Ternary positive electrode material and preparation method and application thereof

Abstract

The invention provides a ternary positive electrode material as well as a preparation method and application thereof. The ternary positive electrode material is of a three-dimensional hollow structure. According to the present invention, a precursor of a three-dimensional metal organic framework is prepared through a hydrothermal method, and then the ternary positive electrode material is obtainedthrough presintering, lithium doping, high-temperature calcining, mixing and low-temperature calcining. The porous structure of the ternary positive electrode material is beneficial to the storage and rapid transmission of lithium ions, and the rate capability and the cycle performance of the ternary positive electrode material are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery materials, and relates to a ternary positive electrode material and a preparation method and application thereof. Background technique [0002] With the rapid development of the new energy industry, ternary materials have become an important R&D and production plan for major new energy companies, and the electric vehicle market is paying more and more attention to battery safety. Although high-nickel ternary batteries of 8 series or above The energy density is higher, but there are greater security risks, and the market needs to slow down. From the perspective of positive electrode materials, the nickel content is an important factor affecting the safety performance of the battery. As the nickel content decreases, the safety performance will gradually improve, but the energy density will also decrease. In view of the above problems, the medium nickel 6-series material has obvious adva...

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Problems solved by technology

Now the ternary material of medium nickel also has its own disadvantages. Due to factors such as damage to the internal structure and side reactions between the surface material and the electrolyte after long-term circulation, its cycle performance is seriously attenuated. Coating a layer of oxide to change its cycle performance

[0003] CN109301243A discloses a new system of layered nickel-cobalt-titanium ternary positive electrode material, which uses Ti element to replace Mn element. Because the Ti-O bond is stronger, the layered crystal structure of the ternary positive electrode material can be stabilized, thereby improving its cycle process. The structural stability in the medium makes the ternary cathode material exhibit excellent capacity retention, and it shows better stability in the nickel-cobalt-titanium ternary cathode material of the high-nickel system, but this material is limited to a certain extent The intercalation and extraction rate of lithium ions is affected, which affects its rate performance. Moreover, it is easy to lose powder during use, and its structure is easily damaged during cycling, which affects its cycle performance.

The spherical nickel-cobalt lithium manganese oxide prepared by it has a high bulk density, its average particle size is 3-7μm, and the tap density can reach 2.25-2.50g / cm 3 , the reversible specific capacity can reach 172-185mAh / g, the process of preparing the precursor is cumbersome, the reaction process is difficult to control and the precursor material with various shapes cannot be made, and the shape of the ternary cathode material is relatively simple

[0005] The ternary cathode materials prepared by the above schemes all have disadvantages such as poor rate performance, poor cycle performance, and cumbersome preparation process. Therefore, it is very necessary to develop a ternary cathode material with a simple preparation process and high cycle performance and rate performance. of

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