文摘
A rapid route of synthesizing pristine Co4Sb12 at relatively low temperature was previously developed. However, filling the voids using the same procedure is not successful. We develop a new route to fabricate In-filled cobalt skutterudites with InSb nanoinclusions InxCo4Sb12–(InSb)y via solid–vapor reaction between hydrothermally synthesized Co4Sb12 powder and the indium chunk. The nanocomposites are characterized using powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS). With the success of partial filling of In into the voids and InSb nanoinclusions, the power factor of the InxCo4Sb12–(InSb)y nanocomposites is significantly enhanced, and the thermal conductivity is lowered as compared with the pristine Co4Sb12. As a result, ZT with its highest value of 1.0 is attained for the hierarchical structured In0.04Co4Sb12–(InSb)0.05 nanocomposite at 575 K. The attained ZT value is among the highest ever reported value at T ≤ 575 K for In-filled cobalt skutterudites.