Local electrical and dielectric properties of nanocrystalline yttria-stabilized zirconia

Abstract

Grain core and grain boundary electrical and dielectric properties of nanocrystalline yttria-stabilized zirconia (YSZ) were analyzed using a novel nano-Grain Composite Model (n-GCM). Partially sintered pellets with average grain sizes ranging from 10 to 73 nm were analyzed over a range of temperatures using AC impedance spectroscopy (AC-IS). Local grain core and grain boundary conductivities, grain boundary dielectric constants, and effective grain boundary space charge widths were determined from the fitted circuit parameters. Required grain core dielectric constant data were provided by AC-IS measurements of single crystal YSZ over a range of temperatures. The local grain core conductivity of all the nanocrystalline samples was slightly decreased with respect to that of microcrystalline YSZ. Conversely, the local grain boundary conductivity was enhanced up to an order of magnitude compared to microcrystalline YSZ. At the nanoscale, there was a noticeable increase in local grain boundary dielectric constant versus single crystal values at the same temperature.

Electrical properties of YSZ/Al2O3 composite and YSZ/Al2O3 interface studied by impedance spectroscopy and finite element modelling

“…Dielectric constants of YSZ and Al 2 O 3 were obtained from Ref. [26,27]. Dielectric constant of YSZ grain boundary is the same as its bulk value since the dielectric constant of ZrO 2 is insensitive to its composition [28].…”

1H-NMR measurements of proton mobility in nano-crystalline YSZ

“…[1][2][3][4] Nano-structured cubic YSZ, however, shows an anomalously high conductivity at room temperature if exposed to a wet atmosphere. This has been attributed to proton conduction.…”

Performance of solid oxide fuel cells approaching the two-dimensional limit

“…e d of YDZ as a function of temperature was obtained from the literature. 21 / B is the barrier height of the trap state to which, it is assumed carriers, have been promoted into. We have used the shallowest traps reported in the literature, 1.4 </ B < 3.2 eV below the conduction band, 14 for YDZ to obtain the highest current possible, thereby giving an upper bound for power loss.…”