The efficient strategies to minimize thermal conductivity in skutterudite materials are creating point defects along with nanosized grains. In this report, Sn and Se co-doped CoSb₃ materials were synthesized through mixed-ball milling and spark plasma sintering techniques to utilize this strategy. Their phases, microstructure and thermoelectric properties were investigated under the content variation of Sn and Se in CoSb₃ samples. The experimental results revealed that the Sn and Se were substituted at Sb sites in CoSb₃ crystal structure and grain sizes were restricted to a hundred nanometer. The lattice thermal conductivity was reduced to 2.4W/mK at 298K. Interestingly, increasing Sn and Se doped content could further minimize the lattice thermal conductivity. The lowest value at room temperature is 1.79W/mK for CoSb2.70Sn0.150Se0.150 which was dramatically lower than pure CoSb₃. Moreover, the increment of Sn and Se content also increased the electrical conductivity of doped samples, while the negative Seebeck coefficient sign tended to decrease. As expected, low electrical conductivity and substantial reduction in the Seebeck coefficient of doped samples at high measurement temperature, resulting in low power factor and low ZT values. It was clearly seen that the highest power factor of 880μW/mK² was found at 516K in CoSb2.65Sn0.175Se0.175. Furthermore, it also dominated the highest ZT value of 0.29 at 565 K, compared to the other Sn and Se co-doped samples. From these results, ball milling under dry conditions followed by wet conditions not only allowed a longer milling process but also generated a small fraction of pore which was a part of the reduction in thermal conductivity. Especially, the advantage of the existence of Sn and Se point defects and nanosized grains from this work will be escalated when it was applied to prepare materials that have high power factor values.

中文翻译：

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通过混合球磨和火花等离子烧结将点缺陷和纳米化晶粒相结合，以最小化 Sn 和 Se 共掺杂 Cosb3 的晶格热导率

使方钴矿材料的热导率最小化的有效策略是产生点缺陷以及纳米尺寸的晶粒。在本报告中，通过混合球磨和放电等离子烧结技术合成了Sn 和 Se 共掺杂 CoSb _{3材料，以利用该策略。在CoSb 3}样品中Sn和Se含量变化的情况下，研究了它们的相、微观结构和热电性能。实验结果表明，Sn和Se在CoSb ₃晶体结构中的Sb位点被取代，晶粒尺寸被限制在100纳米。晶格热导率降至2.4298K 时的 W/mK。有趣的是，增加 Sn 和 Se 掺杂含量可以进一步降低晶格热导率。室温下最低值为1.79用于 CoSb 的 W/mK2.70锡0.150硒0.150这大大低于纯CoSb ₃。此外，Sn和Se含量的增加也增加了掺杂样品的电导率，而负塞贝克系数符号趋于减小。正如预期的那样，在高测量温度下，掺杂样品的低电导率和塞贝克系数显着降低，导致低功率因数和低 ZT 值。可以清楚的看到最高功率因数880μW/mK ²发现于 516钴中的钾2.65锡0.175硒0.175. 此外，与其他 Sn 和 Se 共掺杂样品相比，它还在 565 K 时占据了 0.29 的最高 ZT 值。从这些结果来看，在干燥条件下球磨，然后在湿条件下球磨不仅允许更长的研磨过程，而且还产生了一小部分孔隙，这是热导率降低的一部分。特别是，当将其应用于制备具有高功率因数值的材料时，该工作中存在的 Sn 和 Se 点缺陷和纳米级晶粒的优势将得到升级。