Preparation method of composite cathode material SiOx@Si/C for lithium ion battery

A lithium-ion battery and negative electrode material technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as hindering practical application, low theoretical specific capacity, and poor electronic conductivity, and achieve excellent electrochemical performance and stable cycle performance. , the effect of suppressing volume expansion

Inactive Publication Date: 2014-08-20
YANGTZE UNIVERSITY
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Problems solved by technology

[0003] As the negative electrode material of the core components of lithium-ion secondary batteries, graphite materials are widely favored by businesses because of their excellent cycle performance, but their low theoretical specific capacity (372mAh g -1 ) limits its scope of use; although silicon-based materials have a higher theoretical specific capacity (4200mAh g -1 ) and a low voltage platform (0.02-0.60V), but its electronic conductivity is poor, the capacity fades quickly, and problems such as powdering of the electrode material due to 300% volume expansion are prone to occur during the charge-discharge cycle, which seriously hampers its practical application

Method used

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  • Preparation method of composite cathode material SiOx@Si/C for lithium ion battery
  • Preparation method of composite cathode material SiOx@Si/C for lithium ion battery
  • Preparation method of composite cathode material SiOx@Si/C for lithium ion battery

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Embodiment 1

[0025] Use tetraethyl orthosilicate as the silicon source, place the silicon source in an aqueous solution of ethanol, silicon source: water: absolute ethanol = 1:2:2; choose ammonia water as the catalyst, add it to the aqueous solution of ethanol; at 40°C Add glacial acetic acid to the aqueous solution of ethanol to adjust the pH value to 10, and after hydrolysis for 4 hours, prepare a sol solution of silicon oxide; add the dispersant polyvinylpyrrolidone to the obtained sol solution, stir, and then add nano silicon powder and sucrose , silicon source: sucrose: nano silicon powder = 2: 4: A, wherein: A = 0.3, 0.5, 0.7, 0.9; continue to stir; the resulting solution is centrifuged and vacuum dried to obtain the target product SiO x Precursor of Si / C; after washing, centrifuging and vacuum-drying the obtained precursor, it is placed in an argon tube-type atmosphere furnace successively at a low temperature of 100°C for 3 hours, at a medium temperature of 400°C for 6 hours and at ...

Embodiment 2

[0031] Take vinyltrimethylsilane as the silicon source, place the silicon source in an aqueous ethanol solution, silicon source: water: absolute ethanol = 1:2:2; choose ammonium bicarbonate as the catalyst, and add it to the aqueous ethanol solution; Add glacial acetic acid to the aqueous ethanol solution at 40°C to adjust the pH to 10, and after hydrolysis for 4 hours, prepare a sol solution of silicon oxide; add the dispersant sodium dodecylsulfonate to the obtained sol solution, stir, Then add nano-silica powder and glucose, silicon source: glucose: nano-silica powder = 2:4:0.5, and continue to stir; the resulting solution is centrifuged and vacuum-dried to obtain the target product SiO x Precursor of Si / C; after washing, centrifuging and vacuum-drying the obtained precursor, it is placed in an argon tube atmosphere furnace successively according to different low temperatures of 50°C, 100°C, 150°C and 200°C for 3 hours, and the medium temperature is 400°C. ℃ for 6 hours and...

Embodiment 3

[0037] Use tetraethyl orthosilicate as the silicon source, place the silicon source in an aqueous solution of ethanol, silicon source: water: absolute ethanol = 1:2:2; choose ammonia water as the catalyst, add it to the aqueous solution of ethanol; at 40°C Add glacial acetic acid to the aqueous solution of ethanol to adjust the pH value to 10, and after hydrolysis for 4 hours, prepare a sol solution of silicon oxide; add the dispersant triethanolamine to the obtained sol solution, stir, and then add nano silicon powder and urine aldehyde Resin, silicon source: urea-formaldehyde resin: nano-silica powder = 2:4:0.5, continue to stir; the resulting solution is centrifuged and vacuum-dried to obtain the target product SiO x Precursor of Si / C; after washing, centrifuging and vacuum drying, the resulting precursor is placed in an argon tube atmosphere furnace and kept at a low temperature of 100°C for 3 hours, with different medium temperatures of 300°C, 400°C, 500°C and 600°C ℃ for...

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Abstract

The invention relates to a preparation method of a composite cathode material SiOx@Si/C for a lithium ion battery. The preparation method is characterized by comprising the following steps: 1, putting a silicon source into an aqueous solution of ethanol, adding a catalyst and glacial acetic acid, adjusting pH value to 8.5-11.5, and carrying out a hydrolysis reaction for 4h to obtain an intermediate which is a uniform solution, sol or suspending liquid; 2, adding a dispersant into the intermediate and stirring; adding a nano-silicon powder and a carbon source and continuously stirring; carrying out centrifugal separation and vacuum drying on the obtained solution so as to obtain a precursor of the target product SiOx@Si/C; and 3, washing the precursor obtained, centrifuging and carrying out vacuum drying, putting the precursor into an argon tubular atmosphere furnace to carry out subsection pyrolysis, and carrying out furnace cooling to obtain the target product SiOx@Si/C. According to the composite cathode material prepared in the invention, volume expansion arising in the charge-discharge process can be effectively inhibited; initial charge/discharge efficiency reaches 73.8%; the composite cathode material has very excellent electrochemical performance and stable cycle performance; and the preparation technology is simple and easy to implement.

Description

Technical field: [0001] The invention relates to a lithium ion battery composite negative electrode material SiO x The preparation method of Si / C belongs to the technical field of lithium ion battery materials and preparation methods thereof. Background technique: [0002] Under the high-tech background of energy crisis and environmental pollution, as a new generation of clean energy, lithium-ion secondary batteries have high specific energy density, wide electrochemical working window and temperature range, low self- Due to the remarkable advantages of discharge efficiency, long service life and environmental friendliness, it has been widely used in small communication devices such as mobile phones, computers and cameras. [0003] As the negative electrode material of the core components of lithium-ion secondary batteries, graphite materials are widely favored by businesses because of their excellent cycle performance, but their low theoretical specific capacity (372mAh g ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/48H01M4/38H01M4/587
CPCH01M4/364H01M10/0525Y02E60/10
Inventor 肖围梅平苏明如缪畅刘云建颜学敏秦少雄
Owner YANGTZE UNIVERSITY
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