Synthesis and characterization of BaZr0.8y0.2O 3 protonic conductor for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs)

Barium zirconate BaZr_0.8Y_0.2O_3-δ to be used as protonic conductor under hydrogen containing atmosphere in intermediate temperature (500-700°C) solid oxide fuel cells (IT-SOFCs) was prepared using a sol-gel technique to produce materials with controlled chemical structure and microstructural properties. Several synthetic procedures were investigated, dissolving the metal cations in two solvents (water and ethylene glycol) and using different molar ratios of citric acid with respect to the total metal content. A single phase was obtained at temperature as low as 1100°C. To verify the chemical stability, all the sintered oxides were exposed to CO₂ and the phase composition of the resulting specimens was investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). Fuel cell polarization curves on symmetric Pt/BZY20/Pt cells of different thickness were measured at intermediate temperatures (500-700°C).