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Porous carbon silicon composite material and preparation method thereof

A silicon composite material, porous carbon technology, applied in non-aqueous electrolyte battery electrodes, electrical components, electrochemical generators, etc., can solve problems such as strong grain stress load, and achieve good stability.

Active Publication Date: 2014-06-04
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when using silicon as an anode, the intercalation and deintercalation of lithium is also accompanied by a very large volume expansion, which leads to very strong grain stress loading and thus to particle fragmentation and chalking

Method used

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  • Porous carbon silicon composite material and preparation method thereof
  • Porous carbon silicon composite material and preparation method thereof
  • Porous carbon silicon composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Sucrose was chosen as the carbon precursor and nano-sized calcium carbonate particles were chosen as the template. According to the weight ratio of 60:40, the nano calcium carbonate particles were impregnated with sucrose. The impregnated template was heated continuously at 225oC for 1 hour, then at 500oC for 2 hours, the calcium carbonate template was removed with 8% hydrochloric acid, and finally at 900oC for 4 hours, thereby obtaining porous carbon for deposition of silicon particles . Figure 5a is an SEM image of the porous carbon. During the above continuous heating process, the sucrose is carbonized, Figure 9 is the thermogravimetric image of the impregnated template after heating at 225oC for 1 hour and then at 500oC for 2 hours.

[0063] Silicon is deposited onto the porous carbon by chemical vapor deposition. Specifically, the obtained porous carbon was placed in a flat-tube furnace, and silane with a purity of 99.999% was carried by argon gas for 2 hours...

Embodiment 2

[0070] The difference between this example and Example 1 is that the chemical vapor deposition is carried out for 1.75 hours, that is, the argon gas carries silane with a purity of 1.75 hours and enters a flat tube heated to 450oC at a rate of 100 standard cubic centimeters per minute for 1.75 hours. inside the furnace. The thus prepared porous carbon-silicon composites have a pore size range of 20-90 nm, a pore volume of 0.52 cc / g, and a BET specific surface area of ​​211.2 m. 2 / g.

[0071] The porous carbon-silicon composite material is used to prepare electrodes in a conventional manner. The prepared electrode was used as the positive electrode of the test battery, lithium metal was used as the negative electrode of the test battery, and 1 mol / l LiPF 6 / EC:DMC:EMC is used as the electrolyte to make a button cell. Figure 15 is the tested charge-discharge cycle performance curve of the battery under constant current.

Embodiment 3

[0073] The difference between this example and Example 1 is that the chemical vapor deposition is carried out for 2 hours and the speed of the high-purity silane carried by the argon gas entering the flat tube furnace is 120 standard cubic centimeters per minute, that is, the purity carried by the argon gas is 120 standard cubic centimeters per minute. Silane at 120 standard cubic centimeters per minute for 2 hours into a flat-tube furnace heated to 450oC. The thus prepared porous carbon-silicon composites have a pore size range of 20-90 nm, a pore volume of 0.21 cc / g, and a BET specific surface area of ​​48.3 m. 2 / g.

[0074] The porous carbon-silicon composite material is used to prepare electrodes in a conventional manner. The prepared electrode was used as the positive electrode of the test battery, lithium metal was used as the negative electrode of the test battery, and 1 mol / l LiPF 6 / EC:DMC:EMC is used as the electrolyte to make a button cell. Figure 19 is the tes...

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Abstract

The invention provides a porous carbon silicon composite material able to be used in lithium battery cathodes. The porous carbon silicon composite material comprises porous carbon and silicon particles attached to the pore walls of the porous carbon. In terms of the total weight, the porous carbon silicon composite material comprises 20-70wt% of silicon and 80-30wt% of porous carbon, and the porous carbon silicon composite material has a BET (Brunauer-Emmett-Teller) specific surface area of 50-250m<2> / g and a pore volume of 0.2-0.6cc / g. The porous carbon silicon composite material has relatively large mass specific capacity and good circulation.

Description

technical field [0001] The present invention generally relates to materials and preparation methods thereof, and more specifically, the present invention relates to carbon-silicon composite materials and preparation methods thereof. Background technique [0002] Lithium-ion batteries are energy storage devices that have attracted much attention. In recent years, lithium-ion batteries have been widely used in portable electronic devices, and their applications in vehicles such as automobiles have also attracted much attention. [0003] The working principle of a lithium-ion battery is roughly as follows: when the battery is charged, the anode (that is, the negative electrode) absorbs lithium ions from the cathode, and absorbs electrons from the external circuit through the charging device, and releases these ions and electrons back to the cathode when the battery is discharged. The mass-specific capacity is an important parameter for anode materials because it determines the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/134H01M4/133H01M10/0525
CPCY02E60/122H01M4/13H01M4/362H01M4/364H01M10/0525Y02E60/10
Inventor 邱新平郭勋刘源张敬君周龙捷窦玉倩
Owner TSINGHUA UNIV
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