Room temperature thermoelectric properties of p-type CuMn_1.1−xE_xO₂ (E=Mg, Ca, Sr, x=0-0.2) ceramics

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• 作者：Cheng-Chung Hsieh^a ; Chii-Shyang Hwang^a ; ^{cshwang@mail.ncku.edu.tw" class="auth_mail" title="E-mail the corresponding author} ; Chia-Hung Kuo^b
• 关键词：CuMnO2 ; Substitution ; Layer structure ; Thermoelectric properties
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 February 2016
• 年：2016
• 卷：42
• 期：2
• 页码：2960-2968
• 全文大小：3853 K

文摘

CuMn_1.1−xE_xO₂ (E=Mg, Ca, Sr, x=0–0.2) bulks with a delafossite structure were prepared via solid-state reactions and sintered at 1253 K for 2.5 h in argon. The phase, microstructure, and thermoelectric properties of the CuMn_1.1−xE_xO₂ (E=Mg, Ca, Sr, x=0–0.2) samples were discussed using different cation substitution contents. The crystallinity and microstructure of the bulks were analyzed using X-ray diffraction and scanning electron microscopy, respectively. The thermoelectric properties of the bulks were studied at room temperature. Both different dopants and cation substitution contents affected the phases and thermoelectric properties of sintered bulks. Bulks with the crednerite CuMnO₂ phase were obtained in all samples, although the second phase Mn₃O₄ existed on Mg substitution samples with an x value of up to 0.15. The crednerite CuMn_1.1−xE_xO₂ (E=Mg, Ca, Sr, x=0–0.2) samples were p-type semiconductors. The thermoelectric properties of the CuMn_1.1−xE_xO₂ (E=Mg, Ca, Sr, x=0–0.2) bulks were enhanced by cation substitution, because electronic conductivity increased while thermal conductivity was suppressed and the Seebeck coefficient did not fall much. The CuMn_0.9Mg_0.2O₂ sample showed the lowest thermal conductivity and the largest ZT at room temperature. This study demonstrates that Mg substitution was highly effective for enhancing the room-temperature thermoelectric properties of CuMnO₂.