Abstract Here, the thermoelectric (TE) properties of Na0.74Co 1 − x NbxO2 ( x = 0.05 , 0.10 ) compounds are investigated experimentally and computationally. The experimental measurements are conducted in 300 − 620 K. Positive sign of Seebeck coefficient for both the compounds indicates the dominating p-type character. The maximum experimental values of ZT are observed as ∼ 0.12 and ∼ 0.19 at 620 K for x = 0.05 and x = 0.10 , respectively. The experimental transport properties of these compounds are understood by employing spin-polarized GGA+U (= 4 eV) electronic structure calculations on x = 0.0625 compound. On the basis of best experimental and computational matching of transport properties, we have estimated ZT till 1200 K computationally. The highest calculated values of ZT are ∼ 1.36 and ∼ 1.22 at 1200 K for x = 0.05 and x = 0.10 , respectively. The optimum value of efficiency for x = 0.05 is calculated as ∼ 6.4%, whereas it reaches ∼ 7.5% for x = 0.10 .

中文翻译：

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研究 Na0.74Co1−xNb O2 (x = 0.05,0.10) 在高温区域的热电特性

摘要 这里，Na0.74Co 1 - x NbxO2 ( x = 0.05 , 0.10 ) 化合物的热电 (TE) 性质通过实验和计算进行了研究。实验测量在 300 - 620 K 下进行。两种化合物的塞贝克系数的正号表示主要的 p 型特征。当 x = 0.05 和 x = 0.10 时，在 620 K 下观察到 ZT 的最大实验值分别为 ~ 0.12 和 ~ 0.19。通过对 x = 0.0625 化合物进行自旋极化 GGA+U (= 4 eV) 电子结构计算，可以了解这些化合物的实验传输特性。基于输运特性的最佳实验和计算匹配，我们通过计算估计了 ZT 到 1200 K。当 x = 0.05 和 x = 0.10 时，ZT 的最高计算值为 ~ 1.36 和 ~ 1.22，在 1200 K 时，分别。x = 0.05 时的最佳效率值计算为 ~ 6.4%，而 x = 0.10 时达到 ~ 7.5%。