摘要
由于具有复杂的晶体结构和超离子导体行为,金属硫属化合物特别是Cu2-xSe在热电领域得到了广泛的关注.本文报道了一种简单易行的提高热电效率的方法:在基体材料Cu2-xSe中添加纳米Zn Te插层,用来提高Cu2-xSe材料的热电性能.实验结果表明,Cu2-xSe-Zn Te复合材料的电导率提高了32%,电导率的增加牺牲了塞贝克系数,导致复合材料的功率因子稍微低于纯Cu2-xSe基体材料;第二相的引入抑制了晶格热扩散,使得Cu2-xSe-Zn Te复合材料的热导率降低了34%.由此可知,适中的功率因子和较低的热导率致使含有10 wt.%Zn Te的Cu2-xSe-Zn Te复合材料在中温条件(750 K)下的z T值提高至0.40,相比于纯Cu2-xSe基体材料该数值提高了40%.因此,向Cu2-xSe材料中添加纳米Zn Te插层,是提高Cu2-xSe基材料热电性能的一个有效途径.
Metal chalcogenides especially Cu2-x Se has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric efficiency by introducing Zn Te nanoinclusions into the matrix of Cu2-x Se. As a result, a substantial improvement of 32% in electrical conductivity of Cu2-x Se-Zn Te composite is observed. The increase in electrical conductivity is at the expense of Seebeck coefficient, which slightly decreases the power factor of the composite samples than that of pure Cu2-x Se. Furthermore, the introduction of secondary phase facilitates in declining the total thermal conductivity of Cu2-x Se-Zn Te composite up to 34% by suppressing the lattice thermal contributions. Thus, the moderate power factor and lower thermal conductivity values result in an improved figure of merit(z T) value of ~0.40 in mid-range temperature(750 K) for Cu2-x Se-Zn Te composite with 10 wt.% of Zn Te, which is about 40% higher than that of its pure counterpart. Hence, it is believed that the incorporation of Zn Te nanoinclusions in the matrix of Cu2-x Se may be an important route to improve the thermoelectric properties of Cu2-x Se based compounds.
基金
supported by the Chancellor Scholarship funding
