Impact of dopants on electrical conductivity of proton-conducting SrHfO3 perovskite.

For reliable long-term operation of solid oxide electrochemical devices for the hydrogen energy system, an electrolyte with high ionic conductivity and excellent chemical stability is required. SrHfO 3 -based perovskites are known for their high chemical resistance; however, their ionic conductivity must be increased. In the present research, the effect of doping with yttrium and ytterbium on the electrical properties of strontium hafnate was studied for the first time. The crystal structure, solubility limit of the dopants, morphology and electrical properties of SrHf 1-x M x O 3-δ (M = Y, Yb) materials were investigated by the X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, direct current four-probe technique, and impedance spectroscopy. The solubility limits of Y and Yb in SrHfO 3 were found to lie slightly below x = 0.10. It was revealed that yttrium doping is more favorable for the grain growth and densification of ceramics. A comparative analysis of the influence of dopant type (Y, Yb and Sc) and concentration on the electrical properties of SrHfO 3 is provided. [Display omitted] • Homogeneity range of SrHf 1-x Y x O 3-δ and SrHf 1-x Yb x O 3-δ solid solutions extends to x ≈< 0.10. • Y-doping is more favorable for the grain growth and densification of ceramics. • Y and Yb-doping enhance proton conductivity of SrHfO 3. • Y-doped SrHfO 3 has higher ionic transference numbers in wet oxidizing atmospheres. [ABSTRACT FROM AUTHOR]