A kind of preparation method of high-capacity single crystal type ternary cathode material

Abstract

A method for preparing a high-capacity single crystal ternary positive electrode material, the steps are: 1. Prepare a nickel-cobalt-manganese hydroxide precursor with a core-shell structure by co-precipitation method, and inject quantitative bicarbonate intermittently in the early stage of nucleation To prepare a loose and porous core, after the nucleation is completed, a loose flaky shell is prepared by greatly reducing the rotational speed and increasing the pH. At the same time, in the core-shell transformation stage, adding a dispersant effectively prevents the reunion between the shells caused by the reduction of the rotational speed; 2. The prepared precursor is mixed with lithium salt and calcined at a high temperature in an oxygen-enriched atmosphere to obtain a single crystal ternary cathode material. The ternary cathode material of the present invention is prepared into a battery, which has high lithium ion transmission efficiency, reduced anisotropy inside the crystal, and the battery has high capacity and good safety performance. It effectively solves the problem of poor performance of material capacity caused by low lithium ion transmission efficiency of single crystal ternary materials. At the same time, the single crystal ternary cathode material is prepared by one-time sintering, the preparation process is simple, and the production cost is low.

Description

technical field [0001] The invention relates to the field of lithium-ion battery materials, in particular to a method for preparing a high-capacity single crystal ternary positive electrode material. Background technique [0002] The explosive development of new energy vehicles has driven the explosive growth of demand for lithium-ion batteries, and the lithium battery industry chain is facing major challenges and opportunities from top to bottom. [0003] As new energy vehicles have higher and higher requirements for cruising range, high-nickel and low-cobalt ternary cathode materials have gradually become one of the main directions for the development of lithium-ion battery cathode materials. At the same time, the high safety performance of new energy vehicles is an eternal pursuit, so the single crystallization of ternary cathode materials will also become another main development direction of cathode materials for lithium-ion batteries. [0004] At present, the ternary ...

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Problems solved by technology

[0004] At present, the ternary cathode material is mainly composed of secondary spherical particles formed by the agglomeration of primary nanoparticles. During the charging and discharging process of the battery, the volume of the lithium ion deintercalation positive electrode material will shrink and expand to a certain extent, and with the degree of charge and discharge As the number of cycles increases, the volume change of the material will also increase, which leads to the following problems: 1. Due to the existence of grain boundaries between the primary nanoparticles, cracks will appear between the grain boundaries during the charging and discharging process. Seriously affect the performance of the electrical properties of the material; 2. During the manufacturing process of the battery, the secondary spherical particles are easily crushed, which intensifies the interface reaction between the material and the electrolyte, resulting in a serious deterioration of the electrical properties and safety performance of the material

However, compared with secondary spherical particles, single crystal ternary materials are slightly lacking in capacity development, mainly because the lithium ion transmission distance of single crystal particles is greater than that of primary nanoparticles, and the nanometerization of single crystal particles will inevitably sacrifice the volume of the battery energy density, so how to improve the capacity of single crystal materials has very important research significance

At the same time, the traditional preparation process of single crystal materials requires higher sintering requirements, resulting in cumbersome production processes and high production costs, so it also needs to be solved

[0006] For example: the preparation of existing single crystal ternary materials is mainly realized by segmental sintering and adding additives, and the regulation of single crystal ternary materials by means of sintering not only has high energy consumption and low production capacity, but also cannot fundamentally improve single crystal ternary materials. Lithium ion transport properties of materials

The single crystal ternary positive electrode material prepared by patent CN104979546A has too high BET of flower cluster precursor particles, which is not conducive to filling during sintering, and the production capacity is low, and the method obtains the final Single crystal ternary cathode material, the sintering process is cumbersome and the production cost is high

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