04.27.12

Design of Bulk Nanocomposites as High Efficiency Thermoelectric Materials

Scientific Achievement

A newly synthesized bulk thermoelectric material that contains nanocrystals with the same orientation and structure as the host material breaks thermoelectric efficiency records by blocking thermal, but not electrical, conductivity.

Significance and Impact

A new strategy to design inexpensive materials that more efficiently convert heat to electricity.

Research Details
  • Thermoelectric materials directly generate electrical power from heat, but suffer from low efficiency, lack of stability, and cost.
  • Thermoelectric materials are ranked by the figure of merit (ZT)
    • Max with low thermal conductivity and high charge transport.
  • Nanostructuring in bulk materials dramatically reduces the thermal conductivity, but usually decreases charge transport
  • Inclusion of aligned nanocrystals with similar lattice parameter, symmetry and structure reduces the thermal conductivity without affecting the electron transport - increasing ZT.

Bulk Thermoelectric



Left: TEM image shows that strontium telluride forms 1 - 15 nm crystals with the same orientation and structure as the surrounding lead telluride thermoelectric material. Right: The dimensionless figure of merit (ZT) of these nanocomposites reaches 1.7 at 815 K, better than any previously reported p-type "hole" conductor.



Reference: Kanishka Biswas, Jiaqing He, Qichun Zhang, Guoyu Wang, Ctirad Uher, Vinayak P. Dravid and Mercouri G. Kanatzidis, Strained endotaxial nanostructures with high thermoelectric figure of merit, Nature Chemistry 2, 160 (2011) [DOI: 10.1038/nchem.955External link].

Support: Work was performed at Northwestern University, Argonne National Laboratory and the University of Michigan and supported by the Office of Naval Research and the Revolutionary Materials for Solid State Energy Conversion (RMSSEC), an EFRC led by Don Morelli at the University of Michigan.

Last modified: 3/27/2013 12:23:29 PM