Bi- and Cu-substituted Ca3Co4O9 samples were prepared by conventional solid-state reaction method and the effect of element substitution on the microstructures and thermoelectric properties was investigated. Partial s...Bi- and Cu-substituted Ca3Co4O9 samples were prepared by conventional solid-state reaction method and the effect of element substitution on the microstructures and thermoelectric properties was investigated. Partial substitution of Cu for Co leads to an increase in electrical conductivity and a decrease in Seebeck coefficient due to the rise of hole concentration. The microstructure of Cu-substituted sample is almost unchanged compared with undoped Ca3Co4O9. On the other hand, partial substitution of Bi for Ca gives rise to a significant increase in the grain size, and c-axis-oriented structure can be formed in Ca2.7Bi0.3Co4O9, resulting in an obvious increase in electrical conductivity. Cu and Bi co-substitution further increases the grain growth and the electrical conductivity of Ca2.7Bi0.3Co3.7Cu0.3O9. Thus, Cu and Bi co-substitution samples possess the optimal thermoelectric performance at high temperature and the highest value of power factor can reach 3.1×10^-4 Wm^-1.K^-2 at 1000 K.展开更多
Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated....Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated.The partial substitution of Cu for Co in Bi2Ba2Co2-xCuxOy led to an increase in the electrical conductivity because of an increase in the hole concentration and grain size of sintered bodies.In addition,Cu substitution led to an increase in Seebeck coefficients while kept the thermal conductivity unchanged.The highest thermoelectric figure of merit（ZT value） was obtained in x=0.4 sample and the value was 1.5 times as large as that of Cu-free sample at 873 K.展开更多
基金supported by the Foundation for University Key Teacher of Henan Province, China (2008136)Doctoral Fund of Henan Institute of Engineering(D2007011), China
文摘Bi- and Cu-substituted Ca3Co4O9 samples were prepared by conventional solid-state reaction method and the effect of element substitution on the microstructures and thermoelectric properties was investigated. Partial substitution of Cu for Co leads to an increase in electrical conductivity and a decrease in Seebeck coefficient due to the rise of hole concentration. The microstructure of Cu-substituted sample is almost unchanged compared with undoped Ca3Co4O9. On the other hand, partial substitution of Bi for Ca gives rise to a significant increase in the grain size, and c-axis-oriented structure can be formed in Ca2.7Bi0.3Co4O9, resulting in an obvious increase in electrical conductivity. Cu and Bi co-substitution further increases the grain growth and the electrical conductivity of Ca2.7Bi0.3Co3.7Cu0.3O9. Thus, Cu and Bi co-substitution samples possess the optimal thermoelectric performance at high temperature and the highest value of power factor can reach 3.1×10^-4 Wm^-1.K^-2 at 1000 K.
基金supported by the Foundation for University Key Teacher of Henan Province,China(No. 2008136)the Program for Innovative Research Team (in Science and Technology) in Henan Institute of Engineering(No.2009IRTHNIE05)
文摘Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated.The partial substitution of Cu for Co in Bi2Ba2Co2-xCuxOy led to an increase in the electrical conductivity because of an increase in the hole concentration and grain size of sintered bodies.In addition,Cu substitution led to an increase in Seebeck coefficients while kept the thermal conductivity unchanged.The highest thermoelectric figure of merit（ZT value） was obtained in x=0.4 sample and the value was 1.5 times as large as that of Cu-free sample at 873 K.
