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A high specific capacity silicon-based negative electrode composite binder and a preparation method of a negative electrode sheet containing the binder

A silicon-based negative electrode, high specific capacity technology, applied in structural parts, battery electrodes, electrical components, etc., can solve the problems of short battery cycle life and so on

Active Publication Date: 2018-07-27
WANXIANG 123 CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The composite binder of the present invention can solve the technical problem of short battery cycle life caused by the huge volume change of existing silicon-based negative electrode materials during the process of intercalation and extraction of lithium ions

Method used

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  • A high specific capacity silicon-based negative electrode composite binder and a preparation method of a negative electrode sheet containing the binder

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Embodiment 1

[0029] A high specific capacity silicon-based negative electrode composite binder, including sodium carboxymethyl cellulose, polyacrylic acid and styrene-butadiene rubber. Wherein the mass ratio of sodium carboxymethyl cellulose, polyacrylic acid and styrene-butadiene rubber is 2:1:3.

[0030] A method for preparing a negative electrode sheet containing a high specific capacity silicon-based negative electrode composite binder, comprising the following steps:

[0031] 1) Add 3.3 parts of sodium carboxymethylcellulose powder to deionized water and stir at a speed of 3000rpm. After stirring evenly, add 1.7 parts of polyacrylic acid to make the solid content of the liquid 15wt%, and stir at 800rpm for 30 minutes. Defoaming to obtain glue.

[0032] 2) Add 4 parts of Super P conductive agent to the above glue solution and stir at 3000rpm for 2 hours to prepare a conductive solution.

[0033] 3) Add 51 parts of SiO negative electrode powder to the above conductive liquid, stir at ...

Embodiment 2

[0040] A high specific capacity silicon-based negative electrode composite binder, including sodium carboxymethyl cellulose, polyacrylic acid and styrene-butadiene rubber. Wherein the mass ratio of sodium carboxymethyl cellulose, polyacrylic acid and styrene-butadiene rubber is 2:2:3.

[0041] A method for preparing a negative electrode sheet containing a high specific capacity silicon-based negative electrode composite binder, comprising the following steps:

[0042] 1) Add 2.85 parts of sodium carboxymethylcellulose powder to deionized water and stir at a speed of 2800rpm. After stirring evenly, add 2.85 parts of polyacrylic acid to make the solid content of the liquid 5wt%, and stir for 30 minutes at a speed of 800rpm. Defoaming to obtain glue.

[0043] 2) Add 4 parts of Super P conductive agent to the above glue solution and stir for 2 hours at a speed of 2800pm to prepare a conductive solution.

[0044]3) Add 50 parts of SiO negative electrode powder to the above conduc...

Embodiment 3

[0051] A high specific capacity silicon-based negative electrode composite binder, comprising 5wt% sodium carboxymethylcellulose, 30wt% polyacrylic acid and 65wt% styrene-butadiene rubber.

[0052] A method for preparing a negative electrode sheet containing a high specific capacity silicon-based negative electrode composite binder, comprising the following steps:

[0053] 1) Add 0.5 parts of sodium carboxymethylcellulose powder to deionized water and stir at a speed of 2000rpm. After stirring evenly, add 3 parts of polyacrylic acid to make the solid content of the liquid 5wt%, and stir for 35 minutes at a speed of 400rpm. Defoaming to obtain glue.

[0054] 2) Add 1 part of Super P conductive agent to the above glue solution and stir at 2000rpm for 2.5h to prepare a conductive solution.

[0055] 3) Add 92 parts of SiO negative electrode powder to the above conductive liquid, stir at 400rpm for 12min, then stir at 2000rpm for 70min, then add 1 part of natural graphite, stir at...

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Abstract

The invention discloses a high-specific-capacity silicon-based negative electrode composite binder and a preparation method for a negative plate containing the same, belonging to the field of binders for batteries. The high-specific-capacity silicon-based negative electrode composite binder comprises 5 to 50 wt% of carboxymethylcellulose sodium, 5 to 30 wt% of polyacrylic acid and 20 to 90 wt% of styrene-butadiene rubber. The preparation method for the negative plate comprises the following steps: binder preparation; addition of a conductive agent; addition of a main material; sieving; coating; high temperature polymerization; rolling; and punching. The composite binder provided by the invention can overcome the technical problem of short cycle life of a battery caused by immense volume changes of a conventional silicon-based negative electrode material during intercalation and deintercalation of lithium ions.

Description

technical field [0001] The invention relates to the field of battery binders, in particular to a high specific capacity silicon-based negative electrode composite binder and a method for preparing a negative electrode sheet containing the binder. Background technique [0002] The theoretical capacity of silicon intercalated lithium is as high as 4200mAh / g, which is more than 10 times that of the current commercial negative electrode graphite material (theoretical capacity is 372mAh / g), and has important application prospects. However, after several charge-discharge cycles, the volume expansion rate of silicon materials is as high as 300% (much higher than that of graphite by 10%). The huge volume effect causes the pulverization of the silicon material, and the active material falls off from the current collector, resulting in very poor cycle stability of the battery, which is a hot issue that is of great concern to the international academic and industrial circles. [0003]...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/1395H01M10/0525
CPCH01M4/1395H01M4/622H01M10/0525Y02E60/10
Inventor 石先兴王慧敏严红吕豪杰
Owner WANXIANG 123 CO LTD
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