Modified silicon dioxide and high-property lithium ion battery diaphragm and application thereof

A lithium-ion battery and silicon dioxide technology, which is applied in the direction of silicon dioxide, silicon oxide, battery pack components, etc., can solve problems such as complex process, affecting battery capacity, and thick diaphragm, so as to achieve simple preparation process and improve ion The effect of permeability

Inactive Publication Date: 2013-08-07
中科广化(重庆)新材料研究院有限公司 +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process of "thermally induced phase separation" method (also called wet method) is more complicated than that of "hard elastic" method, and diluent needs to be added and removed, so the production cost is relatively high and may cause secondary pollution. At present, this method is adopted in the world. Japan's Asahi Kasei, Tonen, etc.
[0010] However, the main problems of polyolefin separators for lithium-ion batteries prepared by dry methods are: 1) the thickness of the separator is relatively thick (single-layer film is generally greater than 15μ), which directly affects the capacity of the battery, 2) due to the porosity and Pore ​​structure and other reasons lead to low ion permeability, large internal resistance of the battery, etc., which affect the cycle charge and discharge performance of the battery, etc. Potential battery safety hazards

Method used

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  • Modified silicon dioxide and high-property lithium ion battery diaphragm and application thereof
  • Modified silicon dioxide and high-property lithium ion battery diaphragm and application thereof
  • Modified silicon dioxide and high-property lithium ion battery diaphragm and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] A modified silica prepared by the following method:

[0062] (1) Disperse 20g of silicon dioxide with a particle size of 90nm in 600ml of anhydrous toluene, add 100g of aminopropyltriethoxysilane, fill with nitrogen and heat to boiling, then reflux at constant temperature (105°C) for 48h, and then sequentially Wash with anhydrous toluene and anhydrous acetone, and dry in vacuum to obtain aminated silicon dioxide;

[0063] (2) Disperse 15 g of aminated silicon dioxide in 300 ml of anhydrous toluene, add 80 g of triethylamine, and add 20 g of 2-bromoisobutyryl bromide dropwise in an ice-water bath. Then cancel the ice-water bath and allow the reaction system to naturally warm up to 20°C for 4 hours, and then wash with acetone, water, and acetone precipitation successively. Vacuum drying, obtains the silicon dioxide that has ATRP initiator on the surface;

[0064] (3) in the round-bottomed flask of 100ml, the surface that adds 30g (0.30mol) methyl methacrylate, 12.5g (2m...

Embodiment 2

[0070] A modified silica prepared by the following method:

[0071] (1) Disperse 25g of silicon dioxide with a particle size of 300nm in 600ml of anhydrous toluene, add 100g of aminopropyltriethoxysilane, heat to boiling after filling with nitrogen, then reflux at constant temperature (105°C) for 48h, and then sequentially Wash with anhydrous toluene and anhydrous acetone, and dry in vacuum to obtain aminated silicon dioxide;

[0072] (2) Disperse 20 g of aminated silicon dioxide in 300 ml of anhydrous toluene, add 80 g of pyridine, and drop in 20 g of 2-bromoisobutyryl bromide in an ice-water bath. Then cancel the ice-water bath and allow the reaction system to naturally warm up to 30°C for 4 hours, and then use acetone, water, and acetone for precipitation and washing in sequence. Vacuum-dried to obtain silicon dioxide with ATRP initiator on the surface;

[0073] (3) Add 42.7g (0.30mol) butyl methacrylate, 10g (1.60mmol) of silicon dioxide, 1.3077g (3.20mmol) of ATRP initi...

Embodiment 3

[0079] A polyolefin microporous diaphragm for a lithium ion battery, prepared by the following method:

[0080] (1) Mix 100g of the modified silicon dioxide prepared in Example 1 with 125g of ultra-high molecular weight polyethylene (the intrinsic viscosity measured in decahydronaphthalene at 135°C is 22dL / g), and then add 1250g of ordinary polyethylene resin for co- Mixing and granulation to obtain modified masterbatch;

[0081] (2) Melt, blend and extrude 5000g of modified masterbatch and 45000g of polyethylene resin through a twin-screw (or single-screw) extruder, with a melt temperature of 200°C and a melt draw ratio of 400 times, and crystallize under the stress field , forming a diaphragm with a hard elastic structure;

[0082] (3) Use a uniaxial stretching machine to continuously stretch the membrane, the stretching ratio is 2 times, and the stretching temperature is 100°C. After stretching, it is heat-set at 125°C for 10 minutes to prepare polyolefin for lithium-ion b...

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Abstract

The invention belongs to the field of lithium ion battery diaphragm materials and discloses modified silicon dioxide and a lithium ion battery polyolefin microporous diaphragm. The diaphragm is prepared by the following method: blending modified silicon dioxide with polyolefin having high / ultrahigh molecular weight, adding common polyolefin, and pelleting so as to obtain modified masterbatch; mixing the modified masterbatch with polyolefin and then carrying out melt blending and extrusion so as to form a diaphragm with a hard elastic structure; and carrying out continuous tension on the diaphragm, and then carrying out heat shaping at the temperature of 100-150 DEG C so as to obtain the lithium ion battery polyolefin microporous diaphragm. According to the invention, the thickness of the lithium ion battery polyolefin microporous diaphragm is relatively low (less than 15mu m); the strength of the diaphragm is better (the longitudinal breaking strength is larger than 100MPa, the transversal breaking strength is about 8MPa, and breaking elongation is 50%); the porosity and pore structure of the diaphragm are adjustable (the porosity is more than 50%, and the pore diameter is 0.1-1mum); and the thermal shrinkage factor of the diaphragm is smaller (less than 5%). According to the invention, the defect and lack of the existing dry preparation technology of the lithium ion battery diaphragm are overcome.

Description

technical field [0001] The invention belongs to the field of diaphragm materials for lithium ion batteries, and in particular relates to a modified silicon dioxide, a polyolefin microporous diaphragm for lithium ion batteries prepared by the modified silicon dioxide and applications thereof. Background technique [0002] Lithium-ion batteries are widely used in portable electronic products such as mobile phones, notebook computers, camcorders, etc. The development of electric vehicles will also drive greater demand for lithium-ion batteries. Lithium-ion batteries are used in aerospace, navigation, satellites, small It has also been widely used in fields such as medical treatment and military communication equipment. [0003] Lithium-ion batteries are mainly composed of electrodes, electrolytes, and polymer separators. Between the positive and negative electrodes of lithium-ion batteries is a diaphragm material, usually called a polymer diaphragm. As one of the main componen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/12H01M2/16
CPCY02E60/12Y02E60/10
Inventor 胡继文肖定书张干伟李银辉涂园园刘国军胡美龙胡盛逾李妃
Owner 中科广化(重庆)新材料研究院有限公司
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