High Pressure Synthesis of p-Type CeFeCoSb Skutterudites.

Co-substituted p-Type CeFeCoSb skutterudites were successfully synthesized with a high pressure synthesis method. The structure, composition, and thermoelectric properties were investigated. The obtained CeFeCoSb samples show the skutterudite structure of I m 3 ¯ symmetry. The hole concentration decreases with elevating Co substitution level, leading to increased Seebeck coefficient and electrical resistivity. Meanwhile, the filling fraction of Ce decreases, which is unfavorable for reducing the lattice thermal conductivity. As a result, the thermoelectric performance of CeFeCoSb deteriorates with higher Co content. The maximal ZT of 0.91 was achieved at 763 K for the optimal CeFe₄Sb sample.