Mixed dopant effect in SrZrO3-based proton conductor

The infrared diffuse reflectance spectra in the O-H stretching vibration, v(OH), region and the electrical conductivities of Sr(Zr0.92Y0.08-xScx)O3-delta and Sr(Zr0.92Y0.08-xGax)O3-delta were studied. Whereas the dissolution environment of the proton and the dopant in the terminal compounds was maintained in the Sr(Zr0.92Y0.08-xScx)O3-delta, distinctly different proton sites from those intheterminal Sr(Zr0.92Y0.08)O3-delta and Sr(Zr0.92Ga0.08)O3-delta appeared in the Sr (Zr0.92Y0.08-xGax)O3-delta. The electrical conductivity of the Sr(Zr0.92Y0.08-xScx)O3-delta showed a very small increase upon substitution of Y by Sc. The small increase in conductivity for the Sc-doped case was discussed from the viewpoint of proton mobility. For the Sr(Zr0.92Y0.08-xGax)O3-delta, the conductivity decreased over an order of magnitude by the substitution of Y by Ga. This decrease in conductivity for the Ga-doped case was attributed to the decrease in the proton concentration. (c) 2008 Elsevier B.V. All rights reserved.