Enhanced thermoelectric properties of Bi1.92Li0.08Sr2Co2Oy/x wt% SiC composites

In this work, Bi1.92Li0.08Sr2Co2Oy/x wt% SiC (1.0 <= x <= 4.0 wt%) composites are fabricated through a solid-state reaction followed by spark plasma sintering. The resulting composites exhibit plate-like grains and high density. The addition of SiC nanoparticles reduces electrical conductivity due to decreased hole mobility and increases the Seebeck coefficient due to an enhanced scattering factor and effective mass. Furthermore, the incorporation of SiC nanoparticles significantly enhances phonon scattering, thereby reducing phonon thermal conductivity. The Bi1.92Li0.08Sr2Co2Oy/2.0 wt% SiC composite exhibits the largest ZT of 0.17 at 973 K due to its high Seebeck coefficient and low thermal conductivity. Our results demonstrate that incorporating SiC nanoparticles is a highly effective strategy for enhancing the thermoelectric properties of Bi1.92Li0.08Sr2Co2Oy.