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Negative electrode for non-aqueous electrolyte secondary battery, material for non-aqueous electrolyte secondary battery, method of preparing material, and lithium-ion secondary battery

A non-aqueous electrolyte and secondary battery technology, applied in secondary batteries, battery electrodes, batteries, etc., can solve the problems of inability to form a uniform carbon film, decrease in cycle performance, and large irreversible capacity, and achieve excellent cycle stability. Effects of small variation in efficiency and good cycle characteristics

Inactive Publication Date: 2016-05-25
SHIN ETSU CHEM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, using the above-mentioned conventional methods, although the charge-discharge capacity has been improved and the energy density has been improved, the cycle performance is not sufficient, or the characteristics of market demand cannot be fully met, and it may not be able to meet the requirements, and it is desired to further increase the energy density.
[0004] Especially in Patent Document 4, silicon oxide is used as the negative electrode active material of the lithium-ion secondary battery. Although a high-capacity electrode is obtained, according to the inventor's understanding, the cycle performance has not reached due to the large irreversible capacity during the initial charge and discharge. Practical level, therefore, has room for improvement
[0005] In addition, regarding the technique of making the negative electrode active material conductive, Patent Document 6 has the problem that a uniform carbon film (carbon film) cannot be formed due to solid-solid welding, and the conductivity is insufficient.
In addition, in the method of Patent Document 7, although a uniform carbon film can be formed, since Si is used as the negative electrode active material, the expansion and contraction during the adsorption or desorption of lithium ions are too large, resulting in impracticality, Cycling is reduced, so in order to prevent this result, a limit must be placed on the amount charged
In the method of Patent Document 8, although it is confirmed that the cycle performance is improved, due to the precipitation of fine silicon crystals, the carbon-covered structure, and the insufficient fusion with the substrate, the capacity decreases after many charge-discharge cycles. Decrease slowly, and after a certain number of times, there will be a sharp decrease, which is not enough to be used as a secondary battery

Method used

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  • Negative electrode for non-aqueous electrolyte secondary battery, material for non-aqueous electrolyte secondary battery, method of preparing material, and lithium-ion secondary battery
  • Negative electrode for non-aqueous electrolyte secondary battery, material for non-aqueous electrolyte secondary battery, method of preparing material, and lithium-ion secondary battery
  • Negative electrode for non-aqueous electrolyte secondary battery, material for non-aqueous electrolyte secondary battery, method of preparing material, and lithium-ion secondary battery

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preparation example Construction

[0113] As the production method of the negative electrode (molded body), for example, the following methods can be cited. In the negative electrode material for the above-mentioned non-aqueous electrolyte secondary battery, other additives such as conductive agents and binders added as required, solvents such as N-methylpyrrolidone or water are added, mixed into a gel-like mixture, and the The mixture is coated on the current collector sheet. At this time, as the current collector, if it is a material generally used as a negative electrode current collector, such as copper foil and nickel foil, it can be used without limitation in particular thickness and surface treatment. Furthermore, the molding method for molding the mixture into a sheet shape is not particularly limited, and known methods can be used.

[0114]

[0115] The lithium ion secondary battery of the present invention includes the negative electrode of the present invention described above. Known materials su...

Embodiment 1 to Embodiment 4

[0145] (Example 1 to Example 4, Comparative Example 1, Comparative Example 2)

[0146] use as figure 1 Shown rotary kiln, the mass W ( kg / h), the inner diameter T (m) of the furnace core tube is controlled, and a carbon film is formed on the particle surface of the silicon-based negative electrode active material. At this time, the disproportionation of the particles of the silicon-based active material also proceeds simultaneously. At this time, the furnace length L of the furnace tube was set at 8.5 m, and the temperature inside the furnace tube was set at 950°C. In addition, the furnace core tube was inclined by 1 degree relative to the horizontal plane, methane gas was used as the hydrocarbon gas, and argon was used as the inert gas. The introduction amount of these gases is properly adjusted, so that the amount of the carbon film formed on the surface of the particles of the silicon-based negative electrode active material of the non-aqueous electrolyte secondary batte...

Embodiment 5 to Embodiment 8、 comparative example 3

[0167] (Example 5 to Example 8, Comparative Example 3, Comparative Example 4)

[0168] Basically, the carbon film is formed on the particle surface of the silicon-based negative electrode active material in the same manner as in the above-mentioned embodiment 1, but as shown in the following table 2, the number of revolutions R (rpm) of the furnace core tube is changed, and the furnace core is dropped into The mass W (kg / h) per unit time of the particles of the silicon-based negative electrode active material in the tube, and the inner diameter T (m) of the furnace core tube. In addition, the furnace length L of the furnace tube at this time was 3 m, and the temperature inside the furnace tube was 1040°C.

[0169] Further, the particles of the silicon-based negative electrode active material use SiO x (x=1.01) and average particle size (D 50 ) is silicon oxide of 4 μm. In addition, the average particle diameter mentioned here is the volume average particle diameter in the p...

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Abstract

The invention provides a manufacturing method which can not only efficiently produce a negative electrode material that is coated with a uniform carbon coating and crystallinity, but also mass-produce negative electrode materials having a high capacity and a high cycle performance. Accordingly, the present invention is a method of producing a negative electrode material for a non-aqueous electrolyte secondary battery, including: preparing silicon-based negative electrode active material particles; and coating each of the prepared particles with a conductive carbon coating by using a rotary kiln while controlling the rotary kiln such that the following relationships (1) and (2) hold true: W / (376.8RT2)<=1.0 (1); and (TR2 / 0.353)<=3.0 (2), where R is a rotation rate (rpm) of the furnace tube of the rotary kiln, W is a mass (kg / h) of the particles that are put in the furnace tube per hour, and T is an inner diameter (m) of the furnace tube.

Description

technical field [0001] The present invention relates to a method for manufacturing a negative electrode material for a nonaqueous electrolyte secondary battery, a negative electrode material for a nonaqueous electrolyte secondary battery manufactured by the method, and a negative electrode for a nonaqueous electrolyte secondary battery containing the negative electrode material and lithium-ion secondary batteries. Background technique [0002] In recent years, with the remarkable development of portable electronic equipment, communication equipment, etc., a secondary battery with high energy density has been strongly desired from the viewpoint of economy, miniaturization and weight reduction of the equipment. In the past, as a high-capacity scheme of such a secondary battery, the following method is known, for example, using oxides such as V, Si, B, Zr, Sn and their composite oxides in the negative electrode material (refer to, for example, Patent Document 1, Patent Documen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/131H01M4/1391H01M4/36H01M4/48H01M4/62H01M10/0525
CPCH01M4/131H01M4/1391H01M4/366H01M4/48H01M4/625H01M10/0525H01M4/134H01M4/587H01M4/386H01M2220/30Y02E60/10
Inventor 古屋昌浩高桥广太吉川博树
Owner SHIN ETSU CHEM IND CO LTD
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