Composite ternary positive electrode material, preparation method thereof and lithium-ion battery

Abstract

The invention relates to a composite ternary positive electrode material, a preparation method thereof and a lithium-ion battery. The preparation method of the composite ternary positive electrode material comprises the following steps: 1) uniformly mixing a precursor and a lithium source, and carrying out heat preservation at 500-900 DEG C for 5-20 hours to obtain a pre-sintered product; 2) uniformly mixing the pre-sintered product with an auxiliary agent, and carrying out heat preservation at 700-1000 DEG C for 5-20 hours to obtain a ternary material; and 3) carrying out oxide coating treatment on the ternary material prepared in the step 2) to obtain the composite ternary positive electrode material. According to the preparation method of the composite ternary positive electrode material provided by the invention, the ternary material with a layered structure is formed through low-temperature pre-sintering, so that a lithium source is fixed, and the problem of serious lithium loss caused by high-temperature sintering is reduced; then an auxiliary agent is added for sintering, so that the effects of reducing the sintering temperature and remodeling a crystal are achieved, and theternary material with high voltage and single crystal morphology is prepared; and finally, through oxide coating treatment, the interface stability of the material under high voltage is improved.

Description

technical field [0001] The invention belongs to the field of ternary positive electrode materials, and in particular relates to a composite ternary positive electrode material, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, low self-discharge, high open circuit voltage, high specific energy, long cycle life, no memory effect, and low environmental pollution. They are widely used in 3C, electric vehicle power supply, energy storage power supply and other fields. The core link in the lithium-ion battery industry chain is the manufacture of battery materials, and the performance of lithium-ion batteries largely depends on the performance of the cathode material. As the market demands higher and higher energy density, ternary materials have become one of the hot spots in the research of cathode materials. [0003] There are currently two ways to increase the gram capacity of ternar...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a preparation method of a composite ternary positive electrode material to solve the problem that the discharge platform voltage of the existing ternary positive electrode material is low

[0006] The second object of the present invention is to provide the composite ternary positive electrode material prepared by the above preparation method to solve the problem of low discharge platform voltage of the existing ternary positive electrode material

[0007] The third object of the present invention is to provide a lithium-ion battery using the above-mentioned composite ternary positive electrode material to solve the problem of low discharge platform voltage of the existing lithium-ion battery

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