Negative electrode for non-aqueous electrolyte secondary battery, producing method therefor, and non-aqueous electrolyte secondary battery

A non-aqueous electrolyte and secondary battery technology, applied in the direction of secondary batteries, battery electrodes, active material electrodes, etc., can solve the problems of reduced cycle characteristics and storage characteristics, side effects of positive active materials, and difficulty in maintaining adhesion functions, etc., to achieve Effects of high energy density, excellent adhesion and heat resistance, and excellent electron conductivity

Active Publication Date: 2007-01-24
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] However, the above-mentioned organic solvent-soluble binders are dissolved in the organic electrolyte of the non-aqueous electrolyte secondary battery, and it is difficult to maintain the binding function, resulting in a decrease in cycle characteristics and storage characteristics
In addition, without high-temperature heat treatment, water generated in dehydration condensation by imidization is retained and can cause adverse effects on positive active materials

Method used

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  • Negative electrode for non-aqueous electrolyte secondary battery, producing method therefor, and non-aqueous electrolyte secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] (1) Preparation of negative electrode active material

[0068] Ti powder (manufactured by Kojundo Chemical Lab. Co., Ltd., 99.99% purity, particle size below 20 μm) and Si powder (manufactured by Kanto Chemical Co., Inc., 99.99% purity, particle size less than 20 μm), so that the proportion of the Si phase, that is, the phase A in the negative electrode active material particle, was 30% by weight.

[0069] The mixed powder was placed in a vibratory mill container, and stainless steel balls (2 cm in diameter) were further placed so that the balls occupied 70% by volume of the container capacity. After evacuating the inside of the container, the inside of the container was replaced with Ar (manufactured by Nippon Sanso Corporation, 99.999% purity) until the inside pressure of the container became 1 atm. Then, mechanical alloying was performed for 40 hours while applying vibration of 60 Hz to obtain a Ti—Si alloy.

[0070] As a result of performing X-ray diffraction meas...

Embodiment 2-5

[0106] In these examples, in the case where polyimide and polyacrylic acid were used for the negative electrode binder, the heating temperature of negative electrode pellets containing polyamic acid as a polyimide precursor was examined.

[0107] Coin cells were prepared in the same manner as in Example 1 except that the heating temperature of the negative electrode pellets was changed to the temperatures shown in Table 2, and then evaluated. Together with the results of Example 1, the evaluation results are shown in Table 2.

[0108] Negative electrode pellets

heating temperature

(℃)

Polyacrylic acid

imidization

Rate(%)

initial capacity

(mAh)

Low temperature capacity

retention rate

(%)

Cycle capacity

retention rate

(%)

Example 2

150

reserve

20

6.5

85

84

Example 3

200

reserve

80

6.5

85

90

Example 1

...

Embodiment 6-10

[0114] In these examples, when polyimide and polyacrylic acid were used as the binder in the preparation of the negative electrode, the contents of the binder materials (polyamic acid and polyacrylic acid) in the negative electrode mixture were examined.

[0115] A button cell was prepared in the same manner as in Example 1, except that in the negative electrode mixture, the content of the binder was variously changed per 100 parts by weight of the negative active material, as shown in Table 3, but the binder material was not changed The mixing ratio of polyamic acid and polyacrylic acid was evaluated.

[0116] Together with the results of Example 1, the evaluation results are shown in Table 3.

[0117] Binder in negative electrode mixture

Material content (parts by weight)

initial capacity

(mAh)

cycle capacity retention

(%)

Example 6

0.2

6.5

86

Example 7

0.5

6.5

93

Example 8

5.0 ...

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Abstract

A negative electrode for a non-aqueous electrolyte secondary battery in the present invention includes an active material including Si, a conductive material, and a binder. The binder is polyimide and polyacrylic acid, and the conductive material is a carbon material.

Description

technical field [0001] The present invention relates to a non-aqueous electrolyte secondary battery, in particular to the improvement of the negative electrode used in the non-aqueous electrolyte secondary battery. Background technique [0002] Nonaqueous electrolyte batteries are small and lightweight, have high energy density, and are used as a main power source for various electronic devices and as a backup power source for memories. Nowadays, with significant advantages of portable electronic devices regarding further miniaturization, higher performance and less maintenance, further high energy density is required in non-aqueous electrolyte batteries. [0003] For the positive electrode active material and the negative electrode active material, many experiments have been conducted because battery characteristics are highly dependent on the characteristics of the positive electrode active material and the negative electrode active material. [0004] For example, Si can ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62C08L79/08C09J133/02C09J179/08H01M4/02H01M4/38H01M4/58H01M10/40H01M4/134H01M4/1395H01M10/0525H01M10/36
CPCY02E60/122H01M4/621H01M4/625H01M4/622H01M10/0525H01M4/1395H01M4/364H01M4/134Y02E60/10
Inventor 植田智博南野哲郎美藤靖彦
Owner PANASONIC CORP
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