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Negative electrode, preparation method thereof, and lithium ion battery using negative electrode

A negative electrode and deionized water technology, applied in electrode manufacturing, battery electrodes, secondary batteries, etc., can solve problems such as low viscosity, poor electrode performance, and poor electrode processing performance

Inactive Publication Date: 2020-12-11
ENVISION DYNAMICS TECH (JIANGSU) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the plasma made of the existing carboxymethyl cellulose salt has low ion conductivity, resulting in poor electrode performance, or low viscosity, resulting in poor electrode processing performance

Method used

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  • Negative electrode, preparation method thereof, and lithium ion battery using negative electrode
  • Negative electrode, preparation method thereof, and lithium ion battery using negative electrode

Examples

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preparation example Construction

[0064] The method for preparing the negative electrode according to the first aspect of the present invention provided as the second aspect of the present invention comprises the steps of

[0065] a. Homogenizing: mixing and stirring the binder, the conductive agent, the negative electrode active material, and the electrode thickener to form a slurry;

[0066] b. Coating: the slurry is diluted with deionized water, coated on the current collector, and then compacted to form the negative electrode.

[0067] In one embodiment, the above coating is double-sided coating.

[0068] In one embodiment, the above-mentioned coating is carried out by a coating machine, and the coating speed ranges from 0.8 to 1.2 m / min -1 .

[0069] In one embodiment, the above-mentioned compaction is carried out by a roller press, and the compacted density ranges from 1.4 to 1.8 g / cm -3 , The rolling speed range is 0.6~1.0m / min.

[0070] In one embodiment, the above-mentioned binder is styrene-butad...

preparation example

[0077] [Preparation Example] Preparation of Electrode Thickener

[0078] Preparation of carboxymethylcellulose lithium (DS=1.2):

[0079] Method 1: Take cellulose raw materials (refined cotton, wood pulp, etc.) with an average degree of substitution of 1.2, add sodium hydroxide to alkalize, add monochloroacetic acid to react, and then add acetic acid solution, in a mixed solution of ethanol and water at 35°C After reacting for 2 hours, filter and wash repeatedly with the mixed solvent to obtain purified carboxymethyl cellulose, place the prepared carboxymethyl cellulose in a mixed solution of ethanol and water, and react with 7wt% LiOH at 50°C for 2 hours , adding acetic acid to adjust the pH value to x can obtain lithium carboxymethyl cellulose with an average substitution degree of 1.2.

[0080] Method 2: Take cellulose raw materials (refined cotton, wood pulp, etc.) with an average degree of substitution of 1.2, disperse them in a mixed solution of isopropanol and distille...

Embodiment 6

[0094] a. Homogenization: Disperse and mix 571 parts of electrode thickener and 8 parts of conductive agent prepared in Example 1 to form 579 parts of conductive glue, mix 579 parts of conductive glue with 966 parts of graphite and stir for 60 minutes (revolution 20rpm, rotation 800rpm) Form a slurry, then add 300 parts of deionized water to reduce the solid content to about 53%, continue to stir for 90min (revolution 35rpm, rotation 2500rpm, vacuum -90kPa), and finally add 45 parts of SBR emulsion and stir for 30min (revolution 20rpm, rotation 800rpm , vacuum degree-90kPa), complete the homogenization process.

[0095] b. Coating: The slurry is coated on the copper foil by a coating machine. The foil is coated on both sides. The coating surface density is controlled at about 10mg cm-2, and the coating speed is 1m / min-1. The temperature of the oven is maintained at around 65°C and 80°C.

[0096] c. Compaction: use a roller press, adjust the parameters of the roller press, so ...

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Abstract

The invention discloses a negative electrode, a preparation method thereof and a lithium ion battery using the negative electrode. In the application, the negative electrode comprises a current collector and a negative electrode active material layer on the current collector, and the negative electrode active material layer comprises a binder; a conductive agent; a negative electrode active material; and an electrode thickening agent, wherein the electrode thickening agent comprises deionized water; a first polymer, and a second polymer; wherein both the first polymer and the second polymer are cellulose ethers or salts thereof, and the average degree of substitution of the first polymer is greater than the average degree of substitution of the second polymer, so that the electrode processability can be maintained or improved while the ion conductivity is improved.

Description

technical field [0001] The embodiments of the present invention relate to the field of lithium ion batteries, in particular to negative electrodes, their preparation methods and lithium ion batteries using the same. Background technique [0002] The electrodes of lithium batteries are mainly composed of active materials, conductive agents, binders and current collectors. Binders are divided into oily binders and water-based binders. The commonly used water-based binder is styrene-butadiene rubber, but the use of styrene-butadiene rubber alone can easily cause the pole piece to swell and affect the electrochemical performance of the battery. [0003] The inventor finds that there are at least the following problems in the prior art: [0004] Usually, carboxymethyl cellulose salt and styrene-butadiene rubber are used together to relieve the swelling of the pole piece. However, the existing plasma made of carboxymethyl cellulose salt has low ion-conducting ability, resulting ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/62H01M4/131H01M4/133H01M4/134H01M4/136H01M4/1391H01M4/1393H01M4/1395H01M4/1397H01M4/04H01M10/0525
CPCH01M4/0404H01M4/0435H01M4/131H01M4/133H01M4/134H01M4/136H01M4/1391H01M4/1393H01M4/1395H01M4/1397H01M4/362H01M4/62H01M10/0525Y02E60/10
Inventor 魏迪锋李昊孙化雨
Owner ENVISION DYNAMICS TECH (JIANGSU) CO LTD
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