Nanoporous PbSe-SiO₂ Thermoelectric Composites.

ABSTRACT: Nanoporous architecture has long been predicted theoretically for its proficiency in suppressing thermal conduction, but less concerned as a practical approach for better thermoelectric materials hitherto probably due to its technical challenges. This article demonstrates a study on nanoporous PbSe-SiO₂ composites fabricated by a facile method of mechanical alloying assisted by subsequent wet-milling and then spark plasma sintering. Owing to the formation of random nanopores and additional interface scattering, the lattice thermal conductivity is limited to a value as low as 0.56 W m^-1 K^-1 at above 600 K, almost the same low level achieved by introducing nanoscale precipitates. Besides, the room-temperature electrical transport is found to be dominated by the grain-boundary potential barrier scattering, whose effect fades away with increasing temperatures. Consequently, a maximum ZT of 1.15 at 823 K is achieved in the PbSe + 0.7 vol% SiO₂ composition with >20% increase in average ZT, indicating the great potential of nanoporous structuring toward high thermoelectric conversion efficiency.

SUBMITTER: Wu CF 

PROVIDER: S-EPMC5700627 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature