Low temperature operating micro solid oxide fuel cells with perovskite type proton conductors

We fabricated micro solid oxide fuel cells with perovskite type proton conductors on silicon substrates, and evaluated their electrical properties using electrochemical impedance spectroscopy (EIS). The cells with 15 mol% yttrium-doped BaZrO ₃ and Pt-Pd electrodes could resist several thermal cycles from room temperature to 317°C, and they showed sufficient open circuit voltage over 1 V around 300°C, if physical gas leakage was properly prevented. Maximum power density of cells reached 8.4 mW/cm at 270°C. This value was quite promising for low temperature operation. But, the results of power generation test were so different from each other and difference was sometimes over two orders of magnitude. EIS results indicated the contribution of electrolyte resistance to total resistance was small and those differences were due to the difference of electrode reaction components.