Three-dimensional network water-based composite binder and application thereof in lithium ion battery

A lithium-ion battery and three-dimensional network technology, which is applied in the field of new energy and new materials, can solve the problems of insufficient cycle stability of lithium-ion batteries, and achieve the effects of ensuring rate performance, alleviating damage, and simple operation

Active Publication Date: 2020-05-19
SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to develop a new type of water-soluble binder for the problem of insufficient cycle stability of existing lithium-ion batteries containing water-soluble binders agent, while maintaining good adhesion to the active material, it can improve the cycle stability of the lithium-ion battery. Another object of the present invention is to develop an environmentally friendly lithium-ion battery with improved cycle stability.

Method used

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  • Three-dimensional network water-based composite binder and application thereof in lithium ion battery
  • Three-dimensional network water-based composite binder and application thereof in lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] In a 1L reactor, add 1g of polyvinyl alcohol into 200mL of deionized water, raise the temperature to 80°C, and cool down to room temperature after the polyvinyl alcohol is completely dissolved. Add 2.5g nonylphenol polyoxyethylene ether, 90g vinyl acetate and 5g acrylic acid, add sodium bicarbonate solution to adjust the pH to 6-7, stir at high speed to emulsify. After vacuuming, nitrogen gas was introduced for 30 minutes, then 1.5 g of potassium persulfate was added, and the temperature was raised to 70° C. for 6 hours to prepare an aqueous polymer emulsion.

[0033]Take 20 g of the prepared water-based polymer emulsion and mix with 75 g of sodium alginate solution, then add 5 g of calcium acetate solution, and mix evenly to prepare a three-dimensional network water-based composite binder.

[0034] Mix SiC450, conductive agent Super P, and the prepared three-dimensional network water-based composite binder at a mass ratio of 95:1:4, and use an appropriate amount of dei...

Embodiment 2

[0036] In a 1L reactor, add 1g of polyvinyl alcohol into 200mL of deionized water, raise the temperature to 80°C, and cool down to room temperature after the polyvinyl alcohol is completely dissolved. Add 5g of sodium lauryl sulfate, 80g of vinyl acetate, add sodium bicarbonate solution to adjust the pH to 6-7, stir at high speed for emulsification. After evacuating, nitrogen gas was introduced for 30 minutes, and then ethylene was introduced into the reactor so that the amount of ethylene added was 12.5 g. After the ethylene pressure reached a constant value, 1.5 g of azobisisobutylamidine was added, and the temperature was raised to 100° C. for 5 h.

[0037] Take 30g of the prepared water-based polymer emulsion and mix with 60g of polyacrylic acid solution, then add 10g of γ-aminopropyl triethoxysilane solution, and mix evenly to prepare a three-dimensional network water-based composite binder.

[0038] Mix SiC450, conductive agent Super P, and the prepared three-dimensional...

Embodiment 3

[0040] In a 1L reactor, add 1g of polyvinyl alcohol into 200mL of deionized water, raise the temperature to 80°C, and cool down to room temperature after the polyvinyl alcohol is completely dissolved. Add 35g of vinyl acetate, 15g of acrylate, and dropwise add 5% lithium hydroxide solution to adjust the pH to neutral. After vacuuming, nitrogen gas is introduced for 30 minutes, 0.8g of potassium persulfate is added, and the temperature is raised to 70°C for 2 hours. Then add a mixed solution of 35g vinyl acetate, 12.5g acrylate and 0.5g potassium persulfate drop by drop, strictly control the dropping speed, make the mixed solution drop for 2h, and continue to react for 3h. Finally, continue to add 0.2 g of potassium persulfate solution to react for 2 h, take it out, and add 5% lithium hydroxide solution to adjust the pH of the solution to neutral.

[0041] Take 40 g of the prepared water-based polymer emulsion and mix with 55 g of sodium alginate solution, then add 5 g of calci...

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PUM

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Abstract

The invention provides a three-dimensional network water-based composite binder, which is prepared from the following components in percentage by weight: 5 to 50 percent of water-based polymer emulsion, 94.5 to 50 percent of water-soluble polymer and 0.5 to 10 percent of cross-linking agent. The three-dimensional network water-based composite binder is prepared by crosslinking the water-based polymer emulsion and the water-soluble polymer by a crosslinking agent to form a three-dimensional network molecular structure, wherein the water-based polymer emulsion is a water-based polyurethane emulsion or a vinyl acetate water-based copolymer emulsion. The invention also provides a negative electrode prepared from the three-dimensional network water-based composite binder and a lithium ion battery containing the negative electrode. The water-soluble polymer has relatively strong bonding force on the negative electrode material; the water-based polymer emulsion endows the polymer binder witha certain elasticity, and the cross-linking agent endows the binder with a three-dimensional molecular network structure, so that the toughness of the binder is enhanced, the damage of the volume change of active substances to an electrode plate structure in the charging and discharging process of the battery can be buffered, and the cycling stability of the lithium ion battery is maintained.

Description

technical field [0001] The invention relates to the technical field of new energy and new materials, in particular to a three-dimensional network water-based composite binder, a lithium-ion battery negative electrode containing the three-dimensional network water-based composite binder, and a lithium-ion battery containing the lithium-ion battery negative electrode. Background technique [0002] Binder is one of the important auxiliary functional materials in lithium-ion batteries, and is the main source of the mechanical properties of the entire battery electrode, which has an important impact on the production process of the electrode and the electrochemical performance of the battery. Binders for lithium-ion batteries are polymer adhesives, which are divided into non-aqueous binders and water-based binders. The non-aqueous binder is mainly polyvinylidene fluoride (PVDF), and toxic organic solvents (such as N-methylpyrrolidone) need to be used in the slurry preparation pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M10/0525
CPCH01M4/622H01M10/0525H01M2004/027Y02E60/10
Inventor 邓永红郑培涛易欢向书槐王朝阳
Owner SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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