Synthesis and high temperature thermoelectric properties of Ca_3.0−x−yNd_xNa_yCo₄O_9+δ

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• 作者：J. Pei ; G. Chen ; D.Q. Lu ; P.S. Liu ; N. Zhou
• 关键词：A. Semiconductors ; B. Sol– ; gel method ; D. Electrical conductivity ; D. Thermal conductivity
• 刊名：Solid State Communications
• 出版年：2008
• 期刊代码：101_00381098
• 类别：ms
• 出版时间：May 2008
• 卷：146
• 期：7-8
• 页码：283-286
• 文件大小：506 K

摘要

New polycrystalline Ca_3.0−x−yNd_xNa_yCo₄O_9+δ (decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVW-4S33N84-2&_mathId=mml30&_user=1067359&_cdi=5545&_rdoc=4&_acct=C000050221&_version=1&_userid=10&md5=5d7fe6def0aa04bee0654d70466cad9d" title="Click to view the MathML source" alt="Click to view the MathML source">x=0.0, 0.1, 0.2, 0.3; decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVW-4S33N84-2&_mathId=mml31&_user=1067359&_cdi=5545&_rdoc=4&_acct=C000050221&_version=1&_userid=10&md5=6df3e1783a3cefa37bfad6f49b908786" title="Click to view the MathML source" alt="Click to view the MathML source">y=0.0, 0.1) samples were prepared using a sol–gel method followed by hot-pressing sintering technique. Powder X-ray diffraction analysis showed that all the samples were single phase. The high-temperature (350 to 1073 K) thermoelectric properties of the samples were investigated. The substitution of Nd³⁺ for Ca_2.9Na_0.1Co₄O_9+δ resulted in the decrease of the electrical conductivity, thermal conductivity and the increase of the Seebeck coefficient. The electrical conduction was dominated by the small polaron hopping conduction mechanism in the temperature region above 550 K. Compared with Nd or Na single substitution, Nd and Na double substitution can further reduce thermal conductivity of Ca₃Co₄O_9+δ. The value of ZT reaches 0.29 for Ca_2.6Nd_0.3Na_0.1Co₄O_9+δ at 1073 K.