Composite diaphragm for lithium ion battery and preparation method thereof

A technology of lithium-ion batteries and composite diaphragms, which is applied to battery components, circuits, electrical components, etc., can solve the problems of high crystallinity of pure PVDF materials, poor stability of bound electrolytes, and low ion conductivity, so as to improve comprehensive performance , low production cost, simple and safe operation

Inactive Publication Date: 2012-01-18
JIANGSU HUAFU STORAGE NEW TECH DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, pure PVDF material has high crystallinity and poor stability of bound electrolyte,

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example

[0019] example 1:

[0020] 1) Mix 4g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) and 1g of polydimethylsiloxane (PDMS) at room temperature, and add 10g of dimethyl phthalate (DMP) ) And 10g of N,N-dimethylacetamide (DMAc) diluent, stirred at 60°C for 6 hours to obtain a uniform mixed system.

[0021] 2) Add 0.25g of 1,2-propanediol and 0.25g of glycerol dispersant to the mixed system, stir at room temperature for 2 hours, and further disperse and dilute the blended materials to obtain a blend of PVDF-HFP and PDMS with uniform properties Things.

[0022] 3) Coat the PVDF-HFP / PDMS blend uniformly on a glass plate with a film thickness of 80μm. After standing at room temperature for 10 seconds, wash with 25g of 10% (volume percentage) ethanol solution for three times, and then at room temperature The glass plate was immersed in 75g of 10% (volume percentage) ethanol solution for 48 hours to remove the diluent and dispersant, and then vacuum dried at 40°C for 48...

Example

[0028] Example 2:

[0029] 1) Mix 4.5g PVDF-HFP and 0.5g PDMS uniformly at room temperature, add 15g DMAc diluent, and stir at 60°C for 6 hours to obtain a homogeneous mixed system.

[0030] 2) Add 0.5g of isopropanol or glycerol dispersant to the mixing system, stir at room temperature for 2 hours, and further disperse and dilute the blended materials to obtain a PVDF-HFP and PDMS blend with uniform properties.

[0031] 3) Coat the blend of PVDF-HFP and PDMS uniformly on the glass plate with a thickness of 100μm. After standing at room temperature for 15 seconds, wash with 35g 10% (volume percentage) ethanol solution for three times, and then at room temperature. The glass plate was immersed in 75g of 10% (volume percentage) ethanol solution for 48 hours to remove the diluent and dispersant, and then vacuum dried at 40°C for 48 hours to obtain a PVDF-HFP and PDMS composite diaphragm for lithium ion batteries.

[0032] 4) After testing, the characteristics of the composite diaphragm m...

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Abstract

The invention relates to the research field of lithium ion batteries, and discloses a composite diaphragm for lithium ion batteries and a preparation method thereof. Firstly, PVDF-HFP and PDMS are dissolved in a diluent to obtain a mixed system with uniform characters; secondly, a dispersant is added into the mixed system to obtain a dispersion system; finally, the mixture of PVDF-HFP and PDMS is prepared into a film, and the film is extracted by an extractant and is dried to obtain a porous PVDF-HFP and PDMS composite diaphragm. The composite diaphragm prepared by the invention has high a liquid absorption rate, conductivity, and uniform pore distribution. The composite diaphragm has an electrolyte absorptivity of 175-185%, room temperature conductivity of 1.3 mS/cm, and porosity of 60%-75%.

Description

technical field [0001] The invention relates to the research field of lithium ion batteries, in particular to a preparation method of a PVDF-HFP / PDMS composite diaphragm for lithium ion batteries. Background technique [0002] Because of its high specific energy, long cycle life, and no memory effect, lithium-ion batteries are widely used and have become a hot research field for secondary power supplies. The main function of the lithium-ion battery separator is to isolate the positive and negative electrodes and prevent electrons from passing through, but to allow ions in the electrolyte to pass freely between the positive and negative electrodes. [0003] With the continuous development of electronic equipment in the direction of portability, the lithium-ion battery used in it needs to have the characteristics of high energy density and high capacity. Different from the first-generation lithium-ion battery liquid electrolyte commonly used at present, the second-generation ...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/18
CPCY02E60/12Y02E60/10
Inventor 吴战宇顾立贞朱守圃董志成周寿斌于尊奎代云飞
Owner JIANGSU HUAFU STORAGE NEW TECH DEV
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