Thermoelectric properties of P-type Yb-filled skutterudite YbxFeyCo4-ySb12

► We use graphite crucible to avoid the deleterious reaction during skutterudite synthesis to minimize the impurity phases. ► Fully filled p-type skutterudite YbFe4Sb12 has a high power factor over 30 μW/cm-K2 around 800 K. ► Lattice thermal conductivity of YbxFeyCo4-ySb12 is reduced due to combined effects from rare earth filling and Fe substitution for Co.