采用水热法合成Bi2Te3粉体,将炭黑(CB)与其掺杂制备不同比例的碲化铋/炭黑(Bi2Te3/CB)复合材料,研究复合材料的热电性能.同时采用TGA、SEM、XRD等分析方法表征Bi2Te3/CB复合材料的结构,探究微观结构与热电性能的关系.研究发现:室温下,CB的引入使Bi2Te3/CB复合材料的热导率大大降低(0.5957 W/(m·K)降到0.0888 W/(m·K));随着Bi2Te3含量的增加,复合材料的电导率、热导率均增大,Seebeck系数先增加后降低;当Bi2Te3含量为88.9%时,在558℃烧结10 min所得的Bi2Te3/CB复合材料室温下热电优值ZT最大(ZT=0.21).虽然ZT值未能达到应用价值,但是CB的添加为改善Bi2Te3材料的热电性能,尤其在降低材料的热导率方面,提供了新方法和新思路.
Bi2Te3 powders were successfully synthesized by hydrothermal reaction,which were composited with carbon black (CB),and then the thermoelectric (TE) performance of Bi2Te3/CB composites was investigated.At the same time,TGA,SEM and XRD analysis methods were used to characterize the structure of Bi2Te3/CB composites and the relationship between microscopic structures and TE properties was researched intensively.It shows that the thermal conductivities of Bi2Te3/CB composites reduce sharply (from 0.5957 W/(m·K) to 0.0888 W/(m·K) at room temperature) because of doped with CB under the special structure design.However,the values of electrical and thermal conductivities of Bi2Te3/CB composites improve with the increase of Bi2Te3 weight fraction,and Seebeck coefficients increase first and then decrease.After sintering under 558℃ for 10 min,the figure of merit (ZT) of Bi2Te3/CB composites with 88.9% Bi2Te3 is the best (ZT =0.21) at room temperature.Although the ZT value is much lower than the stand of TE material application,this topic investigation may provide new insights and optimization approach into the design and development of Bi2Te3 TE material for application,especially in terms of lower thermal conductivity of materials.
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