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PUBLICATIONS

Phase Equilibria, Crystal Chemistry and Thermoelectric Properties of Compounds in the Ca-Co-Zn-O System

Published

Author(s)

Winnie K. Wong-Ng, Tana Luo, Wenjie Xie, Weihua Tang, James A. Kaduk, Qingzhen Huang, Yonggao Y. Yan, Soma Chattopadhyay

Abstract

In the Ca-Co-Zn-O system, we have determined the tie-line relationships and the thermoelectric properties, solid solution limits, and structures of two low-dimensional cobaltite series, Ca3(Co, Zn)4O9 and Ca3(Co,Zn)2O6 at 885 C in air. In Ca3(Co,Zn)4O9 which has a misfit layered structure, Zn was found to substitute in the Co site to a limit of Ca3(Co3.8Zn0.2)O9. The compound Ca3(Co,Zn)2O6 (n=1 member of the homologous series, Can+2(Co,Zn)n(Co,Zn)’O3n+3) consists of 1-dimensional parallel (Co,Zn)2O66- chains that are built from successive alternating face-sharing (Co,Zn)O6 trigonal prisms and ‘n’ units of (Co,Zn)O6 octahedra along the hexagonal c-axis. Zn substitutes in the Co site of Ca3Co2O6 to a small amount of approximately Ca3(Co1.95 Zn0.05)O6. In the ZnO-CoOx system, Zn substitutes in the Co site of Co3O4 to the maximum amount of (Co2.49Zn0.51)O4 and Co substitutes in the Zn site of ZnO to (Zn0.94Co0.06)O. The crystal structures of (Co2.7Zn0.3)O4, (Zn0.94Co0.06)O and Ca3(Co1.95Zn0.05)O6 are described. Despite the Ca3(Co, Zn)2O6 series having reasonably high Seebeck coefficients and relatively low thermal conductivity, the electrical resistivity values of its members are too high to achieve high figure of merit, ZT.
Citation
Journal of Applied Physics
Volume
184
Pub Type
Journals

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DOI Link

Keywords

Ca-Co-Zn-O phase equilibria, structure of Ca3(Co1.95Zn0.05)O6, structure of (Co2.7Zn0.3)O4, thermoelectric properties of Ca3(Co, Zn)4O9 and Ca3(Co, Zn)2O6. Ca-Co-Zn-O phase equilibria, structure of Ca3(Co1.95Zn0.05)O6, structure of (Co2.7Zn0.3)O4, thermoelectric properties of Ca3(Co, Zn)4O9 and Ca3(Co, Zn)2O6. Ca-Co-Zn-O phase equilibria, structure of Ca3(Co1.95Zn0.05)O6, structure of (Co2.7Zn0.3)O4, thermoelectric properties of Ca3(Co, Zn)4O9 and Ca3(Co, Zn)2O6.
Energy

Citation

Wong-Ng, W. , Luo, T. , Xie, W. , Tang, W. , Kaduk, J. , Huang, Q. , Yan, Y. and Chattopadhyay, S. (2011), Phase Equilibria, Crystal Chemistry and Thermoelectric Properties of Compounds in the Ca-Co-Zn-O System, Journal of Applied Physics, [online], https://doi.org/10.1016/j.jssc.2011.06.01 (Accessed May 2, 2024)

Created June 21, 2011, Updated November 10, 2018