Ultra-High Temperature Thermoelectrics

Hypersonic vehicles need compact, high temperature capable power sources since batteries are not sufficiently compact and require insulation. A thermoelectric (TE) energy-harvesting system converts thermal energy into electricity by taking advantage of the temperature difference between two surfaces. The objective of this effort is to increase the temperature limits of current TE materials from approximately 600 ºC to 1250 ºC while achieving a figure of merit (ZT) above 1. Since the energy output of TE generators is a function of the temperature difference between hot and cold sides, the output will be dependent on the generators’ ability to separate the hot and cold sides with insulating or phase change materials. Theoretical and experimental studies have shown that low-dimensional TE materials, such as super-lattices, quantum dots, and nanofibers, can enhance the figure of merit (ZT). To increase the ZT, eM TECH proposes to specifically develop silicon carbide (SiC) ceramic nanofibers that will be electro-spun from ceramic precursors and the nanofibers will be encapsulated in aerogel thermal insulation to insulate the hot from the cold side to further improve the thermoelectric figure of merit.