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Lithium ion battery and negative electrode thereof

A lithium-ion battery and negative electrode technology, which is applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of poor battery rate performance, difficulty in lithium ion de-intercalation, and poor binder adhesion. , to achieve the effect of reducing expansion rate, good electrolyte resistance and enhancing bonding force

Inactive Publication Date: 2012-08-01
NINGDE AMPEREX TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, styrene-butadiene rubber (SBR) is generally used as a binder for water-based negative electrodes of lithium-ion batteries. The bonding force of the agent will be further weakened. When the thickness of the pole piece increases, the adhesion of the pole piece will be significantly weakened, and the thick pole piece will easily cause difficulty in lithium ion deintercalation, increase in polarization, and make lithium-ion batteries decompose at room temperature and low temperature. Lithium, poor battery rate performance and other issues

Method used

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  • Lithium ion battery and negative electrode thereof
  • Lithium ion battery and negative electrode thereof
  • Lithium ion battery and negative electrode thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Preparation of negative electrode:

[0034] The negative electrode slurry formula is based on the weight percentage of the dry material. It consists of three parts: 3% sodium alginate, 1.5% conductive carbon black, and 95.5% negative active material. The negative active material is artificial graphite, and the G / M of sodium alginate is 1.3. Its number-average molecular weight is about 500,000, its mass concentration is 1% aqueous solution at 25 ° C, the viscosity is 150mPa.s, the elastic modulus of sodium alginate is 3GPa, and the content of calcium impurities is 0.2%. During the preparation of the slurry, the solvent is water, and water accounts for 60% of the total slurry.

[0035] First, add water and sodium alginate into the stirring grinder according to the above formula, dissolve completely in a vacuum state to obtain a water-based polymer solution, then add conductive carbon black into the dissolved water-based polymer solution according to the formula, and stir ...

Embodiment 2

[0047] The difference from Example 1 is:

[0048] The formula of the negative electrode slurry is composed of 0.5% sodium alginate, 1.5% conductive carbon black, and 98% negative electrode active material in terms of dry material weight percentage. The negative electrode active material is natural graphite, and the G / M of sodium alginate is 1.1. Its number-average molecular weight is about 100,000, its mass concentration is 1%, the viscosity of the aqueous solution at 25°C is 1200mPa.s, the elastic modulus of sodium alginate is 4GPa, and the content of calcium impurities is 0.1%. During the preparation of the slurry, the solvent is water, and water accounts for 60% of the total slurry.

[0049] The rest are the same as in Embodiment 1, and will not be repeated here.

Embodiment 3

[0051] The difference from Example 1 is:

[0052] The formula of the negative electrode slurry is composed of 10% sodium alginate, 1.5% conductive carbon black, and 87.5% negative electrode active material in terms of dry material weight percentage. The negative electrode active material is natural graphite, and the G / M of sodium alginate is 1.0. Its number-average molecular weight is about 50,000, its mass concentration is 1%, the viscosity of the aqueous solution at 25°C is 50mPa.s, the elastic modulus of sodium alginate is 6GPa, and the content of calcium impurities is 0.15%. During the preparation of the slurry, the solvent is water, and water accounts for 60% of the total slurry.

[0053] The rest are the same as in Embodiment 1, and will not be repeated here.

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Abstract

The invention belongs to the technical field of a lithium ion battery and particularly relates to a negative electrode of the lithium ion battery. The negative electrode comprises a negative electrode current collector and a negative electrode active substance layer coated on the negative electrode current collector; the negative electrode active substance layer comprises a negative electrode active substance, a conductive agent and a binder; and the binder is alginate, wherein the alginate contains two stereoisomers, i.e. L-guluronic acid (G segment) and D-mannuronic acid (M segment), the ratio of G / M is less than or equal to 1.5, and the content of calcium impurities contained in the alginate is less than or equal to 0.3%. Compared with the prior art, the negative electrode has the advantages that after the alginate is adopted as the binder of the negative electrode of the lithium ion battery, the volume change of the lithium ion battery during the process of lithium de-intercalation can be inhibited, and the binding effect between the negative electrode active substance layer and the binder of the negative electrode is improved, so that the volume expansion coefficient of the battery during the cyclic process is lowered, and the properties of low temperature and multiplying factor of the lithium ion battery are improved. Moreover, the invention further discloses the lithium ion battery containing the negative electrode.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, more specifically, the invention relates to a lithium-ion battery negative electrode capable of effectively inhibiting graphite cycle expansion, so as to improve the low-temperature and rate performance of the lithium-ion battery, and a lithium-ion battery comprising the negative electrode . Background technique [0002] Since its commercialization, lithium-ion batteries have been widely used as power sources for various mobile devices due to their high energy density, high operating voltage, no memory effect, long cycle life, and no pollution to the environment, which makes them enter the large The practical phase of the scale. [0003] With the continuous multi-functionalization and refinement of various portable electronic devices, the energy density of lithium-ion batteries is also required to be higher and higher. In order to achieve the purpose of improving the energy densit...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/62H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 邓耀明柳娜许瑞谭欣欣赖旭伦王正
Owner NINGDE AMPEREX TECH
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