A negative electrode binder and a method for preparing a silicon-based negative electrode sheet containing the binder

A binder and negative electrode technology, applied in the direction of negative electrodes, structural parts, battery electrodes, etc., can solve the problems of battery capacity attenuation, loss of electrical contact, damage to electrode structure, etc., to buffer volume expansion effect, improve adhesion, Effect of improving cycle performance

Active Publication Date: 2022-06-14
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Claims
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Problems solved by technology

At present, the theoretical specific capacity of the most widely used graphite anode material in commercialization is only 372mAh / g, which can no longer meet the development needs of high energy density lithium-ion batteries. In addition, its lithium intercalation potential is very close to the deposition potential of lithium, which brings huge security risk
[0003] In recent years, a lot of work has focused on silicon-based anode materials, because of the ultra-high theoretical capacity of silicon (4200mAh / g), but the defect of nano-silicon as an anode material is that the battery is accompanied by a large volume effect during charging and discharging. The pulverization of silicon particles, thus losing electrical contact with the conductive agent, destroys the entire electrode structure, resulting in attenuation of battery capacity and extremely poor cycle performance

Method used

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  • A negative electrode binder and a method for preparing a silicon-based negative electrode sheet containing the binder

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preparation example Construction

[0027] A negative binder of the present invention, prepared by the following method:

[0028] (1) The guar bean gum is dissolved in ethanol solution for dispersion, wherein the guar bean gum and the ethanol solution mass ratio of 1:3.3 ~ 5, to give the guar bean gum dispersion, to the guar bean gum dispersion liquid added cellulose ether, the cellulose ether and the quality ratio of the guar bean gum used is 0.2 ~ 0.6: 1, at 40 ~ 60 ° C reaction 30 ~ 60min, to give guar bean gum mixed solution;

[0029] (2) The guar bean gum mixed solution and functional monomers are mixed and stirred and placed under γ rays for irradiation, the dose rate of irradiation is 1~ 2.5kGy / h, the time is 12 ~ 24h, the irradiation product is washed, wherein the functional monomer is acrylic acid, 2-ethylacrylic acid, 2-propylacrylic acid, 2-butylacrylic acid at least one; Wherein the amount of functional monomer added is 1 to 5% of the amount of guar soybean gum used in step (1);

[0030] (3) The irradiat...

Embodiment 1

[0036] Preparation of negative binders:

[0037] (1) The guar bean gum is dissolved in ethanol solution for dispersion, wherein the guar gum and the mass ratio of the ethanol solution is 1:3.3, to obtain a guar bean gum dispersion, to the guar bean gum dispersion was added to the cellulose ether, the cellulose ether and the quality ratio of the guar bean gum used is 0.4:1, react at 60 ° C for 45min, to give a guar bean gum mixed solution;

[0038] (2) The guar bean gum mixed solution was mixed with acrylic acid for 10 min and then placed under γ radiation for irradiation, the dose rate of irradiation was 1kGy / h, the time was 24h, and the irradiation product was washed; Wherein the amount of acrylic acid is 1% of the amount of guar gum used in step (1);

[0039] (3) The irradiation product obtained after washing is mixed and stirred with sodium tetraborate, and the reaction is 30min to obtain a negative electrode binder.

[0040] Silicon-based negative electrode sheet prepared by t...

Embodiment 2

[0045] Preparation of negative binders:

[0046] (1) The guar bean gum is dissolved in ethanol solution for dispersion, wherein the guar bean gum and the ethanol solution mass ratio is 1:4, to obtain a guar bean gum dispersion, to the guar bean gum dispersion was added to the cellulose ether, the cellulose ether and the quality ratio of the guar bean gum used is 0.3:1, reacted at 50 ° C for 50min, to give a guar bean gum mixed solution;

[0047] (2) The guar bean gum mixed solution and methacrylic acid were mixed and stirred for 10 min and then placed under γ radiation for irradiation, the dose rate of irradiation was 1.5kGy / h, the time was 16h, and the irradiation products were washed; Wherein the amount of methacrylic acid added is 5% of the amount of guar gum used in step (1);

[0048] (3) The resulting product of the irradiation that has been washed is mixed and stirred with sodium tetraborate, and the reaction is 40min to obtain a negative binder.

[0049] Silicon-based negat...

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Abstract

The invention discloses a negative electrode binder, which is prepared by the following method: mix and stir a guar gum mixed solution and a functional monomer, place it under gamma rays for irradiation, and wash the product obtained from the irradiation. Obtain the negative electrode binder; Wherein, the guar gum mixed solution is made according to the following steps: first, the guar gum is dissolved in an ethanol solution and dispersed to obtain a guar gum dispersion; Add cellulose ether to the bean gum dispersion and react at 40-60°C for 30-60 minutes to obtain a guar gum mixed solution. In the present invention, the guar gum is first pretreated by cellulose ether, and then modified by irradiation to maximize the bonding performance of the guar gum. Vacuum treatment is used in the process of preparing pole pieces to solve the problem of silicon volume. Swelling effect, thereby improving the cycle performance of the negative electrode sheet, and significantly improving the Coulombic efficiency of the lithium-ion battery.

Description

Technical field [0001] The present invention belongs to the field of anode material technology, specifically relates to a negative electrode binder and a method for preparing a silicon-based negative electrode sheet comprising the binder. Background [0002] With the development of portable electronic devices and electric vehicles, people's energy density requirements for lithium-ion batteries are also increasing. At present, the theoretical specific capacity of the most widely commercially used graphite anode material is only 372mAh / g, which can no longer meet the development needs of high-energy density lithium-ion batteries, in addition, its embedded lithium potential is very close to the deposition potential of lithium, which brings huge safety risks to the battery. [0003] In recent years, a lot of work has focused on silicon-based anode materials, because of the ultra-high theoretical capacity of silicon (4200mAh / g), but the defect of nano-silicon as an anode material is t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/1395H01M4/38H01M10/0525C08F251/00C08F220/06C08F220/04C08F2/46
CPCH01M4/621H01M4/1395H01M4/386H01M4/622H01M10/0525C08F251/00C08F2/46H01M2004/027C08F220/06C08F220/04Y02E60/10
Inventor 林少雄谢李昭赵宇飞辛利君梁栋栋李道聪
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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