Measurements of the electronic conductivities of In-doped CaZrO3 by a DC polarization technique

The following hydrogen and oxygen concentration cells using the oxide protonic conductors, CaZr0 98In0 02O3-delta and CaZr0 9In0 1O3-delta, as the solid electrolyte were constructed, and their polarization behavior was studied, (reversible -)Pt, H-2+H2O/CaZn1-nu InyO3-delta(y = 0 02or0 1)/Ar(+H-2 + O-2), Pt(+ irreversible) The characteristics between applied voltages and external currents (V-I characteristics) in a DC polarization state were studied at 1,173 to 1,273 K in various atmospheres at the side of the reversible electrode From the obtained atmosphere dependence of the steady-state current, the solubilities of protons in In-doped CaZrO3 were evaluated based on the appropriate defect model The solubility of protons was found to decrease with increasing indium concentration in the matrix The standard free energy of proton dissolution into In-doped CaZrO3 of the composition CaZr0 98In0 02O3-delta was estimated to be as follows H2O+V-o(center dot center dot)+O-o(x) = 2OH(o)(center dot) Delta G degrees (kJ/mol) = -194(kJ/mol) + 0 166(kJ/molK)T +/- 5kJ/mol and that of the composition CaZr0 9In0 1O3-delta could not be determined accurately