Features of electrical transport and H/D isotope effects in the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

The electrical properties of the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-delta were studied using the 4probe direct current (DC) method depending on temperature and oxygen partial pressure in the atmospheres, humidified with H2O and D2O. Ionic and electron hole contributions to the electrical conductivity were determined, and the transport numbers of charge carriers were calculated. It is shown that in air conditions BaCe0.7Zr0.1Y0.1Yb0.1O3-delta is a mixed ion-electron hole conductor. The contribution of electron hole conductivity decreases with the decrease of temperature and oxygen partial pressure. A significant isotope H/D effect in the electrical conductivity is observed for all investigated conditions expressed in the decrease in conductivity in D2O-containing atmospheres with the increase of activation energy values. Replacing H2O with D2O leads to decrease in the ion transport numbers and ionic conductivity values, while the electron hole conductivity remains almost the same.