High pressure synthesis of p-type Fe-substituted CoSb3 skutterudites

Fe-substituted CoSb3 skutterudites were successfully synthesized with high pressure synthesis method. The composition, structure, and thermoelectric properties were investigated. Co4−x Fe x Sb12 samples have the skutterudite structure of \(\text{Im} \bar{3}\) symmetry. The hole concentration increases with elevating Fe substitution level. Compared with those ambient-pressure synthesized Fe-substituted CoSb3 samples, our samples exhibit enhanced power factor and suppressed thermal conductivity which benefitted from high pressure. The optimal Co3.2Fe0.8Sb12 shows a peak ZT of 0.53 at 823 K, the highest value for Co-rich p-type skutterudites with single-element substitution. Current study on Co4−x Fe x Sb12 provides a basis for further thermoelectric performance enhancement of Co-rich p-type skutterudites.