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Podiform silicon @ amorphous carbon @ graphene nanoscroll composite material for lithium ion battery negative material

A lithium-ion battery and composite material technology, applied in the field of pod-shaped silicon@amorphous carbon@graphene nano-roll composite materials, can solve the problems of easy cracking of the carbon protective layer, avoid pulverization, maintain integrity, and improve storage capacity. Effect of Lithium Capacity

Inactive Publication Date: 2016-08-17
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among the above-mentioned silicon / carbon composite materials, only egg yolk-eggshell silicon / carbon nanostructures can effectively buffer the volume expansion of silicon during charging and discharging, but its carbon protective layer is still easily broken and hydrofluoric acid is required in the preparation process. other dangerous chemicals
In this context, it is still a huge challenge to develop a green and low-cost preparation process for egg yolk@eggshell silicon / carbon composites with better performance

Method used

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  • Podiform silicon @ amorphous carbon @ graphene nanoscroll composite material for lithium ion battery negative material
  • Podiform silicon @ amorphous carbon @ graphene nanoscroll composite material for lithium ion battery negative material
  • Podiform silicon @ amorphous carbon @ graphene nanoscroll composite material for lithium ion battery negative material

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Take 500mg of commercial silicon nanopowder and stir and disperse it in absolute ethanol at a stirring rate of 200-1000rpm to form a uniform suspension. Then add 25mL Tris-HCl (10mM, pH=8.5) buffer solution and 50mg dopamine, After stirring and reacting at room temperature for 24 hours, the remaining unreacted dopamine was removed by filtration. The filtered product was washed repeatedly with distilled water and ethanol and dried in a vacuum oven for 24 hours. The dopamine-modified silicon nanopowder was named silicon@dopamine. Take 100mL graphene suspension (0.05mg / mL), add 73.5μL hydrazine hydrate to 60 o Reduce graphene under C conditions for 30 minutes, then add 5mg of silicon@dopamine prepared in the above steps, stir and heat for 10 minutes, transfer the above mixed suspension to a tubular plastic container, freeze, and place in a freeze dryer to vacuum freeze Lyophilization; the lyophilized silicon@dopamine@graphene nano-volume cylindrical body is annealed in a red...

Embodiment 2

[0033] Take 100mL graphene suspension (0.05mg / mL), add 73.5μL hydrazine hydrate to 60 o Reduce graphene under C condition for 30 minutes, then add 10mg of silicon@dopamine powder prepared in Example 1, stir and heat for 10 minutes, transfer the above mixed suspension to a tubular plastic container, freeze and place it in lyophilization Freeze and freeze-dry in a vacuum machine; the freeze-dried silicon@dopamine@graphene nano-volume cylindrical body is annealed in a reducing atmosphere at a temperature of 700 o C, the annealing time is 2 hours, and the composite material is taken out after natural cooling, which is the silicon@amorphous carbon@graphene nanovolume composite material. The thermogravimetric analysis results show that the actual mass fraction of silicon in the composite material is 73.6%.

[0034] According to the electrode preparation method in Example 1, the prepared silicon@amorphous carbon@graphene nanovolume composite material, acetylene black conductive agent, an...

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Abstract

The invention discloses a podiform silicon @ amorphous carbon @ graphene nanoscroll composite material for a lithium ion battery negative material. The podiform silicon @ amorphous carbon @ graphene nanoscroll composite material is prepared from the following steps: stirring and dispersing commercial silicon nano powder into absolute ethyl alcohol, adding a Tris-HCl buffer solution and dopamine in sequence, washing a product obtained after stirring with distilled water and ethanol, and drying in a vacuum drying oven so as to obtain silicon @ dopamine powder; adding the silicon @ dopamine powder into graphene suspension, adding hydrazine hydrate, heating so as to reduce graphene, subsequently transferring the mixed suspension into a liquid nitrogen environment for rapidly freezing, and performing vacuum freeze-drying so as to obtain silicon @ dopamine graphene nanoscroll columns; and performing annealing reduction on the freeze-dried silicon @ dopamine graphene nanoscroll columns a reductive atmosphere, thereby transforming dopamine into amorphous carbon. Due to the structure of the composite material disclosed by the invention, completeness of a podiform structure is maintained, the lithium storage capacity and the rate capability of the composite matieral are increased, and the circulation stability of the composite material is improved.

Description

Technical field [0001] The invention relates to a pod-like silicon@amorphous carbon@graphene nano-volume composite material used for a lithium ion battery negative electrode material, and belongs to the field of lithium ion battery negative electrode materials. Background technique [0002] The rapid development of portable electronic devices, wearable devices, and electric vehicles has placed increasing demands on energy storage devices. Among many energy storage devices, lithium-ion batteries are favored by consumers for their high-quality energy density, volumetric energy density, small self-discharge, no memory effect, wide working range, and maintenance-free. The current commercial lithium-ion battery anode materials are mainly graphite-based carbon anode materials, but their specific capacity is only 372mAh / g, and their lithium-intercalation potential platform is close to metal lithium, which is prone to "lithium dendrites" during rapid charge and discharge. "The phenomeno...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0525H01M4/583H01M4/38H01M4/139H01M4/1393H01M4/1395B82Y30/00
CPCB82Y30/00H01M4/139H01M4/1393H01M4/1395H01M4/362H01M4/386H01M4/583H01M10/0525Y02E60/10
Inventor 李小成万柳
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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