Protonic conductivity of nano-structured yttria-stabilized zirconia: dependence on grain size

Abstract

The conductivity of dense ceramics of nanocrystalline yttria-stabilized zirconia (nano-YSZ), with average grain sizes ranging from 13 nm to 100 nm, was measured in wet and dry air as a function of temperature between 30 C and 500 C. Under wet conditions (p H 2 O ¼ 2.3 Â 10 À2 atm) the measured conductivity at low temperatures (<150 C) was found to increase strongly with decreasing grain size, displaying a highly non-linear dependence on grain size. This is interpreted as evidence of the protonic conductivity of grain boundaries increasing with decreasing grain size.

Oxygen Isotope Transport Properties of Yttria‐Stabilized Zirconia (YSZ) in O2‐ and H2O‐Containing Atmospheres

“…Thus, we confirm earlier results [12,14,16] that YSZ remains an excellent oxygen-ion conductor, even at high pH 2 O. …”

“…The concentration of incorporated protons, however, is small compared with the concentration of oxygen vacancies (the equilibrium is on the left hand side even at high pH 2 O [14,15]), and YSZ remains an excellent oxygen-ion conductor under such conditions [14,16].…”

Low-temperature performance of yttria-stabilized zirconia prepared by atomic layer deposition

“…We suspect that this is a result of the crossplane measurements being taken across the ALD YSZ columns, which offers little possibility of measuring the conduction through intergranular regions or across grain boundaries. This explanation is supported by previous studies on nanogranular YSZ, measured in a similar temperature regime [19,20].…”

Ionic properties of ultrathin yttria-stabilized zirconia thin films fabricated by atomic layer deposition with water, oxygen, and ozone

“…Recent studies have revealed enhanced proton transport in nano-granular YSZ [9][10][11][13][14][15][16][17][18]; this is due to the high population of vacancies on the grain surface for compensation of space charge potentials in the vicinity of grain boundary regions [19]. Hence, water or hydroxyl groups preferentially adsorb or chemisorb onto the grain surface, which lead to high concentration of protons in nano-granular YSZ compared to micro-granular materials [13][14][15]17,18]. In this respect, it is reasonable that a substantial amount of protons are incorporated into ALD YSZ films comprised of nanoscale grains [9][10][11].…”