Ag₉GaSe₆: high-pressure-induced Ag migration causes thermoelectric performance irreproducibility and elimination of such instability.

ABSTRACT: The argyrodite Ag₉GaSe₆ is a newly recognized high-efficiency thermoelectric material with an ultralow thermal conductivity; however, liquid-like Ag atoms are believed to cause poor stability and performance irreproducibility, which was evidenced even after the 1^st measurement run. Herein, we demonstrate the abovementioned instability and irreproducibility are caused by standard thermoelectric sample hot-pressing procedure, during which high pressure promotes the 3-fold-coordinated Ag atoms migrate to 4-fold-coordinated sites with higher-chemical potentials. Such instability can be eliminated by a simple annealing treatment, driving the metastable Ag atoms back to the original sites with lower-chemical potentials as revealed by the valence band X-ray photoe

SUBMITTER: Liu JY 

PROVIDER: S-EPMC9142491 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature