A kind of lithium secondary battery silicon-carbon-polymer composite electrode and preparation method thereof

A lithium secondary battery, composite electrode technology, applied in battery electrodes, secondary batteries, active material electrodes, etc., can solve the problems of unstable structure, deterioration of cycle performance, poor conductivity, etc., and achieve simple methods and improve electrochemical activity. , the effect of high conductivity

Active Publication Date: 2021-09-28
北京理工大学重庆创新中心 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the poor conductivity and unstable structure of silicon-carbon composite electrodes in the prior art, which lead to the deterioration of cycle performance, one of the objectives of the present invention is to provide a silicon-carbon-polymer composite electrode for a lithium secondary battery, the composite electrode With good conductivity and stable electrode structure, it exhibits high specific capacity, high Coulombic efficiency and good battery cycle capacity retention

Method used

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  • A kind of lithium secondary battery silicon-carbon-polymer composite electrode and preparation method thereof
  • A kind of lithium secondary battery silicon-carbon-polymer composite electrode and preparation method thereof
  • A kind of lithium secondary battery silicon-carbon-polymer composite electrode and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Weigh 0.9g of micro-silicon and 0.1g of polyacrylonitrile (PAN) and grind and mix evenly, place in a sealed ball mill jar under the protection of an argon atmosphere, and ball mill for 2h at a speed of 350 rpm to obtain Si-PAN. Composite material; weigh 0.8g of Si-PAN composite material and 9.2g of graphite and grind and mix uniformly to obtain mixture 1; weigh 0.2g of polyacrylonitrile and dissolve it in 20mL of dimethylformamide (DMF) solvent to form Transparent mixed solution 2; add mixture 1 to mixed solution 2 and stir evenly with a magnetic stirrer, evaporate the solvent and transfer it to a 60°C oven for vacuum drying for 24 hours to obtain brown mixture 3; then place mixture 3 in argon In a tube furnace protected by gas atmosphere, sinter at 300°C for 12h, cool to a suitable temperature and grind to obtain a brown final composite material.

[0042] The XRD test shows that the silicon-carbon-polymer composite material prepared in Example 1 contains the characteri...

Embodiment 2

[0045] Weigh 0.9g of micro-silicon and 0.1g of polyacrylonitrile (PAN) and grind and mix evenly, place in a sealed ball mill jar under the protection of an argon atmosphere, and ball mill for 2h at a speed of 350 rpm to obtain Si-PAN. Composite material; weigh 0.8g of Si-PAN composite material and grind and mix with 6.48g of graphite to obtain mixture 1; weigh 0.2g of polyacrylonitrile and dissolve it in 20mL of dimethylformamide (DMF) solvent to form Transparent mixed solution 2; add mixture 1 to mixed solution 2 and stir evenly with a magnetic stirrer, evaporate the solvent and transfer it to a 60°C oven for vacuum drying for 24 hours to obtain brown mixture 3; then place mixture 3 in argon In a tube furnace protected by gas atmosphere, sinter at 300°C for 12h, cool to a suitable temperature and grind to obtain a brown final composite material.

[0046] The XRD test shows that the silicon-carbon-polymer composite material prepared in Example 1 contains the characteristic dif...

Embodiment 3

[0049]Weigh 0.9g of micro-silicon and 0.1g of polyacrylonitrile (PAN) and grind and mix evenly, place in a sealed ball mill jar under the protection of an argon atmosphere, and ball mill for 2h at a speed of 350 rpm to obtain Si-PAN. Composite material; weigh 0.8g of Si-PAN composite material and grind and mix with 4.0g of graphite to obtain mixture 1; weigh 0.2g of polyacrylonitrile and dissolve it in 20mL of dimethylformamide (DMF) solvent to form Transparent mixed solution 2; add mixture 1 to mixed solution 2 and stir evenly with a magnetic stirrer, evaporate the solvent and transfer it to a 60°C oven for vacuum drying for 24 hours to obtain brown mixture 3; then place mixture 3 in argon In a tube furnace protected by gas atmosphere, sinter at 300°C for 12h, cool to a suitable temperature and grind to obtain a brown final composite material.

[0050] The XRD test shows that the silicon-carbon-polymer composite material prepared in Example 1 contains the characteristic diffr...

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Abstract

The invention relates to a silicon-carbon-polymer composite electrode for a lithium secondary battery and a preparation method thereof, belonging to the technical field of negative electrode materials for lithium secondary batteries. The composite electrode is composed of cyclized conductive polyacrylonitrile chemically coated with nano-silicon to form a core-shell structure, and then compounded with graphite carbon material. Micron silicon and polyacrylonitrile (PAN) are ball-milled to form a nanocomposite, and the obtained composite and graphite are added to the PAN dimethylformamide (DMF) solvent and stirred evenly, and then the mixture is placed inert after drying Heat treatment in the atmosphere to obtain the final composite electrode material. The electrode material has high electrical conductivity, good chemical stability and structural stability. The preparation method is simple, the raw material cost is low, and large-scale production is easy to realize.

Description

technical field [0001] The invention relates to a silicon-carbon-polymer composite electrode of a lithium secondary battery and a preparation method thereof, belonging to the technical field of negative electrode materials of the lithium secondary battery. Background technique [0002] Lithium secondary batteries with high energy density are the research hotspots of next-generation lithium battery technology. Traditional lithium-ion batteries use graphite as the negative electrode, and its theoretical capacity is only 372mAh / g. The kinetic performance of graphite is poor, and its lithium intercalation platform is close to that of metal. Lithium is prone to "lithium separation" phenomenon during fast charging, which is likely to cause battery safety hazards. Therefore, graphite anodes will not be able to meet the requirements of the next generation of high energy density lithium secondary batteries. The theoretical capacity of the silicon negative electrode can reach 3572mAh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/134H01M4/133H01M4/587H01M4/62H01M4/1393H01M4/1395H01M10/0525
CPCH01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/587H01M4/622H01M4/624H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 谭国强王敬苏岳锋陈来吴锋
Owner 北京理工大学重庆创新中心
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