Negative electrode active material for lithium-ion secondary cell

A negative electrode active material, secondary battery technology, used in secondary batteries, battery electrodes, lithium batteries, etc., can solve the problems of rising internal resistance, low conductivity, particle breakage, etc., to suppress disintegration, improve initial capacity, The effect of reducing resistance

Inactive Publication Date: 2016-08-24
SHOWA DENKO KK +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, particles containing Si and Sn originally have low electrical conductivity, and the volume change is large with the intercalation and deintercalation of lithium ions, so the particles are broken and the conductive path is cut off, resulting in an increase in internal resistance

Method used

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Embodiment 1

[0185] In such a way that the mass ratio of the carbonaceous carbon material (C) to the silicon-containing particles (b2) becomes 1 / 1, the silicon-containing particles (b2) and the carbon precursor (c) are used in a fiber mixer ( MX-X57) Mix for 1 minute. The mixture was placed on an alumina wafer boat, and heated to 250°C at a nitrogen flow rate of 300 ml / min and a temperature increase rate of 10°C / min in a horizontal calcination furnace for heat treatment. The heat-treated product was crushed with a fiber mixer in a nitrogen atmosphere for 1 minute to obtain a carbon precursor covering silicon-containing particles.

[0186] Next, the carbon precursor covering the silicon-containing particles and the carbon nanotubes (b1) were added to ethanol so that the mass ratio of the silicon-containing particles (b2) to the carbon nanotubes (b1) became 1 / 0.3. The homogenizer (UH-50 manufactured by SMT) was used for 60 minutes of dispersion and compounding treatment. The processed materia...

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Abstract

A negative electrode active material for a lithium-ion secondary cell, comprising: (A) a flaked graphitic carbon material in which the IG / ID(G value) is 5.2-100 and the aspect ratio and the area of the optical structure satisfy the relationships 1.5<=AOP<=6 and 0.2*D50<=(SOP*AOP)1 / 2<2*D50 for a 50% diameter D50[mu]m; a composite material (B) obtained by dispersing silicon-containing particles (b2) having an oxygen content of 1-18% by mass and a surface layer comprising SiOx (0<x<=2) in an assembly of carbon nanotubes (b1) having an aspect ratio of 100-1000, at least 90% of the silicon-containing particles (b2) (expressed in terms of quantity) having a primary particle diameter of 200 nm or less; and a carbonaceous carbon material (C) covering at least some of the surface of the silicon-containing particles (b2).

Description

Technical field [0001] The present invention relates to a negative electrode active material for lithium ion secondary batteries. In more detail, the present invention relates to a negative electrode active material for a lithium ion secondary battery with high initial capacity and high capacity retention rate. Background technique [0002] The lithium ion secondary battery is used as a power source for electronic equipment and the like. As a negative electrode material of a lithium ion secondary battery, graphite is generally used. The theoretical capacity of graphite is 372mAh / g. The theoretical capacity of Si and Sn is higher than that of graphite. Therefore, if Si and Sn can be used as negative electrode materials, a high-capacity lithium ion secondary battery can be provided. However, particles containing Si and Sn are inherently low in conductivity, and due to the large changes in volume accompanying the intercalation and deintercalation of lithium ions, the particles ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/587H01M4/36H01M4/38H01M4/48H01M4/62
CPCH01M4/0471H01M4/133H01M4/1393H01M4/364H01M4/366H01M4/386H01M4/587H01M4/62H01M4/625H01M10/052Y02E60/10H01M10/0525
Inventor 宫本大辅
Owner SHOWA DENKO KK
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