The purpose of the present invention is to provide a thermoelectric conversion element having a film which not only maintains sufficient adhesion even when exposed to a high temperature but also exhibits excellent oxidation resistance and crack resistance. The problem is solved by a thermoelectric conversion element including a thermoelectric conversion component, in which the thermoelectric conversion component contains magnesium silicide and/or manganese silicide and is covered with a film containing Si and Zr.

Provided is a novel production method for producing silicon clathrate II. In the production method for producing silicon clathrate II, in a reaction system in which a Na—Si alloy containing Na and Si and an Na getter agent coexist so as not to be in contact with each other, the Na—Si alloy is heated and Na evaporated from the Na—Si alloy is thus caused to react with the Na getter agent to reduce an amount of Na in the Na—Si alloy.

A method for producing a sulfide solid electrolyte includes: preparing a uniform solution that includes at least elemental lithium (Li), elemental tin (Sn), elemental phosphorus (P), and elemental sulfur (S) in an organic solvent; removing the organic solvent from the uniform solution to obtain a precursor; and heat-treating the precursor to obtain a sulfide solid electrolyte.

An electrochemical cell is provided herein as well as methods for preparing electrochemical cells. The electrochemical cell includes a negative electrode and a positive electrode. The negative electrode includes a prelithiated electroactive material including a lithium silicide. Lithium is present in the prelithiated electroactive material in an amount corresponding to greater than or equal to about 10% of a state of charge of the negative electrode. The electrochemical cell has a negative electrode capacity to positive electrode capacity for lithium (N/P) ratio of greater than or equal to about 1, and the electrochemical cell is capable of operating at an operating voltage of less than or equal to about 5 volts.

A thermoelectric conversion material formed of a sintered body containing magnesium silicide as a main component contains 0.5 mass % or more and 10 mass % or less of aluminum oxide. The aluminum oxide is distributed at a crystal grain boundary of the magnesium silicide.

A new silicon material is provided. A negative electrode active material including an Al- and O-containing silicon material, the Al- and O-containing silicon material being configured such that a mass % of Al (W.sub.Al %) satisfies 0<W.sub.Al<1, and a peak indicating Al—O bond is observed in a range of 1565 to 1570 eV in an X-ray absorption fine structure measurement for a K shell of Al.

A silicide-based alloy material and a device in which the silicide-based alloy material is used are disclosed. The silicide-based alloy material can reduce environmental impact and provide high thermoelectric FIGURE of merit at room temperature. Provided is a silicide-based alloy material comprising, as major components, silver, barium and silicon, wherein atomic ratios of elements that constitute the alloy material are as follows: 9 at %≤Ag/(Ag+Ba+Si)≤27 at %, 20 at %≤Ba/(Ag+Ba+Si)≤53 at %, and 37 at %≤Si/(Ag+Ba+Si)≤65 at %, where Ag represents a content of the silver, Ba represents a content of the barium and Si represents a content of the silicon, and the silicide-based alloy material has an average grain size of less than or equal to 20 μm.

A silicide-based alloy material and a device in which the silicide-based alloy material is used are disclosed. The silicide-based alloy material can reduce environmental impact and provide high thermoelectric FIGURE of merit at room temperature. Provided is a silicide-based alloy material comprising, as major components, silver, barium and silicon, wherein atomic ratios of elements that constitute the alloy material are as follows: 9 at %≤Ag/(Ag+Ba+Si)≤27 at %, 20 at %≤Ba/(Ag+Ba+Si)≤53 at %, and 37 at %≤Si/(Ag+Ba+Si)≤65 at %, where Ag represents a content of the silver, Ba represents a content of the barium and Si represents a content of the silicon, and the silicide-based alloy material has an average grain size of less than or equal to 20 μm.

A semiconductor sintered body comprising a polycrystalline body, wherein the polycrystalline body comprises silicon or a silicon alloy, and the average grain size of the crystal grains constituting the polycrystalline body is 1 μm or less, and the electrical conductivity is 10,000 S/m or higher.

A semiconductor sintered body comprising a polycrystalline body, wherein the polycrystalline body comprises silicon or a silicon alloy, and the average grain size of the crystal grains constituting the polycrystalline body is 1 μm or less, and the electrical conductivity is 10,000 S/m or higher.