Achieving fast ionic conductivity in the electrolyte at low operating temperatures while maintaining the stable and high electrochemical performance of solid oxide fuel cells (SOFCs) is challenging. Herein, we propose a new type of electrolyte based on perovskite Sr0.5Pr0.5Fe0.4Ti0.6O3−δ for low-temperature SOFCs. The ionic conducting behavior of the electrolyte is modulated using Mg doping, and three different Sr0.5Pr0.5Fe0.4–x Mg x Ti0.6O3−δ (x = 0, 0.1, and 0.2) samples are prepared. The synthesized Sr0.5Pr0.5Fe0.2Mg0.2Ti0.6O3−δ (SPFMg0.2T) proved to be an optimal electrolyte material, exhibiting a high ionic conductivity of 0.133 S cm–1 along with an attractive fuel cell performance of 0.83 W cm–2 at 520 °C. We proved that a proper amount of Mg doping (20%) contributes to the creation of an adequate number of oxygen vacancies, which facilitates the fast transport of the oxide ions. Considering its rapid oxide ion transport, the prepared SPFMg0.2T presented heterostructure characteristics in the form of an insulating core and superionic conduction via surface layers. In addition, the effect of Mg doping is intensively investigated to tune the band structure for the transport of charged species. Meanwhile, the concept of energy band alignment is employed to interpret the working principle of the proposed electrolyte. Moreover, the density functional theory is utilized to determine the perovskite structures of SrTiO3−δ and Sr0.5Pr0.5Fe0.4–x Mg x Ti0.6O3−δ (x = 0, 0.1, and 0.2) and their electronic states. Further, the SPFMg0.2T with 20% Mg doping exhibited low dissociation energy, which ensures the fast and high ionic conduction in the electrolyte. Inclusively, Sr0.5Pr0.5Fe0.4Ti0.6O3−δ is a promising electrolyte for SOFCs, and its performance can be efficiently boosted via Mg doping to modulate the energy band structure.

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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.

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Facile, single-step, and scalable fabrication of large-area (i.e., ~20 cm2) TiO2 nanostructures (TNS) with excellent photocatalytic activity under UVA-light were prepared via electrochemical anodization. Anodization in glycerol-based electrolyte containing fluoride...

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