Negative electrode active material for electrical device, and electrical device in which said material is used

Abstract

The invention aims to provide a means with which it is possible to improve cycle durability in an electrical device such as a lithium-ion secondary cell. There is used, in an electrical device, a negative electrode active material comprising an Si-containing alloy having a composition represented by chemical formula (1): SixSnyMzAlwAa (where M is one or more transition metal elements; A is unavoidable impurities; and x, y, z, w, and a represent mass% values , where y, z, and w are respectively 2 <= y <= 10, 25 <= z <= 35, and 0.3 <= w <= 3, and x and a are remainders). The composition containsSi-containing alloy.

Description

technical field [0001] The present invention relates to a negative electrode active material for electric equipment and an electric equipment using the same. The negative electrode active material for electrical equipment of the present invention and electrical equipment using the same are used, for example, as secondary batteries, capacitors, etc., as driving power sources and auxiliary power sources for engines of vehicles such as electric vehicles, fuel cell vehicles, and hybrid electric vehicles. Background technique [0002] In recent years, in order to cope with air pollution and global warming, reduction of the amount of carbon dioxide has been strongly desired. In the automotive industry, the introduction of electric vehicles (EVs) and hybrid electric vehicles (HEVs) is expected to reduce carbon dioxide emissions, and the development of electrical equipment such as secondary batteries for driving engines, which is the key to grasping their practical application, is a...

AI Technical Summary

Problems solved by technology

[0008] However, in a lithium ion secondary battery using a material alloyed with Li for the negative electrode, the expansion and contraction of the negative electrode during charge and discharge are large.

For example, the volume expansion when Li ions are absorbed is approximately 1.2 times for graphite materials. On the other hand, for Si materials, when Si and Li are alloyed, the transition from an amorphous state to a crystalline state occurs. Large volume change (about 4 times), so there is a problem that the cycle life of the electrode is reduced

In addition, in the case of the Si negative electrode active material, there is a trade-off relationship between capacity and cycle durability, and there is a problem that it is difficult to improve cycle durability while exhibiting high capacity.

Images