Composite membrane for lithium ion batteries 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 reducing ceramic grafting rate, complex process operation process, and low grafting rate, so as to improve high temperature thermal stability properties, improve grafting efficiency, and weaken the effect of hydrogen bonds

Active Publication Date: 2014-07-30
DONGFANG ELECTRIC CORP LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are still two shortcomings in the ceramic grafting modification method: one is that the selected monomer has a large steric hindrance and the grafting rate is low; the other is that the process operation is complicated, which is not conducive to industrial production. Ion exchange was also carried out after the neutralization, and the product loss would be caused during the ion exchange process, further reducing the yield
The steric hindrance of the monomer is specifically reflected in the steric hindrance of the benzene ring in sodium benzenesulfonate (also known as the stereo effect: mainly refers to the steric hindrance caused by certain atoms or groups in the molecule being close to each other and the deviation from the normal bond angle. The tension in the molecule) is relatively large, that is, the sodium benzenesulfonate derivatives all contain rigid benzene rings with high tension. When such reagents attack Al as a nucleophile 2 o 3 When the surface hydroxyl group, due to the influence of the larger steric hindrance of the benzene ring connected ...

Method used

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  • Composite membrane for lithium ion batteries and preparation method thereof
  • Composite membrane for lithium ion batteries and preparation method thereof
  • Composite membrane for lithium ion batteries and preparation method thereof

Examples

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preparation example Construction

[0049] A preparation method for a ceramic diaphragm for a lithium-ion battery, comprising the steps of:

[0050] (1) Ceramic surface grafting modification: Under the action of appropriate solvent and dehydrating agent, weakly acidic or neutral ceramic powder (mainly nanometer or submicron oxide powder, such as Al 2 o 3 , SiO 2 、TiO 2 , ferrite and other oxides) and organic monomers or polymers with active hydroxyl, carboxyl sodium sulfonate or sodium carboxylate groups in the side chain or end group, under the action of a dehydrating agent, the "grafting to" method is obtained. Branched ceramic powder; or organic monomers with no active groups in the side chains, under the action of coupling agents, polymerize on the surface of ceramics through the "grafting on" method to achieve the purpose of grafting and modifying ceramics, and The grafted ceramic powder is washed to obtain the grafted modified ceramic powder.

[0051] The dehydrating agent is mainly N, N-dicyclohe...

Embodiment 1

[0061] A preparation method for a lithium-ion battery composite diaphragm, comprising the steps of:

[0062] a. Ceramic surface graft modification

[0063] The graft monomer structure is as follows:

[0064]

[0065] Add 10 g of submicron aluminum oxide powder (ceramic powder), 5-40 g of sodium isethionate (SHES), preferably 10-20 g, and 2 g of N,N-bicyclo Hexylcarbodiimide (DCC), HMPS and DCC need to be dissolved in 300 mL isopropanol in advance. N 2 Heat and reflux in a water bath under atmosphere for 4-6 hours to carry out the grafting reaction. After the grafting reaction is completed, the product is centrifugally washed with ethanol and acetone for 3 to 4 times, and then vacuum-dried to constant weight to obtain the grafted modified ceramic Al 2 o 3 .

[0066] b. Preparation of ceramic coating slurry

[0067] Mix the mixed solvent composed of sodium isethionate (SHES) modified ceramics, binder sodium polyacrylate, ethanol and water in a mass ratio of 6:1:5 in a ...

Embodiment 2

[0071] a. Ceramic surface graft modification

[0072] The graft monomer structure is as follows:

[0073]

[0074] Add 10 g of submicron aluminum oxide powder (ceramic powder), 5-40 g of hydroxypropyl sodium methacrylate (HMPS) (preferably 10-20 g) and 2 g of N into the three-necked flask, N-dicyclohexylcarbodiimide (DCC), HMPS and DCC need to be dissolved in 300 mL isopropanol in advance. N 2 Heat and reflux in a water bath under atmosphere for 4-6 hours to carry out the grafting reaction. After the grafting reaction is completed, the product is centrifugally washed with ethanol and acetone for 3 to 4 times, and then vacuum-dried to constant weight to obtain the grafted modified ceramic Al 2 o 3 .

[0075] b. Preparation of ceramic coating slurry

[0076] Stir and mix the mixed solvent composed of hydroxypropyl sodium methacrylate (HMPS) modified ceramics, binder sodium polyacrylate, ethanol and water at a mass ratio of 6:3:20 in a stirring tank or a ball milling tan...

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Abstract

The invention discloses a composite membrane for lithium ion batteries and a preparation method thereof, including a ceramic coating modification method and a ceramic lithium battery membrane. The ceramic protective layer is mainly prepared from a ceramic-adhesive mixture subjected to graft modification by a sodium-sulfonate/sodium-carboxylate-group-containing anionic surfactant. The grafting is completed by using a grafting-to process under the action of a dehydrating agent; the grafting ratio of the ceramic is higher; the high-temperature-resistant large-surface-area nano ceramic is introduced to the conventional PP (polypropylene) membrane surface, the insulativity and electrolyte wettability of the modified ceramic membrane are greatly enhanced; and the membrane has excellent high-temperature heat stability especially at the high temperature of 130 DEG C, 150 DEG C and 180 DEG C. The lithium battery composite membrane avoids the thermal shrinkage of the convention membrane, thereby avoids the thermorunaway in the battery due to thermal shrinkage, and further enhancing the safe reliability of the lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a composite separator for lithium-ion batteries and a preparation method thereof. More specifically, the invention relates to the inclusion of anionic surfactants and the modification and coating of ceramics by grafting, thereby improving A method of dispersion and adhesion of ceramics. Background technique [0002] Lithium-ion batteries have been widely used as power sources for various mobile devices since their commercialization due to their high energy density, high operating voltage, no memory effect, and long cycle life. And it is very likely to become the most important power supply system in the field of energy storage and electric vehicles. However, with the large-scale application of lithium-ion batteries, battery safety issues have become increasingly prominent. [0003] One of the key factors affecting the safety of lithium-ion power batteri...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M50/403H01M50/417H01M50/434H01M50/451
CPCH01M50/446H01M50/403Y02E60/10
Inventor 黄兴兰廖晓东郑威汤勇
Owner DONGFANG ELECTRIC CORP LTD
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