Enhancement of thermoelectric properties in Sr0.7Ba0.3Nb2O6−δ-based ceramics via nano-sized Ti as additive

IF 2.7 3区物理与天体物理 Q2 PHYSICS, APPLIED

Journal of Applied Physics Pub Date : 2024-01-11 DOI:10.1063/5.0177326

Min Zhu, Nan Zhang, Dandan Ma, Xiaobin Yan, Faqi Zhan, Yuehong Zheng, Xuefeng Lu, Peiqing La

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引用次数: 0

Abstract

A series of Sr0.7Ba0.3Nb2O6−δ/x wt. % Ti (x = 1, 3, 5, and 10) composite ceramic thermoelectric materials were prepared, and the mechanism for improving their thermoelectric properties was explored. The experimental results demonstrate that nano-additive titanium powder undergoes oxidation to form TiO2 during sintering. However, under annealing in a reducing atmosphere, oxidation reactions further deplete the lattice oxygen, leading to an increased generation of oxygen vacancies and enhanced carrier concentration, ultimately leading to successful resistivity reduction. The samples consistently exhibit low thermal conductivity values below 2.0 W m−1 K−1 due to crystal defects, complex structure, and phonon scattering at the grain boundaries. The sample doped with 5 wt. %. Ti exhibits the lowest resistivity and highest PF value (409.3 μW/m K2 at 1073 K). Consequently, the figure of merit of Sr0.7Ba0.3Nb2O6−δ with 5 wt. % Ti attains its maximum value of 0.30 at 1073 K, representing a 50% increase compared to that of the undoped sample Sr0.7Ba0.3Nb2O6−δ (0.20 at 1073 K).

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以纳米级 Ti 为添加剂增强 Sr0.7Ba0.3Nb2O6-δ 基陶瓷的热电特性

制备了一系列 Sr0.7Ba0.3Nb2O6-δ/x wt. % Ti（x = 1、3、5 和 10）复合陶瓷热电材料，并探索了改善其热电特性的机理。实验结果表明，纳米添加剂钛粉在烧结过程中会氧化形成 TiO2。然而，在还原气氛中退火时，氧化反应会进一步耗尽晶格中的氧，导致氧空位生成增加，载流子浓度提高，最终成功降低电阻率。由于晶体缺陷、结构复杂以及晶界的声子散射，样品的热导率始终低于 2.0 W m-1 K-1。掺杂 5 wt.钛的样品电阻率最低，PF 值最高（1073 K 时为 409.3 μW/m K2）。因此，掺有 5 wt. % Ti 的 Sr0.7Ba0.3Nb2O6-δ 的优点值在 1073 K 时达到最大值 0.30，比未掺杂的样品 Sr0.7Ba0.3Nb2O6-δ 的优点值（1073 K 时为 0.20）增加了 50%。

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来源期刊

Journal of Applied Physics 物理-物理：应用

CiteScore

5.40

自引率

9.40%

发文量

1534

审稿时长

2.3 months

期刊介绍： The Journal of Applied Physics (JAP) is an influential international journal publishing significant new experimental and theoretical results of applied physics research. Topics covered in JAP are diverse and reflect the most current applied physics research, including: Dielectrics, ferroelectrics, and multiferroics- Electrical discharges, plasmas, and plasma-surface interactions- Emerging, interdisciplinary, and other fields of applied physics- Magnetism, spintronics, and superconductivity- Organic-Inorganic systems, including organic electronics- Photonics, plasmonics, photovoltaics, lasers, optical materials, and phenomena- Physics of devices and sensors- Physics of materials, including electrical, thermal, mechanical and other properties- Physics of matter under extreme conditions- Physics of nanoscale and low-dimensional systems, including atomic and quantum phenomena- Physics of semiconductors- Soft matter, fluids, and biophysics- Thin films, interfaces, and surfaces