A silicon-containing structure including: a silicon composite including a porous silicon secondary particle and a first carbon flake on a surface of the porous silicon secondary particle; a carbonaceous coating layer on the porous silicon composite, the carbonaceous coating layer comprising a first amorphous carbon; and the silicon composite comprises a second amorphous carbon and has a density that is equal to or less than a density of the carbonaceous coating layer, wherein the porous silicon secondary particle includes an aggregate of silicon composite primary particles, each including silicon, a silicon suboxide on a surface of the silicon, and a second carbon flake on a surface of the silicon suboxide.

A thermoelectric element material according to the present invention includes a quantum dot portion including a large number of quantum dots. The quantum dot portion includes carriers therein, the carriers serving to carry an electric current. Of the large number of quantum dots, adjacent quantum dots are separate from each other and are close to each other to an extent allowing the carriers to move between the quantum dots.

An example power generation system includes two capacitors and an electric load. A first capacitor includes a dielectric material that is configured to transition from a ferroelectric phase to a paraelectric or antiferroelectric phase when heated above a first transition temperature, and to transition from the paraelectric or antiferroelectric phase to the ferroelectric phase when cooled below a second transition temperature. A second capacitor is electrically coupled in parallel to the first capacitor. The electric load is electrically coupled to the first capacitor and the second capacitor. The system is configured to cyclically cool the dielectric material below the second transition temperature to draw a charge from the second capacitor to the first capacitors through the electric load, and heat the dielectric material beyond the first transition temperature to draw a charge from the first capacitor to the second capacitors through the electric load.

An apparatus and method perform supersonic cold-spraying to deposit N and P-type thermoelectric semiconductor, and other polycrystalline materials on other materials of varying complex shapes. The process developed has been demonstrated for bismuth and antimony telluride formulations as well as Tetrahedrite type copper sulfosalt materials. Both thick and thin layer thermoelectric semiconductor material is deposited over small or large areas to flat and highly complex shaped surfaces and will therefore help create a far greater application set for thermoelectric generator (TEG) systems. This process when combined with other manufacturing processes allows the total additive manufacturing of complete thermoelectric generator based waste heat recovery systems. The processes also directly apply to both thermoelectric cooler (TEC) systems, thermopile devices, and other polycrystalline functional material applications.

A thermoelectric conversion material consists of a non-doped sintered body of a magnesium-based compound, in which an electric resistance value is 1.010.sup.4 .Math.m or less. The magnesium-based compound is preferably one or more selected from a MgSi-based compound, a MgSn-based compound, a MgSiSn-based compound, and a MgSiGe-based compound.

In some embodiments, thermoelectric apparatus and various applications of thermoelectric apparatus are described herein. In some embodiments, a thermoelectric apparatus described herein comprises at least one p-type layer coupled to at least one n-type layer to provide a pn junction, and an insulating layer at least partially disposed between the p-type layer and the n-type layer, the p-type layer comprising a plurality of carbon nanoparticles and the n-type layer comprising a plurality of n-doped carbon nanoparticles.

Example systems, apparatuses, and methods are disclosed sensing a flow of fluid using a thermopile-based flow sensing device. An example apparatus includes a flow sensing device comprising a heating structure having a centerline. The flow sensing device may further comprise a thermopile. At least a portion of the thermopile may be disposed over the heating structure. The thermopile may comprise a first thermocouple having a first thermocouple junction disposed upstream of the centerline of the heating structure. The thermopile may further comprise a second thermocouple having a second thermocouple junction disposed downstream of the centerline of the heating structure.

A thermoelectric module includes: unit thermoelectric materials including N-type thermoelectric materials and P-type thermoelectric materials and arranged on one surface of a first substrate; first electrodes each electrically connected to one end of a respective one of the N-type thermoelectric materials or to one end of a respective one of the P-type thermoelectric materials; second electrodes each disposed to be spaced apart from the other end of the respective one of the N-type thermoelectric materials and the other end of the respective one of the P-type thermoelectric materials by a predetermined gap; and a second substrate supporting the second electrodes, in which each of the second electrodes is electrically connected to the second end of the respective one of the N-type thermoelectric materials and the second end of the respective one of the P-type thermoelectric materials when a pressing force is applied to the second substrate.

Disclosed are methods for the manufacture of n-type and p-type filled skutterudite thermoelectric legs of an electrical contact. A first material of CoSi.sub.2 and a dopant are ball-milled to form a first powder which is thermo-mechanically processed with a second powder of n-type skutterudite to form a n-type skutterudite layer disposed between a first layer and a third layer of the doped-CoSi.sub.2. In addition, a plurality of components such as iron, and nickel, and at least one of cobalt or chromium are ball-milled form a first powder that is thermo-mechanically processed with a p-type skutterudite layer to form a p-type skutterudite layer second layer disposed between a first and a third layer of the first powder. The specific contact resistance between the first layer and the skutterudite layer for both the n-type and the p-type skutterudites subsequent to hot-pressing is less than about 10.0 .Math.cm.sup.2.

There is described a cascade-type compact hybrid energy cell (CHEC) that is capable of individually and concurrently harvesting solar, strain and thermal energies. The cell comprises an n-p homojunction nanowire (NW)-based piezoelectric nanogenerator and a nanocrystalline/amorphous-Si:H single junction cell. Under optical illumination of 10 mW/cm.sup.2 and mechanical vibration of 3 m/s.sup.2 at 3 Hz frequency, the output current and voltage from a single 1.0 cm.sup.2-sized CHEC was found to be 280 A and 3.0 V, respectivelythis is are sufficient to drive low-power commercial electronics. Six such CHECs connected in series were found to generate enough electrical power to light emitting diodes or drive a wireless strain gauge sensor node.