TY - JOUR
T1 - Nature and strength of defect interactions in cubic stabilized zirconia
AU - Bogicevic, A.
AU - Wolverton, C.
PY - 2003/1/17
Y1 - 2003/1/17
N2 - The intrinsic ordering tendencies that limit ionic conduction in doped zirconia electrolytes are fully elucidated using first-principles calculations. A detailed analysis of nearly 300 yttria- and scandia-stabilized cubic-zirconia-ordered vacancy compounds reveals a delicate balance between competing elastic and electrostatic interactions. These results explain several outstanding experimental observations and provide substantial insight needed for improving ionic conduction and enabling low-temperature operation of zirconia-based electrolytes. We show that the surprising (formula presented) vacancy ordering in dilute solid solutions is a consequence of repulsive electrostatic and attractive elastic interactions that balance at third-neighbor vacancy separations. In contrast, repulsive elastic vacancy-dopant interactions prevail over electrostatic attraction at all probed defect separations in YSZ and lead to very weak ordering preferences in ScSZ. The total electronic contribution to the defect interactions is shown to be strongly dominated by simple point-charge electrostatics, leaving speciation of defect ordering for a given class of aliovalent dopants to the elastic term. Thus, ion size becomes a critical parameter in controlling the ionic conductivity of doped oxide electrolytes.
AB - The intrinsic ordering tendencies that limit ionic conduction in doped zirconia electrolytes are fully elucidated using first-principles calculations. A detailed analysis of nearly 300 yttria- and scandia-stabilized cubic-zirconia-ordered vacancy compounds reveals a delicate balance between competing elastic and electrostatic interactions. These results explain several outstanding experimental observations and provide substantial insight needed for improving ionic conduction and enabling low-temperature operation of zirconia-based electrolytes. We show that the surprising (formula presented) vacancy ordering in dilute solid solutions is a consequence of repulsive electrostatic and attractive elastic interactions that balance at third-neighbor vacancy separations. In contrast, repulsive elastic vacancy-dopant interactions prevail over electrostatic attraction at all probed defect separations in YSZ and lead to very weak ordering preferences in ScSZ. The total electronic contribution to the defect interactions is shown to be strongly dominated by simple point-charge electrostatics, leaving speciation of defect ordering for a given class of aliovalent dopants to the elastic term. Thus, ion size becomes a critical parameter in controlling the ionic conductivity of doped oxide electrolytes.
UR - http://www.scopus.com/inward/record.url?scp=6444234833&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=6444234833&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.67.024106
DO - 10.1103/PhysRevB.67.024106
M3 - Article
AN - SCOPUS:6444234833
SN - 1098-0121
VL - 67
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 2
ER -