The energy efficiency center of Moscow Iron and Steel Institute of Russian National Research University has developed a new material for thermoelectric conversion. Because of its high quality factor, the material can be used as a battery for long-term power supply of spacecraft. The results were published in the Journal of Materials Chemistry A Scientific Journal.

In principle, the thermoelectric conversion material is composed of two kinds of atoms with different properties, which are strictly fixed on the crystal lattice nodes and free oscillating atoms. Fixed atoms ensure high conductivity of materials, weak bond energy between oscillating atoms and lattices, and heat dissipation, which can greatly reduce the thermal conductivity of materials. In materials science, the prepared materials are intermetallic compounds (compounds of two or more metals), which have holes in the lattice structure. Without destroying the lattice structure, using "guest" atoms to fill the holes, the performance of different materials can be "matched". If the conductivity of the material is high and the thermal conductivity is weak, the thermoelectric quality factor (thermoelectric conversion effect), the key technical index of the material, is high.

The raw material selected by the Energy Efficiency Center of Moscow Iron and Steel Institute is cobalt ore material, which is composed of antimony and cobalt intermetallic compound (CoSb3). When the surface temperature difference reaches 400-500 C, the quality factor of the developed material reaches 1.4 (for reference, the known thermoelectric conversion material bismuth telluride, when the temperature difference is 100-150 C). At the same time, the quality factor reached the maximum of 1.2.

In order to obtain higher quality factor in antimony-cobalt system, the center has tried many technical schemes, such as using rare earth elements (such as ytterbium) as impurity components to hybrid materials, and using two or more metals to synthesize. Three metal elements have been used to synthesize quality factor of 1.8. Material Science. In addition, the material can be synthesized in a short time (no more than 2 minutes) by changing the ratio of metal composition and using indium as hybrid component. The quality factor of the material obtained after annealing for 5 hours is very high. The technical scheme has the advantage of low cost and high quality factor (up to 1.5). It has created a record of thermoelectric conversion index of antimony-cobalt metal system with indium as hybrid component.

The phenomenon that thermal energy can be directly converted into electricity was discovered by Thomas Sebeck, a German physicist, in 1821, but the Sebeck effect has not been industrialized so far. Researchers have been trying to develop thermoelectric direct conversion materials, but all attempts are at the laboratory stage.

Thermoelectric conversion materials have been applied in space field. Thermoelectric conversion devices using nuclear fission as heat source are installed on Cassin, New Horizons spacecraft and Curiosity Mars probe.