Preparation method of binder for dry electrode for lithium ion battery, and binder

Abstract

The invention relates to a preparation method of a binder for a dry electrode of a lithium ion battery, and the binder. The preparation method comprises the following steps: dissolving a vinyl fluoride monomer, an acrylic acid monomer or a sulfonic perfluorovinyl ether monomer into an organic solvent to form a mixed solution, and stirring for full reaction in a nitrogen protection atmosphere; precipitating the prepared copolymer with excessive methanol, filtering, thoroughly cleaning with distilled water, and removing the residual solvent, monomer and homopolymer; and completely drying to obtain the vinyl fluoride-acrylic acid-sulfovinylfluoride block copolymer. According to the method, acrylic acid molecules are embedded into a molecular chain to realize chemical bond combination with thesilicon negative electrode, so the bonding force between the binder and the electrode is effectively enhanced; and sulfonic perfluorovinyl ether is added, a good conductive network can be formed between the sulfonic perfluorovinyl ether and an active substance by utilizing the conductivity of a polymer of the sulfonic perfluorovinyl ether, and the electron and ion conductivity of the electrode isfurther improved, so that the comprehensive performance of the binder is improved.

Description

technical field [0001] The invention belongs to the field of polymer materials, and in particular relates to a preparation method of a binder used for dry-process electrodes of lithium-ion batteries. Background technique [0002] With the global energy shortage and the improvement of environmental protection awareness, the development of new energy has become an important development direction at present. Lithium-ion batteries have become a hot spot in the energy industry due to their advantages such as high working voltage, no memory effect, small self-discharge and long cycle life. Widely used in popular industries such as portable electronic equipment, electric vehicles and hybrid electric vehicles. In the research of anode materials for lithium-ion batteries, silicon materials have attracted great attention due to their extremely high theoretical specific capacity, extremely low electrochemical potential during lithiation / delithiation, high safety and environmental frien...

AI Technical Summary

Problems solved by technology

The traditional commercial binder polyvinylidene fluoride (PVDF) can no longer meet the requirements of developing high specific capacity electrodes due to its shortcomings such as high cost and poor adhesion to active materials.

Although the low-cost and environmentally friendly sodium carboxymethylcellulose (CMC) can significantly improve the bonding performance and the initial Coulombic efficiency of the electrode, the binder has poor flexibility and cannot withstand the volume expansion of active materials with high specific capacity.