Substantial enhancement of thermoelectric power factor of undoped CoSb₃ skutterudites processed by microwave sintering

In the present work, a new strategy combining the solvo-hydrothermal method with microwave sintering (MWS) technique was successfully employed to synthesize single phase p-type CoSb₃ skutterudite. The microwave sintered bulk materials with uniform grain size of 190 nm to 230 nm, and a compaction density of > 80% were obtained. The effect of microwave sintering conditions on thermoelectric properties is discussed in detail, where all the samples exhibit enhanced thermoelectric power factor. To achieve a large Seebeck coefficient and high electrical conductivity, the disordered structure was created in the ordered CoSb₃ nanocrystalline material by varying the microwave sintering temperature and duration. Maximum power factor of 1508.6 µWm^-1K^-2 was achieved at 663 K for microwave sintered sample at 600 °C for 10 min. The microwave-sintered samples show an enhanced thermoelectric power factor as compared to samples processed by conventional sintering techniques. The present study offers an effective strategy for the production of skutterudite materials with enhanced thermoelectric performance at a low cost. Graphical Abstract: (Figure presented.)