Enhanced thermoelectric performance of Bi1.9Mg0.1Sr2Co2Oy/SiC composites via SiC nanoparticle incorporation

The influence of SiC nanoparticles on hole transport and thermoelectric properties in Bi1.9Mg0.1Sr2Co2Oy/SiC composites was systematically investigated. Incorporating a small amount of SiC nanoparticles (0.02 wt%) simultaneously enhanced electrical conductivity and the Seebeck coefficient through increases in hole concentration and interface-related carrier-filtering effects, respectively. Thermal conductivity was governed by two competing effects: enhanced phonon scattering at the matrix/SiC interfaces and the high intrinsic thermal conductivity of SiC. The composite containing 0.02 wt% SiC exhibited the highest dimensionless figure-of-merit (ZT) of 0.172 at 973 K. Pearson correlation analysis quantitatively revealed the relationships among SiC content, hole transport, and thermoelectric parameters. By integrating thermoelectric measurements with Pearson correlation analysis, the dominant transport mechanisms governing thermoelectric performance were systematically clarified. These integrated investigations provide a quantitative analytical framework for optimizing thermoelectric properties in Bi1.9Mg0.1Sr2Co2Oy/SiC composites.