Activity and Stability of (Pr1-xNdx)2NiO4 as Cathodes for Solid Oxide Fuel Cells: III. Crystal Structure, Electrical Properties, and Microstructural Analysis. Issue 2 (17th December 2016)

• Record Type: Journal Article
• Authors: Dogdibegovic, Emir; Cai, Qingsheng; Alabri, Nawf S.; Guan, Wanbing; Zhou, Xiao-Dong
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 2(2017)
• Page Start: F99
• Page End: F106
• Publication Date: 2016-12-17
• Subjects: cathode -- performance -- phase transition -- SOFC -- structure; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0581702jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : This study is to complement an early article (Dogdibegovic et al., J. Electrochem. Soc., 163 (13), F1344 (2016)) on the electrochemical activity and performance stability of (Pr1-x Ndx )2 NiO4+δ (PNNO) electrodes. Here, we report the crystal structure, electrical properties, and microstructures of PNNO series as the cathodes for solid oxide fuel cells. Rietveld refinements on powders ( x = 0, 0.25, 0.50, 0.75, and 1) show that the unit cell volume decreases with an increase in x, primarily due to a decrease in the c lattice parameter. Larger cell volume (∼1.50%) and higher total electrical conduction (40%) in Pr2 NiO4+δ are in favor with its mixed conducting properties during operation, but Pr2 NiO4+δ cathode exhibits a severe phase evolution. Substitution of Pr with Nd shows the suppression of phase evolution in both thermally annealed powders and electrodes. An increase in Nd content leads to a full preservation of the parent phase in both (Pr0.25 Nd0.75 )2 NiO4+δ and Nd2 NiO4 after 2, 500 hour annealing at elevated temperatures. Reaction with GDC buffer layer was also suppressed with the presence of Nd, which was shown by a reduction of Pr and Ni elemental diffusion into GDC bulk. STEM analysis confirms multiple phases present in an operated Pr2 NiO4+δ electrode, while suppressed phase transition was observed in electrodes with high Nd content.