A kind of composite lithium-ion battery diaphragm and preparation method thereof

An ion battery, composite lithium technology, applied in battery pack parts, separators/films/diaphragms/spacers, circuits, etc., can solve the impact of battery safety performance and electrochemical performance, inorganic nanoparticles easily fall off, diaphragm It can improve the electrochemical cycle performance and safety performance, inhibit the collapse of the cathode material structure, and achieve the effect of excellent wettability.

Active Publication Date: 2021-08-03
SOUTH CHINA NORMAL UNIVERSITY
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, most of the separators used in the market are made of polyolefin as the main material. This kind of separator has excellent mechanical strength and chemical stability, and has a wide range of applications, but its melting temperature is low and the wettability of the electrolyte is poor. have a great influence on the safety performance and electrochemical performance of
[0003] In response to this shortcoming, researchers have developed a ceramic coating diaphragm, but the ceramic coating and the polyolefin base film cannot form an organic whole, resulting in some inorganic nanoparticles falling off easily; Close packing, resulting in the limitation of the electrochemical performance of the separator, such as the decrease of the ionic conductivity of the separator

Method used

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  • A kind of composite lithium-ion battery diaphragm and preparation method thereof
  • A kind of composite lithium-ion battery diaphragm and preparation method thereof
  • A kind of composite lithium-ion battery diaphragm and preparation method thereof

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preparation example Construction

[0038] The preparation method of above-mentioned composite lithium-ion battery separator, comprises the following steps:

[0039] 1) adding the tetraethyl orthosilicate-ethanol mixed solution into the ammonia-ethanol-water mixed solution, fully reacting to obtain the nano-silica dispersion;

[0040] 2) Add γ-methacryloxypropyltrimethoxysilane into the nano-silica dispersion liquid, fully react, then separate the solid from the liquid, wash and dry the solid product to obtain vinyl silica nanoparticles ;

[0041] 3) Add 1-vinylimidazole, styrene, initiator and vinyl silica nanoparticles into the solvent, fully react, then separate solid and liquid, wash and dry the solid product to obtain imidazole-based silica nanoparticles ;

[0042] 4) Dispersing imidazole-based silica nanoparticles and organic polymers in a solvent to obtain a casting liquid, then immersing the polyolefin-based film in the casting liquid, fully soaking, taking out and drying to obtain a composite lithium-...

Embodiment 1

[0061] A kind of composite lithium-ion battery diaphragm, its preparation method is as follows:

[0062] 1) Mix 82.8mL ethanol and 8.4mL tetraethyl orthosilicate evenly to obtain tetraethyl orthosilicate-ethanol mixed solution, mix 16.2mL concentrated ammonia water with a mass fraction of 25%, 28.8mL ethanol and 45mL distilled water, Obtain the ammonia water-ethanol-water mixture, and then add the tetraethyl orthosilicate-ethanol mixture into the ammonia-ethanol-water mixture at a constant speed while stirring, and stir at room temperature for 12 hours to obtain a nano-silica dispersion;

[0063] 2) Slowly add 4g of γ-methacryloxypropyltrimethoxysilane dropwise into the nano-silica dispersion, stir at room temperature for 24 hours, centrifuge at high speed, wash the centrifuged solid product with ethanol and distilled water several times, and then Dry at 120°C for 24 hours to obtain vinyl silica nanoparticles;

[0064] 3) Add 0.8mL of 1-vinylimidazole, 0.8mL of styrene, 0.04g...

Embodiment 2

[0073] A kind of composite lithium-ion battery diaphragm, its preparation method is as follows:

[0074] 1) Mix 124.2mL ethanol and 6mL tetraethyl orthosilicate evenly to obtain tetraethyl orthosilicate-ethanol mixed solution, mix 24.3mL concentrated ammonia water with a mass fraction of 25%, 43.2mL ethanol and 67.5mL distilled water, Obtain the ammonia water-ethanol-water mixed solution, and then add the tetraethyl orthosilicate-ethanol mixed solution into the ammonia-ethanol-water mixed solution at a constant speed while stirring, and stir at room temperature for 10 hours to obtain a nano-silica dispersion;

[0075] 2) Slowly add 6 g of γ-methacryloxypropyltrimethoxysilane dropwise into the nano-silica dispersion, stir at room temperature for 30 h, centrifuge at high speed, wash the centrifuged solid product with ethanol and distilled water several times, and then Dry at 110°C for 30 hours to obtain vinyl silica nanoparticles;

[0076] 3) Add 0.8mL of 1-vinylimidazole, 0.8m...

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Abstract

The invention discloses a composite lithium-ion battery diaphragm and a preparation method thereof. The composite lithium-ion battery diaphragm consists of a polyolefin base film and coatings coated on both sides of the polyolefin base film; Silica nanoparticles and organic polymer composition. The preparation method comprises the following steps: 1) preparing a nano-silica dispersion; 2) preparing vinyl silica nanoparticles; 3) preparing imidazole-based silica nanoparticles; 4) forming a functional coating on the surface of the polyolefin base film Floor. The composite lithium-ion battery diaphragm of the invention has excellent wettability, and can remarkably improve the electrochemical cycle performance and safety performance of the lithium-ion battery.

Description

technical field [0001] The invention relates to a composite lithium-ion battery diaphragm and a preparation method thereof, belonging to the technical field of lithium-ion batteries. Background technique [0002] With the rapid development of portable electronic devices and electric vehicles at home and abroad, people have higher and higher requirements for the energy density of lithium-ion batteries, and the increase in battery energy density will inevitably bring about battery safety issues. The separator is an important part of the lithium-ion battery, which plays the role of isolating the positive and negative electrodes and ion conduction, and is an important factor affecting the battery capacity and safety performance. At present, most of the separators used in the market are made of polyolefin as the main material. This kind of separator has excellent mechanical strength and chemical stability, and has a wide range of applications, but its melting temperature is low a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M50/40H01M50/403H01M50/411
CPCH01M50/403H01M50/409H01M50/411Y02E60/10
Inventor 左晓希吴锦华南俊民
Owner SOUTH CHINA NORMAL UNIVERSITY
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