Enhancement of Thermoelectric Performance of Sr0.9La0.1TiO3-Based Ceramics Regulated by Nanostructures

Mengjie Qin; Zhihao Lou; Ping Zhang; Zongmo Shi; Jie Xu; Yongsheng Chen; Feng Gao

doi:10.1021/acsami.0c13693

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures

ACS Appl Mater Interfaces. 2020 Dec 2;12(48):53899-53909. doi: 10.1021/acsami.0c13693. Epub 2020 Nov 18.

Authors

Mengjie Qin¹, Zhihao Lou¹, Ping Zhang¹, Zongmo Shi¹, Jie Xu^{1

2}, Yongsheng Chen³, Feng Gao¹

Affiliations

¹ State Key Laboratory of Solidification Processing, MIIT Key Laboratory of Radiation Detection Materials and Devices, USI Institute of Intelligence Materials and Structure, NPU-QMUL Joint Research Institute of Advanced Materials and Structure, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
² Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, China.
³ Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin N.T. 999077, Hong Kong SAR, China.

PMID: 33207864
DOI: 10.1021/acsami.0c13693

Abstract

La-doped strontium titanite (Sr_0.9La_0.1TiO₃) is a promising candidate for n-type oxide thermoelectric materials. However, the ZT values of this material are low, leading to low conversion efficiency. Improvements in this efficiency are required. In this work, a high ZT value of 0.50 was obtained for Sr_0.9La_0.1TiO₃ ceramic samples by adding 10 wt % Bi₂O₃ sintering aids and 20 wt % nanosized Ti powders to the matrix material. Although Ti was oxidized to TiO₂ during the sintering process, nanoscale phase interfaces were beneficial for phonon scattering and thermal conductivity reduction. Nanosized metallic Bi and Bi₂O₃ particles were observed. These two factors played an important role in reducing the thermal conductivity from 2.5 W/(m K) at room temperature to 1.31 W/(m K) at 1073 K. Nanostructure control using nanosized metal powders as additives combined with the Bi₂O₃ sintering aid paves a way for enhancement of thermoelectric properties of oxide thermoelectric materials.

Keywords: Sr0.9La0.1TiO3; additive; nanostructure; sintering aid; thermal conductivity.