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

Abstract

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 Co0.2/Fe0.2-codoped La0.5Ba0.5Zr0.3Y0.3O3-δ (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/cm2 550 °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/cm2 at 550 °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-LBZYO3-δ has potential to boost the electrochemical performance in advanced low-temperature fuel-cell technology.