Lithium ion battery negative electrode, preparation method and application thereof

A lithium-ion battery and negative electrode technology, applied in the field of lithium-ion battery negative electrode and its preparation, can solve the problems of decreased cycle stability, reduced electrical contact, active material shedding, etc., to improve structural stability and electrochemical stability, improve The effect of efficient transmission

Active Publication Date: 2020-06-09
XI AN JIAOTONG UNIV
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the intercalation / delithiation process of silicon, the volume expansion is as high as about 400%. The huge volume change will easily lead to the pulverization of the silicon electrode during the charge-discharge cycle and the active material will fall off from the current collector, thereby reducing the contact between the silicon electrode and the current collector. At the same time, a new solid electrolyte interface (SEI) film is continuously formed, causing the electrode capacity to decay and the cycle stability to decline rapidly

Method used

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  • Lithium ion battery negative electrode, preparation method and application thereof
  • Lithium ion battery negative electrode, preparation method and application thereof
  • Lithium ion battery negative electrode, preparation method and application thereof

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preparation example Construction

[0036] The specific preparation method of above-mentioned negative electrode of lithium ion battery and lithium ion button battery comprises the following steps:

[0037] Step 1, mix the negative electrode active material, conductive agent and base binder solution, ball mill in a planetary ball mill for 1 hour to obtain a uniformly mixed slurry, and use an automatic film coating machine to evenly coat the above slurry on the copper foil current collector, The coating thickness is 25 μm or 50 μm, and the initial electrode is obtained after vacuum drying at 60°C; the coating polymer solution is quantitatively coated on the surface of the initial electrode, and after vacuum drying at 120°C for 2 hours, a double-layer adhesive-wrapped negative electrode is obtained The negative electrode of the structure of active material; Wherein, the mass ratio of negative electrode active material, conductive agent and binding agent total amount is: (70~95): (15~4): (15~1); The mass ratio of l...

Embodiment 1

[0051] Use the method designed in the present invention to prepare the nano-silicon negative electrode of lithium ion battery, wherein the mass ratio of base binder and coating polymer is (1:1);

[0052] Nano-silicon particles and Super-P conductive carbon black were dispersed into the base binder polyacrylic acid (PAA) aqueous solution, and ball milled in a planetary ball mill for 1 h to make them fully mixed to obtain a uniformly mixed negative electrode slurry. An automatic coating machine was used to coat the slurry on a copper foil current collector with a coating thickness of 25 μm, and dried at 60° C. to remove moisture to obtain an initial electrode. Then, the coating polymer ion-conducting polyurethane (B1) was quantitatively coated on the surface of the initial electrode, and dried at 120° C. for 2 hours to obtain the final electrode. The mass ratio of nano-silicon, conductive carbon black, base binder and coating polymer is 70:15:7.5:7.5. The above electrode was cu...

Embodiment 2

[0057] Use the method designed in the present invention to prepare the nano-silicon negative electrode of lithium ion battery, wherein the mass ratio of base binder and coating polymer is (1:2);

[0058] Nano-silicon particles and Super-P conductive carbon black were dispersed into the base binder polyacrylic acid (PAA) aqueous solution, and ball milled in a planetary ball mill for 1 h to make them fully mixed to obtain a uniformly mixed negative electrode slurry. An automatic coating machine was used to coat the slurry on a copper foil current collector with a coating thickness of 25 μm, and dried at 60° C. to remove moisture to obtain an initial electrode. Then, the coating polymer ion-conducting polyurethane (B1) was quantitatively coated on the surface of the initial electrode, and dried at 120° C. for 2 h to obtain the final electrode. The mass ratio of nano-silicon, conductive carbon black, base binder and coating polymer is 70:15:5:10. The above electrode was cut into ...

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Abstract

The invention discloses a lithium ion battery negative electrode and a preparation method and application thereof. The lithium ion battery negative electrode with stable structure and performance is constructed through a simple method, and the problems of electrode structure degradation and solid-phase electrolyte interface instability are effectively improved. In the preparation of the negative electrode, a substrate adhesive and a coating polymer are used; the substrate adhesive firmly bonds a negative electrode active material through chemical interaction; on one hand, the coating polymer permeates into the electrode to wrap the active material particles for the second time; on the other hand, due to good elasticity, ion conductivity and other functions of the coating polymer, mechanical and chemical protection is provided for the electrode, the construction of an SEI film and the effective transmission of lithium ions between the electrode and an electrolyte can be effectively improved, and the electrochemical stability of the electrode is improved.

Description

technical field [0001] The invention belongs to the technical field of energy batteries, and in particular relates to a negative electrode of a lithium ion battery and a preparation method and application thereof. Background technique [0002] With the rapid development of society, lithium-ion batteries with advantages such as high energy density, high working voltage, low self-discharge rate, long service life, environmental friendliness, and high safety have been widely used in power sources and energy storage systems. application. [0003] At present, the most widely used commercial lithium-ion battery anode material is graphitic carbon material. The lamellar structure makes the volume expansion smaller after lithium intercalation, and has the advantages of low redox potential, high Coulombic efficiency, and long cycle life. However, the theoretical specific capacity of the traditional graphite negative electrode is only 372mAh / g, and the low specific capacity can no lon...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/38H01M4/134H01M4/1395H01M10/0525
CPCH01M4/134H01M4/1395H01M4/386H01M4/622H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 宋江选殷建青焦星星
Owner XI AN JIAOTONG UNIV
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