Three-dimensional mixed conductive adhesive used for lithium battery, and battery containing adhesive

Abstract

The invention provides a three-dimensional mixed conductive adhesive used for lithium battery, and a battery containing the adhesive. The adhesive contains a carbon nanotube, a graphene and a polymerhaving a chemical bonding effect with the carbon nanotube and the graphene. The carbon nanotube and the graphene in the adhesive are mixed according to a certain proportion to form a three-dimensionalconductive network; polymer groups and groups on the graphene carbon nanotube are effectively combined to improve the intensity of the compound; and the compound is perfectly dispersed when the electrode slurry is prepared. During the charging-discharging process, the three-dimensional compound conductive adhesive is capable of better controlling the expansion and the shrinkage of the active material of the electrode plate, and effectively improves the cycling stability and the rate capability of high-capacity high-volume-change type electrode material, such as the silicon-based cathode material, the tin-based cathode material, and the high-volume-change type electrode material that can be expanded into the new battery system in the future.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a three-dimensional mixed conductive adhesive for lithium batteries and a battery containing the adhesive. Background technique: [0002] Lithium-ion batteries have outstanding advantages such as high specific energy, small self-discharge, long service life, green and pollution-free, and have been widely used in portable electronic products and electric vehicles. With the development and progress of society, the further application of lithium-ion batteries urgently needs to increase the energy density, and the development of electrode materials with high specific capacity is one of the effective ways. Among the negative electrode materials, carbon materials are mainly commercialized at present, and their theoretical specific capacity is relatively low, about 372 mA h g-1. Silicon has attracted more and more attention because of its high theoretical specific capacity (about 357...

AI Technical Summary

Problems solved by technology

PVDF has poor adhesion and flexibility, and the effect of inhibiting the expansion of the pole piece is also very limited. It is difficult to improve the capacity and rate characteristics of the battery. In addition, the price of PVDF and its solvent is relatively high, which increases the cost of lithium-ion batteries.

SBR / CMC water-based binder is widely used in the market, but due to its own reasons, it is difficult to apply it to the preparation of positive electrode sheets. It has a relatively mature application in traditional graphite systems, but it is not suitable for high capacity, especially high volume change. The electrode material still shows poor effect of inhibiting expansion

On the other hand, in order to increase the energy density of the battery, the amount of conductive additives is also controlled within 5%, and it is difficult to realize the high capacity and high rate performance of the material.

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