The role of oxygen defects on the electro-chemo-mechanical properties of highly defective gadolinium doped ceria.

• Highly defective Gd-doped ceria (GDC) ceramics were sintered at 1450 °C for 10 h. • The Gd-content controls the configuration of oxygen vacancies. • The creep property and strain sensitivity are shown to decrease with Gd. • The electromechanical response is influenced by the ion-blocking barrier effect. In light of the recent discovery of giant electrostriction in defective fluorites, here we investigate the interplay between mechanical, electrochemical and electromechanical properties of oxygen defective ceria compositions (Ce 1−x Gd x O 2−δ) as the effect of Gd-doping (x = 0.05–0.3) at low temperatures. Highly dense polycrystalline ceramics are prepared as micron-size grains with a minimized grain boundary extent. Electrochemical ionic migration by impedance spectroscopy reveals that dopant content controls the oxygen vacancies association in the samples. Interestingly, we observe that electromechanical activity is strongly controlled by the local oxygen vacancy configuration rather than on its nominal concentration. The primary creep at room temperature indicates a declining viscoelastic trend with increasing oxygen defects. [ABSTRACT FROM AUTHOR]