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

Abstract

[Problem] To provide a means for improving the cycle durability of electrical equipment such as lithium-ion secondary batteries. [Solution] Use a negative electrode active material containing a silicon-containing alloy in an electrical device, the silicon-containing alloy having the chemical formula (I): Si x sn y m z A a The composition shown, in the formula, A represents unavoidable impurities, M represents one or more transition metal elements, x, y, z and a represent the value of mass%, at this time, 0<x<100, 0 < y < 100, 0 < z < 100 and 0 ≤ a < 0.5, and x + y + z + a = 100, according to the Fourier transform processing of the lattice image obtained by the transmission electron microscope of the silicon-containing alloy A diffraction pattern is obtained, and in this diffraction pattern, the portion of the diffraction ring that exists within a width of 0.7 to 1.0 when the distance between Si regular tetrahedra is 1.0 is subjected to inverse Fourier transform, and the amorphous When the distance between the Si regular tetrahedrons of the solid region is small, the distance between the Si regular tetrahedrons is 0.39 nm 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 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, it is urgently desired to reduce the amount of carbon dioxide. 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 holds the key to the practical use of these It's in full swing. [...

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 stored is about 1.2 times for graphite materials, and in the case of Si materials, when Si and Li are alloyed, a larger transition occurs from an amorphous state to a crystalline state. Volume change (about 4 times), so there is a problem that the cycle life of the electrode is shortened

In addition, in the case of Si negative electrode active materials, 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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