Binder and preparation method and application thereof

Abstract

The invention provides a binder and a preparation method and application thereof. The binder is prepared from the following components in percentage by mass: 60 to 70 weight percent of polyacrylonitrile, 15 to 25 weight percent of polyacrylic acid and 5 to 15 weight percent of polyacrylate; the preparation method of the binder comprises the following step: uniformly mixing polyacrylonitrile, polyacrylic acid and polyacrylate to obtain the binder. The binder provided by the invention can be used in a lithium ion battery negative electrode material, and under the condition of low content, the effect of inhibiting expansion of a negative electrode can be realized, and the capacity retention ratio of the negative electrode after long-time charge-discharge cycle is improved.

Description

technical field [0001] The invention belongs to the technical field of negative electrodes of lithium ion batteries, and in particular relates to a binder, a preparation method and application thereof. Background technique [0002] The use of lithium-ion batteries as electric vehicles or related energy storage devices requires batteries to have a long service life and safety performance. However, in the actual use of lithium-ion batteries, due to long-term repeated charging and discharging, the SEI film will gradually thicken, and the volume of the negative electrode will expand, especially for silicon materials. It will cause the pulverization and fragmentation of the material itself, and at the same time, it will cause damage to the electrode and produce cracks, etc., which will have a huge impact on the cycle life of the battery itself, and will cause expansion of the module, affecting the safety performance of the module. Therefore, the volume expansion of negative elec...

AI Technical Summary

Problems solved by technology

However, for the negative electrode binder system CMC+SBR, too high a proportion of CMC will not only cause the electrode sheet to be too brittle, but also increase the internal resistance of the battery. In addition, the low temperature performance of the negative electrode binder system CMC+SBR battery is generally poor.

[0005] However, lithium-ion battery anode materials are easy to swell during actual use, especially silicon anode materials, although they have the advantages of high capacity and low cost, their easy-to-swell characteristics seriously hinder their industrial application

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