A method for improving cycle performance of silicon-based negative electrode

Abstract

The invention discloses a method for improving cycling performance of a silicon-based anode. The method comprises the following steps: evenly mixing a silicon-based material with a conductive agent, a thickening agent and an acrylic resin binder, coating and drying to obtain an anode pole piece; and performing Gamma ray irradiation on the anode pole piece in nitrogen atmosphere and obtaining the silicon-based anode. The method for improving the cycling performance of the silicon-based anode provided by the invention can not only improve the long cycling performance of the silicon-based anode, has a certain promotion to the initial coulombic efficiency of the silicon-based material, and has the advantages of being simple in process, strong in applicability (PAA class all can), suitable for mass production, and is expected to have a good practical application in the field of lithium ion batteries.

Description

technical field [0001] The invention relates to the technical field of new energy lithium ion batteries, in particular to a method for improving the cycle performance of a silicon-based negative electrode. Background technique [0002] In recent years, in order to develop rechargeable lithium-ion batteries with high energy density, a lot of work has focused on silicon-based anode materials because silicon has an ultra-high theoretical capacity (4200mAh / g), but due to the The large volume effect leads to the pulverization of silicon particles, the loss of electrical contact with the conductive agent, and the destruction of the entire electrode structure, resulting in capacity attenuation and poor cycle performance. And a very important way to solve these problems is to find a suitable binder, the common ones are PAA, CMC / SBR, sodium alginate, chitosan, PI, PAI, etc., but most of them are point contact or line In contact, the adhesive force is not strong enough to withstand t...

AI Technical Summary

Problems solved by technology

[0002] In recent years, in order to develop rechargeable lithium-ion batteries with high energy density, a lot of work has focused on silicon-based anode materials because silicon has an ultra-high theoretical capacity (4200mAh / g), but due to the Accompanied by a large volume effect, the pulverization of silicon particles and the loss of electrical contact with the conductive agent destroy the entire electrode structure, resulting in capacity attenuation and poor cycle performance

And a very important way to solve these problems is to find a suitable binder, the common ones are PAA, CMC / SBR, sodium alginate, chitosan, PI, PAI, etc., but most of them are point contact or line Contact, adhesion is not strong enough to withstand up to 300% volume change of silicon, so a 3D structured adhesive is required

However, most of the existing technologies adopt the method of adding a crosslinking agent and heat-treating the pole piece to obtain the required 3D structure, but this method increases the processing cost and is not conducive to industrial production.

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