SiCO-Li composite, making method, and non-aqueous electrolyte secondary cell negative electrode material

A technology of composite materials and mixtures, applied in the direction of battery electrodes, negative electrodes, active material electrodes, etc., can solve the problems of inability to form carbon coating, insufficient conductivity, insufficient use of secondary batteries, etc., and achieve satisfactory cycle performance and unique discharge Features, Effects of Satisfactory Initial Efficiency

Inactive Publication Date: 2007-10-03
SHIN ETSU CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Regarding the technique of imparting electrical conductivity to negative electrode materials, JP-A2000-243396 has the disadvantage that solid-to-solid fusion cannot form a uniform carbon coating, resulting in insufficient electrical conductivity
In the method of JP-A2000-243396 which can form a uniform carbon coating, silicon-based negative electrode materials experience excessive expansion and contraction once lithium ions are adsorbed and desorbed, which means impractical operation and loss of cycles performance
Therefore, it is necessary to limit the charge
In JP-A 2002-042806, despite the obvious improvement in cycle performance, when repeated charge / discharge cycles, due to silicon crystallite precipitation, insufficient structure of carbon coating and insufficient fusion of carbon coating to the substrate, Capacity drops gradually and suddenly after a certain number of charge / discharge cycles
Therefore, this method is not sufficient for use in secondary batteries

Method used

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  • SiCO-Li composite, making method, and non-aqueous electrolyte secondary cell negative electrode material
  • SiCO-Li composite, making method, and non-aqueous electrolyte secondary cell negative electrode material
  • SiCO-Li composite, making method, and non-aqueous electrolyte secondary cell negative electrode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0112] To 120 g of tetramethyltetravinylcyclotetrasiloxane (LS-8670, Shin-Etsu Chemical Co., Ltd.) and 80 g of methylhydrogensiloxane (KF-99, Shin-Etsu Chemical Co., Ltd.) To the curable silicone mixture was added 0.1 g of chloroplatinic acid catalyst (1% solution in chloroplatinic acid). The mixture was mixed thoroughly and pre-cured at 60°C for 1 day. The pre-cured mixture in the form of pellets was placed in a glass container and further placed in an atmosphere-controlled, temperature-programmed muffle furnace where the pre-cured mixture was heated at 200 °C for 2 hours in a nitrogen atmosphere until it is fully cured. The solidified product was pulverized and ground to an average particle size of 10 micrometers in a ball mill using hexane as a dispersion medium. Then the powder was placed in a capped alumina container, and fired at 1000° C. for 3 hours in a nitrogen atmosphere in a muffle furnace with controlled atmosphere and temperature program. After cooling, the cal...

Embodiment 2

[0121] Siloxane powder X-52-1621 (Shin-Etsu Chemical Co., Ltd.) (it has the general formula: (CH 3 SiO 3 / 2 ) n A spherical, trifunctional, highly cross-linked methylsiloxane polymer with an average particle size of about 10 microns) was placed in a covered alumina container. The container was placed in an atmosphere-controlled, temperature-programmed muffle furnace, where the powder was calcined at 1000° C. for 3 hours in a nitrogen atmosphere. After cooling, the calcined product was pulverized on a masscolloider with a clearance of 20 microns to obtain Si-C-O composite powder with an average particle size of about 10 microns.

[0122] In a glove box, under an argon blanket, a portion (17.0 g) of the Si-C-O composite powder was weighed and placed into a glass vial with an internal volume of about 50 ml. To this vial was added 3.0 g of stabilized lithium powder SLMP (FMC Corp.), closed with the cap and shaken manually for mixing. The mixture was transferred to a 500 ml stai...

Embodiment 3

[0126] 120 g of tetramethyltetravinylcyclotetrasiloxane (LS-8670, Shin-Etsu Chemical Co., Ltd.), 80 g of methylhydrogensiloxane, were added to 50 g of naturally occurring flake graphite with an average particle size of 6 μm. (KF-99, Shin-Etsu Chemical Co., Ltd.) and 0.5 g of chloroplatinic acid catalyst (1% chloroplatinic acid solution) in a curable silicone mixture. A further 100 ml of hexane was added. The mixture in patty form was mixed thoroughly and then heated at 60°C to remove solvent and pre-cure. The mixture was cured at 200°C for 1 hour in air.

[0127] The solidified mixture in the form of agglomerates was pulverized and then ground to an average particle size of 15 micrometers in a ball mill using hexane as a dispersion medium. After removing the solvent, the powder was placed in a covered alumina container and calcined at 1000° C. for 3 hours in an atmosphere-controlled, temperature-programmed muffle furnace in a nitrogen atmosphere. After cooling, the calcined...

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Abstract

A SiCO-Li composite is prepared by causing a reactive silane and / or siloxane having crosslinkable groups to crosslink, sintering the crosslinked product into an inorganic Si-C-O composite, and doping the Si-C-O composite with lithium. When the SiCO-Li composite is used as a negative electrode, a lithium ion secondary cell exhibits good cycle performance, unique discharge characteristics and improved initial efficiency.

Description

technical field [0001] The present invention relates to a SiCO-Li composite material usable as a negative electrode material for a nonaqueous electrolyte secondary battery; a preparation method thereof; and a nonaqueous electrolyte secondary battery negative electrode material comprising the composite material. Background technique [0002] With the recent extraordinary development of portable electronic equipment, communication equipment, and the like, secondary batteries with high energy density are strongly required from the viewpoints of economy and size and weight reduction. A kind of prior art method of increasing secondary battery capacity is to use oxide as negative electrode material, for example, the oxide of V, Si, B, Zr or Sn etc. or their composite oxide (referring to JP-A5-174818 and JP-A6-060867 corresponding to U.S. Patent 5,478,671), metal oxides (JP-A10-294112), silicon oxide (Japanese Patent No, 2997741 corresponding to U.S. Patent 5,935,711), and Si 2 N ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/04H01M4/02H01M4/131H01M4/136H01M4/1391H01M4/48H01M4/485
CPCH01M4/1391H01M4/0471H01M4/131H01M4/136H01M4/485H01M2004/027Y02E60/122Y02E60/10C01B32/00C01B33/00C01D15/00H01M4/48
Inventor 荒又干夫渡边浩一朗宫脇悟樫田周福冈宏文
Owner SHIN ETSU CHEM CO LTD
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