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http://dx.doi.org/10.4191/KCERS.2009.46.6.689

Determination of the Thermolelectric Properties of NaxCo2O4 by Controlling the Concentration of Na and Additive  

Choi, Soon-Mok (Korea Institute of Ceramic Engineering and Technology(KICET))
Jeong, Seong-Min (Korea Institute of Ceramic Engineering and Technology(KICET))
Seo, Won-Seon (Korea Institute of Ceramic Engineering and Technology(KICET))
Publication Information
Journal of the Korean Ceramic Society / v.46, no.6, 2009 , pp. 689-694 More about this Journal
Abstract
Layer-structured $Na_xCo_2O_4$ was synthesized from $Na_2CO_3\;and\;Co_3O_4$ powders. The chemical concentrations of Na and additive were controlled to enhance the thermoelectric properties over the temperature range from 400 K to 1,150 K. As a result, we obtained the maximum thermoelectric properties at a single phase region with Na content of x=1.5. When Na content was smaller than x=1.5, the thermoelectric properties was low due to formation of second phases of CoO and other oxides. Additionally, Mn was doped to improve thermoelectric properties by means of decreasing thermal conductivity. The results showed that the concentrations of both Na and Mn are all governing factors to determine the thermoelectric properties of $Na_xCo_2O_4$ system.
Keywords
Thermoelectrics; $Na_xCo_2O_4$; Nonstoichiometry; Mn; p-type semiconductor;
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