Thermoelectric properties in double-filled skutterudites InxNdyCo4Sb12

► We successfully introduce In and Nd into CoSb3 skutterudites by the inductive melting method. ► We explore simultaneously enhancing the power factor and ZT through Nd and In double filling. ► The attained largest power factor 3.2 m Wm−1 K−2 (360 K) is comparable to Ba and In filled CoSb3. ► We reveal that In and Nd filling is indeed efficient in improving thermoelectric properties.