Degradation mechanism of scandia-stabilised zirconia electrolytes: Discussion based on annealing effects on mechanical strength, ionic conductivity, and Raman spectrum

Enthalpies of formation in the scandia‐zirconia system

“…The highest ionic conductivity is, however, found for cubic fluorite structure, which is only achieved at high temperatures (close to 600°C) also in the 8–12 mol% range due to the β‐ c reversible phase transition . Even when the cubic phase is obtained, a degradation of its ionic conductivity occurs in SOFC operating conditions due to the spontaneous phase transitions …”

“…The cubic fluorite phase stabilization and long‐term stability have been the focus of several researches in the past years . According to literature, the precipitation of secondary phases as function of time is a detrimental factor for ionic conductivity.…”

“…According to literature, the precipitation of secondary phases as function of time is a detrimental factor for ionic conductivity. Whereas the formation of tetragonal phases in cubic matrix takes place for compositions lower than 10 mol% Sc 2 O 3 , rhombohedral phase precipitation usually occurs above 10 mol% . Thereby, this combination of difficulty of cubic phase stabilization and degradation of the ionic conductivity prevent ScZ system application as a commercial solid electrolyte.…”

“…7 Even when the cubic phase is obtained, a degradation of its ionic conductivity occurs in SOFC operating conditions due to the spontaneous phase transitions. [7][8][9] The cubic fluorite phase stabilization and long-term stability have been the focus of several researches in the past years. 1,[7][8][9][10] According to literature, the precipitation of secondary phases as function of time is a detrimental factor for ionic conductivity.…”

Layered YSZ/SCSZ/YSZ Electrolytes for Intermediate Temperature SOFC Part I: Design and Manufacturing

“…But such conductivity is not sufficient for the electrolyte-supported SOFC, where the electrolyte thicknesses are on the order of 100-300 lm. In addition to high ionic conductivity, the mechanical performance of SSZ is slightly higher than that of YSZ if processed properly [15][16][17][18]. Sc 2 O 3 doped ZrO 2 (SSZ) is considered as an alternative to YSZ ceramics.…”