Shockwave Fabrication of High Performance Thermoelectrics

Thermoelectric (TE) generators/refrigerators have the advantages of lack of moving parts, quiet operation, and flexibility in deployment, but their use has been limited because of their relatively low conversion efficiency. Two major loss components are conductive (phonon) heat transfer through the TE lattice and parasitic losses at fabrication interfaces. Shock wave consolidation of thermoelectric nanopowders to produce TE devices will reduce both loss sources, leading to enhanced efficiency devices. The conversion efficiency of a TE device will always be thermodynamically limited by the Carnot ratio of (Th-Tc)/Th, where Th and Tc are the temperatures of the hot and cold junctions. Present technology thermoelectric devices can provide conversion efficiencies up to a third of the Carnot limit. With the restrictions on phonon transport acruing from nanopowder consolidation, conversion efficiencies of over 50% of the Carnot limit should be possible.