Na填充型方钴矿化合物CoSb3的高压合成及电输运特性研究

 利用高压合成方法，在压力为2 GPa、温度为900 K的条件下，以NaN₃作为添加剂，成功地合成出了Na填充型的方钴矿化合物CoSb₃。X射线衍射（XRD）研究结果表明，当Na填充量达80%时，合成的Na填充型方钴矿化合物CoSb₃仍为单相方钴矿结构，没有Na和NaN₃等杂质峰。在室温下对不同Na填充量的样品进行了电阻率（ρ）和Seebeck系数（α）的测试，研究了不同Na填充量对样品电阻率、Seebeck系数和功率因子（α²σ）的影响。研究结果表明：室温下，样品的电导率随Na填充量的增加而增大，Seebeck系数的绝对值随Na填充量的增加而减小。当Na填充量为0.4时，样品获得了最高的功率因子（8.72 μW·cm^-1·K^-2），此值高于He等报道的利用热压法制备的CoSb₃的值。填充量对样品电输运特性的影响规律与Pei等研究的K填充型CoSb₃的研究结果相一致。上述研究结果表明，高压合成技术有利于提高填充型方钴矿化合物的填充量，并有效地提高样品的电输运特性。

Synthesis and Electric Transport Properties of Na-Filled CoSb_3 at High-Pressure

Skutterudite compounds Na-filled CoSb₃ were successfully synthesized at high-pressure using powders of Co, NaN₃ and Sb as starting materials. The X-ray diffraction (XRD) results indicate that all samples have the single phase CoSb₃. No secondary phase is found when Na content w_Na≤80%. The composition-dependent electric transport properties of Na-filled CoSb₃ have been studied at room temperature. The Seebeck coefficient decreases with increasing Na content. The electrical resistivity decreases with increasing Na content. In this study, the obtained maximum power factor reaches 8.72 μW·cm^-1·K^-2 when Na content is 40%.