Collective Effect of Fe and Se To Improve the Thermoelectric Performance of Unfilled p-Type CoSb3 Skutterudites

Abstract

Filled skutterudites constitute an important class of efficient and stable thermoelectric materials for power generation; however, their commercialization has been hampered due to the usage of expensive rare-earth elements as “fillers” and the nonavailability of the efficient and compatible p-type counterpart. In view of this, we report a state-of-the-art thermoelectric figure of merit (ZT) in rare-earth-free p-type unfilled CoSb3 skutterudite co-doped with Fe and Se, synthesized using a facile process of arc-melting and spark plasma sintering, which is both fast and scalable. The doping of Fe and Se have been chosen in accordance with the first-principles-based density functional theory (DFT) calculations which suggested that Fe leads to p-type conduction in CoSb3, while Se strengthens the thermoelectric properties. The experimental results also suggest that the optimized partial substitutional doping of Fe at the Co-site and Se at the Sb-site in CoSb3 leads to a favorable tuning of the electrical and th...