Work

Two-Dimensional Sodium Fluctuation at High Temperatures in High-Temperature Thermoelectric Material γ-Na0.7CoO2

Year: 2006

Type: article

Abstract: A thermoelectric material, γ-Na 0.7 CoO 2 , with a high figure of merit, Z T >1, at high temperatures has been studied using the atomic pair distribution function (PDF) analysis of pulsed neutron powder diffraction data. We have found significant PDF peak broadening in the correlation between sodium and oxygen atoms at high temperatures. The broad peak indicates that a sodium atom frequently leaves a NaO 6 prism. In other words, sodium atoms hop in a two-dimensional layer at high temperatures. The PDF intensity of the Na–O correlation below a critical length, where a sodium atom is leaving a prism, is inversely proportional to thermal conductivity. This suggests that the short phonon lifetime originates from the frequent sodium hopping in the two-dimensional layer, leading to high-performance thermoelectric generation.

Source: Japanese Journal of Applied Physics

DOI: 10.1143/jjap.45.6395

Authors: Shin-ichi Shamoto, Yuki Hasegawa, Tsuyoshi Kajitani

Institutions: Japan Atomic Energy Agency, Tohoku University

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funders: U.S. Department of Energy, Ministry of Education, Culture, Sports, Science and Technology, Argonne National Laboratory

Awards: G1719812184, G18202666, G1940553382, G2123841078, G6506718449