The Role of Interlayer on the Catalytic Activity and Performance Stability of (Pr_(1-x)Nd_x)_2NiO_4 as Cathodes for Solid Oxide Fuel Cells

摘要

The use of doped ceria as an interlayer in solid oxide fuel cells (SOFCs) is ubiquitous, which provides a better thermal expansion match and prevents the interaction between cathode (e.g. LSCF) and electrolyte (e.g. YSZ). However, the role of ceria interlayer on the cathode phase durability, catalytic activity, and performance stability remains obscure. This is particularly true in nickelate cathodes (e.g. Pr_2NiO_4). In this work, the attention will be given to electrochemical properties in nickelate cathodes with various interlayers. Two new interlayer designs were investigated including (1) a thin Pr_6O_(11) film deposited on the surface of GDC and (2) a Pr-doped ceria interlayer. The latter design results in a 48% increase in cathode performance; and more importantly, it leads to zero degradation over long-term measurements. This is a tremendous improvement when compared to the performance degradation in cells with a GDC interlayer. The cathode-interlayer reaction was fully suppressed with PGCO, due to the intrinsic Pr enrichment in the interlayer, which contributed to suppressing the phase evolution in the electrode.