Composite adhesive, pole piece prepared by means of the composite adhesive, preparation method and application thereof

Abstract

The invention relates to a composite adhesive, a pole piece prepared by means of the composite adhesive, a preparation method and an application thereof, wherein the composite adhesive, the pole piece, the preparation method and the application thereof belong to the technical field of energy storage devices. The composite adhesive is composed of the following components by weight: 1-13% of phosphoric acid, 20-45% of polyvinylidene fluoride, 5-9% of phenolic resin, 2-3% of amino resin, 6-11% of polyacrylate, 10-30% of acrylate terpolymer latex, 1-4% of carboxymethylcellulose sodium, 3-17% of polyimide, 2-4% of ethanol and 6-18% of N-methylpyrrolidone. The composite adhesive can reduce the internal resistance of a lithium ion battery or a super-capacitor and settle problems such as electrode powdering and electrode peeling-off caused by size increase of the pole piece. Utilization rate and cycle life of the electrode material are improved.

Description

technical field [0001] The invention relates to a composite binder, a pole piece prepared by using the composite binder, a preparation method and an application thereof, and belongs to the technical field of energy storage devices. Background technique [0002] The binder is a very important part of the electrode materials of lithium-ion batteries and supercapacitors. The main function of the binder is to bind and maintain the active material, enhance the contact between the electrode active material and the conductive agent, and the active material and the current collector. Electronic contact, to better stabilize the structure of the pole piece. Moreover, the binder can play a certain role in buffering the volume expansion / shrinkage of lithium-ion battery electrodes during charging and discharging. Generally speaking, the properties of binders, such as cohesive force, flexibility, alkali resistance, hydrophilicity, etc., directly affect the performance of lithium-ion batt...

AI Technical Summary

Problems solved by technology

In recent years, studies have found that for high-capacity electrode materials, especially silicon-based negative electrode materials, the volume expansion reaches more than 300% during the charging and discharging process, and the internal stress generated by the drastic volume change can easily lead to powdering and peeling of the electrode, resulting in battery failure. performance deteriorates dramatically

For porous and large surface area electrode materials, blindly increasing the content of the binder in the electrode material will increase the electrode sheet resistance, greatly reducing the energy density and comprehensive performance (such as power, Coulombic efficiency, cycle life, etc.)

Images