woven fabric, which is the desired Li-ion separator.

Embodiment 2

[0054] Select the polypropylene non-woven fabric 20g that thickness is 100 microns as macromolecule material (number-average molecular weight is 250,000, and average aperture is 2.5 microns), this non-woven fabric is soaked in by 10g ethyl acrylate and 90g ethyl acetate composition In the solution, irradiate to 20kGy with the ray that electron beam produces in nitrogen atmosphere, take out and extract with acetone in Soxhlet extractor for 2 days, obtain the modified non-woven fabric of ethyl acrylate grafting rate 30%, namely Li-ion separator required.

Embodiment 3

[0056] Select the PVDF microporous membrane 10g that thickness is 40 microns as macromolecule material (the number average molecular weight is 550,000, and aperture is 2 microns on average), utilizes cobalt 60 gamma ray source to irradiate it in air, and irradiation dose is 20kGy. Mix 20g of ethyl methacrylate and 2g of Tween 20 into an emulsion in 78g of water, immerse the irradiated PVDF microporous membrane into the emulsion, raise the temperature to 60°C for 6 hours under nitrogen protection, and take it out. Extract with acetone for 2 days to obtain a modified PVDF-g-PEMA microporous membrane with a graft rate of 70%, which is the desired lithium ion separator.

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Abstract

The invention discloses a grafting modified high polymer material which is a high polymer micro-porous membrane or a high polymer non-woven fabric with a graft chain, wherein the graft chain is a polymeric chain of more than one monomer; the polymeric chain is a homo-polymer chain formed by the same monomer or a random copolymer chain formed by different monomers; and the monomer is provided with at least one C=C double bond and at least one ether group or a group shown in the formula I. The invention overcomes the defect that the affinity of the polyolefin micro-porous membrane is improved by coating the affinity group, but the affinity group is easy to drop in the process of using the lithium ion battery, and provides the grafting modified polymer material and a preparation method thereof. The high polymer material is especially suitable for serving as the lithium ion battery separator, reduces the crystallinity of the polyolefin separator and has good affinity for the ester organic electrolyte, and at the same time, the polymer material is not easy to drop from the separator in the use process and can lengthen the use performance of the battery.

Description

technical field [0001] The invention relates to a graft modified polymer material and its preparation method and application. Background technique [0002] Lithium-ion batteries have many advantages such as high working voltage, high energy density, wide working temperature range, small self-discharge, long cycle life, and no environmental pollution. It has become a hot spot in the research and development and application of secondary batteries in the world today. It is not only widely used in mobile communication products and portable electronic products, but also has a promising application in power vehicles. [0003] Lithium-ion batteries are mainly composed of positive electrode, negative electrode, electrolyte and separator. Among them, the battery separator is an important component. Its main function is to separate the positive and negative electrodes, prevent the short circuit between the positive and negative electrodes, and provide the necessary lithium ion channe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J7/18D06M14/18D06M14/28D06M14/32D06M14/34H01M2/16C08L27/16C08L23/06C08L81/06H01M50/411
CPCY02E60/12Y02E60/10
Inventor 李景烨李林繁邓波虞鸣
Owner 上海世龙科技有限公司
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