銅摻雜與二氧化矽氣凝膠添加之鉍-銻-鍗奈米複合材料熱電特性研究

Thermoelectric Properties of Bi-Sb-Te Based Nanocomposites with Copper Nanoparticles Decoration and Silica Aerogel Inclusion

藍天蔚(Tian-Wey Lan)

指導教授 ： 陳洋元

共同指導教授 ： 李定國(Ting-Kuo Lee)

國立臺灣大學/理學院/物理學研究所/博士(2016年)

https://doi.org/10.6342/NTU201603536

摘要

無資料

關鍵字

熱電材料 ； 奈米複合材 ； 奈米顆粒 ； 氣凝膠

並列摘要

In the past decade, thermoelectricity attracts much attention and plays a viable role in renewable energy development due to its characteristic of heat-electricity conversion. The efficiency of energy conversion of thermoelectric (TE) material is a main challenge for practical application, therefore, seeking new methodology to improve the TE material energy conversion efficiency is an important research topic.
Bi2Te3 based materials and their alloys are the most promising commercial TE materials ever found for the application near room temperature. In this report, thermoelectric properties of Bi-Sb-Te based nanocomposites with copper nanoparticles decoration and silica aerogel inclusion have been studied. In the first part, the copper nanoparticles decorated p-type CuxBi0.5Sb1.5Te3 nanocomposites were obtained from the sintering by park plasma sintering (SPS) of Cu nanoparticles and BST powders. A high figure of merit (zT) performance in the Cu-decorated Bi0.5Sb1.5Te3 system achieves a peak zT value of ~1.31 in the Cu0.01Bi0.5Sb1.5Te3 specimen at 420 K. The zT values of bulk samples were significantly enhanced by 30% as compared to their pristine Bi-Sb-Te ingot (zT =0.8~1.0 at 340 K). In general, an average high figure of merit (ZTave) over a wide temperature range is a new criterion for practical application. For Cu0.01Bi0.5Sb1.5Te3 specimen, a ZTave=1.14 spanning a broad temperature range of 300-500 K is achieved, which is one of highest level of Bi2Te3 based compounds ever reported. Our results suggest this copper nano-particle decoration can be an effective approach for the production of TE materials with improved zT.
In the secondary part, reducing the thermal conductivity while preserving the power factor is another alternative way to enhance the zT of materials. Here we discovered that Bi0.5Sb1.5Te3 composites incorporated with ~30 vol.% (3.3 wt.%) silica aerogel reach a high zT value of ~1.45 at 350 K. The silica aerogel is a material having extremely high porosity and low thermal conductivity due to its mesoporous nanostructure. Mixing the Bi0.5Sb1.5Te3 matrix with appropriate silica aerogels only slightly decreases the Seebeck coefficient, but doesn’t deteriorate the electrical conductivity. The power factor of the composites can be maintained as high as the pristine one as the thermal conductivity of silica aerogel composites is significantly reduced. As a consequence, the highest zT value is achieved.
In conclusion, we show two different strategies to achieve higher zT. These techniques provide a possible method to improve zT for the existing TE materials.

並列關鍵字

thermoelectric material ； nanocomposite ； nanoparticle ； aerogel

參考文獻

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