Influence of Sc concentration on transport properties of CaHf1-xScxO3-α

In this work, a series of CaHf1-xScxO3-alpha (x = 0, 0.10, 0.15, 0.20, and 0.30) perovskite oxides have been prepared by a solid-state reaction. The crystal structure and lattice parameters of the orthogonally-distorted perovskite phases of CaHf1-xScxO3-alpha were obtained. The results revealed that Sc-doping could significantly improve the conductivity and proton transport properties of CaHfO3. However, at x > 0.2, the conductivity decreased with increase in Sc concentration. CaHf0.85Sc0.15O3-alpha exhibited the highest conductivity among all specimens in the temperature range of 400 to 900 degrees C. The conduction activation energy of CaHfO3 significantly decreased with Sc-doping in the range of 0.66 to 1.52 eV. Overall, the CaHf1-xScxO3-alpha demonstrated pure proton conduction in the temperature range of 300 to 600 degrees C under wet 1%H-2-Ar, whereas the proton relative transport number decreased with increasing temperature to within the range of 600-900 degrees C. At an optimal Sc concentration of x = 0.1, CaHf1-xScxO3-alpha rendered the highest proton transport number.

Automated summary

In this study, a series of CaHf1-xScxO3-alpha perovskite oxides were prepared by solid-state reaction, showing improved conductivity and proton transport properties with Sc-doping. However, conductivity decreased at x > 0.2, and CaHf0.85Sc0.15O3-alpha exhibited the highest conductivity. The conduction activation energy of CaHfO3 significantly decreased with Sc-doping between 0.66 to 1.52 eV.