Porosity induced thermoelectric performance optimization for antimony telluride
Porosity induced thermoelectric performance optimization for antimony telluride
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碲化锑的孔隙率诱导热电性能优化
DOI：
10.1016/j.ceramint.2018.08.201
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发表时间：
2018-12-01
影响因子：
5.2
通讯作者：
Xiong, Rui
中科院分区：
文献类型：
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作者：
Gu, Yixi;Liu, Xiaowei;Xiong, Rui
通过施加不同的压力和工艺合成了具有不同孔隙率的Sb_2Te_3块体。用正电子湮没谱测量了孔隙缺陷的变化。通过一步或两步调节烧结温度和压力，对材料的孔隙和界面进行剪裁，提高了Seebeck系数，同时保持了高的电导率，显著降低了热导率。在523 K时，10 kN下两步压制的Sb_2Te_3样品的ZT最大值为1.17，比1 kN下的相应样品提高了54.1%。采用改进的BET模型结合有效介质理论计算的晶格热导率与实验数据吻合较好，揭示了孔隙率调控对降低晶格热导率的重要作用。
Sb2Te3 bulks with various porosities are synthesized via applying different pressures and processes. Pores defect variations are demonstrated by positron annihilation spectroscopy measurement. Through tuning sintering temperature and pressure exerted in one step or two steps, pores and interfaces of the materials are tailored, which enhances the Seebeck coefficient, simultaneously maintains high electrical conductivity and remarkably reduces thermal conductivity. A maximum ZT of 1.17 is obtained at 523 K for Sb2Te3 samples compacted in two steps under 10 kN, increasing by 54.1% as compared to corresponding sample under 1 kN. Lattice thermal conductivity calculation by modified BET model combining with effective medium theory fits with experiments data, revealing porosity manipulation plays a significant role in reducing thermal conductivity.