Conductive silicon compound, its preparation and negative electrode material of non-aqueous electrolyte secondary battery

A composite and conductive silicon technology, applied in secondary batteries, secondary battery components, battery electrodes, etc., can solve problems such as insufficient use of secondary batteries, insufficient carbon coating structure, and reduced cycle performance

Inactive Publication Date: 2004-07-21
SHIN ETSU CHEM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

JP2000-215887A was successful in forming a uniform carbon coating, but due to the absorption and desorption of lithium ions, the silicon-based anode material experienced abnormal expansion and contraction, and the result was not up to practical use requirements
At the same time, cycle performance decreases and charge / discharge capacity must be limited to prevent this decrease
In JP2002-42806A, the improvement in cycle performance is identifiable, but as the charge / discharge cycle is repeated, because of the precipitation of silicon crystallites, insufficient structure of the carbon coating, and insufficient fusion of the carbon coating with the underlying layer , so the capacity decreases gradually and suddenly after a certain number of cycles
Therefore, this negative electrode material is not yet sufficient for use in secondary batteries

Method used

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  • Conductive silicon compound, its preparation and negative electrode material of non-aqueous electrolyte secondary battery
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  • Conductive silicon compound, its preparation and negative electrode material of non-aqueous electrolyte secondary battery

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Embodiment 1

[0060] To illustrate the structure of the conductive silicon composite of the present invention, refer to an exemplary conductive silicon composite made of silicon oxide (SiOx) as a raw material.

[0061] Silicon oxide (SiOx, x=1.02) was ground in a ball mill using hexane as a dispersion medium. The silicon oxide powder thus obtained was put into a rotary kiln-type reactor. In this reactor, the disproportionation of silicon oxide and thermal CVD were carried out simultaneously in a mixed flow of methane-argon gas at 1150°C and the average residence time was about 2 hour. The powder thus obtained was analyzed by solid-state NMR, x-ray diffractometry, TEM microphotography, and Raman spectroscopy (excitation light 532 nm), and the results are shown in FIGS. 1 to 4, respectively. From the solid state of silicon oxide as the raw material and conductive silicon composite as the final product 29 From the results of Si-NMR analysis, it can be seen that on the curve of a conductive silicon...

Embodiment 2

[0067]Using hexane as a dispersion medium, silicon oxide (SiOx, x=1.02) was ground in a ball mill. By filtering the suspension thus prepared in a nitrogen atmosphere and removing the solvent, a powder with an average particle size of about 0.8 μm is obtained. The silicon oxide powder is placed in a rotary furnace-type reactor, in which a methane-argon mixed gas stream is simultaneously subjected to disproportionation and thermal CVD of silicon oxide with an average residence time of approximately 2 hours at 1150°C. The product thus obtained had a carbon content of 16.5%, and the amount of active silicon or zero-valent silicon determined from the amount of hydrogen generated by the reaction with the potassium hydroxide aqueous solution was 26.7%. Analyzed by x-ray diffractometry (Cu-Kα), silicon crystals dispersed in silicon dioxide had a size of approximately 11 nm determined by the Scherrer method from the half-width of the Si(111) diffraction line at 2θ=28.4°. At the end of ther...

Embodiment 3

[0074] In an inert gas (argon) environment, heat block or flake silicon oxide at 1300°C for one hour to disproportionate into silicon and silicon dioxide. The analysis was performed by x-ray diffractometry (Cu-Kα), and the silicon crystals in the product had a size of approximately 55 nm determined by the Scherrer method from the half-width of the Si(111) diffraction line at 2θ=28.4°. The heat-treated silicon-silica composite was then ground in a ball mill using hexane as a dispersion medium. In a nitrogen environment, by filtering the suspension thus obtained and removing the solvent, a powder with an average particle size of approximately 0.8 μm is obtained. The silicon composite powder was placed in a vertical tube furnace (inner diameter ~ 50 mm), and in the furnace, thermal CVD was performed for 3 hours at 1100°C under a mixed gas flow of methane and argon. The conductive silicon composite powder thus obtained is pulverized in an automatic grinding body. The conductive silico...

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Abstract

A conductive silicon composite in which particles having a structure in which crystallites of silicon are dispersed in silicon dioxide are coated on their surfaces with carbon affords satisfactory cycle performance when used as the negative electrode material in a non-aqueous electrolyte secondary cell.

Description

Technical field [0001] The present invention relates to a silicon composite powder that has conductivity and can be used as a negative electrode active material in a lithium ion secondary battery, a method for preparing the powder, and a negative electrode material used in a non-aqueous electrolyte secondary battery. Background technique [0002] With the recent rapid development of portable electronic devices and communication devices, there is a strong demand for secondary batteries with high energy density from the viewpoints of economy, size, and weight reduction. Known prior art attempts to increase the capacity of such secondary batteries include V, Si, B, Zr, Sn, etc. oxides or their composite oxides (JP5-174818A, JP6-60867A corresponding to USP5478671), melt quenching Metal oxide (JP1O-294112A), silicon oxide (corresponding to Japanese Patent No. 2997741 of USP5395711) and Si 2 N 2 O or Ge 2 N 2 O (corresponding to JP11-102705A of USP6066414) was used as the negative elec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09C1/30H01M4/02H01M4/38H01M4/48H01M4/485H01M10/0525H01M10/36
CPCY02E60/12H01M4/38C01P2002/82C01P2006/40C01P2002/60C01P2004/51H01M10/0525H01M4/485C01P2004/61C01P2006/12H01M2004/027Y02E60/122C01P2002/72C01P2004/84C01P2004/80C09C1/30C01P2004/64C01P2004/04H01M2004/021C01P2004/50C01P2002/86C01P2004/62B82Y30/00C01P2006/80H01M4/366H01M4/386H01M4/625Y02E60/10Y10T428/12493Y10T428/12528Y10T428/12611Y10T428/2982Y10T428/2991H01M4/139
Inventor 荒又干夫宫胁悟上野进福冈宏文籾井一磨
Owner SHIN ETSU CHEM IND CO LTD
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