In situ Studies of Phase Evolution in (Pr_1-x Nd_x)₂ NiO₄ Electrodes with Various Interlayer Chemistries

Journal Article · Tue May 30 00:00:00 EDT 2017 · ECS Transactions (Online)

DOI:https://doi.org/10.1149/07801.0623ecst· OSTI ID:1440634

Dogdibegovic, Emir; Alabri, Nawf Saif; Wright, Christopher J.; Hardy, John S.; Coyle, Christopher A.; Horlick, Sam; Guan, Wanbing; Stevenson, J. W.; Zhou, Xiao-Dong

The interest in Pr2NiO4 (PNO) electrode stems from the necessity to develop active and stable oxygen electrodes (1-6) for solid oxide fuel cells (SOFCs) (7-9). PNO is known for its highly active nature (7,8,10), originating from its superior oxygen ion diffusion, surface exchange coefficient (2,7,9-11) and structural flexibility over a wide temperature region (from 500 to 900oC) (3,12). PNO electrode, however, does undergo structural evolution to form a higher order phase (Pr3Ni2O7) and Pr6O11 (PrOx) (8). The structural change has been a major concern because it possibly links with the performance degradation over long-term operation (7,8) Conventional x-ray diffraction (XRD) has been extensively used to investigate the structural evolution in nickelates in the form of powders or planar electrodes (8,10). This method has two major limitations due to its low flux and low resolution: (1) it might overlook the presence of additional phases in the system, which is especially true for praseodymium nickelates where XRD diffraction patterns of higher order phase(s) (e.g. Pr3Ni2O7) may overlap with the parent PNO phase, making quantification challenging (8); and (2) the quantification of phase evolution in electrochemically operated PNO electrode may show major structural change with almost 100% of the parent phase transition from the conventional XRD analysis, while the transmission electron microscopy (TEM) studies clearly show the regions of preserved PNO phase (7).

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1440634
• Report Number(s): PNNL-SA-128993; AA6040000
• Journal Information: ECS Transactions (Online), Vol. 78, Issue 1; ISSN 1938-6737
• Publisher: Electrochemical Society
• Country of Publication: United States
• Language: English