The effects of dual doping on the thermoelectric properties of Ca_{3鈭?span style='font-style: italic'>x}M_xCo_{4鈭?span style='font-style: italic'>y}Cu_yO₉ (M = Na, La)

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• 作者：Y. Ou^a ; ^b ; ¹ ; J. Peng^a ; ¹ ; F. Li^c ; Z.X. Yu^c ; F.Y. Ma^b ; S.H. Xie^a ; ^b ; J.-F. Li^c ; J.Y. Li^b ; ^jjli@uw.edu
• 关键词：Thermoelectric oxide ; Dual doping ; Sol&ndash ; gel process ; Spark plasma sintering
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：15 June, 2012
• 卷：526
• 期：Complete
• 页码：139-144
• 文件大小：1920 K

摘要

The effects of dual doping on the thermoelectric properties of Ca_3鈭?em>xM_xCo_3.8Cu_0.2O₉ (M = Na, La, x = 0.1, 0.2, 0.3) have been systematically investigated, with Ca_3鈭?em>xM_xCo_3.8Cu_0.2O₉ powders synthesized using sol-gel method, and then consolidated into bulk ceramics by spark plasma sintering. It is found that dual doping by Cu and La results in substantial increase in electric conductivity and small decrease in Seebeck coefficient, while dual doping by Cu and Na increase Seebeck coefficient and decrease electric conductivity slightly. Both types of doping enhance power factor and reduce thermal conductivity simultaneously in general, with substantial reduction in thermal conductivity observed in dual doping of Cu and La. These lead to enhancement in thermoelectric figure of merit by both types of doping in general, with ZT value of Ca_2.8La_0.2Co_3.8Cu_0.2O₉ 78.07%higher than Ca₃Co₄O₉ and 57.36%higher than Ca₃Co_3.8Cu_0.2O₉ near 773 K. These results suggest that dual doping by Cu and La is effective in enhancing thermoelectric figure of merit of Ca₃Co₄O₉.