A promising Ruddlesden–Popper oxide cathode for both proton-conducting and oxygen ionic-conducting solid oxide fuel cells

Intermediate and low-temperature solid oxide fuel cells (SOFCs) operated below 800 °C have attracted tremendous interest for their low component cost, preferable chemical compatibility of the components and considerable stability. In this paper, a Ruddlesden–Popper oxide with the composition of Nd1.8La0.2Ni0.74Cu0.21Ga0.05O4+δ (NLNCG) is developed as a cathode for intermediate and low-temperature SOFCs. NLNCG exhibits good chemical compatibility with both protonic electrolyte (BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb)) and oxygen ionic electrolyte (Ce0.9Gd0.1O2−δ (GDC)). Also, NLNCG can be applied as a cathode with low polarization resistance in both O-SOFCs based on GDC electrolyte and H-SOFCs based on BZCYYb electrolyte. In particular, the peak power density (PPD) of the cell NiO–BZCYYb|BZCYYb|NLNCG with an anode-supported configuration is 1.264 W cm−2 and the polarization resistance is 0.045 Ω cm2 at 800 °C. Therefore, NLNCG is a promising cathode for intermediate and low-temperature SOFCs.