A new generation of p-type didymium skutterudites with high ZT

This work evaluates the influence of single, double and triple filling of didymium, Ca and Ba in Fe4Sb12 as well as in Fe3CoSb12 on the thermoelectric performance. Various filling levels, as well as various preparation methods and nanostructuring were used to improve the thermoelectric performance. It is shown that samples prepared via ball milling have a higher ZT (ZT = 1.1) than their hand milled counterparts (ZT ≈ 0.8). Co/Fe-substituted samples have ZT > 1.2 i.e. 25% higher than samples without Co, an average ZT up to 0.93 and an efficiency up to 14% for the temperature gradient of 300–800 K. With this good thermoelectric performance in such a wide temperature range these materials are hitherto the best p-type skutterudites for thermoelectric devices.