Preparation method of high-nickel ternary cathode material

Abstract

The invention discloses a preparation method of a high-nickel ternary cathode material. The method comprises the steps of 1) pre-oxidizing a high-nickel ternary cathode material precursor with an oxidizing agent to obtain an oxidized high-nickel ternary precursor; 2) uniformly mixing the pre-oxidized high-nickel ternary precursor with a lithium source and a modified assistant, and performing calcining to obtain an oxidized and modified high-nickel ternary cathode material; 3) carrying out coating modification of a lithium-containing compound on the oxidized and modified high-nickel ternary cathode material to obtain a coated and modified high-nickel ternary cathode material for a power battery. According to the method disclosed by the invention, the material precursor is pre-oxidized withthe oxidizing agent, so that Ni<2+> can be fully oxidized into Ni<3+>, the cation mixing degree of the material is reduced, and the capacity of the material is expanded; and through the coating modification of the lithium-containing compound, the content of residual alkali on the surface of the material can be reduced, the generation of side reactions can be effectively inhibited, the embedding and separation of lithium ions are improved, and finally the cycling performance and the rate performance of the material are improved.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion batteries, and in particular relates to a preparation method of a high-nickel ternary positive electrode material. technical background [0002] Benefiting from the rapid development of the new energy vehicle market, the demand for power batteries continues to increase. With the high requirements of new energy vehicles for cruising range, there are also higher requirements for the energy density, cycle performance and safety performance of lithium-ion batteries. High-nickel-based ternary cathode materials, because of their low cost and high capacity, have become the focus of attention of cathode materials and have a very broad market in the field of power batteries. [0003] During the preparation of high-nickel cathode materials, Ni 2+ Difficult to be oxidized to Ni 3+ , due to Ni 2+ (0.069nm) and Li + (0.076nm) radius is very close, unoxidized Ni 2+ Easy access to...

AI Technical Summary

Problems solved by technology

For example, the invention patent with application number 201810174055.2 achieves the purpose of pre-oxidation modification by pre-sintering the precursor, but this method requires an additional calcination process, resulting in an increase in cost

[0004] An effective way to improve the electrochemical performance of high-nickel cathode materials is to modify the surface of the material, such as using magnesium oxide and aluminum oxide for surface coating. This method can inhibit the side reaction between the active material and the electrolyte to a certain extent. Improve the cycle performance of the material, but because the oxide coating layer is an ion insulating layer, it will hinder the insertion and extraction of lithium ions

For example, the invention patent with application number 201711042631.X uses alumina and boron oxide to coat and modify the material, but since alumina and boron oxide are electrochemically inert substances, it will hinder the capacity of the active material.

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