Slurry mixing method for silicon-carbon negative electrode

Abstract

The invention discloses a slurry mixing method of a silicon-carbon negative electrode. The method comprises the following steps: dissolving a binder in water, and uniformly stirring to prepare a gluesolution A; adding a liquid conductive agent into the glue solution A, and uniformly stirring to prepare a glue solution B; and adding a negative electrode active substance, a solid conductive agent and a solvent into the glue solution B, continuously stirring, and carrying out viscosity adjustment to complete slurry mixing so as to obtain the silicon-carbon negative electrode slurry. According tothe invention, the binder and the liquid conductive agent are mixed, are uniformly dispersed and then are continuously mixed with other negative electrode raw materials, so that the damage to a slurry mixing cylinder and the pole climbing phenomenon in a dry slurry mixing process are avoided, and the problem of quite low solid content in common wet slurry mixing is also solved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a method for mixing silicon-carbon negative electrodes. Background technique [0002] With the improvement of people's requirements for energy density, the active materials of positive and negative electrodes of lithium-ion batteries are constantly updated, which makes new requirements for the combination of positive and negative electrodes. [0003] Silicon has a high theoretical specific capacity of up to 3572mAh / g energy density, but in the charge and discharge process, there is a large volume expansion (about 300%). SiO has attracted new attention due to its small volume expansion rate (150%) and high theoretical specific capacity of 1200mAh / g. In order to make the negative electrode obtain better cycle stability, ionic and electronic conductivity during use, the negative electrode is often used as a SiOx / C composite system. [0004] The steps of t...

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Problems solved by technology

[0004] The steps of the traditional dry mixing process are relatively complicated. The dry mixing process in the early stage will cause certain wear and tear on the mixing cylinder, and the viscosity of the powder is relatively high during the mixing process, which may easily lead to the rod climbing effect. The most important thing is the dry mixing process. The solid content of the slurry is low, and there are certain requirements for the process parameters of the slurry during the wetting process of the powder

However, the traditional wet slurry mixing process generally has the problem of low solid content of the slurry, which brings a lot of inconvenience to the industrial production of silicon carbon negative electrodes.

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