A composite conductive paste for positive and negative electrodes of a lithium ion battery and a preparation method thereof

Abstract

The invention is applicable to the technical field of lithium ion batteries and provides a composite conductive paste for positive and negative electrodes of a lithium ion battery and a preparation method thereof. The composite conductive paste for the positive and negative electrodes of the lithium ion battery comprises the following components in parts by weight: 5.0 to 7.5 parts of carbon nanotubes, 0.3 to 0.6 parts of a dispersing agent and 90 to 95 parts of N-Methyl pyrrolidone; the carbon nanotubes are composed of large-diameter carbon nanotubes and small-diameter carbon nanotubes, wherein the diameter of each large-diameter carbon nanotube is 30 to 150 nm, and the diameter of each small-diameter carbon nanotube is 1 to 30 nm, and the diameter difference between the large-diameter carbon nanotube and the small-diameter carbon nanotube is 15 nm or more; and the weight ratio of the large-diameter carbon nanotubes to the small-diameter carbon nanotubes is (3-7) :( 7-3). The composite conductive paste for the positive and negative electrodes of the lithium ion battery provided by the invention can form a good conductive network with the active materials, and thus the internal resistance of the lithium ion battery is reduced, and the lithium ion battery can have electrochemical properties such as excellent cycle life and energy density.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a composite conductive paste for positive and negative electrodes of lithium ion batteries and a preparation method thereof. Background technique [0002] In the preparation process of lithium-ion secondary batteries and capacitors, it is often necessary to add a certain amount of conductive agent to the positive and negative electrode ingredients. The conductive agent can effectively contact with the positive and negative active materials to form a good conductive network, thereby improving the rate performance of the battery. However, adding too much conductive agent will inevitably reduce the content of electrode active materials and reduce the capacity and energy density of the battery. For high-performance electronic devices, it is particularly important to choose a suitable conductive agent. [0003] Carbon nanotubes are emerging conductive agent...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a conductive paste for positive and negative electrodes of lithium-ion batteries, aiming at solving the problem of existing conductive paste products made of conductive carbon black or carbon nanotubes, or composited with conductive carbon black and carbon nanotubes, Lead to the problem that the main electrochemical performance of the battery, such as cycle life and energy density, has little room for improvement

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