A Highly Active and Redox-Stable SrGdNi0.2Mn0.8O4±δ Anode with in Situ Exsolution of Nanocatalysts

Abstract

Layered perovskite SrGdNixMn1–xO4±δ phases were evaluated as new ceramic anode materials for use in solid oxide fuel cells (SOFCs). Hydrogen temperature-programmed reduction (H2-TPR) analysis of the SrGdNixMn1–xO4±δ (x = 0.2, 0.5, and 0.8) materials revealed that significant exsolution of Ni nanoparticles occurred in SrGdNi0.2Mn0.8O4±δ (SGNM28) in H2 at over 650 °C. Consistently, the SGNM28 on the LSGM electrolyte showed low electrode polarization resistance (1.79 Ω cm2) in H2 at 800 °C. Moreover, after 10 redox cycles at 750 °C, the electrode area specific resistance of the SGNM28 anode in H2 increased only 0.027 Ω·cm2 per cycle (1.78% degradation rate), indicating excellent redox stability in both reducing and oxidizing atmospheres. An LSGM-electrolyte-supported SOFC employing an SGNM28-Gd-doped ceria anode yielded a maximum power density of 1.26 W cm–2 at 850 °C, which is the best performance among the SOFCs with Ruddlesden–Popper-based ceramic anodes to date. After performance measurement, we observed...