Negative electrode active material for electric device and electric device using same

Abstract

The purpose of the present invention is to provide a negative electrode active material that is for an electric device such as a lithium ion secondary battery and that has high cycle durability. The negative electrode active material for an electric device contains an alloy that is represented by chemical formula (1) (in chemical formula (1), M is at least one metal selected from the group consisting of Ti, Zn, C, and combinations thereof, A is unavoidable impurities, x, y, z, and a represent mass percent values, and on this occasion, 0<x<100, 0<y<100, 0<z<100, 0<=a<=0.5, and x+y+z+a=100). The half value width of the diffraction peak of the (111) plane of Si in a range in which 2[theta]=24-33 degree according to X-ray diffraction measurement using the CuK[alpha] line of the alloy is 0.7 degree or higher.

Description

technical field [0001] The present invention relates to a negative electrode active material for electric equipment, and an electric equipment using the negative electrode active material. The negative electrode active material for electrical equipment of the present invention and the electrical equipment using it can be used, for example, as secondary batteries, capacitors, etc., as power sources for driving engines of vehicles such as electric vehicles, fuel cell vehicles, and hybrid electric vehicles, and auxiliary power supplies. power supply. Background technique [0002] In recent years, in order to cope with air pollution and global warming, the reduction of the amount of carbon dioxide has been strongly desired. In the automotive industry, the reduction of carbon dioxide emissions due to the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV) is expected, and electrical equipment such as secondary batteries for driving engines is the key to gra...

AI Technical Summary

Problems solved by technology

However, in carbon / graphite-based negative electrode materials, charge and discharge are performed by the storage / release of lithium ions into graphite crystals, so there is a disadvantage that LiC, which is the compound with the largest lithium introduction, cannot be obtained. 6 The obtained charge and discharge capacity has a theoretical capacity of 372mAh / g or more

[0008] However, in lithium-ion secondary batteries that use 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 absorbing Li ions is about 1.2 times for graphite materials, while for Si materials, a large volume change will be caused by the transition from amorphous state to crystalline state when Si and Li are alloyed ( 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, capacity and cycle durability are in a trade-off relationship, and there is a problem that it is difficult to improve cycle durability while exhibiting high capacity.

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