Tungsten-Doped PrBaFe2O5+δ Double Perovskite as a High-Performance Electrode Material for Symmetrical Solid Oxide Fuel Cells

Double perovskite PrBaFe2O5+delta is a potential electrode material for symmetrical solid oxide fuel cells (Sym-SOFCs). This work aims to improve the Sym-SOFC performance by partially replacing Fe with W, forming a composition of (PrBa)(0.95)(Fe0.95W0.05)(2)O5+delta. Doping W keeps PrBaFe2O5+delta stability after high-temperature treatment in both air and hydrogen atmospheres, decreases the thermal expansion coefficient from 17.11 x 10(-6) to 14.59 x 10(-6) K-1, increases the content of oxygen species that are essential for the electrocatalytic reactions, and increases the chemical oxygen surface exchange coefficient by 121% at 800 degrees C. Consequently, doping W greatly improves the electrochemical performance, such as decreasing the areaspecific cathode polarization resistance by 35.5% to 0.031 Omega.cm(2) at 800 degrees C, reducing the anode polarization resistance by 17.7% to 0.123 Omega. cm(2), and increasing the peak power density of Sym-SOFCs by 32.5% to 1.02 W cm(-2) using humidified hydrogen as the fuel. The performance is much higher than those reported for Sym-SOFCs using PrBaFe2O5+delta doped with the other elements. Finally, the Sym-SOFCs are capable of directly using hydrocarbon fuels, providing peak power densities of 0.610, 0.624, and 0.448 W cm(-2) at 800 degrees C for syngas, ethane, and propane, respectively.

Automated summary

This research successfully improved the performance of Sym-SOFCs by partially replacing Fe with W, which increased oxygen species content essential for electrocatalytic reactions, decreased the thermal expansion coefficient, and enhanced the chemical oxygen surface exchange coefficient.