Enhanced thermoelectric properties of nano-SiC dispersed NaCo ₂ O ₄ composites

Sodium cobalt oxides (NaCo ₂ O ₄ ) have attracted considerable attention as promising high-temperature thermoelectric (TE) candidates. In this study, we choose nano-SiC as an inclusion to synthesize NaCo ₂ O ₄ -based composites using the solid-state method. The crystal structure and TE properties for nano-SiC dispersed NaCo ₂ O ₄ composites with different SiC contents are discussed. The results indicate that the SiC nanoparticles can suppress the grain growth and form many new grain boundaries and interface to reduce thermal conductivity observably. Moreover, the electrical conductivity and Seebeck coefficient can be improved by the energy filtering effect. Therefore, the maximum ZT of 0.122 is obtained from the samples with 0.2vol.% nano-SiC, approximately two times higher than that of pure NaCo ₂ O ₄ . This study provides a facile strategy to synthesize nanocomposites to enhance TE performance efficiently.