A perovskite-fluorite dual-phase cathode for boosting oxygen reduction reaction in NH3-Fueled solid oxide fuel cells.

Ammonia (NH 3), a promising carbon-free energy carrier, can be directly and efficiently converted into electricity in solid oxide fuel cells (SOFCs). However, the NH 3 -fueled SOFC (NH 3 –SOFC) still suffered from several difficulties, including sluggish oxygen reduction reaction (ORR) kinetics and poor cathode durability. In this study, we develop a LSCF-GDC dual-phase cathode with uniform distribution for NH 3 –SOFC. In comparison with commercial counterpart, the dual-phase cathode shows a lower ORR resistance of 0.114 Ω cm2 for at 700 °C due to reduced grain sizes and expanded triple-phase boundary (TPB) length. The resultant NH 3 –SOFC follows the H 2 oxidation process and delivers a comparable peak power density of 0.347 Wcm−2 to H 2 –SOFC at 700 °C, which is further improved to 0.516 Wcm−2 after 280 h activation at 0.7 V. Further operation of five thermal cycles between 700 and 500 °C results in a performance degradation, which can be explained by the microstructure changes of Ni-based anode rather than the dual-phase cathode. Moreover, the thermal cycled NH 3 –SOFC can maintain stable operation without current decay at constant 700 °C and 0.7 V in the subsequent 135 h, further demonstrating the robustness of the dual-phase cathode. Therefore, the introduction of GDC into self-assembled dual-phase cathode is an effective way to synergistically promote the electrochemical activity and durability of the cathode for NH 3 –SOFC. [ABSTRACT FROM AUTHOR]