A novel silicon material is provided.

An MSix-containing silicon material contains MSix (M is at least one element selected from the group 3 to 9 elements. 1/3≦x≦3) in a silicon matrix.

A p-type thermoelectric material according to one aspect of the present invention is configured such that at least any one of a Mg site, a Si site, a Sn site and/or a Ge site in a compound composed of magnesium (Mg), silicon (Si), tin (Sn) and germanium (Ge) is substituted with any one or more elements selected from the group consisting of alkali metals of group 1A and gold (Au), silver (Ag), copper (Cu), zinc (Zn), calcium (Ca) and gallium (Ga) of group 1B.

To provide a negative electrode for a secondary battery and a secondary battery having a large energy density and a capacity less likely to reduce even after repeated charging and discharging, and manufacturing methods thereof. The above-described problem is solved by a negative electrode for a secondary battery (3) comprising a negative electrode active material layer (3′) including at least a silicon-based active material and a binder, and a negative electrode current collector (14) having a structural form in which the silicon-based active material has an amorphous region including lithium and island-shaped lithium carbonate is distributed in the amorphous region. This negative electrode for a secondary battery (3) is manufactured by a method including a step of forming a negative electrode active material layer (3′) including a Si-based active material and a binder, and a predoping step of bringing an electrolytic solution (5) containing Li into contact with the negative electrode active material layer (3′), applying pressure, and introducing Li ions by an electrochemical method.

A novel process provides for the preparation of the chlorinated, uncharged substance tetrakis(trichlorosilyl)germane, and for the use thereof.

A novel process provides for the preparation of the chlorinated, uncharged substance tetrakis(trichlorosilyl)germane, and for the use thereof.

The present disclosure provides a thermoelectric conversion material having a composition represented by a chemical formula of Li.sub.2−a+bMg.sub.1−bSi. In this thermoelectric conversion material, either requirement (i) in which 0≤a≤0.0001 and 0.0001≤b≤0.25-a or requirement (ii) in which 0.0001≤a≤0.25 and 0≤b≤0.25-a is satisfied. The thermoelectric conversion material has an Li.sub.8Al.sub.3Si.sub.5 type crystalline structure.

The present disclosure provides a thermoelectric conversion material having a composition represented by a chemical formula of Li.sub.2−a+bMg.sub.1−bSi. In this thermoelectric conversion material, either requirement (i) in which 0≤a≤0.0001 and 0.0001≤b≤0.25-a or requirement (ii) in which 0.0001≤a≤0.25 and 0≤b≤0.25-a is satisfied. The thermoelectric conversion material has an Li.sub.8Al.sub.3Si.sub.5 type crystalline structure.

A mesoporous silicon compound includes a mesoporous silicon phase, a metal silicide phase, and a carbon phase. The metal silicide is embedded in mesoporous silicon particles, the surfaces of which are coated with a carbon layer. A weight ratio of elemental silicon to the metal element is from 2:3 to 900:1. The pores of the mesoporous silicon particles have a size distribution from two nanometers to eighty nanometers.

A mesoporous silicon compound includes a mesoporous silicon phase, a metal silicide phase, and a carbon phase. The metal silicide is embedded in mesoporous silicon particles, the surfaces of which are coated with a carbon layer. A weight ratio of elemental silicon to the metal element is from 2:3 to 900:1. The pores of the mesoporous silicon particles have a size distribution from two nanometers to eighty nanometers.

There is provided a thermoelectric material including a compound which is formed of an element R belonging to alkaline earth metal and lanthanoid, and an element X belonging to any of Group 13 elements, Group 14 elements, and Group 15 elements. The composition ratio of the element R and the element X is selected to obtain the compound having an AlB.sub.2 type structure.