Simultaneously optimized thermoelectric and mechanical performance of p-type polycrystalline SnSe enabled by CNTs addition

Abstract

A series of SnSe/carbon nanotubes (SnSe/CNTs) composites, with homogeneous distribution of CNTs, were fabricated by combining solution synthesis with fast sintering. Enabled by CNTs addition, both the electrical conductivity and power factor are improved significantly; the lattice thermal conductivity is suppressed due to strengthened phonon scattering. As a result, a maximum zT of 0.90 is obtained in the SnSe/CNTs composite with 0.20 wt.% CNTs, ∼ 90% higher than that of SnSe. In addition, the composite with 0.35 wt.% CNTs exhibits a dramatically increased compressive strength of 135 MPa, representing an ∼ 81% increase. This work offers a composite design strategy for synergistically improving both thermoelectric and mechanical properties of polycrystalline SnSe.