Preparation method of high-capacity monocrystalline type ternary cathode material

Abstract

A preparation method of a high-capacity monocrystalline type ternary cathode material comprises steps as follows: S1, a nickel cobalt manganese hydroxide precursor of a core-shell structure is prepared with a coprecipitation method, a loose and porous core is prepared by intermittently introducing a certain quantity of bicarbonate at the initial stage of core making, after core making ends, and loose flaky shells are prepared by substantially reducing the rotation speed and increasing pH; meanwhile, at the core-shell transition stage, a dispersant is added to effectively prevent agglomerationof the shells due to decrease of the rotation speed; S2, the prepared precursor and lithium salt are mixed and calcined once in the oxygen-rich atmosphere at the high temperature, and the monocrystalline type ternary cathode material is obtained. A battery is prepared from the ternary cathode material and has high capacity and good safety performance due to high lithium ion transport efficiency and reduced anisotropy in crystals. The problem of poor capacity of the material because of low lithium ion transport efficiency of monocrystalline type ternary materials is effectively solved. Besides,the monocrystalline type ternary cathode material is prepared through one-time sintering, the preparation procedure 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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