Conductive polymer-coated silicon-based negative electrode sheet, and preparation method and application thereof

A conductive polymer, silicon-based anode technology, applied in negative electrodes, battery electrodes, active material electrodes, etc., can solve the problems of harsh synthesis conditions, safety risks, poor cycle performance, etc., and achieve a wide range of liquid temperature and environmental friendliness. , the effect of improving Coulomb efficiency

Active Publication Date: 2020-02-07
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

JeeHoYom et al [Yom J H, Sun W H, Cho S M, et al.Improvement of irreversible behavior of SiO anodes for lithium ion batteries by a solid state reaction at high temperature[J].Journal of Power Sources,2016,311:159-166.] Through the solid-state reaction of SiO and lithium metal, carbon coating is carried out to prepare high-first-efficiency silicon-based negative electrode materials. This method improves the first-time Coulombic efficiency of the material, but the cycle performance of the material is relatively poor. Due to the use of lithium metal as the reaction The synthesis conditions are relatively harsh, and there is a safety risk, and there is a risk of gas production during the battery slurry process

Method used

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  • Conductive polymer-coated silicon-based negative electrode sheet, and preparation method and application thereof
  • Conductive polymer-coated silicon-based negative electrode sheet, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The commercialized SiO / C material (600mAh / g in Example 1) is mixed with conductive agent and binder according to the mass ratio of 94.5:2:3.5, coated, rolled, slitting, and die-cutting. A silicon-based negative electrode sheet is obtained.

[0028] Dissolve 1mol LiCl in 1L 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF 4]), add 1 mol of pyrrole (py) monomer, magnetically stir to dissolve and disperse evenly to obtain a mixed solution. Add the above mixed solution, silicon-based negative electrode sheet, and metal lithium sheet into the electrolytic cell respectively, apply an external power supply, control the voltage to 0.5V, and the reaction time is 6h. Carry out electrochemical self-polymerization reaction, and generate a conductive polymer film with a thickness of 20nm on the surface of the silicon-based negative electrode sheet; after the reaction, use the silicon-based negative electrode sheet as the positive electrode and the metal lithium sheet as the...

Embodiment 2

[0034] The commercialized SiO / C material (420mAh / g in Example 2) is mixed with conductive agent and binder according to the mass ratio of 94.5:2:3.5, coated, rolled, slitting, die-cutting, A silicon-based negative electrode sheet is obtained.

[0035] Take 1mol LiPF 6 Dissolve in 1L 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIm][PF 6 ]), add 1 mol of pyridine monomer, magnetically stir to dissolve and disperse evenly to obtain a mixed solution. Add the above mixed solution, silicon-based negative electrode sheet, and metal lithium sheet into the electrolytic cell respectively, apply an external power supply, control the voltage to 2V, and the reaction time is 0.5h. Carry out electrochemical self-polymerization reaction, and generate a conductive polymer film with a thickness of 1nm on the surface of the silicon-based negative electrode sheet. After the reaction is completed, the silicon-based negative electrode sheet is used as the positive electrode, and the lithiu...

Embodiment 3

[0037] The commercialized SiO / C material (450mAh / g in Example 3) is mixed with conductive agent and binder according to the mass ratio of 94.5:2:3.5, coated, rolled, slitting, die-cutting, A silicon-based negative electrode sheet is obtained.

[0038] Take 1mol LiPF 6 Dissolve in 1L of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIm][OTf]), add 1mol of thiophene monomer, magnetically stir to dissolve and disperse evenly to obtain a mixed solution. Add the above mixed solution, silicon-based negative electrode sheet, and metal lithium sheet into the electrolytic cell respectively, apply an external power supply, control the voltage at 1.5V, and the reaction time is 4h. Carry out electrochemical self-polymerization reaction, and generate a conductive polymer film with a thickness of 50nm on the surface of the silicon-based negative electrode sheet. After the reaction is completed, use the silicon-based negative electrode sheet as the positive electrode and the lith...

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Abstract

The invention discloses a conductive polymer-coated silicon-based negative electrode sheet, and a preparation method and an application thereof. The silicon-based negative electrode sheet is used as amatrix, ionic liquid is used as a reaction medium, a polymer monomer generates an electrochemical self-polymerization reaction in a gap and on the surface of a matrix through an electrochemical polymerization reaction, and a conductive polymer film with a controlled thickness is formed on the surface of the matrix to improve the interfacial properties and the cycling stability of the silicon-based negative electrode sheet; and then the electrode sheet is used as a positive electrode, a metal lithium sheet is used as a negative electrode, an external circuit is connected to control the currentto perform electrochemical pre-lithium, so as to improve the first-time coulombic efficiency of the matrix, and the conductive polymer-coated silicon-based negative electrode sheet is prepared. During the electrochemical polymerization reaction, the thickness of the conductive polymer film can be controlled by electric quantity, no catalyst is needed, and mass production can be realized; and thereaction medium is the ionic liquid, which has almost no vapor pressure and a wide liquid temperature range, so compared with other organic / inorganic solvents, it is more environmentally friendly, green and pollution-free.

Description

technical field [0001] The invention belongs to the technical field of negative pole pieces for lithium batteries, and in particular relates to a conductive polymer-coated silicon-based negative pole piece and a preparation method and application thereof. Background technique [0002] With the development of electric vehicles and portable appliances, the demand for lithium-ion batteries with high energy density is also increasing. The theoretical specific capacity of traditional graphite anode materials is only 372mAh / g, which is difficult to meet market demand. The first gram capacity of silicon materials is 4200mAh / g, the lithium intercalation platform is higher, the earth's crust is abundant, and it is environmentally friendly, which has gradually attracted widespread attention of researchers. [0003] However, the volume expansion of silicon is as high as 300%. During the cycle, it will not only cause silicon to separate from the surrounding conductive carbon network to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1395H01M4/134H01M4/38H01M4/62H01M10/0525
CPCH01M4/1395H01M4/134H01M4/386H01M4/624H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 王辉王庆莉林少雄许家齐周勇岐辛昱高玉仙
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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