Negative electrode material and preparation method thereof, and lithium ion battery comprising negative electrode material

A negative electrode material and carbon material technology, applied in the field of negative electrode materials and their preparation, can solve the problems of large thickness expansion and fast capacity decay

Pending Publication Date: 2021-11-02
ZHUHAI COSMX BATTERY CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to improve the shortcomings of the existing silicon-based negative electrode materials for lithium-ion batteries, such as rapid capacity decay and large thickness expansion during cycling, a negative electrode material, a preparation method thereof, and a lithium-ion battery including the negative electrode material are provided.

Method used

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  • Negative electrode material and preparation method thereof, and lithium ion battery comprising negative electrode material
  • Negative electrode material and preparation method thereof, and lithium ion battery comprising negative electrode material
  • Negative electrode material and preparation method thereof, and lithium ion battery comprising negative electrode material

Examples

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Effect test

Embodiment 1

[0066] Under an inert atmosphere, ball mill the pure silicon material to obtain Si powder; the BET specific surface area of ​​the pure silicon material is ~0.1m 2 / g, D of PSA test v 50 is ~100 μm. The BET specific surface area of ​​the Si powder is 9.4m 2 / g, PSA test D v 50 is 0.8 μm.

[0067] Polynaphthalene with an average molecular weight of 5000 was dissolved in toluene, and the above-mentioned Si powder was added to coat the surface of the Si powder with polynaphthalene. The mass ratio of polynaphthalene to Si powder was 15:85, and the first composite material was obtained after drying.

[0068] Put the above-mentioned first composite material into a high-temperature furnace, protect it with argon, raise the temperature to 250°C at a heating rate of 3°C / min, and keep it for 3 hours, and raise the temperature to 600°C at a heating rate of 3°C / min, and keep 3h, cool down naturally to obtain the second composite material.

[0069] Grinding the second composite materia...

Embodiment 2

[0077] This example is basically the same as Example 1, except that polyanthracene with an average molecular weight of 5,000 is used in the preparation of the negative electrode material instead of polynaphthalene with an average molecular weight of 5,000.

Embodiment 3

[0079] This embodiment is basically the same as Embodiment 1, except that FeSi material is used in the negative electrode material preparation process instead of pure silicon material.

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Abstract

The invention provides a negative electrode material and a preparation method thereof, and a lithium ion battery comprising the negative electrode material. The negative electrode material comprises a silicon-based material and a coating coated on the surface of the silicon-based material. The coating is obtained by pyrolyzing a polymer containing rich planar conjugated bonds. The coating retains a part of the polymer structure, and the degree of order of carbon atoms is high. Unpaired electrons of Si on the surface of the negative electrode material are reserved, and a dangling bond of Si and a conjugate pi bond of the coating have strong interaction. Due to the characteristics, the negative electrode material has a highly stable interface structure, and the lithium ion battery comprising the negative electrode material has the advantages of high cycle coulombic efficiency, slow capacity retention rate attenuation, small thickness swelling rate and the like.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative electrode material, a preparation method thereof and a lithium ion battery comprising the negative electrode material. Background technique [0002] In areas such as consumer electronics and electric vehicles, the requirements for battery life continue to increase. Correspondingly, lithium-ion batteries as energy donors must have higher energy density. At present, the negative electrode material of commercial lithium-ion batteries is graphite, and its theoretical gram capacity is 372mAh / g. In actual use, it can reach 350-360mAh / g, indicating that its capacity is close to the limit, but this still cannot meet the energy density of the battery. Continue to increase demand. [0003] Silicon is abundant in the earth's crust. At room temperature, the lithium-deintercalation capacity of silicon materials can reach 3579mAh / g, which is about ten time...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/48H01M4/62H01M10/0525C01B32/05C01B32/15C01B33/02C01B33/18
CPCH01M4/366H01M4/386H01M4/483H01M4/625H01M4/628H01M10/0525C01B33/02C01B33/18C01B32/05C01B32/15C01P2004/80C01P2006/40H01M2004/021H01M2004/027Y02E60/10
Inventor 范洪生艾新平汪辉薛佳宸李素丽
Owner ZHUHAI COSMX BATTERY CO LTD
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