关键词: Ca3Co4O9;Bi掺杂;微观结构;热电性能

Abstract: Ca3-xBixCo4O9(0.0≤x≤0.45) samples were prepared by conventional solid-state reaction method and the effect of Bi doping on the microstructure and thermoelectric properties was investigated. XRD and SEM investigations revealed that c-axis-oriented structure could be formed in the Bi-containing samples.x=0.3 and 0.45 samples had larger degree of orientation and grain size, which resulted in larger conductivity in these samples. Since the substitution of Bi3+ for Ca2+ decreased the hole concentration, Seebeck coefficients of the samples increased with the increase of Bi content. The power factor of x=0.3 sample could reach 2.77×10-4 W/m·K2 at 1000 K, which was equal to that of Ca3Co4O9 sample prepared by the hot-pressing method.

Key words: Ca3-xBixCo4O9(0.0≤x≤0.45) samples were prepared by conventional solid-state reaction method and the effect of Bi doping on the microstructure and thermoelectric properties was investigated. XRD and SEM investigations revealed that c-axis-oriented structure could be formed in the Bi-containing samples.x=0.3 and 0.45 samples had larger degree of orientation and grain size, which resulted in larger conductivity in these samples. Since the substitution of Bi3+ for Ca2+ decreased the hole concentration, Seebeck coefficients of the samples increased with the increase of Bi content. The power factor of x=0.3 sample could reach 2.77×10-4 W/m·K2 at 1000 K, which was equal to that of Ca3Co4O9 sample prepared by the hot-pressing method.