Negative electrode active material for electrical equipment and electrical equipment using same

Abstract

[Problem] Provide a proposal that can improve the cycle durability of electric equipment such as lithium-ion secondary batteries. [Solution] A negative electrode active material having a structure in which a silicide containing a transition metal is dispersed in a parent phase mainly composed of amorphous or low-crystallinity silicon is used for an electric device. The phase structure includes a silicon-containing alloy having a predetermined composition, and the diffraction peak intensity B of a transition metal silicide in the range of 2θ=37 to 45° in X-ray diffraction measurement using CuKα1 rays of the silicon-containing alloy The value (B / A) of the ratio (B / A) of the diffraction peak intensity A to the (111) plane of Si in the range of 2θ=24 to 33° is 0.41 or more.

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, for 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 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.

Images