Novel Perovskite Semiconductor Based on Co/Fe-Codoped LBZY (La0.5Ba0.5 Co0.2Fe0.2Zr0.3Y0.3O3-δ) as an Electrolyte in Ceramic Fuel Cells

Introducing triple-charge (H+/O2-/e(-)) conducting materials is a promising alternative to modify a cathode as an electrolyte in advanced ceramic fuel cells (CFC). Herein, we designed a novel triple-charge conducting perovskite-structured semiconductor Co-0.2/Fe-0.2-codoped La0.5Ba0.5Zr0.3Y0.3O3-delta (CF-LBZY) and used as an electrolyte and an electrode. CF-LBZY perovskite as an electrolyte exhibited high ionic (O2-/H+) conductivity of 0.23 S/cm and achieved a remarkable power density of 656 mW/cm(2) 550 degrees C. X-ray photoelectron spectroscopy (XPS) analysis revealed that the Co/Fe codoping supports the formation of oxygen vacancies at the B-site of a perovskite structure. Besides, using CF-LBZY as a cathode, the fuel cell delivered 150 and 177 mW/cm(2) at 550 degrees C, respectively, where Y-doped BaZrO3 and Sm-doped ceria (SDC) were used as electrolytes. During the fuel-cell operation, H+ injection into the CF-LBZY electrolyte may suppress electronic conduction. Furthermore, the metal-semiconductor junction (Schottky junction) has been proposed by considering the work function and electron affinity to interpret short-circuiting avoidance in our device. The current systematic study indicates that triple-charge conduction in CF-LBZYO(3-delta) has potential to boost the electrochemical performance in advanced low-temperature fuel-cell technology.