“…Reduction of the thermal conductivity has been achieved with unfilled CoSb 3 , by including for instance nanoparticles of CoSb 3 [19,20], FeSb 2 [21], InSb [22], C 60 [23], or ZrO 2 [24]. Nanoprecipitates produced in situ led also to interesting results: Yb 2 O 3 in Yb y Co 4 Sb 12 [25], InSb in In x Ce y Co 4 Sb 12 [26], or FeSb 2 in Co 0.9 Fe 0.1 Sb 3 [27].…”