Negative pole piece, electrochemical device containing the negative pole piece and electronic device

A technology of negative electrode sheet and negative electrode material layer, which is applied in the field of electrochemistry, can solve problems such as shedding, affecting the electrochemical performance of lithium-ion secondary batteries, and negative electrode material rupture, so as to alleviate lithium intercalation expansion, improve cycle performance, and improve expansion. deformation effect

Pending Publication Date: 2021-08-06
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the volume change rate of silicon-based materials is as high as 300% or more in the process of lithium intercalation and deintercalation, which can easily cause the negative electrode material to crack and fall off, thereby affecting the electrochemical performance of lithium-ion secondary batteries.

Method used

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  • Negative pole piece, electrochemical device containing the negative pole piece and electronic device
  • Negative pole piece, electrochemical device containing the negative pole piece and electronic device
  • Negative pole piece, electrochemical device containing the negative pole piece and electronic device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0086]

[0087] Put a porous carbon material with a porosity of 38% in a closed silicon-containing gas reactor, heat it to 500°C and keep it warm for 4 hours, and after cooling, sieve and demagnetize to obtain the porosity α of silicon-based particles 1 It is 16% silicon-based particles, wherein the carbon content of the silicon-based particles is 60wt%, and the silicon content B in the silicon-based particles is 40wt%.

[0088]

[0089] Mix the negative electrode active material prepared above, graphite particles and nano conductive carbon black according to the mass ratio of 30:66.5:3.5 to obtain the first mixture; add the first mixture and the binder PAA according to the mass ratio of 95:5 to deionized In water, it is prepared into a slurry with a solid content of 45%, and stirred evenly to obtain the first mixed slurry; the first mixed slurry is uniformly coated on one surface of a negative electrode current collector copper foil with a thickness of 8 μm, and dried in t...

Embodiment 2

[0099] Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Example 10, Example 11, Example 12, Example 13, Example 14. In Example 15, Example 16 and Example 17, , , , , and are the same as in Example 1, and the changes of relevant preparation parameters are shown in Table 1:

[0100] Table 1

[0101]

Embodiment 18

[0103]

[0104] 1) Put a porous carbon material with a porosity of 38% in a closed silicon-containing gas reactor, heat it to 500°C and keep it warm for 4 hours, and after cooling, sieve and demagnetize to obtain the porosity of silicon-based particles alpha 1 It is 16% silicon-based particles, wherein the carbon content of the silicon-based particles is 60wt%, and the silicon content B in the silicon-based particles is 40wt%.

[0105] 2) Add the silicon-based particles obtained in 1) to single-walled carbon nanotubes (SCNT) containing carboxymethylcellulose sodium (CMC-Na) dispersant and disperse for 2 hours until a uniform mixed solution is formed, and spray dry to obtain powder, crushed, and sieved with 400 meshes to obtain the negative electrode material, wherein the mass ratio of silicon-based particles: SCNT: sodium carboxymethylcellulose is 99.75:0.1:0.15.

[0106] , , , , are the same as in Example 2.

[0107] Example 19, Example 20, Example 21, Example 22, Exampl...

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Abstract

Disclosed are a negative pole piece, an electrochemical device containing the negative pole piece and an electronic device. As a negative electrode material layer of the negative pole piece contains silicon-based particles and graphite particles, pores are created in the silicon-based particles, so that the porosity alfa 1 of the silicon-based particles and the silicon content B in the silicon-based particles satisfy P=0.5alfa 1/( B-alfa1B), 0.2<=P<=1.6, can effectively alleviate the lithium-intercalation expansion of silicon-based particles, thereby improving cycle performance and expansion and deformation of electrochemical devices.

Description

technical field [0001] The present application relates to the field of electrochemistry, and specifically relates to a negative electrode sheet, an electrochemical device and an electronic device including the negative electrode sheet. Background technique [0002] Lithium-ion secondary batteries have the advantages of high energy storage density, high open circuit voltage, low self-discharge rate, long cycle life, and good safety. They are widely used in various fields such as electric energy storage, mobile electronic equipment, electric vehicles, and aerospace equipment. With the rapid development of mobile electronic devices and electric vehicles, the market has put forward higher and higher requirements for the energy density, safety, cycle performance and service life of lithium-ion secondary batteries. [0003] Since the theoretical capacity of silicon-based materials reaches 4200mAh / g, it is currently known as the negative electrode material with the highest theoreti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/133H01M4/1393H01M4/1395H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/134H01M4/133H01M4/1393H01M4/1395H01M4/386H01M4/583H01M4/625H01M10/0525Y02E60/10H01M4/364H01M4/366H01M4/483H01M4/587H01M2004/021H01M2004/027
Inventor 廖群超
Owner NINGDE AMPEREX TECH
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