Optimising the thermoelectric properties of Bi2Sr2Co2Oy using Ag substitution and Nano-SiC doping

Bi2Sr2Co2Oy with excellent thermoelectric properties has received extensive attention from scientific researchers. In this study, Bi2Sr2Co2Oy ceramic samples were prepared using the solid-phase sintering method. By Ag+ substitution for Bi3+, the hole concentration and electrical conductivity were optimised. On this basis, nano-SiC particles were introduced to increase grain boundaries, improve phonon scattering, reduce the mean free path of phonons, and reduce the lattice thermal conductivity. A sample with a nominal composition of Bi1.8Ag0.2Sr2-Co2Oy + 0.025 wt% SiC had a maximum ZT value of 0.35 at 923 K, which was approximately 67 % higher than the ZT value of pure Bi2Sr2Co2Oy. These results confirmed that under the combined action of Ag substitution and SiC doping, the thermoelectric performance of Bi2Sr2Co2Oy was significantly improved.