Enhancing the Thermoelectric Properties and Delaying Their Attenuation in n‑Type SiGe Alloy through SiC Nanoparticle...

Due to its high operating temperature and excellent mechanical properties, SiGe alloy has become a typical representative of high-temperature thermoelectric materials and has been widely utilized in radioisotope thermoelectric generators (RTGs). However, its relatively high thermal conductivity poses an obstacle to the enhancement of the ZT value, thereby significantly restricting the future development of RTGs. This study involves the fabrication of n-type (Si_0.8Ge_0.2)_0.98P_0.02(SiC) _x alloy using high-energy ball milling followed by spark plasma sintering (SPS). Thanks to the composite effect of SiC and the SiGe matrix, nanopores were successfully introduced into the SiGe matrix. Consequently, the power factor improved while the thermal conductivity markedly decreased. The lowest thermal conductivity could be decreased to 2.08 W·m^-1·K^-1.The (Si_0.8Ge_0.2)_0.98P_0.02(SiC)_0.015 sample achieved a ZT value of 1.308 at 1023 K, with only a 2.4% reduction in thermoelectric performance after thermal aging. In summary, this paper puts forward an effective approach that can effectively improve the thermoelectric properties of SiGe alloy and delay the attenuation of these properties.