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Anode material for lithium secondary battery, manufacturing method of the same, lithium secondary battery anode using the same, and lithium secondary battery

A technology for lithium secondary batteries and negative electrode materials, which is applied in secondary batteries, battery electrodes, non-aqueous electrolyte battery electrodes, etc., and can solve the problems of irreversible capacity increase, capacity retention rate (deterioration of cycle characteristics, increase of reaction surface, etc.) , to achieve the effect of excellent battery characteristics, small irreversible capacity and high plate strength

Active Publication Date: 2007-06-27
MITSUBISHI RAYON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, problems such as increased irreversible capacity, decomposition of the electrolyte caused by the reaction of the anode active material material and the electrolyte during charge or discharge, and capacity retention due to the reaction of the anode active material material and the electrolyte during repeated charge and discharge (cycle characteristics ) worsens, etc.
[0008] However, for conventional polymer materials represented by the technology of Patent Document 1 or Patent Document 2, if a polymer that is easily soluble in an electrolyte is coated on a carbon material, when used as an actual battery, the polymer will The material slowly dissolves and expands in the electrolyte, and the reaction surface gradually increases, so that the irreversible capacity increases
In addition, if the polymer that is poorly soluble in the electrolyte is directly coated on the carbon material, the active surface where Li can enter and exit is reduced, the resistance is increased, and the charge-discharge capacity or cycle performance at high current capacity is significantly reduced.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0130] 2 g of polyvinylidene fluoride (W#1300 manufactured by Kureha Chemical Co., Ltd.) as a polymer material (C-1) was added to 198 g of 1-methyl-2-pyrrolidone and dissolved. In this solution, the specific surface area added as particle (A) (negative electrode active material particle) is 6.4m 2 / g, 200 g of spheroidized natural graphite particles with an average particle diameter of 16 μm, and in a stainless steel container with a volume of 0.75 L, stirred and mixed with a homogeneous disperser for 2 hours. The resulting mixture was charged into a stainless steel cylinder to a packing height of 1.5 cm, and dried at 110° C. for 10 hours in nitrogen. This was sieved to obtain negative electrode active material particles with one layer of polymer material attached. Furthermore, 0.2 g of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd. NM14) as a polymer material (C-2) was added to 199.8 g of pure water heated to 70° C. to dissolve it, and air C...

Embodiment 2

[0132] 2 g of carboxymethylcellulose (BSH6 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as a polymer material (C-1) was added to 198 g of pure water and dissolved. In this solution, 200 g of graphite particles used in Example 1 were added as particles (A) (negative electrode active material particles), and stirred and mixed for 2 hours in a SUS container with a capacity of 0.75 L using a homogeneous disperser . Except for this, in the same procedure as in Example 1, negative electrode active material particles with two layers of polymer materials adhered were obtained. This was used as the negative electrode material of Example 2.

Embodiment 3

[0134] 2 g of polymethyl methacrylate (methyl methacrylate polymer manufactured by Wako Pure Chemical Industries, Ltd.) as a polymer material (C-1) was added to 198 g of acetone and dissolved. In this solution, 200 g of graphite particles used in Example 1 were added as particles (A) (negative electrode active material particles), and stirred and mixed for 2 hours in a SUS container with a capacity of 0.75 L using a homogeneous disperser . Except for this, in the same procedure as in Example 1, negative electrode active material particles with two layers of polymer materials adhered were obtained. This was used as the negative electrode material of Example 3.

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PUM

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Abstract

Disclosed is a negative electrode material which can be produced by a simple process and enables to obtain a lithium secondary battery which is excellent in various battery characteristics, namely a lithium secondary battery having high electrode plate strength, good immersibility, small initial irreversible capacity, excellent charge / discharge characteristics at high current density and high cycle retention rate. Specifically disclosed is a negative electrode material wherein two or more different polymer materials are respectively adhered to different positions of a particle (A) which is selected from the group consisting of carbon material particles, metal particles and metal oxide particles.

Description

technical field [0001] The present invention relates to a negative electrode material for a lithium secondary battery and a manufacturing method thereof, and further relates to a negative electrode for a lithium secondary battery and a lithium secondary battery using the material. Background technique [0002] In recent years, along with miniaturization of electronic equipment, it is desired to increase the capacity of secondary batteries. Therefore, compared with nickel-cadmium batteries and nickel-hydrogen batteries, lithium secondary batteries with higher energy density have attracted people's attention. [0003] At first, metallic lithium was tried as the negative electrode active material of the secondary battery, but it was found that during repeated charging and discharging, dendritic lithium precipitated, penetrated the separator and reached the positive electrode, possibly causing a short circuit. Therefore, the current use of carbon materials as negative electrode...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/02H01M4/38H01M4/48H01M4/58H01M4/62H01M10/40H01M10/0565H01M4/13H01M4/133H01M4/36H01M4/587H01M10/0525H01M10/36
CPCH01M4/587Y02E60/12H01M4/483H01M2004/027H01M4/622H01M4/133H01M4/13H01M4/364H01M4/38H01M4/621H01M4/02H01M10/0525Y02E60/122Y02E60/10H01M10/0565H01M4/36
Inventor 横沟正和佐藤秀治鎌田富行
Owner MITSUBISHI RAYON CO LTD
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