Influence of Ru Substitution on the Thermoelectric Properties of Ce(Fe

概要

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In this work, Ru substituted p-type skutterudites Ce<inf>y</inf>(Fe<inf>1-x</inf>Ru<inf>x</inf>)<inf>4</inf>Sb<inf>12</inf>are synthesized by melting-annealing method. XRD and EPMA analysis show that, the solubility of Ru in Ce<inf>y</inf>(Fe<inf>1-x</inf>Ru<inf>x</inf>)<inf>4</inf>Sb<inf>12</inf>could reach 50%. Because Ru substitution is an isoelectronic alloying at Fe sites, the power factors of Ce<inf>y</inf>(Fe<inf>1-x</inf>Ru<inf>x</inf>)<inf>4</inf>Sb<inf>12</inf>are similar with CeFe<inf>4</inf>Sb<inf>12</inf>when Ru content is below x = 0.3. However, Ru substitution could reduce the hole effective mass, therefore, high Ru content would result in a gradually decreased Seebeck coefficient and then deteriorate the electrical properties. Because of the mass fluctuation, the isoelectronic alloying at the Fe site by Ru lowers the thermal conductivity, nevertheless, simulation analysis shows that Callaway--Klemens' model should be modified with an additional adjustment due to the ``filling'' scattering. Finally, when the Ru content is x = 0.3, the \kappa_{\text{L}} is depressed by 30% comparing with CeFe<inf>4</inf>Sb<inf>12</inf>, and the ZT_{\text{max}} value could reach 0.95 at 850 K.
2013-12-15