Lead-free AgSn4SbTe6 nanocomposites with enhanced thermoelectric properties by SiC nanodispersion

Lead-free p-type AgSn4SbTe6 based thermoelectric nanocomposites were fabricated by a process combining mechanical alloys (MA) and spark plasma sintering (SPS). It is found that dispersing SiC nanoparticles into the AgSn4SbTe6 matrix can enhance the thermoelectric properties significantly. SiC nanoinclusions can increase the power factor mainly due to improved electrical conductivity while slightly increasing the Seebeck coefficient, in addition to reducing the thermal conductivity through enhancing phonon scattering. A high dimensionless figure of merit (ZT) value up to 1.0 at a relatively low temperature (723 K) is achieved in AgSn4SbTe6 incorporated with a small amount (1 vol%) of SiC nanoparticles. This work validated the effectiveness of SiC nanodispersion in enhancing thermoelectric performance of AgSn4SbTe6, by which a simple process yields a high ZT equivalent to the record one reported for this materials fabricated by a melting process.