高压制备CoSbS1-xSex(x=0~0.3)的热电性能

High Pressure Synthesis and Thermoelectric Performance of CoSbS1-xSex(x=0~0.3)

摘要:

副钴锑硫矿（CoSbS）基热电材料，因其组成元素廉价、环境友好等优点，近期受到人们的广泛关注。但由于其具有较高的热导率限制了热电性能，此外，常规方法制备该材料的周期较长，工艺较为繁琐。本文利用一步高压烧结方法制备了CoSbS1-xSex基固溶体合金，测试并分析了其结构和热电性能。结果表明，高压能够加快反应速率，快速制备出单相CoSbS化合物；加入少量Se能够同步优化三个热电参数：即提高Seebeck系数，降低电阻率和热导率。在673 K时，CoSbS0.8Se0.2具有最大的品质因子ZT~0.25，约为母体材料CoSbS的4倍，而且在相同温度条件下高压合成样品的ZT远高于传统方法（固相反应结合放电等离子体烧结）制备CoSbS1-xSex的数值。这些结果表明,高压方法是制备CoSbS基热电材料的一种有效方法。

Abstract:

Paracostibite (CoSbS), as a thermoelectric material, has attracted much attention recently. It has many advantages such as low cost and environment-friendly. However, the thermoelectric performance is limited by the high thermal conductivity. In addition, the preparation of this material need a long-duration heating process and a complicated process by conventional method. In this paper, CoSbS1-xSex based solid solution alloys were facile and rapidly prepared by one-step high pressure method. Their structures and thermoelectric properties were investigated. The results show that high pressure can accelerate the reaction rate and fabricate single-phase CoSbS quickly. Alloying with a small amount of Se can simultaneously optimize three thermoelectric parameters: increasing Seebeck coefficient, reducing resistivity and thermal conductivity. CoSbS0.8Se0.2 has the largest figure of merit ZT~0.25 at 673 K, which is about four times as much as that of the parent material CoSbS. Moreover, the ZT of high-pressure synthesized samples at the same temperature is higher than that of CoSbS1-xSex prepared by the traditional solid-state reaction combined with spark plasma sintering method. These results indicate that high pressure method is an effective method for preparing CoSbS based thermoelectric materials.