A silicon-doped negative electrode sheet and a lithium-ion battery comprising the negative electrode sheet

A technology of negative electrode sheet and negative electrode, which is applied in the field of silicon-doped negative electrode sheet and lithium ion battery including the negative electrode sheet, and can solve the problems of poor conductivity and affecting battery cycle performance, etc.

Active Publication Date: 2021-07-06
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the conductivity of silicon-based materials is poor, which seriously affects the cycle performance of batteries assembled from silicon-doped negative electrodes.

Method used

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  • A silicon-doped negative electrode sheet and a lithium-ion battery comprising the negative electrode sheet
  • A silicon-doped negative electrode sheet and a lithium-ion battery comprising the negative electrode sheet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] (1) Preparation of negative electrode sheet

[0054] (1-1) Preparation of the first negative electrode active material layer slurry

[0055] Graphite (D 50 14.6μm), silicon oxide material (D 50 6.6 μm), conductive agent, binder (SBR) and dispersant (sodium carboxymethyl cellulose) are mixed according to the mass ratio of 91:5:0.5:2:1.5, then add water and stir to make the solid content of 37 - 50wt% negative electrode slurry A. That is, in the negative electrode slurry A, the graphite accounts for 94.8 wt% of the negative electrode active material, and the silicon-based material accounts for 5.2 wt% of the negative electrode active material. The conductive agent is 0.4wt% conductive carbon black+0.1wt% carbon nanotube (the aspect ratio is 8000, and the specific surface area is 780m 2 / g).

[0056] (1-2) Preparation of the second negative electrode active material layer slurry

[0057] Graphite (D 50 14.6μm), silicon oxide material (D 50 6.6 μm), conductive agent...

Embodiment 2-11 and comparative example 1-3

[0067] The preparation of the lithium ion battery of embodiment 2-7 and comparative example 1-3 is the same as embodiment 1, and the difference is that the selection of carbon nanotubes is different, as shown in table 1; Only one layer of slurry was coated on one side of the negative electrode current collector, and the thickness of the negative electrode active material layer formed by the slurry was 180 μm.

Embodiment 8-11

[0068] Examples 8-11 Lithium-ion batteries are prepared the same as Example 1, except that the amount of conductive carbon black or carbon nanotubes is different, see Table 1 for details.

[0069] In the negative electrode sheets of Examples 2-11 and Comparative Example 1, both surfaces of the negative electrode current collector are coated with two layers of slurry, and the sum of the thicknesses of the two layers of negative electrode active material layers formed by the two layers of slurry is 180 μm .

[0070] The composition of the negative electrode sheet in the lithium ion battery of table 1 embodiment 1-11 and comparative example 1-3

[0071]

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Abstract

The invention provides a silicon-doped negative electrode sheet and a lithium ion battery comprising the negative electrode sheet. In the present invention, two layers of silicon-doped negative electrode slurry with different aspect ratios of carbon nanotubes are respectively coated on the surface of the negative electrode current collector through double-layer coating equipment, and two layers of silicon-doped negative electrode active materials with different aspect ratios of carbon nanotubes are prepared. layer; wherein, the aspect ratio of the carbon nanotubes used in the first negative electrode active material layer close to the negative electrode current collector is greater than the aspect ratio of the carbon nanotubes used in the second negative electrode active material layer away from the negative electrode current collector. Compared with the disclosed single-layer coated silicon-doped negative-electrode lithium-ion battery, the lithium-ion battery of the present invention can greatly improve the cycle performance of the silicon-doped negative-electrode lithium-ion battery without losing energy density.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a silicon-doped negative electrode sheet and a lithium ion battery including the negative electrode sheet. Background technique [0002] With the gradual improvement of people's performance requirements for mobile phones, notebook computers and other electronic products, the rapid development of lithium-ion batteries is particularly important. In order to improve the energy density of lithium-ion batteries, the use of silicon-based materials in anode materials is one of the development trends in the industry. However, the poor conductivity of silicon-based materials seriously affects the cycle performance of batteries assembled from silicon-doped negative electrodes. Contents of the invention [0003] The study found that in order to increase the energy density of the battery, it is an effective solution to use a high-capacity silicon-based material m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/133H01M4/134H01M4/583H01M4/62H01M10/0525H01M4/02
CPCH01M4/133H01M4/134H01M4/583H01M4/625H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 宋博彭冲余正发李俊义徐延铭
Owner ZHUHAI COSMX BATTERY CO LTD
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