Thermoelectric Oxides and Neutron ScatteringV

by Dr Zhilun Lu (University of Sheffield)

Thursday 3 Jan 2019, 14:00 → 15:30 Asia/Shanghai

TDLI Meeting Room 200

Abstract

Most state-of-the-art thermoelectrics with high Figures of Merit values are composed of toxic, naturally rare and heavy metal elements. As a result, further work is required to develop new, low-cost, stable materials based on oxides. Excellent properties for p-type oxides have already been reported. However, n-type oxides with equivalent ZT values have yet to be discovered to date. SrTiO3-based systems have attracted considerable attention due to their high thermoelectric properties by so-called donor-doping with higher valence ions on the A- or B-site, especially lanthanum-doped SrTiO3 (LST). In this talk, I will introduce a successful strategy by creating A- site and O deficiency in the perovskite structure to improve the thermoelectric performance by reducing thermal conductivity and increasing the electrical conductivity, simultaneously. Then, the highest ZT value reported for n-type SrTiO3 based ceramics has been achieved.

Neutron scattering is 'an excellent probe' to study the structure and dynamic properties of materials. Inelastic neutron scattering probes the atomic and molecular motion, magnetic, and lattice excitations of materials by measuring changes in the neutron momentum and energy simultaneously. For thermoelectric materials, low intrinsic thermal conductivity is an asset for enhanced thermoelectric performance. Numerical modelling of phonon lifetimes is an important ingredient to predict novel high-performance thermoelectric materials. Therefore, experimental data on phonon lifetimes is required which allows to test the predictive power of numerical calculations. We have used inelastic neutron scattering techniques to measure phonon lifetimes in the SrTiO3 which is known to offer good thermoelectric properties. The triple axis spectroscopy experiments convincingly demonstrate the anisotropy of phonon lifetimes along different crystallographic directions.

Biography

教育与工作背景

2018.09~             英国亨利劳斯研究所谢菲尔德所  材料科学与工程  博士后

2016.03~2018.08   德国柏林赫姆霍兹能源与材料研究中心  博士后

2011.10~2016.01   英国谢菲尔德大学（世界 100 强）材料科学与工程 工学博士

2008.09~2010.12   中南大学（985 工程）  材料物理   工学硕士

2004.09~2008.06   中南大学（985 工程）  材料物理   工学学士

研 究 方 向 与 审 稿 服 务

中子散射：高温超导，液态量子自旋，磁性，热电等材料的非弹性中子散射，中子共振自旋回波谱同步辐射：铁电，压电材料在电场下的微观结构测量功能材料：热电材料，巨介电材料，压电材料，微波陶瓷，锂离子电池金属材料：高温铝合金，高强铝合金曾审稿杂志：Physical Review Letters，journal of alloys and compounds，Materials Letters，等等

Division

Condensed Matter