Protonic Conduction in Y-, Yb- and Sc-Doped SrZrO3 Ceramics

Abstract

AbstractProtonic conduction of SrZrO3 doped with Y3+(5%), yb3+(5 and 10%) and Sc3+(5, 10, 15 and 20%) has been investigated in a frozen-in condition at 20-400°C following a high-temperature pre-treatment in water vapor. Water uptake was also determined gravimetrically. The pure sample shows no proton incorporation and relatively low conductivity. The oxygen partial pressure dependence of conductivity under dry atmosphere shows hole conduction only when P(O2) >10−5 atm. All of the doped samples show good protonic conduction and a non-classical H2O/D2O isotope effect. The conductivity and water uptake is always higher for samples slowly cooled from the pre-treatment than for quenched samples. The activation energy, as well as the pre-exponentials, of the slowly cooled samples consistently suggest Stage II behavior, with an activation energy for proton migration of 0.61±0.02eV and an effective proton concentration close to the actual concentration. It is concluded that SrZrO3 deserves serious consideration as a proton electrolyte.