Ternary positive electrode material of lithium ion battery and preparation method of ternary positive electrode material

Abstract

The invention discloses a ternary positive electrode material of a lithium ion battery and a preparation method of the ternary positive electrode material. The ternary positive electrode material comprises a ternary material and a coating layer coated on the surface of the ternary material, wherein the coating layer comprises a Li < 2 + x > C < 1-x > Bx O3 coating agent, and x is greater than 0 and less than 1. The preparation method comprises the steps of (1) mixing a ternary positive electrode material precursor with a lithium source and a doping agent, and carrying out primary calcination to obtain primary calcined sample powder; (2) dispersing the primary calcined sample powder into an alkaline solution, stirring to fully wet the primary calcined sample powder, performing suction filtration, drying in a vacuum environment, and performing secondary calcination to obtain secondary calcined sample powder; and (3) uniformly mixing the secondary calcined sample powder with a coating material comprising a Li < 2 + x > C < 1-x > Bx O3 coating agent, and performing tertiary calcination. By improving the coating agent and the preparation method, the surface of the ternary positive electrode material is coated with a layer of material with relatively high lithium ion conductivity, so that the capacity performance and the cycle performance of the battery are effectively improved.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium ion batteries, in particular to a ternary positive electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] With the development of new energy vehicles, lithium-ion power batteries have attracted much attention as the most popular electric vehicle power batteries. Compared with the mature and stable graphite anode, the research and development of cathode materials with high capacity, long life, low cost, safety and environmental protection is particularly urgent. The currently commonly used cathode materials for lithium batteries mainly include layered lithium cobaltate, ternary materials, spinel-structured lithium manganate and olivine-structured lithium iron phosphate. Ternary materials have high specific capacity, energy density and power density, and relatively stable performance, so they have become popular materials ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the problem that the introduction of B will reduce the lithium ion conductivity of the material when the boron-containing coating agent is used to coat and modify the ternary positive electrode material in the prior art, thus affecting the performance of the battery, and provides a lithium ion battery The ternary positive electrode material and its preparation method, by improving the coating agent and the preparation method, a layer of material with high lithium ion conductivity is coated on the surface of the ternary positive electrode material, and the capacity performance of the material is improved while reducing ions. Resistivity improves the rate performance; at the same time, the coating layer can effectively slow down the side reaction between the ternary material and the electrolyte, improve its cycle performance and prolong the battery life