High thermoelectric performance of superionic argyrodite compound Ag8SnSe6

Lin Li, Yuan Liu, Jiyan Dai, Aijun Hong, Min Zeng, Zhibo Yan, Jun Xu, Dong Zhang, Dan Shan, Shilei Liu, Zhifeng Ren, Jun Ming Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

55 Citations (Scopus)

Abstract

A good thermoelectric material usually has a high power factor and low thermal conductivity for high figure of merit (ZT), and is also environmentally friendly and economical. Superionic compounds are heavily studied because of their ultra-low thermal conductivity even though the thermal stability remains an issue. In this work, we report a superionic argyrodite compound Ag8SnSe6as a promising mid-temperature thermoelectric material because of its high ZT and good thermal stability up to 550 °C. It is revealed that Ag8SnSe6exhibits a decent Seebeck coefficient (n-type) and electrical conductivity. At the same time, its thermal conductivity is lower than the glass limit with the thermal capacity CVbelow 3NkBat high temperature, where N is the Avogadro's number and kBthe Boltzmann constant. Detailed microstructural and thermodynamic characterization of this compound is performed to understand the electronic and phononic origins of the thermoelectric properties. The highly random ionic occupations in the cubic phase, leading to the molten silver sublattice and phononic mode softening, are responsible for the very low thermal conductivity and ZT ∼ 1.1 at 450 °C.
Original languageEnglish
Pages (from-to)5806-5813
Number of pages8
JournalJournal of Materials Chemistry C
Volume4
Issue number24
DOIs
Publication statusPublished - 1 Jan 2016

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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