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Self-supporting polymer membrane material for lithium ion secondary battery and preparation method thereof

A polymer film and secondary battery technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problem of poor ability of microporous film to absorb and retain electrolyte, poor ability of microporous film to absorb and retain liquid, Poor mechanical properties, etc.

Active Publication Date: 2020-07-07
GUIZHOU INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The main problems of polyolefin microporous membranes: First, the microporous membranes have poor liquid absorption and liquid retention capabilities. PP, PE or their mixtures are non-polar materials, which have poor affinity with highly polar electrolyte solutions. , resulting in the poor ability of the microporous membrane to absorb and retain electrolyte, and the liquid absorption and liquid retention capacity of the microporous membrane are closely related to the charge-discharge cycle life of the battery; the second is that the microporous membrane Poor thermal stability, because the polyolefin microporous membrane is mechanically stretched to form pores, or mechanically stretched and then extracted with an organic solvent to form pores, and the microporous membrane is heat-set. This preparation process makes the polyolefin microporous membrane There is residual stress inside the porous membrane, which has a shape memory effect
[0007] However, the ionic polymer film uses acrylate as the first monomer, and its glass transition temperature is low, and its mechanical properties are poor. It is necessary to add a film-forming agent during the preparation process. The lithium ion transport channel is mainly the ion polymer film absorbing electrolysis Colloidal particle-to-colloidal particle-to-colloidal interfacial voids for transport
The added film-forming agent only provides mechanical support and does not contribute to the electrochemical performance of the polymer electrolyte membrane

Method used

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  • Self-supporting polymer membrane material for lithium ion secondary battery and preparation method thereof
  • Self-supporting polymer membrane material for lithium ion secondary battery and preparation method thereof
  • Self-supporting polymer membrane material for lithium ion secondary battery and preparation method thereof

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preparation example Construction

[0040] The interpenetrating network ionic polymer membrane provided by the invention is prepared by the following method:

[0041] (1) Synthesis of polymer colloidal ionic emulsion with interpenetrating network structure: Mix the polymerization reaction monomer A, crosslinking agent, and reactive emulsifier (in any order) evenly, and then add an initiator to polymerize to obtain polymer colloidal emulsion 1 #;

[0042] (2) On the basis of 1#, add polymer reaction monomer B and crosslinking agent (in any order), add initiator polymer reaction to obtain polymer colloidal emulsion 2# with interpenetrating network structure;

[0043] (3) Coat the polymer colloid emulsion 2# on the plastic base tape, peel off after drying.

[0044] As a preferred scheme of the present invention, the polymerization reaction monomer A is an acrylic ester with a homopolymer glass transition temperature lower than 20°C, B is an acrylic ester with a homopolymer glass transition temperature higher than ...

Embodiment 1

[0052] In a four-port reactor with condensed water, add 10g sodium allyl sulfonate (SAS), 10g crosslinking agent methylenebisacrylamide (MBA), blow nitrogen to remove oxygen, stir for 1h, add 0.8g persulfuric acid Ammonium initiates polymerization, raise the temperature to 70°C, add 90g of 2-ethylhexyl acrylate (2-EHA) dropwise, and react for 6 hours, then cool down to 60°C, then add 20g of methyl methacrylate (MMA) and 0.5g Allyl glycidyl ether (AGE), while adding 0.2 g of ammonium persulfate to continue polymerization for 10 hours, to obtain a white polymer colloidal emulsion with an interpenetrating network structure.

[0053]The prepared polymer colloidal emulsion with an interpenetrating network structure was cast into a film and coated on a PET base tape, and after drying the water, an ionic polymer film with a thickness of 20-25 μm was obtained with an interpenetrating network structure. The particle size range of observed colloidal particles is 80~200nm.

[0054] fig...

Embodiment 2

[0058] In a four-port reactor with condensed water, add 10g sodium allyl sulfonate (SAS), 10g crosslinking agent methylenebisacrylamide (MBA), blow nitrogen to remove oxygen, stir for 1h, add 0.8g persulfuric acid Ammonium initiates polymerization, heat up to 70°C, add 90g of 2-ethylhexyl acrylate (2-EHA) dropwise, and react for 6 hours, then cool down to 60°C, then add 20g of acrylonitrile (AN) and 0.5g of allyl Glycidyl ether (AGE), while adding 0.2g ammonium persulfate to continue polymerization for 10 hours, to obtain a white polymer colloidal emulsion with an interpenetrating network structure.

[0059] The prepared polymer colloidal emulsion with an interpenetrating network structure was cast into a film and coated on a PET base tape, and after drying the water, an ionic polymer film with a thickness of 20-25 μm was obtained with an interpenetrating network structure. The particle size range of observed colloidal particles is 80~200nm.

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Abstract

The invention discloses a self-supporting polymer membrane material, a preparation method of the self-supporting polymer membrane material and a lithium secondary battery, which belongs to the technical field of the manufacturing of lithium batteries. The invention provides an ion polymer membrane material of an interpenetrating network structure. The ion polymer membrane material is formed by continuously interpenetrating networks obtained by respectively cross-linking a cross-linked polymer I with a sulfonate group and a cross-linked polymer II. The membrane is formed by colloid particles of the interpenetrating network structure and is a non-porous compact membrane, and when the battery is overheated, the diaphragm has no obvious heat shrinkage. In addition, after the ion polymer membrane of the interpenetrating network structure absorbs electrolyte, a penetrating ion transfer route is formed between the colloid particles; and moreover, after the membrane absorbs the electrolyte solution or solvent, the colloid particle structure is still maintained, the close packing structure of the colloid particles increases ion transferring sinuosity, and the electron insulation performance of the electrolyte membrane is improved. Meanwhile, the existence of the interpenetrating network structure improves the mechanical performance of the ion polymer membrane, and the integration of the mechanical performance and electrochemical performance is realized.

Description

Technical field [0001] The invention relates to a diaphragm material used for energy storage devices such as lithium ion secondary batteries and a preparation method thereof, and belongs to the field of lithium battery manufacturing. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, environmental friendliness and no memory effect, and have been widely used in 3C consumer electronics and new energy vehicles. The separator is one of the important components of the battery. Its microporous structure, heat resistance and other physical and chemical properties are closely related to the performance of the battery. Lithium-ion batteries have high operating voltages, positive electrode materials with strong oxidizing properties, and negative electrode materials with strong reducing properties. Therefore, lithium-ion battery separator materials should have good compatibility with highly electrochemically active positive and negative el...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M2/14C08L33/20C08L41/00C08L25/08C08L33/12C08L33/14
CPCC08L25/08C08L33/12C08L33/20C08L2205/02C08L2205/04H01M50/403H01M50/411C08L41/00C08L33/14Y02E60/10
Inventor 马先果邹树良刘浪郭俊江唐安江
Owner GUIZHOU INST OF TECH