Binder for lithium ion battery silicon-based anode and preparation method and application of the binder

Abstract

The invention discloses a binder for a lithium ion battery silicon-based anode and a preparation method and application of the binder, and belongs to the technical field of energy materials. The binder is prepared from the compositions in percentage by mass: 10-80% of chain macromolecules, 10-60% of conductive macromolecules and 10-60% of self-repairing macromolecules. According to the provided composite binder, through crosslinking modification of the chain macromolecules, the conductive macromolecules and the self-repairing macromolecules, a three-dimensional network structure composed of rigid and flexible coupling chains and bonds is obtained, electrical conductivity and self-repairability are achieved while good adhesivity and mechanical performance are achieved, and the adhesivity between an electrode material and a current collector can be increased by applying the binder to a lithium ion battery silicon-based anode material; the large volume change of the material in the charging and discharging cycle process is accommodated, and silicon particles can still maintain electrical conductivity after multiple cycles and pulverization and cracks generated after the cycles are self-repaired, so that electrical conductivity and stability of the whole electrode structure is improved.

Description

technical field [0001] The invention relates to the technical field of energy materials, in particular to a binder for a silicon-based negative electrode of a lithium-ion battery, a preparation method thereof, and an application in the preparation of a silicon negative electrode. Background technique [0002] As people's requirements for the performance of lithium-ion batteries are increasing day by day, traditional lithium-ion batteries with graphite (372mAh / g) as the negative electrode cannot meet people's needs, and the development of lithium-ion batteries with high-capacity silicon (4200mAh / g) as the negative electrode has become a scientific research goals of the world and industry. However, silicon exhibits a huge volume change (greater than 300%) due to the intercalation and extraction of lithium ions during charge and discharge, which leads to the pulverization of the electrode active material and detachment from the current collector, which in turn causes the electr...

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Problems solved by technology

[0010] The purpose of the present invention is to provide a multifunctional polymer composite binder with multiple network structures and both electrical conductivity and self-healing properties, aiming at solving the problems of poor electrical conductivity, large volume expansion, and easy dusting of silicon-based negative electrodes in lithium-ion batteries. delamination, which leads to the problem of rapid capacity fading

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