Lithium ion battery positive electrode slurry as well as preparation method and application thereof

Abstract

The invention discloses a lithium ion battery positive electrode slurry as well as a preparation method and application thereof. The preparation method comprises the following steps of (1) mixing a positive active material, a binder, a first conductive agent and a solvent to obtain the mixed slurry; and (2) mixing the mixed slurry with a second conductive agent so as to obtain the lithium ion battery positive electrode slurry, wherein the first conductive agent is composed of carbon nanotubes, graphene, conductive carbon black, a dispersing agent and the solvent, and the second conductive agent is conductive carbon black. By adopting the method, the distribution of the conductive agent in a positive plate can be remarkably improved, and the problem of poor electronic conductivity and ion transmission of the positive plate is solved, so that the positive plate can exert higher gram volume, and has better rate capability, low-temperature performance and cycle performance.

Description

technical field [0001] The invention belongs to the field of lithium batteries, and in particular relates to a positive electrode slurry of a lithium ion battery and a preparation method and application thereof. Background technique [0002] At present, the ternary cathode material LiNi x co y mn (1-x-y) o 2 Due to the characteristics of high gram capacity, high compacted density, and high voltage, it is more and more widely used in lithium-ion batteries, especially in the field of power batteries. Among them, single crystal ternary materials have better structural stability, especially Under high voltage conditions, it is also favored by power batteries. However, due to the large individual particles of single crystal materials, the electronic conductance and ion transport are poor. Contents of the invention [0003] The present invention mainly proposes based on the following problems: [0004] At present, the solution to the problem of poor electronic conductivity...

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Problems solved by technology

[0004] At present, the solution to the problem of poor electronic conductivity and ion transport of single crystal materials is mainly carried out from two aspects: material coating and positive electrode conductive agent optimization, but material coating will increase the cost of ternary materials, and the optimization of conductive agent is mainly composite conductive agent , but the existing positive plate prepared by composite conductive agent can not solve the problem of single crystal ternary material, such as pre-mixing binder solution and carbon nanotubes and then adding conductive agent SP (conductive carbon black), KS6 ( Conductive graphite), after uniform mixing, add the positive electrode active material to obtain the positive electrode slurry, and then use the positive electrode slurry to coat and dry the positive electrode sheet, however, due to the conductive agent particle size / pipe diameter / sheet used in the ternary positive electrode system The diameter is usually small and the specific surface area is large. It is difficult to disperse the conductive agent uniformly in the slurry when making the positive electrode sheet by this method, and it is difficult to form a good distribution on the surface of the positive electrode, which seriously affects the electrochemical performance of the single crystal ternary positive electrode.

[0005] In view of this, the present invention aims to propose a lithium-ion battery positive electrode slurry and its preparation method and application to improve the distribution of the conductive agent in the positive electrode sheet and solve the problems of poor electronic conductivity and ion transport of the positive electrode sheet

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