Silicon/graphene composite thin film electrode and preparation method thereof and lithium ion battery

A technology of graphene composite and graphene film, which is applied in the direction of electrode carrier/current collector, battery electrode, secondary battery, etc., can solve the problems of poor silicon cycle stability, detachment, uneven composite, etc., and achieve high rate performance and ratio The effect of high capacity and high specific capacity

Inactive Publication Date: 2018-04-03
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high chemical stability of graphene and silicon, it is difficult to form a strong binding force, resulting in uneven recombination and the separatio

Method used

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  • Silicon/graphene composite thin film electrode and preparation method thereof and lithium ion battery
  • Silicon/graphene composite thin film electrode and preparation method thereof and lithium ion battery
  • Silicon/graphene composite thin film electrode and preparation method thereof and lithium ion battery

Examples

Experimental program
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Example Embodiment

[0052] Correspondingly, the embodiment of the present invention provides a method for preparing a silicon / graphene composite film electrode, which includes the following steps:

[0053] S10. Provide a current collector, and subject the current collector to a negative electrification process to obtain a negatively charged current collector;

[0054] S20, providing a silicon material, and subjecting the silicon material to charge treatment to obtain a charged silicon material dispersion;

[0055] S30, providing graphene, and subjecting the graphene to a charge treatment to obtain a graphene dispersion liquid with an opposite charge to the silicon material;

[0056] S40. Immerse the negatively charged current collector alternately into the charged silicon material dispersion and the graphene dispersion opposite to the silicon material, and act on the negatively charged current collector through electrostatic attraction A silicon film layer and a graphene film layer are deposited on the t...

Example Embodiment

[0070] Example 1

[0071] A method for preparing a silicon / graphene composite film electrode includes the following steps:

[0072] S10. Perform negative charge treatment on the collector: soak the purified foamed copper collector in 2wt% Ca(OH) 2 Soak in ethanol aqueous solution (the volume ratio of ethanol to water is 1:3) for 20 minutes, and then repeatedly wash with ultrapure water to obtain a foamed copper current collector with a negative charge on the surface;

[0073] S20. The silicon material is positively charged: weigh 100mg of silicon nanoparticles (D50 is 200-300nm) and co-disperse with 100mg PDDA in 500mL deionized water, ultrasonically disperse for 30min; centrifuge the dispersion and wash it repeatedly with deionized water The precipitate is used to remove excess PDDA, and the washed product is dispersed in deionized water to prepare 100 mL of positively charged Si-PDDA dispersion;

[0074] S30. Perform negative charge treatment on graphene sheets: Disperse the reduced...

Example Embodiment

[0077] Example 2

[0078] A method for preparing a silicon / graphene composite film electrode includes the following steps:

[0079] S10. The current collector is subjected to negative charge treatment: the purified copper foil current collector is soaked in a 1wt% KOH ethanol aqueous solution (the volume ratio of ethanol to water is 2:3) for 5 minutes, and then repeatedly washed with ultrapure water. Obtain a copper foil current collector with a negative charge on the surface;

[0080] S20. The silicon material is subjected to positive charge treatment: weigh 500mg of silicon nanoparticles (D50 is 500nm) and co-disperse with 40mg PDDA in 200mL deionized water, ultrasonically disperse for 30 minutes; centrifuge the dispersion and repeatedly wash the precipitate with deionized water, To remove excess PDDA, disperse the washed product in deionized water to prepare 500 mL of positively charged Si-PDDA dispersion;

[0081] S30. Perform negative charge treatment on graphene sheets: Dispers...

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Abstract

The invention provides a silicon/graphene composite thin film electrode. The composite thin film electrode comprises a current collector and a silicon/graphene composite thin film formed on the current collector through electrostatic self-assembly; the silicon/graphene composite thin film comprises at least one silicon thin film layer and at least one graphene thin film layer which are stacked alternately; the silicon thin film layer is combined on the current collector or the graphene thin film layer through electrostatic attraction; and the graphene layer is combined on the current collectoror the silicon thin film layer through electrostatic attraction. The electrode has high structural stability, the electrode structure damage caused by silicon material expansion can be relieved effectively, and the cycle life of the battery can be prolonged; and the electrode has high specific capacity and high rate capability. The invention also provides a preparation method of the electrode, and a lithium ion battery comprising the electrode.

Description

technical field [0001] The invention relates to the technical field of battery electrode preparation, in particular to a silicon / graphene composite thin film electrode, a preparation method thereof, and a lithium ion battery. Background technique [0002] Compared with traditional secondary batteries, lithium-ion batteries have the advantages of high open circuit voltage, high energy density, long service life, small self-discharge, and no memory effect. They have been widely used in mobile electronic devices and electric vehicles. [0003] At present, the anode materials of lithium-ion batteries that have been commercialized are mainly carbon-based materials such as graphite, and their discharge capacity is basically around 350mAh / g, which cannot meet the demand for high energy density of lithium-ion batteries in the future. The silicon material has the largest known lithium intercalation capacity (4212mAh / g), which helps to increase the energy density of the battery, and i...

Claims

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Application Information

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IPC IPC(8): H01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/36H01M4/38H01M4/583H01M4/64H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/366H01M4/38H01M4/583H01M4/64H01M10/0525Y02E60/10
Inventor 杨婉璐王志勇夏圣安
Owner HUAWEI TECH CO LTD
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