Hybrid composite approach enhancing the thermoelectric performance of p-type iron-silicide synthesized by the arc melting-spark plasma sintering technique

Iron-silicide ( β -FeSi 2 ) is one of the most suitable and compatible thermoelectric compounds in applications of mid-temperature thermoelectric energy conversion technologies. Iron-silicide has the added advantages of low cost, non-toxicity, and thermal stability. Apart from these merits, their low figure of merit makes them inferior to others. We experimented with the SiGe particles incorporation into the β -FeSi 2 matrix to address these issues. The varying weight percentage of SiGe particle addition in FeSi 2 was made using the SPS compaction technique. Adding SiGe particles in Al-doped β -FeSi 2 resulted in a lower thermal conductivity than pristine compounds. Also, adding 12 wt% SiGe leads to a 34 % reduction in thermal conductivity values, primarily due to increased phonon scattering mechanisms. Moreover, the Seebeck coefficient exhibits notable improvements, resulting in an excellent thermoelectric performance of the p-type β -FeSi 2 compound. The figure-of-merit ( zT ) value of 0.19 was achieved in β -FeSi 1.9 Al 0.1 –12 wt % SiGe composite, a 57 % increase, compared to pristine β -FeSi 1.9 Al 0.1 compounds.