Lithium ion battery cathode material and preparation method thereof and lithium ion battery

Abstract

The purpose of the invention is to present a lithium ion battery cathode material and a preparation method thereof and a lithium ion battery. The cathode material includes a cathode active material, lithium phosphate arranged on at least part of the outer surface of the cathode active material, and a coating layer coating the exposed outer surfaces of the cathode active material and the lithium phosphate and including a conductive polymer. Thus, the residual alkali content on the surface of the cathode active material is low, and the rate performance stability and cyclic capacity retention rate of the cathode material can be improved. The lithium phosphate and the conductive polymer enable the cathode material to have ion-electron conductivity (double conduction), and further improve the rate performance stability and cyclic capacity retention rate of the cathode material. The coating layer can reduce or prevent the side reaction between the cathode active material and the electrolyteand improve the service life of the cathode material.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular, to a lithium ion battery cathode material, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in electric vehicles, hybrid vehicles and energy storage systems due to their high capacity and high energy density. As one of the core components of lithium-ion batteries, cathode materials have a significant impact on the performance of lithium-ion batteries. [0003] At present, researchers have found that high-nickel cathode materials are gradually replacing LiCoO2 cathode materials due to their advantages of high capacity and low price. However, high-nickel cathode materials have poor rate and cycle performance under high voltage. The residual alkali content on the surface of the positive electrode material. In addition, the positive electrode material in the battery is in contact with the electrol...

AI Technical Summary

Problems solved by technology

[0003] At present, researchers have found that high-nickel cathode materials are gradually replacing LiCoO2 cathode materials due to their advantages of high capacity and low price. However, high-nickel cathode materials have poor rate and cycle performance under high voltage. Residual alkali content on the surface of positive electrode material

In addition, the positive electrode material in the battery is in contact with the electrolyte, and the positive electrode material is easy to chemically react with the electrolyte, causing the transition metal in the positive electrode material to dissolve into the electrolyte, thereby increasing the interface impedance of the positive electrode material and reducing the capacity of the battery.

[0004] Therefore, research on cathode materials for lithium-ion batteries needs to be in-depth

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