Enhanced thermoelectric properties of p-type CoSb3/graphene nanocomposite

Abstract

Nanostructuring and second phase incorporation are considered to be promising ways of enhancing the thermoelectric performance of bulk materials. Here, a design principle is proposed which combines these two methods for improving the thermoelectric performance of p-type CoSb₃ by fabricating a CoSb₃/graphene (CoSb₃/G) nanocomposite, where a second phase, graphene, is introduced in the nanostructured CoSb₃ matrix via an in situ one-pot solvothermal route. In addition, CoSb₃/G bulk materials were prepared by hot pressing the solvothermally synthesized CoSb₃/G powder. It was found that addition of a small amount of graphene can drastically enhance the electrical conductivity due to the increase in both carrier concentration and mobility. In addition, the well dispersed graphene in the nanostructured CoSb₃ matrix also contributes to the low lattice thermal conductivity. A dimensionless figure of merit ZT = 0.61 at 800 K has been obtained for the CoSb₃/G nanocomposite, which is about a 130% improvement over that of graphene-free CoSb₃ (∼0.26).