A Promising Proton Conducting Electrolyte BaZr(1-x)Ho(x)O(3-δ) (0.05 ≤ x ≤ 0.20) Ceramics for Intermediate Temperature Solid Oxide Fuel Cells

In this study, the Ho-substituted BaZrO(3) electrolyte ceramics (BaZr(1-x)Ho(x)O(3-δ), 0.05 ≤ x ≤ 0.20) were synthesized through a low-cost flash pyrolysis process followed by conventional sintering. The effects of Ho-substitution in BaZrO(3) studied in terms of the structural phase relationship, microstructure and electrical conductivity to substantiate augmented total electrical conductivity for intermediate temperature solid oxide fuel cells (IT-SOFCs). The Rietveld refined X-ray diffraction (XRD) patterns revealed that pure phase with [Formula: see text] space group symmetry of cubic crystal system as originated in all samples sintered at 1600 °C for 8 h. The Raman spectroscopic investigations also approved that Ho incorporation in BaZrO(3) ceramics. Field Emission Scanning Microscopic (FESEM) study informed a mixture of fine and coarse grains in the fracture surface of Ho-substituted BaZrO(3) sintered samples. The relative density and average grain size of samples were observed to decrease as per the addition of Ho-substitution in BaZrO(3) ceramics. The electrical conductivity study was accomplished by Electrical Impedance Spectroscopy (EIS) under 3% humidified O(2) atmosphere from 300 to 800 °C. Furthermore, the total electrical conductivity of BaZr(0.8)Ho(0.2)O(3-δ) ceramic was found to be 5.8 × 10(−3) S-cm(−1) at 600 °C under 3% humidified atmosphere, which may be a promising electrolyte for IT-SOFCs.