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. Co(4-x)Fex(S)b(12) samples have the skutterudite structure of Im (3) over bar 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-xFexSb12 provides a basis for further thermoelectric performance enhancement of Co-rich p-type skutterudites.