Enhanced thermoelectric performance of β-Zn4Sb3 based composites incorporated with large proportion of nanophase Cu3SbSe4

Thermoelectric properties of β-Zn4Sb3 based composites, Cu3SbSe4/β-Zn4Sb3, incorporated with large volume fraction, f (10-20 vol.%), of p-type nanophase Cu3SbSe4 have been investigated. The results indicate that as Cu3SbSe4 with a relatively lager thermopower, S, and a greater carrier mobility, μ, is incorporated into β-Zn4Sb3, the S of the composite system increases greatly, and at T > 500 K thermoelectric power factor (PF) becomes larger than that of the β-Zn4Sb3 matrix due to increased mobility of the composites. Especially, for the composite system with 15 vol.% of Cu3SbSe4, an increase of ∼30% in the PF and a reduction of ∼40% in the total thermal conductivity are achieved at 648 K, which allow the thermoelectric figure of merit (ZT) to reach 1.23 (at 648 K), a value that is 1.6 times larger than that (0.75) of matrix, β-Zn4Sb3 in the present study. Our results suggest that incorporation of secondary phase with larger S and greater μ in large proportion in a host material could be an easy, direct and effective way to elevate the thermoelectric performance of the host.