Proton conductivity measurement of the sol-gel derived yttrium-doped SrZrO3 thin films for fuel cell applications

Crystallized yttrium-doped SrZrO₃ thin films were successfully deposited by sol-gel method with annealing temperatures above 600 °C. The conductivity of the derived films was larger than 10^-6 S/cm at 600 °C. In the temperature ranges of 350-400 °C, the ratio of the conductivities in the H₂O and D₂O atmospheres was about 1.4, which suggests the film was proton conductive. In turn, at higher temperatures, the ratio of the conductivities decreased, which means another conductive element, might be oxygen ions, becomes dominant. Though further improvement in conductivity is necessary, we consider this film would bring the lower temperature operations of the SOFCs because it showed proton conductivity below 450 °C.