Negative-electrode active material and method for producing same

A negative electrode active material and simple substance technology, applied in the field of negative electrode active material and its preparation, can solve the problems of electrolyte consumption and battery cycle characteristics degradation, and achieve the effects of high initial efficiency, stable slurry, and good initial charge and discharge characteristics

Pending Publication Date: 2021-07-23
SHIN ETSU CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this time, since the decomposition reaction of the electrolyte solution occurs on the newly formed surface, and a film of decomposition products of the electrolyte solution is formed on the newly formed surface, the electrolyte solution is consumed.
Therefore, the cycle characteristics of the battery tend to decrease

Method used

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  • Negative-electrode active material and method for producing same
  • Negative-electrode active material and method for producing same
  • Negative-electrode active material and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-1

[0193] First, a negative electrode active material was prepared in the following manner. The raw material mixed with metal silicon and silicon dioxide is introduced into the reaction furnace, and the material formed by vaporizing it in an atmosphere with a vacuum degree of 10Pa is deposited on the adsorption plate and cooled sufficiently, then the deposit is taken out and pulverized by a ball mill . SiO of silicon compound particles obtained in this way x has an x-value of 1.0. Next, the particle diameter of the silicon compound particles is adjusted by classification. Then, by performing pyrolytic CVD, the carbon material is coated on the surface of the silicon compound particles.

[0194] Next, the silicon compound particles are modified by absorbing lithium by a redox method. Then, heating is performed in the range of 450°C to 750°C to perform modification.

[0195] The particle size of the obtained negative electrode active material particles and the thickness of the ...

Embodiment 1-2、1-3

[0205] The negative electrode active material was prepared in the same manner as in Example 1-1 except that the heat treatment temperature and treatment atmosphere conditions were changed. In addition, each measurement was performed in the same manner as in Example 1-1.

Embodiment 2-1~ Embodiment 2-4

[0217] In addition, the preparation of the negative electrode active material was performed in the same manner as in Example 1-1, except that the crystallinity of silicon was controlled by changing the bath temperature at the time of lithium doping and the subsequent heat treatment conditions. In addition, each measurement was performed in the same manner as in Example 1-1.

[0218] Table 2 shows the evaluation results of Example 2-1 to Example 2-4. In addition, the Raman spectra obtained by the negative electrode active materials of Examples 1-3, 2-1 to 2-3 are shown in image 3 , the Raman spectrum obtained by the negative electrode active material of Example 2-4 is shown in Figure 4 .

[0219] [Table 2]

[0220]

[0221] As shown in Table 2, the higher the crystallinity of silicon, the faster gas is generated. Considering the manufacturing process of the lithium ion secondary battery, the peak of crystalline silicon is less than 1.1A≧B (Example 2-3), which enables m...

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Abstract

The present invention is a negative-electrode active material comprising negative-electrode active material particles, the negative-electrode active material being characterized in that the negative-electrode active material particles comprise silicon compound particles each containing an oxygen-containing silicon compound, each of the silicon compound particles contains at least one component selected from Li2SiO3 and Li2Si2O5, and each of the silicon compound particles has a peak P attributed to a Li silicate at a position around 1847 eV and also has a peak Q that is gentler than the peak P at a position around 1851 to 1852 eV in an Si K-edge spectrum obtained from an XANES spectrum. It is possible to provide a negative-electrode active material which enables the increase in a battery capacity associated with the improvement in initial efficiency while stabilizing a slurry when used as a negative-electrode active material for a secondary battery.

Description

technical field [0001] The invention relates to a negative electrode active material and a preparation method thereof. Background technique [0002] In recent years, small electronic devices represented by mobile terminals and the like have been widely used, and further miniaturization, weight reduction, and long life are strongly demanded. In response to such market demands, the development of a particularly small and lightweight secondary battery capable of achieving high energy density has been advanced. The application of this secondary battery is not limited to small electronic devices, and its application to large electronic devices represented by automobiles and power storage systems represented by houses and the like is also being studied. [0003] Among them, lithium-ion secondary batteries are expected to be easy to miniaturize and increase in capacity, and can obtain higher energy density than lead batteries and nickel-cadmium batteries. [0004] The above-menti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/32H01M4/36H01M4/38H01M4/485H01M4/58
CPCC01B33/32H01M4/485Y02E60/10H01M4/366H01M4/625C01P2004/60H01M4/483H01M4/5825H01M4/62C01P2002/70C01P2002/82C01P2002/86H01M2004/021H01M2004/027
Inventor 广濑贵一酒井玲子大泽祐介高桥广太松野拓史
Owner SHIN ETSU CHEM CO LTD
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