Composite silicon-carbon electrode material with shelly structure

A silicon-carbon composite, electrode material technology, applied in battery electrodes, structural parts, circuits, etc., can solve the problems of fast capacity decay, limited electron conduction rate, easy fragmentation, etc., to achieve fast charge and discharge rate, shorten the transmission path. , the effect of long service life

Inactive Publication Date: 2018-04-20
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, traditional carbon materials are prone to fragmentation during silicon cycling, resulting in faster capacity decay after a large number of cycles, and amorphous carbon materials limit the electron conduction rate.

Method used

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  • Composite silicon-carbon electrode material with shelly structure
  • Composite silicon-carbon electrode material with shelly structure
  • Composite silicon-carbon electrode material with shelly structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] In this example, a material with silicon content accounting for 28 wt% of the material mass was prepared.

[0036] figure 1 Demonstrated the preparation process of "shell-like" structure silicon-carbon composite electrode materials by vacuum filtration method, in which SiNPs is nano-silicon particles (particle size 30-50nm), GO is graphene oxide, rGO is reduced graphene oxide, CNT is carbon nanotube (diameter 8-10nm, length 8-15μm), SiO 2 It is a silicon dioxide layer naturally oxidized on the surface of nano-silicon particles. The specific method is as follows:

[0037](1) Preparation of GO / CNT / SiNPs precursor solution: Take 50 mg of nano-silicon particles, carbon nanotubes, and graphene oxide and disperse them into 10 mL of aqueous solution to obtain an aqueous dispersion with a concentration of 5 mg / mL; : 3: 10 was ultrasonically mixed to obtain an aqueous solution mixture of 28 parts by mass of silicon nanoparticles, 17 parts by mass of carbon nanotubes, and 55 p...

Embodiment 2

[0043] In this embodiment, a material whose silicon content accounts for 35 wt% of the material mass is prepared. Step (1) is:

[0044] Preparation of GO / CNT / SiNPs precursor solution: Disperse 50 mg of nano-silicon particles, carbon nanotubes, and graphene oxide into 10 mL of aqueous solution to obtain an aqueous dispersion with a concentration of 5 mg / mL; the three aqueous dispersions were ultrasonically mixed in proportion, An aqueous solution mixture of 35 parts by mass of silicon nanoparticles, 15 parts by mass of carbon nanotubes, and 50 parts by mass of graphene oxide was obtained. Other operations are the same as in Example 1.

Embodiment 3

[0046] In this embodiment, a material whose silicon content accounts for 50 wt% of the material mass is prepared. Step (1) is:

[0047] Preparation of GO / CNT / SiNPs precursor solution: Disperse 50 mg of nano-silicon particles, carbon nanotubes, and graphene oxide into 10 mL of aqueous solution to obtain an aqueous dispersion with a concentration of 5 mg / mL; the three aqueous dispersions were ultrasonically mixed in proportion, An aqueous solution mixture of 50 parts by mass of silicon nanoparticles, 12 parts by mass of carbon nanotubes, and 38 parts by mass of graphene oxide was obtained. Other operations are the same as in Example 1.

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Abstract

The invention provides a composite silicon-carbon electrode material with a shelly structure. The composite silicon-carbon electrode material is composed of reduced graphene oxide, silicon nanoparticles and carbon nanotubes, wherein the silicon nanoparticles are dispersed among multiple layers of the reduced graphene oxide; gaps are left between the silicon nanoparticles and the reduced graphene oxide; and the carbon nanotubes prop open the reduced graphene oxide and allow the reduced graphene oxide to include the silicon nanoparticles like shells. The invention also provides preparation and application of the composite silicon-carbon electrode material with the shelly structure. According to the invention, the shelly structure is formed among the layers of the reduced graphene oxide, thecarbon nanotubes provides support among the layers of the reduced graphene oxide and spatial partition for the silicon nanoparticles, so reserved space is left for the volume expansion of silicon during charging and discharging of a battery, and the structural integrity of an active material of a negative electrode can be better maintained; and thus, the battery is allowed to have high capacity which is hard to attenuate, good cyclicity and long service life.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a carbon-silicon composite electrode material, its preparation method and application. Background technique [0002] Due to the advantages of high open circuit voltage, high energy density, low self-discharge rate and no pollution, lithium-ion batteries are widely used in electronic equipment, electric transportation, aerospace, military, medical and other fields. The charging and discharging process of lithium-ion batteries is based on the repeated intercalation and deintercalation of lithium ions between the positive and negative electrode materials. At present, commercial lithium-ion batteries mainly use carbon materials as negative electrodes, and graphite is the most widely used due to its layered structure that facilitates the intercalation and extraction of lithium ions. However, the theoretical specific capacity of graphite is only 372mAh / g, which is relative...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/62H01M10/0525
CPCH01M4/364H01M4/625H01M10/0525Y02E60/10
Inventor 王晓红匡宣霖
Owner TSINGHUA UNIV
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