Retarding Ostwald ripening through Gibbs adsorption and interfacial complexions leads to high-performance SnTe thermoelectrics

Decheng An, Jiangjing Wang, Jie Zhang, Xin Zhai, Zepeng Kang, Wenhao Fan, Jian Yan, Yequn Liu, Lu Lu, Chun Lin Jia, Matthias Wuttig, Oana Cojocaru-Mirédin, Shaoping Chen*, Wenxian Wang, G. Jeffrey Snyder, Yuan Yu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Nanoprecipitation is a routine method to decrease the thermal conductivity for advancing thermoelectric performance. However, the coarsening/Ostwald ripening of precipitates under temperature gradients in long-duration service deteriorates the efficacy of this strategy. Enlightened by the Gibbs adsorption-induced suppression of Ostwald ripening, we designed a highly stable thermoelectric system SnAg0.05Te-x%CdSe with embedded novel core/shell nanoprecipitates. Scanning transmission electron microscopy and atom probe tomography reveal that the precipitate core is CdTe and the shell is formed by Ag segregation with structures and compositions different from its abutting phases, termed interfacial complexions. This complexions layer suppresses the coarsening of precipitates by decreasing the interfacial Gibbs free energy, resulting in a high number of nanoscale precipitates. The enlarged phonon scattering cross-section of nanoprecipitates enabled by Gibbs adsorption along with interfacial complexions restrains the lattice thermal conductivity to its minimum while maintaining high carrier mobility. This eventually leads to an outstanding figure-of-merit (zT) of 1.5 at 873 K in thermally aged SnAg0.05Te-6%CdSe, assisted with valence band flattening and convergence. This work explores the mechanisms underpinning precipitate stabilization and provides a new paradigm to design nanostructured thermoelectrics.

Original languageEnglish (US)
Pages (from-to)5469-5479
Number of pages11
JournalEnergy and Environmental Science
Volume14
Issue number10
DOIs
StatePublished - Oct 2021

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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