Impact of Oxygen Deficiency on the Electrochemical Performance of K2NiF4-Type (La1-xSrx)(2)NiO4-delta Oxygen Electrodes
authors Kravchenko, E; Zakharchuk, K; Viskup, A; Grins, J; Svensson, G; Pankov, V; Yaremchenko, A
nationality International
journal CHEMSUSCHEM
author keywords ceramics; electrochemistry; fuel cells; layered compounds; nonstoichiometric compounds
keywords OXIDE FUEL-CELLS; X-RAY-DIFFRACTION; ELECTRICAL-PROPERTIES; HIGH-TEMPERATURE; CATHODE MATERIALS; TRANSPORT-PROPERTIES; CRYSTAL-CHEMISTRY; PHASE-DIAGRAM; MAGNETIC-PROPERTIES; LA2NIO4+DELTA
abstract Perovskite-related (La1-xSrx)(2)NiO4-delta (x= 0.5-0.8) phases were explored for possible use as oxygen electrodes in solid electrolyte cells with a main focus on the effect of oxygen deficiency on the electrocatalytic activity. (La1-xSrx)(2)NiO4-d solid solutions were demonstrated to preserve the K2NiF4-type tetragonal structure under oxidizing conditions. Acceptor-type substitution by Sr is compensated by the formation of oxygen vacancies and electron holes and progressively increases high-temperature oxygen nonstoichiometry, which reaches as high as d= 0.40 for x= 0.8 at 950 degrees C in air. The electrical conductivity of (La1-xSrx)(2)NiO4-d ceramics at 500-1000 degrees C and p(O-2) >= 10(-3) atm is p-type metallic-like. The highest conductivity, 300 Scm(-1) at 800 degrees C in air, is observed for x= 0.6. The average thermal expansion coefficients, (14.0-15.4) x 10(-6) K-1 at 25900 degrees C in air, are sufficiently low to ensure the thermomechanical compatibility with common solid electrolytes. The polarization resistance of porous (La1-xSrx)(2)NiO4-d electrodes applied on a Ce0.9Gd0.1O2-delta solid electrolyte decreases with increasing Sr concentration in correlation with the concentration of oxygen vacancies in the nickelate lattice and the anticipated level of mixed ionic-electronic conduction. However, this is accompanied by increasing reactivity between the cell components and necessitates the microstructural optimization of the electrode materials to reduce the electrode fabrication temperature.
publisher WILEY-V C H VERLAG GMBH
issn 1864-5631
isbn 1864-564X
year published 2017
volume 10
issue 3
beginning page 600
ending page 611
digital object identifier (doi) 10.1002/cssc.201601340
web of science category Chemistry, Multidisciplinary; GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY
subject category Chemistry; Science & Technology - Other Topics
unique article identifier WOS:000394572100015
  ciceco authors
  impact metrics
journal analysis (jcr 2017):
journal impact factor 7.411
5 year journal impact factor 7.575
category normalized journal impact factor percentile 89.341
dimensions (citation analysis):
altmetrics (social interaction):



 


Apoio

1suponsers_list_ciceco.jpg