Carbon-silicon composite lithium ion battery cathode material and preparation method thereof

A lithium-ion battery, carbon-silicon composite technology, applied in battery electrodes, circuits, electrical components, etc., to achieve the effects of environmental friendliness, long service life, and low production costs

Inactive Publication Date: 2015-10-28
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Elemental silicon as an anode material has received more and more attention due to its very high theoretical specific capacity (Trill J H., Tao C.Q., Winter M., et al. J. Solid State Electrochem., 2011, 15:349-356.) It is considered to be one of the most likely materials to replace graphite anodes, but silicon-based anodes have not yet been put into commercial use

Method used

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  • Carbon-silicon composite lithium ion battery cathode material and preparation method thereof
  • Carbon-silicon composite lithium ion battery cathode material and preparation method thereof
  • Carbon-silicon composite lithium ion battery cathode material and preparation method thereof

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Embodiment 1

[0027] Si / SiO of the present invention 2 Preparation of / C semi-hollow composite structure

[0028] Add commercial Si to the mixed solution of ammonia water, deionized water and absolute ethanol with a volume ratio of 1:5:50, and add PVP (polyvinylpyrrolidone) with Si mass 1 / 10 for 10 minutes, and then add the volume of deionized water 5:1 ratio of TEOS (tetraethyl silicate). Stir for 1 h, wash with deionized water and absolute ethanol three times by centrifugation, and then dry in a drying oven at 60 ° C to obtain Si / SiO 2 composite structure product, figure 2 (c), (d) is the Si / SiO prepared by this embodiment 2 Sample transmission electron micrographs and high magnification transmission electron micrographs. Si / SiO 2 After the sample was mixed with PVDF (polyvinylidene fluoride) at a mass ratio of 10:1, NMP 20 times the mass of PVDF (N-methylpyrrolidone) was added, stirred, and then carbonized at 850 °C for 2 h under Ar atmosphere. Put the obtained product into 0.5Mol...

Embodiment 2

[0030] Add commercial Si to the mixed solution of ammonia water, deionized water and absolute ethanol with a volume ratio of 1:3.18:23.56, and add PVP with Si mass 1 / 5 for ultrasonication for 10 minutes, and then add deionized water with a volume ratio of 2:1 TEOS. Stir for 1 h, wash with deionized water and absolute ethanol three times by centrifugation, and then dry in a drying oven at 60 ° C to obtain Si / SiO 2 Composite structure product, the Si / SiO 2 After the sample was mixed with PVDF with a mass ratio of 6:1, NMP 20 times the mass of PVDF was added, stirred, and then carbonized at 650 °C for 2 h under Ar atmosphere. Put the obtained product into 0.5Mol / L HF and etch it for 1h, wash it with deionized water and absolute ethanol for five times, and dry it at 60°C. The obtained product is Si / SiO 2 / C semi-hollow composite structure. Si accounted for Si / SiO 2 The mass percent range of the / C part hollow composite structure is 63%. image 3 (a) Si / SiO prepared for this e...

Embodiment 3

[0032] Add commercial Si to ammonia water, put it into a mixed solution of deionized water and absolute ethanol with a volume ratio of 3:10:50, add PVP with Si mass 1 / 5 for ultrasonication for 10 minutes, and then add deionized water with a volume ratio of 1:1 TEOS. Stir for 1 h, wash with deionized water and absolute ethanol three times by centrifugation, and then dry in a drying oven at 60 ° C to obtain Si / SiO 2 Composite structure product, the Si / SiO 2 After the sample was mixed with PVDF with a mass ratio of 4:1, NMP with 10 times the mass of PVDF was added, stirred, and then carbonized at 700 °C for 2 h under Ar atmosphere. Put the obtained product into 0.5Mol / L HF and etch it for 1h, wash it with deionized water and absolute ethanol for five times, and dry it at 60°C. The obtained product is Si / SiO 2 / C semi-hollow composite structure. Si accounted for Si / SiO 2 The mass percent range of the / C part hollow composite structure is 70%.

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Abstract

A carbon-silicon composite lithium ion battery cathode material and its preparation method are disclosed. Si which is used as an inner core is tightly coated with a SiO2 layer, and a hollow layer is arranged between the SiO2 layer and the outermost C coating layer. The inner core Si accounts for 30-70 wt% of mass of the composite material. The hollow layer is obtained by etching the SiO2 part of the middle layer on the synthesized Si/SiO2/C composite material. When used as a lithium ion battery cathode material in the field of electrochemical application, the material provided by the invention has advantages of high cyclic stability and high coulombic efficiency. There is less environmental pollution during the experimental process. The technology is easy to control and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries with high Coulombic efficiency and long cycle life, specifically a Si / SiO 2 / C part hollow lithium ion battery negative electrode composite material and preparation method thereof. Background technique [0002] Since entering the 21st century, low-carbon has become synonymous with environmental protection, and the contradiction between social development and environmental protection has become increasingly fierce. With the depletion of traditional petroleum energy, people's demand for new energy is becoming stronger and stronger. In view of the pollution of traditional petroleum energy to the environment, people's environmental protection requirements for new energy are getting higher and higher. Lithium is the metal element with the most negative standard electrode potential (-3.04V) and the lightest mass (M=6.941) among all metal elements. Therefore, lithium batteries have the characteristi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36
CPCY02E60/10
Inventor 梁叔全杨林钰刘军唐莎莎闵杰
Owner CENT SOUTH UNIV
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