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Negative electrode for lithium ion secondary battery, process for producing the same, lithium ion secondary battery and process for producing the same

A secondary battery, lithium ion technology, used in secondary batteries, electrode manufacturing, battery electrodes, etc., can solve the problems of reducing electrode performance, electrode current collection performance, etc., and achieve the effect of excellent cycle characteristics

Inactive Publication Date: 2008-01-09
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the current collecting performance of the electrode is reduced, thereby reducing the electrode performance

Method used

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  • Negative electrode for lithium ion secondary battery, process for producing the same, lithium ion secondary battery and process for producing the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] (i) Preparation of negative electrode

[0069] A Ti—Si alloy (Ti: 37% by weight, Si 63% by weight) used as an anode active material was prepared by a mechanical alloying process. Analysis of the resulting alloy by the electron diffraction method using a transmission electron microscope confirmed that the alloy contained TiSi 2 And Si two-phase.

[0070] Negative electrode material mixture slurry was prepared by thoroughly mixing the negative electrode material mixture containing Ti—Si alloy powder (average particle size: 10 μm), binder powder and conductive agent with water as the liquid dispersion medium. Acetylene black was used as a conductive agent. Resin materials listed in Table 1 were used as binders.

[0071] Here, the content of the acrylic acid unit contained in the ethylene-acrylic acid copolymer, the content of the methacrylic acid unit contained in the ethylene-methacrylic acid copolymer, the content of the acrylic acid unit contained in the styrene-acry...

Embodiment 2

[0092] Except changing the content of acrylic acid unit and methacrylic acid unit in ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer respectively as shown in table 2 (85mol%, 82mol%, 80mol%, 60mol%, 40mol%, 10mol%) %, 4mol%, 3mol% or 2mol%), batteries B1-B9 and batteries C1-C9 were prepared in the same manner as batteries A2 and A3 of Example 1. The resulting battery was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0093] Table 2

[0094] Binder: Ethylene-acrylic acid copolymer

[0095] More preferred results are obtained when the content of acrylic acid units in the ethylene-acrylic acid copolymer is in the range of 80 mol% to 4 mol%. Similarly, more preferable results are obtained when the content of methacrylic acid units in the ethylene-methacrylic acid copolymer is in the range of 80 mol% to 4 mol%. It seems that the flexibility of the adhesive is relatively lowered when the cont...

Embodiment 3

[0097] In addition to changing the amount of ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer occupying the negative electrode material mixture (ie the total amount of Ti-Si alloy, binder and conductive agent) as shown in Table 3 (30% by weight, 25% by weight), % by weight, 20% by weight, 1% by weight, 0.5% by weight or 0.3% by weight), batteries D1-D6 and batteries E1-E6 were prepared according to the same method as batteries A2 and A3 of Example 1. The amounts of Ti-Si alloy and conductive agent are the same as those in Example 1. The resulting battery was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0098] table 3

[0099] Binder: Ethylene-acrylic acid copolymer

[0100]More preferable results are obtained when the content of the ethylene-acrylic acid copolymer and the ethylene-methacrylic acid copolymer contained in the negative electrode material mixture is in the range of 0.5% ...

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Abstract

A negative electrode for lithium ion secondary battery, comprising a negative electrode mixture containing a powdery active material capable of reversible lithium occlusion and release and a binding agent, wherein the active material contains at least one element selected from the group consisting of Si and Sn, and wherein the binding agent contains at least one member selected from the group consisting of an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer.

Description

technical field [0001] The present invention relates to lithium ion secondary batteries, and in particular to their negative electrodes. Background technique [0002] Lithium ion secondary batteries have high voltage and high energy density. Recently, lithium ion secondary batteries have been used as the main power source of many devices including, for example, mobile communication devices and portable electronic devices. Along with the reduction in size and improvement in performance of these devices, improvements in lithium-ion secondary battery performance are also required, and many studies are underway. [0003] Various materials have been proposed and studied as positive and negative active materials for lithium ion secondary batteries. For negative electrode active materials, such as carbon materials and aluminum alloys have been put into practical use. Among them, carbon materials exhibit the highest performance and are being widely used. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/02H01M4/04H01M4/38H01M4/48H01M4/58H01M10/40H01M4/131H01M4/134H01M4/1395H01M4/485H01M4/52H01M4/525H01M10/0525H01M10/058H01M10/36
CPCH01M4/622Y02T10/7011H01M4/02H01M10/0525H01M4/525H01M4/485H01M2004/027Y02E60/122H01M4/621H01M4/1395H01M10/058H01M4/134H01M4/131Y10T29/4911Y02E60/10Y02P70/50H01M4/62H01M4/38H01M4/139Y02T10/70
Inventor 长谷川正树美藤靖彦
Owner PANASONIC CORP
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