Enhanced Thermoelectric Properties of CoSb₃-Based Skutterudite by Incorporating Reduced Graphene Oxide

We report a strategy for enhancing thermoelectric properties in CoSb₃-based skutterudite through the incorporation of reduced graphene oxide (RGO). Double-filled <i>n</i>-type CoSb₃ (SKD) powder was obtained by encapsulated induction melting and grinding. The SKD-RGO hybrid powder was prepared by coating graphene oxide (GO) onto the SKD powder and followed by a chemical reduction process. The hybrid powder was consolidated into the SKD-RGO bulk composites by spark plasma sintering. Advantageous effects of the RGO incorporation both on the charge and phonon transports were observed in the composites. The electrical conductivity of the composites increased with increasing the RGO content. Although the incorporation of RGO reduced the Seebeck coefficient due to the increase in the carrier concentration, the composites exhibited an improved power factor. Furthermore, lattice thermal conductivity in the composites decreased due to an additional phonon scattering at SKD/RGO interfaces. This study suggests that the incorporation of carbon nanomaterials is a promising way to the simultaneous control of the charge and thermal transports for realizing high thermoelectric performance in skutterudite materials.